Correlation between the Effect of Orofacial Somatosensory Inputs in Speech Perception and Speech Production Performance

ABSTRACT

Orofacial somatosensory inputs modify the perception of speech sounds. Such auditory-somatosensory integration likely develops alongside speech production acquisition. We examined whether the somatosensory effect in speech perception varies depending on individual characteristics of speech production. The somatosensory effect in speech perception was assessed by changes in category boundary between /e/ and /ø/ in a vowel identification test resulting from somatosensory stimulation providing facial skin deformation in the rearward direction corresponding to articulatory movement for /e/ applied together with the auditory input. Speech production performance was quantified by the acoustic distances between the average first, second and third formants of /e/ and /ø/ utterances recorded in a separate test. The category boundary between /e/ and /ø/ was significantly shifted toward /ø/ due to the somatosensory stimulation which is consistent with previous research. The amplitude of the category boundary shift was significantly correlated with the acoustic distance between the mean second – and marginally third – formants of /e/ and /ø/ productions, with no correlation with the first formant distance. Greater acoustic distances can be related to larger contrasts between the articulatory targets of vowels in speech production. These results suggest that the somatosensory effect in speech perception can be linked to speech production performance.

KEYWORDS:

• Auditory-somatosensory integration
• production-perception link
• somatosensory feedback
• vowel categorization

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Sklowdoska-Curie Grant Agreement No 860755 (Comm4CHILD project) and by National Institute on Deafness and Other Communication Disorders Grant R01-DC017439.