Normal-hearing Ears Research Articles

Wideband tympanometry in otitis Media

BackgroundOtitis media with effusion (OME) is one of the most frequent infectious diseases in children and is the most common cause of acquired hearing loss in childhood. Diagnosis of OME is mainly dependent on the single-frequency tympanometry. Wideband tympanometry (WBT) is an emerging technology that has been utilized to overcome the limitations of conventional tympanometric procedures. This study aimed to evaluate the diagnostic value of wideband acoustic absorbance in children suffering from otitis media.MethodsThis study included a control group of 50 children with 100 ears with bilateral normal peripheral hearing and bilateral normal middle ear function and a study group which included 100 children with 176 ears complaining of otitis media. Measures included subjects history, basic audiological evaluation and wideband tympanometry. Resonant frequency, tympanometric peak pressure and middle ear absorbance were measured from wideband tympanometry and compared in both groups.ResultsThere was a statistically significant reduction of resonsnce frequency in the study group in comparison to the control group. Also, there was a statistically significant reduction of tympanometric peak pressure in the study group in comparison to the control group. As regards the absorbance, there was a statistically significant reduction of absorbance in the study group in comparison to the control group at all tested frequencies (250Hz- 8000Hz). The best area under the receiver operating characteristic curve values for diagnosing OM were obtained at all tested frequencies. Data of this work showed that higher values were mainly at 250Hz, 500Hz and 1kHz (0.84, 0.88 and 0.93 respectively).ConclusionFindings of this study suggested that wide band tympanometry can be used efficiently in various degrees of OM.

Perception of voice cues and speech-in-speech by children with prelingual single-sided deafness and a cochlear implant

Voice cues, such as fundamental frequency (F0) and vocal tract length (VTL), help listeners identify the speaker's gender, perceive the linguistic and emotional prosody, and segregate competing talkers. Postlingually implanted adult cochlear implant (CI) users seem to have difficulty in perceiving and making use of voice cues, especially of VTL. Early implanted child CI users, in contrast, perceive and make use of both voice cues better than CI adults, and in patterns similar to their peers with normal hearing (NH).In our study, we investigated the perception and use of voice cues in children with single-sided deafness (SSD) who received their CI at an early age (SSD+CI), in an attempt to bridge the gap between these two groups. The SSD+CI children have access to bilateral auditory information and often receive their CI at an early age, similar to CI children. They may also have dominant acoustic representations, similar to CI adults who acquired hearing loss at a later age. As such, the current study aimed to investigate the perception and use of voice cues by a group of nine early-implanted children with prelingual SSD. The study consisted of three experiments: F0 and VTL discrimination, voice gender categorization, and speech-in-speech perception. In each experiment, the results of the SSD group are compared to children and adults with CIs (for their CI ear) and with typical hearing (for their NH ear).Overall, the SSD+CI children had poorer VTL detection thresholds with their CI compared to their NH ear, while their F0 perception was similar across ears. Detection thresholds for both F0 and VTL with their CI ear was comparable to those of bilaterally implanted CI children, suggesting that SSD+CI children do not only rely on their NH ear, but actually make use of their CI. SSD+CI children relied more heavily on F0 cues than on VTL cues for voice gender categorization, with cue weighting patterns comparable to those of CI adults. In contrast to CI children, the SSD+CI children showed limited speech perception benefit based on F0 and VTL differences between the target and masker speaker, which again corresponded to the results of CI adults. Altogether, the SSD+CI children make good use of their CI, despite a good-hearing ear, however, the perceptual patterns seem to fall in-between those of CI children and CI adults. Perhaps a combination of childhood neuroplasticity, limited experience with relying only on the CI, and a dominant acoustic representation of voice gender explain these results.

Study of word-in-noise perception scores at saccular acoustic sensitivity level: randomized clinical trial

BackgroundIn humans, saccular acoustic sensitivity has been confirmed. The aim of this study was to determine the scores of the word-in-noise perception test at the saccular acoustic sensitivity level.MethodologyIn this randomized clinical trial study, 101 participants in the age group of 14 to 25 years with normal hearing and middle ear function, detectable vestibular evoked myogenic potentials (VEMP), normal states of mental health, and night sleep were investigated. The scores of word-in-noise perception and word-in-noise discrimination tests were evaluated for each person at two intensity levels, most comfortable level (MCL) and saccular acoustic sensitivity. Mann-Whitney was used for the multiple comparisons.ResultsThere was a significant difference between the scores of the word-in-noise perception test at MCL and saccular acoustic sensitivity (U = 3971.50, Z = − 2.10, p’ = 0.04), and also between the scores of the word-in-noise discrimination test at the MCL compared to saccular acoustic sensitivity (U = 399.89, Z = − 2.49, p’ = 0.04). Word-in-noise discrimination scores in MCL (U = 3484.00, Z = -3.72, p’ = 0.00) and saccular acoustic sensitivity (U = 705.50, Z = − 3.78, p’ = 0.00) were higher than word-in-noise perception.ConclusionsWord-in-noise perception and word-in-noise discrimination scores are higher in saccular acoustic sensitivity level than MCL, suggesting that the vestibular system participates in loud speech perception. Also, in people with normal hearing thresholds, word-in-noise perception scores will be lower than word-in-noise discrimination scores for both loud and common intensity levels.

