Objectives: Individuals with hearing impairment can perceive speech sounds with the help of cochlear implants or hearing aids. Recent studies have shown that orofacial somatosensory inputs may modify speech perception. This study explored the potential role of such somatosensory inputs in speech perception in individuals with hearing impairment. Design: Twenty-one native French-speaking participants with various profiles of bilateral hearing impairment and wearing hearing aids and/or cochlear implants were tested to explore the extent to which an orofacial somatosensory stimulation, consisting in facial skin stretch provided by a robotic device, would affect their speech perception performance in a vowel identification task, in comparison with 25 participants with normal hearing. This potential somatosensory effect was evaluated in relation to their hearing ability assessed by both their hearing threshold of digits in acoustic noise and their audiological profile, and with their production ability assessed by variability in a vowel production task. Results: The somatosensory effects varied depending on participants' hearing ability, with three different profiles. A first group of eight participants, who were able to identify the vowels auditorily though with thresholds in noise higher than for individuals with normal hearing, did not show any somatosensory effect, with identical vowel identification scores without and with facial deformation. The other 13 participants were unable to auditorily identify the vowels and had high thresholds in noise. Among them, eight participants who had used a hearing device for a long duration (≥ 18 years) showed a strong somatosensory bias modifying vowel identification when facial deformation was present. These participants also showed greater variability in vowel production. The last five participants in this second group showed no somatosensory effect at all. Conclusion: These three profiles were related to the role of auditory experience and hearing ability in the development of auditory-somatosensory integration.
Ashokumar et al. (2026) studied this question.