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Results for “Speech Intelligibility”

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PubMed2004

Speech intelligibility of the callsign acquisition test in a quiet environment.

This paper reports on preliminary experiments aimed at standardizing speech intelligibility of military Callsign Acquisition Test (CAT) using average power levels of callsign items measured by the Root Mean Square (RMS) and maximum power levels of callsign items (Peak). The results obtained indicate that at a minimum sound pressure level (SPL) of 10.57 dBHL, the CAT tests were more difficult than NU-6 (Northwestern University, Auditory Test No. 6) and CID-W22 (Central Institute for the Deaf, Test W-22). At the maximum SPL values, the CAT tests reveal more intelligibility than NU-6 and CID-W22. The CAT-Peak test attained 95% intelligibility as NU-6 at 27.5 dBHL, and with CID-W22, 92.4% intelligibility at 27 dBHL. The CAT-RMS achieved 90% intelligibility when compared with NU-6, and 87% intelligibility score when compared with CID-W22; all at 24 dBHL.

Adolescent↗

PubMed1996

Speech intelligibility prediction in hearing-impaired listeners based on a psychoacoustically motivated perception model.

Sensorneural hearing-impaired listeners suffer severely from deterioration in the processing and internal representation of acoustic signals. In order to understand this deterioration in detail, a numerical perception model was developed which is based on current functional models of the signal processing in the auditory system. To test this model, the individual's speech intelligibility in quiet and in noise was predicted. The primary input parameter of the model is the precisely measured audiogram of each listener. In a refined version of the model, additional input parameters are derived from predicting the individual's temporal forward masking and notched-noise measurements with the same model assumptions. The predictions of the perception model were compared with those of the articulation index (AI) and the speech transmission index (STI). The accuracy of prediction with the perception model is in the same range as with the AI and the STI. The model does not require a calibration function and has the advantage of a greater flexibility in including different processing deficits associated with hearing impairment. However, it requires more time for computation. For the hearing-impaired listeners examined so far the individually measured psychoacoustical parameters have only a secondary effect on the prediction as compared to the audiogram. Nevertheless, the underlying model is a first step toward a quantitative understanding of speech intelligibility and helps to distinguish between the influence of the "attenuation" and the "distortion" component of the hearing loss.

Adult↗

PubMed1979

The relationship between information transfer and speech intelligibility of dysarthric speakers.

The purpose of this study was to determine the relationship between information transfer and speech intelligibility, as measured by single-word and paragraph transcription across a wide range od dysarthric speakers. Nine dysarthric speakers, including ataxic, spastic, and hypokinetic types, participated in the study. Their performance was judged by 108 listeners. The correlations between information transfer and paragraph and transcription scores and between information transfer and word transcription scores were high, i.e., 0.95 and 0.90, respectively. Word transcription scores tended to be slightly lower than information transfer scores for mildly dysarthric speakers. Clinical implications of these findings were discussed.

Adult↗

PubMed1988

The effect of head-induced interaural time and level differences on speech intelligibility in noise.

A study was made of the effect of interaural time delay (ITD) and acoustic headshadow on binaural speech intelligibility in noise. A free-field condition was simulated by presenting recordings, made with a KEMAR manikin in an anechoic room, through earphones. Recordings were made of speech, reproduced in front of the manikin, and of noise, emanating from seven angles in the azimuthal plane, ranging from 0 degree (frontal) to 180 degrees in steps of 30 degrees. From this noise, two signals were derived, one containing only ITD, the other containing only interaural level differences (ILD) due to headshadow. Using this material, speech reception thresholds (SRT) for sentences in noise were determined for a group of normal-hearing subjects. Results show that (1) for noise azimuths between 30 degrees and 150 degrees, the gain due to ITD lies between 3.9 and 5.1 dB, while the gain due to ILD ranges from 3.5 to 7.8 dB, and (2) ILD decreases the effectiveness of binaural unmasking due to ITD (on the average, the threshold shift drops from 4.6 to 2.6 dB). In a second experiment, also conducted with normal-hearing subjects, similar stimuli were used, but now presented monaurally or with an overall 20-dB attenuation in one channel, in order to simulate hearing loss. In addition, SRTs were determined for noise with fixed ITDs, for comparison with the results obtained with head-induced (frequency dependent) ITDs.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential Threshold↗

PubMed1998

Speech intelligibility following maxillectomy with and without a prosthesis: an analysis of 54 cases.

