Bone-Anchored Hearing Devices for Single-Sided Deafness: A New Preoperative Evaluation Protocol and Widening of Indications Proposal.

INTRODUCTION: Bone-anchored hearing devices (BAHD) are well-known good solution for single-sided deafness (SSD). Despite power extension of recently introduced BAHD with implanted active transducer, with indications up to 65 dB Hl of bone conduction (BC) threshold on the implanted side, their indications for SSD still remain better than 25 dB on the good ear, with regards to bone conduction thresholds. The aim of this study was to assess the possibility to enlarge BAHD indications for SSD by means of a newly proposed candidacy evaluation protocol, which includes a new software-aided method. METHODS: 20 SSD patients (mean age 56 years, 9 females, and 11 males) were divided into two groups: group A (10 patients, BC <25 dB Hl on the hearing side) and group B (10 patients, BC between 25 and 35 dB Hl). Recipients were submitted to bisyllabic words speech audiometry in silence and to authors' newly proposed IFastSRT50 test by means of software which shift noise intensity of a single word list on the basis of correct recipient recognition responses. A sound speaker for signal (bisyllabic words) and noise (babble) was disposed at 1 m from the deaf side of the patient. An earphone covering only the good ear of the recipient was used in order to perform its air conduction masking with white noise. A BAHD test device was disposed on the mastoid of the deaf side. Both signal and masking intensities were set to 55 dB SPL in order to mask airway conduction on the good ear without masking its bone way interaural conduction from the BAHD tester. RESULTS: With BAHD tester turned off, no recognition was detected. Speech audiometry with BAHD tester turned on revealed mean values of 92% for group A and 89% for group B, with a difference of 3.0% (χ2 = 0.285 and p = 0.5935). As for IFastSRT50 with BAHD tester turned on, mean signal-to-noise ratio value to obtain 50% of recognition was -6.89 for group A and -6, with a difference of 0.89 (t = 1,201 and p = 0.2453). CONCLUSION: BAHD are confirmed to be a good solution for SSD cases. The absence of statistically significant differences in our two tested groups suggests that newer implanted active transducer device indications should be extended up to 35 dB Hl on the hearing ear. The IFastSRT50 is a reliable and quick method to enhance preoperative candidacy evaluation.

Discrimination of degrees of auditory performance from the digits-in-noise test based on hearing status.

OBJECTIVE: To discriminate among degrees of auditory performance of the Digits-in-Noise (DIN) test. DESIGN: We performed Pearson's correlations and age- and sex-adjusted linear regression models to examine the correlation between pure-tone average (PTA) from pure-tone audiometric tests and speech recognition thresholds (SRT) from the DIN test. Then, optimal SRT cut-points by PTA-defined hearing status (0-25 dB HL [normal], 26-40 dB HL [mild hearing loss], 41-50 dB HL [moderate hearing loss]) were compared across three methods: Youden, Nearest, and Liu. SRT-defined categories of auditory performance were compared to PTA-defined hearing categories to examine the convergence of similar categories. Study Sample: 3422 Rotterdam Study participants aged 51-98 years between 2011 and 2014. RESULTS: The correlation between SRT and PTA was 0.65 (95% Confidence Interval: 0.63, 0.67) in the overall sample. The variability of SRT explained by PTA after age and sex adjustment was 54%. Optimal cut-points for the overall sample across the three methods were: ≤ -5.55 dB SNR (normal); > -5.55 to ≤ -3.80 dB SNR (insufficient performance); > -3.80 dB SNR (poor performance). When comparing the SRT- or PTA-defined categories, 59.8% had concordant hearing categories and 40.2% had discordant hearing categories. CONCLUSIONS: Discrimination of degrees of auditory performance may add greater utility of the DIN test.

The effect of language, spatial factors, masker type and memory span on speech-in-noise thresholds in sequential bilingual children.

This study considers whether bilingual children listening in a second language are among those on which higher processing and cognitive demands are placed when noise is present. Forty-four Swedish sequential bilingual 15 year-olds were given memory span and vocabulary assessments in their first and second language (Swedish and English). First and second language speech reception thresholds (SRTs) at 50% intelligibility for numbers and colors presented in noise were obtained using an adaptive procedure. The target sentences were presented in simulated, virtual classroom acoustics, masked by either 16-talker multi-talker babble noise (MTBN) or speech shaped noise (SSN), positioned either directly in front of the listener (collocated with the target speech), or spatially separated from the target speech by 90° to either side. Main effects in the Spatial and Noise factors indicated that intelligibility was 3.8 dB lower in collocated conditions and 2.9 dB lower in MTBN conditions. SRTs were unexpectedly higher by 0.9 dB in second language conditions. Memory span significantly predicted 17% of the variance in the second language SRTs, and 9% of the variance in first language SRTs, indicating the possibility that the SRT task places higher cognitive demands when listening to second language speech than when the target is in the listener's first language.

