NSW workers compensation guidelines for the evaluation of permanent impairment

Part 1 - Intent and legislative basis for these guidelines

1.1 The reissued 4th edition of the NSW workers compensation guidelines for the evaluation of permanent impairment (catalogue no. WC00970) (the Guidelines) is made under s376 of the Workplace Injury Management and Workers Compensation Act 1998 (WIMWC Act) and commence on 1 March 2021 when the Personal Injury Commission is established. The Guidelines are to be used within the NSW workers compensation system to evaluate permanent impairment arising from work-related injuries and diseases.

The Guidelines adopt the 5th edition of the American Medical Association’s Guides to the Evaluation of Permanent Impairment (AMA5) in most cases. Where there is any deviation, the difference is defined in the Guidelines and the procedures detailed in each section are to prevail.

Part 2 - Principles of assessment

1.6 The following is a basic summary of some key principles of permanent impairment assessments:

1.7 Medical assessors are expected to be familiar with chapters 1 and 2 of AMA5, in addition to the information in this introduction.

1.8 The degree of permanent impairment that results from the injury/condition must be determined using the tables, graphs and methodology given in the Guidelines and the AMA5, where appropriate.

1.9 The Guidelines may specify more than one method that assessors can use to establish the degree of a claimant’s permanent impairment. In that case, assessors should use the method that yields the highest degree of permanent impairment. (This does not apply to gait derangement – see paragraphs 3.5 and 3.10 in the Guidelines).

Part 3 - Administrative process

Footnotes

* As of 1 September 2015, the workers compensation insurance regulatory functions of WorkCover NSW have been assumed by the State Insurance Regulatory Authority (SIRA).

AMA5 Chapter 16 (p 433) applies to the assessment of permanent impairment of the upper extremities, subject to the modifications set out below. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

• the Introduction in the Guidelines
• chapters 1 and 2 of AMA5
• the appropriate chapter(s) of the Guidelines for the body system they are assessing
• the appropriate chapter(s) of AMA5 for the body system they are assessing.

The Guidelines take precedence over AMA5.

Introduction

2.1 The upper extremities are discussed in AMA5 Chapter 16 (pp 433–521). This chapter provides guidelines on methods of assessing permanent impairment involving these structures. It is a complex chapter that requires an organised approach with careful documentation of findings.

2.2 Evaluation of anatomical impairment forms the basis for upper extremity impairment (UEI) assessment. The rating reflects the degree of impairment and its impact on the ability of the person to perform ADL. There can be clinical conditions where evaluation of impairment may be difficult. Such conditions are evaluated by their effect on function of the upper extremity, or, if all else fails, by analogy with other impairments that have similar effects on upper limb function.

The approach to assessment of the upper extremity and hand

2.3 Assessment of the upper extremity mainly involves clinical evaluation. Cosmetic and functional evaluations are performed in some situations. The impairment must be permanent and stable. The claimant will have a defined diagnosis that can be confirmed by examination.

2.4 The assessed impairment of a part or region can never exceed the impairment due to amputation of that part or region. For an upper limb, therefore, the maximum evaluation is 60% whole person impairment (WPI), the value for amputation through the shoulder.

2.5 Range of motion (ROM) is assessed as follows:

• A goniometer or inclinometer must be used, where clinically indicated.
• Passive ROM may form part of the clinical examination to ascertain clinical status of the joint, but impairment should only be calculated using active ROM measurements. Impairment values for degree measurements falling between those listed must be adjusted or interpolated.
• If the assessor is not satisfied that the results of a measurement are reliable, repeated testing may be helpful in this situation.
• If there is inconsistency in ROM, then it should not be used as a valid parameter of impairment evaluation. Refer to paragraph 1.36 in the Introduction.
• If ROM measurements at examination cannot be used as a valid parameter of impairment evaluation, the assessor should then use discretion in considering what weight to give other available evidence to determine if an impairment is present.

2.6 To achieve an accurate and comprehensive assessment of the upper extremity, findings should be documented on a standard form. AMA5 Figures 16-1a and 16-1b (pp 436–37) are extremely useful both to document findings and to guide the assessment process.

2.7 The hand and upper extremity are divided into regions: thumb, fingers, wrist, elbow and shoulder. Close attention needs to be paid to the instructions in AMA5 Figures 16-1a and 16-1b (pp 436–37) regarding adding or combining impairments.

2.8 AMA5 Table 16-3 (p 439) is used to convert upper extremity impairment to WPI. When the Combined Values Chart is used, the assessor must ensure that all values combined are in the same category of impairment (that is WPI, upper extremity impairment percentage, hand impairment percentage and so on). Regional impairments of the same limb (eg several upper extremity impairments) should be combined before converting to percentage WPI. (Note that impairments relating to the joints of the thumb are added rather than combined – AMA5 Section 16.4d ‘Thumb ray motion impairment’, p 454.)

Specific interpretation of AMA5 - the hand and upper extremity impairment of the upper extremity due to peripheral nerve disorders

2.9 If an upper extremity impairment results solely from a peripheral nerve injury, the assessor should not also evaluate impairment(s) from AMA5 Section 16.4 ‘Abnormal motion’ (pp 450–79) for that upper extremity. AMA5 Section 16.5 should be used for evaluating such impairments.

For evaluating peripheral nerve lesions, use AMA5 Table 16-15 (p 492) together with AMA5 tables 16-10 and 16-11 (pp 482 and 484).

The assessment of carpal tunnel syndrome post-operatively is undertaken in the same way as assessment without operation.

2.10 When applying AMA5 tables 16-10 (p 482) and 16-11 (pp 482 and 484) the examiner must use clinical judgement to estimate the appropriate percentage within the range of values shown for each severity grade. The maximum value is not applied automatically.

Impairment due to other disorders of the upper extremity

2.11 AMA5 Section 16.7 ‘Impairment of the upper extremity due to other disorders’ (pp 498–507) should be used only when other criteria (as presented in AMA5 sections 16.2–16.6, pp 441–98) have not adequately encompassed the extent of the impairments. Impairments from the disorders considered in AMA5 Section 16.7 are usually estimated using other criteria. The assessor must take care to avoid duplication of impairments.

2.12 AMA5 Section 16.7 (impairment of the upper extremities due to other disorders) notes ‘the severity of impairment due to these disorders is rated separately according to Table 16-19 through 16-30 and then multiplied by the relative maximum value of the unit involved, as specified in Table 16-18’. This statement should not include tables 16-25 (carpal instability), 16-26 (shoulder instability) and 16-27 (arthroplasty), noting that the information in these tables is already expressed in terms of upper extremity impairment.

2.13 Strength evaluation, as a method of upper extremity impairment assessment, should only be used in rare cases and its use justified when loss of strength represents an impairing factor not adequately considered by more objective rating methods. If chosen as a method, the caveats detailed on AMA5 p 508 under the heading ‘16.8a Principles’ need to be observed – ie decreased strength cannot be rated in the presence of decreased motion, painful conditions, deformities and absence of parts (eg thumb amputation).

Conditions affecting the shoulder region

2.14 Most shoulder disorders with an abnormal range of movement are assessed according to AMA5 Section 16.4 ‘Evaluating abnormal motion’. (Please note that AMA5 indicates that internal and external rotation of the shoulder are to be measured with the arm abducted in the coronal plane to 90 degrees, and with the elbow flexed to 90 degrees. In those situations where abduction to 90 degrees is not possible, symmetrical measurement of rotation is to be carried out at the point of maximal abduction.)

Rare cases of rotator cuff injury, where the loss of shoulder motion does not reflect the severity of the tear, and there is no associated pain, may be assessed according to AMA5 Section 16.8c ‘Strength evaluation’. Other specific shoulder disorders where the loss of shoulder motion does not reflect the severity of the disorder, associated with pain, should be assessed by comparison with other impairments that have similar effect(s) on upper limb function.

As noted in AMA5 Section 16.7b ‘Arthroplasty’, ‘In the presence of decreased motion, motion impairments are derived separately and combined with the arthroplasty impairment’. This includes those arthroplasties in AMA5 Table 16-27 designated as (isolated).

Please note that in AMA5 Table 16-27 (p 506) the figure for resection arthroplasty of the distal clavicle (isolated) has been changed to 5% upper extremity impairment, and the figure for resection arthroplasty of the proximal clavicle (isolated) has been changed to 8% upper extremity impairment.

Please note that in AMA5 Table 16-18 (p 499) the figures for impairment suggested for the sternoclavicular joint have been changed from 5% upper extremity impairment and 3% whole person impairment, to 25% upper extremity impairment and 15% whole person impairment.

2.15 Ruptured long head of biceps shall be assessed as an upper extremity impairment (UEI) of 3%UEI or 2%WPI where it exists in isolation from other rotator cuff pathology. Impairment for ruptured long head of biceps cannot be combined with any other rotator cuff impairment or with loss of range of movement.

2.16 Diagnosis of impingement is made on the basis of positive findings on appropriate provocative testing and is only to apply where there is no loss of range of motion. Symptoms must have been present for at least 12 months. An impairment rating of 3% UEI or 2% WPI shall apply.