To statistically evaluate the factors that influenced speech following maxillectomy, the speech intelligibility (SI) in 54 patients was measured with and without a prosthesis. The mean SI score without a prosthesis in all patients was 35.7 +/- 22.7% and that with a prosthesis was 84.9 +/- 12.7%. The results of the postmaxillectomy SI statistical analysis revealed that an oro-nasal communication was one of the factors that influenced SI without a prosthesis. The resection of the anterior portion of the soft palate was one of the factors that influenced SI with a prosthesis, which suggested that for some of these patients we should consider specific surgical treatment, aimed at the reconstruction in the deep defect extending to the intratemporal fossa. A new classification of maxillary defects has been proposed which will help to predict the grade of post-maxillectomy speech disorder following surgery.

Adult↗

PubMed2000

Multi-channel compression and speech intelligibility in industrial noise.

This study examined how various forms of compression affect speech intelligibility in moderately high levels of industrial noise. Thirteen listeners with high-frequency sensorineural hearing loss were fit with a digital hearing aid programmed to operate in three modes of compression: compression limiting, compression of low frequencies only (BILL), and compression of high frequencies only (TILL). For each of these conditions, listeners attempted to recognize CID W-22 monosyllabic words delivered in a background of recorded industrial noise. Word recognition was also measured in quiet for the compression-limiting condition. The highest word identification scores were obtained in quiet (80.9%). Of the three conditions in which background noise was present, the mean score was highest for TILL compression (52.4%), and lowest for BILL (39.7%). Representative time-weighted average (TWA) exposures for each of the aided noise conditions were determined by means of a procedure outlined previously by the first author. The projected 8-hour amplified TWA with the hearing aid programmed to the TILL configuration was 94 dBA, whereas TWAs for the linear and BILL configurations were each 104 dBA. Thus, the highest intelligibility and lowest noise exposures were obtained with the aid in the TILL mode.

Adult↗

PubMed1980

Pediatric speech intelligibility test. I. Generation of test materials.

Normal children between 3 and 7 years of age generated word and sentence messages for use in a new speech intelligibility test. Word materials did not differ as a function of chronological age, vocabulary skills, or receptive language ability. Sentence materials, however, did reflect differences in chronological age, vocabulary skills, and receptive language skills. Older children, approximately 5-10 years, responded with complete, adult-like sentences. Younger children, approximately 3-10 years, responded with either a proform substituted for the noun phrase subject of a sentence or by omitting the auxiliary verb "be" in forming the present progressive verb tense of the sentence. To represent the differences in the children's responses, two different types of test sentences were formed. In one construction, the test sentence is composed of (noun phrase/verb-ing/noun phrase), preceded by the carrier phrase "show me", e.g., "Show me a bear brushing his teeth". In the other construction, the test sentence is composed of (noun phrase/auxiliary verb-ing/noun phrase), e.g., "A bear is brushing his teeth". The two different sentence forms are proposed as a means of equating differences in normal language development among children.

Age Factors↗

PubMed1987

Prediction of speech intelligibility for normal-hearing and cochlearly hearing-impaired listeners.

The word recognition ability of 4 normal-hearing and 13 cochlearly hearing-impaired listeners was evaluated. Filtered and unfiltered speech in quiet and in noise were presented monaurally through headphones. The noise varied over listening situations with regard to spectrum, level, and temporal envelope. Articulation index theory was applied to predict the results. Two calculation methods were used, both based on the ANSI S3.5-1969 20-band method [S3.5-1969 (American National Standards Institute, New York)]. Method I was almost identical to the ANSI method. Method II included a level- and hearing-loss-dependent calculation of masking of stationary and on-off gated noise signals and of self-masking of speech. Method II provided the best prediction capability, and it is concluded that speech intelligibility of cochlearly hearing-impaired listeners may also, to a first approximation, be predicted from articulation index theory.

Adult↗

PubMed2006

The effect of speech and speech intelligibility on task performance.

The aim of this study was to find out what are the effects of three different sound environments on performance of cognitive tasks of varying complexity. These three sound environments were 'speech', 'masked speech' and 'continuous noise'. They corresponded to poor, acceptable and perfect acoustical privacy in an open-plan office, respectively. The speech transmission indices were 0.00, 0.30 and 0.80, respectively. Sounds environments were presented at 48 dBA. The laboratory experiment on 36 subjects lasted for 4 h for each subject. Proofreading performance deteriorated in the 'speech' (p < 0.05) compared to the other two sound environments. Reading comprehension and computer-based tasks (simple and complex reaction time, subtraction, proposition, Stroop and vigilance) remained unaffected. Subjects assessed the 'speech' as the most disturbing, most disadvantageous and least pleasant environment (p < 0.01). 'Continuous noise' annoyed the least. Subjective arousal was highest in 'masked speech' and lowest in 'continuous noise' (p < 0.05). Performance in real open-plan offices could be improved by reducing speech intelligibility, e.g. by attenuating speech level and using an appropriate masking environment.

