The assessment of speech intelligibility in adults.
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Adult↗
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Results for “Speech Intelligibility”
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Evaluation of speech intelligibility for children with cleft lip and palate by means of automatic speech recognition.
OBJECTIVE: Cleft lip and palate (CLP) may cause functional limitations even after adequate surgical and non-surgical treatment, speech disorders being one of them. Interindividually, they vary a lot, showing typical articulation specifics such as nasal emission and shift of articulation and therefore a diminished intelligibility. Until now, an objective means to determine and quantify the intelligibility does not exist. METHOD: An automatic speech recognition system, a new method, was applied on recordings of a standard test to evaluate articulation disorders (psycholinguistic analysis of speech disorders of children PLAKSS) of 31 children at the age of 10.1+/-3.8 years. Two had an isolated cleft lip, 20 a unilateral cleft lip and palate, 4 a bilateral cleft lip and palate, and 5 an isolated cleft palate. The speech recognition system was trained with adults and children without speech disorders and adapted to the speech of children with CLP. In this study, the automatic speech evaluation focussed on the word accuracy which represents the percentage of correctly recognized words. Results were confronted to a perceptive evaluation of intelligibility that was performed by a panel of three experts. RESULTS: The automatic speech recognition yielded word accuracies between 1.2 and 75.8% (mean 48.0+/-19.6%). The word accuracy was lowest for children with isolated cleft palate (36.9+/-23.3) and highest for children with isolated cleft lip (72.8+/-2.9). For children with unilateral cleft lip and palate it was 48.0+/-18.6 and for children with bilateral cleft lip and palate 49.3+/-9.4. The automatic evaluation complied with the experts' subjective evaluation of intelligibility (p<0.01). The multi-rater kappa of the experts alone differed only slightly from the multi-rater kappa of experts and recognizer. CONCLUSION: Automatic speech recognition may serve as a good means to objectify and quantify global speech outcome of children with cleft lip and palate.
Adolescent↗
Effects of gender on listeners' judgments of speech intelligibility.
Effects of gender on listeners' judgments of intelligibility were investigated. Subjects (15 women; 15 men) provided magnitude-estimation scaling responses and over-all impression of the intelligibility of a male and female speaker's comparable versions of audiotaped speech samples varying systematically in terms of the number of phonemes produced correctly. There was no significant difference between male and female subjects' magnitude-estimation scaling responses; however, their over-all impressions of the intelligibility of the speakers tended to differ. Women indicated that the male speaker was more understandable, and men indicated that the female speaker was more understandable. Magnitude-estimation scaling may provide an objective means for evaluating a speaker's intelligibility. It appears to transcend gender-biases associated with judgments of speech intelligibility.
Adult↗
Sound-direction identification, interaural time delay discrimination, and speech intelligibility advantages in noise for a bilateral cochlear implant user.
OBJECTIVES: To characterize some of the benefits available from using two cochlear implants compared with just one, sound-direction identification (ID) abilities, sensitivity to interaural time delays (ITDs) and speech intelligibility in noise were measured for a bilateral multi-channel cochlear implant user. METHODS: Sound-direction ID in the horizontal plane was tested with a bilateral cochlear implant user. The subject was tested both unilaterally and bilaterally using two independent behind-the-ear ESPRIT (Cochlear Ltd.) processors, as well as bilaterally using custom research processors. Pink noise bursts were presented using an 11-loudspeaker array spanning the subject's frontal 180 degrees arc in an anechoic room. After each burst, the subject was asked to identify which loudspeaker had produced the sound. No explicit training, and no feedback were given. Presentation levels were nominally at 70 dB SPL, except for a repeat experiment using the clinical devices where the presentation levels were reduced to 60 dB SPL to avoid activation of the devices' automatic gain control (AGC) circuits. Overall presentation levels were randomly varied by +/- 3 dB. For the research processor, a "low-update-rate" and a "high-update-rate" strategy were tested. Direct measurements of ITD just noticeable differences (JNDs) were made using a 3 AFC paradigm targeting 70% correct performance on the psychometric function. Stimuli included simple, low-rate electrical pulse trains as well as high-rate pulse trains modulated at 100 Hz. Speech data comparing monaural and binaural performance in noise were also collected with both low, and high update-rate strategies on the research processors. Open-set sentences were presented from directly in front of the subject and competing multi-talker babble noise was presented from the same loudspeaker, or from a loudspeaker placed 90 degrees to the left or right of the subject. RESULTS: For the sound-direction ID task, monaural performance using the clinical devices showed large mean absolute errors of 81 degrees and 73 degrees, with standard deviations (averaged across all 11 loud-speakers) of 10 degrees and 17 degrees, for left and right ears, respectively. Fore bilateral device use at a presentation level of 70 dB SPL, the mean error improved to about 16 degrees with an average standard deviation of 18 degrees. When the presentation level was decreased to 60 dB SPL to avoid activation of the automatic gain