AMA Guides® Newsletter - Issue Archive

Articles

1. Global Assessment of Functioning

   Norma Leclair, Steven Leclair, Robert Barth

   Pages 1–4, 8

   DOI: 10.1001/amaguidesnewsletters.2007.NovDec01

   Abstract

   The Global Assessment of Functioning (GAF) is part five of the multiaxial diagnostic system for mental disorders outlined in the Diagnostic and Statistical Manual for Mental Disorders, Fourth Edition–Text Revised (DSM-IV-TR). The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) notes the use of DSM-IV-TR in rating an individual's global functional capacity, which, like disability, is related directly to the effects of impairments. The AMA Guides, Fourth and Fifth Editions, do not provide numeric psychiatric impairment, and shortcomings plague the use of GAF to define disability—but even so, authorities ranging from the State of California to the Veterans Administration rely on GAF scores. A table shows the 100-point scale Global Assessment Scale in which higher scores indicate better functioning. The GAF has been modified to address deficiencies; a decision tree has been added and is summarized; and the editor of DSM-IV-TR has developed a computerized version that reportedly improves reliability and validity. Evaluators should bear in mind that the GAF helps evaluate the individual's functioning in three areas: psychological, social, and occupational (including the activities of daily living). The resulting score facilitates the creation of a treatment plan, evaluates its effectiveness, and predicts outcomes, but evaluators should be aware of its significant limitations.
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2. Clinical Update: Understanding Causation: An Example Using Carpal Tunnel Syndrome

   J. Mark Melhorn

   Pages 5–8

   DOI: 10.1001/amaguidesnewsletters.2007.NovDec02

   Abstract

   Medical evidence is drawn from observation, is multifactorial, and relies on the laws of probability rather than a single cause, but, in law, finding causation between a wrongful act and harm is essential to the attribution of legal responsibility. These different perspectives often result in dissatisfaction for litigants, uncertainty for judges, and friction between health care and legal professionals. Carpal tunnel syndrome (CTS) provides an example: Popular notions suggest that CTS results from occupational arm or hand use, but medical factors range from congenital or acquired anatomic structure, age, sex, and body mass index, and perhaps also involving hormonal disorders, diabetes, pregnancy, and others. The law separately considers two separate components of causation: cause in fact (a cause-and-effect relationship exists) and proximate or legal cause (two events are so closely related that liability can be attached to the first event). Workers’ compensation systems are a genuine, no-fault form of insurance, and evaluators should be aware of the relevant thresholds and legal definitions for the jurisdiction in which they provide an opinion. The AMA Guides to the Evaluation of Permanent Impairment contains a large number of specific references and outlines the methodology to evaluate CTS, including both occupational and nonoccupational risk factors and assigning one of four levels of evidence that supports the conclusion.
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3. Case Study: Cervical Spine Apportionment

   Christopher R. Brigham, Aimee McEntire

   Pages 9–11

   DOI: 10.1001/amaguidesnewsletters.2007.NovDec03

   Abstract

   Impairment apportionment refers to the distribution or allotment of impairment to different factors such as pre-existing injury, illness, or impairment. The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) provides instructions about calculating impairment ratings and advises concurrent consultation of specific state laws (eg, the state of California apportions disability differently than does the Longshore and Harbor Workers Act. A case example highlights some of the complexities of cervical spine apportionment. A 55-year-old man sustained a work-related cervical spine injury that aggravated pre-existing cervical pathology. The patient underwent anterior cervical discectomy and decompression, foraminotomies, C3-4 and C4-5, and a two-level anterior cervical interbody arthrodesis; the postoperative diagnosis was two level disc herniation, stenosis, and disc degeneration. The article discusses the Diagnosis-related estimate (DRE) vs the range-of-motion method (ROM). The DRE method is most widely used in the AMA Guides, but in certain specified situations, including a multilevel fusion such as that in the clinical example, the ROM method must be used. Because of the significant difference in values derived from the DRE and ROM methods, evaluators must be careful to apportion impairment in accordance with the method that served as the basis for the final rating (ie, the ROM method in this example). Apportionment becomes more complex when one considers the etiology of the underlying disease.
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