Prevalence of non-motor symptoms in young-onset versus late-onset Parkinson's disease.

Non-motor symptoms (NMS) of Parkinson's disease (PD) have only recently been increasingly recognized for their impact on a patient's quality of life. In this study, we applied the validated, comprehensive self-completed NMS questionnaire for PD (NMS Quest) to 101 patients with young-onset PD (onset between 21 and 45 years, YOPD) and 107 patients with late-onset PD (onset of PD ≥ 55 years, LOPD). The mean total NMS (NMSQ-T) was 11.9 ± 6.0 (range: 0 to of a maximum of 26) in LOPD and 7.7 ± 5.8 (range: 0 to of a maximum of 26) in YOPD (p < 0.05). Compared to YOPD, dribbling of saliva, loss of taste/smell, nocturia, forgetfulness, loss of interest, hallucinations, lack of concentration, anxiety, change in libido and difficulty in sexual activities, were significantly more prevalent in LOPD. The only NMS more prevalent in YOPD were restless legs and sweating, although such findings might be associated with drug effects. Among the nine NMS Quest domains, in both LOPD and YOPD patients the three most prevalent domains were depression/anxiety, urinary and sexual. Also, in both groups, hallucinations/delusions had the lowest frequency. In the multivariate linear regression model, the Hoehn and Yahr (HY) stage of the disease and activities of daily living scores in YOPD patients, while only the HY stage in LOPD patients appeared to be statistically significant predictors of increasing number of NMS. In contrast to a previous suggestion that YOPD patients might have an increased risk for NMS, we found a higher prevalence of NMS in LOPD patients than in those with YOPD.