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At least 19 recordsLinked to original sources
PubMed1999

On the combined effects of signal-to-noise ratio and room acoustics on speech intelligibility.

Speech intelligibility in rooms is influenced by room acoustics effects and by the signal-to-noise ratio (S/N) of the speech and ambient noise. Several measures such as useful-to-detrimental sound ratios and the speech transmission index predict the combined effects of both types of factors. These measures were evaluated relative to speech intelligibility test results obtained in simulated sound fields. The use of simulated sound fields made it possible to create the full range of combinations of room acoustics and S/N effects likely to be found in rooms for speech. The S/N aspect is shown to be much more important than room acoustics effects and new broadband useful-to-detrimental ratios were validated. Useful-to-detrimental ratios, speech transmission index measures, and values of the articulation loss for consonants were all reasonably accurate predictors of speech intelligibility. Further improvements to these combined measures are suggested.

Environment↗
PubMed2003

Judgments of speech intelligibility and speech annoyance by mothers of children who are deaf or hard of hearing.

14 mothers of children who were deaf or hard of hearing provided magnitude estimation scaling responses for the speech intelligibility and speech annoyance of narrative speech samples produced by children who were deaf or hard of hearing. Analysis indicated that listeners scaled intelligibility and annoyance the same. As samples became more difficult to understand, they also became more annoying to these listeners. Implications for further research are discussed.

Adult↗
PubMed1999

Magnitude estimation scaling judgments of speech intelligibility and speech acceptability.

20 female students in speech-language pathology provided magnitude estimation scaling responses for the speech intelligibility and acceptability of audio-taped speech samples varying systematically the number of consonant sounds produced correctly. Analysis indicated no significant over-all differences between listeners' judgments of intelligibility and acceptability; however, listeners tended to judge samples with fewer than 50% of the consonants correct as more acceptable than intelligible, and they judged samples with more than 50% consonants correct as less acceptable than intelligible.

Adult↗
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↗
PubMed2000

Sophisticated and naïve listeners' magnitude estimation scaling judgments of speech intelligibility and speech annoyance.

15 women with formal training in speech and hearing sciences and 15 women with no formal training provided magnitude estimation scaling responses for the intelligibility and annoyance of audiotaped speech samples. Analysis indicated that both groups scaled intelligibility and annoyance the same. As samples became more unintelligible, they also became more annoying.

Acoustic Stimulation↗
PubMed1998

Speech intelligibility assessment in a helium environment. II. The speech intelligibility index.

The Speech Intelligibility Index (SII) was measured for Navy divers participating in two saturation deep dives and for a group of nondivers to test different communication systems and their components. These SIIs were validated using the Speech Perception in Noise (SPIN) test and the Griffiths version of the Modified Rhyme Test (GMRT). Our goal was to determine if either of these assessments was sensitive enough to provide an objective measure of speech intelligibility when speech was processed through different helmets and helium speech unscramblers (HSUs). Results indicated that SII values and percent intelligibility decreased incrementally as background noise level increased. SIIs were very reliable across the different groups of subjects indicating that the SII was a strong measurement for predicting speech intelligibility to compare linear system components such as helmets. The SII was not useful in measuring intelligibility through nonlinear devices such as HSUs. The speech intelligibility scores on the GMRT and SPIN tests were useful when the system component being compared had a large measurable difference, such as in helmet type. However, when the differences were more subtle, such as differences in HSUs, neither the SPIN nor the GMRT appeared sensitive enough to make such distinctions. These results have theoretical as well as practical value for measuring the quality and intelligibility of helium speech enhancement systems.

Adolescent↗
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↗
PubMed2000

Reverberation time and maximum background-noise level for classrooms from a comparative study of speech intelligibility metrics.

Speech intelligibility metrics that take into account sound reflections in the room and the background noise have been compared, assuming diffuse sound field. Under this assumption, sound decays exponentially with a decay constant inversely proportional to reverberation time. Analytical formulas were obtained for each speech intelligibility metric providing a common basis for comparison. These formulas were applied to three sizes of rectangular classrooms. The sound source was the human voice without amplification, and background noise was taken into account by a noise-to-signal ratio. Correlations between the metrics and speech intelligibility are presented and applied to the classrooms under study. Relationships between some speech intelligibility metrics were also established. For each noise-to-signal ratio, the value of each speech intelligibility metric is maximized for a specific reverberation time. For quiet classrooms, the reverberation time that maximizes these speech intelligibility metrics is between 0.1 and 0.3 s. Speech intelligibility of 100% is possible with reverberation times up to 0.4-0.5 s and this is the recommended range. The study suggests "ideal" and "acceptable" maximum background-noise level for classrooms of 25 and 20 dB, respectively, below the voice level at 1 m in front of the talker.

