Archive for January 11th, 2008
Posted by Callier Library on January 11, 2008
from the Journal of Deaf Studies and Deaf Education
This article reports the findings of balanced and interactive writing instruction used with 16 deaf and hard-of-hearing students. Although the instruction has been used previously, this was the first time it had been modified to suit the specific needs of deaf children and the first time it had been implemented with this subpopulation of students. The intervention took place in two elementary classrooms (N =
and one middle school classroom (N =
for a total of 21 days. A comparison of pre- and posttest scores on both writing and reading measures evidenced that students made significant gains with use of genre-specific traits, use of contextual language, editing/revising skills, and word identification. Students showed neither gains nor losses with conventions and total word count. In addition, a one-way multiple analysis of variance was used to detect any school-level effects. Elementary students made significantly greater gains with respect to conventions and word identification, and middle school students made significantly greater gains with editing and revising tasks.
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Posted by Callier Library on January 11, 2008
from the European Journal of Special Needs Education
This paper reports the results of a study which has been carried out for the first time in Cyprus, with the aim of exploring the views of deaf and hard-of-hearing (D/HH) children (who attend secondary general schools, and use an auditory/oral approach), as well as the perceptions of their parents, teachers and head teachers on their academic and social inclusion. For the purposes of this study, four questionnaires were designed to be administered to all D/HH children attending secondary general schools (n = 69), as well as to their parents (n = 61), to their teachers (n = 367) and to their head teachers (n = 34) with a view to investigating their perceptions on inclusion. The data were analysed statistically and they revealed that the majority of the D/HH children had been included well socially and had achieved a reasonable academic standard. Our study also brought out that the D/HH children’s communicative skills were positively related to their academic and social inclusion. It was shown that D/HH children’s academic inclusion has been facilitated by a number of resources provided, the most important being pre-tutoring sessions, in-service training provided for designated teachers, and modification of normal classroom delivery. Deaf awareness of hearing children and general teachers were also found to be positively related with D/HH children’s social inclusion.
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Posted by Callier Library on January 11, 2008
from the European Journal of Special Needs Education
This study examined the susceptibility to problems with peer relationships and being bullied in a UK sample of 12-year-old children with a history of specific speech and language difficulties. Data were derived from the children’s self-reports and the reports of parents and teachers using measures of victimisation, emotional and behavioural difficulties, prosocial development and self-esteem, together with measures of the children’s language development. Similar prevalence rates for victimisation were found compared with matched groups of typically developing children and children with special educational needs related to general learning difficulties. The importance of prosocial skills and their relationship with language development, particularly pragmatic impairment, are explored.
Posted in Uncategorized | Tagged: language, SLI, speech | Leave a Comment »
Posted by Callier Library on January 11, 2008
from the Journal of the Acoustical Society of America
Several experiments are described in which synthetic monophthongs from series varying between /i/ and /u/ are presented following filtered precursors. In addition to F(2), target stimuli vary in spectral tilt by applying a filter that either raises or lowers the amplitudes of higher formants. Previous studies have shown that both of these spectral properties contribute to identification of these stimuli in isolation. However, in the present experiments we show that when a precursor sentence is processed by the same filter used to adjust spectral tilt in the target stimulus, listeners identify synthetic vowels on the basis of F(2) alone. Conversely, when the precursor sentence is processed by a single-pole filter with center frequency and bandwidth identical to that of the F(2) peak of the following vowel, listeners identify synthetic vowels on the basis of spectral tilt alone. These results show that listeners ignore spectral details that are unchanged in the acoustic context. Instead of identifying vowels on the basis of incorrect acoustic information, however (e.g., all vowels are heard as /i/ when second formant is perceptually ignored), listeners discriminate the vowel stimuli on the basis of the more informative spectral property.
