Play It Again: Differential pupillometry responses to familiar and unfamiliar music: Findings from typical and atypical Alzheimer’s disease

Abstract

AbstractBackgroundMusic has gained more attention than other art forms as a potent tool in supporting cognitive, emotional and social functioning in dementia populations. Methods for measuring moment‐to‐moment responses ‐ rather than comparing pre‐ and post‐stimulus effects ‐ may enable tailoring of musical experiences for the individual. The current study investigated whether differential pupillometry responses could be established for familiar/unfamiliar music in people living with early‐mid stages of typical, memory‐led Alzheimer’s disease (tAD), atypical ‘visual variant’ of Alzheimer’s disease (posterior cortical atrophy; PCA), and healthy age‐matched controls.MethodPatient groups [tAD = 18; PCA = 21] were recruited via the Specialist Cognitive Disorders clinic at the National Hospital for Neurology and Neurosurgery, London, UK. Healthy older adults [N = 90] were recruited opportunistically via departmental research databases/Join Dementia Research.Pupillometry responses were recorded while participants listened to 30 musical excerpts [classical (N = 5); 1960s (N = 10), 1970s (N = 10), reversed ‘de novo’ tracks (N = 5)], each rated for familiarity: (a) a priori (known/unknown); (b) self‐rated by participants (not familiar‐extremely familiar); and (c) whether the excerpt evoked a memory (yes/no). Background, basic clinical and music experience information was collected, alongside additional neuropsychological assessment in the patient groups.Separate linear regression models obtaining cluster robust standard errors were run to predict pupil response from a priori predicted‐ and subjective‐ratings of music familiarity in each participant group, controlling for demographic factors including disease severity.ResultResults indicate significant within‐group effects of familiarity on pupil response in controls and the tAD group. No effects were observed within the PCA group. Preliminary between‐group analyses including diagnosis as a predictor revealed that, for each music‐pupillometry model, tAD overall pupil dilation responses did not differ significantly compared to controls, however a significant difference was observed between PCA and control pupil dilation responses.ConclusionThe results are discussed in relation to the preliminary finding of preserved differential pupillometry responses to familiar/unfamiliar music in the tAD group. Although the PCA results question the utility of pupillometry in individuals with significant oculomotor dysfunction, pupillometry may serve as a useful non‐invasive ‘biosignal’ for establishing in‐the‐moment response to music, including in post‐verbal individuals in the later stages of dementia.