Auditory, Visual, and Cognitive Abilities in Normal-Hearing Adults, Hearing Aid Users, and Cochlear Implant Users.

OBJECTIVES: Speech understanding is considered a bimodal and bidirectional process, whereby visual information (i.e., speechreading) and also cognitive functions (i.e., top-down processes) are involved. Therefore, the purpose of the present study is twofold: (1) to investigate the auditory (A), visual (V), and cognitive (C) abilities in normal-hearing individuals, hearing aid (HA) users, and cochlear implant (CI) users, and (2) to determine an auditory, visual, cognitive (AVC)-profile providing a comprehensive overview of a person's speech processing abilities, containing a broader variety of factors involved in speech understanding. DESIGN: Three matched groups of subjects participated in this study: (1) 31 normal-hearing adults (mean age = 58.76), (2) 31 adults with moderate to severe hearing loss using HAs (mean age = 59.31), (3) 31 adults with a severe to profound hearing loss using a CI (mean age = 58.86). The audiological assessments consisted of pure-tone audiometry, speech audiometry in quiet and in noise. For evaluation of the (audio-) visual speech processing abilities, the Test for (Audio) Visual Speech perception was used. The cognitive test battery consisted of the letter-number sequencing task, the letter detection test, and an auditory Stroop test, measuring working memory and processing speed, selective attention, and cognitive flexibility and inhibition, respectively. Differences between the three groups were examined using a one-way analysis of variance or Kruskal-Wallis test, depending on the normality of the variables. Furthermore, a principal component analysis was conducted to determine the AVC-profile. RESULTS: Normal-hearing individuals scored better for both auditory, and cognitive abilities compared to HA users and CI users, listening in a best aided condition. No significant differences were found for speech understanding in a visual condition, despite a larger audiovisual gain for the HA users and CI users. Furthermore, an AVC-profile was composed based on the different auditory, visual, and cognitive assessments. On the basis of that profile, it is possible to determine one comprehensive score for auditory, visual, and cognitive functioning. In the future, these scores could be used in auditory rehabilitation to determine specific strengths and weaknesses per individual patient for the different abilities related to the process of speech understanding in daily life. CONCLUSIONS: It is suggested to evaluate individuals with hearing loss from a broader perspective, considering more than only the typical auditory abilities. Also, cognitive and visual abilities are important to take into account to have a more complete overview of the speech understanding abilities in daily life.

Changes in Tinnitus Characteristics and Residual Inhibition following Cochlear Implantation: A Prospective Analysis.

This study aims to explore the effect of cochlear implantation on tinnitus perception. A prospective study was conducted on 72 adult hearing-impaired patients to evaluate tinnitus perception before and after cochlear implantation, using standardized tinnitus questionnaires (the tinnitus sample case-history questionnaire, tinnitus functional index (TFI), and tinnitus handicap inventory (THI)). A large variety of demographic and hearing- and implant-related data was collected from patient hospital records to explore possible associations with the implantation effect. The prevalence of tinnitus complaints before implantation was 58.3%. The temporary induction or aggravation of tinnitus immediately after surgery was noted in 20% and 46.7% of patients, respectively. When evaluated 3 months after implantation, 60% of tinnitus patients experienced a clinically significant reduction in their complaints; most of the improvements were experienced immediately after activation of the implant. Only the scores for TFI and THI at baseline were found to be significantly correlated with a reduction in TFI scores after implantation. In 80% of tinnitus patients, the tinnitus remained suppressed for some time after taking off the device. The large subset of patients with residual inhibition supports the involvement of central pathophysiological processes in implantation effects on tinnitus, which are explored in this paper.

Longitudinal auditory data of children with prelingual single-sided deafness managed with early cochlear implantation.

Individuals with single-sided deafness (SSD) have no access to binaural hearing, which limits their ability to localize sounds and understand speech in noisy environments. In addition, children with prelingual SSD are at risk for neurocognitive and academic difficulties. Early cochlear implantation may lead to improved hearing outcomes by restoring bilateral hearing. However, its longitudinal impact on the development of children with SSD remains unclear. In the current study, a group of young children with prelingual SSD received a cochlear implant at an early age. From the age of four, the children's spatial hearing skills could be assessed using a spatial speech perception in noise test and a sound localization test. The results are compared to those of two control groups: children with SSD without a cochlear implant and children with bilateral normal hearing. Overall, the implanted group exhibited improved speech perception in noise abilities and better sound localization skills, compared to their non-implanted peers. On average, the children wore their device approximately nine hours a day. Given the large contribution of maturation to the development of spatial hearing skills, further follow-up is important to understand the long-term benefit of a cochlear implant for children with prelingual SSD.

Changes in Vestibular Function Following Pediatric Cochlear Implantation: a Prospective Study.

