Skeletal Muscle Pump Impairment in Parkinson's Disease: Preliminary Results

The purpose of this study is to investigate if impairments in leg muscle contractions affect blood pressure (BP) regulation in patients with Parkinson's disease (PD). Simultaneous BP, electrocardiogram, and bilateral electromyogram (EMG) of the tibialis anterior, lateral and medial gastrocnemius, and soleus muscles were recorded from 16 patients with PD and 12 healthy controls in supine (5 minutes), head-up tilt test (15 minutes), and standing positions (5 minutes). Convergent Cross Mapping was used to examine the causal relationship of the muscle pump baroreflex $(SBP\rightarrow EMG_{imp})$ and the effect of muscle activity on systolic blood pressure $(EMG_{imp}\rightarrow SBP)$. Preliminary results showed that PD participants have less effective lower leg skeletal muscle pump compared to the control group while no difference was found in the muscle pump baroreflex. Muscle pump causality was lower for all muscles in PD patients compared to the control group. Our data suggest that PD patients show a reduced causal effect of skeletal muscle pump on blood pressure. The obtained results also highlight the impairment of the ability of muscle pump to effectively control blood pressure in PD patients. The findings of this study can assist in the development of an effective system for monitoring orthostatic tolerance via muscle pump to prevent syncope and falls in PD.