An examination of speech reception thresholds measured in a simulated reverberant cafeteria environment.

OBJECTIVE: There is increasing demand in the hearing research community for the creation of laboratory environments that better simulate challenging real-world listening environments. The hope is that the use of such environments for testing will lead to more meaningful assessments of listening ability, and better predictions about the performance of hearing devices. Here we present one approach for simulating a complex acoustic environment in the laboratory, and investigate the effect of transplanting a speech test into such an environment. DESIGN: Speech reception thresholds were measured in a simulated reverberant cafeteria, and in a more typical anechoic laboratory environment containing background speech babble. STUDY SAMPLE: The participants were 46 listeners varying in age and hearing levels, including 25 hearing-aid wearers who were tested with and without their hearing aids. RESULTS: Reliable SRTs were obtained in the complex environment, but led to different estimates of performance and hearing-aid benefit from those measured in the standard environment. CONCLUSIONS: The findings provide a starting point for future efforts to increase the real-world relevance of laboratory-based speech tests.

Development of Digit in Noise Test in Hindi.

BACKGROUND: The digit in the noise test is a simple hearing screening tool that can identify hearing loss at the early stage. This screening tool takes less time than traditional pure-tone audiometry. There is a scarcity of hearing health professionals with few resources for carrying out hearing screening on a large scale in India. Hence, a hearing screening tool for the Hindi-speaking population is needed. AIM AND OBJECTIVE: The study aimed to develop and validate the Digit in Noise test in Hindi (DIN-H). METHODS: A native Hindi female speaker recorded single digits from 1 to 9 made into triplet combinations, which were binaurally presented to 20 normal hearing subjects having hearing thresholds less than 25 dBHL from 250 to 8000 Hz in the presence of broadband speech-shaped noise. The digit triplets were homogenized using speech intelligibility function for similar difficulty levels across stimuli. The homogenized stimuli were evaluated by obtaining the Speech Recognition Threshold (SRT) of 20 normal hearing subjects. RESULTS: The Mean SRT was - 10.4 and - 11.3 dB before and after homogenization. A strong positive correlation existed between test and retest SRTs (0.78). Mean SRT and slope obtained before and after optimization were comparable to other languages like Korean and English. This test can act as a reliable screening tool for assessing individuals. The test was administered to 106 normal hearing participants. The 95th percentile of the SRT value obtained was - 5.6 dB, which was kept as a cut-off score for the screening test. CONCLUSION: DIN-H can be used as a screening tool for assessing the integrity of the auditory system on a large scale in less time for the Hindi-speaking population.

Decreased Speech Comprehension and Increased Vocal Efforts Among Healthcare Providers Using N95 Mask.

AIM: N95 masks are recommended for the healthcare providers (HCPs) taking care of patients with coronavirus disease 2019. However, the use of these masks hampers communication. We aimed to evaluate the effect of N95 masks on speech comprehension among listeners and vocal efforts (VEs) of the HCPs. MATERIALS AND METHODS: This prospective study involved 50 HCPs. We used a single observer with normal hearing to assess the difficulty in comprehension, while VE was estimated in HCPs. The speech reception threshold (SRT), speech discrimination score (SDS), and VEs were evaluated initially without using N95 mask and then repeated with HCPs wearing N95 mask. RESULTS: The use of masks resulted in a statistically significant increase in mean SRT [4.25 (1.65) dB] and VE [2.6 (0.69)], with simultaneous decrease in mean SDS [19.2 (8.77)] (all p-values < 0.0001). Moreover, demographic parameters including age, sex, and profession were not associated with change in SRT, SDS, and VE (all p-values > 0.05). CONCLUSION: Though use of N95 masks protects the HCPs against the viral infection, it results in decreased speech comprehension and increased VEs. Moreover, these issues are universal among the HCPs and are applicable to the general public as well.

Relationship between electrode position and temporal modulation sensitivity in cochlear implant users: Are close electrodes always better?

