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Biomedical subjects

S G Fletcher

Publications and source records attributed to S G Fletcher.

At least 19 recordsLinked to original sources
PubMed1994

Comparing abilities of children with profound hearing impairments to learn consonants using electropalatography or traditional aural-oral techniques.

Two groups of nine children with profound hearing impairments and low intelligibility were taught to produce the consonants /t,d,k,g,s,z,S/ using either electropalatographic (palatometry) or traditional aural-oral techniques. Testing was completed pre-, immediately post-, and 6 months post-treatment by examining productions of CV syllables (V = /i,a/) using electropalatography-determined linguapalatal contacts and listener identifications. Intelligibility was also measured using the CID Picture Speech Intelligibility Evaluation (SPINE) test. Both groups improved their consonant productions as a result of 26 50-minute sessions. Sessions were given twice daily over 3- to 4-week training periods. Immediately post-treatment, the electropalatography-trained subjects produced better consonants as measured by linguapalatal contact patterns and listener identifications. The linguapalatal-contact patterns learned by the electropalatography-trained group better matched normal speaker productions than did those of the traditionally trained group. Both groups showed equal improvement for both post-treatment conditions when tested with the CID SPINE test. Although further research is needed, the results of this study suggest that electropalatographic techniques are, at least, equal alternatives to traditional aural-oral speech training techniques for speakers with profound hearing impairments.

Acoustic Stimulation↗
PubMed1992

Esophageal speaker articulation of /s,z/: a dynamic palatometric assessment.

Esophageal talker linguapalatal contact patterns and durations during /s/ and /z/ productions were examined using dynamic palatometry instrumentation. It was found that sibilant groove narrowing is a physiologic compensation for a reduced air supply in esophageal speech. The place of esophageal /s, z/ articulation was on the anterior portion of the alveolar ridge as seen in normal speakers. Average medial groove width for esophageal /s/ was narrower than the 5-7-mm groove characteristic of normal speakers. Groove widths averaged 3 mm for /s/ and 4 mm for /z/. Systematic changes in groove widths across speech sounds, syllable position, and vowel context were also observed. Use of a narrower lingual groove was interpreted as a significant articulatory maneuver to meter out a limited intraoral air supply and effect more normal fricative durations.

Articulation Disorders↗
PubMed1991

Teaching consonants to profoundly hearing-impaired speakers using palatometry.

Five profoundly hearing-impaired children were taught the consonants /t,d,k,g,s,z integral of/ using palatometry. Changes in linguapalatal contact patterns and listener perceptions showed significant improvement in the place and manner of consonants produced by all subjects. Velar stops were as easily and accurately learned as alveolar stops. Distinctive sibilants were also found by the end of training. Sounds not previously present in a subject's phonetic repetoire were learned more accurately than those present but inaccurate prior to therapy. Voicing errors persisted. Two of the subjects showed evidence of newly established, unsolicited coarticulated movements. The results indicated that visual articulatory modeling and feedback of linguapalatal contact patterns is an effective means of teaching consonants and improving speech intelligibility.

Adolescent↗
PubMed1991

Teaching vowels to profoundly hearing-impaired speakers using glossometry.

Glossometry was used to teach the four point vowels (/i,ae,u,a/) to 6 profoundly hearing-impaired children. Prior to treatment, all subjects evidenced centralized tongue positions during vowel productions. After 15 to 20 fifty-minute training sessions over 3- to 4-week time periods, all subjects showed greater diversification of tongue postures for the vowels, especially in tongue height. Listener identifications were generally better after therapy. The training results suggested that visually presented models and feedback of tongue positions can facilitate more appropriate tongue postures and improve vowel intelligibility by hearing-impaired speakers.

Adolescent↗
PubMed1991

[s] and [sh] as a function of linguapalatal contact place and sibilant groove width.

