Sentence Recognition Threshold Research Articles

Barriers to Early Progress in Adult Cochlear Implant Outcomes.

Adult cochlear implant (CI) recipients obtain varying levels of speech perception from their device. Adult CI users adapt quickly to their CI if they have no peripheral "bottom-up" or neurocognitive "top-down" limiting factors. Our objective here was to understand the influence of limiting factors on the progression of sentence understanding in quiet and in noise, initially and over time. We hypothesized that the presence of limiting factors, detected using a short test battery, would predictably influence sentence recognition with practical consequences. We aimed to validate the test battery by comparing the presence of limiting factors and the success criteria of >90% sentence understanding in quiet 1 month after activation. The study was a single-clinic, cross-sectional, retrospective design incorporating 32 adult unilateral Nucleus CI users aged 27 to 90 years (mean = 70, SD = 13.5). Postoperative outcome was assessed through sentence recognition scores in quiet and in varying signal to noise ratios at 1 day, 1 to 2 months, and up to 2 years. Our clinic's standard test battery comprises physiological and neurocognitive measures. Physiological measures included electrically evoked compound action potentials for recovery function, spread of excitation, and polarity effect. To evaluate general cognitive function, inhibition, and phonological awareness, the Montreal Cognitive Assessment screening test, the Stroop Color-Word Test, and tests 3 and 4 of the French Assessment of Reading Skills in Adults over 16 years of age, respectively were performed. Physiological scores were considered abnormal, and therefore limiting, when total neural recovery periods and polarity effects, for both apical and basal electrode positions, were >1.65 SDs from the population mean. A spread of excitation of >6 electrode units was also considered limiting. For the neurocognitive tests, scores poorer than 1.65 SDs from published normal population means were considered limiting. At 1 month, 13 out of 32 CI users scored ≥90% sentence recognition in quiet with no significant dependence on age. Subjects with no limiting peripheral or neurocognitive factors were 8.5 times more likely to achieve ≥90% score in quiet at 1 month after CI switch-on (p = 0.010). In our sample, we detected 4 out of 32 cases with peripheral limiting factors that related to neural health or poor electrode-neural interface at both apical and basal positions. In contrast, neurocognitive limiting factors were identified in 14 out of 32 subjects. Early sentence recognition scores were predictive of long-term sentence recognition thresholds in noise such that limiting factors appeared to be of continuous influence. Both peripheral and neurocognitive processing factors affect early sentence recognition after CI activation. Peripheral limiting factors may have been detected less often than neurocognitive limiting factors because they were defined using sample-based criteria versus normal population-based criteria. Early performance was generally predictive of long-term performance. Understanding the measurable covariables that limit CI performance may inform follow-up and improve counseling. A score of ≥90% for sentence recognition in quiet at 1 month may be used to define successful progress; whereas, lower scores indicate the need for diagnostic testing and ongoing rehabilitation. Our findings suggest that sentence test scores as early as 1 day after activation can provide vital information for the new CI user and indicate the need for rehabilitation follow-up.

Reabilitação auditiva com sistemas Baha® transcutâneo e percutâneo

ABSTRACT Purpose Longitudinally verify the influence of auditory tonal thresholds obtained with transcutaneous and percutaneous bone-anchored hearing aids on speech perception in individuals with external and/or middle ear malformation and chronic otitis media. Methods Observational, retrospective, longitudinal follow-up study of 30 unilateral users of the transcutaneous and percutaneous Baha® system for the collection of secondary data on pure tone thresholds obtained through free field audiometry and sentence recognition threshold in silence and noise in conditions: without the prosthesis; at the time of activation; in the first month of use (post 1); and in the third month (post 2). Results There was a significant difference between pure tone thresholds obtained at frequencies of 3 and 4kHz with better results for the percutaneous technique at all evaluation moments. For both systems, better performance was observed in sentence recognition in silence and in noise, with a significant difference in activation (p<0.001), but it remained stable during the other evaluation moments. The percutaneous system showed better benefit in recognizing sentences in noise only on activation (p=0.036), when compared to the transcutaneous system. Conclusion The percutaneous system provided better audibility for high frequencies; however, such audibility did not influence sentence recognition in the silent situation for both systems. For the noise situation, better responses were observed in the percutaneous system, however, the difference was not maintained over time.