control (AGC) circuits in the clinical processors, the mean response error improved further to 8 degrees with a standard deviation of 13 degrees. Further tests with the custom research processors, which had a higher stimulation rate and did not include AGCs, showed comparable response errors: around 8 or 9 degrees and a standard deviation of about 11 degrees for both update rates. The best ITD JNDs measured for this subject were between 350 to 400 microsec for simple low-rate pulse trains. Speech results showed a substantial headshadow advantage for bilateral device use when speech and noise were spatially separated, but little evidence of binaural unmasking. For spatially coincident speech and noise, listening with both ears showed similar results to listening with either side alone when loudness summation was compensated for. No significant differences were observed between binaural results for high and low update-rates in any test configuration. Only for monaural listening in one test configuration did the high rate show a small significant improvement over the low rate. CONCLUSION: Results show that even if interaural time delay cues are not well coded or perceived, bilateral implants can offer important advantages, both for speech in noise as well as for sound-direction identification.
Adult↗
[Thresholds of the minimal perceptible differences in coupled sounds and speech intelligibility in hard of hearing schoolchildren].
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Adolescent↗
The use of strategies to increase speech intelligibility in cerebral palsy: an experimental evaluation.
The effects of strategies on the intelligibility of cerebral-palsied speech were experimentally evaluated. Listeners were asked to identify words in sentences spoken by subjects whose dysarthria was rated to be either moderate or severe. Results indicated that strategies increased intelligibility and that different strategies were appropriate at different levels of severity. Use of initial letter cueing achieved the greatest gains for the more severely impaired speakers but, for the less severely impaired, the gains achieved by providing visual cues were the same as those achieved by letter cueing and could not be improved upon by repetition. Listeners' experience of dysarthric speech and the redundancy of the test sentences were also manipulated. Previous experience did not influence recognition and redundancy only appeared to have an influence at higher levels of intelligibility. The role of strategies in improving intelligibility is discussed. The results suggest that many speakers will be unable to use simple strategies to improve intelligibility to levels that may be needed for adequate information transfer.
Adolescent↗
A comparison of speech intelligibility between esophageal and normal speakers via three modes of presentation.
This study compared intelligibility scores obtained for sentences read by good-to-superior esophageal speakers with scores obtained for sentences read by normal speakers via three modes of presentation: visual, auditory and auditory-visual combined. Statistical analysis showed significant differences between intelligibility scores for esophageal speakers and for normal speakers in the auditory and in the combined conditions. No significant difference was found between the scores for the two groups in the visual condition. Further analysis showed that the esophageal speakers' intelligibility scores improved significantly from the auditory to the combined auditory-visual condition where they most closely approximated, but never equaled, the highest intelligibility scores for normal speakers. Implications of the findings for rehabilitation of esophageal speakers are discussed.
Audiovisual Aids↗
[Otoacoustic emissions, auditory evoked potentials, pure tone thresholds and speech intelligibility in cases of auditory neuropathy].
The combined findings of "normal evoked otoacoustic emissions (EOAE) and absent or markedly disturbed auditory evoked potentials from the brainstem and/or cortex" has been named auditory neuropathy in the English literature. The pure tone thresholds in these patients range from mild to severe loss. The loss of speech comprehension is out of proportion in comparison to the pure tone threshold elevation. This combination of findings suggests that cochlear function and in particular outer hair cell function, is normal in these patients but also suggests that the inner hair cell / VIII nerve functional unit is abnormal. Disruption in neural synchrony has previously been postulated as a reasonable explanation for the absent auditory brainstem response while otoacoustic emissions are preserved. Because the long-latency auditory evoked potentials, not having the stringent synchrony requirements of the ABR, may also be missing, the term synchrony - disruption may be somewhat misleading. The literature about auditory neuropathy is reviewed here: We now know that a set of salient features distinguishes these patients from the majority of patients with sensorineural hearing loss or other described syndromes. The symptoms defining auditory neuropathy are mild, moderate or severe elevation of auditory thresholds to pure tone stimuli by air and bone conduction, absent to severely abnormal ABRs to high level stimuli, present otoacoustic emissions (that do not suppress with contralateral noise), word recognition ability poorer than expected from the pure tone hearing loss configuration (in cases with mild to moderate hearing threshold elevation) and absent acoustic reflexes to both ipsilateral and contralateral tones. The entire set of findings, consistently seen in these patients, supports the importance of the crosscheck principle in diagnostic evaluation especially in children with delayed and/or impaired language acquisition. It is of ponderous importance that this disorder is not being confused with sensory hearing loss.
