Motor accident permanent impairment guidelines

Manual muscle strength testing

1.83 The Medical Research Council (MRC) grades for muscle strength are universally accepted. They are not linear in their application, but ordinal. The descriptions in Table 38 (page 77, AMA4 Guides) are to be used. The results of electrodiagnostic methods and tests are not to be considered in the evaluation of muscle testing, which is performed manually. Table 39 (page 77, AMA4 Guides) is to be used for this method of evaluation.

Range of motion

1.84 Although range of motion (pages 77–78, AMA4 Guides) appears to be a suitable method for evaluating impairment, it can be subject to variation because of pain during motion at different times of examination and/or a possible lack of cooperation by the injured person being assessed. Range of motion is assessed as follows:

1.84.1 A goniometer should be used where clinically indicated.

1.84.2 Passive range of motion may form part of the clinical examination to ascertain clinical status of the joint, but impairment should only be calculated using active range of motion measurements.

1.84.3 If the medical assessor is not satisfied that the results of a measurement are reliable, active range of motion should be measured with at least three consistent repetitions.

1.84.4 If there is inconsistency in range of motion, then it should not be used as a valid parameter of impairment evaluation. Refer to clause 1.40 of these Guidelines.

1.84.5 If range of motion measurements at examination cannot be used as a valid parameter of impairment evaluation, the medical assessor should then use discretion in considering what weight to give other evidence available to determine if an impairment is present.

1.85 Tables 40 to 45 (page 78, AMA4 Guides) are used to assess range of motion in the lower extremities. Where there is loss of motion in more than one direction/axis of the same joint, only the most severe deficit is rated – the ratings for each motion deficit are not added or combined. However, motion deficits arising from separate tables can be combined.

Ankylosis

1.86 For the assessment of impairment when a joint is ankylosed (pages 79–82, AMA4 Guides), the calculation to be applied is to select the impairment if the joint is ankylosed in optimum position and then, if not ankylosed in the optimum position (Table 6.2), by adding (not combining) the values of WPI using Tables 46–61 (pages 79–82, AMA4 Guides). Note: The example listed under the heading ‘Hip’ on page 79 of the AMA4 Guides is incorrect.

1.87 Note that the WPI from ankylosis of a joint, or joints, in the lower limb cannot exceed 40% WPI or 100% lower limb impairment. If this figure is exceeded when lower limb impairments are combined, then only 40% can be accepted as the maximum WPI.

Arthritis

1.88 Impairment due to arthritis (pages 82–83, AMA4 Guides) can be assessed by measuring the distance between the subchondral bone ends (joint space) if radiography is performed in defined positions. It indicates the thickness of articular cartilage. No notice is to be taken of other diagnostic features of arthritis such as osteophytes or cystic changes in the bone.

1.89 Hip radiography can be done in any position of the hip, but specified positions for the knee and ankle (page 82, AMA4 Guides) must be achieved by the radiographer.

1.90 Table 62 (page 83, AMA4 Guides) indicates the impairment assessment for arthritis based on articular cartilage thickness.

1.91 If arthritis is used as the basis for impairment assessment in this way, then the rating cannot be combined with gait derangement, muscle atrophy, muscle strength or range of movement assessments. It can be combined with a diagnosis-based estimate (Table 5).

1.92 When interpreting Table 62 (page 83, AMA4 Guides), if the articular cartilage interval is not a whole number, round to the higher impairment figure.

Amputation

1.93 Where there has been amputation of part of a lower extremity Table 63 applies (page 83, AMA4 Guides). The references to 3 inches below knee amputation should be converted to 7.5 centimetres.

Diagnosis-based estimates (lower extremity)

1.94 Section 3.2i (pages 84–88, AMA4 Guides) lists a number of conditions that fit a category of diagnosis-based estimates. They are listed in Table 64 (pages 85–86, AMA4 Guides). It is essential to read the footnotes.

1.95 It is possible to combine impairments from Table 64 for diagnosis-based estimates with other injuries (for example, nerve injury) using the ‘Combined values’ chart (pages 322–324, AMA4 Guides).

1.96 Pelvic fractures must be assessed using Section 3.4 (page 131, AMA4 Guides). Fractures of the acetabulum should be assessed using Table 64 (pages 85‑86, AMA4 Guides).

1.97 Residual signs must be present at examination and may include anatomically plausible tenderness, clinically obvious asymmetry, unilateral limitation of hip joint range of motion not associated with fractured acetabulum and/or clear evidence of malalignment.

1.98 Where both collateral and cruciate ligament laxity of mild severity is present, these must be assessed separately as 3% WPI for each ligament and then combined, resulting in a total of 6% WPI.

1.99 Rotational deformity following tibial shaft fracture must be assessed analogously to Table 64 ‘Tibial shaft fracture, malalignment of’ (page 85, AMA4 Guides).

1.100 To avoid the risk of double assessment, if avascular necrosis of the talus is used as the basis for assessment, it cannot be combined with intra-articular fracture of the ankle with displacement or intra-articular fracture of the hind foot with displacement in Table 64, column 1 (page 86, AMA4 Guides).

1.101 Tables 65 and 66 (pages 87–88, AMA4 Guides) use a different method of assessment. A point score system is applied, and then the total of points calculated for the hip or knee joint respectively is converted to an impairment rating from Table 64. Tables 65 and 66 refer to the hip and knee joint replacement respectively. Note that while all the points are added in Table 65, some points are deducted when Table 66 is used.

1.102 In Table 65 references to distance walked under ‘b. Function’, six blocks should be construed as being 600 metres, and three blocks being 300 metres.

Skin loss (lower extremity)

1.103 Skin loss can only be included in the calculation of impairment if it is in certain sites and meets the criteria listed in Table 67 (page 88, AMA4 Guides). Scarring otherwise in the lower extremity must be assessed with reference to ‘Other body systems’ within this part of the Motor Accident Guidelines.

Impairment of the lower extremity due to peripheral nerve injury

1.104 Peripheral nerve injury should be assessed by reference to Section 3.2k (pages 88–89, AMA4 Guides). Separate impairments for the motor, sensory and dysaesthetic components of nerve dysfunction in Table 68 (page 89, AMA4 Guides) are combined.

1.105 The posterior tibial nerve is not included in Table 68, but its contribution can be calculated by subtracting common peroneal nerves rating from sciatic nerve rating as shown in Table 6.3 (below). The values in brackets are lower extremity impairment values.