Fractures involving joints

2.17 Displaced fractures involving joint surfaces are generally to be rated by range of motion. If, however, this loss of range is not sufficient to give an impairment rating, and movement is accompanied by pain and there is 2mm or more displacement, allow 2% UEI (1% WPI).

Epicondylitis of the elbow

2.18 This condition is rated as 2% UEI (1% WPI). In order to assess impairment in cases of epicondylitis, symptoms must have been present for at least 18 months. Localised tenderness at the epicondyle must be present and provocative tests must also be positive. If there is an associated loss of range of movement, these figures are not combined, but the method giving the highest rating is used.

Resurfacing procedures

2.19 No additional impairment is to be awarded for resurfacing procedures used in the treatment of localised cartilage lesions and defects in major joints.

Calculating motion impairment

2.20 When calculating impairment for loss of range of movement, it is most important to always compare measurements of the relevant joint(s) in both extremities. If a contralateral ‘normal/uninjured’ joint has less than average mobility, the impairment value(s) corresponding to the uninvolved joint serves as a baseline and is subtracted from the calculated impairment for the involved joint. The rationale for this decision should be explained in the assessor’s report (see AMA5 Section 16.4c, p 543).

Complex regional pain syndrome (upper extremity)

2.21 Complex regional pain syndrome types 1 and 2 should be assessed using the method in Chapter 17 of the Guidelines.

AMA5 Chapter 17 (p 523) applies to the assessment of permanent impairment of the lower extremities, subject to the modifications set out below. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

• the Introduction in the Guidelines
• chapters 1 and 2 of AMA5
• the appropriate chapter(s) of the Guidelines for the body system they are assessing
• the appropriate chapter(s) of AMA5 for the body system they are assessing.

The Guidelines take precedence over AMA5.

Introduction

3.1 The lower extremities are discussed in AMA5 Chapter 17 (pp 523–564). This section is complex and provides a number of alternative methods of assessing permanent impairment involving the lower extremity. An organised approach is essential.

The approach to assessment of the lower extremity

3.2 Assessment of the lower extremity involves physical evaluation, which can use a variety of methods. In general, the method should be used that most specifically addresses the impairment present. For example, impairment due to a peripheral nerve injury in the lower extremity should be assessed with reference to that nerve rather than by its effect on gait.

3.3 There are several different forms of evaluation that can be used, as indicated inAMA5 sections 17.2b to 17.2n (pp 528–54). AMA5 Table 17-2 (p 526) indicates which evaluation methods can be combined and which cannot. It may be possible to perform several different evaluations, as long as they are reproducible and meet the conditions specified below and in AMA5. The most specific method of impairment assessment should be used. (Please note that in Table 17-2, the boxes in the fourth row (on muscle strength) and seventh column (on amputation) should be closed boxes [x] rather than open boxes [ ].)

3.4 It is possible to use an algorithm to aid in the assessment of lower extremity impairment (LEI). Use of a worksheet is essential. Table 3.5 at the end of this chapter is such a worksheet and may be used in assessment of permanent impairment of the lower extremity.

3.5 In the assessment process, the evaluation giving the highest impairment rating is selected. That may be a combined impairment in some cases, in accordance with the AMA5 Table 17-2 ‘Guide to the appropriate combination of evaluation methods’, using the Combined Values Chart on pp 604–06 of AMA5.

3.6 When the Combined Values Chart is used, the assessor must ensure that all values combined are in the same category of impairment rating (ie percentage of WPI, percentage of lower extremity impairment, foot impairment percentage, and so on). Regional impairments of the same limb (eg several lower extremity impairments) should be combined before converting to a percentage of whole person impairment (WPI).

3.7 AMA5 Table 17-2 (p 526) AMA5) needs to be referred to frequently to determine which impairments can be combined and which cannot. The assessed impairment of a part or region can never exceed the impairment due to amputation of that part or region. For the lower limb, therefore, the maximum evaluation is 40% WPI, the value for proximal above-knee amputation.

Specific interpretation of AMA5 – the lower extremity

AMA5 Chapter 15 (p 373) applies to the assessment of permanent impairment of the spine, subject to the modifications set out below. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

• the Introduction in the Guidelines
• chapters 1 and 2 of AMA5
• the appropriate chapter(s) of the Guidelines for the body system they are assessing.
• the appropriate chapter(s) of AMA5 for the body system they are assessing.
• The Guidelines take precedence over AMA5.

Introduction

4.1 The spine is discussed in Chapter 15 of AMA5 (pp 373–431). That chapter presents two methods of assessment, the diagnosis-related estimates method and the range of motion method. Evaluation of impairment of the spine is only to be done using diagnosis-related estimates (DREs).

4.2 The DRE method relies especially on evidence of neurological deficits and less common, adverse structural changes, such as fractures and dislocations. Using this method, DREs are differentiated according to clinical findings that can be verified by standard medical procedures.

4.3 The assessment of spinal impairment is made when the person’s condition has stabilised and has reached maximum medical improvement. This is considered to occur when the worker’s condition is well stabilised and unlikely to change substantially in the next year, with or without medical treatment. If surgery has been performed, the outcome of the surgery as well as structural inclusions must be taken into consideration when making the assessment.

Assessment of the spine

4.4 The assessment should include a comprehensive, accurate history, a review of all pertinent records available at the assessment, a comprehensive description of the individual’s current symptoms and their relationship to activities of daily living (ADL); a careful and thorough physical examination; and all findings of relevant laboratory, imaging, diagnostic and ancillary tests available at the assessment. Imaging findings that are used to support the impairment rating should be concordant with symptoms and findings on examination. The assessor should record whether diagnostic tests and radiographs were seen or whether they relied solely on reports.

4.5 The DRE model for assessment of spinal impairment should be used. The range of motion model (AMA5 sections 15.8–15.13 inclusive, pp 398–427) should not be used.

4.6 If a person has spinal cord or cauda equina damage, including bowel, bladder and/or sexual dysfunction, he or she is assessed according to the method described in AMA5 Section 15.7 and AMA5 Table 15.6 (a)–(g) (pp 395–98).

4.7 If an assessor is unable to distinguish between two DRE categories, then the higher of those two categories should apply. The reasons for the inability to differentiate should be noted in the assessor’s report.

4.8 Possible influence of future treatment should not form part of the impairment assessment. The assessment should be made on the basis of the person’s status at the time of interview and examination, if the assessor is convinced that the condition is stable and permanent. Likewise, the possibility of subsequent deterioration, as a consequence of the underlying condition, should not be factored into the impairment evaluation. Commentary can be made regarding the possible influence, potential or requirements for further treatment, but this does not affect the assessment of the individual at the time of impairment evaluation.

4.9 All spinal impairments are to be expressed as a percentage of WPI.

4.10 AMA5 Section 15.1a (pp 374–77) is a valuable summary of history and physical examination, and should be thoroughly familiar to all assessors.

4.11 The assessor should include in the report a description of how the impairment rating was calculated, with reference to the relevant tables and figures used.

4.12 The optimal method to measure the percentage compression of a vertebral body is a well-centred plain X-ray. Assessors should state the method they have used. The loss of vertebral height should be measured at the most compressed part and must be documented in the impairment evaluation report. The estimated normal height of the compressed vertebra should be determined, where possible, by averaging the heights of the two adjacent (unaffected and normal) vertebrae.

Specific interpretation of AMA5

4.13 The range-of-motion (ROM) method is not used, hence any reference to this is omitted (includingAMA5 Table 15-7, p 404).

4.14 Motion segment integrity alteration can be either increased translational or angular motion, or decreased motion resulting from developmental changes, fusion, fracture healing, healed infection or surgical arthrodesis. Motion of the individual spine segments cannot be determined by a physical examination, but is evaluated with flexion and extension radiography.

4.15 The assessment of altered motion segment integrity is to be based upon a report of trauma resulting in an injury, and not on developmental or degenerative changes.

4.16 When routine imaging is normal and severe trauma is absent, motion segment disturbance is rare. Thus, flexion and extension imaging is indicated only when a history of trauma or other imaging leads the physician to suspect alteration of motion segment integrity.

DRE definitions of clinical findings

4.17  The preferred method for recording ROM is as a fraction or percentage of the range or loss of the range. For example, either ‘cervical movement was one half (or 50%) of the normal range of motion’ or ‘there was a loss of one half (or 50%) of the normal range of movement of the cervical spine’.

4.18 DRE II is a clinical diagnosis based upon the features of the history of the injury and clinical features. Clinical features which are consistent with DRE II and which are present at the time of assessment include radicular symptoms in the absence of clinical signs (that is, non-verifiable radicular complaints), muscle guarding or spasm, or asymmetric loss of range of movement. Localised (not generalised) tenderness may be present. In the lumbar spine, additional features include a reversal of the lumbosacral rhythm when straightening from the flexed position and compensatory movement for an immobile spine, such as flexion from the hips. In assigning category DRE II, the assessor must provide detailed reasons why the category was chosen.

4.19 Asymmetric or non-uniform loss of ROM may be present in any of the three planes of spinal movement. Asymmetry during motion caused by muscle guarding or spasm is included in the definition.