Adult↗
Speech intelligibility after partial glossectomy in children with Down's syndrome.
Twenty-three children with Down's syndrome, aged between 3.7 and 17.5 years, underwent partial glossectomy for improvement of cosmetic appearance. Improved speech was also expected. Preoperative and postoperative audiotaped samples of spoken words and connected speech on a standardized articulation test were rated by three lay and three expert listeners on a five-point intelligibility scale. Five subjects were eliminated from both tasks and another four from connected-speech testing because of inability to complete the experimental tasks. Statistical analyses of ratings for words in 18 subjects and connected speech in 14 of them revealed no significant difference in acoustic speech intelligibility preoperatively and postoperatively. The findings suggest that a wedge-excision partial glossectomy in children with Down's syndrome does not result in significant improvement in acoustic speech intelligibility; in some patients, however, there may be an aesthetic improvement during speech.
Adolescent↗
Speech perception and speech intelligibility in children with multichannel cochlear implants.
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Age of Onset↗
Factors associated with speech intelligibility in children with cochlear implants.
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Case-Control Studies↗
Spectro-temporal modulation transfer functions and speech intelligibility.
Detection thresholds for spectral and temporal modulations are measured using broadband spectra with sinusoidally rippled profiles that drift up or down the log-frequency axis at constant velocities. Spectro-temporal modulation transfer functions (MTFs) are derived as a function of ripple peak density (omega cycles/octave) and drifting velocity (omega Hz). The MTFs exhibit a low-pass function with respect to both dimensions, with 50% bandwidths of about 16 Hz and 2 cycles/octave. The data replicate (as special cases) previously measured purely temporal MTFs (omega = 0) [Viemeister, J. Acoust. Soc. Am. 66, 1364-1380 (1979)] and purely spectral MTFs (omega = 0) [Green, in Auditory Frequency Selectivity (Plenum, Cambridge, 1986), pp. 351-359]. A computational auditory model is presented that exhibits spectro-temporal MTFs consistent with the salient trends in the data. The model is used to demonstrate the potential relevance of these MTFs to the assessment of speech intelligibility in noise and reverberant conditions.
Auditory Threshold↗
[Influence of vocal effort on the physical characteristics of the voice and on speech intelligibility].
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Hearing↗
[Speech intelligibility and psychosocial adaptation in various voice rehabilitation methods following laryngectomy].
Intelligibility and psychosocial adjustment are measured by the PLTT (Post-Laryngectomy-Telephone-Test) and a newly developed questionnaire (FPAL). 110 male patients with total or partial laryngectomies are tested. Three different groups are compared with each other: laryngectomees with voice prostheses, laryngectomees with oesophageal voice or artificial larynx, and patients with partial laryngectomies. As was to be expected, intelligibility (single words and sentences) was best in patients with partial laryngectomies. The intelligibility of the laryngectomees with voice prostheses is significantly higher than the intelligibility of patients with oesophageal voice or artificial larynx. There was no difference between the groups with regard to the subjective assessment of intelligibility in relation to various communication partners. Partial laryngectomies have the lowest negative impact on the social and psychological situation of the patients. Laryngectomees, however, are more lonely, indicate more psychological stress in social interactions, and have a less positive evaluation of their life. Statistical analyses reveal no difference in psychosocial adjustment between laryngectomees with voice prostheses, oesophageal voice and artificial larynges.
Adaptation, Psychological↗
Spectral restoration of speech: intelligibility is increased by inserting noise in spectral gaps.
