Autonomic dysfunction in patients with Huntington's disease: Evidence from standardized cardiovascular reflex testing.

BackgroundAutonomic dysfunction has been reported in Huntington's disease (HD), but its extent and mechanisms remain unclear. This study aimed to evaluate autonomic function using standardized cardiovascular autonomic reflex tests (CRTs) in a cohort of genetically confirmed HD patients.MethodsIn this single-center, cross-sectional study, we assessed 16 patients with manifest HD using head-up tilt test (HUTT), Valsalva maneuver (VM), deep breathing test, cold face test, and handgrip test, all performed under continuous blood pressure (BP) and heart rate (HR) monitoring. Age- and sex-matched healthy controls (HC) were included for comparison.ResultsBased on medical history, 56% of HD patients reported symptoms of orthostatic intolerance while standing. During HUTT, they showed a significant reduction in ΔBP. BP overshoot during VM was also significantly reduced. HR responses and BP changes did not differ significantly between groups across all other maneuvers. When stratified by disease stage, parasympathetic indices were lower in later-stage patients.ConclusionsHD patients exhibited subclinical adrenergic abnormalities on CRTs, with initially preserved cardiovagal control, a pattern compatible with central autonomic involvement and possible progressive impairment of both sympathetic and parasympathetic systems over time.