Catastrophic Impairment:

Transcription

1 Catastrophic Impairment: The New Definitions (Mental and Behavioural Impairment) The AB Justice League Agenda November 17, 2017 William H. Gnam, PhD, MD, FRCPC Psychiatrist

2 Outline New Method: assigning mental whole person impairment using the AMA Guides, 6 th edition New Threshold: implications of raising the threshold to three Marked (Class 4) ratings Predictions and Foreseeable Challenges

3 Combining Physical and Mental Impairments in the Revised SABS: New Method

4 The Previous SABS Definition (2) For the purposes of this Regulation, a catastrophic impairment caused by an accident is,.. (e) subject to subsections (4), (5) and (6), an impairment or combination of impairments that, in accordance with the American Medical Association's Guides to the Evaluation of Permanent Impairment, 4th edition, , results in 55 per cent or more impairment of the whole person;

5 The Previous SAB Definition This definition had become interpreted to indicate that the combination of whole person impairment can include mental whole person impairment (combined with physical WPI). However, the AMA Guides, 4 th edition does not provide a method to rate mental WPI

6 The Previous SABS WPI RATING METHOD In Ontario, two methods were adopted to assign mental WPI: Rating by Analogy with Tables 2 or 3 of Chapter 4 (AMA Guides, 4 th edition) The California Method Both were methods were to be used with clinical data following a comprehensive Psychiatric/Psychological Examination The two methods yield very similar WPI scores No 4 th edition Guidance on choosing a particular WPI score, but there is extensive general guidance on impairment assessment principles

7 The California Method First obtain an overall impairment rating (between 0 and 100) using the Global Assessment of Functioning Scale, a well-known disability rating scale in Psychiatry Then, using a conversion table published by the Worker s Compensation Board of the State of California, convert the GAF score to a Whole Person Impairment Score

8 Rating by Analogy: AMA Guides, 4 th ed., Chapter 4 Table 3

9 Table3 Chap4 vs. California WHOLE PERSON IMPAIRMENT (%) Tab 3 Ch4 California 0 0 MENTAL IMPAIRMENT (Mild, Moderate, Marked, Severe)

10 The Revised (Current) SABS Definition (7) Subject to subsections (2) and (5) a mental or behavioural impairment, excluding traumatic brain injury, determined in accordance with the rating methodology in Chapter 14, Section 14.6 of the American Medical Association s Guides to the Evaluation of Permanent Impairment, 6th edition, 2008, that, when the impairment score is combined with a physical impairment described in paragraph 6 in accordance with the combining requirements set out in the Combined Values Table of the American Medical Association s Guides to the Evaluation of Permanent Impairment, 4th edition, 1993, results in 55 percent or more impairment of the whole person.

11 The Revised Definition: Rating Mental WPI If the New Definition applies only to Section 14.6 of the 6 th edition, the general principles for conducting assessments and rating mental impairment from the 4 th edition will still apply The rating procedure of the AMA Guides, 6 th edition and the previous procedure (based on 4 th edition) differ substantially by: Rating Method Calibration (Discounting)

12 AMA Guides, 6 th edition rating method 1. Complete a comprehensive clinical examination 2. Derive three scores by evaluating patients using three different scales: a) Brief Psychiatric Rating Scale (BPRS) b) The Global Assessment of Functioning Scale (GAF) c) The Psychiatric Impairment Rating Scale (PIRS) 3. Weight each of the scores to obtain three mental whole person impairment scores 4. Choose the Median (middle) Value of the three

13 AMA Guides, 6 th edition method Brief Psychiatric Rating Scale (Extended): Measures the major symptoms of mental disorders, not functional impairments The BPRS Score is the sum of 24 item scores 24 Items: scored from 1 (Not Present) to 7 (Extremely Severe) Items are based on combination of patient s self-report and observed behaviour and speech Semi-structured format

14 The BPRS

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16 Pros and Cons of the BPRS Well established and good reliability, validity Semi-structured format promotes greater clinical diligence, enhances reliability Emphasis on Psychotic and other symptoms not generally applicable to MVA injury populations Time-consuming!!!! Symptom severity is an imprecise proxy for mental impairments

17 The Psychiatric Impairment Rating Scale (PIRS) Rate (scale of 1 to 5) functional impairment on 6 scales: Self-care and personal hygiene Social and recreational activities Travel Interpersonal relationships Concentration, Persistence and Pace Employability and Resilience Arrange the 6 scores from highest to lowest Take the middle two scores by rank and add

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19 PIRS: Pros and Cons Compared to 4 th edition, more direction on how to choose a score However, examples (text anchors) could be restrictive if interpreted very strictly. The scoring of some of the 6 scales features large increments in impairment for a one-point increase on the scale

20 The GAF Impairment scale 5-point jumps in mental WPI for every 10 point decrease in the GAF Text anchors for every 10 points on GAF For the vast majority of persons in motor vehicle accidents, the maximum WPI score will be 20%

21 The GAF: Pros and Cons Reliability was acceptable for research studies with rater training, but is likely mediocre or even unacceptable in routine clinical use Major limitation is the conflation of symptom severity with functional impairment The conflation results in problematic rating scenarios

22 The Major Implication of the New Definition: Discounting The AMA Guides 6 th Tables that translate (calibrate) the scores from the 3 rating scales to mental WPI will result is a significant discounting of mental WPI compared to the current SABS The magnitude of the discount is complicated to calculate due to the fact that only the Median (middle) score of the three scales is chosen

23 Discounting: the Bottom Line If the maximum feasible WPI scores for the MVA population with the 3 scales are: GAF: 20% WPI PIRS: 30% WPI BPRS: 50% WPI Then the median score of 30% WPI will be maximum. More realistically, Mild mental impairments will be 5% WPI, Moderate 10-15%, and Marked 20%.

