Longitudinal assessment of autonomic dysfunction in early Parkinson's disease

Introduction: Clinical correlates of autonomic nervous system (ANS) dysfunction in early Parkinson's disease (PD) have been addressed mainly in a cross-sectional way. Methods: This is a combined cross-sectional and longitudinal prospective study of ANS dysfunction using the SCOPA-AUT in PD patients at the Hoehn and Yahr stage 1 with disease duration < 2 years. PD patients (n = 107) were compared to healthy controls (HC, n = 79), and then followed-up for over 3 years. The severity of PD, depression, anxiety, apathy and cognitive impairment were evaluated using rating scales. Results: At least one symptom of ANS dysfunction was present in 71% of PD patients in comparison to 30.4% of HC, and in all PD patients after three years. The overall severity of dysautonomia symptoms was mild (SCOPA-AUT mean +/- SD; 4.16 +/- 5.0), but worsened by 23%, 86% and 0.3% during the 1st, 2nd and 3rd year respectively. Nighttime voiding (38.3%), constipation (30.8%) and straining for defecation (29%) were the most common symptoms. Prevalence and severity of urinary, gastrointestinal, and orthostatic symptoms increased, in contrast to thermoregulatory and pupillomotor symptoms. Frequency of symptoms suggestive of multi-domain ANS dysfunction rose from 49% to 79%. Psychiatric symptoms and age, but not motor impairment, were associated with dysautonomia symptoms. Conclusion: Symptoms of ANS dysfunction were frequent in the initial motor stage of PD and progressed, yet remaining mild, within 3 years. An independent progression of dysautonomia symptoms from motor disability and its associations with non-motor, mainly psychiatric symptoms and age support the non-motor clustering in PD.