Peripheral autonomic involvement in the carpal tunnel syndrome

Abstract

The sympathetic skin response (SSR), evoked from the middle finger of both hands by electrical stimuli to the median nerve (MN) at the wrist, was studied in 21 patients with bilateral carpal tunnel syndrome (CTS) and in 16 patients with monolateral CTS (14 at the right and 2 at the left side) without clinical signs of autonomic involvement. In monolateral and bilateral CTS there was a decrease in the SSR areas of both sides. In monolateral CTS the decrease was greater contralaterally to the lesion. A decrease in the SSR in CTS generally indicates a local blockade of sympathetic nerve excitability due to MN entrapment. Contralateral reduction of the sympathetic response suggests an involvement of the efferent pathway of the autonomic reflex far from the lesion at the wrist. However, dispersion of the excitement over a long distance and throughout numerous synaptic connections may affect contralateral more than homolateral SSR excitability. Finally, sympathetic damage in CTS is in accord with the anatomofunctional correlation (in the peripheral nerve and ganglia) between somatic sensory, which were most markedly involved in our patients, and sympathetic afferent nerve fibers.

Skin temperature in the dorsal hand of office workers and severity of upper extremity musculoskeletal disorders

“…The skin sympathetic response (SSR) was absent in 23% of CTS patients in one study (Reddeppa et al 2000); the more severe case group (as defined by electrophysiological parameters) had non-significantly smaller mean SSR amplitudes in both median and ulnar nerves. Reduced SSR area responses have been observed with CTS as well (Caccia et al 1993;Reddeppa et al 2000). An abnormal SSR was also evident in the affected versus unaffected arm in lateral epicondylitis (Smith et al 1994).…”

Sympathetic skin response in primary Raynaud’s phenomenon

“…However, in detailed SSR studies, Toyokura and Murakami [23,24] have shown good reproducibility and reliability of mean latency and maximum amplitude of response in normal subjects. In our study, we measured mean latency and shortest latency in each subject; in line with Caccia et al [2], we measured area rather than amplitude peak-to-peak, because it makes quantification of total sympathetic excitability of the nerve more accurate. Since some studies showed that age and height may influence SSR [17], controls were matched for height and age with the patients.…”

“…For each recording site (palm and fingers), the following parameters were measured in patients and controls: (1) mean latency and area of 12 consecutive responses, excluding the first [23,24]; automatic average was avoided because latency and morphology vary from one recording to the next and phase cancellation is possible [28]; (2) latency of the shortest response; (3) area of the largest response. Grand means (mean of means) of (1) and means of (2) and (3) were also calculated in patients and controls.…”

An assessment of the sympathetic function within the hand in patients with carpal tunnel syndrome

“…There have been several sympathetic skin response studies in CTS patients and their results are not consistent: reduced or normal sympathetic activity was reported in the majority (Caccia et al, 1993;Kanzato et al, 2000;Mondelli et al, 2000;Reddeppa et al, 2000;Sener et al, 2000). Vasomotor dysfunction in digital arteries was found in CTS patients in two studies, which employed the Doppler technique (Galea et al, 2006;Wilder-Smith et al, 2003).…”

“…Moreover, it is not clear whether compression results in an increase or inhibition of sympathetic activity, which translates into different clinical effects: Raynaud phenomenon, blanching and excessive sweating in the former, and dryness as well as warmness of the hand in the latter. The spectrum of these features in CTS patients as reported in the literature is wide and includes both situations (Caccia et al, 1993;Mondelli et al, 2000;Sener et al, 2000;Verghese et al, 2000).…”