24 Implications and Predictions Adding the 6 th edition rating methods to Psychiatric/Psychological CAT Examinations will require significant additional clinician examination time. (A separate examination.) The clinical rationale and details of the 6 th edition ratings will not be transparent to readers without disclosure in reports of details of the 3 scales completion

25 Implications and Predictions The 6 th Edition method follows good measurement theory practice by measuring an abstract concept ( mental impairment ) in different manners, and taking the median value The difficulties ahead will predominantly be related to practical interpretation of the direction provided by the scales There will be other implications for discounting of mental WPI vs. the previous SABS rating system

26 Implications and Predictions There has never been a conceptual, moral or clinical rationale (from the Expert Panel, or others) for the discounting that will occur Equity issues arise directly because the same functional impairments will be assigned a higher rating if caused by traumatic brain injury than if caused by other mental disorders Accordingly, there will be a new incentive to argue that mental impairments are directly attributable to the effects of brain injury, in cases with a history of mild traumatic brain injury

27 THE REVISED SABS DEFINTIONS: A New Threshold

28 The previous SABS MB CAT Definition (2) For the purposes of this Regulation, a catastrophic impairment caused by an accident is, (f) subject to subsections (4), (5) and (6), an impairment that, in accordance with the American Medical Association's Guides to the Evaluation of Permanent Impairment, 4th edition, 1993, results in a class 4 impairment (marked impairment) or class 5 impairment (extreme impairment) due to mental or behavioural disorder. 5 O. Reg. 34/10, s. 3 (2).

29 The Chapter 14 (4 th ed.) Rating Table Reference

30 The Revised SABS Definition Section 3.1(1): 8. Subject to subsections (3) and (5), an impairment that, in accordance with the American Medical Association s Guides to the Evaluation of Permanent Impairment, 4th edition, 1993 results in a class 4 impairment (marked impairment) in three or more areas of function that precludes useful functioning or a class 5 impairment (extreme impairment) in one or more areas of function that precludes useful functioning, due to mental or behavioural disorder.

31 Raising the Threshold The previous SABS Definition was interpreted to set the CAT threshold at a single Marked (Class 4) rating in one of the four domains Roughly, a single Marked (Class 4) impairment rating corresponds to a GAF of approximately 48 50: any serious impairment in social occupational, or school functioning (e.g., has no friends, is unable to keep a job)

32 Raising the Threshold: implications Under the revised SABS, three Marked impairment ratings would reduce the corresponding GAF score to 40 or lower ( major impairment in several areas, such as work or school, family relations, judgment, thinking or mood (eg, depressed adult avoids friends, neglects family, and is unable to work;)

33 Raising the Threshold: implications Although the change in GAF score may appear minor (only 10 points), the clinical differences are very significant, as the proportion of patients meeting the lower GAF threshold falls precipitously. It is difficult to predict quantitatively the reduction in cases of mental and behavioural impairment reaching the catastrophic threshold, but all indicator imply severe reductions

34 Raising the Threshold: implications For example, from my own practice (of >1000 catastrophic impairment examinations), the proportion of persons meeting the current CAT threshold that have three Class 4 impairment ratings is 15 20%, implying at least a five-fold reduction. If precludes useful functioning is interpreted as precluding effective functioning, the new CAT threshold might only be satisfied by institutionalized patients.

35 Raising the Threshold: implications There may be partially countervailing factors that diminish the restrictiveness of the new definition: Alternate interpretations of useful functioning that are less restrictive Clarifications of the Marked (Class 4) threshold, especially in Concentration and Pace, which have the effect of lowering the threshold Raising the threshold may not substantially reduce the rate of completion of OCF-19s by certain examiners

36 Predicting the Impact of the New Definitions The actual effects of raising the threshold to three Marked impairment ratings are difficult to predict The new mental WPI ratings will require additional training and assessment procedures, especially to complete the BPRS and PIRS supported by evidence (a separate examination?!) In order for the rating process to be transparent, greater documentation of actual scale values (and justification) will be required.

37 Predictions In cases of mild traumatic brain injury and co-occurring mental disorders, be prepared for arguments that all mental impairments are caused by TBI (and therefore merit a higher WPI rating) Due to the multiple scale method of mental WPI Definition, there likely will be greater convergence in ratings from different examiners, as minor variations in expert ratings do not necessarily translate into a different final mental WPI score Because the rating system of Chapter 14.6 is more determinate and concrete (when compared to 4 th edition methods), apportionment may be more feasible for cases with pre-existing mental impairments documented in pre-mva psychological or psychiatric reports.