Part 1 of this series examined many of the rules in the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Sixth Edition, regarding rating nerve entrapment or focal neuropathies; the current article, part 2, examines how to read and match the findings in an electrodiagnostic report to the criteria in Appendix 15-B, Electrodiagnostic Evaluation of Entrapment, as explained in Section 15.4f, and determine the severity of the test findings as listed in Table 15-23. Physicians who perform nerve conduction studies often use their own definitions of mild, moderate, and severe; these definitions are not standardized and frequently differ from the electrophysiologic definitions used in the AMA Guides, Sixth Edition. When examiners rate focal entrapment neuropathy, they must match data from the electrodiagnostic report to the criteria in Appendix 15-B, and a figure shows a hypothetical motor nerve conduction report for a case that shows both mild neuropathy (conduction delay) of the median nerve at the wrist (carpal tunnel syndrome) and severe neuropathy (axon loss) of the ulnar nerve at the elbow (cubital tunnel syndrome). If both fibrillations and positive waves are seen in the same muscle, the reviewer can be more confident that other electromyographic potentials were not misinterpreted as fibrillations. Prepared with the results of electrodiagnostic studies, the evaluator can work through the steps of history, physical findings, and functional scale to determine the final upper limb impairment according to the AMA Guides.

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