PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Speech Intelligibility”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMed2002

Effects of multi-channel compression time constants on subjectively perceived sound quality and speech intelligibility.

OBJECTIVE: The purpose of this study was to determine the influence of the compression time constants in a multi-channel compression hearing aid on both subjectively assessed speech intelligibility and sound quality in realistic binaural acoustical situations for normal-hearing and hearing-impaired listeners. DESIGN: A nonlinear hearing aid with 15 independent compression channels of approximated critical bandwidth was simulated on a personal computer. Various everyday life situations containing different sounds such as speech and speech in noise were recorded binaurally through original hearing aid microphones placed in BTE hearing aid cases. Two experiments were run with normal hearing and hearing-impaired subjects. For each subject, hearing thresholds were established using in situ audiometry. The static I/O-curve parameters in all channels of the hearing aid were then adjusted so that normal speech received an insertion gain corresponding to the NAL-R formula (Byrne & Dillon, 1986). The compression ratio was kept constant at 2.1:1. In the first experiment with six normal-hearing and six hearing-impaired subjects, the hearing aid was programmed to four different settings by changing only the compression time constants while all the parameters describing the static nonlinear Input/Output-curve were kept constant. The compression threshold was set to a very low value. In the second experiment with seven normal-hearing and eight hearing-impaired subjects, the hearing aid was programmed to four settings by changing the release time constants and the compression threshold while all other remaining parameters were kept constant. Using a complete A/B pair comparison procedure, subjects were presented binaurally with the amplified sounds and asked to subjectively assess their preference for each hearing aid setting with regards to speech intelligibility and sound quality. RESULTS AND CONCLUSIONS: In Experiment 1, all subjects showed a significant preference for the longest release time (4 sec) over the two shorter release times (400 msec and 40 msec), pertaining to quality and intelligibility. In combination with the long release time, the attack time (1 msec or 100 msec) was of less importance. Larger inter-individual differences were observed among all subjects with regard to the perceived sound quality of musical and nonspeech signals. In Experiment 2 the hearing-impaired subjects showed a significant preference for the hearing aid setting with a long release time (4 sec) and a low compression threshold (20 dB SPL), both with regard to sound quality and speech intelligibility. With a short release time (40 msec), a lower compression threshold (20 dB SPL) was preferred over a higher threshold (50 dB SPL). Among normal-hearing subjects, the same settings were also preferred for speech intelligibility. However, no significant differences were observed in these subjects regarding the assessment of sound quality. Again, more individual variability was found during the assessment of music and nonspeech signals. In sum, the preference of a rather long release time raises the question of whether a compression system with a very short time constant is the optimal means to compensate for the sensory recruitment phenomenon.

Acoustic Stimulation↗
PubMed2004

Speech intelligibility and quality of life in head and neck cancer survivors.

OBJECTIVE: Poor speech intelligibility adversely affects quality of life self-assessment in long term survivors of head and neck cancer treatment. STUDY DESIGN: Observational case series including both objective clinical speech testing and subjective quality of life questionnaire administration. METHODS: Five-year head and neck cancer survivors were recruited to study the association between speech intelligibility and quality of life. Survivors were analyzed as an entire group, and also subdivided into laryngectomees and non-laryngectomees. Objective testing included sentence and word intelligibility. Subjective testing included quality of life questionnaires (UWQOL, FACT, FACT-head and neck, and PSS-HN) and a locally prepared "cancer concern" question. Associations were sought between intelligibility, quality of life and demographics. RESULTS: Sixty-two survivors underwent testing. Lower sentence intelligibility and word intelligibility scores were associated with diminished self-perceived UWQOL Speech (P = .0001 and P = .0001, respectively) and PSS-HN Understandability of Speech (P = .009 and P = .005). Decreased word intelligibility was additionally associated with decreased UWQOL Chewing (P = .003), UWQOL Swallowing (P = .02), UWQOL Recreation (P = .05), PSS-HN Willingness to Eat in Public (P = .03), and PSS-HN Normalcy of Diet (P = .0001). The associations continued even after patients who had undergone laryngectomy were excluded. CONCLUSIONS: Long-term survivors of head and neck cancer continue to have both objective and subjective deficits in speech parameters five years after treatment. Objective deficits are associated with subjective concerns about speech, eating, and recreation. Understanding how communication deficits affect quality of life in long-term head and neck cancer survivors may allow more effective therapies to modulate these concerns in the recovery period.

