Partner, Rucka, O'Boyle, Lombardo & McKenna

The use of impairment and the eclipse of disability is a dangerous trend for injured workers.

The current trend in the large majority of workers’ compensation jurisdictions in the United States is towards adopting The AMA Guides for the Evaluation of Permanent Impairment as the gatekeeper to receipt of permanent disability benefits.  California is the latest jurisdiction to adopt the mandatory use of the Guides as of January 2005.

By using impairment ratings from the Guides, essentially as a proxy for disability, permanent disability benefits are being slashed.  The use of impairment and the eclipse of disability as the relevant permanent consequence of an injury in workers’ compensation is a dangerous trend for injured workers. The latest [6th] edition of the Guides accelerates this decline.

The American Medical Association’s Guide to the Evaluation of Permanent Impairment, The Sixth Edition, was published in late December 2007.  Fifteen states, some Canadian provinces, six nations, several Federal systems, and some States’ no-fault personal injury schemes require the use of the “most recent Edition” of the Guides pursuant to statute, code, or regulation.  Alaska, Hawaii, Kentucky, Louisiana, Mississippi, Montana, New Hampshire, New Mexico, Ohio, Oklahoma, Pennsylvania, Rhode Island, Tennessee, Vermont, and Wyoming are employing the Sixth Edition, although there are or will be disputes in several of these jurisdictions over the introduction of the Sixth Edition.¹

In Ohio, the Guides are not statutorily required but administrative agencies use the Guides as a matter of informal policy.  Phil Fulton, Ohio Bureau of Workers’ Compensation Board of Directors (and a WILG Director) is calling for blocking the use of the Sixth Edition.  In Kentucky, Ched Jennings, WILG Treasurer, reports HB 498 passed by a vote of 67-26 in the House to keep the Fifth Edition of the Guides instead of “the latest edition.”  Members of Kentucky-WILG, the Kentucky Justice Association, and the State AFL-CIO have worked diligently on this measure.  The bill now goes to the Kentucky Senate. Passage is expected but by a closer vote. Colorado, which uses the Third Edition, Revised and New York are currently in the crosshairs for crossover studies and possible adoption of the Sixth Edition. 

The Sixth Edition will be utilized in Federal workers' compensation systems, which cover all federal employees,² Federal Employer's Liability Act (FELA), and citizens of Washington, D.C.

Other Federal systems using the Sixth Edition include the Energy Employees Occupational Illness Compensation Program Act (EEOICPA) and Longshore and Harbor Workers’ compensation Act (LHWCA).  Under FECA, benefits are provided for permanent impairment to specific body parts including extremities, hearing, vision, and loss of specific organs.  The Longshore and Harbor Workers’ Compensation Act calls for use of the Guides for hearing loss and occupational diseases in retiree claims.³

The most recent edition serves as a criterion for automobile personal injury cases in some jurisdictions.  Suits under no-fault automobile insurance may use impairment thresholds defined by the Guides.  In Florida, where personal injury protection coverage exists, an insured’s claim for pain and suffering is often subject to limits that use the Guides to define  “significant and permanent loss of an important bodily function”.⁴

The province of Ontario uses the Sixth Edition to adjudicate motor vehicle accidents.  Abroad, Australia, Canada, Hong Kong, Korea, New Zealand, and South Africa utilize the Guides most recent edition in some form. New Zealand uses the Guides for all personal injury cases.⁵

In the workers’ compensation arena, the use of the AMA Guides may be mandatory or recommended.  Some jurisdictions use impairment as a proxy for disability.  Some take impairment ratings and plug them into a formula that purports to produce a disability rating.  In California, for example, the courts are struggling with how to modify an impairment standard to produce a “diminished future earnings capacity” rating. Since there appears to be no meaningful empirical correlation between impairment and loss of earning capacity, the search for an appropriate modifier is elusive.  Other jurisdictions use the impairment rating as a threshold for defining a serious injury or illness.  Some jurisdictions use the Guides for nonscheduled injuries only, while others use it for all injuries.

