Biomedical subjects

V Hazan

Publications and source records attributed to V Hazan.

9 recordsLinked to original sources

PubMed1999

Speech pattern audiometry in hearing impaired children.

The aim of this study was to investigate the use of speech pattern audiometry (SPA) in assessing speech perception abilities of a group of 25 children with sensorineural hearing loss, and to compare their aided performance on SPA tests of four different phoneme contrasts with scores achieved on recorded Manchester Junior Word Lists (MJWL) at their most comfortable listening level (MCLL). The listeners were 25 children, 19 with congenital and six with acquired hearing loss aged between eight and 14 years. They were classified into three groups according to the severity of the hearing loss in the better hearing ear (20-60 dB HL, 61-80 dB HL and >81 dB HL). The SPA tests evaluated listeners' ability to identify word-initial plosives differing in the phonetic features of voicing and place of articulation. The main outcome measures were the SPA gradient measures, the SPA labelling function configuration and MJWL scores. The group with the most severe hearing loss (>81 dB HL) showed significantly poorer performance on the SPA tests and MJWL tests than the groups with mild (20-60 dB HL) to moderate (61-80 dB HL) hearing losses. There was significantly better performance on the two plosive voicing contrast tests than the two plosive place contrasts. For the MJWL, the performance of the group with the more severe hearing loss was also significantly different from the mild and moderate hearing loss groups. A MJWL score of up to 75% was associated with the random labelling configuration on all four SPA tests, emphasizing the different aspects of speech perception that were being examined with each type of test. This study suggests that there is a place for SPA as part of the test battery for speech perception testing in hearing-impaired children.

Child↗

PubMed1998

Speech perception in children with specific reading difficulties (dyslexia).

Many experimental studies over the last two decades have suggested that groups of children who suffer significant delay in reading also show a weakness in phoneme discrimination and identification. In order to look further at the relation between type of reading deficit, auditory acuity, and speech discrimination, a group of 13 children with specific reading difficulty (SRD), 12 chronological-age controls, and 12 reading-age controls were tested on a battery of speech-perceptual, psychoacoustic, and reading tests. A sub-group of children with Specific Reading Difficulty (SRD) were poor at speech discrimination tests, whereas the rest of the SRD group performed within norms. For this sub-group, discrimination performance was particularly poor for consonant contrasts differing in a single feature that was not acoustically salient, and problems were encountered with nasal and fricative contrasts as wells with stop contrasts. These children did not differ from controls in their performance on non-speech psychoacoustic tasks. An evaluation is made of the reported phonemic awareness skills of beginning readers with regard to speech-processing issues which may help in understanding what factors are important in reading development.

Attention↗

PubMed1995

Speech pattern audiometry for clinical use.

A new PC-based speech perception testing system ('speech pattern audiometer') is described which aims to provide a simple and efficient clinical tool to assess patients' ability to make use of the acoustic speech pattern information which is fundamental to speech perception. The speech pattern audiometer is likely to find its main application in audiology and speech and language therapy clinics with those who are deaf or who have developmental or acquired speech-perceptual disorders. This system constitutes a module of a complete speech and hearing assessment and teaching/therapy workstation.

Audiometry, Speech↗

PubMed1995

Temporal and spectral cue use for initial plosive voicing perception by hearing-impaired children and normal-hearing children and adults.

The influence of voice-onset time (VOT) and vowel-onset characteristics on the perception of the voicing contrast for initial plosive consonants was examined for hearing-impaired children, and normal-hearing children and adults. Listeners identified spoken 'DAD'--'TAD' stimuli controlled for VOT and vowel onset characteristics. Only six of 16 hearing-impaired children appropriately identified the exemplar DAD and TAD stimuli used as endpoints of VOT continua. For this group of six hearing-impaired children, a longer VOT than for the normal-hearing listeners was required to elicit /t/ rather than /d/ percepts. The VOT region of perceptual cross-over in labelling widened progressively from normal-hearing adults to normal-hearing children to hearing-impaired children. Generally, longer VOTs were required to yield /t/ perception in the context of the DAD vowel than with the TAD vowel. These 'vowel stem' effects on VOT boundary were inconsistent for the hearing-impaired children, and weaker for the normal-hearing children than for the adults. These spoken stimuli produced results for VOT cue use that generally parallel those obtained in studies with synthetic stimuli.