Humans↗
PubMed2001

Speech intelligibility after glossectomy and speech rehabilitation.

BACKGROUND: Oral tumor resections cause articulation deficiencies, depending on the site, extent of resection, type of reconstruction, and tongue stump mobility. OBJECTIVES: To evaluate the speech intelligibility of patients undergoing total, subtotal, or partial glossectomy, before and after speech therapy. PATIENTS AND METHODS: Twenty-seven patients (24 men and 3 women), aged 34 to 77 years (mean age, 56.5 years), underwent glossectomy. Tumor stages were T1 in 3 patients, T2 in 4, T3 in 8, T4 in 11, and TX in 1; node stages, N0 in 15 patients, N1 in 5, N2a-c in 6, and N3 in 1. No patient had metastases (M0). Patients were divided into 3 groups by extent of tongue resection, ie, total (group 1; n = 6), subtotal (group 2; n = 9), and partial (group 3; n = 12). Different phonological tasks were recorded and analyzed by 3 experienced judges, including sustained 7 oral vowels, vowel in a syllable, and the sequence vowel-consonant-vowel (VCV). The intelligibility of spontaneous speech (sequence story) was scored from 1 to 4 in consensus. All patients underwent a therapeutic program to activate articulatory adaptations, compensations, and maximization of the remaining structures for 3 to 6 months. The tasks were recorded after speech therapy. To compare mean changes, analyses of variance and Wilcoxon tests were used. RESULTS: Patients of groups 1 and 2 significantly improved their speech intelligibility (P<.05). Group 1 improved vowels, VCV, and spontaneous speech; group 2, syllable, VCV, and spontaneous speech. Group 3 demonstrated better intelligibility in the pretherapy phase, but the improvement after therapy was not significant. CONCLUSIONS: Speech therapy was effective in improving speech intelligibility of patients undergoing glossectomy, even after major resection. Different pretherapy ability between groups was seen, with improvement of speech intelligibility in groups 1 and 2. The improvement of speech intelligibility in group 3 was not statistically significant, possibly because of the small and heterogeneous sample.

Adult↗
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↗
PubMed1994

Effects of temporal smearing on temporal resolution, frequency selectivity, and speech intelligibility.

Envelopes of speech were smeared in 23 parallel frequency channels. The smeared speech was presented to normal-hearing listeners, and the effects of different smearing magnitudes on speech intelligibility were measured by obtaining speech recognition scores. It was demonstrated theoretically and experimentally that the system consisting of the computer smearing and the auditory system had reduced temporal resolution but nearly normal frequency resolution. Speech intelligibility of the processed vowel-consonant nonsense syllables was tested for low- and high-pass filter conditions. The overall speech recognition scores as well as the recognition scores of the consonants grouped according to articulatory features were analyzed. The results indicated that smearing with a narrow temporal window did not degrade speech. The larger equivalent rectangular durations (ERDs) of the resultant temporal window (RTW) of the combined system (temporal smearing plus auditory system) produced a small but significant reduction in speech intelligibility for the low-pass filter condition. Scores for the RTWs > 16 ms were significantly different from the score for the 7.7-ms RTW for the high-pass filter condition, but this effect was small and did not differ across articulatory features.

Adolescent↗
PubMed2006

Callsign Acquisition Test (CAT): speech intelligibility in noise.

OBJECTIVE: The study was designed to assess the effects of noise on the intelligibility of speech elements used in the Callsign Acquisition Test (CAT), developed by the U.S. Army Research Laboratory. The CAT consists of 126 test items, or callsigns, each of which is made up of a two-syllable word selected from the 18-item military alphabet (Alpha-Zulu) followed by a one-syllable number (all numbers from 1 to 8, excluding 7). DESIGN: The CAT items were mixed with one of three different types of background noises (pink noise, white noise, and multitalker babble) and presented to 18 listeners. Speech-to-noise ratio for all three noises and the overall level of pink noise were varied in two separate experiments to determine how these variables affected speech intelligibility of the CAT items pronounced by a male talker. CONCLUSIONS: Test results demonstrate speech-to-noise ratio has a significant effect on speech intelligibility of the CAT items under all conditions. Pink noise generated the lowest speech intelligibility scores followed by multitalker babble and then white noise. A change in the overall level of pink noise had only small effect on CAT intelligibility.