Adult↗

PubMedDate not supplied

Speech intelligibility in noisy environments with one- and two-microphone hearing aids.

In this study speech intelligibility in background noise was evaluated with 10 binaural hearing-aid users for hearing aids with one omnidirectional microphone and a hearing aid with a two-microphone configuration (enabling an omnidirectional as well as a directional mode). Signal-to-noise ratio (SNR) measurements were carried out for three different types of background noise (speech-weighted noise, traffic noise and restaurant noise) and two kinds of speech material (bisyllabic word lists and sentences). The average SNR improvement of the directional microphone configuration relative to the omnidirectional one was 3.4 dB for noise presented from 90 degrees azimuth. This improvement was independent of the specific type of noise and speech material, indicating that one speech-in-noise condition may yield enough relevant information in the evaluation of directional microphones and speech understanding in noise.

Adolescent↗

PubMed2006

Evidence against the mismatched interlanguage speech intelligibility benefit hypothesis.

In a follow-up study to that of Bent and Bradlow (2003), carrier sentences containing familiar keywords were read aloud by five talkers (Korean high proficiency; Korean low proficiency; Saudi Arabian high proficiency; Saudi Arabian low proficiency; native English). The intelligibility of these keywords to 50 listeners in four first language groups (Korean, n = 10; Saudi Arabian, n = 10; native English, n = 10; other mixed first languages, n = 20) was measured in a word recognition test. In each case, the non-native listeners found the non-native low-proficiency talkers who did not share the same first language as the listeners the least intelligible, at statistically significant levels, while not finding the low-proficiency talker who shared their own first language similarly unintelligible. These findings indicate a mismatched interlanguage speech intelligibility detriment for low-proficiency non-native speakers and a potential intelligibility problem between mismatched first language low-proficiency speakers unfamiliar with each others' accents in English. There was no strong evidence to support either an intelligibility benefit for the high-proficiency non-native talkers to the listeners from a different first language background or to indicate that the native talkers were more intelligible than the high-proficiency non-native talkers to any of the listeners.

Adult↗

PubMed1998

Increasing speech intelligibility in children with autism.

Accumulating studies are documenting specific motivational variables that, when combined into a naturalistic teaching paradigm, reliably influence the effectiveness of language teaching interactions for children with autism. However, the effectiveness of this approach has not yet been assessed with respect to improving speech intelligibility. The purpose of this study was to systematically compare two intervention conditions, a Naturalistic approach (which incorporated motivational variables) vs. an Analog (more traditional, structured) approach, with developmentally similar speech sounds equated within and across conditions for each child. Data indicate that although both methods effectively increased correct production of the target sounds under some conditions, functional use of the target sounds in conversation occurred only when the naturalistic procedures were used during intervention. Results are discussed in terms of pivotal variables that may produce improvements in speech sounds during conversational speech.

Articulation Disorders↗

PubMed1995

Temporal envelope and fine structure cues for speech intelligibility.

This paper describes a number of listening experiments to investigate the relative contribution of temporal envelope modulations and fine structure to speech intelligibility. The amplitude envelopes of 24 1/4-oct bands (covering 100-6400 Hz) were processed in several ways (e.g., fast compression) in order to assess the importance of the modulation peaks and troughs. Results for 60 normal-hearing subjects show that reduction of modulations by the addition of noise is more detrimental to sentence intelligibility than the same degree of reduction achieved by direct manipulation of the envelope; in some cases the benefit in speech-reception threshold (SRT) is almost 7 dB. Two crossover levels can be defined in dividing the temporal envelope into two equally important parts. The first crossover level divides the envelope into two perceptually equal parts: Removing modulations either chi dB below or above that level yields the same intelligibility score. The second crossover level divides the envelope into two acoustically equal peak and trough parts. The perceptual level is 9-12 dB higher than the acoustic level, indicating that envelope peaks are perceptually more important than troughs. Further results showed that 24 intact temporal speech envelopes with noise fine structure retain perfect intelligibility. In general, for the present type of signal manipulations, no one-to-one relation between the modulation-transfer function and the intelligibility scores could be established.