Comparing the effects of target and masker voice familiarity on children’s speech-in-speech recognition

Familiarity with a target voice has been shown to aid spoken word recognition for both children and adults. Familiarity effects of a target voice are not well understood, and even less is known about the impacts of masker voice familiarity. The present study investigated long-term target and masker voice familiarity effects on children’s speech-in-speech recognition by using the child’s own mother’s voice as stimuli. Open-set sentence recognition thresholds (SRTs) were measured adaptively in a two-talker speech masker. Twenty children were tested in three conditions, hearing their mother’s voice and two unfamiliar female voices: (1) Familiar Target/Unfamiliar Masker; (2) Familiar Masker/Unfamiliar Target; and (3) Unfamiliar Target/Unfamiliar Masker. Condition 1 measured effects of target familiarity; Condition 2 examined effects of masker familiarity; Condition 3 served as baseline. Results showed SRTs were significantly better when target speech was spoken by a familiar talker (the mother). When background speech was spoken by the familiar talker, performance was worse relative to an unfamiliar masker. This suggests that children do benefit from long-term voice familiarity with the target but not the masker speech. Thus, voice familiarity may impact children’s ability to attend to the target speech but does not always improve segregation.

Effects of Conventional and Musician-Specific Hearing Protection Devices on Speech Intelligibility

(1) Background: To assess and compare speech intelligibility with conventional and universal musician-specific hearing protection devices (HPD); (2) Methods: The sample comprised 15 normal-hearing musicians of both sexes who had been professionals for more than 5 years. They underwent thorough audiological assessment and free-field audiometry to measure the attenuation levels of three HPD models (musician-specific, silicone, and foam devices). The sentence recognition thresholds in quiet (SRTQ) and noise (SRTN) were assessed with the Lists of Sentences in Portuguese. User satisfaction with musician HPD was assessed after 2 months; (3) Results: Conventional HPD had higher pure-tone mean attenuation levels than musician HPD. No statistically significant differences were found in SRTQ and SRTN between the three HPD types. However, the musician HPD had higher mean signal-to-noise ratios and percentages of correct words from sentences presented in noise than the other HPD. The answers also indicated a positive trend toward satisfaction with the musician-specific HPD; (4) Conclusions: Despite the lack of significant differences in speech intelligibility while wearing the three HPD models in either quiet or noise, the musician-specific HPD provided greater musical sound quality. This reinforces the possibility of an effective and adequate use of protection to preserve musicians’ hearing.

Relationship Between the Ability to Detect Frequency Changes or Temporal Gaps and Speech Perception Performance in Post-lingual Cochlear Implant Users.

Previous studies, using modulation stimuli, on the relative effects of frequency resolution and time resolution on CI users’ speech perception failed to reach a consistent conclusion. In this study, frequency change detection and temporal gap detection were used to investigate the frequency resolution and time resolution of CI users, respectively. Psychophysical and neurophysiological methods were used to simultaneously investigate the effects of frequency and time resolution on speech perception in post-lingual cochlear implant (CI) users. We investigated the effects of psychophysical results [frequency change detection threshold (FCDT), gap detection threshold (GDT)], and acoustic change complex (ACC) responses (evoked threshold, latency, or amplitude of ACC induced by frequency change or temporal gap) on speech perception [recognition rate of monosyllabic words, disyllabic words, sentences in quiet, and sentence recognition threshold (SRT) in noise]. Thirty-one adult post-lingual CI users of Mandarin Chinese were enrolled in the study. The stimuli used to induce ACCs to frequency changes were 800-ms pure tones (fundamental frequency was 1,000 Hz); the frequency change occurred at the midpoint of the tones, with six percentages of frequency changes (0, 2, 5, 10, 20, and 50%). Temporal silences with different durations (0, 5, 10, 20, 50, and 100 ms) were inserted in the middle of the 800-ms white noise to induce ACCs evoked by temporal gaps. The FCDT and GDT were obtained by two 2-alternative forced-choice procedures. The results showed no significant correlation between the CI hearing threshold and speech perception in the study participants. In the multiple regression analysis of the influence of simultaneous psychophysical measures and ACC responses on speech perception, GDT significantly predicted every speech perception index, and the ACC amplitude evoked by the temporal gap significantly predicted the recognition of disyllabic words in quiet and SRT in noise. We conclude that when the ability to detect frequency changes and the temporal gap is considered simultaneously, the ability to detect frequency changes may have no significant effect on speech perception, but the ability to detect temporal gaps could significantly predict speech perception.