Localization and Speech-in-Noise Performance in a Virtual Reality Test Environment: A Pilot Study of Adults With Single-Sided Deafness Using a Cochlear Implant.

The purpose of this exploratory study was to (a) construct a virtual reality (VR) test environment to measure speech recognition in noise (SIN) and localization, and (b) use the VR test environment to establish degree of binaural hearing benefit among a small number of adults with single-sided deafness (SSD) using a cochlear implant (CI). This pilot study included five adults implanted for SSD. The test environment was composed of an eight-speaker array that delivered restaurant noise and Institute of Electrical and Electronics Engineers sentences. VR head-mounted display goggles delivered a video recording of a busy restaurant. Participants completed SIN and localization in two conditions: (a) normal-hearing ear and a CI on the contralateral SSD side (CI-ON) and (b) normal-hearing ear and unaided on the contralateral SSD side (CI-OFF). Overall, CI benefits for SIN and localization within the VR test environment were improved for some participants, although not all. CI benefit for SIN and localization was dependent on speaker location. VR test environments present new opportunities for studying SIN and localization abilities in participants with CIs. This pilot study shows that, within a VR test environment, degree of CI benefit among SSD participants for SIN and localization varies across speaker location and across participants.

Parent-Reported Ease of Listening in Preschool-Aged Children With Bilateral and Unilateral Hearing Loss.

Evidence from school-aged children suggests that the ease with which children listen varies with the presence of hearing loss and the acoustic environment despite the use of devices like hearing aids. However, little is known about the ease of listening in preschool-aged children with hearing loss-an age at which rapid learning occurs and increased listening difficulty or effort may diminish the required capacity to learn new skills. To this end, the objectives of the present study were to (i) assess parent-reported aided ease of listening as a function of hearing loss configuration (hearing loss in one versus both ears) and device configuration among children with hearing loss in one ear (unilateral hearing loss), and (ii) investigate factors that influence children's ease of listening. Parents of 83 children with normal hearing, 54 aided children with bilateral hearing loss (hearing loss in both ears), and 139 children with unilateral hearing loss participated in the study. Of the 139 children with unilateral loss, 72 were unaided, 54 were aided with a device on the ear with hearing loss (direct aiding) and 13 were aided with a device that routed signals to the contralateral normal hearing ear (indirect aiding). Mean age of children was 40.2 months (1 SD = 2.5; range: 36 to 51). Parents completed the two subscales of the Parents' Evaluation of Aural/Oral Performance of Children+ (PEACH+) questionnaire, namely functional listening and ease of listening. Individual percent scores were computed for quiet and noisy situations. Linear mixed-effects models were used to assess the effect of hearing loss configuration and device configuration in children with unilateral hearing loss. Multiple regression was used to assess factors that influenced ease of listening. Factors included hearing thresholds, age at first device fit, consistency in device use, condition (quiet/noise), presence of developmental disabilities, and functional listening abilities. Children with direct aiding for their hearing loss, either unilateral or bilateral, had similarly lower functional listening skills and ease of listening than their normal hearing peers. Unaided children with unilateral hearing loss had lower functional listening skills and ease of listening than their normal hearing peers in noise but not in quiet. All aided children with unilateral hearing loss, irrespective of direct or indirect aiding had lower functional listening skills and ease of listening relative to normal hearing children in both quiet and noise. Furthermore, relative to unaided children with unilateral hearing loss, those with indirect aiding had lower functional listening and ease of listening. Regression analyses revealed functional listening as a significant predictor of ease of listening in all children with hearing loss. In addition, worse degrees of hearing loss and presence of noise reduced ease of listening in unaided children with unilateral hearing loss. Bilateral hearing loss is associated with poorer-than-typical ease of listening in preschoolers even when aided. The impact of unilateral hearing loss on ease of listening is similar to that observed in children with bilateral hearing loss, despite good hearing in one ear and aiding. Given increased difficulties experienced by children with unilateral loss, with or without a device, additional strategies to facilitate communication abilities in noise should be a priority.