Asymmetric loss of ROM may be present for flexion and extension. For example, if cervical flexion is half the normal range (loss of half the normal range) and cervical extension is one-third of the normal range (loss of two thirds of the range), asymmetric loss of ROM may be considered to be present.

4.20 While imaging and other studies may assist medical assessors in making a diagnosis, the presence of a morphological variation from ‘normal’ in an imaging study does not confirm the diagnosis. To be of diagnostic value, imaging studies must be concordant with clinical symptoms and signs. In other words, an imaging test is useful to confirm a diagnosis, but an imaging study alone is insufficient to qualify for a DRE category (excepting spinal fractures).

4.21 The clinical findings used to place an individual in a DRE category are described in AMA5 Box 15-1 (pp 382–83).

The reference to ‘electro-diagnostic verification of radiculopathy’ should be disregarded.

(The use of electro-diagnostic procedures such as electromyography is proscribed as an assessment aid for decisions about the category of impairment into which a person should be placed. It is considered that competent assessors can make decisions about which DRE category a person should be placed in from the clinical features alone. The use of electro-diagnostic differentiators is generally unnecessary).

4.22 The cauda equina syndrome is defined in Box 15.1 in Chapter 15 of AMA5 (p 383) as ‘manifested by bowel or bladder dysfunction, saddle anaesthesia and variable loss of motor and sensory function in the lower limbs’. For a cauda equina syndrome to be present there must be bilateral neurological signs in the lower limbs and sacral region. Additionally, there must be a radiological study which demonstrates a lesion in the spinal canal, causing a mass effect on the cauda equina with compression of multiple nerve roots. The mass effect would be expected to be large and significant. A lumbar MRI scan is the diagnostic investigation of choice for this condition. A cauda equina syndrome may occasionally complicate lumbar spine surgery when a mass lesion will not be present in the spinal canal on radiological examination.

4.23 The cauda equina syndrome and neurogenic bladder disorder are to be assessed by the method prescribed in the spine chapter of AMA5 Section 15.7 (pp 395–98). For an assessment of neurological impairment of bowel or bladder, there must be objective evidence of spinal cord or cauda equina injury.

Applying the DRE method

4.24 The specific procedures and directions section of AMA5 Section 15.2a (pp 380–81) indicates the steps that should be followed to evaluate impairment of the spine (excluding references to the ROM method). Table 4.1 below is a simplified version of that section, incorporating the amendments listed above.

4.25 Common developmental findings, spondylosis, spondylolisthesis and disc protrusions without radiculopathy occur in 7%, 3% and up to 30% of cases involving individuals up to the age of 40 respectively (AMA5, p 383). Their presence does not of itself mean that the individual has an impairment due to injury.

4.26 Loss of sexual function should only be assessed where there is other objective evidence of spinal cord, cauda equina or bilateral nerve root dysfunction. The ratings are described in AMA5 Table 15-6 (pp 396–97). There is no additional impairment rating system for loss of sexual function in the absence of objective neurological findings. Loss of sexual function is not assessed as an ADL.

4.27 Radiculopathy is the impairment caused by malfunction of a spinal nerve root or nerve roots. In general, in order to conclude that radiculopathy is present, two or more of the following criteria should be found, one of which must be major (major criteria in bold):

• loss or asymmetry of reflexes
• muscle weakness that is anatomically localised to an appropriate spinal nerve root distribution
• reproducible impairment of sensation that is anatomically localised to an appropriate spinal nerve root distribution
• positive nerve root tension (AMA5 Box 15-1, p 382)
• muscle wasting – atrophy (AMA5 Box 15-1, p 382)
• findings on an imaging study consistent with the clinical signs (AMA5, p 382).

4.28 Radicular complaints of pain or sensory features that follow anatomical pathways but cannot be verified by neurological findings (somatic pain, non-verifiable radicular pain) do not alone constitute radiculopathy.

4.29 Global weakness of a limb related to pain or inhibition or other factors does not constitute weakness due to spinal nerve malfunction.

4.30 Vertebral body fractures and/or dislocations at more than one vertebral level are to be assessed as follows:

• Measure the percentage loss of vertebral height at the most compressed part for each vertebra, then
• Add the percentage loss at each level:
  • total loss of more than 50% = DRE IV
  • total loss of 25% to 50% = DRE III
  • total loss of less than 25% = DRE II
• If radiculopathy is present then the person is assigned one DRE category higher.

One or more end plate fractures in a single spinal region without measurable compression of the vertebral body are assessed as DRE category II.

Posterior element fractures (excludes fractures of transverse processes and spinous processes) at multiple levels are assessed as DRE Ill.

4.31 Displaced fractures of transverse or spinous processes at one or more levels are assessed as DRE category II because the fracture does not disrupt the spinal canal (AMA5, p 385) and do not cause multilevel structural compromise.

4.32 Within a spinal region, separate spinal impairments are not combined. The highest-value impairment within the region is chosen. Impairments in different spinal regions are combined using the combined values chart (AMA5, pp 604-06).

If there are adjacent vertebral fractures at the transition zones (C7/T1, T12/L1), the methodology in paragraph 4.30 in the Guidelines is to be adopted. For fractures of C7 and T1, use the WPI ratings for the cervical spine (AMA5 Chapter 15, Table 15-5, p 392). For fractures of T12 and L1, use the WPI rating for the thoracic spine (AMA5 Chapter 15, Table 15-4, p 389).

4.33 Impact of ADL. Tables 15-3, 15-4 and 15-5 of AMA5 give an impairment range for DREs II to V. Within the range, 0%, 1%, 2% or 3% WPI may be assessed using paragraphs 4.34 and 4.35 below. An assessment of the effect of the injury on ADL is not solely dependent on self-reporting, but is an assessment based on all clinical findings and other reports.

4.34 The following diagram should be used as a guide to determine whether 0%, 1%, 2% or 3% WPI should be added to the bottom of the appropriate impairment range. This is only to be added if there is a difference in activity level as recorded and compared to the worker’s status prior to the injury.

4.35 The diagram is to be interpreted as follows:

Increase base impairment by:

• 3% WPI if the worker’s capacity to undertake personal care activities such as dressing, washing, toileting and shaving has been affected
• 2% WPI if the worker can manage personal care, but is restricted with usual household tasks, such as cooking, vacuuming and making beds, or tasks of equal magnitude, such as shopping, climbing stairs or walking reasonable distances
• 1% WPI for those able to cope with the above, but unable to get back to previous sporting or recreational activities, such as gardening, running and active hobbies etc.

4.36 For a single injury, where there has been more than one spinal region injured, the effect of the injury on ADL is assessed once only.

For injuries to one spinal region on different dates, the effect of the injury on ADL is assessed for the first injury. If, following the second injury, there is a worsening in the ability to perform ADL, the appropriate adjustments are made within the range. For example, if WPI for ADL is assessed as 1% following the first injury and 3% after the second injury, then WPI for ADL for the second injury is assessed as 2%.

For injuries to different spinal regions on different dates, where there is a worsening of ability to perform ADL after the second injury, additional impairment may be assessed. For example, if ADL for a cervical spine injury is assessed as 1%, and an assessment of a subsequent lumbar spine injury determined 3% WPI for ADL, then WPI for impact on ADLs for the lumbar injury is assessed as 2% WPI.

4.37 Effect of surgery: AMA5 tables 15-3 to 15-5 (pp 384, 389 and 392) do not adequately account for the effect of surgery on the impairment rating for certain disorders of the spine. The assessor should note that:

• Surgical decompression for spinal stenosis is DRE category III (AMA5 Table 15-3, 15-4 or 15-5)
• Operations where the radiculopathy has resolved are considered under the DRE category III (AMA5 Table 15-3, 15-4 or 15-5).
• Operations for spinal fusion (successful or unsuccessful) are considered under DRE category IV (AMA5 Table 15-3, 15-4 or 15-5)
• DRE category V is not to be used following spinal fusion where there is a persisting radiculopathy. Instead, use Table 4.2 in the Guidelines
• Radiculopathy persisting after surgery is not accounted for by AMA5 Table 15-3, and incompletely by tables 15-4 and 15-5, which only refer to radiculopathy that has improved following surgery.

Table 4.2 indicates the additional ratings which should be combined with the rating determined using the DRE method where an operation for an intervertebral disc prolapse, spinal canal stenosis or spinal fusion has been performed.

Example 15-4 in AMA5 (p 386) should therefore be ignored.

4.38 Disc replacement surgery: The impairment resulting from this procedure is to be equated to that from a spinal fusion.

4.39 Arthritis: See paragraphs 3.19 – 3.24, Chapter 3 of the Guidelines.

4.40 Posterior spacing or stabilisation devices: The insertion of such devices does not warrant any additional WPI.

4.41 Spinal cord stimulator or similar device: The insertion of such devices does not warrant any additional WPI.

4.42 Impairment due to pelvic fractures should be evaluated with reference to the following table, which replaces AMA5 Table 15-19.

AMA5 Chapter 13 (p 305), applies to the assessment of permanent impairment of the nervous system, subject to the modifications set out below. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

• the Introduction in the Guidelines
• chapters 1 and 2 of AMA5
• the appropriate chapter(s) of the Guidelines for the body system they are assessing
• the appropriate chapter(s) of AMA5 for the body system they are assessing.

