Changes in Speech Production Following Perceptual Training With Orofacial Somatosensory Inputs.

PURPOSE: Orofacial somatosensory inputs play an important role in speech motor control and speech learning. Since receiving specific auditory-somatosensory inputs during speech perceptual training alters speech perception, similar perceptual training could also alter speech production. We examined whether the production performance was changed by perceptual training with orofacial somatosensory inputs. METHOD: We focused on the French vowels /e/ and /ø/, contrasted in their articulation by horizontal gestures. Perceptual training consisted of a vowel identification task contrasting /e/ and /ø/. Along with training, for the first group of participants, somatosensory stimulation was applied as facial skin stretch in backward direction. We recorded the target vowels uttered by the participants before and after the perceptual training and compared their F1, F2, and F3 formants. We also tested a control group with no somatosensory stimulation and another somatosensory group with a different vowel continuum (/e/-/i/) for perceptual training. RESULTS: Perceptual training with somatosensory stimulation induced changes in F2 and F3 in the produced vowel sounds. F2 decreased consistently in the two somatosensory groups. F3 increased following the /e/-/ø/ training and decreased following the /e/-/i/ training. F2 change was significantly correlated with the perceptual shift between the first and second half of the training phase in the somatosensory group with the /e/-/ø/ training, but not with the /e/-/i/ training. The control group displayed no effect on F2 and F3, and just a tendency of F1 increase. CONCLUSION: The results suggest that somatosensory inputs associated to speech sound inputs can play a role in speech training and learning in both production and perception.

Correlation between the effect of orofacial somatosensory inputs in speech perception and speech production performance.

Introduction: 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. Methods: 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. Results: The category boundary between /e/ and /ø/ was significantly shifted towards /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. Discussion: 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.

Auditory outcome following aneurysmal subarachnoid haemorrhage.

Auditory deficits are increasingly recognised following aneurysmal subarachnoid haemorrhage (aSAH) and are thought to be of central rather than peripheral origin. Central hearing impairment, also known as auditory processing disorder (APD), often coexists with cognitive deficits and it is thought that APD has both auditory and cognitive elements. The aim of this study was to assess auditory outcome following aSAH and its relationship with cognition. A retrospective case-controlled study design was employed with aSAH cases and matched controls identified from the UK Biobank. Auditory and cognitive outcomes were assessed using the digit triplet test (DTT) and a test of psychomotor reaction time, respectively. Best DTT score was compared between cases and controls using the t-test. A regression-based mediation analysis was performed to assess whether cognition mediated auditory outcome. 270 aSAH patients with auditory outcomes were identified with an average follow-up of 106 months. A matched control cohort of 1080 individuals was also identified. The aSAH cohort had significantly impaired best DTT scores compared to matched controls (p = 0.002). Cognition significantly mediated auditory outcome following aSAH, accounting for 9.8% of the hearing impairment after aSAH. In conclusion significant hearing impairment follows aSAH. The deficit is bilateral and non-progressive. There is a link with cognitive deficit, pointing to a central rather than peripheral source, in keeping with an auditory processing disorder. All aSAH patients should be asked about hearing difficulty at follow-up and when present it should be investigated with peripheral and central auditory assessments, as well as cognitive tests.