Sleepwalking in Parkinson's disease: a questionnaire-based survey

Sleepwalking (SW) corresponds to a complex sleep-associated behavior that includes locomotion, mental confusion, and amnesia. SW is present in about 10% of children and 2-3% of adults. In a retrospective series of 165 patients with Parkinson's disease (PD), we found adult-onset ("de novo") SW "de novo" in six (4%) of them. The aim of this study was to assess prospectively and systematically the frequency and characteristics of SW in PD patients. A questionnaire including items on sleep quality, sleep disorders, and specifically also SW and REM sleep behavior disorder (RBD), PD characteristics and severity, was sent to the members of the national PD patients organization in Switzerland. In the study, 36/417 patients (9%) reported SW, of which 22 (5%) had adult-onset SW. Patients with SW had significantly longer disease duration (p = 0.035), they reported more often hallucinations (p = 0.004) and nightmares (p = 0.003), and they had higher scores, suggestive for RBD in a validated questionnaire (p = 0.001). Patients with SW were also sleepier (trend to a higher Epworth Sleepiness Scale score, p = 0.055). Our data suggest that SW in PD patients is (1) more common than in the general population, and (2) is associated with RBD, nightmares, and hallucinations. Further studies including polysomnographic recordings are needed to confirm the results of this questionnaire-based analysis, to understand the relationship between SW and other nighttime wandering behaviors in PD, and to clarify the underlying mechanisms.