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At least 469 records · Page 26Linked to original sources
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↗
PubMed1995

Acoustic-phonetic context considerations for speech recognition testing of hearing-impaired listeners.

OBJECTIVE: To test for differences in the identification of consonants in carrier sentences versus in VCVs extracted from the sentences, as a function of listeners' hearing-loss categories: moderate, severe, profound. To examine whether pauses inserted in the sentences will facilitate identification of the consonants. DESIGN: Voiced stops and fricatives were identified by 11 listeners with moderate hearing losses and by 7 listeners with severe losses (between subjects design) for the conditions of consonants in sentences and in VCVs extracted from the sentences (repeated measures). Nine of these listeners also identified the consonants in the sentences with pauses. Six normal-hearing listeners were tested for the consonants in the extracted VCVs and the sentences. Voiceless stops and fricatives were identified by 4 listeners with profound losses, 18 with severe losses, and 8 with moderate losses (between subjects) for the conditions of extracted VCVs and the sentences (repeated measures). All listeners were selected on the basis of their hearing levels. RESULTS: The listeners with moderate to severe hearing loss identified the voiced stops and fricatives more poorly when the syllables were in the carrier sentences than when extracted. Insertion of the pauses in the sentence did not improve performance significantly. The normal hearing listeners showed no differences in consonant identification between the two conditions, perhaps due to "ceiling effects". The voiceless stops and fricatives were also identified more poorly when in the extracted VCVs than in the carrier sentences by other listeners with moderate to profound hearing loss. CONCLUSIONS: Listeners with moderate or greater hearing loss can show poorer identification of consonants that are embedded midway in carrier sentences than when the acoustically identical consonants are in VCVs extracted from the sentences. The performance reduction for the consonants in sentences is not relieved from insertion of brief artificial pauses in the sentences. Further research is needed determine whether hearing-impaired listeners' identification of consonants in target words of clinical word recognition tests is facilitated when the words are extracted from carrier phrases.

Audiometry, Pure-Tone↗
PubMed2006

Phonetic mismatch negativity predicts verbal memory deficits in schizophrenia.

Deficits in auditory sensory memory at the electrophysiological level as indexed by mismatch negativity and those in auditory verbal memory at the neuropsychological level have been independently demonstrated in previous studies of schizophrenia. We predicted a specific association between these indices in schizophrenia. Mismatch negativities elicited by change in tone duration and phoneme duration were recorded in 23 schizophrenia patients, who were also evaluated for auditory verbal memory and executive function. Lower amplitude of mismatch negativity under the phoneme-duration condition was significantly associated with worse verbal memory. Phoneme-duration mismatch negativity was not correlated with executive function, nor was tone-duration mismatch negativity correlated with verbal memory. These results suggest that electrophysiological auditory sensory memory dysfunction underlies the basis for neuropsychological auditory verbal memory deficits in schizophrenia.

Adult↗
PubMed2005

Phonetic identification in quiet and in noise by listeners with cochlear implants.

This study examined the effect of noise on the identification of four synthetic speech continua (/ra/-/la/, /wa/-/ja/, /i/-/u/, and say-stay) by adults with cochlea implants (CIs) and adults with normal-hearing (NH) sensitivity in quiet and noise. Significant group-by-SNR interactions were found for endpoint identification accuracy for all continua except /i/-/u/. The CI listeners showed the least NH-like identification functions for the /ra/-/la/ and /wa/-/ja/ continua. In a second experiment, NH adults identified four- and eight-band cochlear implant stimulations of the four continua, to examine whether group differences in frequency selectivity could account for the group differences in the first experiment. Number of bands and SNR interacted significantly for /ra/-/la/, /wa/-/ja/, and say-stay endpoint identification; strongest effects were found for the /ra/-/la/ and say-stay continua. Results suggest that the speech features that are most vulnerable to misperception in noise by listeners with CIs are those whose acoustic cues are rapidly changing spectral patterns, like the formant transitions in the /wa/-/ja/ and /ra/-/la/ continua. However, the group differences in the first experiment cannot be wholly attributable to frequency selectivity differences, as the number of bands in the second experiment affected performance differently than suggested by group differences in the first experiment.

Acoustic Stimulation↗
PubMed1978

Perceptibility of phonetic features in fluent speech.

A series of experiments examined listeners' ability to detect mispronounced words in a short story. Mispronunciations were produced by changing a single consonant segment in a word to produce a (phonologically permissible) nonsense word. The results of six different experiments showed that prestressed work-initial stop consonants are more perceptible than other consonants. For example, mispronunciations produced by changing the voicing of a word-initial stop (e.g., "boy" to "poy") were detected about 70% of the time, while changes in voicing of a word-initial fricative (e.g., "voice" to "foice") were detected about 38% of the time. Mispronunciations produced by changing the place of articulation of a prestressed word-initial stop were most detectable of all (80% to 90% detection) for three different speakers. A change in place of articulation of a word-initial stop (e.g., "baby" to "daby") was detected as often as a change in both place of articulation and voicing (e.g., "baby" to "taby"). Finally, it was found that a mispronunciation was detected about twice as often in word-initial than in word-final position in one syllable words for both stops and nasals. The results suggest that listeners pay special attention to word-initial stop consonants in natural continuous speech.

Humans↗
PubMed1979

Some experiments on the sound of silence in phonetic perception.

The results of several experiments demonstrate that silence is an important cue for the perception of stop-consonant and affricate manner. In some circumstances, silence is necessary; in others, it is sufficient. But silence is not the only cue to these manners. There are other cues that are more or less equivalent in their perceptual effects, though they are quite different acoustically. Finally, silence is effective as a cue when it separates utterances produced by male and female speakers. These findings are taken to imply that, in these instances, perception is constrained as if by some abstract conception of what vocal tracts do when they make linguistically significant gestures.

Cues↗
PubMed1980

Acoustic correlates of some phonetic categories.

Some of the acoustic properties that distinguish one speech sound from another are reviewed. The point of view is that the auditory system responds to sound with different acoustic properties in distinctive ways, and that these special responses play an important role in selection and classification of the inventory of sounds that are used in language. Examples of several of these acoustic properties are discussed and illustrated, including the presence or absence of rapid spectrum change, abruptness and amplitude change, voicing and aspiration, and gross spectral properties relating to place of articulation for consonant and vowels.

Humans↗
PubMed1981

Shifts in phonetic identification with changes in signal presentation level.

Identification functions for stimuli from a two-formant [bdg] continuum were assessed at three levels of signal presentation: 55, 70, and 90 dB SPL. At 90 dB the [b] category was narrowed, the [d] category virtually eliminated, and the [g] category greatly enlarged. Since high SPLs can alter the identification functions for these simplified speech signals, caution should be exercised when using stimuli of this nature to compare the speech perception abilities of normal hearing and hearing impaired listeners. If high SPLs, independent of cochlear damage, can alter identification functions, then perceptual experiments may best be conducted at equal SPLs rather than at equal SLs.

Hearing Loss, Sensorineural↗