Adolescent↗

PubMed1975

Articulation patterns and speech intelligibility of 54 Vietnamese children with unoperated oral clefts: clinical observations and impressions.

Evaluations of the articulation patterns and speech intelligibility of 54 Vietnamese children with unrepaired oral clefts indicate a relationship between the type of oral cleft and the proficiency of speech skills attained. The results of the study suggest that consideration of the type of oral cleft and the specific kinds of articulation errors exhibited by the patient may be of value in planning the surgical habilitation of older children and adults with unrepaired clefts of the lip and palate.

Adolescent↗

PubMed1995

Intelligible speech encoded in the human brain stem frequency-following response.

The human brain stem frequency-following response (FFR) registers phase-locked neural activity to cyclical auditory stimuli. We show that the FFR can be elicited by word stimuli, and when speech-evoked FFTs are reproduced as auditory stimuli they are heard as intelligible speech. Stimuli were 10 high- and 10 low-probability words drawn from normative verbal responses of university students. Horizontal and vertical dipole FFRs based on 1000 repetitions of each word were recorded from two different participants. Speech-evoked FFRs were evaluated by 80 listeners. The results showed significant effects of FFR participant, word probability, and whether or not words were presented with category cues. Depending on such subject and experimental variables, FFRs were correctly perceived from 5% to 92% of the time.

Acoustic Stimulation↗

PubMed2005

Speech intelligibility and spatial release from masking in young children.

Children between the ages of 4 and 7 and adults were tested in free field on speech intelligibility using a four-alternative forced choice paradigm with spondees. Target speech was presented from front (0 degrees); speech or modulated speech-shaped-noise competitors were either in front or on the right (90 degrees). Speech reception thresholds were measured adaptively using a three-down/one-up algorithm. The primary difference between children and adults was seen in elevated thresholds in children in quiet and in all masked conditions. For both age groups, masking was greater with the speech-noise versus speech competitor and with two versus one competitor(s). Masking was also greater when the competitors were located in front compared with the right. The amount of masking did not differ across the two age groups. Spatial release from masking was similar in the two age groups, except for in the one-speech condition, when it was greater in children than adults. These findings suggest that, similar to adults, young children are able to utilize spatial and/or head shadow cues to segregate sounds in noisy environments. The potential utility of the measures used here for studying hearing-impaired children is also discussed.

Adult↗

PubMed1982

Pure-tone and speech intelligibility disturbances in patients with ototoxic disorders.

The prevalence and severity of hearing impairment caused by ototoxic drugs are surprisingly high. This emphasizes the importance of the questions arising from the treatment. In 33.7% of the cases, the hearing impairment caused by ototoxic antibiotics was of severe degree and in 25.4%, it was extremely severe. Parenteral, topical or oral administration of aminioglycoside antibiotics is dangerous. Because of the very poor speech intelligibility, most probably not only the spiral organ but the vestibulocochlear nerve and the higher auditory pathways are also affected by these antibiotics. In some cases, the severe distortion in sound perception cannot be compensated even by a hearing aid of the best quality, and lip-reading which was advised occasionally was without any result. To prevent these toxic effects, these drugs should be administered very parsimoniously and then under very strict conditions and close control.

Aminoglycosides↗

PubMed2004

The effect of the speaker gender on speech intelligibility in normal-hearing subjects with simulated high frequency hearing loss.

OBJECTIVE: To determine whether speaker gender affects speech discrimination scores, in normal hearing and simulated high frequency hearing loss situations. MATERIALS AND METHODS: Listeners were twenty normal volunteers. The speech stimuli were eight phonetically balanced monosyllabic word lists, uttered by a male and a female speakers. These lists were low-pass filtered at 1500, 2500 and 3500 Hz's to represent high frequency hearing loss. To obtain speech discrimination scores, the subjects listened to each of the eight lists in a different filtering and talker conditions in a randomized order. For statistical analysis, Mann-Whitney U test was used. RESULTS: In normal hearing situation, the scores obtained by male and female speeches, were similar (p=0.60). On the contrary, statistically significant differences were observed in all of the three high frequency hearing loss situations (p<0.01). CONCLUSION: Female speech is significantly more difficult to discriminate than male speech in normal-hearing subjects with simulated high frequency hearing loss and probably in patients with high frequency hearing loss.

Adult↗