The Guidelines take precedence over AMA5.

Introduction

5.1 AMA5 Chapter 13 ‘The central and peripheral nervous system’ (pp 305–56), provides guidelines on methods of assessing permanent impairment involving the central nervous system. It is logically structured and consistent with the usual sequence of examination of the nervous system. Cerebral functions are discussed first, followed by the cranial nerves, station, gait and movement disorders, the upper extremities related to central impairment, the brain stem, the spinal cord and the peripheral nervous system, including neuromuscular junction and muscular system. A summary concludes the chapter.

5.2 Spinal cord injuries are to be assessed using AMA5Chapter 15. Table 15-6 (pp 396–97) is to be used for evaluation of spinal cord injuries. These impairments, once selected, are then combined with the corresponding additional spinal impairment from DRE categories II–V for cervical and lumbar impairment and categories II–IV for thoracic impairment to obtain an exact total value.

5.3 Impairments of the peripheral nervous system are assessed by using the relevant parts of the upper extremity, lower extremity and spine sections of AMA5.

The approach to assessment of permanent neurological impairment

5.4 AMA5 Chapter 13 disallows combination of cerebral impairments. However, for the purpose of the Guidelines, cerebral impairments should be evaluated and combined as follows:

• consciousness and awareness
• mental status, cognition and highest integrative function
• aphasia and communication disorders
• emotional and behavioural impairments.

The assessor should take care to be as specific as possible and not to double-rate the same impairment, particularly in the mental status and behavioural categories.

These impairments are to be combined using the Combined Values Chart (AMA5, pp 604–06). These impairments should then be combined with other neurological impairments indicated in AMA5 Table 13-1 (p 308).

5.5 AMA5 sections 13.5–13.6 (pp 336–40) should be used for cerebral, basal ganglia, cerebellar or brain stem impairments. This section, therefore, covers hemiplegia, monoplegia (arm or leg), and upper or lower limb impairment due to incoordination, or movement disorder due to brain injury.

5.6 If a person has a spinal injury with spinal cord or cauda equina, bilateral nerve root or lumbosacral plexus injury causing bowel, bladder and/or sexual dysfunction, he or she is assessed according to the method described in AMA5Section 15.7 and Table 15-6 (a)–(g) (pp 395–98).

5.7 Complex regional pain syndrome types 1 and 2 are to be assessed using the method in Chapter 17 of the Guidelines.

5.8 AMA5 Chapter 13, on the nervous system, lists many impairments where the range for the associated WPI is 0–9% or 0–14%. Where there is a range of impairment percentages listed, the assessor should nominate an impairment percentage based on the complete clinical circumstances revealed during the consultation, and in relation to all other available information.

Specific interpretation of AMA5

5.9 In assessing disturbances of mental status and integrative functioning; and emotional or behavioural disturbances; disturbances in the level of consciousness and awareness; disturbances of sleep and arousal function; and disorders of communication (AMA5 sections 13.3a, 13.3c, 13.3d, 13.3e and 13.3f; pp 309–311 and 317–327), the assessor should make ratings based on clinical assessment and the results of neuropsychometric testing, where available.

For traumatic brain injury, there should be evidence of a severe impact to the head, or that the injury involved a high-energy impact.

Clinical assessment must include at least one of the following:

• significant medically verified abnormalities in the Glasgow Coma Scale score
• significant medically verified duration of post-traumatic amnesia
• significant intracranial pathology on CT scan or MRI.

Neuropsychological testing should be conducted by a registered clinical neuropsychologist who is a member, or is eligible for membership, of the Australian Psychological Society’s College of Clinical Neuropsychology. Neuropsychological test data is to be considered in the context of the overall clinical history, examination and radiological findings, and not in isolation.

5.10 Assessment of arousal and sleep disorders (AMA5 Section 13.3c, pp 317–319): refers to assessment of primary sleep disorders following neurological injury. The assessor should make ratings of arousal and sleep disorders based on the clinical assessment that would normally have been done for clinically significant disorders of this type (ie sleep studies or similar tests).

5.11 Olfaction and taste: The assessor should use AMA5 Chapter 11, Section 11.4c (p 262) to assess olfaction and taste, for which a maximum of 5% WPI is allowable for total loss of either sense. The effect on activities of daily living should be considered.

5.12 Visual impairment assessment (AMA4 Chapter 8, pp 209–22): An ophthalmologist should assess all impairments of visual acuity, visual fields, extra-ocular movements or diplopia.

5.13 Trigeminal nerve assessment (AMA5, p 331): Sensory impairments of the trigeminal nerve should be assessed with reference to AMA5 Table 13-11 (p 331). The words ‘sensory loss or dysaesthesia’ should be added to the table after the words ‘neuralgic pain’ in each instance. Lesions of the ophthalmic division of the trigeminal nerve with impairment of corneal sensation should be apportioned with extra weighting.

If present, motor loss for the trigeminal nerve should be assessed in terms of its impact on mastication and deglutition (AMA5, p 262).

For bilateral injury to the trigeminal nerves, assess each side separately and combine the assessed WPIs.

5.14 Spinal accessory nerve: AMA5 provides insufficient reference to the spinal accessory nerve (cranial nerve XI). This nerve supplies the trapezius and sternomastoid muscles. For loss of use of the nerve to trapezius, the assessor should refer to AMA5 Chapter 16 on upper limb assessment, and a maximum of 10% impairment of the upper limb may be assigned. For additional loss of use of sternomastoid, a maximum of 3% upper limb impairment may be added.

5.15 Impairment of sexual function caused by severe traumatic brain injury is to be assessed using AMA5 Table 13-21 (p 342). For spinal cord, nerve root or more peripheral nerve injury, sexual impairment should only be assessed where there is appropriate objective evidence of spinal cord, cauda equina or bilateral nerve root dysfunction, or lumbosacral plexopathy.

5.16 Impairment due to miscellaneous peripheral nerves should be evaluated with reference to the following table.

AMA5 Chapter 11 (p 245), applies to the assessment of permanent impairment of the ear (with the exception of hearing impairment), nose, throat and related structures, subject to the modifications set out below. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

• the Introduction in the Guidelines
• chapters 1 and 2 of AMA5
• the appropriate chapter(s) of the Guidelines for the body system they are assessing.
• the appropriate chapter(s) of AMA5 for the body system they are assessing.

The Guidelines take precedence over AMA5.

Introduction

6.1 AMA5 Chapter 11 (pp 245–75) details the assessment of the ear, nose, throat and related structures. With the exception of hearing impairment, which is dealt with in Chapter 9 of the Guidelines, AMA5 Chapter 11 should be followed in assessing permanent impairment, with the variations included below.

6.2 The level of impairment arising from conditions that are not work-related needs to be assessed by the medical assessor and taken into consideration in determining the level of permanent impairment. The level at which pre-existing conditions and lifestyle activities, such as smoking, contribute to the level of permanent impairment requires judgement on the part of the clinician undertaking the impairment assessment. The manner in which any deduction for these is applied needs to be recorded in the assessing specialist’s report.

The ear

6.3 Equilibrium is assessed according to AMA5 Section 11.2b (pp 252–55), but add these words to AMA5 Table 11-4, class 2 (p 253): ‘without limiting the generality of the above, a positive Hallpikes test is a sign and an objective finding’.

The face (AMA5, pp 255-59)

6.4 AMA5 Table 11-5 (p 256) should be replaced with Table 6.1, below, when assessing permanent impairment due to facial disorders and/or disfigurement.

6.5 In AMA5 example 11-11 (p 257), add the words ‘visual impairment related to enophthalmos must be assessed by an Ophthalmologist’.

The nose, throat and related structures

AMA5 Chapter 7 (p 143) applies to the assessment of permanent impairment of the urinary and reproductive systems, subject to the modifications set out below. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

• the Introduction in the Guidelines
• chapters 1 and 2 of AMA5
• the appropriate chapter(s) of the Guidelines for the body system they are assessing
• the appropriate chapter(s) of AMA5 for the body system they are assessing.

The Guidelines take precedence over AMA5.

Introduction

7.1 AMA5 Chapter 7 (pp 143–71) provides clear details for assessment of the urinary and reproductive systems. Overall, the chapter should be followed in assessing permanent impairment, with the variations included below.

7.2 For both male and female sexual dysfunction, identifiable pathology should be present for an impairment percentage to be given.

Urinary diversion

7.3 AMA5 Table 7-2 (p 150) should be replaced with Table 7.1, below, when assessing permanent impairment due to urinary diversion disorders. This table includes ratings for neobladder and continent urinary diversion.

7.4 Continent urinary diversion is defined as a continent urinary reservoir constructed of small or large bowel with a narrow catheterisable cutaneous stoma through which it must be emptied several times a day.

Bladder

7.5 AMA5 Table 7-3 (p 151) should be replaced with Table 7.2, below, when assessing permanent impairment due to bladder disease. This table includes ratings involving urge and total incontinence (defined in 7.8 of the Guidelines).

