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Question: Audiotactile cues can enhance speech perception in noise, yet the neural mechanisms underlying vibrotactile speech processing remain poorly understood, particularly in individuals with single-sided deafness (SSD). The present study investigated how adults with acquired SSD process vibrotactile speech-like stimuli compared to simple vibrotactile frequencies, and how these responses differ from normal-hearing (NH) controls.

Methods: Twenty adults with acquired SSD and 20 age- and sex-matched NH controls underwent functional magnetic resonance imaging (fMRI) during vibrotactile stimulation using simple frequencies (125 Hz) and vibrotactile speech-like (VS) paradigms applied to the right index finger. Behavioral performance (hit rates, reaction time) was measured. Region-of-interest analyses quantified activation in primary auditory cortex (PAC) and primary somatosensory cortex (S1). Additional analyses assessed differences in left vs. right SSD and correlations between neural measures and clinical variables.

Results: Both groups responded faster to 125 Hz than VS stimuli (p = 0.03). Participants with SSD showed widespread recruitment during vibrotactile speech stimulation, including middle temporal gyrus, superior frontal gyrus and frontal operculum. Regional analyses revealed reduced stimulus selectivity in S1 in SSD compared to NH. Furthermore, robust left-hemisphere dominance was found in PAC for both left and right SSD during both stimuli conditions. Strong associations were present between left superior frontal gyrus activation and clinical factors, including age (r = 0.54, p = 0.01), sound localization (r = –0.57, p = 0.03), and measures of executive memory (r = –0.45, p = 0.04).

Conclusion: Vibrotactile speech-like stimuli strongly engage reorganized auditory networks, highlighting their potential relevance for understanding sensory compensation and informing cochlear-implant prognostics.