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At least 19 recordsLinked to original sources
PubMed1991

The effects of digital quantization error on speech intelligibility and perceived speech quality.

The effects of digital quantization error upon speech intelligibility and perceived speech quality, for normally hearing subjects, were investigated for digitized speech processed to simulate 6-, 8-, 10-, 12-, 14-, and 16-bit integer conversion and 2-, 3-, 4-, 5-, 6-, and 7-bit floating-point conversion. For the integer data, there were no significant differences in speech intelligibility for 8- to 16-bit conversion. Only 6-bit integer conversion at 55 dB SPL resulted in a significant degradation in speech intelligibility. For the floating-point data, there were no significant differences in speech intelligibility for 2- to 7-bit floating-point conversion. However, results of the perceived quality experiment appeared to be more sensitive to differences among the various conditions. Speech processed using 12-, 14-, and 16-bit integer conversion was judged to be superior to speech processed using the 6-, 8-, and 10-bit integer conditions. Speech processed using 5-, 6-, and 7-bit floating-point conversion was judged to be superior to speech processed using 2-, 3-, and 4-bit floating-point conversion.

Acoustics↗
PubMed1986

Consonant influences on vowel duration as a function of speech intelligibility for hearing-impaired individuals.

The purpose of this investigation was to study the effects of consonant environment on vowel duration for normally hearing males, hearing-impaired males with intelligible speech, and hearing-impaired males with semi-intelligible speech. The results indicated that the normally hearing and intelligible hearing-impaired speakers exhibited similar trends with respect to consonant influence on vowel duration; i.e., vowels were longer in duration, in a voiced environment as compared with a voiceless, and in a fricative environment as compared with a plosive. The semi-intelligible hearing-impaired speakers, however, failed to demonstrate a consonant effect on vowel duration, and produced the vowels with significantly longer durations when compared with the other two groups of speakers. These data provide information regarding temporal conditions which may contribute to the decreased intelligibility of hearing-impaired persons.

Acoustic Stimulation↗
PubMedDate not supplied

Auditory temporal acuity of the hearing impaired and its relationship to speech intelligibility.

Auditory temporal acuity (deltat) was measured in 42 hearing-impaired subjects to investigate the hypothesis that it would facilitate the production of intelligible speech. The measure divided the test population into two subgroups with mean speech intelligibility measures of 77.7 and 52.6%, respectively. These results are discussed along with implications relating to hearing loss and the slope of audiogram.

Adolescent↗
PubMed1979

Speech intelligibility in and speech interference levels of traffic noise in hearing-impaired and normal listeners.

Speech intelligibility (phonetically balanced monosyllables = PB words) in traffic-like noise (random noise) as well as the speech interference levels (75% intelligibility) of this noise were investigated in three common listening situations, two indoors and one outdoors. A total of 279 persons were examined; 56 had normal hearing, 90 a presbycusic-type hearing loss, 95 noise-induced hearing loss, and 38 conductive hearing loss. In the indoor situation the hearing-impaired groups mainly retained their intelligibility in 40 dBA. Lowering of the noise level to less than 40 dBA resulted in only a minor, mostly insignificant improvement in speech intelligibility. Normal-hearing listeners maintained good speech intelligibility in the outdoor listening situation with noise levels up to 60 dBA, without lip-reading. For hearing-impaired groups, representing more than 1/2 million (8% of the population) people in Sweden, with hearing loss due to age and/or noise, the noise level outdoors must be lowered to 45 dBA in order to achieve good speech intelligibility at 1 m, without lip-reading.

Adolescent↗
PubMed1988

The effects of different frequency responses on sound quality judgments and speech intelligibility.

Four speech programs and two music programs were reproduced using five different frequency responses: one flat and the others combinations of reductions at lower frequencies and/or increases at higher frequencies. Twelve hearing impaired (HI) and 8 normal hearing (NH) subjects listened monaurally to the reproductions at comfortable listening level and judged the sound quality on seven perceptual scales and a scale for total impression. Speech intelligibility was measured for phonetically balanced (PB) word lists and for sentences in noise. Significant differences among the reproductions appeared in practically all scales. The most preferred system was characterized by a flat response at lower frequencies and a 6 dB/octave increase thereafter. There were certain differences between the NH and HI listeners in the judgments of the other systems. The intelligibility of PB word lists did not differ among the systems, and the S/N threshold for the sentences in noise only distinguished the flat response as worse than all others for the HI listeners. There was little correspondence between intelligibility measures and sound quality measures. The latter provided more information and distinctions among systems.

Adult↗
PubMed1989

The effect of stapedectomy on speech intelligibility in noise.