7.6 AMA5 example 7-16 (p 151) should be reclassified as an example of class 2, as the urinary frequency is more than every two hours and continuous treatment would be expected.

Urethra

7.7 AMA5 Table 7-4 (p 153) should be replaced with Table 7.3 below when assessing permanent impairment due to urethral disease. This table includes ratings involving stress incontinence.

Urinary incontinence

7.8 Urge urinary incontinence is the involuntary loss of urine associated with a strong desire to void. Stress urinary incontinence is the involuntary loss of urine occurring with clinically demonstrable raised intra-abdominal pressure. It is expected that urinary incontinence of a regular or severe nature (necessitating the use of protective pads or appliances) will be assessed as follows:

The highest scoring condition is to be used to assess impairment - combinations are not allowed.

Male reproductive organs

Female reproductive organs

AMA5 Chapter 5 (p 87) applies to the assessment of permanent impairment of the respiratory system, subject to the modifications set out below. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

• the Introduction in the Guidelines
• chapters 1 and 2 of AMA5
• the appropriate chapter(s) of the Guidelines for the body system they are assessing
• the appropriate chapter(s) of AMA5 for the body system they are assessing.

The Guidelines take precedence over AMA5.

Introduction

8.1 AMA5 Chapter 5 provides a useful summary of the methods for assessing permanent impairment arising from respiratory disorders.

8.2 The level of impairment arising from conditions that are not work-related needs to be assessed by the medical assessor and taken into consideration in determining the level of permanent impairment. The level at which pre-existing conditions and lifestyle activities, such as smoking, contribute to the level of permanent impairment requires judgement on the part of the clinician undertaking the impairment assessment. The manner in which any deduction for these is applied needs to be recorded in the assessing specialist’s report.

Examinations, clinical studies and other tests for evaluating respiratory disease (AMA5 Section 5.4)

8.3 AMA5 tables 5-2b, 5-3b, 5-4b, 5-5b, 5-6b and 5-7b (pp 95–100) give the lower limits of normal values for pulmonary function tests. These are used in AMA5 Table 5-12 (p 107) to determine the impairment classification for respiratory disorders.

8.4 Classes 2, 3 and 4 in Table 5-12 list ranges of whole person impairment (WPI). The assessor should nominate the nearest whole percentage based on the complete clinical circumstances when selecting within the range.

Asthma (AMA5 Section 5.5)

8.5 In assessing permanent impairment arising from occupational asthma, the assessor will require evidence from the treating physician that:

• at least three lung function tests have been performed over a six-month period and that the results were consistent and repeatable over that period
• the worker has received maximal treatment and is compliant with his or her medication regimen.

8.6 Bronchial challenge testing should not be performed as part of the impairment assessment. Therefore, in AMA5 Table 5-9 (p 104), ignore column 4 (PC20 mg/mol or equivalent, etc.).

8.7 Permanent impairment due to asthma is rated by the score for the best post-bronchodilator forced expiratory volume in one second (FEV1) (score in column 2, AMA5 Table 5-9) plus per cent of FEV1 (score in column 3) plus minimum medication required (score in column 5). The total score derived is then used to assess the per cent impairment in AMA5 Table 5-10 (p 104).

Obstructive sleep apnoea (AMA Section 5.6)

8.8 This section needs to be read in conjunction with AMA5 sections 11.4 (p 259) and 13.3c (p 317).

8.9 Before permanent impairment can be assessed, the person must have appropriate assessment and treatment by an ear, nose and throat surgeon and a respiratory physician who specialises in sleep disorders.

8.10 The degree of permanent impairment due to sleep apnoea should be calculated with reference to AMA5 Table 13-4 (p 317).

Hypersensitivity pneumonitis (AMA5 Section 5.7)

8.11 Permanent impairment arising from disorders included in this section are assessed according to the impairment classification in AMA5 Table 5-12 (p 107).

Pneumoconiosis (AMA5 Section 5.8)

8.12 This section is excluded from the Guidelines, as these are the subject of the Dust Diseases Legislation.

Lung cancer (AMA5 Section 5.9)

8.13 Permanent impairment due to lung cancer should be assessed at least six months after surgery. AMA5 Table 5-12 (p 107), not Table 5-11, should be used for assessment of permanent impairment.

8.14 Persons with residual lung cancer after treatment are classified in respiratory impairment class 4 (AMA5 Table 5-12).

Permanent impairment due to respiratory disorders (AMA5 Section 5.10)

8.15 AMA5 Table 5-12 should be used to assess permanent impairment for respiratory disorders. The pulmonary function tests listed in Table 5-12 must be performed under standard conditions. Exercise testing is not required on a routine basis.

8.16 An isolated abnormal diffusing capacity for carbon monoxide (DCO) in the presence of otherwise normal results of lung function testing should be interpreted with caution and its aetiology should be clarified.

AMA5 Chapter 11 (p 245) applies to the assessment of permanent impairment of hearing, subject to the modifications set out below. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

• the Introduction in the Guidelines
• the appropriate chapter(s) of the Guidelines for the body system they are assessing.
• the National Acoustic Laboratories Report No. 118 January 1988 ‘Improved procedure for determining percentage loss of hearing’.

The Guidelines take precedence over AMA5.

Assessment of hearing impairment (hearing loss)

9.1 A worker may present for assessment of hearing loss for compensation purposes before having undergone all or any of the health investigations that generally occur before assessment of permanent impairment. For this reason, and to ensure that conditions other than ‘occupational hearing impairment’ are precluded, the medical assessment should be undertaken by an ear, nose and throat specialist or other appropriately qualified medical specialist. The medical assessment needs to be undertaken in accordance with the hearing impairment section of AMA5 Table 11-10 (pp 272–275). The medical specialist performing the assessment must examine the worker. The medical specialist’s assessment must be based on medical history and ear, nose and throat examination, evaluation of relevant audiological tests, and evaluation of other relevant investigations available to the medical assessor. Only medical specialists can sign medical reports.

9.2 Disregard AMA5 sections 11.1b and 11.2 (pp 246–55), but retain Section 11.1a, ‘Interpretation of symptoms and signs’ (p 246).

9.3 Some of the relevant tests are discussed in the AMA5 hearing impairment evaluation summary in AMA5 Table 11-10 (pp 272–75). The relevant row for the Guidelines is the one headed ‘hearing impairment’, with the exception of the last column, headed ‘degree of impairment’. The degree of impairment is determined according to the Guidelines.

9.4 The level of hearing impairment caused by non-work-related conditions is assessed by the medical specialist and considered when determining the level of work-related hearing impairment. While this requires medical judgement on the part of the examining medical specialist, any non-work-related deductions should be recorded in the report.

9.5 Disregard AMA5 tables 11-1, 11-2 and 11-3 (pp 247–50). For the purposes of the Guidelines, National Acoustic Laboratory (NAL) tables from the NAL Report No. 118, ‘Improved procedure for determining percentage loss of hearing’ (January 1988) are adopted as follows:

• Tables RB 500-4000 (pp 11–16)
• Tables RM 500-4000 (pp 18–23)
• Appendices 1 and 2 (pp 8–9)
• Appendices 5 and 6 (pp 24–26)
• Tables EB 4000–8000 (pp 28–30) (The extension tables)
• Table EM 4000–8000 (pp 32–34) (The extension tables)

Where an assessor uses the extension tables, they must provide an explanation of the worker’s ‘special requirement to be able to hear at frequencies above 4000 Hz’ (NAL Report No.118, p 6).

In the presence of significant conduction hearing loss, the extension tables do not apply.

AMA5 Table 11-3 is to be replaced by Table 9.1 at the end of this chapter.

Hearing impairment

9.6 Impairment of a worker’s hearing is determined according to evaluation of the individual’s binaural hearing impairment (BHI).

9.7 Permanent hearing impairment should be evaluated when the condition is stable. Prosthetic devices (that is, hearing aids) must not be worn during the evaluation of hearing sensitivity.

9.8 Hearing threshold level for pure tones is defined as the number of decibels above standard audiometric zero for a given frequency at which the listener’s threshold of hearing lies when tested in a suitable sound attenuated environment. It is the reading on the hearing level dial of an audiometer that is calibrated according to Australian Standard AS 2586 1983.

9.9 Evaluation of binaural hearing impairment is determined by using the tables in the 1988 NAL publication with allowance for presbyacusis according to the presbyacusis correction table, if applicable, in the same publication.

The binaural tables RB 500-4000 (NAL publication, pp 11–16) are to be used. The extension tables EB 4000- 8000 (NAL publication, pp 28–30) may be used when the worker has a ‘special requirement to be able to hear at frequencies above 4000 Hz’ (NAL publication, p 6). Where an assessor uses the extension tables, they must provide an explanation of the worker’s special requirement to be able to hear at frequencies above 4000 Hz. For the purposes of calculating binaural hearing impairment, the better and worse ear may vary as between frequencies.