Sibilant groove place and width were initially examined during [s] [s] in isolation and in CV and VC syllables. The [s] was found to be produced through a 6- to 8-mm-wide groove near the front of the alveolar ridge by one talker and near the back of the ridge by the other. [s] was produced through a 10- to 12-mm groove behind the posterior border of the alveolar ridge by both. In the second experiment three subjects used visual articulatory feedback to vary sibilant groove width and place systematically. One subject was able to do this with comparatively few retrials; one had difficulty with certain targeted grooves; one had difficulty with many targeted grooves. The noises generated were replayed to 14 listeners who labeled them as "s," "probably s," "probably sh," or "sh." They usually heard the sound as [s] when the grooves were narrow and near the front of the alveolar process, [s] when the groove was wider and behind the alveolar process. Noise through grooves that matched natural speech places and widths usually produced higher listener recognition scores. Exceptions were found when the subjects had unusual difficulty in achieving stipulated groove widths and places.

Adult↗
PubMed1989

Palatometric specification of stop, affricate, and sibilant sounds.

This investigation used palatometry to study stops, sibilants, and affricates in CV syllables (C = t,d,k,g,tf,d3; V = i,a) spoken by nine normal 6- to 14-year-old children. The measures focused on place, manner, timing, and area of linguapalatal contact. Similarities and differences between the sound classes, actions across segments of the articulatory gestures, and age effects were identified and described. The affricates were observed to have stop and sibilant portions demarcated by a partial plateau in the linguapalatal contact releasing gesture. The sibilant portion was formed in the same place and with the same groove dimensions as /f,3/. The older subjects reached initial articulatory positions faster, produced the consonant sounds more quickly, generated vowels with shorter durations, and articulated more posteriorly than did younger ones.

Adolescent↗
PubMed1988

Speech production following partial glossectomy.

Changes in the dimensions and patterns of articulation used by three speakers to compensate for different amounts of tongue tissue excised during partial glossectomy were investigated. Place of articulation was shifted to parts of the vocal tract congruent with the speakers' surgically altered lingual morphology. Certain metrical properties of the articulatory gestures, such as width of the sibilant groove, were maintained. Intelligibility data indicated that perceptually acceptable substitute sounds could be produced by such transposed gestures.

Adult↗
PubMed1988

Compensating for a bite block in /s/ and /t/ production: palatographic, acoustic, and perceptual data.

Electropalatography was used to monitor linguapalatal contact patterns in /s/ and /t/. Talkers often compensated incompletely for a bite block, both immediately after its insertion (sample B1) and after 10 min of practice (sample B2). Significant differences in the number of sensors contacted were noted between normal and bite-block samples for both /s/ and /t/. Differences in length of constriction in /t/, and the A-P location and width of the groove in /s/ were also noted. The two native English subjects compensated better than three Arabic subjects, perhaps because English /s/ and /t/ are formed more posteriorily and with a smaller contact area than their Arabic counterparts. A significant correlation existed between the area and A-P location of linguapalatal contact. All five subjects formed a groove for /s/ in sample B2, but two often did not produce /t/ with complete constriction. This suggests a groove is critical for /s/, but complete constriction is not critical for /t/. The contact patterns in sample B2 more closely resembled normal speech than those in sample B1 in some instances, while in other instances the reverse was true. The conclusion that subjects sometimes overcompensated in sample B2 was supported by the results of detailed acoustic and perceptual analyses for one subject. Taken together, the results suggest that compensation for a bite block is not instantaneous, and that specific parameter values may be encoded in central phonetic representations.

Adult↗
PubMed1986

Visual feedback and lip-positioning skills of children with and without impaired hearing.

Interplay between visual feedback and lip-positioning skill was studied in 10 5- to 14-year-old children with normal hearing and 10 with severe to profound hearing impairment. With visual feedback, the subjects in both groups had similar response times and accuracy in matching six visually specified lip separation "targets." Special skill in processing visual information by the hearing-impaired subjects was suggested by higher velocities of lip movement toward the targets and shorter latencies in reaching the goal positions. In the responses of the hearing children, lip-closing movements were executed more accurately than opening movements both with and without visual feedback. In general, the findings showed that, given visually displayed lip-position targets and feedback from positioning actions, children can achieve the targets with high accuracy regardless of hearing status or prior speaking experience.