Biomarkers of auditory cortical plasticity and development of binaural pathways in children with unilateral hearing loss using a hearing aid

Congenital or early-onset unilateral hearing loss (UHL) can disrupt the normal development of the auditory system. In extreme cases of UHL (i.e., single sided deafness), consistent cochlear implant use during sensitive periods resulted in cortical reorganization that partially reversed the detrimental effects of unilateral sensory deprivation. There is a gap in knowledge, however, regarding cortical plasticity i.e. the brain's capacity to adapt, reorganize, and develop binaural pathways in milder degrees of UHL rehabilitated by a hearing aid (HA). The current study was set to investigate early-stage cortical processing and electrophysiological manifestations of binaural processing by means of cortical auditory evoked potentials (CAEPs) to speech sounds, in children with moderate to severe-to-profound UHL using a HA. Fourteen children with UHL (CHwUHL), 6-14 years old consistently using a HA for 3.5 (±2.3) years participated in the study. CAEPs were elicited to the speech sounds /m/, /g/, and /t/ in three listening conditions: monaural [Normal hearing (NH), HA], and bilateral [BI (NH + HA)]. Results indicated age-appropriate CAEP morphology in the NH and BI listening conditions in all children. In the HA listening condition: (1) CAEPs showed similar morphology to that found in the NH listening condition, however, the mature morphology observed in older children in the NH listening condition was not evident; (2) P1 was elicited in all but two children with severe-to-profound hearing loss, to at least one speech stimuli, indicating effective audibility; (3) A significant mismatch in timing and synchrony between the NH and HA ear was found; (4) P1 was sensitive to the acoustic features of the eliciting stimulus and to the amplification characteristics of the HA. Finally, a cortical binaural interaction component (BIC) was derived in most children. In conclusion, the current study provides first-time evidence for cortical plasticity and partial reversal of the detrimental effects of moderate to severe-to-profound UHL rehabilitated by a HA. The derivation of a cortical biomarker of binaural processing implies that functional binaural pathways can develop when sufficient auditory input is provided to the affected ear. CAEPs may thus serve as a clinical tool for assessing, monitoring, and managing CHwUHL using a HA.

Comparison of vestibular function in hereditary hearing loss patients with GJB2, CDH23, and SLC26A4 variants

To investigate the association between hereditary hearing loss and vestibular function, we compared vestibular function and symptoms among patients with GJB2, SLC26A4, and CDH23 variants. Thirty-nine patients with sensory neural hearing loss (11 males and 28 females) with biallelic pathogenic variants in either GJB2, SLC26A4, or CDH23 were included in this study (13 GJB2, 15 SLC26A4, and 11 CDH23). The patients were examined using caloric testing and cervical and ocular vestibular-evoked myogenic potentials (cVEMP and oVEMP). We also compared vestibular function and symptoms between patients with these gene variants and 78 normal-hearing ears without vestibular symptoms as controls. The frequency of semicircular canal hypofunction in caloric testing was higher in patients with SLC26A4 variants (47%) than in those with GJB2 (0%) and CDH23 variants (27%). According to the cVEMP results, 69% of patients with GJB2 variants had saccular hypofunction, a significantly higher proportion than in those carrying other variants (SLC26A4, 20%; CDH23, 18%). In oVEMP, which reflects utricular function, no difference was observed in the frequency of hypofunction among the three genes (GJB2, 15%; SLC26A4, 40%; and CDH23, 36%). Hence, discernable trends indicate vestibular dysfunction associated with each gene.

Detection of Reduced Diameter of the Cochlear Nerve in Long-term Deaf Patients Quantified With Semiautomatic Measurement of Nerve Cross-sectional Area Using 3T MRI Data.

