Sudomotor dysfunction is frequent and correlates with disability in Friedreich ataxia

•Cardiovascular dysautonomia is not common in Friedreich’s ataxia (FRDA).•Sudomotor dysfunction is frequent and related to peripheral damage in FRDA.•QSART correlates with ataxia severity and is a promising biomarker for FRDA. To evaluate autonomic symptoms and function in Friedreich’s Ataxia (FRDA). Twenty-eight FRDA patients and 24 controls underwent clinical/electrophysiological testing. We employed the Friedreich’s Ataxia Rating Scale (FARS) and the Scales for Outcomes in Parkinson’s Disease: Autonomic Questionnaire-SCOPA-AUT to estimate the intensity of ataxia and autonomic complaints, respectively. Cardiovagal tests and the quantitative sudomotor axonal reflex, Q-SART, were then assessed in both groups. In the patient group, there were 11 men with mean age of 31.5 ± 11.1 years. Mean SCOPA-AUT score was 15.1 ± 8.1. Minimum RR interval at rest was shorter in the FRDA group (Median 831.3 × 724.0 ms, p 0.05). Sweat responses were significantly reduced in patients for all sites tested (forearm 0.389 × 1.309 µL; proximal leg 0.406 × 1.107 µL; distal leg 0.491 × 1.232 µL; foot 0.265 × 0.708 µL; p value