Where it is necessary to use the monaural tables, the binaural hearing impairment (BHI) is determined by the
formula:

BHI = [4 x (better ear hearing loss)] + worse ear hearing loss ÷ 5

9.10 Presbyacusis correction (NAL publication, p 24) only applies to occupational hearing loss contracted by a gradual process (eg occupational noise-induced hearing loss and/or occupational solvent-induced hearing loss). Please note that when calculating by formula for presbyacusis correction (eg when the worker is older than 81), use the formula shown in Appendix 6, line 160 of the NAL publication (p 26), which uses the correct number of 1.79059. Note: there is a typographical error in Table P on p 25 of the NAL publication, where the number 1.79509 is incorrectly used.

9.11 Binaural hearing impairment and severe tinnitus: Up to 5 per cent may be added to the work-related binaural hearing impairment for severe tinnitus caused by a work-related injury:

• after presbyacusis correction, if applicable
• before determining whole person impairment (WPI).

Assessment of severe tinnitus is based on a medical specialist’s assessment.

9.12 Only hearing ear: A worker has an ‘only hearing ear’ if he or she has suffered a non-work related severe or profound sensorineural hearing loss in the other ear. If a worker suffers a work-related injury causing a hearing loss in the only hearing ear of x dB HL at a relevant frequency, the worker’s work-related binaural hearing impairment at that frequency is calculated from the binaural tables using x dB as the hearing threshold level in both ears. Deduction for presbyacusis, if applicable, and addition for severe tinnitus, is undertaken according to the Guidelines.

9.13 When necessary, binaural hearing impairment figures should be rounded to the nearest 0.1%. Rounding up should occur if equal to or greater than 0.05%, and rounding down should occur if equal to or less than 0.04%.

9.14 Table 9.1 in the Guidelines (below) is used to convert binaural hearing impairment, after deduction for presbyacusis if applicable and after addition for severe tinnitus, to WPI.

• The current level of binaural hearing impairment is established by the relevant specialist.
• Convert this to WPI using Table 9.1 in the Guidelines.
• Calculate the proportion of the current binaural hearing impairment that was accounted for by the earlier assessment and express it as a percentage of the current hearing impairment.
• The percentage of current hearing impairment that remains is the amount to be compensated.
• This needs to be expressed in terms of WPI for calculation of compensation entitlement.

Example:

• The current binaural hearing impairment is 8%.
• The WPI is 4%.
• The binaural hearing impairment for which compensation was paid previously is 6%, which is 75% of the current binaural hearing impairment of 8%.
• The remaining percentage, 25% is the percentage of WPI to be compensated.
• Twenty-five per cent of the WPI of 4% is 1% WPI.

9.16 AMA5 examples 11.1, 11.2 and 11.3 (pp 250–51) are replaced by examples 9.1–9.7, below, which were developed by the working party.

AMA4 Chapter 8 (p 209) applies to the assessment of permanent impairment of the visual system, subject to the modifications set out below. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

• the Introduction in the Guidelines
• chapters 1 and 2 of AMA5
• the appropriate chapter(s) of the Guidelines for the body system they are assessing
• the appropriate chapter(s) of AMA4 for the body system they are assessing.

The Guidelines take precedence over AMA4 and AMA5.

Introduction and approach to assessment

10.1 The visual system must be assessed by an ophthalmologist.

10.2 AMA4 Chapter 8 (pp 209–22) is adopted for the Guidelines, without significant change.

10.3  AMA4 is used rather than AMA5 for the assessment of permanent impairment of the visual system because:

• the equipment recommended for use in AMA5 is expensive and not owned by most privately practising ophthalmologists (eg the Goldman apparatus for measuring visual fields)
• the assessments recommended in AMA5 are considered too complex, raising a risk that resulting assessments may be of a lower standard than if the AMA4 method is used
• there is little emphasis on diplopia in AMA5, yet this is a relatively frequent problem
• many ophthalmologists are familiar with the Royal Australian College of Ophthalmologists’ impairment guide, which is similar to AMA4.

10.4 Impairment of vision should be measured with the injured worker wearing their prescribed corrective spectacles and/or contact lenses, if that was normal for the injured worker before the workplace injury. If, as a result of the workplace injury, the injured worker has been prescribed corrective spectacles and/or contact lenses for the first time, or different spectacles and/or contact lenses than those prescribed before injury, the difference should be accounted for in the assessment of permanent impairment.

10.5 The ophthalmologist should perform, or review, all tests necessary for the assessment of permanent impairment rather than relying on tests, or interpretations of tests, done by the orthoptist or optometrist.

10.6 An ophthalmologist should assess visual field impairment in all cases.

10.7 In AMA4 Section 8.5 ‘Other conditions’ (p 222), the reference to ‘additional 10% impairment’ means 10% WPI, not 10% impairment of the visual system.

AMA5 Chapter 14 is excluded and replaced by this chapter. Before undertaking an impairment assessment, users of the Guidelines must be familiar with (in this order):

• the Introduction in the Guidelines
• chapters 1 and 2 of AMA5
• the appropriate chapter(s) of the Guidelines for the body system they are assessing.

The Guidelines replace the psychiatric and psychological chapter in AMA5.

Introduction

11.1 This chapter lays out the method for assessing psychiatric impairment. The evaluation of impairment requires a medical examination.

11.2 Evaluation of psychiatric impairment is conducted by a psychiatrist who has undergone appropriate training in this assessment method.

11.3 Permanent impairment assessments for psychiatric and psychological disorders are only required where the primary injury is a psychological one. The psychiatrist needs to confirm that the psychiatric diagnosis is the injured worker’s primary diagnosis.

Diagnosis

11.4 The impairment rating must be based upon a psychiatric diagnosis (according to a recognised diagnostic system) and the report must specify the diagnostic criteria upon which the diagnosis is based. Impairment arising from any of the somatoform disorders (DSM IV TR, pp 485–511) are excluded from this chapter.

11.5 If pain is present as the result of an organic impairment, it should be assessed as part of the organic condition under the relevant table. This does not constitute part of the assessment of impairment relating to the psychiatric condition. The impairment ratings in the body organ system chapters in AMA5 make allowance for any accompanying pain.

11.6 It is expected that the psychiatrist will provide a rationale for the rating based on the injured worker’s psychiatric symptoms. The diagnosis is among the factors to be considered in assessing the severity and possible duration of the impairment, but is not the sole criterion to be used. Clinical assessment of the person may include information from the injured worker’s own description of his or her functioning and limitations, and from family members and others who may have knowledge of the person. Medical reports, feedback from treating professionals and the results of standardised tests – including appropriate psychometric testing performed by a qualified clinical psychologist and work evaluations – may provide useful information to assist with the assessment. Evaluation of impairment will need to take into account variations in the level of functioning over time. Percentage impairment refers to whole person impairment (WPI).

Permanent impairment

11.7 A psychiatric disorder is permanent if, in your clinical opinion, it is likely to continue indefinitely. Regard should be given to:

• the duration of impairment
• the likelihood of improvement in the injured worker’s condition
• whether the injured worker has undertaken reasonable rehabilitative treatment
• any other relevant matters.

Effects of treatment

11.8 Consider the effects of medication, treatment and rehabilitation to date. Is the condition stable? Is treatment likely to change? Are symptoms likely to improve? If the injured worker declines treatment, this should not affect the estimate of permanent impairment. The psychiatrist may make a comment in the report about the likely effect of treatment or the reasons for refusal of treatment.

Co-morbidity

11.9 Consider comorbid features (eg bi-polar disorder, personality disorder, substance abuse) and determine whether they are directly linked to the work-related injury, or whether they were pre-existing or unrelated conditions.

Pre-existing impairment

11.10 To measure the impairment caused by a work-related injury or incident, the psychiatrist must measure the proportion of WPI due to a pre-existing condition. Pre-existing impairment is calculated using the same method for calculating current impairment level. The assessing psychiatrist uses all available information to rate the injured worker’s pre-injury level of functioning in each of the areas of function. The percentage impairment is calculated using the aggregate score and median class score using the conversion table below. The injured worker’s current level of WPI% is then assessed, and the pre-existing WPI% is subtracted from their current level, to obtain the percentage of permanent impairment directly attributable to the work-related injury. If the percentage of pre-existing impairment cannot be assessed, the deduction is 1/10th of the assessed WPI.

Psychiatric impairment rating scale (PIRS)

11.11 Behavioural consequences of psychiatric disorder are assessed on six scales, each of which evaluates an area of functional impairment:

1. Self care and personal hygiene (Table 11.1) - Activities of daily living
2. Social and recreational activities (Table 11.2) - Activities of daily living
3. Travel (Table 11.3) - Activities of daily living
4. Social functioning (relationships) (Table 11.4)
5. Concentration, persistence and pace (Table 11.5)
6. Employability (Table 11.6).

11.12 Impairment in each area is rated using class descriptors. Classes range from 1 to 5, in accordance with severity. The standard form must be used when scoring the PIRS. The examples of activities are examples only. The assessing psychiatrist should take account of the person’s cultural background. Consider activities that are usual for the person’s age, sex and cultural norms.