High-resolution parallel transmit T2 sampling perfection with application optimized contrast using different flip angle evolution sequence with improved edge discrimination and semiautomatic determination of nerve cross-sectional area (CSA) can be used to evaluate nerve degeneration in the inner auditory canal (IAC) in long-term deaf patients. In patients with hearing loss, temporal bone MRI is routinely acquired to evaluate the morphology of the nerves within the IAC. Earlier studies have shown that the diameter of the cochlear nerve can be used as prognostic marker for the auditory performance after cochlear implantation in postlingually deaf patients. Eighty-two consecutive MRI scans were analyzed using a semiautomatic tool to measure CSA of cranial nerves in the IAC. Results were correlated with patient history and audiology testing as well as with age and gender. There was a significant reduced CSA of the cochlear nerve in ears with moderate-to-profound hearing loss and deafness compared with ears with normal hearing, but no significant difference in ears with mild-to-moderate hearing loss compared with normal hearing. In detail, normal hearing ears had a CSA of 1.23 ± 0.11 mm2, whereas ears with pantonal hearing loss of more than 40 dB had 1.02 ± 0.05 mm2 (P = 0.026). Maximal CSA of the facial nerve was not different among all groups (average, 1.04 mm2 ± 0.03; linear regression, P = 0.001) and stable with age. However, vestibular nerve CSA decreased significantly with age (average, 1.78 ± 0.05 mm2; linear regression, P = 0.128). In long-term deaf patients, smaller the diameter of cochlear nerve is the more severe the hearing loss is. The new semiautomatic tool can primarily be used to assess nerve diameter and possibly determine ears with nerve degeneration.

Auditory Cortical Plasticity in Patients with Single-Sided Deafness Before and After Cochlear Implantation

PurposeThis study investigated neuroplastic changes induced by postlingual single-sided deafness (SSD) and the effects of a cochlear implantation for the deaf ear. Neural processing of acoustic signals from the normal hearing ear to the brain was studied before and after implantation using a positron emission tomography (PET)/CT scanner.MethodsEight patients with postlingual SSD received a cochlear implant (CI) in a prospective clinical trial. Dynamic imaging was performed in a PET/CT scanner using radioactively labeled water ([15O]H2O) to localize changes in the regional cerebral blood flow (rCBF) with and without an auditory task of logatomes containing speech-like elements without meaningful context. The normal hearing ear was stimulated before implantation and after the use of the cochlear implant for at least 8 months (mean 13.5, range 8.1–26.6). Eight age- and gender-matched subjects with normal hearing on both sides served as healthy control subjects (HCS).ResultsWhen the normal hearing ear of SSD patients was stimulated before CI implantation, the [15O]H2O-PET showed a more symmetrical rCBF in the auditory regions of both hemispheres in comparison to the HCS. The use of CI increased the asymmetry index (AI) in six of eight patients indicating an increase of activity of the contralateral hemisphere. Non-parametric statistics revealed a significant difference in the AI between patients before CI implantation and HCS (p < .01), which disappeared after CI implantation (p = .195).ConclusionThe functional neuroimaging data showed a tendency towards normalization of neuronal activity after CI implantation, which supports the effectiveness of CI in SSD patients.Trial RegistrationClinicalTrials.gov Identifier: NCT01749592, December 13, 2012.

Effects of Auditory Training on Speech Recognition in Children with Single-Sided Deafness and Cochlea Implants Using a Direct Streaming Device: A Pilot Study.

Treating individuals with single-sided deafness (SSD) with a cochlear implant (CI) offers significant benefits for speech perception in complex spatial listening environments. After implantation, training without involvement of the normal-hearing ear is essential. Therefore, the AudioLink streaming device (MED-EL GmbH, Austria) can be used to connect the externally worn audio processor to media devices; thus, the auditory stimuli are directly streamed to the implanted ear. The aim was to test whether children with SSD, aged 5-12 years, accept this training method and whether auditory training, streamed directly via AudioLink using the Tiptoi device (Ravensburger GmbH., Ravensburg, Germany), improves speech recognition. A total of 12 children with SSD and implanted with a CI received Tiptoi training via AudioLink and were asked to practice daily for 10 min over a period of one month. All participants completed the training. The measurements employed to assess improvement included speech audiometry, speech, spatial, and quality of hearing scale for parents (SSQ P), and specially designed tasks crafted for this study. Daily training of 9.93 min was reported. The word recognition score (WRS) at 65 dB and 80 dB in aided condition significantly improved and the WRS streamed via AudioLink was significantly better after training. The speech, spatial, and qualities of hearing scale for parents (SSQ P questionnaire) showed significant improvement in the dimension of quality of hearing and overall gain. The outcomes of the Tiptoi tasks resulted in a significant benefit in both categories of the "recognition of sounds" and "understanding of sentences". The results are very encouraging and do not only show the positive uptake of daily training at home but also how this resulted in a significant improvement in subjective and objective measures for this rather short training period of one month only.

Cochlear implantation in unilateral hearing loss: impact of short- to medium-term auditory deprivation.