1.106 Peripheral nerve injury impairments can be combined with other impairments, but not those for muscle strength, gait derangement, muscle atrophy and CRPS, as shown in Table 5. When using Table 68, refer to Tables 11a and 12a (pages 48–49, AMA4 Guides) and clauses 1.58, 1.59 and 1.60 of these Guidelines.

Impairment of the lower extremity due to CRPS

1.107 The Section ‘Causalgia and reflex sympathetic dystrophy’ (page 89, AMA4 Guides) must not be used. These conditions have been better defined since the AMA4 Guides were published. The current terminology is CRPS type I (referring to what was termed reflex sympathetic dystrophy) and CRPS type II (referring to what was termed causalgia).

1.108 When complex CRPS occurs in the lower extremity it must be evaluated as for the upper extremity using clauses 1.61–1.64 within this part of the Motor Accident Guidelines.

Impairment of the lower extremity due to peripheral vascular disease

1.109 Lower extremity impairment due to peripheral vascular disease is evaluated using Table 69 (page 89, AMA4 Guides). Table 14 (page 198, AMA4 Guides) must not be used. In Table 69, there is a range of lower extremity impairments, not WPI, within each of the classes 1 to 5. Where there is a range of impairment percentages listed, the medical assessor must nominate an impairment percentage based on the complete clinical circumstances revealed during the examination and provide reasons.

1.110 Lower extremity impairment values must be converted to WPI using
Table 6.4.

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Spine

Introduction

1.111 The spine is discussed in Section 3.3 of Chapter 3 in the AMA4 Guides (pages 94–138). That chapter presents several methods of assessing impairments of the spine. Only the diagnosis-related estimate (DRE) method is to be used for evaluating impairment of the spine, as modified by this Part of the Motor Accident Guidelines. The AMA4 Guides use the term injury modelfor this method.

1.112 The injury model relies especially on evidence of neurological deficits and uncommon, adverse structural changes, such as fractures and dislocations. Under this model, DREs are differentiated according to clinical findings that are verifiable using standard medical procedures.

1.113 The assessment of spinal impairment is made at the time the injured person is examined. If surgery has been performed, then the effect of the surgery, as well as the structural inclusions, must be taken into consideration when assessing impairment. Refer also to clause 1.20 in these Guidelines.

1.114 Medical assessors must consider whether any pre-existing spinal condition or surgery is related to the motor accident, is symptomatic and whether this would result in any or total apportionment. Where a pre-existing spinal condition, or spinal surgery, is unrelated to the injury from the relevant motor accident, the medical assessor should rely on clause 1.33.

1.115 The AMA4 Guides use the terms cervicothoracic, thoracolumbar and lumbosacral for the three spine regions. These terms relate to the cervical, thoracic and lumbar regions respectively.

Assessment of the spine

1.116 The range of motion (ROM) model and Table 75 are not to be used for spinal impairment evaluation (pages 112–130, AMA4 Guides).

1.117 The medical assessor may consider Table 7 (below) to establish the appropriate category for the spine impairment. Its principal difference from Table 70 (page 108, AMA4 Guides) is the removal of the term motion segment integrity wherever it appears (see clause 1.123).

1.118 The evaluation must not include any allowance for predicted long-term change. For example, a spinal stenosis syndrome after vertebral fracture or increased back pain due to osteoarthritis of synovial joints after intervertebral disc injury must not be factored in to the impairment evaluation.

1.119 All impairments in relation to the spine should be calculated in terms of WPI and assessed in accordance with clauses 1.1 to 1.46 within these Motor Accident Guidelines and Chapter 3.3 of AMA4 Guides.

1.120 The assessment should include a comprehensive accurate history, a review of all relevant records available at the assessment, a comprehensive description of the individual’s current symptoms, a careful and thorough physical examination and all findings of relevant diagnostic 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 medical assessor should record whether diagnostic tests and radiographs were seen or whether they relied on reports.

1.121 While imaging and other studies may assist medical assessors in making a diagnosis, it is important to note that the presence of a morphological variation from what is called normal in an imaging study does not make the diagnosis. Several reports indicate that approximately 30% of people who have never had back pain will have an imaging study that can be interpreted as positive for a herniated disc, and 50% or more will have bulging discs. Further, the prevalence of degenerative changes, bulges and herniations increases with advancing age. To be of diagnostic value, imaging findings must be concordant with clinical symptoms and signs, and the history of injury. In other words, an imaging test is useful to confirm a diagnosis, but an imaging result alone is insufficient to qualify for a DRE category.

1.122 The medical assessor must include in the report a description of how the impairment rating was calculated, with reference to the relevant tables and/or figures used.

Specific interpretation of the AMA4 Guides

Loss of motion segment integrity

1.123 The Section ‘Loss of motion segment integrity’ (pages 98–99, AMA4 Guides) and all subsequent references to it must not be applied, as the injury model (DRE method) covers all relevant conditions.

Definitions of clinical findings used to place an individual in a DRE category

1.124 Definitions of clinical findings, which are used to place an individual in a DRE category are provided in Table 8 (below). A definition of a muscle spasm has been included; however, it is not a clinical finding used to place an individual in a DRE category.

Diagnosis-related estimates model

1.125 To determine the correct diagnosis-related estimates (DRE) category, the medical assessor may start with Table 7 in these Guidelines, and use this table in conjunction with the DRE descriptors (pages 102–107, AMA4 Guides), as clarified by the definitions in Table 8 (above), with the following amendments to pages 102–107 of the AMA4 Guides:

1.125.1 or history of guarding is deleted from DRE category I for the lumbosacral spine (page 102) and DRE category I for the cervicothoracic spine (page 103)

1.125.2 no significant…roentgenograms is deleted from DRE category I for the lumbosacral spine (page 102) and DRE category I for the cervicothoracic spine (page 103) and DRE categoy I for the thoracolumbar (p106)

1.125.3 documented or as it relates to muscle guarding is deleted from DRE category I for the thoracolumbar spine (page 106)

1.125.4 replace that has been observed and documented by a physician with that has been observed and documented by the medical assessor in DRE category II for the lumbosacral spine (page 102)

1.125.5 replace observed by a physician with observed by the medical assessor in the descriptors for DRE category II for the cervicothoracic spine (page 104) and thoracolumbar spine (page 106)

1.125.6 replace or displacement with with displacement in the descriptors for DRE category II for the thoracolumbar spine (page 106).

1.126 If unable to distinguish between two DRE categories, the higher of those two categories must apply. The inability to differentiate must be noted and explained in the medical assessor’s report.