The process for developing the Sixth Edition was driven by an Editorial Panel and an Advisory Committee. The Editorial Panel included: a Medical Editor, Robert Rondinelli, MD; five Section Editors including Elizabeth Genovese, MD, Richard Katz, MD, Kathryn Mueller, MD, Mohammed Ranavaya, MD, and Tom Mayer, MD; and, a Senior Contributing Editor, Christopher R. Brigham, MD.

Diagnostic categories were chosen and a modified Delphi panel approach (“expert opinion”) was used to build consensus.  The Editors assert that where there was no compelling reason to change impairment ratings from previous editions, consistency with earlier editions prevailed.⁶   This statement seems at odds with the many unexplained changes, mostly lowering values, in the latest edition. At any rate, when the Guides speak of “consensus based ratings”, for all practical purposes this refers to the above group.  There is, by all accounts, a paucity of actual evidence-based ratings.  The Advisory Committee also appears to have on ongoing role in the development of future editions. ⁷

The New Paradigm

The Sixth Edition consists of 17 chapters and 634 pages compared to the Fifth Edition’s 18 chapters and 613 pages.  There are 223 tables and 68 figures.  The cardiovascular system now comprises only one chapter instead of the two in previous editions.

Most importantly, the Sixth Edition touts a new approach to rating impairment.  Its hybrid methodology makes claim to increased internal consistency, standardization, ease of application, and a simplified rating process.  But insofar as this may be true, it is at the expense of validity, and the process has resulted in the same old fiat ratings, only at lower values.

The new model attempts to graft the conceptual framework of the International Classification of Functioning, Disability, and Health (ICF) model of disablement developed by the World Health Organization, on to a diagnostic-based grid template. The ICF is a classification of health and health related domains that describe body functions and structures, activities, and participation.  Following the ICF terminology, “disability” is redefined in the Sixth Edition as “activity limitations and/or participation restrictions in an individual with a health condition disorder or disease.” ⁸

This is a significant retrenchment from Fifth Edition’s definition of disability as “alteration of an individual’s capacity to meet personal, social or occupational demands or statutory or regulatory requirements because of an impairment.” ⁹

The ICF’s taxonomy is etiologically neutral and links health conditions to an ordinal level of clinical severity, as indicated in Table 1-3.  Most relevant to impairment ratings, the ICF classification uses five impairment classes, from one having “no problem” to one having a “complete problem” (total), within the domains of mobility and self-care.

The anatomical approach for musculoskeletal assessments used in prior editions is replaced by a uniform diagnosis-based approach.  The Sixth Edition developed diagnosis-based grids for each organ system.  Consensus-based criteria classify diagnoses for a particular organ or body part.  The five classes of impairment, or some subgroup of these, are used within each diagnosis.

Impairment class assignment is based on “key factors” which are comprised, generally, of a history of clinical presentation, physical findings, or clinical studies.  However, for the spine and extremities, diagnosis alone determines class placement in the grid. Spine and extremities injuries constitute the majority of industrial claims. For the most part, each class is divided into five grades.  The medium grade is considered the default rating. 

The impairment rating is calculated by adjusting the initial impairment rating by modifiers (“non-key factors”), which may include physical findings, clinical tests results, and self-reports on ADL scales.  However, the non-key factors cannot move the rating into another class.¹⁰  The Sixth Edition differentiates between the relative contributions of history of clinical presentation, physical findings, and objective test results; this varies by chapter.  Choice of diagnosis and choice of impairment class are the two most important elements in determining the final impairment rating.

Although the basic template of the diagnosis-based grid is common to each organ system and chapter, there is some variation in the factors used to develop the impairment rating, depending on the body part.  Some organ systems do not use all these factors.  For example, the endocrine chapter uses burden of treatment compliance (BOTC) as a key factor.  In the musculoskeletal chapters, BOTC is said to be considered already as part of the “History of Clinical Presentation” component.¹¹

The regional versus whole person hierarchy and the combined values chart remain unchanged from earlier editions.  The rules of application regarding rating only at maximum medical improvement and the role of examiners are similar to prior editions.  However, Table 2-1, “Fundamental Principles of the Guides”, item 6, states “Chiropractic doctors, if authorized by the appropriate jurisdictional authority to perform ratings under the Guides, should restrict ratings to the spine.” ¹²

The American Chiropractic Association has filed a letter with the American Medical Association demanding revision of Table 2-1.  The letter alleges restraint on competition by preclusion from performing impairment ratings involving musculoskeletal conditions.¹³

According to the Editors, the use of a generic template will promote greater internal consistency between chapters than realized in early editions.¹⁴   The central premise of the Sixth Edition is that diagnosis is the essence of impairment rating.  Since physicians are good at the diagnostic exercise, ratings will be more consistent. Unfortunately, ratings will also be less valid.