Single sided deafness (SSD) results in profound cortical reorganization that presents clinically with a significant impact on sound localization and speech comprehension. Cochlear implantation (CI) has been approved for two manufacturers' devices in the United States to restore bilateral function in SSD patients with up to 10 years of auditory deprivation. However, there is great variability in auditory performance and it remains unclear how auditory deprivation affects CI benefits within this 10-year window. This prospective study explores how measured auditory performance relates to real-world experience and device use in a cohort of SSD-CI subjects who have between 0 and 10 years of auditory deprivation. Subjects were assessed before implantation and 3-, 6-, and 12-months post-CI activation via Consonant-Nucleus-Consonant (CNC) word recognition and Arizona Biomedical Institute (AzBio) sentence recognition in varying spatial speech and noise presentations that simulate head shadow, squelch, and summation effects (S0N0, SSSDNNH, SNHNSSD; 0 = front, SSD = impacted ear, NH = normal hearing ear). Patient-centered assessments were performed using Tinnitus Handicap Inventory (THI), Spatial Hearing Questionnaire (SHQ), and Health Utility Index Mark 3 (HUI3). Device use data was acquired from manufacturer software. Further subgroup analysis was performed on data stratified by <5 years and 5-10 years duration of deafness. In the SSD ear, median (IQR) CNC word scores pre-implant and at 3-, 6-, and 12-months post-implant were 0% (0-0%), 24% (8-44%), 28% (4-44%), and 18% (7-33%), respectively. At 6 months post-activation, AzBio scores in S0N0 and SSSDNNH configurations (n = 25) demonstrated statistically significant increases in performance by 5% (p = 0.03) and 20% (p = 0.005), respectively. The median HUI3 score was 0.56 pre-implant, lower than scores for common conditions such as anxiety (0.68) and diabetes (0.77), and comparable to stroke (0.58). Scores improved to 0.83 (0.71-0.91) by 3 months post-activation. These audiologic and subjective benefits were observed even in patients with longer durations of deafness. By merging CI-associated changes in objective and patient-centered measures of auditory function, our findings implicate central mechanisms of auditory compensation and adaptation critical in auditory performance after SSD-CI and quantify the extent to which they affect the real-world experience reported by individuals.

Efferent involvement in neural adaptation to acoustical stimuli: Insights from otoacoustic emissions

Neural adaptation to sound level statistics has been demonstrated at various levels of the auditory pathway, including the auditory periphery. Adaptation is thought to improve the efficiency of encoding acoustic stimuli using limited neural resources without compromising accuracy. However, the precise mechanisms underlying the statistical learning of an acoustic environment are not fully understood. This includes the potential contribution to the stimulus-specific modulation of afferent auditory nerve activity by the medial olivocochlear reflex (MOCR), an efferent feedback loop linking the brainstem to the cochlear amplifier. We used otoacoustic emissions (OAEs) to investigate evidence of neural adaptation in the MOCR in response to broadband elicitors of fluctuating intensity whose mean levels were either predictable (alternating low [48 dB SPL] and high [66 dB SPL]) or unpredictable (randomly occurring low and high mean levels). Magnitudes and time-courses of the MOCR obtained in normal-hearing ears were compared for differences based on the presence or absence of an acoustically predictable context. Our findings will provide valuable insights into the role of the efferent auditory system in neural adaptation to acoustical stimuli at the auditory periphery.

Influence of overtones and undertones on melody recognition with a cochlear implant with SSD

Many cochlear implant (CI) users have difficulties recognising pitches and melodies because pitch transmission is blurred and shifted. This study investigates whether postlingually deafened adult CI users recognize melodies better when overtones are removed or undertones are added.Fifteen unilaterally postlingually deafened CI users (single sided deafness = SSD) were included aged 22 to 73 years (MW 52, SD 11.6) with CI hearing experience between 3 and 75 months (MW 33, SD 21.0) with varying MED-EL devices. Three short piano melodies were presented to them firstly to the normal-hearing ear and then in modified overtone or undertone variants and the original variant to the CI ear. These variants should be identified as one of the three original melodies. In addition, musical experience and ability were assessed by the Munich Music Questionnaire and the MiniPROMS music tests.The CI users showed the best melody recognition in the fundamental frequency variant. The overtone variant with the third overtone was as good as the original variant with all overtones with regard to melody recognition (p=1). However, the undertone variant with the first undertone was recognised significantly worse than the fundamental version (p=0.032). Furthermore, there was no correlation between musical experience or musical ability and the number of melodies recognised (p>0.1).Since a reduction of overtones did not worsen the melody recognition, overtone reduction should be considered in future music processing programs for the CI. This could reduce the energy consumption of the CI.

