Differentiation of Autonomic Dysfunction in Multiple System Atrophy Sub types and Idiopathic Parkinson's Disease

Objective: This study aimed to describe autonomic dysfunction in Multiple System Atrophy (MSA) patients and compare this with Idiopathic Parkinson’s disease (IPD) patients and healthy controls. Background: MSA is a neurodegenerative extrapyramidal syndrome with autonomic dysfunction forming the cornerstone of diagnosis. It is of two sub types, MSA-cerebellar type (MSA-C) and MSA-parkinsonism (MSA-P) type. There is limited data on differences in autonomic features between the two subtypes. Design/Methods: We conducted an observational cross-sectional study in a tertiary care center in India which enrolled forty eight MSA-P, fifty two MSA-C, fifty IPD patients and fifty healthy controls. A self-administered questionnaire (SCOPA-Aut) was filled by participants. All participants underwent cardiovascular autonomic testing including deep breathing tests (change in heart rate, E:I ratio), Valsalva ratio, hand-grip, cold pressor and postural tests (change in systolic blood pressure, 30: 15 ratio). Disease status was assessed by Unified MSA Rating Scale, Hoehn and Yahr stage and Unified Parkinson’s Disease Rating scale part III. Results: We studied MSA-P (48 participants; age 63.6 ± 9.7 years; UMSARS 45± 16.5), MSA-C (50 participants; 58 ± 8.1 years; UMSARS 44± 12.8), IPD (50 participants; 57.6±6.7 years) and healthy controls (50 participants; 58±8.0 years). SCOPA-Aut revealed that MSA patients scored poorly versus control in gastrointestinal, urinary, cardiovascular and sexual autonomic domains and from IPD in gastrointestinal, urinary and cardiovascular domains. MSA subtypes did not differ in symptomatology or autonomic function. Between MSA and IPD, change in heart rate on standing and deep breathing, and rise in diastolic blood pressure with cold pressor test were significantly different. Conclusions: MSA patients report autonomic dysfunction frequently although the two subtypes do not differ. In gastrointestinal, urinary and cardiovascular domains, these are more severe compared to IPD. Heart rate variability and cold pressor testing distinguishes IPD and MSA. This may enable clinicians to differentiate patients with MSA from IPD. Disclosure: Dr. Garg has nothing to disclose. Dr. Srivastava has nothing to disclose. Dr. Jaryal has nothing to disclose. Dr. Pandey has nothing to disclose. Dr. Rajagovindan has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Biogen. Dr. Rajagovindan holds stock and/or stock options in Biogen. Dr. Pandit has nothing to disclose. Dr. Vibha has nothing to disclose. Dr. Shukla has nothing to disclose. Dr. Prasad has nothing to disclose.