There should be no mistake: use of the ICF model does not mean the Guides have been transformed into an instrument for rating disability.  The Sixth Edition, like its predecessors, makes no claim to evaluating anything other than impairment.

Incorporating certain aspects of the ICF model into the impairment rating process is certainly a step in the right direction.  Attempts to integrate impairment rating with the ICF constructs for activity limitations and limitations in participation is a positive paradigm shift.  Unfortunately, the effort is flawed by use of a taxonomy of tables and figures rather than actually measuring impairment.

The simple creation of a numerical series of tables and figures produces no common metric.  This is an act of enumeration, a mute ground upon which it is possible to juxtapose tables and figures. What field of identity sustains them?  Whole person impairment is measured by the impact on ADLs.¹⁵  Yet, ADL scales are relegated to non-key factors in the new paradigm.  Along with the elimination of pain add-ons, all this spells a further retreat from any valid paradigm for the science of impairment.

Impairment Values in the Sixth Edition

Some reviewers have predicted a 40% reduction in the value of impairment ratings from the Fifth Edition to the Sixth Edition of the Guides.  The impact of changes in ratings cannot be fully appreciated until more cases are rated and comparative studies issue, where cases are rated under both the Fifth and Sixth Editions. 

At any rate, all indications point to a substantial decrease in impairment values in the Sixth Edition.  First, impairment is redefined as “significant deviation, loss, or loss of use of any body structure or body function in an individual with a health condition, disorder or disease.”¹⁶  The Sixth Edition adds the word “significant” to the definition.

Dr. Brigham, the Senior Contributing Editor in the Sixth Edition and Guides Newsletter entrepreneur, performed comparative studies of ratings under the Third Edition, Revised, Fourth Edition, and Fifth Edition.  He concluded that the Fourth and Fifth Editions are more complex than the Third Edition, Revised, and in general, required more effort by rating physicians and result in lower ratings.¹⁷

In his article entitled “Misuse and Abuse, AMA Guides to the Evaluation of Permanent Impairment,” Dr. Brigham opines that the correct whole person impairment ratings should average six percent and that it is uncommon to see accurate ratings beyond 30 percent whole person…”.¹⁸

Most impairment ratings are “erroneously elevated,” according to this article.  In a national study of 2100 cases, 89% were “substantially higher than appropriate,” he claims.  Brigham concludes, “The AMA Guides to the Evaluation to Permanent Impairment, Fifth Edition are widely used and most of the ratings are erroneous and higher than appropriate.”¹⁹

Dr. Brigham will undoubtedly attempt to argue that the Sixth Edition is not “that much” lower than the Fifth Edition.  It’s just that so many of the ratings under the Fifth were “done incorrectly.” 

Dr. Brigham correctly observed that typically the ROM method rates higher than DRE method in the spine.²⁰  So it is no surprise that the ROM method for the spine is eliminated in the Sixth Edition.  The ROM method uses a functional as well as a diagnostic component to more accurately reflect an individual’s deviation from normal functioning. 

The elimination of the ROM method is a telling example of a “take-away” in the Sixth Edition. Consistency in this Edition is achieved by eliminating consideration of an individual’s ability to function.  Functional assessment in the Sixth Edition is brought in, if at all, only as a modifier of limited import to the final rating.

There are two systems for rating spinal impairment in the Fifth Edition: the diagnostic related estimate (DRE) and the range of motion model (ROM).  Challenges to the use of the ROM method have revolved around concerns about the relationships among mobility deficits, functional loss, and impairment as well as establishing normative data and accuracy of measurement techniques.  There are obvious problems intrinsic to human performances measurement.²¹  Nonetheless, loss of motion is observable and quantitatively measurable.  Functional factors like strength, endurance, and coordination are more individualized, and the ROM considers factors not accounted for by DRE.  It lacks reliability only insofar as it is prone to voluntary restriction by suboptimal effort. 

