NEUROPHYSIOLOGICAL CLASSIFICATION OF CARPAL-TUNNEL SYNDROME - ASSESSMENT OF 600 SYMPTOMATIC HANDS

Following the AAEM electrodiagnostic guidelines, we developed a neurop hysiological classification of carpal tunnel syndrome (CTS). Sixhundre d hands with clinical CTS (mean age 51.4 yr., female/male ratio 5.5/1, right/left ratio 1.8/1) were prospectively evaluated and divided into six classes of severity only on the basis of median nerve electrodiag nostic findings: extreme CTS (EXT - absence of thenar motor responses) , severe CTS (SEV - absence of sensory response and abnormal distal mo tor latency - DML), moderate CTS (MOD - abnormal digit-wrist conductio n and abnormal DML), mild CTS (MILD - abnormal digit-wrist conduction and normal DML), minimal CTS (MIN - exclusive abnormal segmental and/o r comparative study), and negative CTS (NEG - normal findings at all t ests) Using this neurophysiological classification, the CTS groups app eared normally distributed (EXT 3% of cases, SEV 14%, MOD 36%, MILD 24 %, MIN 21%, NEG 3%), and the age of patients and clinical findings app eared to be related to neurophysiological abnormalities. Significant d ifferences in median neurophysiological parameters not included in the classification (such as palm-wrist sensory conduction velocity) were observed in the different CTS groups. The analysis of the groups showe d that: 1) the majority of advanced cases (SEV and EXT) occurred in ol der patients (60-80 years), 2) most of the milder cases (MIN and MILD) occurred in young female patients. The aim of this study was to stand ardise the neurophysiological evaluation of CTS.