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

OBJECTIVE To assess nocturnal hypokinesia using the Korean version of the Nocturnal Hypokinesia Questionnaire (NHQ-K) in Parkinson's disease (PD) patients across disease stages. METHODS 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. RESULTS 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. CONCLUSION 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.