Using the PIRS to measure impairment

11.13 Rating psychiatric impairment using the PIRS is a two-step procedure:

1. Determine the median class score.
2. Calculate the aggregate score.

Determining the median class score

11.14 Each area of function described in the PIRS is given an impairment rating which ranges from Class 1 to 5. The six scores are arranged in ascending order, using the standard form. The median is then calculated by averaging the two middle scores eg:

• Example A: 1, 2, 3, 3, 4, 5 Median Class = 3
• Example B: 1, 2, 2, 3, 3, 4 Median Class = 2.5 = 3*
• Example C: 1, 2, 3, 5, 5, 5 Median Class = 4

*If a score falls between two classes, it is rounded up to the next class. A median class score of 2.5 thus becomes 3.

11.15 The median class score method was chosen as it is not influenced by extremes. Each area of function is assessed separately. While impairment in one area is neither equivalent nor interchangeable with impairment in other areas, the median seems the fairest way to translate different impairments onto a linear scale.

Median class score and percentage impairment

11.16 Each median class score represents a range of impairment, as shown below:

• Class 1 = 0–3%
• Class 2 = 4–10%
• Class 3 = 11–30%
• Class 4 = 31–60%
• Class 5 = 61–100%

Calculation of the aggregate score

11.17  The aggregate score is used to determine an exact percentage of impairment within a particular median class range. The six class scores are added to give the aggregate score. Use of the conversion table to arrive at percentage impairment

11.18 The aggregate score is converted to a percentage score using the conversion Table 11.7, below.

11.19 The conversion table was developed to calculate the percentage impairment based on the aggregate and median scores.

11.20 The scores within the conversion table are spread in such a way to ensure that the final percentage rating is consistent with the measurement of permanent impairment percentages for other body systems.

Table 11.7 Conversion table

Conversion table — explanatory notes

Table 11.8: PIRS rating form

AMA5 Chapter 9 (p 191) applies to the assessment of permanent impairment of the haematopoietic system, subject to the modifications set out below. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

• the Introduction in the Guidelines
• chapters 1 and 2 of AMA5
• the appropriate chapter(s) of the Guidelines for the body system they are assessing
• the appropriate chapter(s) of AMA5 for the body system they are assessing.

The Guidelines take precedence over AMA5.

Introduction

12.1 AMA5 Chapter 9 (pp 191–210) provides guidelines on the method of assessing permanent impairment of the haematopoietic system. Overall, that chapter should be followed when conducting the assessment, with variations indicated below.

12.2 Impairment of end organ function due to haematopoietic disorder should be assessed separately, using the relevant chapter of the Guidelines. The percentage whole person impairment (WPI) due to end organ impairment should be combined with any percentage WPI due to haematopoietic disorder, using the combined values table in AMA5 (pp 604–06).

Anaemia

12.3 Table 12.1 (below) replaces AMA5 Table 9-2 (p 193).

12.4 The assessor should exercise clinical judgement in determining WPI, using the criteria in Table 12.1. For example, if comorbidities exist which preclude transfusion, the assessor may assign class 3 or class 4, on the understanding that transfusion would under other circumstances be indicated. Similarly, there may be some claimants with class 2 impairment who, because of comorbidity, may undergo transfusion.

12.5 Pre-transfusion haemoglobin levels in Table 12.1 are to be used as indications only. It is acknowledged that for some claimants, it would not be medically advisable to permit the claimant’s haemoglobin levels to be as low as indicated in the criteria of Table 12.1.

12.6 The assessor should indicate a percentage WPI, as well as the class.

Polycythaemia and myelofibrosis

12.7 The level of symptoms (as in Table 12.1) should be used as a guide for the assessor in cases where non-anaemic tissue iron deficiency results from venesection.

White blood cell diseases

12.8 In cases of functional asplenia, the assessor should assign 3% WPI. This should be combined with any other impairment rating, using the Combined Values Table in AMA5 (pp 604–06).

Haemorrhagic and platelet disorders

12.9 AMA5 Table 9-4 (p 203) is to be used as the basis for assessing haemorrhagic and platelet disorders.

12.10 For the purposes of the Guidelines, the criteria for inclusion in class 3 of AMA5 Table 9-4 (p 203) are:

• symptoms and signs of haemorrhagic and platelet abnormality
• requires continuous treatment
• interference with daily activities; requires occasional assistance.

12.11 For the purposes of the Guidelines, the criteria for inclusion in class 4 of AMA5 Table 9-4 (p 203) is:

• symptoms and signs of haemorrhagic and platelet abnormality
• requires continuous treatment
• difficulty performing daily activities; requires continuous care.

Thrombotic disorders

12.12 AMA5 Table 9-4 (p 203) is used as the basis for determining impairment due to thrombotic disorder.

AMA5 Chapter 10 (p 211) applies to the assessment of permanent impairment of the endocrine system, subject to the modifications set out below. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

• the Introduction in the Guidelines
• chapters 1 and 2 of AMA5
• the appropriate chapter(s) of the Guidelines for the body system they are assessing
• the appropriate chapter(s) of AMA5 for the body system they are assessing.

The Guidelines take precedence over AMA5.

Introduction

13.1 AMA5 Chapter 10 provides a useful summary of the methods for assessing permanent impairment arising from disorders of the endocrine system.

13.2 Refer to other chapters in AMA5 for related structural changes – the skin (eg pigmentation, in Chapter 8), the central and peripheral nervous system (eg memory, in Chapter 13), the urinary and reproductive system (eg infertility renal impairment, in Chapter 7), the digestive system (eg dyspepsia, in Chapter 6) and the cardiovascular system (in chapters 3 and 4) and visual system (Chapter 8 AMA4).

13.3 The clinical findings to support the impairment assessment are to be reported in the units recommended by the Royal College of Pathologists of Australia. (See Appendix 13.1).

13.4 Westergren erythrocyte sedimentation rate (WSR) is equivalent to ESR.

Adrenal cortex

13.5 AMA5 (p 222) first paragraph: disregard the last sentence, ‘They also affect inflammatory response, cell membrane permeability, and immunologic responses, and they play a role in the development and maintenance of secondary sexual characteristics’. Replace with: ‘Immunological and inflammatory responses are reduced by these hormones and they play a role in the development and maintenance of secondary sexual characteristics.’

13.6 AMA5 example 10-18 (pp 224–25): See reference to ESR (paragraph 13.4, above).

13.7 AMA5 example 10-20, regarding history (p 225): Instead of ‘hypnotic bladder’, read ‘hypotonic bladder’.

Diabetes mellitus

13.8 AMA5 (p 231): refer to the Australian Diabetes Association Guidelines with regard to levels of fasting glucose. (The position statement from the Australian Diabetes Society is reprinted in Appendix 13.2).

13.9 AMA5 (p 231): At the end of the second paragraph insert, ‘The goal of treatment is to maintain haemoglobin A1c within 1% of the normal range (4.0–6.3%)’.

Mammary glands

13.10 AMA5 example 10-45, regarding current symptoms (p 239): Disregard the last sentence, ‘Both bromocriptine and cabergoline cause nausea, precluding use of either drug’. Replace with: ‘Routine use of bromocriptine and cabergoline is normal in Australia. It is rare that nausea precludes their use’.

Criteria for rating permanent impairment due to metabolic bone disease

13.11 AMA5 (p 240): Impairment due to a metabolic bone disease itself is unlikely to be associated with a work injury and would usually represent a pre-existing condition.

13.12 Impairment from fracture, spinal collapse or other complications may arise as a result of a work injury associated with these underlying conditions (as noted in AMA5 Section 10.10c) and would be assessed using the other chapters indicated, with the exception of Chapter 18, on pain, which is excluded from the Guidelines.

Appendix 13.1: Interpretation of pathology tests

From the Manual of use and interpretation of pathology tests, 3rd edition. Reprinted with kind permission of the Royal College of Pathologists of Australasia.

AMA5 Chapter 8 (p 173) applies to the assessment of permanent impairment of the skin, subject to the modifications set out below. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

• the Introduction in the Guidelines
• chapters 1 and 2 of AMA5
• the appropriate chapter(s) of the Guidelines for the body system they are assessing
• the appropriate chapter(s) of AMA5 for the body system they are assessing.

The Guidelines take precedence over AMA5.

Introduction

14.1 AMA5 Chapter 8 (pp 173–90) refers to skin diseases generally rather than work related skin diseases alone. This chapter has been adopted for measuring impairment of the skin system, with the following variations.

14.2 Disfigurement, scars and skin grafts may be assessed as causing significant permanent impairment when the skin condition causes limitation in the performance of activities of daily living (ADL).

14.3 For cases of facial disfigurement, refer to Table 6.1 in Chapter 6 of in the Guidelines.

14.4 AMA5 Table 8-2 (p 178) provides the method of classification of impairment due to skin disorders. Three components – signs and symptoms of skin disorders, limitations in ADL and requirements for treatment – define five classes of permanent impairment. The assessing specialist should derive a specific percentage impairment within the range for the class that best describes the clinical status of the claimant.

14.5 The skin is regarded as a single organ and all non-facial scarring is measured together as one overall impairment, rather than assessing individual scars separately and combining the results.

14.6 A scar may be present and rated as 0% WPI.

Note that uncomplicated scars for standard surgical procedures do not, of themselves, rate an impairment.