The impact of temporally coherent visual and vibrotactile cues on speech perception in noise performance

The inputs delivered to different sensory organs provide us with complementary information about the environment. Our recent study demonstrated that presenting abstract visual information of speech envelopes substantially improves speech perception ability in normal-hearing (NH), listeners [Yuan et al., J. Acoust. Soc. Am. (2020)]. The purpose of this study was to expand this audiovisual speech perception to the tactile domain. Twenty adults participated in sentence recognition threshold measurements in four different sensory modalities (AO: auditory-only; AV: auditory-visual; AT: audio-tactile; and AVT: audio-visual-tactile). The target sentence [CRM speech corpus, Bolia et al., J. Acoust. Soc. Am. (2000)] level was fixed at 60 dBA, and the masker (speech-shaped noise) levels were adaptively varied to find masked thresholds. The amplitudes of both visual and vibrotactile stimuli were temporally synchronized and non-synchronized with the target speech envelope for comparison. Results show that temporally coherent multi-modal stimulation (AV, AT, and AVT) significantly improves speech perception ability when compared to audio-only (AO) stimulation. These multisensory speech perception benefits were reduced when the cross-modal temporal coherence characteristics were eliminated. These findings suggest that multisensory interactions are fundamentally important for speech perception ability in NH listeners. The outcome of this multisensory speech processing highly depends on temporal coherence characteristics between multi-modal sensory inputs.

Voice Emotion Recognition by Mandarin-Speaking Children with Cochlear Implants.

Emotional expressions are very important in social interactions. Children with cochlear implants can have voice emotion recognition deficits due to device limitations. Mandarin-speaking children with cochlear implants may face greater challenges than those speaking nontonal languages; the pitch information is not well preserved in cochlear implants, and such children could benefit from child-directed speech, which carries more exaggerated distinctive acoustic cues for different emotions. This study investigated voice emotion recognition, using both adult-directed and child-directed materials, in Mandarin-speaking children with cochlear implants compared with normal hearing peers. The authors hypothesized that both the children with cochlear implants and those with normal hearing would perform better with child-directed materials than with adult-directed materials. Thirty children (7.17-17 years of age) with cochlear implants and 27 children with normal hearing (6.92-17.08 years of age) were recruited in this study. Participants completed a nonverbal reasoning test, speech recognition tests, and a voice emotion recognition task. Children with cochlear implants over the age of 10 years also completed the Chinese version of the Nijmegen Cochlear Implant Questionnaire to evaluate the health-related quality of life. The voice emotion recognition task was a five-alternative, forced-choice paradigm, which contains sentences spoken with five emotions (happy, angry, sad, scared, and neutral) in a child-directed or adult-directed manner. Acoustic analyses showed substantial variations across emotions in all materials, mainly on measures of mean fundamental frequency and fundamental frequency range. Mandarin-speaking children with cochlear implants displayed a significantly poorer performance than normal hearing peers in voice emotion perception tasks, regardless of whether the performance is measured in accuracy scores, Hu value, or reaction time. Children with cochlear implants and children with normal hearing were mainly affected by the mean fundamental frequency in speech emotion recognition tasks. Chronological age had a significant effect on speech emotion recognition in children with normal hearing; however, there was no significant correlation between chronological age and accuracy scores in speech emotion recognition in children with implants. Significant effects of specific emotion and test materials (better performance with child-directed materials) in both groups of children were observed. Among the children with cochlear implants, age at implantation, percentage scores of nonverbal intelligence quotient test, and sentence recognition threshold in quiet could predict recognition performance in both accuracy scores and Hu values. Time wearing cochlear implant could predict reaction time in emotion perception tasks among children with cochlear implants. No correlation was observed between the accuracy score in voice emotion perception and the self-reported scores of health-related quality of life; however, the latter were significantly correlated with speech recognition skills among Mandarin-speaking children with cochlear implants. Mandarin-speaking children with cochlear implants could have significant deficits in voice emotion recognition tasks compared with their normally hearing peers and can benefit from the exaggerated prosody of child-directed speech. The effects of age at cochlear implantation, speech and language development, and cognition could play an important role in voice emotion perception by Mandarin-speaking children with cochlear implants.

