A new clinical scale to grade the impairment of median nerve in carpal tunnel syndrome

Objective: In carpal tunnel syndrome (CTS) distribution of paresthesias is related to the degree of the nerve impairment. To improve the clinical ability in detecting the damage severity, we have introduced the criteria "distribution of paresthesias" in a previous clinical scale: the historical-objective scale (Hi-Ob). Methods: We evaluated 100 consecutive patients (40 bilateral CTS) to validate a five stages clinical scale: the Historical-objective-distribution based scale (Hi-Ob-Db). We compared the Hi-Ob-Db with a validated neurophysiological classification and with the Boston Carpal Tunnel Questionnaire (BCTQ). The BCTQ evaluates two domains, one assessing symptoms (SYMPT = patient-oriented symptom), and the other analysing "functional status" (FUNCT = patient-oriented function). Results: The positive correlation between the Hi-Ob-Db and neurophysiological findings (p < 0.001, r:0.79) was stronger than correlation between the Hi-Ob and the neurophysiological classification (p < 0.001, r:0.74). A linear correlation between the Hi-Ob-Db and the patient-oriented scores was observed, respectively FUNCT (p < 0.003, r:0.38) and SYMPT (p < 0.002, r:0.30). Conclusions: The Hi-Ob-Db is a clinical scale which correlates with the neurophysiological impairment of the median nerve and with patient-oriented findings in patients with CTS. Significance: The new scale may be useful in routine examination and for scientific purposes. © 2010 International Federation of Clinical Neurophysiology.