Adult↗

PubMed1991

Development of phonetic labeling in hearing-impaired children.

The development of labeling ability of an unselected group of 16 severely to profoundly hearing-impaired children was assessed over a period of 4 years, using synthetic speech pattern tests of increasing acoustic complexity. Detailed results are presented for six children matched in pairs in terms of their average pure-tone thresholds. All children showed progress in their ability to label at least some of the contrasts. Development was usually seen for the vowel contrast before the more complex initial consonant voicing contrast. Rate of development was not closely related to average pure-tone thresholds.

Child↗

PubMed1991

Individual variability in the perception of cues to place contrasts in initial stops.

Synthetic continua of two minimal pairs, BAIT-DATE and DATE-GATE, closely modeled on natural utterances by a female speaker, were presented to a group of 16 listeners for identification in full-cue and reduced-cue conditions. Grouped results showed that categorization curves for full- and reduced-cue conditions differed significantly in both contrasts. However, an averaging of results obscures marked variability in labeling behavior. Some listeners showed large changes in categorization between the full- and reduced-cue conditions, whereas others showed relatively small or no changes. In a follow-up study, perception of the BAIT-DATE contrast was compared with the perception of a highly stylized BA-DA continuum. A smaller degree of intersubject and between-condition variability was found for these less complex synthetic stimuli. The amount of variability found in the labeling of speech contrasts may be dependent on cue salience, which will be determined by the speech pattern complexity of the stimuli and by the vowel environment.

Adult↗

PubMed1985

Microprocessor-controlled speech pattern audiometry. Preliminary results.

Interactive microprocessor-controlled speech pattern tests making use of high-quality synthetic speech have been used to assess the development of subjects' ability to process speech contrasts of increasing complexity, from prosodic contrasts to a 'date-gate' place contrast. These tests have been particularly useful in mapping the development or recovery of subjects functioning at the very first stages of processing ability. Some results obtained with profoundly hearing-impaired children and with adults suffering from brain stem disorders are reported, and further applications of speech pattern audiometric techniques are briefly discussed.

Adolescent↗

PubMed1985

Audiological rehabilitation of patients with brainstem disorders.

A brief account is given of the course of rehabilitation of three patients with severe brainstem injuries. Particular use has been made of synthetic speech pattern assessment procedures which have been integrated into the management model of Goldstein and Stephens (1981). The use of speech stimuli of controllable simplicity has two main clinical benefits: the early course of re-acquisition can be examined analytically, second, aspects of speech receptive and productive rehabilitation can be facilitated. Re-acquisition of perceptive ability in some of these patients may follow a progression from simple to complex acoustic pattern contrasts and this may provide an effective basis for future techniques of rehabilitation.

Adult↗

PubMedDate not supplied

The effect of cue-enhancement on consonant intelligibility in noise: speaker and listener effects.

Our previous work (Hazan & Simpson, 1998) has shown that increasing the salience of perceptually important regions of nonsense word and sentence materials aids speech perception in noise. This study aimed to extend these findings by investigating the robustness of these enhancement techniques in improving consonant intelligibility for a range of different speakers and for groups of listeners with different language backgrounds. In Experiment 1, nonsense vowel-consonant-vowel (VCV) tokens produced by two female and two male speakers without phonetic training were annotated to highlight segments of the signal corresponding to the consonant constriction/occlusion and vowel onset/offset regions. These regions were selectively amplified to enhance the cues they contained, then combined with speech-shaped noise at 0 dB SNR and presented to normally hearing listeners. Significant improvements in intelligibility were found for all speakers although the extent of the improvement varied across speakers. In Experiment 2, a subset of these stimuli were presented to two groups of learners of English--a Japanese-L1 group and a Spanish-L1 group--and a new group of native-English controls. Results showed a significant effect of enhancement in all listener-groups and similar speaker effects for the non-native and native English listeners. Error patterns were related to the distance between the phonological systems of listeners' L1 and L2.

Adult↗