Does Sentence-Level Coarticulation Affect Speech Recognition in Noise or a Speech Masker?

Purpose Three experiments were conducted to better understand the role of between-word coarticulation in masked speech recognition. Specifically, we explored whether naturally coarticulated sentences supported better masked speech recognition as compared to sentences derived from individually spoken concatenated words. We hypothesized that sentence recognition thresholds (SRTs) would be similar for coarticulated and concatenated sentences in a noise masker but would be better for coarticulated sentences in a speech masker. Method Sixty young adults participated (n = 20 per experiment). An adaptive tracking procedure was used to estimate SRTs in the presence of noise or two-talker speech maskers. Targets in Experiments 1 and 2 were matrix-style sentences, while targets in Experiment 3 were semantically meaningful sentences. All experiments included coarticulated and concatenated targets; Experiments 2 and 3 included a third target type, concatenated keyword-intensity-matched (KIM) sentences, in which the words were concatenated but individually scaled to replicate the intensity contours of the coarticulated sentences. Results Regression analyses evaluated the main effects of target type, masker type, and their interaction. Across all three experiments, effects of target type were small (< 2 dB). In Experiment 1, SRTs were slightly poorer for coarticulated than concatenated sentences. In Experiment 2, coarticulation facilitated speech recognition compared to the concatenated KIM condition. When listeners had access to semantic context (Experiment 3), a coarticulation benefit was observed in noise but not in the speech masker. Conclusions Overall, differences between SRTs for sentences with and without between-word coarticulation were small. Beneficial effects of coarticulation were only observed relative to the concatenated KIM targets; for unscaled concatenated targets, it appeared that consistent audibility across the sentence offsets any benefit of coarticulation. Contrary to our hypothesis, effects of coarticulation generally were not more pronounced in speech maskers than in noise maskers.

Influence of aided audibility on speech recognition performance with frequency composition for children and adults

Objective The primary purpose of this project was to evaluate the influence of speech audibility on speech recognition with frequency composition, a frequency-lowering algorithm used in hearing aids. Design Participants were tested to determine word and sentence recognition thresholds in background noise, with and without frequency composition. The audibility of speech was quantified using the speech intelligibility index (SII). Study Sample Participants included 17 children (ages 6–16) and 21 adults (ages 19 to 72) with bilateral mild-to-severe sensorineural hearing loss. Results Word and sentence recognition thresholds did not change significantly with frequency composition. Participants with better aided speech audibility had better speech recognition in noise, regardless of processing condition, than those with poorer aided audibility. For the child participants, changes in the word recognition threshold between processing conditions were predictable from aided speech audibility. However, this relationship depended strongly on one participant with a low SII and otherwise, changes in speech recognition between frequency composition off and on were not predicable from aided speech audibility. Conclusion While these results suggest that children who have a low-aided SII may benefit from frequency composition, further data are needed to generalise these findings to a greater number of participants and variety of stimuli.

Independent and Combined Effects of Fundamental Frequency and Vocal Tract Length Differences for School-Age Children's Sentence Recognition in a Two-Talker Masker.

Purpose The purpose of this study was to examine the independent and combined contributions of fundamental frequency (F0) and vocal tract length (VTL) differences on children's speech-in-speech recognition in the presence of a competing two-talker masker. Method Participants were 64 children (5-17 years old) and 25 adults (18-39 years old). Sentence recognition thresholds were measured in a two-talker masker. Target sentences had either the same mean F0 and VTL of the masker or were digitally altered so that the target and masker differed in F0 (Experiment 1), differed in VTL (Experiment 2), or differed in both F0 and VTL (Experiment 3). To determine the benefit, masking release was computed by subtracting thresholds in each shifted condition from the threshold in the unshifted condition. Results Results demonstrate that children's ability to benefit from either F0 or VTL differences (Experiments 1 and 2) depended on listener age, with younger children showing less improvement in speech reception thresholds compared to older children and adults. Age effects were also evident in the combined-cue conditions (Experiment 3), but children showed greater improvements compared to F0-only or VTL-only manipulations. Conclusions There was a prolonged pattern of development in children's ability to benefit from F0 or VTL differences between target and masker speech. Young children failed to capitalize on F0 and VTL differences to the same extent as older children and adults but did show a robust benefit when the cues were combined, supporting the hypothesis that younger children rely more heavily on redundant cues compared to older children and adults.