14.7 The table for the evaluation of minor skin impairment (TEMSKI) (see Table 14.1 below) is an extension of Table 8-2 in AMA5. The TEMSKI divides class 1 of permanent impairment (0–9%) due to skin disorders into five categories of impairment. The TEMSKI may be used by trained assessors (who are not trained in the skin body system), for determining impairment from 0–4% in the class 1 category, that has been caused by minor scarring following surgery. Impairment greater than 4% must be assessed by a specialist who has undertaken the requisite training in the assessment of the skin body system.

14.8 The TEMSKI is to be used in accordance with the principle of ‘best fit’. The assessor must be satisfied that the criteria within the chosen category of impairment best reflect the skin disorder being assessed. If the skin disorder does not meet all of the criteria within the impairment category, the assessor must provide detailed reasons as to why this category has been chosen over other categories.

14.9 Where there is a range of values in the TEMSKI categories, the assessor should use clinical judgement to determine the exact impairment value.

14.10 The case examples provided in AMA5 Chapter 8 do not, in most cases, relate to permanent impairment that results from a work-related injury. The following NSW examples are provided for information.

14.11 Work-related case study examples 14.1–14.6 are included below, in addition to AMA5 examples 8.1–8.22 (pp 178–87).

Table 14.1: Table for the evaluation of minor skin impairment (TEMSKI)

This table uses the principle of 'best fit'. You should assess the impairment to the whole skin system against each criteria and then determine which impairment category best fits (or describes) the impairment. Refer to 14.8 regarding application of this table.

Examples

AMA5 chapters 3 and 4 (pp 23 and 65) apply to the assessment of permanent impairment of the cardiovascular system, subject to the modifications set out below. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

• the Introduction in the Guidelines
• chapters 1 and 2 of AMA5
• the appropriate chapter(s) of the Guidelines for the body system they are assessing
• the appropriate chapter(s) of AMA5 for the body system they are assessing.

The Guidelines take precedence over AMA5.

Introduction

15.1 The cardiovascular system is discussed in AMA5 chapters 3 (Heart and Aorta) and 4 (Systemic and Pulmonary Arteries) (pp 25–85). These chapters can be used to assess permanent impairment of the cardiovascular system with the following minor modifications.

15.2 It is noted that in these chapters there are wide ranges for the impairment values in each category. When conducting an assessment, assessors should use their clinical judgement to express a specific percentage within the range suggested.

Exercise stress testing

15.3 As with other investigations, it is not the role of an assessor to order exercise stress tests purely for the purpose of evaluating the extent of permanent impairment.

15.4 If exercise stress testing is available, then it is a useful piece of information in arriving at the overall percentage impairment.

15.5 If previous investigations are inadequate for a proper assessment to be made, the assessor should consider the value of proceeding with the evaluation of permanent impairment without adequate investigations and data (see Chapter 1 of the Guideline – ordering of additional investigations).

Permanent impairment – maximum medical improvement

15.6 As for all assessments, maximal medical improvement is considered to have occurred when the worker’s condition is well stabilised and unlikely to change substantially in the next year, with or without medical treatment.

Vascular diseases affecting the extremities

15.7 Note that in this section, AMA5 tables 4-4 and 4-5 (p 76) refer to percentage impairment of the upper or lower extremity. Therefore, an assessment of impairment concerning vascular impairment of the arm or leg requires that the percentages identified in these tables be converted to whole person impairment (WPI). The table for conversion of the upper extremity is AMA5 Table 16-3 (p 439), and the table for conversion of the lower extremity is AMA5 Table 17-3 (p 527).

Thoracic outlet syndrome

15.8 Impairment due to thoracic outlet syndrome is assessed according to AMA5 Chapter 16, relating to the upper extremities, and Chapter 2 of the Guidelines.

AMA5 Chapter 6 (p 117) applies to the management of permanent impairment of the digestive system. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

• the Introduction in the Guidelines
• chapters 1 and 2 of AMA5
• the appropriate chapter(s) of the Guidelines for the body system they are assessing.
• the appropriate chapter(s) of AMA5 for the body system they are assessing.

The Guidelines take precedence over AMA5.

Introduction

16.1 The digestive system is discussed in AMA5 Chapter 6 (pp 117–42). This chapter can be used to assess permanent impairment of the digestive system.

16.2 AMA5 Section 6.6, ‘Hernias’ (p 136): Occasionally in regard to inguinal hernias, there is damage to the ilioinguinal nerve following surgical repair. Where there is loss of sensation in the distribution of the ilio-inguinal nerve involving the upper anterior medial aspect of the thigh, a 1% WPI should be assessed as per Table 5.1 in Chapter 5 of the Guidelines. This assessment should not be made unless the symptoms have persisted for 12 months.

16.3 Where, following repair, there is severe dysaesthesia in the distribution of the ilio inguinal nerve, a maximum of 5% whole person impairment (WPI) may be assessed as per Table 5.1 in Chapter 5 of the Guidelines. This assessment should not be made unless the symptoms have persisted for 12 months.

16.4 Where, following repair of a hernia of the abdominal wall, there is residual persistent excessive induration at the site, which is associated with significant discomfort, this should be assessed as a class 1 herniation (AMA5 Table 6-9, p 136). This assessment should not be made unless symptoms have persisted for 12 months.

16.5 Impairments due to nerve injury and induration cannot be combined. The higher impairment should be chosen.

16.6 A person who has suffered more than one work-related hernia recurrence at the same site and who now has limitation of activities of daily living should be assessed as herniation class 1 (AMA5 Table 6-9, p 136).

16.7 A diagnosis of a hernia should not be made on the findings of an ultrasound examination alone. For the diagnosis of a hernia to be made there must be a palpable defect in the supporting structures of the abdominal wall and either a palpable lump or a history of a lump when straining.

16.8 A divarication of the rectus abdominus muscles in the upper abdomen is not a hernia, although the supporting structures have been weakened, they are still intact.

16.9 Effects of analgesics on the digestive tract:

• AMA5 Table 6-3 (p 121) Class 1 is to be amended to read ‘there are symptoms and signs of digestive tract disease’.
• Nonsteroidal anti-inflammatory agents, including Aspirin, taken for prolonged periods can cause symptoms in the upper digestive tract. In the absence of clinical signs or other objective evidence of upper digestive tract disease, anatomic loss or alteration a 0% WPI is to be assessed.
• Effects of analgesics on the lower digestive tract:
  • Constipation is a symptom, not a sign and is generally reversible. A WPI assessment of 0% applies to constipation.
  • Irritable bowel syndrome without objective evidence of colon or rectal disease is to be assessed at 0% WPI.
• Assessment of colorectal disease and anal disorders requires the report of a treating doctor or family doctor, which includes a proper physical examination with rectal examination if appropriate, and/or a full endoscopy report.
• Failure to provide such reports may result in a 0% WPI.

16.10 Splenectomy: Post-traumatic splenectomy or functional asplenia following abdominal trauma should be assessed as 3% WPI.

16.11 Abdominal adhesions: Intra-abdominal adhesions following trauma requiring further laparotomy should be assessed according to AMA5 Table 6-3 (p 121).

(exclude AMA5 Chapter 18)

17.1 The International Association for the Study of Pain (IASP) has defined pain as:

‘An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage’.

17.2 For chronic pain assessment using AMA5 and the Guidelines, exclude AMA5 Chapter 18, on pain (p 565–91).

17.3 The reasons for excluding chronic pain, as a separate condition from the Guidelines are:

• It is a subjective experience and is, therefore, open to exaggeration or fabrication in the compensation setting. Assessment depends on the credibility of the subject being assessed. In order to provide reliability,  applicants undergoing pain assessments require more than one examiner at different times, concordance with the established conditions, consistency over time, anatomical and physiological consistency, agreement between the examiners and exclusion of inappropriate illness behaviour.
• Pain cannot be measured and no objective assessment can be made.
• Tools to measure pain are based on self-reports and may be inherently unreliable.
• Some impairment ratings take symptoms into account and some of the ranges of impairment – eg whole person impairment (WPI) of the spine, may reflect the effect of the injury and pain on activities of daily living (ADL). This is not so for impairment assessment of the upper and lower limb, which is based on range of movement and diagnosis-based estimates, other than for peripheral nerve injury.

17.4 Where there is a peripheral nerve injury and there is sensory loss, some of the sensory nerve impairment categories permit pain to be included (AMA5 Table 16-10, categories 1-5, p 482).

17.5 AMA5 Section 17.2m, ‘Causalgia and complex regional pain syndrome (reflex sympathetic dystrophy)’ (p 553), should not be used. AMA5 Table 16-16 (p 496) has been replaced by Table 17.1 (below) in the Guidelines. Table 17.1 is used to determine if complex regional pain syndrome (CRPS) is a rateable diagnosis. It is important to exclude diagnoses that may mimic CRPS, such as disuse atrophy, unrecognised general medical problems, somatoform disorders and factitious disorder. Once the diagnosis is established, assess impairment as in AMA5.

_{1. Consequent to the enactment of the PIC Act the WIMWC Act is amended to omit references to ‘approved medical specialist’ and instead insert ‘medical assessor’.}

Permanent impairment coordinating committees

Working groups