A Clinically Viable Medial Olivocochlear Reflex Assay Using Transient-Evoked Otoacoustic Emissions.

The contralateral medial olivocochlear reflex (MOCR) strength may indicate various auditory conditions in humans, but a clinically viable assay and equipment are needed for quick, accurate, and reliable measurements. The first experiment compared an earlier version of the assay, which used a nonlinear-mode chirp stimulus, with a new assay using a linear-mode click stimulus, designed to give reliable MOCR measurements in most normal-hearing ears. The second experiment extended the improved assay on a purpose-built binaural hardware platform that used forward-pressure level (FPL) calibration for both the stimulus and the contralateral MOCR elicitor. Transient-evoked otoacoustic emission (TEOAE) tests were measured with and without a 60-dB SPL MOCR-evoking contralateral broadband noise. The normalized MOCR strength (MOCR%) was derived from the TEOAE responses for each trial pair using the complex pressure difference weighted by the TEOAE magnitude. Experiment 1 compared MOCR% within-subject and across-day using two TEOAE stimuli: nonlinear-mode chirps (50 dB SPL, bandpass 1-5 kHz, 14 ms window delayed by 2 ms) and linear-mode clicks (50 dB SPL, bandpass 0.5-2.5 kHz, 13 ms window delayed by 5 ms). TEOAE responses were analyzed in the 0.5 to 2.5 kHz band. Thirty adult participants with normal hearing (30 ears) completed the study. The TEOAE stimulus was calibrated in situ using spectral flattening, and the contralateral noise was calibrated in a coupler. Twelve TEOAE trial pairs were collected for each participant and condition. Experiment 2 used a purpose-built binaural system. The TEOAE stimuli were linear-mode clicks (50 dB SPL, bandpass 1-3 kHz, 13 ms window delayed by 5 ms), analyzed in the 1 to 3 kHz band over ~12 trial pairs. After a probe refit, an additional trial pair was collected for the two early-stopping signal-to-noise ratio criteria (15 and 20 dB). They were evaluated for single-trial reliability and test time. Nineteen adult participants with normal hearing (38 ears) completed the study. The TEOAE clicks and contralateral elicitor noise were calibrated in situ using FPL and delivered with automated timing. MOCR% for linear-mode clicks was distinguishable from measurement variability in 98% to 100% of participants' ears (both experiments), compared with only 73% for the nonlinear-mode chirp (experiment 1). MOCR detectability was assessed using the MOCR% across-subject/within-subject variance ratio. The ratio in experiment 1 for linear-mode clicks was higher (8.0) than for nonlinear-mode chirps (6.4). The ratio for linear-mode clicks (8.9) in experiment 2 was slightly higher than for the comparable linear-mode stimulus (8.0) in experiment 1. TEOAEs showed excellent reliability with high signal-to-noise ratios in both experiments, but reliability was higher for linear-mode clicks than nonlinear-mode chirps. MOCR reliability for the two stimuli was comparable. The FPL pressure response retest reliability derived from the SPL at the microphone was higher than the SPL retest reliability across 0.4 to 8 kHz. Stable results required 2 to 3 trial pairs for the linear-mode click (experiments 1 and 2) and three for the nonlinear-mode chirp (experiment 1), taking around 2 min on average. The linear-mode click assay produced measurable, reliable, and stable TEOAE and MOCR results on both hardware platforms in around 2 min per ear. The stimulus design and response window ensured that any stimulus artifact in linear mode was unlikely to confound the results. The refined assay is ready to produce high-quality data quickly for clinical and field studies to develop population norms, recognize diagnostic patterns, and determine risk profiles.

Feasibility of Speech Testing Using Wireless Connection in Single-Sided Cochlear Implant Users.

The speech tests used to evaluate language performance in patients with bilateral deafness (BiD) and cochlear implant (CI) are problematic if applied to patients with single-sided deafness (SSD) because normal ear hearing should be excluded. Thus, we investigated the feasibility of using wireless connection to evaluate speech intelligibility of the CI ear in patients with SSD. Subjects and. Patients with BiD and SSD were administered the word recognition scores (WRS) and speech intelligibility tests using an iPadbased wireless connection and conventional methods. To exclude normal side hearing in patients with SSD, masking noise and "plugged and muffed" method were used in the WRS and speech intelligibility tests, respectively. In patients with BiD, the WRS and speech intelligibility tests results using wireless connection and conventional methods were similar. In patients with SSD, the WRS using masking noise in the normal hearing ear was similar to that of using wireless connection. However, 3 of 11 patients with SSD showed under-masked results if using the "plugged and muffed" method. Speech intelligibility testing using wireless connection is a convenient and reliable method for evaluating CI performance in patients with SSD. The "plugged and muffed" method is not recommended for evaluating CI performance in patients with SSD.

