Impairments and Variability in Auditory–Motor Synchronization in Individuals With Aphasia and With Advancing Age

Purpose: Auditory–motor synchronization, the ability to align motor output with external auditory input, reflects neural coupling between auditory and motor cortices and supports tracking of the speech envelope and linguistic cues, essential for speech perception and production. In aphasia, disrupted neural coupling may impair synchronization and affect speech and language processing. While domain-general synchronization (i.e., tapping to metronome or musical stimuli) has been studied previously, its relationship to speech-specific synchronization (i.e., speech-to-speech) remains underexplored, particularly in the context of aphasia-related impairments. This study examined the feasibility of assessing auditory–motor synchronization in individuals with aphasia and with advancing age, particularly focusing on individual variability. Method: Sixteen individuals with aphasia and 32 age-matched neurotypical controls completed both tapping and speech-to-speech synchronization tasks. Synchronization abilities and their relations to auditory, musical, and linguistic prosodic abilities were analyzed using linked models. Results: Despite the speech-specific demands for individuals with aphasia, adaptations to data preprocessing and cleaning retained feasibility of the speech-sync task in our sample. Individuals with aphasia showed reduced synchronization abilities across both domain-general and speech-specific synchronization compared to neurotypical controls. In both groups, better auditory, musical, and linguistic prosodic abilities were associated with enhanced speech-specific synchronization. Conclusions: These findings highlight the relevance of auditory–motor synchronization for impaired and unimpaired speech and language processing. Results underscore the importance of accounting for individual variability, considering both challenges and resources in synchronization abilities, potentially informing individualized therapeutic interventions in aphasia rehabilitation. Supplemental Material: https://doi.org/10.23641/asha.34914330