The Clear-Speech Benefit for School-Age Children: Speech-in-Noise and Speech-in-Speech Recognition.

Purpose Talkers often modify their speech when communicating with individuals who struggle to understand speech, such as listeners with hearing loss. This study evaluated the benefit of clear speech in school-age children and adults with normal hearing for speech-in-noise and speech-in-speech recognition. Method Masked sentence recognition thresholds were estimated for school-age children and adults using an adaptive procedure. In Experiment 1, the target and masker were summed and presented over a loudspeaker located directly in front of the listener. The masker was either speech-shaped noise or two-talker speech, and target sentences were produced using a clear or conversational speaking style. In Experiment 2, stimuli were presented over headphones. The two-talker speech masker was diotic (M0). Clear and conversational target sentences were presented either in-phase (T0) or out-of-phase (Tπ) between the two ears. The M0Tπ condition introduces a segregation cue that was expected to improve performance. Results For speech presented over a single loudspeaker (Experiment 1), the clear-speech benefit was independent of age for the noise masker, but it increased with age for the two-talker masker. Similar age effects for the two-talker speech masker were seen under headphones with diotic presentation (M0T0), but comparable clear-speech benefit as a function of age was observed with a binaural cue to facilitate segregation (M0Tπ). Conclusions Consistent with prior research, children showed a robust clear-speech benefit for speech-in-noise recognition. Immaturity in the ability to segregate target from masker speech may limit young children's ability to benefit from clear-speech modifications for speech-in-speech recognition under some conditions. When provided with a cue that facilitates segregation, children as young as 4-7 years of age derived a clear-speech benefit in a two-talker masker that was similar to the benefit experienced by adults.

Modulation masking release reduction as a function of time-compressed speech

ABSTRACT Purpose: to investigate the magnitude of the modulation masking release in sentence recognition as a function of compression level and modulation rate. Methods: sentences of the Brazilian Portuguese version of the Hearing in Noise Test sentences were used as stimulus. The sentence recognition thresholds were established as a function of speech compression level (0%, 33%, and 50%) in steady and modulated noise at different modulation rates (4, 10, 32 Hz). The analysis of variance was performed for repeated measures, using the 5% significance level. Results: sentence recognition thresholds were higher for higher compression levels in the different types of noise. However, thresholds were smaller for modulated noises. Also, the magnitude of modulation masking release decreased as speech compression level increased. Nevertheless, no difference was observed in compressed speech between different noise modulation rates, in relation to the speech compression level. Conclusion: the magnitude of the modulation masking release decreased as the speech time-compression increased. Also, the reductions in modulation masking release, in relation to the speech time-compression level, did not differ between the masking-noise modulation rates (4, 10, and 32 Hz).

The effects of wireless audio microphones on sentences recognition threshold for hearing aid users in noise

Objective:This study was aimed to observe the effects of wireless audio microphone on hearing aids effect in noise at different listening distances. Method:Twenty-three subjects with bilateral sensorineural hearing loss, including 17 males and 6 females were fitted with binaural hearing aids. These patients did sentences recognition tests at two different listening distance（1.5 and 3 meters） in noise. The subjects were tested under three conditions, ①with hearing aids alone; ②with the wireless audio microphone alone; ③with hearing aid microphone and mini audio microphone simultaneously. Result:The sentence recognition threshold at 3 meters listening distance is significantly higher than it at 1.5 meters listening distance with hearing aids alone（P<0.05）. There is no significant difference in the sentence recognition threshold between two listening distances when the wireless audio microphone was switched on（P>0.05）. Conclusion:Mini audio microphone can significantly improve hearing aids effect in long distance listening in noise.

The effect of target/masker fundamental frequency contour similarity on masked-speech recognition.

