Demonstration of sympathetic dysfunction in patients with obstructive sleep apnea syndrome by measuring sympathetic skin responses from the neck.

OBJECTIVE: We aimed to study the sympathetic sudomotor responses via the sympathetic skin responses (SSR) from bilateral hands and right and left sides of the neck in patients with obstructive sleep apnea syndrome (OSAS).

METHODS: A total of 31 patients with OSAS diagnosed by whole-night polysomnography and 18 healthy volunteers were consecutively enrolled into this prospective study.

RESULTS: The SSRs from hands were not obtained in two patients with OSAS (6.4%) and in one volunteer (5.5%); the attainability of SSRs from hands was similar between patients and healthy controls (p = 0.698). The SSRs from neck were not obtained in 22 patients with OSAS (70.9%), but only in two healthy volunteers (11.1%, p <0.001). The mean amplitudes of SSRs from both right and left sides of neck were significantly lower in patients with OSAS than those in controls (p <0.001). After effective treatment of OSAS, the SSRs from hands were obtained in all patients (100% vs 93.6% before treatment, p = 0.560). The attainability of SSRs from bilateral sides of the neck was significantly improved after treatment (80%) in compared to before treatment (29.1%, p <0.001). The amplitudes of SSRs obtained from the neck were also significantly increased after treatment (p <0.004).

CONCLUSIONS: Our results show that there is sympathetic dysfunction in OSAS, which could be demonstrated by sudomotor response abnormalities from neck area and reversed following effective treatment of OSAS. SSR studies from the neck area may therefore be accepted as an easy and effective method for demonstrating the sympathetic dysfunction in OSAS and for monitoring the efficacy of OSAS treatment.