Keep calm and listen : subjective cognitive decline modulates cortical tracking of speech and music in different expressive styles

Abstract

Subjective cognitive decline (SCD) approximately doubles the risk of developing MCI and dementia in older adults. While existing studies focus primarily on memory deficits, we investigated how SCD modulates speech and music perception to disentangle the roles of sensory and cognitive processing at this early stage. EEG was collected from 56 Cantonese-speaking, cognitively normal older adults (aged 60–70) while they listened to speech and music across four expressive styles varying in valence, arousal, and dominance. Cortical tracking strength (CTS) was estimated by fitting encoding models between acoustic features and EEG signals filtered in delta and theta bands. We found that CTS decreased with increasing SCD severity, but this effect was specific to scrambled speech (theta band) and calm music (delta and theta bands). These findings suggest that SCD-related deficits would arise for both speech (if bottom-up acoustic cues are relied upon heavily) and music perception (if top-down sustained attention is required for tracking endogenous rhythms). By incorporating different expressive styles, our results reveal that SCD involves decline in both sensory and cognitive processing in a domain-specific manner.