Pamela Trudeau-Fisette

Exploring consequences of short- and long-term deafness on speech production: A lip-tube perturbation study

Abstract Studies have reported strong links between speech production and perception. We aimed to evaluate the role of long- and short-term auditory feedback alteration on speech production. Eleven adults with normal hearing (controls) and 17 cochlear implant (CI) users (7 pre-lingually deaf and 10 post-lingually deaf adults) were recruited. Short-term auditory feedback deprivation was induced by turning off the CI or by providing masking noise. Acoustic and articulatory measures were obtained during the production of /u/, with and without a tube inserted between the lips (perturbation), and with and without auditory feedback. F1 values were significantly different between the implant OFF and ON conditions for the pre-lingually deaf participants. In the absence of auditory feedback, the pre-lingually deaf participants moved the tongue more forward. Thus, a lack of normal auditory experience of speech may affect the internal representation of a vowel.

Speaking Clearly for the Blind: Acoustic and Articulatory Correlates of Speaking Conditions in Sighted and Congenitally Blind Speakers

Compared to conversational speech, clear speech is produced with longer vowel duration, greater intensity, increased contrasts between vowel categories, and decreased dispersion within vowel categories. Those acoustic correlates are produced by larger movements of the orofacial articulators, including visible (lips) and invisible (tongue) articulators. Thus, clear speech provides the listener with audible and visual cues that are used to increase the overall intelligibility of speech produced by the speaker. It is unclear how those cues are produced by visually impaired speakers who never had access to vision. In this paper, we investigate the acoustic and articulatory correlates of vowels in clear versus conversational speech, and in sighted and congenitally blind speakers. Participants were recorded using electroarticulography while producing multiple repetitions of the ten Quebec French oral vowels in carrier sentences in both speaking conditions. Articulatory variables (lip, jaw, and tongue positions) as well as acoustic variables (contrasts between vowels, within-vowel dispersion, pitch, duration, and intensity) were measured. Lip movements were larger when going from conversational to clear speech in sighted speakers only. On the other hand, tongue movements were affected to a larger extent in blind speakers compared to their sighted peers. These findings confirm that vision plays an important role in the maintenance of speech intelligibility.

Effects of blindness on production–perception relationships: Compensation strategies for a lip-tube perturbation of the French [u]

ABSTRACT The impact of congenital visual deprivation on speech production in adults was examined in an ultrasound study of compensation strategies for lip-tube perturbation. Acoustic and articulatory analyses of the rounded vowel /u/ produced by 12 congenitally blind adult French speakers and 11 sighted adult French speakers were conducted under two conditions: normal and perturbed (with a 25-mm diameter tube inserted between the lips). Vowels were produced with auditory feedback and without auditory feedback (masked noise) to evaluate the extent to which both groups relied on this type of feedback to control speech movements. The acoustic analyses revealed that all participants mainly altered F2 and F0 and, to a lesser extent, F1 in the perturbed condition – only when auditory feedback was available. There were group differences in the articulatory strategies recruited to compensate; while all speakers moved their tongues more backward in the perturbed condition, blind speakers modified tongue-shape parameters to a greater extent than sighted speakers.

Compensations to auditory feedback perturbations in congenitally blind and sighted speakers: Acoustic and articulatory data

This study investigated the effects of visual deprivation on the relationship between speech perception and production by examining compensatory responses to real-time perturbations in auditory feedback. Specifically, acoustic and articulatory data were recorded while sighted and congenitally blind French speakers produced several repetitions of the vowel /ø/. At the acoustic level, blind speakers produced larger compensatory responses to altered vowels than their sighted peers. At the articulatory level, blind speakers also produced larger displacements of the upper lip, the tongue tip, and the tongue dorsum in compensatory responses. These findings suggest that blind speakers tolerate less discrepancy between actual and expected auditory feedback than sighted speakers. The study also suggests that sighted speakers have acquired more constrained somatosensory goals through the influence of visual cues perceived in face-to-face conversation, leading them to tolerate less discrepancy between expected and altered articulatory positions compared to blind speakers and thus resulting in smaller observed compensatory responses.

Auditory feedback perturbation of vowel production: A comparative study of congenitally blind speakers and sighted speakers

Studies with congenitally blind speakers show that visual deprivation yields increased auditory discrimination abilities as well as reduced amplitude of labial movements involved in vowel production, compared with sighted speakers. To further investigate the importance of auditory and visual feedback in speech, a study of auditory perturbation of rounded vowels was conducted in congenitally blind and sighted French speakers. Acoustic and articulatory (electromagnetic articulography) recordings from ten congenitally blind speakers and ten sighted speakers were obtained during the production of the French rounded vowel /o/. All participants were first asked to produce the vowel repeatedly in a normal condition, i.e., with regular auditory feedback. In the perturbed condition, participants received, in real-time through headsets, an altered version of their speech, in which F2 was gradually increased up to 500 Hz. To compensate for this perturbation, speakers had to enhance lip protrusion and/or tongue retraction. These adaptive maneuvers should have been concurrent with auditory perception abilities. Preliminary results show that congenitally blind speakers gave greater weight to auditory perception than their sighted peers, while compensating differently for the perturbations. These findings support the hypothesis that vision plays a significant role in the implementation of phonological targets.

