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Purpose: The change/no-change procedure (J. E. Sussman & A. E. Carney, 1989), which assesses speech discrimination, has been used under the assumption that the number of stimulus presentations does not influence performance. Motivated by the tenets of the multiple looks hypothesis (N. F. Viemeister & G. H. Wakefield, 1991), work by R. F. Holt and A. E. Carney (2005) called this assumption into question (at least for adults): Nonsense syllable discrimination improved with more stimulus presentations. This study investigates the nature of developmental differences and the effects of multiple stimulus presentations in the change/no-change procedure. Method: Thirty normal-hearing children, ages 4.0-5.9 years, were tested on 3 consonant-vowel contrasts at various signal-to-noise ratios using combinations of 2 and 4 standard and comparison stimulus repetitions. Results: Although performance fell below that which is predicted by the multiple looks hypothesis in most conditions, discrimination was enhanced with more stimulus repetitions for 1 speech contrast. The relative influence of standard and comparison stimulus repetitions varied across the speech contrasts in a manner different from that of adults. Conclusion: Despite providing no additional sensory information, multiple stimulus repetitions enhanced children's discrimination of 1 set of nonsense syllables. The results have implications for models of developmental speech perception and assessing speech discrimination in children.

N. F. Viemeister and G. H. Wakefield's (1991) multiple looks hypothesis is a theoretical approach from the psychoacoustic literature that has promise for bridging the gap between results from speech perception research and results from psychoacoustic research. This hypothesis accounts for sensory detection data and predicts that if the "looks" at a stimulus are independent and information is combined optimally, sensitivity should increase for 2 pulses relative to 1 pulse. Specifically, d' (a bias-free measure of sensitivity) for 2 pulses should be larger than d' for 1 pulse. One speech discrimination paradigm that presents stimuli with multiple presentations is the change/no-change procedure. On a change trial, the standard and comparison stimuli differ; on a no-change trial, they are the same. Normal-hearing adults were tested using the change/no-change procedure with 3 consonant-vowel minimal pairs in combinations of 1, 2, and 4 repetitions of standard and comparison stimuli at various signal-to-noise ratios. If multiple looks extend to this procedure, performance should increase with higher repetition numbers. Performance increased with more presentations of the speech contrasts tested. The multiple looks hypothesis predicted performance better at low repetition numbers when performance was near d' values of 1.0 than at higher repetition numbers and higher performance levels. (Contains 9 figures and 2 tables.)

This study examined spoken word recognition in adults with cochlear implants (CIs) to determine the extent to which linguistic and cognitive abilities predict variability in speech-perception performance. Both a traditional consonant-vowel-consonant (CVC)-repetition measure and a gated-word recognition measure (F. Grosjean, 1996) were used. Stimuli in the gated-word-recognition task varied in neighborhood density. Adults with CIs repeated CVC words less accurately than did age-matched adults with normal hearing sensitivity (NH). In addition, adults with CIs required more acoustic information to recognize gated words than did adults with NH. Neighborhood density had a smaller influence on gated-word recognition by adults with CIs than on recognition by adults with NH. With the exception of 1 outlying participant, standardized, norm-referenced measures of cognitive and linguistic abilities were not correlated with word-recognition measures. Taken together, these results do not support the hypothesis that cognitive and linguistic abilities predict variability in speech-perception performance in a heterogeneous group of adults with CIs. Findings are discussed in light of the potential role of auditory perception in mediating relations among cognitive and linguistic skill and spoken word recognition.

A review of the research on treatment efficacy for children with hearing loss found that early intervention has long-term positive effects; that a variety of communication modalities exist and research has been more descriptive than prognostic on the choice of modality; and that sensory aids provide different degrees of benefit. (Author/CR)

When assessing the speech production of children, researchers or clinicians use a variety of speech elicitation tasks such as asking the child to name a picture or object or to [...], Given the interest in comparing speech production development in children with normal hearing and hearing impairment, it is important to evaluate how variables within speech elicitation tasks can differentially affect the acoustics of speech production for these groups. In a first experiment, children (6-14 years old) with cochlear implants produced a set of monosyllabic words either in isolation or while simultaneously signing the word. Acoustical analyses indicated no change in word duration, voice onset time, intensity, or fundamental frequency between isolated and simultaneous signing conditions. In a second experiment, the same children verbally repeated words that were signed by a video model. The model either signed with inflection or without. Words repeated after inflected models were higher in fundamental frequency and intensity and were more intelligible. In addition, children with poorer speech perception skills sometimes produced the monosyllables as 2 syllables, but this only occurred for words that had multiple sign movements. The results have implications for the comparison of speech development between children with normal hearing and those with hearing impairment. KEY WORDS: speech production, cochlear implants, acoustics, simultaneous communication