Female↗
PubMed2004

Cochlear implantation in children deafened by cytomegalovirus: speech perception and speech intelligibility outcomes.

BACKGROUND: Concerns have been expressed with regard to suitability for cochlear implantation of children deafened by cytomegalovirus because of possible coexisting central disorders/learning difficulties. The aim of the current study was to assess speech perception and intelligibility of speech produced by children deafened by cytomegalovirus and compare their progress with that of congenitally deaf children after cochlear implantation. METHODS: The study assessed 16 implanted children who were deafened by cytomegalovirus, using the Iowa Closed Sentence Test and Speech Intelligibility Rating. The results were compared with those of a group of 131 children who had undergone implantation who were congenitally deaf but did not have cytomegalovirus as the cause of deafness. The mean age at implantation was 3.9 years for the cytomegalovirus group (median, 3.5 years) and 4.1 years (median, 4 years) for the congenitally deaf children. They all received the Nucleus multichannel cochlear implant system. The follow-up period ranged from 1 to 5 years after implantation for both groups. RESULTS: After cochlear implantation, the intelligibility of speech produced by children deafened by cytomegalovirus had a wide range, varying from unintelligible speech to connected speech intelligible to all listeners. Relative to the median score for the control group at the last evaluation interval, 3 of the 16 children with cytomegalovirus (19%) performed better, 8 children (50%) performed more poorly, and 5 (31%) performed the same. The difference between the two groups was not statistically significant (p > 0.05). With regard to speech perception Iowa Sentence Test (Level B), relative to the median score for the control group at the last evaluation interval, 5 of the 16 children with cytomegalovirus (31%) performed better, 3 children (19%) performed more poorly, and 8 (50%) performed the same. The difference between the two groups was not statistically significant (p > 0.05). With regard to Level A and relative to the median score for the control group at the last evaluation interval, 1 of the 16 children with cytomegalovirus (6%) performed better, 6 children (38%) performed more poorly, and 9 (56%) performed the same. The difference between the two groups was statistically significant (p = 0.04). CONCLUSION: The results of the current study showed that cytomegalovirus alone, as a cause of deafness, is not a contraindication for cochlear implantation. Parents should be informed about the wide range of linguistic outcomes after implantation and that these children may need more specific or intensive rehabilitation. Although additional problems are common and outcomes may, on average, be poorer, cochlear implantation can provide useful auditory input to these children. Further research is needed to identify factors associated with cytomegalovirus that may influence the outcomes.

Case-Control Studies↗
PubMed2006

Experimental comparison between speech transmission index, rapid speech transmission index, and speech intelligibility index.

During the acoustical design of, e.g., auditoria or open-plan offices, it is important to know how speech can be perceived in various parts of the room. Different objective methods have been developed to measure and predict speech intelligibility, and these have been extensively used in various spaces. In this study, two such methods were compared, the speech transmission index (STI) and the speech intelligibility index (SII). Also the simplification of the STI, the room acoustics speech transmission index (RASTI), was considered. These quantities are all based on determining an apparent speech-to-noise ratio on selected frequency bands and summing them using a specific weighting. For comparison, some data were needed on the possible differences of these methods resulting from the calculation scheme and also measuring equipment. Their prediction accuracy was also of interest. Measurements were made in a laboratory having adjustable noise level and absorption, and in a real auditorium. It was found that the measurement equipment, especially the selection of the loudspeaker, can greatly affect the accuracy of the results. The prediction accuracy of the RASTI was found acceptable, if the input values for the prediction are accurately known, even though the studied space was not ideally diffuse.

Audiometry, Speech↗
PubMed1996

A source impedance compensated artificial voice for mask speech intelligibility testing: Thevenin model.