Speech intelligibility in noise was tested pre- and postoperatively after 27 stapedectomy cases and 10 cases of reexploration after previous stapes surgery. We did not find a postoperative threshold shift (signal-to-noise ratio) for the intelligibility of sentences presented in noise. This finding corresponds well with the absence of postoperative high-frequency sensorineural loss in these patients. Using two types of prostheses we found a significant amelioration of speech intelligibility in quiet for the Schuknecht minihole prosthesis as compared to the House wire loop.

Adult↗
PubMed1986

Speech intelligibility studies in classrooms.

Speech intelligibility tests and acoustical measurements were made in ten occupied classrooms. Octave-band measurements of background noise levels, early decay times, and reverberation times, as well as various early/late sound ratios, and the center time were obtained. Various octave-band useful/detrimental ratios were calculated along with the speech transmission index. The interrelationships of these measures were considered to evaluate which were most appropriate in classrooms, and the best predictors of speech intelligibility scores were identified. From these results ideal design goals for acoustical conditions for classrooms were determined either in terms of the 50-ms useful/detrimental ratios or from combinations of the reverberation time and background noise level.

Adolescent↗
PubMed1982

Frequency selectivity and speech intelligibility in noise.

Poor speech intelligibility in noise is a major problem for persons afflicted by a sensorineural hearing loss, and this problem is generally not alleviated by a hearing aid. For a typical hearing loss the effective signal-to-noise ratio is degraded by 10 - 15 dB, predominantly due to impoverished frequency selectivity. The critical ratio averaged over speech frequencies is a convenient measure of this component of the auditory handicap. An attempt to improve speech intelligibility in noise through dichotic combfiltering was not successful.

Audiometry, Pure-Tone↗
PubMed1982

Speech intelligibility in noise: effects of fluency and hearing protector type.

This research investigated the effect of car protectors on the intelligibility of speech in noise. Listeners with normal hearing, high-frequency, and flat loss were tested. Half the subjects in each group were fluent in English and half-poorly conversant. Taped lists of 25 words were presented free field under conditions defined by the speech-to-noise ratio, spectrum of noise background, and presence of ear protection. The results showed that intelligibility decreased with speech-to-noise ratio and was poorer in crowd noise than in white noise. The protector had no effect for the normal listener, but caused a substantial decrement in those with impairment. In all groups nonfluency contributed an additional loss of 10% to 20%. Significant differences in performance were noted for different muff and plug types.

Adult↗
PubMed1990

Evaluation of adult aphasics with the Pediatric Speech Intelligibility test.

Results of conventional adult speech audiometry may be compromised by the presence of speech/language disorders, such as aphasia. The purpose of this project was to determine the efficacy of the speech intelligibility materials and techniques developed for young children in evaluating central auditory function in aphasic adults. Eight adult aphasics were evaluated with the Pediatric Speech Intelligibility (PSI) test, a picture-pointing approach that was carefully developed to be relatively insensitive to linguistic-cognitive skills and relatively sensitive to auditory-perceptual function. Results on message-to-competition ratio (MCR) functions or performance-intensity (PI) functions were abnormal in all subjects. Most subjects served as their own controls, showing normal performance on one ear coupled with abnormal performance on the other ear. The patterns of abnormalities were consistent with the patterns seen (1) on conventional speech audiometry in brain-lesioned adults without aphasia and (2) on the PSI test in brain-lesioned children without aphasia. An exception to this general observation was an atypical pattern of abnormality on PI-function testing in the subgroup of nonfluent aphasics. The nonfluent subjects showed substantially poorer word-max scores than sentence-max scores, a pattern seen previously in only one other patient group, namely young children with recurrent otitis media. The unusually depressed word-max abnormality was not meaningfully related to clinical diagnostic data regarding the degree of hearing loss and the location and severity of the lesions or to experimental data regarding the integrity of phonologic processing abilities. The observations of ear-specific and condition-specific abnormalities suggest that the linguistically- and cognitively-simplified PSI test may be useful in the evaluation of auditory-specific deficits in the aphasic adult.

Adult↗
PubMed1981

Evaluation of binaural hearing aids in children using localization and speech intelligibility tasks.

Because of an assumed relationship between localization and speech intelligibility in noise it has been suggested that a localization test provides a suitable measure for the evaluation of binaural aids in everyday situations. The present study shows a significant correlation (a) between binaural advantage in a localization task and the binaural advantage in speech intelligibility in noise task, and (b) between binaural advantage in judgement of separation of speech and noise and binaural advantage in a speech intelligibility in noise task. However, neither relationship was strong enough for accurate individual prediction of binaural advantages in speech intelligibility. Possible reasons for this are discussed, and the lines that further research might follow are suggested.

Adolescent↗
PubMedDate not supplied

Development of speech intelligibility in children with recurrent otitis media.