Adolescent↗
PubMed1985

Speech production and oral motor skill in an adult with an unrepaired palatal cleft.

The aim of this study was to identify maneuvers and strategies that enabled an adult speaker to produce "pressure" consonants intelligibly despite an open cleft of the palate. Dynamic palatometry indicated that this was achieved in part by increasing linguapalatal contact in stop sound production and narrowing the linguapalatal groove in sibilant sound production. These adaptations apparently enabled the talker to compensate for reduced air supply in a manner similar to that identified previously in responses of subjects with esophageal speech. Oral motor skill was examined in a nonspeech task that involved tongue tip placement at six points along the palate with and without visual feedback. This revealed precise control of the tongue even in the region of the cleft. Less accurate tongue placement skills were found in the central palatal region despite intactness of the palate. This supports the hypothesis that phonetic inventories of human languages are shaped by oral motor capabilities.

Adult↗
PubMed1985

Vocal/verbal response times of normal-hearing and hearing-impaired children.

A series of experiments are reported that contrast vocal/verbal reaction-time measures from 16 normal-hearing and 25 hearing-impaired children 7 to 14 years old. Sixteen of the hearing-impaired children were enrolled in a residential school, 9 in a day school. Vocal reaction time of the children in response to visually presented stimuli was measured in four tasks: phonating "uh", saying the word "one", counting to digits, and naming digits. No significant differences were found between the response latencies of the two hearing-impaired groups on any task. Nor were differences found between the normal and hearing-impaired groups when the task was simply phonating "uh". Differences between these groups began to emerge when the word "one" was spoken. These differences increased systematically with the phonetic complexity of the task. Hearing level, latency in the counting responses, and magnitude of a ratio between phonating and digit counting latencies were identified as major predictors of speech intelligibility. The results suggest that central phonetic processing functions may be related to the quality of speech production by hearing-impaired talkers.

Adolescent↗
PubMed1983

Evaluation of the effects of palatal augmentation on partial glossectomy speech.

Patients who have had surgical removal of part of the tongue are left with varying degrees of speech deficiencies. Augmentation of the palate has been suggested as a means of compensation for this deficiency. This pilot study suggests a technique for evaluating prosthodontic efforts to improve speech for partial glossectomy patients. Although firm conclusions cannot be based on the observations of one patient, it appears that both the shape of the palatal surface and the contour of the cavity size anterior to the tongue are important factors to be considered in prosthodontic efforts to optimize fricative sound production for partial glossectomy patients. Further studies with patients who have a wider variety of tongue resections are indicated. The technique described is an effective one for further studies.

Evaluation Studies as Topic↗
PubMed1983

Speech modification by a deaf child through dynamic orometric modeling and feedback.

Baseline physiologic, acoustic, and phonetic data are presented to characterize speech production of a 3 1/2-year-old deaf girl prior to a visual articulatory modeling and feedback program. These observations suggest that she used an articulatory strategy based on visual information about lip and jaw movements rather than tongue positions as a primary means of differentiating speech sounds. The training program which followed used instrumentally generated displays of tongue position and movements to teach production of the (i) and (a) vowels in single and bisyllable word contexts. Linguapalatal contact patterns for the consonant (t) were then introduced and taught in combinations with the vowels. Goal articulatory gestures were learned rapidly with respect to both positional and timing features of speech.

Articulation Disorders↗
PubMed1980

Performance of children with severe to profound auditory impairment in instrumentally guided reduction of nasal resonance.

Twelve students at the Kentucky School for the Deaf were studied using a bioelectronic instrument to provide visual feedback of the degree of nasal resonance, thereby guiding them toward reduction of excessively nasal voice quality. The subjects were given a maximum of fourteen 20-min sessions of training. The results indicated that the feedback information was used very effectively by five subjects and somewhat effectively by four others. The remaining three subjects did not demonstrate a consistent relationship between periods of training and reduction in nasal resonance. Pre- and post-training testing using stimuli not included in the training material demonstrated significant generalization of the nasalance control gained in the training sessions.

Adolescent↗