This paper describes the development of a Thevenin model of the human voice for mask speech intelligibility testing. The following steps were used to develop the Thevenin model: (1) the long-term average speech spectrum of ten male speakers was measured; (2) the corresponding average vocal tract shape was estimated using linear prediction; (3) a Thevenin model of the voice was determined based on the vocal tract shape. Electroacoustic analogs are used to predict the mask speech spectra produced by the Thevenin model and a mouth simulator consisting of a loudspeaker equalized for free-air speech. Comparing the two spectra allows us to examine how the interaction between the driving point impedance of the voice and the load impedance of a mask affects objective speech intelligibility measurements. The Thevenin model is used in a voice simulator that is described in a future paper.

Humans↗
PubMed1991

Comparison of three hearing aid fittings using the Speech Intelligibility Rating (SIR) Test.

This study compared the effects of three different hearing aids on subjective ratings of speech intelligibility. Insertion gain measurements on KEMAR indicated that the hearing aid fittings differed primarily in midfrequency gain. The test passages of the Speech Intelligibility Rating Test (SIR) were recorded onto tape through each hearing aid. The processed passages were presented monaurally to 13 subjects with hearing loss limited to frequencies above 2000 Hz. They rated five passages through each frequency responses (FR) in a randomized order. Each subject was retested within 2 or 3 days to assess test-retest reliability. Results indicated that the FR with the most midfrequency amplification did not differ significantly from the aid with the least amount of midfrequency gain. However, the FR with intermediate midfrequency gain received significantly lower ratings than did FR with most gain. Examination of the data from individual subjects indicated that the SIR results did not show differences among the FRs for the majority of subjects.

Acoustics↗
PubMed1986

The relative effects of three expressive methods upon the speech intelligibility of profoundly deaf speakers.

Two studies, conducted over a nine month interval, were designed to evaluate the relative effects of three expressive methods (speech alone, speech and signs, and speech with cues) upon speech intelligibility. Five profoundly deaf adults, who were receiving continuous speech training, were recorded reading lists of individual words under all three expressive modes. Listeners were required to identify through a multiple choice format the target stimuli from auditory presentations only. Study I results indicated that speech with cues produced the highest level of intelligibility, while speech and signs produced the lowest level. Study II, with an expanded set of word stimuli, found that speech alone produced a 65% rate of correct identification by listeners; speech and signs again produced the lowest rate of correct identifications. Implications for the assessment and understanding of speech intelligibility are considered.

Adult↗
PubMed1985

Alaryngeal speech intelligibility and the older listener.

Past investigations of alaryngeal speech intelligibility have focused on comparative intelligibility as perceived by young normally hearing adults. However, the spouses and social companions of laryngectomees may have significantly different auditory capabilities compared to young listeners. This report presents a comparison of alaryngeal and laryngeal speech identification performance for a group of young normally hearing listeners and a group of older adult listeners representative of the age of the laryngectomee's social companions. The speech signals investigated included normal laryngeal speech, artificial larynx speech, traditional esophageal speech, and tracheoesophageal speech. The results obtained reveal not only differences in speech signals but also a difference in the proficiency of speech perception for the two groups, favoring the younger listeners. The results of the speech identification measures in the presence of auditory competition revealed greatest intelligibility for the artificial larynx speech signal and poorest for the tracheoesophageal speech signal.

Adult↗
PubMed2006

Auralization study of optimum reverberation times for speech intelligibility for normal and hearing-impaired listeners in classrooms with diffuse sound fields.

Speech-intelligibility tests auralized in a virtual classroom were used to investigate the optimal reverberation times for verbal communication for normal-hearing and hearing-impaired adults. The idealized classroom had simple geometry, uniform surface absorption, and an approximately diffuse sound field. It contained a speech source, a listener at a receiver position, and a noise source located at one of two positions. The relative output levels of the speech and noise sources were varied, along with the surface absorption and the corresponding reverberation time. The binaural impulse responses of the speech and noise sources in each classroom configuration were convolved with Modified Rhyme Test (MRT) and babble-noise signals. The resulting signals were presented to normal-hearing and hearing-impaired adult subjects to identify the configurations that gave the highest speech intelligibilities for the two groups. For both subject groups, when the speech source was closer to the listener than the noise source, the optimal reverberation time was zero. When the noise source was closer to the listener than the speech source, the optimal reverberation time included both zero and nonzero values. The results generally support previous theoretical results.

