Since its inception more than six decades ago, the AMA Guides to the Evaluation of Permanent Impairment, ( AMA Guides ), has become internationally accepted as a global benchmark and is used in the United States, Canada, certain European countries, the Middle East, Australia, New Zealand, and Southern Africa, as well as by the United Nations. When the AMA Guides, Sixth Edition, adopted the terminology and conceptual framework of disablement developed by the World Health Organization, this paradigm shift let to an increase in the worldwide influence and use of the AMA Guides . In the United States, the AMA Guides is used primarily in state and federal workers’ compensation systems and sometimes in automobile casualty and personal injury arenas. Most workers’ compensation jurisdictions across Canada use the AMA Guides formally by statute or regulation, or they accept its use informally as a standard tool to rate impairment. In Australia, the AMA Guides is used in both federal and individual state or territory compensation schemes for personal injuries that arise from work, as well as motor vehicle accidents (a table presents uses of the AMA Guides in Australian jurisdictions). New Zealand uses the AMA Guides, Fourth Edition, and the ACC User Handbook to the AMA “Guides to the Evaluation of Permanent Impairment,” Fourth Edition. The AMA Guides is used in Hong Kong to evaluate all types of damages for personal injury claims and also is referenced in Southern Africa, Europe, and countries in the Middle East.

An evaluator's failure to recognize illness behavior and to adjust for its effect on symptom presentation can lead to erroneous conclusions regarding impairment or disability; here the authors review the associated phenomena of somatization, disorders that arise from it, and factors that contribute to somatization. Somatization is an individual's unconscious use of the body or bodily symptoms for psychological purposes or psychological gain. As the AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ), Sixth Edition, notes, somatization is a “tendency to experience and report somatic complaints (physical symptoms) in response to psychosocial stress and seek health care services for them.” The AMA Guides also advises evaluators that “exclusion or inclusion of somatization disorder, factitious disorder, and/or malingering must be done with care.” A table lists developmental factors that may dispose to somatization (eg, somatizers are present in the family of origin, or coping mechanisms other than illness behavior are absent or unacceptable); a second table compares disorders that may involve somatization. Somatization is prevalent in clinical practice and is likely to occur with equal, or higher, frequency in the evaluation setting. The presence of somatization distorts symptom presentation and can exert a confounding effect on impairment assessment methodologies that rely on the accuracy of patients’ self-presentations.

Under California Labor Code Section 3212.1, firefighters, forestry and fire protection workers, peace officers, and first responders receive a potentially rebuttable presumption of compensability for certain conditions, including cancer and leukemia. This case example illustrates the need for accurate clinical, causation, apportionment, and impairment assessments that are based on the facts, current science, and appropriate use of the AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ). A retired California firefighter in his mid-sixties presented for an impairment evaluation for the sequelae of his colon cancer; six years earlier, he was diagnosed with stage 1 colorectal cancer and received neoadjuvant chemotherapy and radiation therapy, followed by surgical resection with a diverting colostomy and take-down surgery. He is morbidly obese (body mass index, 45) and has hypertension. He reported fecal frequency, urgency, and incontinence and stated he had problems with erectile dysfunction (ED) before his diagnosis of colon cancer, but after diagnosis and treatment the problem worsened to impotence. The author presents impairment assessments of this case example according to the AMA Guides, Fifth Edition vs the Sixth Edition. According to the fifth edition, this individual's impairment for lower gastrointestinal tract impairment is 17% whole person impairment (WPI), and this is combined with 5% WPI for ED, resulting in 21% WPI. According to the sixth edition, the lower gastrointestinal tract impairment of 14% is combined with 5% WPI for ED, leading to an 18% WPI.

In the United States, the AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ) is used in state and federal workers’ compensation systems and in automobile casualty and personal injury arenas. The AMA Guides is used in similar ways internationally. Most workers’ compensation jurisdictions in Canada use the AMA Guides formally by statute or regulation or accept its use informally as a standard tool to rate impairment. In Australia, the AMA Guides is used in both federal (Australian Commonwealth) and individual states’ (or territories’) compensation schemes; two tables show how almost all states in Australia have legislated various editions of the AMA Guides for use in workers’ compensation and motor traffic accident compensation schemes. New Zealand's Accident Compensation Commission (ACC) previously used the AMA Guides, Fourth Edition; beginning in July 2011 ACC uses the sixth edition. Hong Kong uses the AMA Guides as a reference in evaluating workers’ compensation and motor vehicle claims; Malaysia uses the AMA Guides officially in adjudication; and impairment rating in Asian countries such as Taiwan, Korea, and Singapore are influenced by the philosophy and principles of the AMA Guides . South Africa uses the AMA Guides, Sixth Edition, to determine serious injury, and other editions are used in South Africa's workers’ compensation schemes. Many countries in Europe and the Middle East use the AMA Guides as a reference for determining impairment and in workers’ compensation and social welfare schemes.