Acoustic Stimulation↗
PubMed2005

Coherence and the speech intelligibility index.

The speech intelligibility index (SII) (ANSI S3.5-1997) provides a means for estimating speech intelligibility under conditions of additive stationary noise or bandwidth reduction. The SII concept for estimating intelligibility is extended in this paper to include broadband peak-clipping and center-clipping distortion, with the coherence between the input and output signals used to estimate the noise and distortion effects. The speech intelligibility predictions using the new procedure are compared with intelligibility scores obtained from normal-hearing and hearing-impaired subjects for conditions of additive noise and peak-clipping and center-clipping distortion. The most effective procedure divides the speech signal into low-, mid-, and high-level regions, computes the coherence SII separately for the signal segments in each region, and then estimates intelligibility from a weighted combination of the three coherence SII values.

Adolescent↗
PubMed2004

Connexin 26 (GJB2) gene-related deafness and speech intelligibility after cochlear implantation.

HYPOTHESIS: Speech intelligibility in children after cochlear implantation may depend on their deafness cause, including connexin 26 (GJB2) gene-related deafness. BACKGROUND: There is significant variability in the degree of intelligibility, or clarity, of children's speech after cochlear implantation. GJB2 gene-related deafness may be a factor, as preliminary data suggest that pathologic changes do not affect the spiral ganglion cells, which are the neural elements stimulated by the implant, thus favoring better results. METHODS: In an observational retrospective cohort study of pediatric cochlear implantees, 38 patients with nonsyndromic deafness of unknown cause and 1 with keratitisichthyosis-deafness syndrome underwent GJB2 mutation analysis using polymerase chain reaction amplification and direct sequencing. The primary outcome measure assessed was Speech Intelligibility Rating score from postoperative Year 1 (n = 39) to Year 5 (n = 17). Educational setting was considered as a secondary outcome measure. Statistical analysis was double-blinded, with patients and assessors of outcome unaware of GJB2 status. RESULTS: Fourteen patients had GJB2-related deafness and 25 had GJB2-unrelated deafness. Comparisons at Year 3 (n = 31) revealed intelligible speech achieved by 9 of 11 with GJB2-related deafness, compared with only 6 of 20 with GJB2-unrelated deafness (p = 0.017). Ordinal logistic regression analysis on Speech Intelligibility Rating scores found statistically significantly better scores in children with GJB2-related deafness (p < 0.05) both before and after adjustment for confounding variables. A larger proportion with GJB2-related deafness also attended mainstream school (p = 0.01). CONCLUSION: In pediatric cochlear implantees, GJB2-related deafness is a predictor of good speech intelligibility.

Child↗
PubMed2005

Amplified earmuffs: impact on speech intelligibility in industrial noise for listeners with hearing loss.

PURPOSE: To determine how amplified earmuffs affect the intelligibility of speech in noise for people with hearing loss, and to determine how various brands of amplified earmuffs compare in terms of speech intelligibility and electroacoustic response. METHOD: The Hearing in Noise Test (HINT) was used to measure the intelligibility of speech for 10 participants with hearing loss when they listened in a background of recorded industrial noise at 85 dBA. Participants listened with 3 different sets of amplified earmuffs (Peltor Tactical 7-S, Elvex COM 55, and Bilsom 707 Impact II), with a set of passive earmuffs (E-A-R Ultra 9000), and with ears unoccluded. Two measurements of sentence threshold were obtained under each of the 5 listening conditions. Gain was measured electroacoustically across a range of input levels and frequencies for each amplified earmuff. RESULTS: Electroacoustic measurements indicated that each electronic earmuff amplified at low input levels and attenuated at high input levels. However, gain characteristics varied greatly across devices. HINT sentence thresholds were not significantly different across the 5 listening conditions or across the 2 trials. CONCLUSION: Results suggest that each type of earmuff can be used to reduce the noise exposure of people with hearing loss without compromising their ability to understand speech.

Acoustic Impedance Tests↗
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↗