Investigation of Nocturnal Hypokinesia and Health-Related Quality of Life in Parkinsonian Patients with the Korean Version of the Nocturnal Hypokinesia Questionnaire.

To assess nocturnal hypokinesia using the Korean version of the Nocturnal Hypokinesia Questionnaire (NHQ-K) in Parkinson's disease (PD) patients across disease stages. We developed the NHQ-K and performed questionnaire-based interviews with 108 PD patients from three referral hospitals. Clinical associations of nocturnal hypokinesia and its impact on health-related quality of life (HRQoL) were also analyzed. The NHQ-K showed acceptable internal consistency (0.83) and interrater reliability (0.95). Nocturnal hypokinesia significantly affected HRQoL in PD patients at both the early and advanced stages (adjusted p < 0.001). Increased severity of nocturnal hypokinesia was associated with dyskinesias, off-period disability, apathy, and anxious mood in PD patients (adjusted p < 0.01) after controlling for disease severity and medication dose. The NHQ-K is useful for screening nocturnal hypokinesia in PD patients. Given the high impact of nocturnal hypokinesia on HRQoL, comprehensive management of nocturnal disability is needed for PD patients.