Neural Oscillatory Dynamics of Auditory-Motor Integration Deficit During Speech Articulatory Control in Post-Stroke Aphasia.

Fluent speech relies on sensorimotor integration for the detection and correction of auditory feedback errors via articulatory gesture adjustments. Individuals with post-stroke aphasia exhibit deficits in processing and compensating for errors in their own speech feedback, yet the neural bases of such impairments remain poorly understood. This study used a formant-shifting auditory feedback alteration paradigm to examine the neural oscillatory dynamics of speech articulatory responses in post-stroke aphasia, with a focus on the contribution of frequency-specific activity patterns underlying error monitoring and compensatory behavior. Thirty-one participants with post-stroke aphasia and 34 neurologically intact controls produced a monosyllabic word under randomly presented normal and first-formant-shifted feedback conditions while EEG signals were recorded. Global field power analyses were performed across theta, alpha, low-beta, high-beta, and gamma bands, and linear mixed-effects models assessed group differences across temporal intervals before and after speech. The aphasia group showed reduced theta and alpha desynchronization, weaker low-beta suppression, and markedly elevated high-beta synchronization, particularly during pre-speech and late-production periods. Gamma activity increased from pre-speech to early-production in both groups, but aphasia exhibited a more sustained, effort-related gamma profile rather than the late-phase increase seen in controls. These results indicate widespread and temporally specific neural pathologies in aphasia, including reduced low-frequency desynchronization and exaggerated high-frequency synchronization. These patterns suggest weakened predictive coding and attentional engagement at a global neural scale, coupled with compensatory reliance on local processing. These frequency-specific signatures offer promising biomarkers to guide targeted, neuromodulation-informed rehabilitation strategies for post-stroke aphasia.