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Posted by Callier Library on January 11, 2008
from the Journal of the Acoustical Society of America
The present study evaluated auditory-visual speech perception in cochlear-implant users as well as normal-hearing and simulated-implant controls to delineate relative contributions of sensory experience and cues. Auditory-only, visual-only, or auditory-visual speech perception was examined in the context of categorical perception, in which an animated face mouthing ba, da, or ga was paired with synthesized phonemes from an 11-token auditory continuum. A three-alternative, forced-choice method was used to yield percent identification scores. Normal-hearing listeners showed sharp phoneme boundaries and strong reliance on the auditory cue, whereas actual and simulated implant listeners showed much weaker categorical perception but stronger dependence on the visual cue. The implant users were able to integrate both congruent and incongruent acoustic and optical cues to derive relatively weak but significant auditory-visual integration. This auditory-visual integration was correlated with the duration of the implant experience but not the duration of deafness. Compared with the actual implant performance, acoustic simulations of the cochlear implant could predict the auditory-only performance but not the auditory-visual integration. These results suggest that both altered sensory experience and improvised acoustic cues contribute to the auditory-visual speech perception in cochlear-implant users.
Posted in Uncategorized | Tagged: cochlear implants, hearing, speech perception | Leave a Comment »
Posted by Callier Library on January 11, 2008
from the Journal of the Acoustical Society of America
Noise vocoding was used to investigate the ability of younger and older adults with normal audiometric thresholds in the speech range to use amplitude envelope cues to identify words. In Experiment 1, four 50-word lists were tested, with each word presented initially with one frequency band and the number of bands being incremented until it was correctly identified by the listener. Both age groups required an average of 5.25 bands for 50% correct word identification and performance improved across the four lists. In Experiment 2, the same participants who completed Experiment 1 identified words in four blocked noise-vocoded conditions (16, 8, 4, 2 bands). Compared to Experiment 1, both age groups required more bands to reach the 50% correct word identification threshold in Experiment 2, 6.13, and 8.55 bands, respectively, with younger adults outperforming older adults. Experiment 3 was identical to Experiment 2 except the participants had no prior experience with noise-vocoded speech. Again, younger adults outperformed older adults, with thresholds of 6.67 and 8.97 bands, respectively. The finding of age effects in Experiments 2 and 3, but not in Experiment 1, seems more likely to be related to differences in the presentation methods than to experience with noise vocoding.
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Posted by Callier Library on January 11, 2008
from the Journal of the Acoustical Society of America
Recognition of isolated monosyllabic words in quiet and recognition of key words in low- and high-context sentences in babble were measured in a large sample of older persons enrolled in a longitudinal study of age-related hearing loss. Repeated measures were obtained yearly or every 2 to 3 years. To control for concurrent changes in pure-tone thresholds and speech levels, speech-recognition scores were adjusted using an importance-weighted speech-audibility metric (AI). Linear-regression slope estimated the rate of change in adjusted speech-recognition scores. Recognition of words in quiet declined significantly faster with age than predicted by declines in speech audibility. As subjects aged, observed scores deviated increasingly from AI-predicted scores, but this effect did not accelerate with age. Rate of decline in word recognition was significantly faster for females than males and for females with high serum progesterone levels, whereas noise history had no effect. Rate of decline did not accelerate with age but increased with degree of hearing loss, suggesting that with more severe injury to the auditory system, impairments to auditory function other than reduced audibility resulted in faster declines in word recognition as subjects aged. Recognition of key words in low- and high-context sentences in babble did not decline significantly with age.
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Posted by Callier Library on January 11, 2008
from the Journal of the Acoustical Society of America
Perceptual coherence, the process by which the individual elements of complex sounds are bound together, was examined in adult listeners with longstanding childhood hearing losses, listeners with adult-onset hearing losses, and listeners with normal hearing. It was hypothesized that perceptual coherence would vary in strength between the groups due to their substantial differences in hearing history. Bisyllabic words produced by three talkers as well as comodulated three-tone complexes served as stimuli. In the first task, the second formant of each word was isolated and presented for recognition. In the second task, an isolated formant was paired with an intact word and listeners indicated whether or not the isolated second formant was a component of the intact word. In the third task, the middle component of the three-tone complex was presented in the same manner. For the speech stimuli, results indicate normal perceptual coherence in the listeners with adult-onset hearing loss but significantly weaker coherence in the listeners with childhood hearing losses. No differences were observed across groups for the nonspeech stimuli. These results suggest that perceptual coherence is relatively unaffected by hearing loss acquired during adulthood but appears to be impaired when hearing loss is present in early childhood.
