An observational study protocol to capture, validate and characterise lucid episodes in people living with advanced dementia receiving hospice care.

Introduction: Lucid episodes (LEs) in advanced neurodegenerative disease, characterised by a transient recovery of abilities, have been reported across neurological conditions, including Alzheimer's disease and related dementias. Evidence on LEs in dementia is extremely limited and draws predominantly from retrospective case reports. Lucidity in dementia has received growing attention given the clinical, caregiving and potential epidemiological implications of even a temporary return of abilities in advanced disease. Following a funding initiative by the National Institute on Aging, several new investigations are focused on establishing foundational evidence on lucidity in dementia. The objectives of this study are to capture, characterise and validate potential LEs via audiovisual observation, computational linguistic and timed-event coding of audiovisual data, and informant case review for face validation of LEs.

Methods And Analysis: This prospective multifaceted observational study will investigate LEs in advanced dementia through longitudinal audiovisual observation within an inpatient hospice unit. Audiovisual data will be coded to generate variables of participant verbal output, verbal expressions, non-verbal communicative actions and functional behaviours to enable measurement of features that can be used to characterise LEs. Multiple methods will be used to identify potential LEs including field interviews with caregivers/clinicians who witness significant events during data collection, reports from research staff who witness significant events during data collection and detection by researchers during video data processing procedures. Potential LEs will undergo a structured case review with informants familiar with the participant to facilitate validation and enable triangulation across measures generated through coding.

Ethics And Dissemination: This study will be conducted in accordance with all Federal Policies for the Protection of Human Subjects and the protocol (ID 2021-1243) has been approved by the University of Wisconsin-Madison Institutional Review Board. Findings will be disseminated via scientific conferences, journal publications and newsletters shared with participants and through dementia-focused and caregiver-focused networks.