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.

Associations between recall of proper names in story recall and CSF amyloid and tau in adults without cognitive impairment

Neuropsychological measures sensitive to decline in the preclinical phase of Alzheimer's disease are needed. We previously demonstrated that higher amyloid-beta (Aβ) assessed by positron emission tomography in adults without cognitive impairment was associated with recall of fewer proper names in Logical Memory story recall. The current study investigated the association between proper names and cerebrospinal fluid biomarkers (Aβ42/40, phosphorylated tau181 [pTau181], neurofilament light) in 223 participants from the Wisconsin Registry for Alzheimer's Prevention. We assessed associations between biomarkers and delayed Logical Memory total score and proper names using binary logistic regressions. Sensitivity analyses used multinomial logistic regression and stratified biomarker groups. Lower Logical Memory total score and proper names scores from the most recent visit were associated with biomarker positivity. Relatedly, there was a 27% decreased risk of being classified Aβ42/40+/pTau181+ for each additional proper name recalled. A linear mixed effects model found that longitudinal change in proper names recall was predicted by biomarker status. These results demonstrate a novel relationship between proper names and Alzheimer's disease-cerebrospinal fluid pathology.