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Posted by Callier Library on January 11, 2008
from the Journal of the Acoustical Society of America
Older adults are known to benefit from supportive context in order to compensate for age-related reductions in perceptual and cognitive processing, including when comprehending spoken language in adverse listening conditions. In the present study, we examine how younger and older adults benefit from two types of contextual support, predictability from sentence context and priming, when identifying target words in noise-vocoded sentences. In the first part of the experiment, benefit from context based on primarily semantic knowledge was evaluated by comparing the accuracy of identification of sentence-final target words that were either highly predictable or not predictable from the sentence context. In the second part of the experiment, benefit from priming was evaluated by comparing the accuracy of identification of target words when noise-vocoded sentences were either primed or not by the presentation of the sentence context without noise vocoding and with the target word replaced with white noise. Younger and older adults benefited from each type of supportive context, with the most benefit realized when both types were combined. Supportive context reduced the number of noise-vocoded bands needed for 50% word identification more for older adults than their younger counterparts.
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Posted by Callier Library on January 11, 2008
from the Journal of the Acoustical Society of America
Traditional accounts of speech perception generally hold that listeners use isolable acoustic “cues” to label phonemes. For syllable-final stops, duration of the preceding vocalic portion and formant transitions at syllable’s end have been considered the primary cues to voicing decisions. The current experiment tried to extend traditional accounts by asking two questions concerning voicing decisions by adults and children: (1) What weight is given to vocalic duration versus spectral structure, both at syllable’s end and across the syllable? (2) Does the naturalness of stimuli affect labeling? Adults and children (4, 6, and 8 years old) labeled synthetic stimuli that varied in vocalic duration and spectral structure, either at syllable’s end or earlier in the syllable. Results showed that all listeners weighted dynamic spectral structure, both at syllable’s end and earlier in the syllable, more than vocalic duration, and listeners performed with these synthetic stimuli as listeners had performed previously with natural stimuli. The conclusion for accounts of human speech perception is that rather than simply gathering acoustic cues and summing them to derive strings of phonemic segments, listeners are able to attend to global spectral structure, and use it to help recover explicitly phonetic structure.
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Posted by Callier Library on January 11, 2008
from the Journal of the Acoustical Society of America
There exists no clear understanding of the importance of spectral tilt for perception of stop consonants. It is hypothesized that spectral tilt may be particularly salient when formant patterns are ambiguous or degraded. Here, it is demonstrated that relative change in spectral tilt over time, not absolute tilt, significantly influences perception of /b/ vs /d/. Experiments consisted of burstless synthesized stimuli that varied in spectral tilt and onset frequency of the second formant. In Experiment 1, tilt of the consonant at voice onset was varied. In Experiment 2, tilt of the vowel steady state was varied. Results of these experiments were complementary and revealed a significant contribution of relative spectral tilt change only when formant information was ambiguous. Experiments 3 and 4 replicated Experiments 1 and 2 in an /aba/-/ada/ context. The additional tilt contrast provided by the initial vowel modestly enhanced effects. In Experiment 5, there was no effect for absolute tilt when consonant and vowel tilts were identical. Consistent with earlier studies demonstrating contrast between successive local spectral features, perceptual effects of gross spectral characteristics are likewise relative. These findings have implications for perception in nonlaboratory environments and for listeners with hearing impairment.
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Posted by Callier Library on January 11, 2008
from the Journal of the Acoustical Society of America
Cochlear-implant users perform far below normal-hearing subjects in background noise. Speech recognition with varying numbers of competing female, male, and child talkers was evaluated in normal-hearing subjects, cochlear-implant users, and normal-hearing subjects utilizing an eight-channel sine-carrier cochlear-implant simulation. Target sentences were spoken by a male. Normal-hearing subjects obtained considerably better speech reception thresholds than cochlear-implant subjects; the largest discrepancy was 24 dB with a female masker. Evaluation of one implant subject with normal hearing in the contralateral ear suggested that this difference is not caused by age-related disparities between the subject groups. Normal-hearing subjects showed a significant advantage with fewer competing talkers, obtaining release from masking with up to three talker maskers. Cochlear-implant and simulation subjects showed little such effect, although there was a substantial difference between the implant and simulation results with talker maskers. All three groups benefited from a voice pitch difference between target and masker, with the female talker providing significantly less masking than the male. Child talkers produced more masking than expected, given their fundamental frequency, syllabic rate, and temporal modulation characteristics. Neither a simulation nor testing in steady-state noise predicts the difficulties cochlear-implant users experience in real-life noisy situations.