One of the fundamental principles of the Guides is that impairment evaluations should be grounded in functional loss.  Despite this time-honored precept, the Sixth Edition not only favors the DRE method for evaluating the spine, now named “diagnostic-based estimate,” but has eliminated the ROM method.

The DBE method for rating impairment is problematic on several levels.  A single diagnosis may be associated with wide variations of functional impairment.  DBE rates by indicators or abnormality in the structure of the spine and function of nerve roots.   DBE precludes from consideration developmental aspects, such as osteoarthritis or herniated discs without radiculopathy.  DBE categories are not defined by experimental procedures or measurements, and thus are devoid of empirical meaning.  DBE focuses on pathology, rather than functional loss.

The DRE method, used in prior editions, has been found unreliable as a matter of law in some jurisdictions because it rates by diagnosis, not by measuring impairment.  Several states prohibit the use of DRE method for rating spine impairments.  In West Virginia, the DRE method was found unreliable because it fails to consider either developmental findings or sequential injuries, and was designed for traumatic injuries.²²

Ratings for spinal fusions will receive lower ratings in the Sixth Edition as well.  There may be some ratings at the lower end that were previously unrated, such as non-specific spinal pain, now Class 1 in the Sixth Edition, or lateral epicondylitis. Causation analysis, however, is directed towards apportioning to risk factors like gender, age, and weight.

Perhaps the most egregious take-away in the Sixth Edition is the further deprecation of pain as a factor in impairment ratings. The pain add-ons in the Fifth Edition are no longer permitted in the Sixth Edition.  Pain-related impairment is allowed pursuant to Chapter 3 only if the patient presents with a painful condition and cannot be rated according to principles outlined in chapters 4 through 17.²³   The limit still is 3 percent.  The Pain Disability Questionnaire (PDQ) is the psychometric tool of choice for assessing pain.²⁴

The Sixth Edition essentially maintains that if there is an objective finding that supports a pain compliant, no pain add-on is permitted.  This is the old “its already in the conventional impairment rating” position.  A pain add-on, according to this perspective, is “double dipping.”

It is not clear how pain was factored into the development of the conventional impairment ratings. There is no hint as to what the process was, if any.  Most reasonable minds would admit the notion that the purported inclusion of pain in the conventional impairment rating is a fiction.

The demand that all impairment be verified by objective findings is at odds with a realistic understanding of how injury and disease disable people.  Apart from a few conditions–such as loss of limb, blindness or a coma–most injuries do not prevent people from working due to mechanical failure.  Rather, a worker is disabled by a variety of unbearable sensations attempting to work.  It is called the “5th vital sign,” or pain.

The scientific understanding of pain has increased geometrically in recent years, yet the Sixth Edition takes two steps backwards with respect to rating pain impairment. Some previous pain chapter contributors have distanced themselves from or have openly rejected the Sixth Edition’s treatment of pain impairment.

Examples of rating reductions in the Sixth Edition include the following:

• 15-9, region: elbow, class: 1, diagnosis: distal biceps tendon rupture, Sixth Edition impairment (WPI%): 4% Fifth Edition impairment (WPI%): 6%
• 15-12, region: Shoulder, class: 2, diagnosis:  total shoulder arthroplasty, Sixth Edition impairment (WPI%) 13% Fifth Edition impairment (WPI%): 14%
• 16-5, class: 3 diagnosis: ankle arthritis, Sixth Edition impairment (WPI%) 10% Fifth Edition impairment (WPI%) 12%
• 16-6, class: 5 diagnosis: s/p total ankle replacement with poor result, Sixth Edition impairment (WPI%)24% Fifth Edition impairment (WPI%) 30%
• 16-11,  class: 3 diagnosis: s/p Total knee replacement, Sixth Edition impairment (WPI%) 15% Fifth  Edition impairment (WPI%)  20%
• 16-15, class: 3, diagnosis: hip fracture, Sixth Edition impairment (WPI%) 12%, Fifth Edition impairment (WPI%) 25%
• 17-3, region: cervical, class: 1, diagnosis: Intervertebral disk herniation or AOMSI at a single level (status posted herniated nucleus pulposus and anterior cervical diskectomy and fusion at C5-6 with intermittent left arm pain, Sixth Edition impairment (WPI%): 7%, Fifth Edition impairment (WPI%):  25%
• 17-4, region: cervical intervertebral disk herniation  or AOMSI at a single level (cervical disk herniation with C8 radiculopathy), Sixth Edition impairment (WPI%): 12%, Fifth Edition impairment (WPI%): 18%
• 17-5, region: cervical, class: 3, diagnosis: intervertebral disk herniations and AOMSI at multiple levels (cervical disk herniations at 2 levels, with unresolved radiculopathy at single level), Sixth Edition impairment (WPI%): 15%, Fifth Edition impairment (WPI%): 20%

Challenging the AMA Guides

Constitutional challenges to the Guides have enjoyed no real success, thus far.  As long as a statute adopting the Guides does not blatantly misuse the Guides by making direct financial awards based solely on Guides’ percentages, it appears to be able to pass constitutional muster.

In Texas, it was argued that Guides’ impairment ratings are not designed to award disability benefits.  By the Guides’ own admission, impairment is not disability and the impairment values assigned in the Guides are not scientifically valid.

The Texas Supreme Court, applying the rational basis test, upheld use of the Guides since there were mediating factors, like age and occupation, between Guides’ impairment rating and payment of permanent disability benefits.  The Court implied that a strictly impairment for dollar scheme may not be upheld.²⁵

In Oklahoma, the Courts rejected the argument that adoption of the Guides is an unconstitutional delegation of power by the legislature by vesting authority in a purely privately-controlled organization whose decisions are nontransparent and without any restrictions or standard.²⁶

The Tennessee Supreme Court summed up best what appears to be the general jurisprudential view: that the Guides are imperfect but not unconstitutional.  Uniformity and predictability are reasonable and legitimate state interests.  The Guides purport to advance these interests and legislators believe it.  Therefore, use of the Guides passes the reduced scrutiny of the rational basis test.²⁷

There still may be some room for constitutional attacks on how the Guides are applied.  If an injured worker receives a zero under the conventional impairment rating and is unable to return to the normal and customary job because of work restrictions, then it is arguably unconstitutional to deny permanent disability benefits.  Where there is demonstrative permanent wage loss, a case can be made that it is unconstitutional to deny all permanent disability benefits.  No part of public policy is rationally served by denying equal permanent disability benefits to workers with permanent wage loss and zero conventional impairment ratings.

Although the incorporation of an existing standard is permissible, the adoption of a future standard would be an unconstitutional delegation of legislative power.  A statute that attempts to incorporate future changes of another statute, code, regulation, or guidelines is an unconstitutional delegation of legislative power.²⁸ 

The ever-increasing frequency of Editions and variability in rating values and methods is disruptive, unpredictable, and without any scientific foundation.  The burden should be shifted to the AMA to produce a valid paradigm before any jurisdiction adopts a new edition of the Guides.

Despite the paradigm shift in the Sixth Edition, the fundamental conceptual confusion at the heart of the Guides’ project remains.  Whole “Person Impairment” (WPI) is defined as percentages that estimate the impact of the impairment on an individual’s overall ability to perform ADLs, excluding work.²⁹ 

Nonetheless, functional limitations—as measured by ADL scales—are downgraded to a mere modifier status within an impairment class.  Some chapters include an assessment of the “Functional History,” but only as one of the non-key factors to adjust the final impairment rating within a class by using a self-report tool such as the PDQ, QuickDASH, Lower Limb Outcomes Questionnaire, or some alternative ADL scale.³⁰

The Sixth Edition advises physicians to include functional assessment as part of their regular impairment rating examination, and to observe the patient directly in performing  functional tasks in order to judge the accuracy of self-reports.³¹  The examining physician may score the self-report tool and adjust the impairment rating higher or lower than the default value.  The burden is on the rating physician to provide a rationale for deciding that functional test results are clinically consistent and credible.