Temporal modulation sensitivity has been studied extensively for cochlear implant (CI) users due to its strong correlation to speech recognition outcomes. Previous studies reported that temporal modulation detection thresholds (MDTs) vary across the tonotopic axis and attributed this variation to patchy neural survival. However, correlates of neural health identified in animal models depend on electrode position in humans. Nonetheless, the relationship between MDT and electrode location has not been explored. We tested 13 ears for the effect of distance on modulation sensitivity, specifically targeting the question of whether electrodes closer to the modiolus are universally beneficial. Participants in this study were postlingually deafened and users of Cochlear Nucleus CIs. The distance of each electrode from the medial wall (MW) of the cochlea and mid-modiolar axis (MMA) was measured from scans obtained using computerized tomography (CT) imaging. The distance measures were correlated with slopes of spatial tuning curves measured on selected electrodes to investigate if electrode position accounts, at least in part, for the width of neural excitation. In accordance with previous findings, electrode position explained 24% of the variance in slopes of the spatial tuning curves. All functioning electrodes were also measured for MDTs. Five ears showed a positive correlation between MDTs and at least one distance measure across the array; 6 ears showed negative correlations and the remaining two ears showed no relationship. The ears showing positive MDT-distance correlations, thus benefiting from electrodes being close to the neural elements, were those who performed better on the two speech recognition measures, i.e., speech reception thresholds (SRTs) and recognition of the AzBio sentences. These results could suggest that ears able to take advantage of the proximal placement of electrodes are likely to have better speech recognition outcomes. Previous histological studies of humans demonstrated that speech recognition is correlated with spiral ganglion cell counts. Alternatively, ears with good speech recognition outcomes may have good overall neural health, which is a precondition for close electrodes to produce spatially confined neural excitation patterns that facilitate modulation sensitivity. These findings suggest that the methods to reduce channel interaction, e.g., perimodiolar electrode array or current focusing, may only be beneficial for a subgroup of CI users. Additionally, it suggests that estimating neural survival preoperatively is important for choosing the most appropriate electrode array type (perimodiolar vs. lateral wall) for optimal implant function.

Hearing Loss and Cognition Among Older Adults in a Han Chinese Cohort.

Presbycusis (PC) is associated with cognitive decline and incident dementia. Speech reception thresholds (SRT) are used to assess speech detection, which points toward a central component of PC. However, to the best of our knowledge, no previous study has reported the relationship between SRT and cognitive function in older adults in a Han Chinese cohort. Therefore, in this study, we investigate the association of hearing loss, indexed using pure tone average (PTA) and SRT, with cognitive function in a Han Chinese cohort using a standardized neurocognitive battery. Subjects (aged ≥60 years) with no history of psychiatric or neurological diseases were recruited. All subjects underwent a battery of neuropsychological and auditory tests. According to the PTA of the better ear, the subjects were further divided into PC and normal PTA (NP) groups. Regression analyses were performed to examine the relationship between cognitive function and hearing loss in the PC and NP groups and all subjects when controlling for age, sex, education level, diabetes, smoking, and hypertension. Cognitive function was significantly associated with PTA and SRT in all subjects. In all subjects, the correlations between non-verbal cognitive scores and SRT were stronger than those between non-verbal cognitive scores and PTA, whereas the correlations between verbal cognitive scores and PTA were stronger than those between verbal cognitive scores and SRT. Moreover, the correlations between PTA or SRT and cognitive function in the PC group were in principle stronger than those in the NP group. Our findings indicate that cognitive function is significantly associated with PTA and SRT in older adults in a Han Chinese cohort. Therefore, SRT could be an important auditory test for exploring cognitive decline in PC and could complement PTA.

Modeling Sluggishness in Binaural Unmasking of Speech for Maskers With Time-Varying Interaural Phase Differences.

In studies investigating binaural processing in human listeners, relatively long and task-dependent time constants of a binaural window ranging from 10 ms to 250 ms have been observed. Such time constants are often thought to reflect "binaural sluggishness." In this study, the effect of binaural sluggishness on binaural unmasking of speech in stationary speech-shaped noise is investigated in 10 listeners with normal hearing. In order to design a masking signal with temporally varying binaural cues, the interaural phase difference of the noise was modulated sinusoidally with frequencies ranging from 0.25 Hz to 64 Hz. The lowest, that is the best, speech reception thresholds (SRTs) were observed for the lowest modulation frequency. SRTs increased with increasing modulation frequency up to 4 Hz. For higher modulation frequencies, SRTs remained constant in the range of 1 dB to 1.5 dB below the SRT determined in the diotic situation. The outcome of the experiment was simulated using a short-term binaural speech intelligibility model, which combines an equalization-cancellation (EC) model with the speech intelligibility index. This model segments the incoming signal into 23.2-ms time frames in order to predict release from masking in modulated noises. In order to predict the results from this study, the model required a further time constant applied to the EC mechanism representing binaural sluggishness. The best agreement with perceptual data was achieved using a temporal window of 200 ms in the EC mechanism.

Implicit Talker Training Improves Comprehension of Auditory Speech in Noise.

