Journal of speech and hearing research最新文献

This study investigated the relationship between acoustic damping of hearing aid responses and listeners' speech discrimination and judgments of preference and sound quality. Eighteen subjects with essentially equivalent hearing impairments participated. Subjects' speech discrimination was evaluated for a male talker in quiet and in noise and for a female talker in the same conditions with hearing aids with 0 dB, -5 dB, and -10 dB of damping. Subjects also compared the damping levels using eight bipolar adjective pairs and provided judgments of overall preference. Measurements of the hearing aid responses were made in a 2-cm3 coupler and in the subjects' ears using probe microphone techniques. Smoothness of the responses was quantified using the Index of Response Irregularity (IRI) and the Frequency Response Smoothness Quantification Index (FReSQI). Subjects preferred the two damped hearing aid responses to the undamped. They also had better speech discrimination with damped hearing aid responses. The bipolar adjectives were of limited use in comparing hearing aids. A few questions about hearing aid sound quality and preference appear adequate for evaluating listeners' choice of hearing aids. Smoothness of the hearing aid responses in the test box was higher for the damped hearing aids than for the undamped. However, for real ear responses measured using a probe microphone, smoothness did not change as a function of damping level.

A performance-based model was employed to investigate the impact of discourse demands on the pattern of morphosyntactic deficits exhibited by children with Specific Language Impairments (SLI). The pattern of grammatical errors varied with respect to discourse demands for children with good receptive language abilities but remained stable and independent of changes in discourse demands for children with both expressive and receptive deficits. These findings suggest distinct deficit profiles for subgroups of children with SLI differing in receptive language abilities that are not evident when syntactic skills are investigated outside the context of ongoing spontaneous discourse.

Twenty children who have worn a Cochlear Corporation cochlear implant for an average of 33.6 months participated in a device-on/off experiment. They spoke 14 monosyllabic words three times each after having not worn their cochlear implant speech processors for several hours. They then spoke the same speech sample again with their cochlear implants turned on. The utterances were phonetically transcribed by speech-language pathologists. On average, no difference between speaking conditions on indices of vowel height, vowel place, initial consonant place, initial consonant voicing, or final consonant voicing was found. Comparisons based on a narrow transcription of the speech samples revealed no difference between the two speaking conditions. Children who were more intelligible were no more likely to show a degradation in their speech production in the device-off condition than children who were less intelligible. In the device-on condition, children sometimes nasalized their vowels and inappropriately aspirated their consonants. Their tendency to nasalize vowels and aspirate initial consonants might reflect an attempt to increase proprioceptive feedback, which would provide them with a greater awareness of their speaking behavior.

The perioral reflex in response to innocuous mechanical stimulation of the lip vermilion was studied in 20 young and 20 older women. Responses to stimuli at the right and left sides of both the upper and lower lips were recorded. Results show significant specificity of response, especially for upper lip sites. Reflex response at the site of stimulation was greatest in amplitude and shortest in latency, followed by response at sites ipsilateral to the site of stimulation. Younger subjects showed greater localizing tendency than older subjects. Stimulation was significantly less likely to produce a reflex response in the older group. When reflex responses did occur, they were significantly lower in amplitude and longer in latency than the responses of the younger group. Nonetheless, reflex responses were common in both groups, with responses at the site of stimulation occurring 78% of the time in older women and 90% of the time in younger women. Every participant showed at least one reflex response to lip stimulation. Results suggest decreasing complexity of synaptic drive to the perioral system in old age but also show that reflexive response does not deteriorate completely, remaining an available element for motor control in normal older women.

The present study investigated whether children with specific language impairment (SLI) differed from children with normal language learning in their ability to process binaural temporal information. The SLI group was matched with peers of the same chronological age, as well as peers with similar language age. All three subject groups were tested with measures of complex sound localization involving the precedence effect phenomenon. Subjects were required to track the apparent motion of a "moving" fused auditory image (FAI). Movement of the FAI was simulated by varying the delay incrementally between pairs of clicks presented, one each, from two matched loudspeakers placed on opposite sides of the child's head. With this task, the SLI subjects' performances were found to be similar to their language age-matched but chronologically younger peers. Both groups exhibited tracking skills that were statistically poorer than that of the chronologically age-matched group. Additional tests indicated this effect was not due to differences in motoric tracking abilities nor to the SLI subjects' abilities to perceive small binaural time cues. Thus, children with SLI appear to be impaired in their ability to use binaural acoustic information in a dynamic ongoing fashion. The requirements for processing such nonlinguistic acoustic information in a "dynamic and ongoing" fashion may be similar to those involved in the ongoing processing of rapid changes in the temporal and spectral components of the speech chain.