Previous studies have shown that manipulation of a particular frequency region of the consonantal portion of a syllable relative to the amplitude of the same frequency region in an adjacent vowel influences the perception of place of articulation. This manipulation has been called the relative amplitude cue. Earlier studies have examined the effect of relative amplitude and formant transition manipulations upon labeling place of articulation for fricatives and stop consonants in listeners with normal hearing. The current study sought to determine if (a) the relative amplitude cue is used by adult listeners wearing a cochlear implant to label place of articulation, and lb) adult listeners wearing a cochlear implant integrated the relative amplitude and formant transition information differently than listeners with normal hearing. Sixteen listeners participated in the study, 12 with normal hearing and 4 postlingually deafened adults wearing the Nucleus 22 electrode Mini Speech Processor implant with the multipeak processing strategy. The stimuli used were synthetic consonant-vowel (CV) syllables in which relative amplitude and formant transitions were manipulated. The two speech contrasts examined were the voiceless fricative contrast/s/-/j/and the voiceless stop consonant contrast/p/-/t/. For each contrast, listeners were asked to label the consonant sound in the syllable from the two response alternatives. Results showed that (a) listeners wearing this implant could use relative amplitude to consistently label place of articulation, and (b) listeners with normal hearing integrated the relative amplitude and formant transition information more than listeners wearing a cochlear implant, who weighted the relative amplitude information as much as 13 times that of the transition information. KEY WORDS: cochlear implants, speech perception, consonant perception, deafness, integration of acoustic cues

Methods of measuring speech intelligibility in hearing impaired students are reviewed; factors affecting speech intelligibility, such as segmental speech production and listener experience are considered; and implications for clinical management are noted. (CL)

Two speech perception experiments were conducted with 12 normally hearing adults using a modified speech tracking procedure to determine the effects of controlling connected discourse materials and the effects of specific prompting techniques on tracking rate and subjects' responses. Results showed higher tracking rates for controlled materials. (Author/JDD)

The recognition performance for segmental stimuli was compared when presented through a single-channel tactile device and through a 24-channel vocoder. Both consonant and vowel stimuli were tested under visual only, tactile only, and visual/tactile conditions. Results indicated no significant performance differences for the 12 artificially deafened listeners. (Author/JDD)

The study examined whether children with normal linguistic skills demonstrate increasing developmental changes in their perception of place of articulation for stop consonants with short- and long-duration formant transitions. Children's improving discrimination abilities did not reach adult levels even at 10 years of age. (Author/DB)

Investigates the perception and production of voice onset time (VOT) in a Thai patient with sensorineural hearing loss. Exhibit of a three-category voicing distinction for bilabial and alveolar stops; Measurement of VOT perception in labeling responses to synthetic speech; Evaluation of VOT production in word initial stops produced in isolation.

Simultaneous psychophysical tuning curves were obtained from normal-hearing and hearing-impaired listeners, using probe tones that were either at similar sound pressure levels or at similar sensation levels for the two types of listeners. Tuning curves from the hearing-impaired listeners were flat, erratic, broad, and/or inverted, depending upon the frequency region of the probe tone and the frequency characteristics of the hearing loss. Tuning curves from the normal-hearing listeners at low-SPL's were sharp as expected; tuning curves at high-SPL's were discontinuous. An analysis of high-SPL tuning curves suggests that tuning curves from normal-hearing listeners reflect low-pass filter characteristics instead of the sharp bandpass filter characteristics seen with low-SPL probe tones. Tuning curves from hearing-impaired listeners at high-SPL probe levels appear to reflect similar low-pass filter characteristics, but with much more gradual high-frequency slopes than in the normal ear. This appeared as abnormal downward spread of masking. Relatively good temporal resolution and broader tuning mechanisms were proposed to explain inverted tuning curves in the hearing-impaired listeners. [ABSTRACT FROM AUTHOR]

The discriminability of bilabial stop consonants differing in VOT (the Abramson-Lisker bilabial series) was measured in a same-different task, an oddity task, and a dual response, discrimination-identification task. Subjects showed excellent within-category discrimination in all three tasks after a moderate amount of training in a same-different task with a fixed standard and with feedback. In addition, discrimination performance continuously improved with increasing stimulus difference for both intra- and intercategory comparisons. Also, subjects were able to alter their identification responses so that well-defined category boundaries fell at arbitrary values determined by the experimenters. These results are not compatible with a strict interpretation of the categorical perception of stop consonants. [ABSTRACT FROM AUTHOR]

A philosophy of the (re)habilitation of patients with sensorineural hearing losses from a communication point of view is presented. Pediatric and adult populations are discussed separately. Topics of consideration for pediatric patients include the appropriate use of amplification, team management of the hearing handicap, educational placement and the importance of parent counseling. The discussion of the management of adult patients reviews some problems in hearing aid fitting, patient counseling and appropriate case follow-up. The guiding principle behind these (re)habilitation processes is the integration of the hearing-impaired patient into a hearing world. [ABSTRACT FROM AUTHOR]

The recognition of three suprasegmental aspects of speech-the number of syllables in a word, the stress pattern of a word, and rising or falling intonation patterns-through a single-channel tactile device and through a 24-channel tactile vocoder, using two groups of normal-hearing subjects, was compared. All subjects received an initial pretest on three recognition tasks, one for each prosodic feature. Half the subjects from each group then received 12 h of training with feedback on the tasks and stimuli used in the pretest. All subjects received a post-test which contained physically different stimuli from those previously tested. Performance was significantly better on the syllable-number and syllabic stress tasks with the single-channel than with the multichannel device on both the pre- and post-tests; no difference was found for the intonation task. Performance on the post-test was poorer for all trained subjects compared to their final training results, suggesting that cues learned in training were not readily transferable to new stimuli, even those with similar prosodic characteristics. Overall, the results provide support for the notion that certain prosodic features of speech may be conveyed more readily when the waveform envelope is preserved. [ABSTRACT FROM AUTHOR]