Narrative video scene description task discriminates between levels of cognitive impairment in Alzheimer’s disease.

The process of interpreting and acting upon the visual environment requires both intact cognitive and visual systems. The narrative description (ND) task, initially developed to detect changes in ecologically relevant visual function in people with impaired vision, is an objective measure of the ability to perceive, understand, and describe a visual scene in a movie clip. Objective: Because the ND task draws heavily on semantic and working memory ability in addition to basic visual perception, we aimed to assess the discriminative performance of this task across levels of cognitive impairment. Method: We recruited 56 participants with cognitive status ranging from normal cognition to mild dementia (median age 82, range 66 to 99 years) to watch 20 30-s video clips and describe the visual content without time constraints. These verbal responses were transcribed and processed to generate ND shared word scores using a “wisdom of the crowd,” natural-language processing approach. We compared ND scores across diagnostic groups, and used linear mixed models to examine decrements in task performance. Results: There was a stepwise decline of ND scores with increasing levels of cognitive impairment. Additional analyses showed that ND performance was highly related to performance on the Montreal Cognitive Assessment (MoCA) and domain-specific neuropsychological tests for semantic fluency and set shifting. Other models demonstrated differences in ND performance related video content between cognitively normal and impaired participants. Conclusion: The ND test was able to detect decrements in task performance between levels of cognitive impairment and was related to other global neuropsychological measures. (PsycInfo Database Record (c) 2020 APA, all rights reserved)Key Points: Question: This study asked if cognitive and linguistic deficits could be detected using a task of visual scene comprehension among individuals with cognitive impairment resulting from Alzheimer’s disease. Findings: Results suggest that individuals with high levels of cognitive impairment performed worse than those with milder forms of cognitive impairment and that the task is associated with other neuropsychological measures. Importance: These findings confirm a novel way to examine cognitive impairment through a global measure of cognition and linguistic ability. Next Steps: Future studies might apply this method to remote data collection/monitoring within a clinical trial or observational study for ease of use.