In order to function effectively as a means of communication, speech must be intelligible under the noisy conditions encountered in everyday life. Two types of perceptual synthesis have been reported that can reduce or cancel the effects of masking by extraneous sounds: Phonemic restoration can enhance intelligibility when segments are replaced or masked by noise, and contralateral induction can prevent mislateralization by effectively restoring speech masked at one ear when it is heard in the other. The present study reports a third type of perceptual synthesis induced by noise: enhancement of intelligibility produced by adding noise to spectral gaps. In most of the experiments, the speech stimuli consisted of two widely separated narrow bands of speech (center frequencies of 370 and 6,000 Hz, each band having high-pass and low-pass slopes of 115 dB/octave meeting at the center frequency). These very narrow bands effectively reduced the available information to frequency-limited patterns of amplitude fluctuation lacking information concerning formant structure and frequency transitions. When stochastic noise was introduced into the gap separating the two speech bands, intelligibility increased for "everyday" sentences, for sentences that varied in the transitional probability of keywords, and for monosyllabic word lists. Effects produced by systematically varying noise amplitude and noise bandwidth are reported, and the implications of some of the novel effects observed are discussed.
Adult↗
Spectral feature enhancement for people with sensorineural hearing impairment: effects on speech intelligibility and quality.
People with sensorineural hearing loss often have difficulty understanding speech in background noise at speech-to-noise ratios (0 to +6 dB) for which normally hearing people have little difficulty. Spectral analysis of speech in noise at these ratios typically shows that the major spectral prominences in the speech (formants) are well represented, but the spectral valleys between the formants are filled with noise. Hearing impaired people have a reduced ability to pick out the spectral prominences, and are more affected by the noise filling in the valleys, partly because of their reduced frequency selectivity. This paper describes a 16-channel bandpass filter bank, implemented in analog electronics, that attempts to enhance spectral features of speech in noise to improve intelligibility for the hearing impaired. Each channel generates an 'activity function' that is proportional to the magnitude of the signal envelope in that channel, averaged over a short period of time. A positively weighted activity function from the nth channel is combined with negatively weighted functions from channels n-2, n-1, n+1, and n+2, giving a correction signal used to control the gain of the bandpass signal in the nth channel. Recombining the bandpass signals results in an enhancement of spectral features of the speech in noise. Two different experiments are described here, one using the activity function as described, and the other using a non-linear transform of the activity function. In both experiments, several different weighting patterns were used in calculating the correction signal. The intelligibility of speech in noise processed by the system was measured for subjects with moderate sensorineural hearing loss. In both experiments, no improvement in intelligibility was found. However, subjective ratings of the stimuli used in Experiment 2 indicated that some subjects judged the processed stimuli to have both higher quality and higher intelligibility than unprocessed stimuli.
Electronics↗
Speech intelligibility of deaf speakers and distinctive feature usage.
Speech samples (41 CNC monosyllables) of 22 deaf children were analyzed using two distinctive-feature systems, one acoustic and one physiologic. Moderate to high correlations between intelligibility scores by listener judges vs correct feature usage were obtained for positive as well as negative features of both systems. Further, higher correlations between percent-correct feature usage scores vs listener intelligibility scores were observed for phonemes in the initial vs final position-in-work regardless of listener-judge experience, feature system, or presentation mode. These findings suggest that either acoustic or physiologic feature analysis can be employed in describing the articulation of deaf talkers. In general, either of these feature systems also predicts with fair to good accuracy the intelligibility of deaf speakers as judged by either experienced or inexperienced listeners. In view of the appreciably higher correlations obtained between feature use and intelligibility scores in initial compared to final position-in-word, however, caution should be exercised with either of the feature systems studied in predicting the intelligibility of a deaf speaker's final phoneme.
Adolescent↗
Speaker-listener familiarity: parents as judges of delayed speech intelligibility.
It has been frequently proposed that one source of bias in intelligibility judgments is whether the judge knows the subject personally. This study attempted to describe this bias using 4 speech-delayed children (aged 4 and 7 years) with normal hearing and no significant language delay. They were audiotaped at four points during therapy over a 12-18 month period using imitation of single words derived from the Assessment of the Intelligibility of Dysarthric Speech. Parents and a group of unfamiliar adult couples served as judges. Results indicated that mothers were significantly better than all other listeners (including fathers) at identifying the words being spoken. An interaction between listener type and subject age class was also observed with the maternal advantage being much less apparent with the 2 older subjects. Results are discussed relative to the possible source of the mothers' superior performance.
Adult↗