Autonomic dysfunction in subjects at high risk for Parkinson’s disease

Aim of this project was to evaluate autonomic dysfunction in subjects proposed to be at high risk to develop Parkinson’s disease (PD) compared to control subjects and PD patients at different disease stages. Combinations of substantia nigra hyperechogenicity (SN+) assessed by transcranial ultrasound (TCS), hyposmia, lifetime prevalence of depression and mild PD-specific motor signs were used to identify subjects at high risk for motor Parkinson’s disease (HR-PD). Supine and standing blood pressure (BP), hearth rate (HR), orthostatic, urinary, sexual and bowel symptoms were evaluated in HR-PD, healthy control subjects and PD patients, divided into mild and advanced stages. The study group consisted of 113 PD patients (mild PD n = 71, advanced PD, n = 42), 40 HR-PD individuals and 50 controls. Compared to controls, HR-PD subjects complained more often about urinary (p = 0.002) and bowel dysfunction (p = 0.001) and had a higher diastolic BP drop after standing (p = 0.01). The cumulative number of autonomic symptoms differentiated PD as well as HR-PD significantly from controls (p < 0.001). Advanced PD patients presented often and severe orthostatic symptoms, not significantly different from mild PD after concomitant medication correction. Our results support the presence of urinary and bowel dysfunction in subjects at high risk for motor PD. Presence and severity of orthostatic symptoms was higher during stages and increase in advanced stages, at least partly due to increase in dopaminergic and conflicting medication. Understanding the progression of non-motor aspects in PD might offer the possibility to use them as targets for disease-modifying therapies.