OBJECTIVE: Sleep disturbances are common in patients with Alzheimer disease (AD) and can contribute to cognitive dysfunction and a negative impact on patients' and caregivers' quality of life. The purpose of this study was to evaluate whether subtypes of sleep disturbance could be identified in patients with AD and to assess the relation of these subtypes to patient characteristics and caregiver mood.

METHODS: As part of routine clinical assessment, primary caregivers of 344 patients with AD completed a questionnaire that included five items about the patients' sleep. Patients' cognitive and functional status and their mood were assessed as was caregivers' mood. Latent class analysis was used to define subgroups of patients based on their sleep patterns. After identification of groups of sleep disturbance, the relation of group membership to patient and caregiver characteristics was also evaluated.

RESULTS: Analyses revealed groups with moderate and severe sleep problems as well as a group without problems. Patients with more severe sleep disturbance were older, less well educated, and had poorer cognitive and functional status. Caregiver and patient depression was related to membership in the severe group, suggesting that both may contribute to caregivers' ratings of more severe sleep disturbance, whereas only patient depression was related to membership in the moderate group.

CONCLUSION: Sleep problems in patients with AD are related to poorer cognitive and functional status and patient and caregiver depression. Caregiver depression was most closely related to more severe patient sleep disturbance.