Acoustics↗
PubMedDate not supplied

Restoration of intelligible speech 13 years post-head injury.

This case study demonstrates the efficacy of treatment of a patient with severe dysarthria long after the accepted period of 'neurological recovery'. A physiological approach to treatment was utilized and resulted in a change from non-verbal communication to functional verbal communication.

Adult↗
PubMed2001

Using statistical decision theory to predict speech intelligibility. II. Measurement and prediction of consonant-discrimination performance.

The speech recognition sensitivity (SRS) model [H. Müsch and S. Buus, J. Acoust. Soc. Am. 109, 2896-2909 (2001)] was tested by applying it to consonant-discrimination data collected in this study. Normally hearing listeners' abilities to discriminate among 18 consonants were measured in 58 filter conditions using two test paradigms. In one paradigm, listeners chose among all 18 stimuli. In the other, response alternatives were restricted to the correct response and eight consonants that were randomly selected among the 17 incorrect response alternatives. The effect of the number of response alternatives on performance can be described by statistical decision theory. Most filter conditions included one or more sharply filtered narrow bands of speech. Depending on the selection of bands, listeners' performance in multi-band conditions falls short of, equals, or exceeds the performance expected from multiplication of the error rates in the individual bands. The performance advantage in multi-band conditions increases with average band separation. The SRS model provides a good fit to the data and predicts the data more accurately than does the speech intelligibility index.

Adult↗
PubMed1987

Relations between speech intelligibility and psychoacoustical modulation transfer function (PMTF).

The modulation transfer function, MTF, has proved to be a powerful measure for predicting speech intelligibility in speech transmission channels. We extended it to include the ear, by measuring the psycho-acoustical MTF, i.e. the PMTF. Tone thresholds of 11 normal-hearing and 20 hearing-impaired subjects were measured in presence of unmodulated and intensity modulated noise. Octave frequencies from 500 to 4,000 Hz were used. The noise was octave filtered around the frequency of the probe tone. Six modulation frequencies from 1 to 50 Hz were used. From these results the PMTFs were calculated, as well as the corresponding psycho-acoustical speech transmission indices, i.e. the PSTIs. The subjects' speech discrimination scores in quiet and speech reception thresholds in noise were also measured. A correlation coefficient of 0.85 between the speech discrimination score in quiet and the PSTI was obtained. For the speech reception threshold in noise and the PSTI, the correlation was 0.71. The first of these two figures is promising, but our method needs some improvement, as it gave some problems due to fatigue effects.

Hearing Loss, Sensorineural↗
PubMed1994

The effects of syllabic compression and frequency shaping on speech intelligibility in hearing impaired people.

The effect of syllabic compression on speech intelligibility is rarely positive and in those cases that positive effects have been found, the same positive results could in general be obtained by frequency shaping of the frequency response curve. We programmed a syllabic compressor on a digital processor; the compressor differed from a conventional syllabic compressor by incorporating a delay in the signal path to suppress overshoots and thus minimize transient distortion. Furthermore, the time constants were short: attack time of 5 msec and release time of 15 msec. The compressor was only active in the high-frequency band. An essentially linear signal was added to deliver the low-frequency speech components. The processing resulted in a frequency response that mirrored the hearing loss near threshold and became much flatter for higher level input signals. Speech intelligibility scores for nonsense consonant-vowel-consonant words embedded in carrier phrases were determined for hearing-impaired persons with sloping audiograms and discrimination losses for speech. Results showed little additional effect of frequency shaping to the existing improved speech score for compressed speech. Optimum results were found for a compression ratio 2 with lower speech scores for linear amplification and for compression ratio 8. We next determined the effect of providing high-frequency emphasis to the speech signal and/or to the compression control signal to compensate for the upward spread of masking. The frequency response at the root-mean-square level was adjusted according to the half-gain rule. The positive effects of moderate compression could be found again; the high-frequency emphasis, however, was positive for the vowels but made consonant recognition poorer.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMed1990

[Speech intelligibility in tongue and mouth-floor cancer patients who received surgical excisions after induction therapy].