1.127 Table 71 (page 109, AMA4 Guides) is not to be used. The definitions of clinical findings in Table 8 should be the criteria by which a diagnosis and allocation of a DRE category are made.

Applying the DRE method

1.128 Section 3.3f ‘Specific procedures and directions’ (page 101, AMA4 Guides) indicates the steps that should be followed. Table 7 in these Guidelines is a simplified version of that section, and must be interpreted in conjunction with the amendments listed in clause 1.125 (above).

1.129 DRE I applies when the injured person has symptoms but there are no objective clinical findings by the medical assessor. DRE II applies when there are clinical findings made by the medical assessor, as described in the Sections ‘Description and Verification’ (pages 102–107, AMA4 Guides) with the amendments in clause 1.125, for each of the three regions of the spine. Note that symmetric loss of movement is not dysmetria and does not constitute an objective clinical finding.

1.130 When allocating the injured person to a DRE category, the medical assessor must reference the relevant differentiators and/or structural inclusions.

1.131 Separate injuries to different regions of the spine must be combined.

1.132 Multiple impairments within one spinal region must not be combined. The highest DRE category within each region must be chosen.

Loss of structural integrity

1.133 The AMA4 Guides (page 99) use the term structural inclusionsto define certain spine fracture patterns that may lead to significant impairment and yet not demonstrate any of the findings involving differentiators. Some fracture patterns are clearly described in the examples of DRE categories in Sections 3.3g, 3.3h and 3.3i. They are not the only types of injury in which there is a loss of structural integrity of the spine. In addition to potentially unstable vertebral body fractures, loss of structural integrity can occur by purely soft tissue flexion-distraction injuries.

Spondylolysis and spondylolisthesis

1.134 Spondylolysis and spondylolisthesis are conditions that are often asymptomatic and are present in 5–6% of the population. In assessing their relevance the degree of slip (anteroposterior translation) is a measure of the grade of spondylolisthesis and not in itself evidence of loss of structural integrity. To assess an injured person as having symptomatic spondylolysis or spondylolisthesis requires a clinical assessment as to the nature and pattern of the injury, the injured person’s symptoms and the medical assessor’s findings on clinical examination. Table 8 can be used to allocate spondylolysis or spondylolisthesis to categories I–V depending on the descriptor’s clinical findings in the appropriate DRE. The injured person’s DRE must fit the description of clinical findings described in Table 8.

1.135 Medical assessors should be aware that acute traumatic spondylolisthesis is a rare event.

Sexual functioning

1.136 Sexual dysfunction should only be assessed as an impairment related to spinal injury where there is other objective evidence of spinal cord, cauda equina or bilateral nerve root dysfunction (Table 19, page 149, AMA4 Guides). There is no additional impairment rating for sexual dysfunction in the absence of objective neurological impairment.

1.137 Chapter 11 ‘The urinary and reproductive systems’ of the AMA4 Guides should only be used to assess impairment for impotence where there has been a direct injury to the urinary tract. If this occurs the impairment for impotence must be combined with any spine-related WPI. An example is provided in the AMA4 Guides (page 257) where there is a fracture and dissociation of the symphysis pubis and a traumatic disruption of the urethra.

Radiculopathy

1.138 Radiculopathyis the impairment caused by dysfunction of a spinal nerve root or nerve roots. To conclude that a radiculopathy is present two or more of the following signs should be found:

1.138.1 loss or asymmetry of reflexes (see the definitions of clinical findings in Table 8 in these Guidelines)

1.138.2 positive sciatic nerve root tension signs (see the definitions of clinical findings in Table 8 in these Guidelines)

1.138.3 muscle atrophy and/or decreased limb circumference (see the definitions of clinical findings in Table 8 in these Guidelines)

1.138.4 muscle weakness that is anatomically localised to an appropriate spinal nerve root distribution

1.138.5 reproducible sensory loss that is anatomically localised to an appropriate spinal nerve root distribution.

1.139 Spinal injury causing sensory loss at C2 or C3 must be assessed by firstly using Table 23 (page 152) of the AMA4 Guides, rather than classifying the injury as DRE cervicothoracic category III (radiculopathy). The value must then be combined with the DRE rating for the cervical vertebral injury.

1.140 Note that complaints of pain or sensory features that follow anatomical pathways but cannot be verified by neurological findings do not by themselves constitute radiculopathy. They are described as non-verifiable radicular complaints in the definitions of clinical findings (Table 8 in these Guidelines).

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

1.142 Electrodiagnostic tests are rarely necessary investigations and a decision about the presence of radiculopathy can generally be made on clinical grounds. The diagnosis of radiculopathy should not be made solely from electrodiagnostic tests.

Multilevel structural compromise

1.143 Multilevel structural compromise (Table 70, page 108, AMA4 Guides) refers to those DREs that are in categories IV and V. It is constituted by structural inclusion, which by definition (page 99, AMA4 Guides) is related to spine fracture patterns and is different from the differentiators and clinical findings in Table 8.

1.1424 Multilevel structural compromise is to be interpreted as fractures of more than one vertebra. To provide consistency of interpretation of the meaning of multiple vertebral fractures, the definition of a vertebral fracture includes any fracture of the vertebral body or of the posterior elements forming the ring of the spinal canal (the pedicle or lamina). It does not include fractures of transverse processes or spinous processes, even at multiple levels (see also clause 1.149 in these Guidelines).

1.145 Multilevel structural compromise also includes spinal fusion and intervertebral disc replacement.

1.146 Multilevel structural compromise or spinal fusion across regions is assessed as if it is in one region. The region giving the highest impairment value must be chosen. A fusion of L5 and S1 is considered to be an intervertebral fusion.

1.147 A vertebroplasty should be assessed on the basis of the fracture for which it was performed.

1.148 Compression fracture: The preferred method of assessing the amount of compression is to use a lateral X-ray of the spinal region with the beam parallel to the disc spaces. If this is not available, a CT scan can be used. Caution should be used in measuring small images as the error rate will be significant unless the medical assessor has the ability to magnify the images electronically. Medical assessors should not rely on the estimated percentage compression reported on the radiology report, but undertake their own measurements to establish an accurate percentage using the following method:

1.148.1 The area of maximum compression is measured in the vertebra with the compression fracture.

1.148.2 The same area of the vertebrae directly above and below the affected vertebra is measured and an average obtained. The measurement from the compressed vertebra is then subtracted from the average of the two adjacent vertebrae. The resulting figure is divided by the average of the two unaffected vertebrae and turned into a percentage.

