Relationship of Subjective and Objective Sleep Quality with Caregiver Burden in Patients with Alzheimer’s Disease

Background and Objective Sleep disturbance in patients with Alzheimer’s disease (AD) could increase institutionalization due to caregiver burden. The objective of this study was to examine the relationship of subjective and objective sleep quality with caregiver burden in AD patients with insomnia symptoms. Methods AD patients of mild to moderate degree were recruited. They were assessed with the Pittsburgh Sleep Quality Index (PSQI), Korean version of the Epworth Sleepiness Scale, and Mini-Mental Status Examination in the Korean version of Consortium to Establish a Registry for Alzheimer’s Disease Assessment Packet. Caregiver burden was evaluated with Korean version of the Neuropsychiatric Inventory Questionnaire (KNPI-Q) and Korean version of the Zarit Burden Interview (ZBI-K). Actigraphy recording (Actiwatch 2; Philips Respironics) was conducted for five days at home. Thirty-four patients (age 78.44 ± 6.14, M:F = 9:25) were analyzed. These patients were divided into two groups by the median of KNPI-Q for caregiver distress [KNPI-Q(d)] and ZBI-K scores. Sleep parameters were compared between the two groups. Results Among seven components of PSQI, sleep latency was correlated with KNPI-Q(d) score. The patients with higher KNPI-Q(d) scores had lower sleep efficiency (SE) (p = 0.002), greater wake after sleep onset (p = 0.037), and higher fragmentation index (p = 0.040) than those with lower KNPI-Q(d) scores. Those with higher ZBI-K scores had lower SE (p = 0.026) than those with lower ZBI-K scores. Stepwise multiple regression revealed that SE predicted 16% of KNPI-Q(d) scores (p = 0.012). Conclusions Difficulty in sleep initiation according to subjective reports was associated with caregiver burden in our AD patients. In objective sleep quality, a significant difference in difficulty of sleep maintenance was found between higher and lower caregiver burden groups. This suggests that sleep maintenance is essential for reducing caregiver burden.