RESUMO
OBJECTIVE: Amyotrophic 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). METHODS: Thirty-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. RESULTS: A 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). CONCLUSION: ESC is a non-invasive, fast and quantitative method suitable for assessing sudomotor function. ALS patients revealed a decreased function in upper and lower extremities. SIGNIFICANCE: Sudomotor dysfunction is part of the ALS manifestations.