1.148.3 If there are not two adjacent normal vertebrae, then the next vertebra that is normal and adjacent (above or below the affected vertebra) is used.

The calculations must be documented in the impairment evaluation report.

1.149 Fractures of transverse or spinous processes (one or more) with displacement within a spinal region are assessed as DRE category II because they do not disrupt the spinal canal (pages 102, 104, 106, AMA4 Guides) and they do not cause multilevel structural compromise.

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

1.151 In the application of Table 7 regarding multilevel structural compromise:

1.151.1 multiple vertebral fractures without radiculopathy are classed as category IV

1.151.2 multiple vertebral fractures with radiculopathy are classed as category V.

Spinal cord injury

1.152 The assessment of spinal cord injury is covered in clause 1.161 in these Guidelines.

1.153 Cauda equina syndrome: In the AMA4 Guides this term does not have its usual medical meaning. For the purposes of the AMA4 Guides an injured person with cauda equina syndrome has objectively demonstrated permanent partial loss of lower extremity function bilaterally. This syndrome may have associated objectively demonstrated bowel or bladder impairment.

Pelvic fractures

1.154 Pelvic fractures must be assessed using Section 3.4 (page 131, AMA4 Guides). Fractures of the acetabulum must be assessed using Table 64 (pages 85–86, AMA4 Guides).

1.155 Multiple fractures of the pelvis must be assessed separately and then combined.

Nervous system

Introduction

1.156 Chapter 4 (pages 139–152, AMA4 Guides) provides guidance on methods of assessing permanent impairment involving the central nervous system. Elements of the assessment of permanent impairment involving the peripheral nervous system can be found in relevant parts of the ‘Upper extremity’, ‘Lower extremity’ and ‘Spine’ sections.

1.157 Chapter 4 is logically structured and consistent with the usual sequence of examining the nervous system. Cortical functions are discussed first, followed by the cranial nerves, the brain stem, the spinal cord and the peripheral nervous system.

1.158 Spinal cord injuries (SCI) must be assessed using the ‘Nervous system’ and ‘Musculoskeletal system’ chapters of the AMA4 Guides and these Guidelines. See clause 1.161.

1.159 The relevant parts of the ‘Upper extremity’, ‘Lower extremity’ and ‘Spine’ chapters of the AMA4 Guides must be used to evaluate impairments of the peripheral nervous system.

Assessment of the nervous system

1.160 The introduction to Chapter 4 ‘Nervous system’ in the AMA4 Guides is ambiguous in its statement about combining nervous system impairments. The medical assessor must consider the categories of:

1.160.1 aphasia or communication disorders

1.160.2 mental status and integrative functioning abnormalities

1.160.3 emotional and behavioural disturbances

1.160.4 disturbances of consciousness and awareness (permanent and episodic).

The medical assessor must select the highest rating from categories 1 to 4. This rating can then be combined with ratings of other nervous system impairments or from other body regions.

1.161 A different approach is taken in assessing spinal cord impairment (Section 4.3, pages 147–148, AMA4 Guides). In this case impairments due to this pathology can be combined using the ‘Combined values’ chart (pages 322–324, AMA4 Guides). It should be noted that Section 4.3 ‘Spinal cord’ must be used for motor or sensory impairments caused by a central nervous system lesion. Impairment evaluation of spinal cord injuries should be combined with the associated DRE I–V from Section 3.3 in the ‘Musculoskeletal system’ Chapter (pages 101–107, AMA4 Guides). This section covers hemiplegia due to cortical injury as well as SCI.

1.162 Headache or other pain potentially arising from the nervous system, including migraine, is assessed as part of the impairment related to a specific structure. The AMA4 Guides state that the impairment percentages shown in the chapters of the AMA4 Guides make allowance for the pain that may accompany the impairing condition.

1.163 The ‘Nervous system’ Chapter of the AMA4 Guides lists many impairments where the range for the associated WPI is from 0% to 9% or 0% to 14%. Where there is a range of impairment percentages listed, the medical assessor must nominate an impairment percentage based on the complete clinical circumstances revealed during the examination and provide reasons.

Specific interpretation of the AMA4 Guides

The central nervous system – cerebrum or forebrain

1.164 For an assessment of mental status impairment and emotional and behavioural impairment there should be:

1.164.1 evidence of a significant impact to the head or a cerebral insult, or that the motor accident involved a high-velocity vehicle impact, and

1.164.2 one or more significant, medically verified abnormalities such as an abnormal initial post-injury Glasgow Coma Scale score, or post‑traumatic amnesia, or brain imaging abnormality.

1.165 The results of psychometric testing, if available, must be taken into consideration.

1.166 Assessment of disturbances of mental status and integrative functioning: Table 9 in these Guidelines – the clinical dementia rating (CDR), which combines cognitive skills and function – must be used for assessing disturbances of mental status and integrative functioning.

1.167 When using the CDR the injured person’s cognitive function for each category should be scored independently. The maximum CDR score is 3. Memory is considered the primary category; the other categories are secondary. If at least three secondary categories are given the same numeric score as memory then the CDR = M. If three or more secondary categories are given a score greater or less than the memory score, CDR = the score of the majority of secondary categories unless three secondary categories are scored less than M and two secondary categories are scored greater than M. In this case, then the CDR = M. Similarly if two secondary categories are greater than M, two are less than M and one is the same as M, CDR = M.

1.168 In Table 9, ‘Personal care’ (PC) for the level of impairment is the same for a CDR score of 0 and a CDR score of 0.5, being fully capable of self-care. In order to differentiate between a personal care CDR score of 0 and 0.5, a rating that best fits with the pattern of the majority of other categories must be allocated. For example, when the personal care rating is fully capable of self‑care and at least three other components of the CDR are scored at 0.5 or higher, the PC must be scored at 0.5. If three or more ratings are less than 0.5 then a rating of 0 must be assigned. Reasons to support all ratings allocated must be provided.

1.169 Corresponding impairment ratings for CDR scores are listed in Table 10 in these Guidelines.

1.170 Emotional and behavioural disturbances assessment: Table 3 (page 142, AMA4 Guides) must be used to assess emotional or behavioural disturbances.

1.171 Sleep and arousal disorders assessment: Table 6 (page 143, AMA4 Guides) must be used to assess sleep and arousal disorders. The assessment is based on the clinical assessment normally done for clinically significant disorders of this type.

1.172 Visual impairment assessment: An ophthalmologist must assess all impairments of visual acuity, visual fields or extra-ocular movements (page 144, AMA4 Guides).

