RESUMEN
INTRODUCTION: Carpal tunnel syndrome (CTS) is the most common of all focal neuropathies. Its diagnosis is based on a neurophysiological study of the thick motor and sensory fibres in patients with a characteristic clinical picture, although sometimes, in mild cases, this study does not detect the abnormalities. The decision was made to evaluate the small-calibre sympathetic fibres by means of cutaneous-plantar reflex (CPR) in patients with different degrees of idiopathic CTS. SUBJECTS AND METHODS: The study involved 54 cases -15 males and 39 females with CTS- and 15 healthy volunteer controls. The cases were divided into three groups: those with only positive clinical features; those with clinical features and alteration of sensory conduction; and those with clinical features, alteration of sensory and motor conduction, and axonal loss. The CPR was obtained by means of the usual technique (which we modified), involving stimulation of the median nerve in the wrist and recording the response in the contralateral hand. Two successive responses were processed with an interval of more than one minute between them. Special attention was paid to controlling the baseline and sweating. A descriptive statistical inference and correlation analysis was performed. RESULTS: A decrease in amplitude of the response was observed in patients with CTS, with shorter latencies in women and a good correlation between the latencies of the first and the second response. No significant differences were observed in the other parameters that were studied. CONCLUSION: Studying the CPR can provide complementary data in the evaluation of CTS.