Sympathetic skin response and heart rate variability in patients with Huntington disease

Objective: To examine the autonomic nervous system functions in patients with Huntington disease. Background: Although patients with Huntington disease frequently experience vegetative symptoms, it is not clear if there is dysfunction of the autonomic nervous system. Methods: Sympathetic skin response (SSR) latency and amplitude from both palms and soles and R-R (heart rate) interval variation (RRIV) at rest and during the Valsalva maneuver were examined in 22 patients and 21 age-matched controls. Unified Huntington's Disease Rating Scale scores were determined in all the patients. Results: Our data are reported as means +/- SEMs. The SSR latencies in patients (mean palm latency, 1835.8 +/- 110.7 milliseconds; mean sole latency, 2625.3 +/- 226.9 milliseconds) were prolonged compared with controls (mean palm latency, 1359.5 +/- 28 milliseconds [P < .01]); mean sole latency, 2038.1 +/- 44.9 milliseconds [P < .01]) and amplitudes in patients (moan amplitude, 1063.1 +/- 237.7 mu V) were smaller compared with controls (mean amplitude, 1846.3 +/- 251.2 mu V [P < .05]). The RRIV in patients both at rest (mean RRIV in patients, 3.7% +/- 0.4% vs controls, 9.7% +/- 0.6% [P < .01]) and during the Valsalva maneuver (mean RRIV in patients, 6.3% +/- 1.6% vs controls, 14.5% +/- 1.2% [P < .01]) was lower compared with controls. Furthermore, the prolonged SR latencies, smaller amplitudes, and lower RRIV in patients compared with controls closely correlated with the various components of the Unified Huntington's Disease Rating Scale scores (total behavior score and SSR latency, R = 0.6 [P < .01]; total behavior score and SSR amplitude, R = -0.5 [P < .05]; total behavior score and RRIV, R = -0.4 [P < .05]; verbal fluency and SSR latency, R = -0.5 [P < .05]; verbal fluency; and SSR amplitude, R = 0.5 [P < .05], verbal fluency and RRIV, R = 0.5 [P < .05], total functional capacity and SSR latency, R = -0.6 [P < .01]; total functional capacity and SSR amplitude, R = 0.5 [P < .05]). Conclusion: These results suggest that there is autonomic nervous system dysfunction in patients with Huntington disease.