1.173 Trigeminal nerve assessment: Sensory impairments of the trigeminal nerve must be assessed with reference to Table 9 (page 145, AMA4 Guides). The words or sensory disturbance are added to the table after the words neuralgic pain in each instance. Impairment percentages for the three divisions of the trigeminal nerve must be apportioned with extra weighting for the first division (for example, division 1 – 40%, and division 2 and 3 – 30% each). If present, motor loss for the trigeminal nerve must be assessed in terms of its impact on mastication and deglutition (page 231, AMA4 Guides).

1.174 As per clause 1.189, regarding bilateral total facial paralysis in Table 4 (page 230, AMA4 Guides) total means all branches of the facial nerve.

1.175 Sexual functioning assessment: Sexual dysfunction is assessed as an impairment only if there is an associated objective neurological impairment (page 149, AMA4 Guides). This is consistent with clauses 1.136 and 1.137 in these Guidelines.

1.176 Olfaction and taste assessment: The assessment of olfaction and taste is covered in clauses 1.192 and 1.193 in these Guidelines.

Download a PDF of this table in full.

Download a PDF of this table in full.

Ear, nose and throat, and related structures

Introduction

1.177 Chapter 9 of the AMA4 Guides (pages 223–234) provides guidance on methods of assessing permanent impairment involving the ear, nose and throat, and related structures, including the face.

1.178 Chapter 9 discusses the ear, hearing, equilibrium, the face, respiratory (air passage) obstruction, mastication and deglutition, olfaction and taste, and speech. There is potential overlap with other chapters, particularly the nervous system, in these areas.

Assessment of ear, nose and throat, and related structures

1.179 To assess impairment of the ear, nose and throat, and related structures, the injured person must be assessed by the medical assessor. While the assessment may be based principally on the results of audiological or other investigations, the complete clinical picture must be elaborated through direct consultation with the injured person by the medical assessor.

Specific interpretation of the AMA4 Guides

Ear and hearing

1.180 Ear and hearing (pages 223–224, AMA4 Guides): Tinnitus is only assessable in the presence of hearing loss, and both must be caused by the motor accident. An impairment of up to 5% can be added, not combined, to the percentage binaural hearing impairment before converting to WPI hearing loss if tinnitus is permanent and severe.

Hearing impairment

1.181 Hearing impairment (pages 224-228, AMA4 Guides): Sections 9.1a and 9.1b of the AMA4 Guides are replaced with the following section.

1.182 Impairment of an injured person’s hearing is determined according to evaluation of the individual’s binaural hearing impairment.

1.183 Hearing impairment must be evaluated when the impairment is permanent. Prosthetic devices (i.e. hearing aids) must not be used during evaluation of hearing sensitivity.

1.184 Hearing threshold level for pure tones is defined as the number of decibels above a standard audiometric zero level 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 calibrated according to current Australian standards.

1.185 Binaural hearing impairment is determined by using the 1988 National Acoustics Laboratory tables ‘Improved procedure for determining percentage loss of hearing’, with allowance for presbyacusis according to the presbyacusis correction table in the same publication (NAL Report No. 118, National Acoustics Laboratory, Commonwealth of Australia, 1988).

1.186 Table 3 (page 228, AMA4 Guides) is used to convert binaural hearing impairment to impairment of the whole person. For example, a person aged 50 with a total unilateral hearing loss in the right ear and no hearing loss in the left ear has 17% binaural hearing impairment less 0% presbyacusis correction, which is equivalent to 6% WPI.

Equilibrium

1.187 Assessment of impairment due to disorders of equilibrium (pages 228–229, AMA4 Guides) is dependent on objective findings of vestibular dysfunction. Such data must be available to the medical assessor.

1.188 There is an error in the description of classes 3, 4 and 5 in ‘Criteria of vestibular impairment’ (page 229, AMA4 Guides). Class 3 of impairment of vestibular function is associated with a WPI of 11% to 30%. Class 4 is 31% to 60% and class 5, 61% to 95%.

Face

1.189 Facial scarring and disfigurement are assessed separately to scarring elsewhere on the body. This scarring is combined with any other assessment of scarring and/or other permanent impairment assessments. In Table 4 (page 230, AMA4 Guides), total means all branches of the facial nerve.

1.190 Loss of the entire outer ear is 11% WPI.

1.191 The assessment of permanent impairment involving scarring of the face may be undertaken using Chapter 13 ‘The skin’ (pages 279–280, AMA4 Guides) and/or Section 9.2 ‘The face’ (pages 229–230, AMA4 Guides).

Olfaction and taste

1.192 There is a discrepancy in the AMA4 Guides in the treatment of olfaction and taste between the ‘Nervous system’ Chapter (pages 144, 146) and the ‘ENT’ Chapter (pages 231–232). To resolve this difference, the medical assessor may assign a value of WPI from 1% to 5% for loss of sense of taste and a value of WPI from 1% to 5% for loss of sense of olfaction. Where there is a range of impairment percentages listed, the medical assessor must nominate an impairment percentage based on the complete clinical circumstances revealed during the examination and provide reasons.

1.193 However, the very rare case of total permanent loss of taste and olfaction is deemed in these Guidelines to constitute greater than 10% permanent impairment.

Teeth

1.194 An impairment assessment for loss of teeth must be done with the injured person wearing their dental prosthesis if this was normal for the injured person before the accident. If, as a result of the motor accident, the injured person required a removable dental prosthesis for the first time, or a different dental prosthesis, the difference should be accounted for in the assessment of permanent impairment.

1.195 Damage to the teeth can only be assessed when there is a permanent impact on mastication and deglutition (page 231, AMA4 Guides) and/or loss of structural integrity of the face (pages 229–230, AMA4 Guides).

1.196 Where loss of structural integrity occurs as a result of a dental injury, the injury must be assessed for a loss of functional capacity (mastication) and a loss of structural integrity (cosmetic deformity) and any impairment combined.

1.197 When using Table 6 ‘Relationship of dietary restrictions to permanent impairment’ (page 231, AMA4 Guides) the first category is to be 0–19%, not 5–19%.

1.198 In some cases, it will be necessary to access current dental X-rays to assess permanent impairment.

Respiration

1.199 When Table 5 (page 231, AMA4 Guides) is used for the evaluation of air passage defects, these Guidelines allow 0–5% WPI where there is significant difficulty in breathing through the nose and examination reveals significant partial obstruction of the right and/or left nasal cavity or nasopharynx, or significant septal perforation.