This study defined developmental functions for Pediatric Speech Intelligibility word and sentence materials presented in quiet and in competition for 25 normal children and 25 children with recurrent otitis media. Ages ranged from 24 to 56 mos. In normal children, developmental functions for Pediatric Speech Intelligibility speech materials showed earlier development of performance (1) in quiet than in competition and (2) for words than for sentences (competing condition). In children with otitis media, developmental functions were normal for both words and sentences in quiet and for sentences in competition. However, developmental functions were grossly abnormal for words in competition.

Child, Preschool↗
PubMed1991

Effects of a single reflection with varied horizontal angle and time delay on speech intelligibility.

Previously, almost all physical measures for estimating speech intelligibility in a room have been derived from only temporal-monaural criteria. This paper shows that speech intelligibility for a sound field with a single reflection depends not only on the temporal-monaural factor but also on the spatial-binaural factor of the sound field. Articulation tests for sound fields simulated with a single reflection of delay time delta t1 after the direct sound were conducted changing the horizontal incident angle xi of the reflection. Remarkable findings are as followings: (1) speech intelligibility (SI) decreases with increasing delay time delta t1, (2) SI increases when xi approaches 90 degrees; the horizontal angle of the reflection causes a significant effect on SI, and (3) the analysis of variance for articulation test scores clearly demonstrated that the effects of both delta t1 and xi on SI are fully independent. Concerning result (2), if listeners get a spatial separation of signals at the two ears, then the listener's capability for speech perception is assumed to be improved due to "adding" further information to the temporal pattern recognition.

Acoustics↗
PubMed1982

Amplification bandwidth and speech intelligibility for two listeners with sensorineural hearing loss.

The intelligibility of speech as a function of its bandwidth was measured for two listeners with similar, moderately severe sensorineural hearing losses. The shape of the speech spectrum was adjusted to approximate the individual listener's contour of most comfortable listening levels (MCLs) and the overall level was set so that the levels in each band were below (-7 dB), near to (+3 dB), or above (+13 or +18 dB) the MCLs. At each level, nine pairings of three low-frequency and three high-frequency cutoffs (266, 375 and 530 Hz; 3,000, 4,242 and 6,000 Hz) were used. These conditions were achieved by passing the speech through a Limiting Master Hearing Aid (LMHA) which allows independent control of gain and maximum output in each of nine, half-octave bands. It was found that the wider the bandwidth, the higher the score, and the greater the amount of speech energy above threshold, the higher the score. Listeners' ability to understand the test material, after adjustment for listener differences, was correlated (0.7 and 0.8) with the articulation index.

Adult↗
PubMed1984

The use of single-channel compression for the improvement of speech intelligibility.

In this study, speech perception with commercially available linear and single-channel input- and output-dependent compression aids was investigated. Although compression has been introduced as a method of limiting the maximum output, theoretically expectations have been raised that a gain in speech intelligibility could also be obtained by a better use of the reduced dynamic range of the patient. It turned out that there was no significant difference in speech reception thresholds obtained both in quiet and in noise between the aids used for a group of 12 hearing-impaired hearing-aid users as a whole, or for different subgroups thereof.

Adult↗
PubMed1990

Impairment of speech intelligibility in men with amyotrophic lateral sclerosis.

Speech intelligibility was studied in a group of 25 male patients with amyotrophic lateral sclerosis (ALS). The object of the study was to determine the phonetic impairments underlying the speech intelligibility deficits that frequently accompany ALS. Analyses with a word intelligibility test indicated that the most disrupted phonetic features involved phonatory (voicing contrast) function, velopharyngeal valving, place and manner of articulation for lingual consonants, and regulation of tongue height for vowels. The mean error proportion for the five most severely affected features correlated highly (0.97) with the intelligibility score (percent correct). The phonetic feature analyses are one index of bulbar muscle impairment in amyotrophic lateral sclerosis and also may help to direct the speech management in these individuals.

Adult↗
PubMed1986

Age at fitting of hearing aids and speech intelligibility.

This paper reports on the effect of age at fitting of hearing aids on subsequent achievements in speech intelligibility among hearing-impaired children. Four groups of hearing-impaired children were included in this investigation. Group A (n = 32) started using hearing aids in their first 6 months of life; Group B (n = 32) in their second 6 months of life; Group C (n = 38) in their second year of life and Group D (n = 51) in their third year of life. The children in each group were matched with regard to age, sex, age at onset of deafness, degree of hearing loss and educational establishment attended. The speech intelligibility of each child was rated by his/her class teacher on a 7-point scale. It was found that the speech intelligibility of the children in Group A was significantly superior to the speech intelligibility of the children in the other three groups. All other differences in speech intelligibility obtained between groups (Group B v. Group C v. Group D) were small and none proved to be statistically significant.

Age Factors↗