Autonomic Dysfunction in Amyotrophic Lateral Sclerosis – A Case-Control Study

Abstract

Introduction. This study aimed to explore autonomic nervous system involvement in amyotrophic lateral sclerosis (ALS) pa- tients by evaluating sympathetic skin response (SSR). Materials and Methods. The study included 35 sporadic (ALS) patients (cases), and 35 healthy age and sex-matched participants (controls) aged <60 years. SSR was recorded in the electrophysiology lab of the Neurology Department of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh. Patients with diseases associated with peripheral or autonomic neuropathy were excluded. Prolonged latency (delayed SSR) or an ab- sent response was considered abnormal SSR. Results. SSR was found to be abnormal in 17 (48.6 %) ALS cases, with an absent response in the upper limbs of six cases (17.1%). Abnormal SSR was more prevalent in the lower limbs, with 33 (94.3%) and 20 (57.1%) cases having a delayed or absent response, respectively. In comparison, SSR was normal in all control participants (P-value <0.05). Abnormal SSR was significantly more common in the lower limbs of ALS cases with bulbar palsy than those without bulbar palsy (P-value=0.04). There was no association of SSR with disease severity and duration. Conclusion. ALS is significantly associated with abnormal SSR, indicating autonomic nervous system involvement. There could also be an associa- tion between bulbar palsy and abnormal SSR among ALS patients. Further studies should be carried out to determine the as- sociation of abnormal SSR with disease severity, duration, and type.