Further restrictions on the proper use of ADL analysis include the direction that Functional History Grade Modifier should be applied only to the single, highest diagnosis-based Impairment.³²

The Sixth Edition is quite critical of previous editions of the Guides for lack of validity due, in part, to inadequate attention to functional assessment.   In prior Editions, the role of functional, as distinct from anatomic, loss in the impairment rating protocol has varied greatly by organ system and the availability of functional data.

The respiratory system in the Fifth Edition employs functionally-based classification of dyspnea in relation to ADL.  Impairment ratings have been developed based on results of pulmonary functional assessments as well.  The New York Heart Association issued a 4-class, functionally based scheme (NYHA classes I-IV) according to symptoms with activity and overall functional class to clinical status (activity tolerance) and metabolic equivalents (METs) achievable on treadmill testing.

The musculoskeletal organ system enjoys no such well-accepted, validated scales.  There are, however, a number of organ-specific, self-reporting functional assessment tools currently in use.  Consistent and standardized self-report data is provided by these functional tools. Descriptive and analytical applications of these assessment devices can generate valid impairment rating.  Scores can be ordered by rank into “no deficit; mild; moderate; severe; and extreme” categories:  quantifying a patient’s pain and functional loss.

Unfortunately, the Sixth Edition has failed to address the paramount problem of impairment assessment.  Functional losses, in terms of ADLs, are simply not manifest in the impairment ratings themselves.  The validity of impairment ratings will not improve until direct measurement of functional losses in terms of ADLs truly becomes the common metric, as distinct from the largely rhetorical role it now plays on the margins of impairment ratings.

FOOTNOTES
1. www.impairments.comp/useofamaguides.htm.
2. FECA 5 U.S.C. 8107.
3. Section 8(c) (1)-(20) of the LHWCA.
4. Florida Statutes 627.737(2)(1995).
5. Guide to the Evaluation of Permanent Impairment Sixth Edition, p. 21.
6. Ibid., Preface, p. iii, iv.
7. Ibid., Preface, p.iv.
8. Ibid., p. 5.
9. Guide to the Evaluation of Permanent Impairment Fifth Edition, p.600.
10. Guide to the Evaluation of Permanent Impairment Sixth Edition, p.9-12.
11. Ibid., p.16.
12. Ibid., p. 20.
13. Thanks go to Jim McCarthy, WILG member from New York, for this item.
14. Guide to the Evaluation of Permanent Impairment Sixth Edition, p.16.
15. Ibid., p. 615.
16. Ibid., p. 5.
17. For The Defense: Misuse and Abuse, AMA Guides to the Evaluation of Permanent Impairment, p. 22.
18. Ibid., p. 32.
19. Ibid., p. 29.
20. Ibid., p. 29.
21. Disability Evaluation, Demeter and Anderson , Chapter 13, Dr. Tom Mayer, p. 127-135.
22. Cottrell v. W.C. Division, Claim No. 92-66811 (d/o/i 7/7/91).
23. Guide to the Evaluation of Permanent Impairment Sixth Edition, p. 39.
24. Ibid., p. 43.
25. Texas Workers’ Compensation Comm’n. v. Garcia 893 S.W.2d 504, ( Tex. 1995).
26. Davis v. B.F. Goodrich 826 P. 2d 587 ( Okla. 1992).
27. Brown v. Campbell Bd. of Educ., 915 S.W. 2d 407, ( Tenn. 1995).
28. McCabe v. North Dakota Workers Compensation Bureau, 1997, ND 145, 567 N.W. 2d 201; West Virginia Ct. in Repass 212 W.Va 86; International Association of Plumbing and Mechanical Officials v. California Building Standards Commission, 555 Cal. App. 4th 245. Thanks go to Sue Ann Howard, WILG member from West Virginia, for this insight.
29. Guide to the Evaluation of Permanent Impairment Sixth Edition, p.615.
30. Ibid., p.10.
31. Ibid., p.15.
32. Ibid., p. 9, 10.

© Copyright 2008 by Workers Injury Law & Advocacy Group. All rights reserved. Reprinted with permission.