Greater informational masking is observed when the target and masker speech are more perceptually similar. Fundamental frequency (f0) contour, or the dynamic movement of f0, is thought to provide cues for segregating target speech presented in a speech masker. Most of the data demonstrating this effect have been collected using digitally modified stimuli. Less work has been done exploring the role of f0 contour for speech-in-speech recognition when all of the stimuli have been produced naturally. The goal of this project was to explore the importance of target and masker f0 contour similarity by manipulating the speaking style of talkers producing the target and masker speech streams. Sentence recognition thresholds were evaluated for target and masker speech that was produced with either flat, normal, or exaggerated speaking styles; performance was also measured in speech spectrum shaped noise and for conditions in which the stimuli were processed through an ideal-binary mask. Results confirmed that similarities in f0 contour depth elevated speech-in-speech recognition thresholds; however, when the target and masker had similar contour depths, targets with normal f0 contours were more resistant to masking than targets with flat or exaggerated contours. Differences in energetic masking across stimuli cannot account for these results.

Bilingualism and speech recognition in silence and noise in adults.

To compare the ability to recognize sentences in silence and in noise in monolingual normal-hearing Brazilian Portuguese speakers, and bilingual speakers of Brazilian Portuguese and German, and bilingual speakers of Brazilian Portuguese and Italian, as well as to analyze the influence of age of second language acquisition on the performance of bilinguals. 87 normal-hearing individuals aged between 18 and 55 years participated of this research. They were categorized into: Control Group, composed by 30 monolingual Brazilian Portuguese speakers; German Research Group, 31 simultaneous bilingual native speakers of Portuguese and speakers of German as a second language and; Italian Research Group, consisting of 26 successive bilinguals, native speakers of Portuguese and speakers of Italian as a second language. The Sentence List Test in Brazilian Portuguese was used to measure their Sentence Recognition Thresholds in Silence and Noise. In silence, there were no statistically significant differences in performance when comparing the bilingual to the monolingual individuals, and when comparing the bilingual speakers among themselves. On the other hand, in noise, there was a significant difference between the bilingual groups and the monolingual one. However, there were no significant differences between the bilingual groups when their performance was compared. Bilingualism positively influenced the development of language and listening skills, which led the bilinguals to outperform in speech recognition in the presence of noise. Also, the period of a second language acquisition did not influence bilingual performance.

Does the semantic content or syntactic regularity of masker speech affect speech-on-speech recognition?

Speech-on-speech recognition differs substantially across stimuli, but it is unclear what role linguistic features of the masker play in this variability. The linguistic similarity hypothesis suggests similarity between sentence-level semantic content of the target and masker speech increases masking. Sentence recognition in a two-talker masker was evaluated with respect to semantic content and syntactic structure of the masker (experiment 1) and linguistic similarity of the target and masker (experiment 2). Target and masker sentences were semantically meaningful or anomalous. Masker syntax was varied or the same across sentences. When other linguistic features of the masker were controlled, variability in syntactic structure across masker tokens was only relevant when the masker was played continuously (as opposed to gated); when played continuously, sentence-recognition thresholds were poorer with variable than consistent masker syntax, but this effect was small (0.5 dB). When the syntactic structure of the masker was held constant, semantic meaningfulness of the masker did not increase masking, and at times performance was better for the meaningful than the anomalous masker. These data indicate that sentence-level semantic content of the masker speech does not influence speech-on-speech masking. Further, no evidence that similarities between target/masker sentence-level semantic content increases masking was found.

Children’s ability to benefit from fundamental frequency and vocal tract length differences during speech-in-speech recognition

The present study evaluated whether children’s speech-in-speech recognition benefits from differences in fundamental frequency (F0) or vocal tract length (VTL) between the target and masker talkers’ voices. Children, like adults, can benefit from a sex mismatch between competing talkers, but the relative contribution of individual voice characteristics to children’s improved speech-in-speech understanding is unknown. In this study, we first tested children’s ability to use differences in either F0 or VTL between target and masker speech to evaluate the independent influence of these cues on speech-in-speech recognition. Then F0 and VTL differences were combined to determine whether cue redundancy would reduce the child/adult differences observed in these contexts. Sentence recognition thresholds were measured in a two-talker speech masker. All stimuli were recorded by the same female talker. F0 and VTL of the target sentences were manipulated using the pitch-synchronous overlap-add method. Preliminary results suggest a prolonged developmental trajectory in the ability to use F0 or VTL in isolation, but indicate that the combination of these cues benefits children at an earlier age compared to when either cue is presented in isolation. Adults showed the greatest benefit from the F0-only manipulation, showing no additional benefit when F0 and VTL were combined.