Posted in Uncategorized | Tagged: cochlear implants, hearing, speech recognition | Leave a Comment »
Posted by Callier Library on January 11, 2008
from the Journal of the Acoustical Society of America
Studies comparing native and non-native listener performance on speech perception tasks can distinguish the roles of general auditory and language-independent processes from those involving prior knowledge of a given language. Previous experiments have demonstrated a performance disparity between native and non-native listeners on tasks involving sentence processing in noise. However, the effects of energetic and informational masking have not been explicitly distinguished. Here, English and Spanish listener groups identified keywords in English sentences in quiet and masked by either stationary noise or a competing utterance, conditions known to produce predominantly energetic and informational masking, respectively. In the stationary noise conditions, non-native talkers suffered more from increasing levels of noise for two of the three keywords scored. In the competing talker condition, the performance differential also increased with masker level. A computer model of energetic masking in the competing talker condition ruled out the possibility that the native advantage could be explained wholly by energetic masking. Both groups drew equal benefit from differences in mean F0 between target and masker, suggesting that processes which make use of this cue do not engage language-specific knowledge.
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Posted by Callier Library on January 11, 2008
from the Journal of the Acoustical Society of America
The existence of auditory cues such as intonation, rhythm, and pausing that facilitate end-of-utterance detection is by now well established. It has been argued repeatedly that speakers may also employ visual cues to indicate that they are at the end of their utterance. This raises at least two questions, which are addressed in the current paper. First, which modalities do speakers use for signalling finality and nonfinality, and second, how sensitive are observers to these signals. Our goal is to investigate the relative contribution of three different conditions to end-of-utterance detection: the two unimodal ones, vision only and audio only, and their bimodal combination. Speaker utterances were collected via a novel semicontrolled production experiment, in which participants provided lists of words in an interview setting. The data thus collected were used in two perception experiments, which systematically compared responses to unimodal (audio only and vision only) and bimodal (audio-visual) stimuli. Experiment I is a reaction time experiment, which revealed that humans are significantly quicker in end-of-utterance detection when confronted with bimodal or audio-only stimuli, than for vision-only stimuli. No significant differences in reaction times were found between the bimodal and audio-only condition, and therefore a second experiment was conducted. Experiment II is a classification experiment, and showed that participants perform significantly better in the bimodal condition than in the two unimodal ones. Both the first and the second experiment revealed interesting differences between speakers in the various conditions, which indicates that some speakers are more expressive in the visual and others in the auditory modality.
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Posted by Callier Library on January 11, 2008
from the Journal of the Acoustical Society of America
There has been a lack of objective data on the singing voice registers, particularly on the so called “whistle” register, occurring in the top part of the female pitch range, which is accessible only to some singers. This study offers unique strobolaryngoscopic and high-speed (7812.5 imagess) videokymographic data on the vocal fold behavior of an untrained female singer capable of producing three distinct voice qualities, i.e., the chest, head and whistle registers. The sound was documented spectrographically. The transition from chest to head register, accompanied by pitch jumps, occurred around tones B4-C#5 (500-550 Hz) and was found to be associated with a slight decrease in arytenoids adduction, resulting in decrease of the closed quotient. The register shifts from head to whistle, also accompanied by pitch jumps, occurred around tones E5-B5 (670-1000 Hz) without any noticeable changes in arytenoids adduction. Some evidence was found for the vocal tract influence on this transition. The mechanism of the vocal fold vibration in whistle register was found principally similar to that at lower registers: vibrations along the whole glottal length and vertical phase differences (indicated by sharp lateral peaks in videokymography) were seen on the vocal folds up to the highest tone G6 (1590 Hz).
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