Developing and describing a typology of lucid episodes among people with Alzheimer's disease and related dementias

INTRODUCTION: This study examined lucid episodes among people living with late-stage Alzheimer's disease and related dementias (PLWD) and then developed a typology of these episodes to help characterize them. METHODS: Family caregivers of PLWD provided information about witnessed episodes, including proximity to death, cognitive status, duration, communication quality, and circumstances prior to lucid episodes on up to two episodes (caregiver N = 151; episode N = 279). Latent class analysis was used to classify and characterize empirically distinct clusters of lucid episodes. RESULTS: Four lucid episode types were identified. The most common type occurred during visits with family and among PLWD who lived > 6 months after the episode. The least common type coincided with family visits and occurred within 7 days of the PLWD's death. DISCUSSION: Findings suggest that multiple types of lucid episodes exist; not all signal impending death; and some, but not all, are precipitated by external stimuli.