Speech-in-noise perception in unilateral hearing loss: Relation to pure-tone thresholds and brainstem plasticity.

We investigated speech recognition in noise in subjects with mild to profound levels of unilateral hearing loss. Thirty-five adults were evaluated using an adaptive signal-to-noise ratio (SNR50) sentence recognition threshold test in three spatial configurations. The results revealed a significant correlation between pure-tone average audiometric thresholds in the poorer ear and SNR thresholds in the two conditions where speech and noise were spatially separated: dichotic - with speech presented to the poorer ear and reverse dichotic - with speech presented to the better ear. This first result suggested that standard pure-tone air-conduction thresholds can be a reliable predictor of speech recognition in noise for binaural conditions. However, a subgroup of 14 subjects was found to have poorer-than-expected speech recognition scores, especially in the reverse dichotic listening condition. In this subgroup 9 subjects had been diagnosed with vestibular schwannoma at stage III or IV likely affecting the lower brainstem function. These subjects showed SNR thresholds in the reverse dichotic condition on average 4dB poorer (higher) than for the other 21 normally-performing subjects. For the 7 of 9 subjects whose vestibular schwannoma was removed, the deficit was no longer apparent on average 5 months following the surgical procedure. These results suggest that following unilateral hearing loss the capacity to use monaural spectral information is supported by the lower brainstem.

Reconhecimento de fala no ruído em sujeitos com audição normal e queixa de zumbido

RESUMO Introdução O desempenho auditivo para sons supraliminares pode estar comprometido, mesmo quando o audiograma é normal. Pacientes com zumbido sem perda auditiva queixam-se frequentemente de dificuldades de compreensão de fala, principalmente em ambientes ruidosos. Objetivo Investigar o desempenho em testes de fala com ruído, em indivíduos com limiares audiométricos normais, com e sem queixa de zumbido. Métodos Foram avaliados 20 sujeitos adultos, com idade entre 18 e 45 anos, com audição dentro dos padrões de normalidade, que apresentavam, ou não, o sintoma de zumbido, divididos em grupo zumbido e grupo controle. Foram pesquisados os limiares de reconhecimento de sentenças no ruído, por meio do teste Listas de Sentenças em Português. Resultados O grupo zumbido apresentou pior desempenho para os dois ruídos utilizados, porém, com diferença estatística somente na utilização do ruído speech-noise. Conclusão O desempenho de sujeitos com audição normal e queixa de zumbido, no reconhecimento de fala na presença de ruído competitivo, foi pior que em indivíduos sem o sintoma, principalmente na etapa com o ruído speech-noise.

Brazilian Portuguese Hearing in Noise Test (HINT): different interpretation criteria for individuals' responses.

The ability to recognize the sounds of speech enables an efficient communication. This ability must always be considered when communication disorders are evaluated. In this study, sentences of the Hearing in Noise Test (HINT), originally developed in English and adapted to Brazilian Portuguese, were used to evaluate speech recognition in silence and in the presence of noise. Although this test can be an important clinical tool, it is noticed that it has not been used in audiological clinical practice in Brazil. One possible reason is the lack of standardization of some aspects of the test, including the methods adopted to analyze the patient's answers. The aim of this study was to analyze different judgment criteria of individuals' answers during sentence recognition thresholds measurement using the HINT in Brazilian Portuguese. The study was conducted with 30 young adults (three groups of 10 people), between 18 and 25 years old, of both genders, with normal hearing. HINT sentences were adapted to Brazilian Portuguese and speech recognition thresholds were determined in the presence of noise by using three judgment criteria published in Brazilian literature. A single variation analysis was performed to compare the average threshold between the three groups. The maximum error probability to reject the null hypothesis was 5%. The mean and standard deviations of thresholds, respectively, were: 59.90 ± 1.43 dB SPL; 59.60 ± 0.53 dB SPL and 59.95 ± 0.6 dB SPL. There was no statistically significant difference between the means (F = 0.398; p> 0.05). Regardless the judging criteria used, results obtained in all groups were equivalent.