Factors that influence outcomes and device use for pediatric cochlear implant recipients with unilateral hearing loss.

Candidacy criteria for cochlear implantation in the United States has expanded to include children with single-sided deafness (SSD) who are at least 5 years of age. Pediatric cochlear implant (CI) users with SSD experience improved speech recognition with increased daily device use. There are few studies that report the hearing hour percentage (HHP) or the incidence of non-use for pediatric CI recipients with SSD. The aim of this study was to investigate factors that impact outcomes in children with SSD who use CIs. A secondary aim was to identify factors that impact daily device use in this population. A clinical database query revealed 97 pediatric CI recipients with SSD who underwent implantation between 2014 and 2022 and had records of datalogs. The clinical test battery included speech recognition assessment for CNC words with the CI-alone and BKB-SIN with the CI plus the normal-hearing ear (combined condition). The target and masker for the BKB-SIN were presented in collocated and spatially separated conditions to evaluate spatial release from masking (SRM). Linear mixed-effects models evaluated the influence of time since activation, duration of deafness, HHP, and age at activation on performance (CNC and SRM). A separate linear mixed-effects model evaluated the main effects of age at testing, time since activation, duration of deafness, and onset of deafness (stable, progressive, or sudden) on HHP. Longer time since activation, shorter duration of deafness, and higher HHP were significantly correlated with better CNC word scores. Younger age at device activation was not found to be a significant predictor of CNC outcomes. There was a significant relationship between HHP and SRM, with children who had higher HHP experiencing greater SRM. There was a significant negative correlation between time since activation and age at test with HHP. Children with sudden hearing loss had a higher HHP than children with progressive and congenital hearing losses. The present data presented here do not support a cut-off age or duration of deafness for pediatric cochlear implantation in cases of SSD. Instead, they expand on our understanding of the benefits of CI use in this population by reviewing the factors that influence outcomes in this growing patient population. Higher HHP, or greater percentage of time spent each day using bilateral input, was associated with better outcomes in the CI-alone and in the combined condition. Younger children and those within the first months of use had higher HHP. Clinicians should discuss these factors and how they may influence CI outcomes with potential candidates with SSD and their families. Ongoing work is investigating the long-term outcomes in this patient population, including whether increasing HHP after a period of limited CI use results in improved outcomes.

Matching the pitch perception of the cochlear implanted ear with the contralateral ear in patients with single-sided deafness: a novel approach.

Single-sided deaf patients following cochlear implantation often compare the sound quality of their implanted ear with normal hearing. The interaural differences can result in dissatisfaction with speech comprehension and reduced time of usage of the speech processor; hence, prolonging auditory adaptation time. The proposed calibration method presented in this study demonstrates how the frequency distribution of the cochlear implant can be set to adequately approximate the pitch perception of the contralateral normal hearing ear towards improving speech intelligibility in a noisy environment. In 12 postlingual single-sided deaf patients, subjective interaural pitch-matching was carried out to determine new central frequencies for the reallocation of the frequency bands of their speech processor (CP910, CP950 or CP1000, Cochlear, Australia). The patients were asked to compare the pitch of the tones presented to their normal hearing ear to the pitch of individual channels of their cochlear implant (CI522 or CI622, Cochlear, Australia). A third-degree polynomial curve was fit to the acquired matching frequencies to create the new frequency allocation table. Audiological measurements (free-field aided thresholds, speech reception thresholds, and monosyllabic word recognition score) in noise, together with a Speech, Spatial and Qualities of Hearing Scale (SSQ12) questionnaire (short version of the original SSQ) results were evaluated prior to the pitch-matching procedure, and again, 2 weeks later. The free-field aided thresholds of the patients showed no greater shift than ± 5dB following the procedure; however, their monosyllabic word recognition score in noise improved significantly (mean - 9.58%, SD 4.98%, matched pairs t test comparison: p < 0.001). The results of the SSQ12 questionnaire also showed significant improvement in speech intelligibility, sound localization, and sound quality (mean 0.96 points, SD 0.45 points, matched pairs t test comparison: p < 0.001). Matching the pitch perception of the implanted cochlea with the sensation of the normal hearing contralateral ear, resulted in significant changes in the quality of hearing in patients with single-sided deafness. It is plausible the procedure can usher positive results in bimodal patients or following sequential bilateral cochlear implantation.