Previous studies have shown that listeners are better able to understand speech when they are familiar with the talker's voice. In most of these studies, talker familiarity was ensured by explicit voice training; that is, listeners learned to identify the familiar talkers. In the real world, however, the characteristics of familiar talkers are learned incidentally, through communication. The present study investigated whether speech comprehension benefits from implicit voice training; that is, through exposure to talkers' voices without listeners explicitly trying to identify them. During four training sessions, listeners heard short sentences containing a single verb (e.g., "he writes"), spoken by one talker. The sentences were mixed with noise, and listeners identified the verb within each sentence while their speech-reception thresholds (SRT) were measured. In a final test session, listeners performed the same task, but this time they heard different sentences spoken by the familiar talker and three unfamiliar talkers. Familiar and unfamiliar talkers were counterbalanced across listeners. Half of the listeners performed a test session in which the four talkers were presented in separate blocks (blocked paradigm). For the other half, talkers varied randomly from trial to trial (interleaved paradigm). The results showed that listeners had lower SRT when the speech was produced by the familiar talker than the unfamiliar talkers. The type of talker presentation (blocked vs. interleaved) had no effect on this familiarity benefit. These findings suggest that listeners implicitly learn talker-specific information during a speech-comprehension task, and exploit this information to improve the comprehension of novel speech material from familiar talkers.

Binaural Glimpses at the Cocktail Party?

Humans often have to focus on a single target sound while ignoring competing maskers in everyday situations. In such conditions, speech intelligibility (SI) is improved when a target speaker is spatially separated from a masker (spatial release from making, SRM) compared to situations where both are co-located. Such asymmetric spatial configurations lead to a 'better-ear effect' with improved signal-to-noise ratio (SNR) at one ear. However, maskers often surround the listener leading to more symmetric configurations where better-ear effects are absent in a long-term, wideband sense. Nevertheless, better-ear glimpses distributed across time and frequency persist and were suggested to account for SRM (Brungart and Iyer 2012). Here, speech reception was assessed using symmetric masker configurations while varying the spatio-temporal distribution of potential better-ear glimpses. Listeners were presented with a frontal target and eight single-talker maskers in four different symmetrical spatial configurations. Compared to the reference condition with co-located target and maskers, an SRM of up to 6 dB was observed. The SRM persisted when the frequency range of the maskers above or below 1500 Hz was replaced with stationary speech-shaped noise. Comparison to a recent short-time binaural SI model showed that better-ear glimpses can account for half the observed SRM, while binaural interaction utilizing phase differences is required to explain the other half.

Changes in children's speech discrimination and spatial release from masking between 2 and 4 years after sequential cochlear implantation.

OBJECTIVE: To document changes in speech reception thresholds (SRTs) and spatial release from masking (SRM) for sequentially implanted children at 2 and 4 years after they received their second cochlear implant (CI2). METHODS: Participants were 17 children who consistently used two sequentially implanted and optimally programmed CIs. SRTs were measured monaurally in quiet and binaurally in noise using the adaptive McCormick toy discrimination test. Speech signals were presented from 0° azimuth and noise from 0°, +90° or  -90° azimuth. SRM was calculated from SRTs in noise. Measurements were made at 2 and 4 year post-CI2. RESULTS: There were significant improvements over time in SRTs in quiet, SRTs in noise and SRM. SRTs in quiet improved more for CI2 than for the first implant (CI1). SRTs in noise and SRM improved more when noise was presented closest to CI1 than when closest to CI2. Performance became more symmetrical over time. DISCUSSION: Despite prolonged periods of unilateral auditory deprivation sequentially implanted children exhibited continued improvement in SRT and SRM. These results are valuable in setting expectations for and counselling families of children considering sequential CIs.

Steroid-based treatments for patients with total sudden sensorineural hearing loss.

CONCLUSIONS: In patients with total sudden sensorineural hearing loss (SSNHL), oral prednisone (OP) alone or intratympanic dexamethasone (ITD) alone have comparable results. The addition of salvage ITD following OP does not seem to add over either single modality treatment. OBJECTIVES: To study the effect of steroid-based treatments in patients with total SSNHL. METHODS: The medical charts of 59 patients with total loss of hearing, defined as pure tone thresholds in the profound range (> 90 dB) with an unobtainable speech reception threshold (SRT) that were treated with OP (n = 20), ITD (n = 13), or OP followed by salvage ITD (n = 26) were analyzed. Response to treatment was evaluated by means of pure tone thresholds, SRT, and speech discrimination score (SDS), immediately after treatment and on a follow-up visit. RESULTS: Forty-nine patients (83%) responded to treatment, with mean significant improvements of 36, 34, 31, and 25 dB at 500, 1000, 2000, and 4000 Hz, respectively. The mean improvement in SRT was 33 dB, and SDS improved by 32%. There were no differences in improvement in pure tone thresholds and SRT among the three treatment groups. The late effect of OP was similar to the effect of salvage ITD.