Vowel production in sighted adults and blind adults: A study of speech adaptation strategies in high-intensity background noise

Recent studies have shown that congenitally blind speakers have greater auditory discrimination acuity than sighted speakers [Menard, Dupont, Baum, and Aubin, J. Acoust. Soc. Am. 126, 1404–1414 (2009)]. At the production level, however, blind speakers produce smaller displacements of the lips (visible articulator) than their sighted peers. In order to further investigate the impact of visual experience on the articulatory gestures used to produce intelligible speech, adaptation strategies in background noise was studied in blind and sighted speakers. Ten sighted and 10 congenitally blind adult French participants were recorded during the production of the vowels /i/, /y/, /u/, /a/ in a CVC context. Two conditions were elicited: with high-intensity noise heard through headphones and without noise. Synchronous acoustic and articulatory data were recorded using the Carstens AG500 Electromagnetic Articulograph system. Formant measures and movements of the lips and tongue were analyzed. Results reveal that bli...

Development of acoustic speech discrimination abilities in school-aged children

The acquisition of speech perception skills is challenging for children. Although some studies have shown that categorical perception boundaries become steeper during childhood and are sometimes shifted in children compared to adults, very few experiments on discrimination abilities in children have been conducted. To investigate this, we conducted a perceptual discrimination task in school-aged children. Sixty-seven 6- to 12-year-old native Quebec French-speaking children were asked to complete a speech perception task that used an AXB scheme. The children were asked to discriminate synthesized 5-formant vowels belonging to three continuums: /i-e/ and /e-o/ (in which stimuli were equally stepped along F1) and /e-o/ (in which stimuli were equally stepped along F2). There was a significant effect of age on peak discrimination scores, with older children having higher peak scores than younger children. There was no effect of age on the location of the categorical boundary on the three tested continuums. The...

Maintaining vowel distinctiveness in children with Steinert Myotonic Dystrophy: An ultrasound study

Speech production entails appropriately timed contractions of many muscles. Steinert myotonic dystrophy, a neurodegenerative disease that causes muscle weakness and difficulties in muscle relaxation after muscle contraction, frequently affects orofacial articulatory dynamics leading to decreased speech intelligibility. We aimed to investigate the articulatory and acoustic characteristics of cardinal vowels produced by children with Steinert disease. We recruited fourteen 6- to 14-year-old French-speaking children diagnosed with Steinert disease and 14 aged-matched typically developing children. They were asked to produce repetitions of the vowels /i a u/ in consonant-vowel (CV) contexts. A synchronized ultrasound, Optotrak motion tracking system, and audio recording system was used to track lip and jaw displacement as well as tongue shape and position. Duration and formant values were also extracted. The Euclidean distance between vowels, in the formant space, was reduced in children with Steinert disease...

Prosodic strengthening at the edges of prosodic domains in sighted and blind speakers

Recent studies have shown that when producing isolated vowels, congenitally blind speakers produce smaller displacements of the lips (visible articulators), compared with their sighted peers. To investigate the role of visual experience on articulatory gestures used to produce salient speech contrasts, the production of vowels at the edges of low-level prosodic domains and high-level prosodic domains (in which gestures are reported to be strengthened) was studied in adult speakers of Quebec French. Ten sighted and ten congenitally blind participants were recorded during the production of the vowels /i/, /y/, /u/, /a/ in initial and final positions of two prosodic domains: word and intonational phrase. Synchronous acoustic and articulatory data were recorded using the Carstens AG500 Electromagnetic Articulograph system. Formant measures as well as displacements of the lips and tongue were analyzed. The results revealed that speakers produced larger ranges of lip and tongue movements at the edges of higher ...

Sensorimotor development and speech production

According to Perkell’s view [J. Perkell, J. Neurol. 25, 382–407], phonemic goals correspond to multidimensional spaces in the auditory and somatosensory dimensions. The relationships between sensory goals and motor actions in speech are acquired during infancy through feedback-based control mechanisms. Although there have been numerous studies of speech development, little is known about the specific roles of auditory and somatosensory feedback. This paper reviews a few studies of how pre-school-aged children rely on sensory feedback to reach phonemic targets. The studies looked at children with normal-hearing and deaf children with cochlear implants. Vowels and consonants were recorded in various prosodic contexts (neutral and under contrastive emphasis) and perturbation conditions (with or without artificial perturbations of the articulators). Acoustic, articulatory, and perceptual analyses were conducted to assess the degree to which children reached the targets. The data showed that although children’...