In the AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ), Sixth Edition, the chapter on the upper extremities is the longest and most complex, which reflects the complexities of the upper limb and the type of injuries encountered. This chapter incorporates the following changes: The International Classification of Functioning, Disability, and Health (ICF) Model of Functioning and Disability, developed by the World Health Organization, is used to provide a common basis for the description of human functioning and impairments. The principles of assessment have been simplified and clarified. Specific diagnosis-based rating tables for the most common injuries and diagnoses have been added, and an extensive discussion shows the definition of impairment classes and corresponding ranges of impairment for upper and lower extremities. A table and accompanying diagnosis-based impairment example provide examples of upper extremity diagnoses and associated class definitions and default impairment values. The physical examination has been simplified, and functional assessment is provided through focused history-taking, including information about activities of daily living and a functional assessment tool. The criteria for diagnosis of complex regional pain syndrome have been updated for consistency with current standards and other chapters. Among other modifications, the approach to entrapment neuropathy (eg, carpal tunnel syndrome) has changed, and only electrodiagnostically confirmed entrapment cases are ratable.

The AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ), Sixth Edition, was published in December 2007 and is the result of efforts to enhance the relevance of impairment ratings, improve internal consistency, promote precision, and simplify the rating process. The revision process was designed to address shortcomings and issues in previous editions and featured an open, well-defined, and tiered peer review process. The principles underlying the AMA Guides have not changed, but the sixth edition uses a modified conceptual framework based on the International Classification of Functioning, Disability, and Health (ICF), a comprehensive model of disablement developed by the World Health Organization. The ICF classifies domains that describe body functions and structures, activities, and participation; because an individual's functioning and disability occur in a context, the ICF includes a list of environmental factors to consider. The ICF classification uses five impairment classes that, in the sixth edition, were developed into diagnosis-based grids for each organ system. The grids use commonly accepted consensus-based criteria to classify most diagnoses into five classes of impairment severity (normal to very severe). A figure presents the structure of a typical diagnosis-based grid, which includes ranges of impairment ratings and greater clarity about choosing a discreet numerical value that reflects the impairment.

Chronic fatigue syndrome (CFS) is a term applied to individuals who report severe chronic fatigue out of proportion to their efforts, but the AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ), Fourth and Fifth Editions, are clear that no ratable impairment is linked to CFS. Chronic fatigue is not synonymous with CFS; only a small fraction of persons who present with chronic fatigue symptoms meet the criteria for CFS; and CFS, like fibromyalgia and multiple chemical sensitivity, is poorly understood. CFS may be associated with disability but primarily is based on psychological rather than physical symptoms. No tests confirm the diagnosis of CFS, and routine laboratory testing is reserved for excluding other medical conditions. CFS is an illness without a disease and often is characterized by illness behavior expressed as somatization. To date, no convincing evidence supports the notion that CFS is an infectious, neuroendocrine, or immunologic disorder. Thus, sophisticated behavioral assessment is critical and may include a fatigue rating scale, a depression scale, and psychological and personality inventories. No specific treatment has been recommended for CFS treatment, but cognitive and behavioral interventions may be useful to address psychological symptoms; medication is reserved for specific symptoms indicative of depression or anxiety.

The AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ), Fifth Edition, is available and includes numerous changes that will affect both evaluators who and systems that use the AMA Guides. The Fifth Edition is nearly twice the size of its predecessor (613 pages vs 339 pages) and contains three additional chapters (the musculoskeletal system now is split into three chapters and the cardiovascular system into two). Table 1 shows how chapters in the Fifth Edition were reorganized from the Fourth Edition. In addition, each of the chapters is presented in a consistent format, as shown in Table 2. This article and subsequent issues of The Guides Newsletter will examine these changes, and the present discussion focuses on major revisions, particularly those in the first two chapters. (See Table 3 for a summary of the revisions to the musculoskeletal and pain chapters.) Chapter 1, Philosophy, Purpose, and Appropriate Use of the AMA Guides, emphasizes objective assessment necessitating a medical evaluation. Most impairment percentages in the Fifth Edition are unchanged from the Fourth because the majority of ratings currently are accepted, there is limited scientific data to support changes, and ratings should not be changed arbitrarily. Chapter 2, Practical Application of the AMA Guides, describes how to use the AMA Guides for consistent and reliable acquisition, analysis, communication, and utilization of medical information through a single set of standards.

The AMA Guides to the Evaluation of Permanent Impairment, ( AMA Guides ), Fourth Edition, notes that individuals may consciously exaggerate the symptoms of a disorder in the clinical or impairment evaluation setting, an activity that is associated with the process of somatization. This article reviews the phenomena of somatization, its magnitude, factors that contribute, and somatizing disorders themselves. Somatization is characterized by the propensity to experience and report somatic symptoms that have no pathophysiologic explanation, to misattribute them to disease, and to seek medical attention for them. Reported symptoms could result from organic disease—which is precisely the point because somatizing patients choose symptoms, consciously or not, that will be taken as evidence of real, physical disease. The prevalence of somatization reportedly ranges from 5% to 60% and varies with the medical specialty and the clinical setting. Studies have reported that in 25% to 50% of all primary care encounters, physicians found no significant objective cause to explain the presenting symptoms. The somatization process contributes to somatoform disorders, which are mental disorders and are not intentionally produced or feigned. A table compares three types of somatizing disorders: somatoform disorders, factitious disorders, and malingering. The presence of somatization distorts symptom presentation and can confound assessment methodologies, but the AMA Guides instructs that impairment is rated on the basis of objective findings, not solely on subjective complaints.