Validity and reliability of integrated pressure level real-ear-to-coupler difference measurements

Objectives (1) To validate the measurement of foam-tip real-ear-to-coupler differences (wRECD) using an integrated pressure level (IPL) method and (2) to compare the reliability of this method to SPL-based measurement of the wRECD. Design SPL-based wRECD and the proposed IPL wRECD measurement were completed bilaterally. Test-retest reliability of IPL wRECD was determined with full re-insertion into the ear canal and compared to published SPL wRECD test-retest data. Study sample 22 adults with normal hearing and middle ear status were recruited. Results Differences between SPL-based wRECD and IPL wRECD measurements were within 1.51 dB on average below 5000 Hz. At and above 5000 Hz, IPL wRECD exceeded SPL wRECDs by 6.11 dB on average. The average test-retest difference for IPL wRECD across all assessed frequencies was 0.75 dB with the greatest improvements in reliability found below 750 Hz and above 3000 Hz. Conclusions IPL wRECD yielded improved estimates compared to SPL wRECD in high frequencies, where standing-wave interference is present. Independence from standing wave interference resulted in increased wRECD values above 4000 Hz using the IPL measurement paradigm. IPL wRECD is more reliable than SPL wRECD, does not require precise probe-microphone placement, and provides a wider valid wRECD bandwidth than SPL-based measurement.

Absorbance Measurements From Normal-hearing Ears in the National Health and Nutrition Examination Survey, 2015-2016 and 2017-2020.

To summarize absorbance and impedance angles from normal-hearing ears within the 2015-2016 and 2017-2020 US National Health and Nutrition Examination Surveys (NHANES). Two publicly available NHANES datasets were analyzed. Ears meeting criteria for normal hearing and valid absorbance and impedance angle measurements were identified. Measurements were summarized via descriptive statistics within categories of age cohort, race/ethnicity cohort, sex (male, female), and ear (left, right). A total of 7029 ears from 4150 subjects, ages 6 to 80 years, met inclusion criteria. Differences between subgroups within all categories (age, race/ethnicity, sex, and ear) were fractions of the sample SDs. The largest differences occurred between age cohorts younger than 20 years. The NHANES absorbance and impedance angle measurements are consistent with published literature. These results demonstrate that trained professionals, using the Titan instrument in a community setting inclusive of all demographics, produce comparable measurements to those in laboratory settings.

Event-Related Potentials of Single-Sided Deaf Cochlear Implant Users: Using a Semantic Oddball Paradigm in Noise

Introduction: In individuals with single-sided deafness (SSD), who are characterised by profound hearing loss in one ear and normal hearing in the contralateral ear, binaural input is no longer present. A cochlear implant (CI) can restore functional hearing in the profoundly deaf ear, with previous literature demonstrating improvements in speech-in-noise intelligibility with the CI. However, we currently have limited understanding of the neural processes involved (e.g., how the brain integrates the electrical signal produced by the CI with the acoustic signal produced by the normal hearing ear) and how modulation of these processes with a CI contributes to improved speech-in-noise intelligibility. Using a semantic oddball paradigm presented in the presence of background noise, this study aims to investigate how the provision of CI impacts speech-in-noise perception of SSD-CI users. Method: Task performance (reaction time, reaction time variability, target accuracy, subjective listening effort) and high density electroencephalography from twelve SSD-CI participants were recorded, while they completed a semantic acoustic oddball task. Reaction time was defined as the time taken for a participant to press the response button after stimulus onset. All participants completed the oddball task in three different free-field conditions with the speech and noise coming from different speakers. The three tasks were: (1) CI-On in background noise, (2) CI-Off in background noise, and (3) CI-On without background noise (Control). Task performance and electroencephalography data (N2N4 and P3b) were recorded for each condition. Speech in noise and sound localisation ability were also measured. Results: Reaction time was significantly different between all tasks with CI-On (M [SE] = 809 [39.9] ms) having faster RTs than CI-Off (M [SE] = 845 [39.9] ms) and Control (M [SE] = 785 [39.9] ms) being the fastest condition. The Control condition exhibited significantly shorter N2N4 and P3b area latency compared to the other two conditions. However, despite these differences noticed in RTs and area latency, we observed similar results between all three conditions for N2N4 and P3b difference area. Conclusion: The inconsistency between the behavioural and neural results suggests that EEG may not be a reliable measure of cognitive effort. This rationale is further supported by different explanations used in past studies to explain N2N4 and P3b effects. Future studies should look to alternative measures of auditory processing (e.g., pupillometry) to gain a deeper understanding of the underlying auditory processes that facilitate speech-in-noise intelligibility.