P15. Measures of autonomic dysfunction in early-motor Parkinson’s disease

Abstract

Aims Symptoms of autonomic dysfunction are increasingly recognized as part of the clinical spectrum in Parkinson’s disease (PD), often causing considerable distress. The extent and disease burden of autonomic nervous system (ANS) dysfunction in PD patients has been studied extensively, however the relationship between ANS and motor symptoms as well as their pathoaetiology is not well understood. This cross-sectional study is aimed at investigating the extent of ANS dysfunction in the early-motor phase of PD by comparing patients to control (Ctrl) subjects in the absence of potentially interfering medication. Methods 16 PD patients (Hoehn & Yahr 2) and 11 sex- and age-matched Ctrl subjects without history of gastrointestinal (GI) disease, diabetes mellitus and antihypertensive treatment were examined in the morning of a single study visit after an overnight-fast in the strict absence of medication influencing GI motility or blood-pressure (bp) regulation. Long-acting dopaminergic medication (dopamine agonists, extended release L-Dopa) was stopped 36 h, standard L-Dopa 12 h prior to testing. Objective Schellong test, Finapres heart rate (HR) variability assessment, 7d-blood pressure recording and C13-octanoate gastric emptying breath test were performed and subjective symptoms assessed using questionnaires. Results Groups were well matched for age (PD 66.3 ± 8.5 vs. Ctrl 61.7 ± 7.1), sex (10/6 vs. 7/4) and BMI (25.4 ± vs. 24.1). Mean duration of motor symptoms in the patient group was 5.5 ± 4.5 years, mean L-dopa equivalent dose 694 ± 340 mg/d. Objective measures for gastric emptying and subjective GI function did not differ between both groups OFF medication. Patients reported significantly more subjective orthostatic hypotension (OH) symptoms prior to testing (whilst on dopaminergic medication) than Ctrl subjects (8.9 ± 6.2 vs. 1.8 ± 3.0, p = 0.001), although Schellong measurements did not differ significantly in the absence of medication. Patients had a significantly higher HR (70.1 ± 11.7 vs. 60.5 ± 8.5, p = 0.02) than controls. Conclusion In the absence of medication interfering with GI function and cardiovascular control we did not see OH or delayed gastric emptying in early-motor PD patients. The significantly higher subjective OH symptom-score whilst on dopaminergic medication might reflect its known influence on bp regulation. Ongoing HR variability analysis might clarify in how far a parasympathetic deficit might explain the HR difference.