Speech

1.200 When Table 7 ‘Speech impairment criteria’ (page 233, AMA4 Guides) is used, the percentage from the table must be converted to WPI using Table 9 (page 234, AMA4 Guides).

Mental and behavioural disorders

Introduction

1.201 Psychiatric disorders have complex effects on the individual, and impairment must be assessed by a psychiatrist.

1.202 The AMA4 Guides do not give percentages of psychiatric impairment in Chapter 14 (pages 291–302), which deals with mental and behavioural disorders. Medically determinable impairments in thinking, affect, intelligence, perception, judgement and behaviour are difficult to translate into functional limitations.

1.203 The assessment of mental and behavioural disorders must be undertaken in accordance with the psychiatric impairment rating scale (PIRS) as set out in these Guidelines. Chapter 14 of the AMA4 Guides (pages 291–302) is to be used for background or reference only.

1.204 The PIRS draws heavily on Chapter 14 of the AMA4 Guides.

1.205 The AMA4 Guides provide a framework to determine whether a motor accident has caused psychiatric impairment. They bridge the gap between impairment and disability by focusing on four areas or aspects of functioning:

1.205.1 activities of daily living (ADL). Three aspects of ADL are used in the PIRS system

1.205.2 social functioning

1.205.3 concentration, persistence and pace

1.205.4 adaptation.

1.206 These areas are described in detail on pages 294–295 of the AMA4 Guides.

1.207 Activities of daily living include self-care, personal hygiene, communication, ambulation, travel and social and recreational activities.

1.208 Social functioning refers to the capacity to get along with others and communicate effectively.

1.209 Concentration, persistence and pace is defined as the ability to sustain focused attention, for long enough to permit the timely completion of tasks commonly found in work settings.

1.210 Adaptation (also called deterioration or de-compensation in work or work‑like settings) refers to the repeated failure to adapt to stressful circumstances.

1.211 Impairment is divided into five classes ranging from no impairment to extreme impairment.

1.212 Mental and behavioural disorders resulting from an organic brain injury are most suitably assessed as an organic problem under clause 1.156 to 1.176 in these Guidelines.

Assessment of mental and behavioural disorders

1.213 The impairment must be attributable to a psychiatric diagnosis recognised by the current edition of the Diagnostic & Statistical Manual of Mental Disorders(DSM) or the current edition of the International Statistical Classification of Diseases & Related Health Problems (ICD). The impairment evaluation report must specify the diagnostic criteria on which the diagnosis is based.

1.214 Impairment due to physical injury is assessed using different criteria outlined in other parts of these Guidelines.

1.215 The PIRS must not to be used to measure impairment due to somatoform disorders or pain.

1.216 Where cognitive deficits are suspected, the medical assessor must carefully consider the history of the injury, medical treatment and progress through rehabilitation. The medical assessor will also take into account the results of CT and MRI scans, electroencephalograms (EEGs) and psychometric tests.

1.217 The scale must be used by a properly trained medical assessor. The psychiatrist’s clinical judgement is the most important tool in the application of the scale. The impairment rating must be consistent with a recognised psychiatric diagnosis, and based on the psychiatrist’s clinical experience.

1.218 In order to measure impairment caused by a specific event, the medical assessor must, in the case of an injured person with a pre-existing psychiatric diagnosis or diagnosable condition, estimate the overall pre-existing impairment using precisely the method set out in this part of the Guidelines, and subtract this value from the current impairment rating.

The psychiatric impairment rating scale

1.219 Behavioural consequences of psychiatric disorders are assessed on six areas of function, each of which evaluates an area of functional impairment:

1.219.1 self-care and personal hygiene (Table 11)

1.219.2 social and recreational activities (Table 12)

1.219.3 travel (Table 13)

1.219.4 social functioning (relationships) (Table 14)

1.219.5 concentration, persistence and pace (Table 15)

1.219.6 adaptation (Table 16).

1.220 Impairment in each area of function is rated using class descriptors. Classes range from 1 to 5 according to severity. The standard form (Figure 2) must be used when scoring the PIRS. The classes in each area of function are described through the use of common examples. These are intended to be illustrative rather than literal criteria. The medical assessor should obtain a history of the injured person’s pre-accident lifestyle, activities and habits, and then assess the extent to which these have changed as a result of the psychiatric injury. The medical assessor should take into account variations in lifestyle due to age, gender, cultural, economic, educational and other factors.

1.221 Where adaptation cannot be assessed by reference to work or a work-like setting, consideration must be given to the injured person’s usual pre-injury roles and functions such as caring for others, housekeeping, managing personal/family finances, voluntary work, education/study or the discharge of other obligations and responsibilities.

Adjustment for the effects of treatment

1.222 An adjustment for the effects of prescribed treatment may be made by the medical assessor if all of the following requirements are met:

1.222.1 there is research evidence demonstrating that the treatment prescribed is effective for the injured person’s diagnosed psychiatric condition

1.222.2 the medical assessor is satisfied that the treatment has been appropriate, for example, medication has been taken in the appropriate dose and duration

1.222.3 there is clear clinical evidence that the treatment has been effective, that is, the injured person’s symptoms have improved and/or functioning has improved, and

1.222.4 it is the clinical judgement of the medical assessor that ceasing treatment will result in a deterioration of symptoms and/or a worsening in function.

1.223 The medical assessor may increase the percentage of WPI by:

1.223.1 0% WPI (no or negligible treatment effect)

1.223.2 1% WPI (a mild treatment effect)

1223.3 2% WPI (a moderate treatment effect), or

1.223.4 3% WPI (a full remission).

1.224 This clause does not apply to the use of analgesics, anti-inflammatory or antidepressant drugs for analgesia or pain management.

Calculation of psychiatric impairment

1.225 Rating psychiatric impairment using the PIRS is a three-step procedure:

1.225.1 Determine the median class score

1.225.2 Calculate the aggregate score

1.225.3 Convert the median class and aggregate score to % WPI.

1.226 Determining the median class score: Each area of function described in the PIRS is given an impairment rating ranging from class 1 to class 5. The six class scores are arranged in ascending order using the standard form (Figure 2). The median class is then calculated by averaging the two middle scores. For example:

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. 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 to nor interchangeable with impairment in other areas, the median seems the fairest way to translate different impairments onto a linear scale.

1.227 Calculation of the aggregate score: The aggregate score is used to determine an exact percentage of impairment within a particular class range. The six class scores are added to give the aggregate score.

1.228 Converting the median class and aggregate score: The median class and aggregate score are converted to a percentage impairment score using Table 17 ‘Conversion table’.