Developmental apraxia of speech is a disorder of phonological and articulatory output processes. However, it has been suggested that perceptual deficits may contribute to the disorder. Identification and discrimination tasks offer a fine-grained assessment of central auditory and phonetic functions. Seventeen children with developmental apraxia (mean age 8:9, years:months) and 16 control children (mean age 8:0) were administered tests of identification and discrimination of resynthesized and synthesized monosyllabic words differing in place-of-articulation of the initial voiced stop consonants. The resynthetic and synthetic words differed in the intensity of the third formant, a variable potentially enlarging their clinical value. The results of the identification task showed equal slopes for both subject groups, which indicates no phonetic processing deficit in developmental apraxia of speech. The hypothesized effect of the manipulation of the intensity of the third formant of the stimuli was not substantiated. However, the children with apraxia demonstrated poorer discrimination than the control children, which suggests affected auditory processing. Furthermore, analyses of discrimination performance and articulation data per apraxic subject demonstrated a specific relation between the degree to which auditory processing is affected and the frequency of place-of-articulation substitutions in production. This indicates the interdependence of perception and production. The results also suggest that the use of perceptual tasks has significant clinical value.

Estimates of cochlear traveling wave velocity (TWV) were computed from derived-band auditory brain-stem response (ABR) latencies in subjects with noise-induced hearing loss (NIHL) or Meniére's disease (MD). ABR wave V latencies were determined for each of six derived frequency bands (unmasked-8 kHz, 8-4 kHz, 4-2 kHz, 2-1 kHz, 1 kHz-500 Hz, and 500-250 Hz). Representative frequencies were assigned to the derived bands by estimating their energy midpoints, and cochlear positions corresponding to these frequencies were determined using Greenwood's (1961) place-frequency function for humans. An exponential function of the form I = A + BeCd was fitted to each subject's latency-by-distance data using a least-squares algorithm, and a TWV function was generated by taking the reciprocal of the derivative of the latency function with respect to distance [v = 1/(BCeCd)]. Expected values for subjects' TWV functions were compared to normative data from Donaldson and Ruth (1993) at five cochlear loci. NIHL subjects' TWV estimates fell within normal limits at all cochlear loci, and no relation between severity of high-frequency hearing loss and TWV could be discerned. MD subjects with good low-frequency hearing sensitivity generally yielded normal TWV estimates, whereas MD subjects with low-frequency hearing loss yielded either normal or elevated TWVs. MD subjects' data generally support the hypothesis that endolymphatic hydrops results in increased TWV or, alternatively, a basalward shift in the peak of the traveling wave, in cochleas with presumed normal basilar membrane elasticity.

A 3-year longitudinal study of the language performance of children from poverty was designed to address the problem of separating children with a specific language impairment (SLI) from low-scoring normal children in the borderline area on the continuum of language performance where normal ends and abnormal begins. Two approaches to definition were compared: an experimental approach (using story-retelling, rote-memory ability, and invented-morpheme learning) and a traditional approach (using standardized-test discrepancy scores). Results indicated that 6 of 34 children tracked from kindergarten through second grade appeared to be SLI at the end of the study. The best kindergarten predictor for the outcome status of these 6 children was a combination of the score on the Oral Vocabulary subtest of the TOLD-2P and the score on a combination of the experimental tasks. The best single kindergarten predictor of the academic status of the 15 children in the study who received academic remediation was story-retelling. Children's scores on the experimental and standardized tests of language performance and nonverbal intelligence were profiled over the 3 years of the study, and patterns of change in many instances reveal the lifting of the early influences of poverty.

The contribution of reduced speaking rate to the intelligibility of "clear" speech (Picheny, Durlach, & Braida, 1985) was evaluated by adjusting the durations of speech segments (a) via nonuniform signal time-scaling, (b) by deleting and inserting pauses, and (c) by eliciting materials from a professional speaker at a wide range of speaking rates. Key words in clearly spoken nonsense sentences were substantially more intelligible than those spoken conversationally (15 points) when presented in quiet for listeners with sensorineural impairments and when presented in a noise background to listeners with normal hearing. Repeated presentation of conversational materials also improved scores (6 points). However, degradations introduced by segment-by-segment time-scaling rendered this time-scaling technique problematic as a means of converting speaking styles. Scores for key words excised from these materials and presented in isolation generally exhibited the same trends as in sentence contexts. Manipulation of pause structure reduced scores both when additional pauses were introduced into conversational sentences and when pauses were deleted from clear sentences. Key-word scores for materials produced by a professional talker were inversely correlated with speaking rate, but conversational rate scores did not approach those of clear speech for other talkers. In all experiments, listeners with normal hearing exposed to flat-spectrum background noise performed similarly to listeners with hearing loss.

Thirty children (mean age 6:11, range 4:3 to 11:0, SD = 2:3) with profound hearing impairments were followed longitudinally over a 3-year period and evaluated every 6 months with a battery of speech perception tests. The battery spanned several levels of perception, from pattern perception to open-set word recognition. The children were all enrolled in a single full-day educational program that used multichannel tactile aids in addition to hearing aids. Testing was conducted in Auditory alone (A), Tactile plus Auditory (TA), Tactile alone (T), and in one instance, Tactile plus Auditory plus Vision (TAV) conditions because the primary interest of the work was the relationship between auditory and tactile training on perception. Results indicated that children's performance improved with age, with the oldest children achieving open-set speech recognition in the TA condition. Performance in the TA condition generally exceeded that in both A and T conditions. Outcomes were compared to those from two studies in the literature for children of similar age with cochlear implants and tactile aids on the same tests. Results suggest that performance of children who had cochlear implants for an average of 21 months was similar to TA and TAV performance of children in the present study who had tactile experience over a similar period.