Abstract
<title>Abstract</title> <p> <bold>Background and Objectives:</bold> Rhythmic sensory stimulation has emerged as a promising approach to improve gait after stroke. Using an EEG frequency-tagging paradigm, we previously demonstrated that healthy individuals exhibit robust neural entrainment at the natural walking cadence (2 Hz), particularly in response to auditory and audiovisual gait-related stimuli. Whether this neural synchronization is preserved after stroke remains unknown. We investigated neural entrainment to gait-related auditory, visual, and audiovisual stimuli presented at 2 Hz in individuals with chronic stroke. <bold>Methods</bold> : Twenty individuals with chronic unilateral stroke and 21 age- and sex-matched healthy controls completed auditory, visual, and audiovisual tasks in which rhythmic (2 Hz) and temporally random gait-related stimuli were presented while high-density EEG was recorded. Stimulus-locked neural responses at 2 Hz were quantified using frequency-domain analyses across sensorimotor, temporal, and occipital regions of interest. Linear mixed-effects models examined the effects of group, condition, and brain region. Participants also completed questionnaires assessing agency, ownership, and movement fluidity. <bold>Results</bold> : Stroke participants exhibited significantly reduced 2-Hz neural entrainment compared with controls, with a significant Group effect (p = 0.014) and a Condition × Region × Group interaction (p = 0.028). Deficits were most pronounced within sensorimotor regions during auditory (p = 0.017) and audiovisual (p = 0.043) stimulation, and within occipital regions during audiovisual stimulation (p = 0.010). No group differences were observed for visual stimulation in sensorimotor regions or for auditory stimulation in occipital regions. Despite preserved sensitivity to rhythmic compared with random sequences, stroke participants reported reduced agency and movement fluidity during the exposure of visual and audiovisual stimuli. <bold>Discussion</bold> : Chronic stroke is associated with modality-specific deficits in neural entrainment to gait-related rhythmic stimulation at the natural walking cadence (2 Hz), with the greatest impairment observed during auditory and audiovisual processing in sensorimotor and occipital networks. These results identify disrupted multisensory neural synchronization as a potential mechanism underlying gait impairment after stroke and support EEG frequency-tagging as a promising biomarker for characterizing network dysfunction and guiding the development of individualized rhythm-based audiovisual rehabilitation strategies. </p>