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Conversion table – Explanatory notes

1. Distribution of aggregate scores:

• The lowest aggregate score that can be produced is 1 + 1 + 1 + 1 + 1 + 1 = 6.
• The highest score that can be produced is 5 + 5 + 5 + 5 + 5 + 5 = 30.
• Table 17 therefore has aggregate scores ranging from 6 to 30.
• Each median class score has a range of possible aggregate scores and hence a range of possible impairment scores (for example, class 3 = 11% – 30% WPI).
• Table 17 distributes the impairment percentages across the possible range of aggregate scores.

2. Same aggregate score in different classes:

• Table 17 shows that the same aggregate score leads to different impairment percentages for different median classes. For example, an aggregate score of 18 is equivalent to an impairment rating of:
  • 10% in class 2
  • 22% in class 3, and
  • 34% in class 4
• This is because the injured person whose impairment is in median class 2 is likely to have a lower score across most areas of function. The injured person may be significantly impaired in one aspect of their life, such as travel, yet have low impairment in social function, self-care or concentration. In contrast, someone whose impairment reaches median class 4 will experience significant impairment across most aspects of their life.

Examples

Example A

Example B

Example C

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Other body systems

Respiratory system

1.229 The system of respiratory impairment classification is based on a combination of forced vital capacity (FVC), forced expiratory volume (FEV1) and diffusing capacity of carbon monoxide (DCO) or measurement of exercise capacity (VO2 max). Chapter 5 (pages 153–167, AMA4 Guides) should be infrequently used in assessing impairment following a motor accident. Healed sternal and rib fractures do not result in any assessable impairment unless they result in a permanent impairment of respiratory function.

1.230 Table 8 (page 162, AMA4 Guides) provides the classification of respiratory impairment. A footnote to the table reinforces that conditions other than respiratory disease may reduce maximum exercise capacity and medical assessors must carefully interpret the clinical presentation of the injured person.

1.231 The medical assessor must provide a specific percentage impairment for permanent impairment due to respiratory conditions. Table 8 (page 162, AMA4 Guides) must be used to classify the injured person’s impairment. Classes 2, 3 and 4 define a range of WPI percentages. The medical assessor must provide a specific percentage impairment within the range for the class that best describes the clinical status of the injured person. Class 2
(10-25% WPI) will need careful consideration.

1.232 Use of Tables 2 to 7 (pages 156–161, AMA4 Guides) may give rise to an inaccurate interpretation of lung function and impairment due to age or race. Where appropriate Tables 2 to 7 should be replaced with relevant guidelines from a substantial body of peer-reviewed research literature, which must be referenced.

Cardiovascular system

Introduction and assessment of the cardiovascular system

1.233 Chapter 6 (pages 169–199, AMA4 Guides) provides a clear explanation of the methods required for the assessment of the cardiovascular system.

1.234 The results from all relevant diagnostic tests must be taken into account by the medical assessor, including:

1.234.1 ECG (including an exercise ECG)

1.234.2 standard and trans-oesophageal echocardiogram

1.234.3 exercise thallium scan, exercise echo scan

1.234.4 coronary angiograms

1.234.5 operative notes for coronary artery bypass grafts, coronary angioplasty or other surgery

1.234.6 Holter monitoring results

1.234.7 electrodiagnostic studies

1.234.8 serum urea/electrolytes and urinalysis (particularly if hypertensive).

1.235 Diagnostic tests should not be ordered by the medical assessor for the purpose of rating impairment. This is in keeping with the approach taken elsewhere in Part 6 of the Guidelines.

1.236 Functional classification of cardiovascular system impairments: Table 2 (page 171, AMA4 Guides) should be used as an option if the medical assessor is not sure into which category the injured person should be placed based on specific pathology (refer to Tables 4–12, pages 172–195, AMA4 Guides). Table 2 can be used as a referee or umpire if there is doubt about the level of impairment that is obtained using the other recommended tables in this section.

1.237 Hypertensive cardiovascular disease (Section 6.4, pages 185–188, AMA4 Guides): This type of cardiovascular disease (Table 9, page 187, AMA4 Guides) requires medical documentation of the hypertension. If the injured person’s illness is controlled with medication, then they might not be assessable under this table. The medical assessor should refer to clauses 1.25–1.29 of these Guidelines.

1.238 Vascular diseases affecting the extremities (pages 196–198, AMA4 Guides): Impairments due to upper or lower extremity peripheral vascular disease resulting from vascular trauma must be assessed using the ‘Musculoskeletal’ Chapter of the AMA4 Guides. Tables 13 and 14 (pages 197–198, AMA4 Guides) must not be used.

1..239 Impairment scores from Table 17 ‘Impairment of the upper extremity due to peripheral vascular disease’ (page 57, AMA4 Guides) and Table 69 ‘Impairment of the lower extremity due to peripheral vascular disease’ (page 89, AMA4 Guides) must be converted to WPI.

Haematopoietic system

Introduction and assessment of the haematopoietic system

1.240 Chapter 7 (pages 201–207, AMA4 Guides) will be infrequently used in the motor accident context. The methods of impairment assessment suggested in this Part of the Motor Accident Guidelines should be used.

1.241 Splenectomy is covered in this chapter (page 205, AMA4 Guides). An injured person with post-traumatic splenectomy must be assessed as having 3% WPI.

Visual system

Introduction and assessment of the visual system

1.242 The visual system must be assessed by an ophthalmologist. Chapter 8 of the AMA4 Guides (pages 210–222) must be used.

1.243 Impairment of vision should be measured with the injured person wearing their corrective spectacles or contact lenses, if it was normal for the injured person to wear them before the motor accident, or if the need for such spectacles has become necessary due to normal physiological changes to the refractive error either in distance or near vision. If as a result of the injury, the injured person has been prescribed corrective spectacles and/or contact lenses for the first time, or different spectacles and/or contact lenses than those prescribed pre-injury, the difference should be accounted for in the assessment of permanent impairment.

Digestive system

Introduction and assessment of the digestive system

1.244 Assessments must be performed using the methods outlined in Chapter 10 (pages 235–248, AMA4 Guides).

1.245 Tables 2 to 7 in Chapter 10 (pages 239–247, AMA4 Guides) give details of the components to be assessed. Examples are given that assist by describing illustrative cases. Note that splenectomy is discussed in the ‘Haematopoietic system’ Chapter.

