Assessment of sympathetic sudomotor function in amyotrophic lateral sclerosis with electrochemical skin conductance

Abstract

ObjectiveAmyotrophic lateral sclerosis (ALS) is now recognized as a multisystem neurodegenerative disorder, comprising autonomic dysfunction. We aimed to assess sudomotor function in ALS by measuring the electrochemical skin conductance (ESC). MethodsThirty-one ALS patients [median age of 62 years (1st-3rd interquartile range – IQR, 56–72), male 71%] were prospectively compared with 29 healthy controls, matched for age and sex. We analysed ESC results from hands and feet, bilaterally. ResultsA total of 120 ESC recordings were obtained. Hands and feet ESC measurements were significantly lower in patients compared with controls [64 μS (1st-3rd IQR, 57–58) versus 78 μS (1st-3rd IQR, 70.5–84), p < 0.001 and 76 μS (1st-3rd IQR, 68–83) versus 81 μS (1st-3rd IQR, 78–86), p = 0.008, respectively]. In ALS group, no differences were observed between spinal and bulbar-onset forms for hands and feet results (p > 0.05). Hands and feet ESC measurements did not correlate also with disease duration, total ALSFRS-R scale, or ALSFRS-R progression rate (all p > 0.05). ConclusionESC is a non-invasive, fast and quantitative method suitable for assessing sudomotor function. ALS patients revealed a decreased function in upper and lower extremities. SignificanceSudomotor dysfunction is part of the ALS manifestations.