Speech intelligibility has been investigated in 40 patients who had received a glossotomy because of tongue and/or mouth floor carcinomas after preoperative induction therapy. The results are summarized below. 1. Speech was clearer and better understood in intelligibility tests than by tests of single sounds. 2. Speech intelligibility was impaired in 12 patients. The impairment degree was mild (slight difficulty in understanding the spoken content) in 9 cases, where as the speech in the remaining patients was moderately or severely impaired. 3. Hardly any speech impairment resulted when the tongue resection was limited to the ipsilateral 1/3 of the tongue, where as the impairment was greater in cases who received a glossotomy over that limit. 4. Tongue mobility was related to speech intelligibility, and conservation of the tongue tip appeared important. 5. Aggressive induction therapy made limited surgical extirpation possible, and many patients speech functions were well preserved by conservative surgery. Together with good local control, aggressive induction therapy seemed to be beneficial for tongue and mouth-floor carcinomas.

Adult↗
PubMed2001

The effect of intensity perturbations on speech intelligibility for normal-hearing and hearing-impaired listeners.

Hearing-impaired listeners are known to suffer from reduced speech intelligibility in noise, even if sounds are above their hearing thresholds. This study examined the possible contribution of reduced acuity of intensity coding to this problem. The "distortion-sensitivity model" was used: the effect of reduced acuity of auditory intensity coding on intelligibility was mimicked by an artificial distortion of the speech intensity coding, and the sensitivity to this distortion for hearing-impaired listeners was compared with that for normal-hearing listeners. Stimuli (speech plus noise) were wavelet coded using a Gaussian wavelet (1/4-octave bandwidth). The intensity coding was distorted by multiplying the modulus of each wavelet coefficient by a random factor. Speech-reception thresholds (SRTs) were measured for various degrees of intensity perturbation. Hearing-impaired listeners were classified as suffering from suprathreshold deficits if intelligibility of undistorted speech was worse than predicted from audibility by the speech intelligibility index model [ANSI, ANSI S3.5-1997 (1997)]. Hearing-impaired listeners without suprathreshold deficits were as sensitive to the intensity distortion as the normal-hearing listeners. Hearing-impaired listeners with suprathreshold deficits appeared to be less sensitive. Results indicate that reduced acuity of auditory intensity coding may be a factor underlying reduced speech intelligibility in noise for the hearing impaired.

Adult↗
PubMed1987

Validation of the pediatric speech intelligibility test in children with central nervous system lesions.

The pediatric speech intelligibility (PSI) test was administered to 21 children with a variety of documented central nervous system (CNS) lesions. Ages ranged from 3 to 8 years. PSI test results demonstrated both high sensitivity and high specificity. Results were consistently (1) abnormal in children with lesions in areas of the brain important for auditory function (CNS auditory disorders) and (2) normal in children with lesions in areas anatomically remote from auditory nuclei and pathways (nonauditory CNS disorders).

Auditory Threshold↗
PubMed1989

Improvement of speech intelligibility by a secondary operation to mobilize the tongue after glossectomy.

To prove the hypothesis that speech after glossectomy would be improved more by increasing the mobility of the remaining tongue rather than by increasing its volume, the speech intelligibility of 4 glossectomy patients was investigated before and after a secondary operation in which a split skin graft was used to mobilize the residual tongue. In each case, the postoperative speech intelligibility scores were higher than preoperative ones (case 1:83.6 to 97.2%, case 2: 76.6 to 82.5%, case 3: 51.5 to 58.5%, case 4: 30.2 to 49.3%). Sounds produced with the rear portion of the tongue were improved in 3 cases, and plosive and affricative sounds were remarkably improved in all cases. These results were considered to be due to the increased mobility, especially the mid and rear portions of the tongue.

Adult↗