1.246 In Table 2, ‘Classes of impairment of the upper digestive tract’ (page 239, AMA4 Guides), the reference to Loss of weight below desirable weight does not exceed 10% in class 2 must be replaced with Loss of weight below desirable weight (if any) does not exceed 10%.

1.247 Upper digestive tract disease caused by the commencement and ongoing use of anti-inflammatory medications must be assessed as 0-2% WPI class 1 impairment according to Table 2 (page 239, AMA4 Guides). Upper digestive tract disease caused by the use of anti-inflammatory medications resulting in severe and specific signs or symptoms must be assessed as a class 2 impairment according to Table 2 (page 239, AMA4 Guides).

1.248 Colonic and/or rectal disease caused by the use of opiate medication must be assessed as 0–2% WPI class 1 impairment according to Table 2 (page 239, AMA4 Guides). Assessment of constipation alone results in 0% WPI.

1.249 Table 7 (page 247, AMA4 Guides): In classes 1 and 2 the first criterion must be present, together with the second or third criterion. In class 3, all three criteria must be present.

Urinary and reproductive systems

Introduction and assessment of the urinary and reproductive systems

1.250 Chapter 11 (pages 249–262, AMA4 Guides) is used for the assessment of urinary and reproductive systems and provides clear methods for assessing impairment in these systems.

1.251 For male and female sexual dysfunction, objective pathology should be present for an impairment percentage to be given.

1.252 Objective evidence of neurological impairment is necessary to assess incontinence related to spinal injury (AMA4 Guides, Chapter 4, 4.3d). Objective evidence of injury to the bladder and urethra associated with urinary incontinence is necessary to assess urinary incontinence due to trauma (AMA4 Guides, Chapter 11, 11.3 and 11.4)

Endocrine system

Introduction and assessment of the endocrine system

1.253 Chapter 12 (pages 263–275, AMA4 Guides) is used to assess the endocrine system. Each endocrine organ or system is listed separately.

1.254 Where an impairment class defines a range of WPI percentages the medical assessor must define a specific percentage impairment within the range described by the class that best describes the clinical status of the injured person and provide reasons.

1.255 Where injury has resulted in fat necrosis in the mammary glands this must be assessed using Chapter 13 ‘The skin’ (pages 278–289, AMA4 Guides).

1.256 Section 12.8 ‘Mammary glands’ (page 275, AMA4 Guides) is replaced by these Guidelines. Total loss of one or both mammary glands is deemed to be an impairment of greater than 10% WPI.

1.257 Injury to the breast(s) caused by damage to a breast implant(s) must be assessed as class 1, Table 2 (page 280, AMA4 Guides).

Skin

Introduction and assessment of the skin

1.258 Chapter 13 (pages 277–289, AMA4 Guides) refers to skin diseases generally. In the context of injury, Sections 13.4 ‘Disfigurement’ (page 279, AMA4 Guides) and 13.5 ‘Scars and skin grafts’ are particularly relevant.

1.259 The assessment of permanent impairment involving scarring of the face may be undertaken using Chapter 13 ‘The skin’ (pages 279–280, AMA4 Guides) and/or Section 9.2 ‘The face’ (pages 229–230, AMA4 Guides). Criteria for facial impairment are listed on page 229 of the AMA4 Guides. Specific facial disfigurements may also be assessed by reference to Table 4 (page 230, AMA4 Guides).

1.260 Disfigurement, scars and skin grafts may be assessed as causing significant permanent impairment when the skin condition causes limitation in performance of activities of daily living. Assessment should include a history that sets out any alterations in activities of daily living. The AMA4 Guides (page 317) contain a table of activities of daily living. Any impairment secondary to severe scarring, such as contracture or nerve damage, is assessed using other chapters and combined with the assessment for scarring.

1.261 A scar may be present and rated 0% WPI.

1.262 Table 2 (page 280, AMA4 Guides) provides the method of classifying impairment due to skin disorders. Three components – namely signs and symptoms of skin disorder, limitation of activities of daily living and requirements for treatment – define five classes of impairment. Determining which class is applicable is primarily dependent on the impact of the skin disorder on daily activities. The medical assessor must derive a specific percentage impairment within the range described by the class that best describes the clinical status of the injured people. All three criteria must be present. Impairment values are WPI.

1.263 When using Table 2 (page 280, AMA4 Guides), the medical assessor is reminded to consider the skin as an organ. The effect of scarring (whether single or multiple) is to be considered as the total effect of the scar on the organ system as it relates to the criteria in Table 2 ‘Table for the evaluation of minor skin impairment’ (TEMSKI). Multiple scars must not be assessed individually. The medical assessor must not add or combine the assessment of individual scars, but assess the total effect of the scarring on the entire organ system.

1.264 The TEMSKI (Table 18) is an extension of Table 2 (page 280, AMA4 Guides). The TEMSKI divides class 1 into five categories of impairment. When a medical assessor determines that a skin disorder falls into class 1, they must assess the skin disorder in accordance with the TEMSKI criteria. The medical assessor must evaluate all scars either individually or collectively with reference to the five criteria and 10 descriptors of the TEMSKI. The medical assessor should address all descriptors.

1.265 The TEMSKI is to be used in accordance with the principle of best fit. The medical assessor must be satisfied that the criteria within the chosen category of impairment best reflect the skin disorder being assessed. The skin disorder should meet most, but does not need to meet all, of the criteria within the impairment category in order to satisfy the principle of best fit. The medical assessor must provide reasons as to why this category has been selected.

1.266 Where there is a range of values in the TEMSKI categories, the medical assessor should use clinical judgement to determine the exact impairment value and provide reasons that clearly link their clinical judgement to the impairment value selected.

1.267 For the purpose of assessing fat necrosis, Chapter 13 ‘The skin’ (pages 277‑289, AMA4 Guides) may be used by analogy where appropriate.

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Acknowledgements

The first version of these Guidelines was developed for the then NSW Motor Accidents Authority by a consortium comprising Dr Jim Stewart, Associate Professor Ian Cameron, Associate Professor Malcolm Sim and Professor Peter Disler. The bulk of the task was undertaken by seven clinical reference groups, whose members are listed below. Particular mention should be made of the extensive contributions of Dr Dwight Dowda, Professor Sydney Nade and Dr Julian Parmegiani.

A number of Victorian clinicians with experience in the use of the AMA Guides (second and fourth editions) have provided valuable assistance. They are Dr Neil Cullen, Dr Michael Epstein, Dr Peter Lothian, Dr Gary Speck, Dr Richard Stark and Dr Nigel Strauss. Dr Alan Rosen provided valuable comment on the PIRS.