OBJECTIVES: Given the close interconnection between the auditory and vestibular end organs, the increasingly broad application of (bilateral) cochlear implantation (CI) in children raises concern about its impact on the vestibular function. Unfortunately, literature on this matter is inconclusive and subject to several limitations. Therefore, this study aimed to elucidate the impact of pediatric CI on the vestibular function in a large sample of children, representative for the current CI population. DESIGN: Fifty hearing-impaired children followed in the Ghent University Hospital were included in this prospective study. Twenty-seven patients underwent unilateral CI, and 23 were bilaterally implanted (9 sequentially, 14 simultaneously), adding up to 73 implanted ears. Children's median age at first implantation was 29 (range 8 to 194) months. Vestibular assessment was scheduled on average 2.8 months (SD: 3.6) before and 4.6 (SD: 4.0) months after implantation and consisted of video Head Impulse Testing of the lateral semicircular canals, rotatory testing (0.16, 0.04, and 0.01 Hz) and cervical vestibular evoked myogenic potential (cVEMP) testing with bone conduction stimulation. Caloric testing was added in children older than 3 years of age. RESULTS: Overall, group analysis in our sample of 73 CI-ears did not reveal any significant impact on the vestibular function, except for a significantly shortened ipsilateral N1 latency of the cVEMP responses (p = 0.027) after CI. Complete ipsilateral loss of function after implantation was seen in 5% (3/54) of all CI-ears on the video head impulse testing, in 0% (0/10) on the caloric test and in 2% (1/52) on the cVEMP, notably all patients deafened by a congenital cytomegalovirus infection. CONCLUSIONS: The impact of CI on the vestibular function in our dataset was limited. Therefore, the many advantages of simultaneous bilateral implantation may outweigh the risk for vestibular damage postoperatively. However, the impact on the vestibular function may be dependent on various factors (e.g., etiology of the hearing loss), and the clinical outcome is still difficult to predict. Vestibular assessment remains thus an important aspect in the pediatric CI population; first because the vestibular function should be considered in the decision-making process on (simultaneous or sequential bilateral) CI and second because it is essential to reveal a possible additional sensory deficit, allowing an opportunity for rehabilitation to improve the overall outcome of these children.

Short and long term preservation of hearing thresholds corrected for natural hearing loss in cochlear implant recipients using a straight electrode.

Objectives: The aim of this study is to investigate short and long term residual hearing preservation (HP), corrected for the natural progress of hearing loss, in cochlear implant (CI) patients receiving a straight electrode array using a round window (RW) approach.Methods: A retrospective and cross-sectional analysis on patients who received a CI with a straight electrode using a RW approach (n = 60) was performed. Audiometric data were obtained at three time points, preoperatively, at first fitting, and one year or more postoperatively. The HP outcome was calculated according to the HP definition as reported by Skarzynski with a PTA of 250, 500, and 1000 Hz (PTA3) and a PTA of 250, 500, 1000, and 2000 Hz (PTA4).Results: The HP outcome at first fitting and at long term follow up fell into the partial HP category, 63.5% (PTA3) and 40.5% (PTA4), respectively according to the Skarzynski definition. A decline in pure-tone average (PTA) was found in the CI ear and in the contralateral ear over time (p < 0.05). Interaural differences remained relatively stable at all frequencies on the long term, except for the frequency 250 Hz (p < 0.05).Discussion: After the initial loss of residual hearing, the hearing thresholds of the CI ear remain relatively stable at long term follow up when corrected for the natural course of hearing loss, except at 250 Hz.Conclusion: CI candidates should be counseled on the risk of long term deterioration of the residual hearing in both the CI ear and the contralateral ear.

Bilateral cochlear implantation or bimodal listening in the paediatric population: Retrospective analysis of decisive criteria.

INTRODUCTION: In children with bilateral severe to profound hearing loss, bilateral hearing can be achieved by either bimodal stimulation (CIHA) or bilateral cochlear implantation (BICI). The aim of this study was to analyse the audiologic test protocol that is currently applied to make decisions regarding the bilateral hearing modality in the paediatric population. METHODS: Pre- and postoperative audiologic test results of 21 CIHA, 19 sequential BICI and 12 simultaneous BICI children were examined retrospectively. RESULTS: Deciding between either simultaneous BICI or unilateral implantation was mainly based on the infant's preoperative Auditory Brainstem Response thresholds. Evolution from CIHA to sequential BICI was mainly based on the audiometric test results in the contralateral (hearing aid) ear after unilateral cochlear implantation. Preoperative audiometric thresholds in the hearing aid ear were significantly better in CIHA versus sequential BICI children (p < 0.001 and p = 0.001 in unaided and aided condition, respectively). Decisive values obtained in the hearing aid ear in favour of BICI were: An average hearing threshold measured at 0.5, 1, 2 and 4 kHz of at least 93 dB HL without, and at least 52 dB HL with hearing aid together with a 40% aided speech recognition score and a 70% aided score on the phoneme discrimination subtest of the Auditory Speech Sounds Evaluation test battery. CONCLUSIONS: Although pure tone audiometry offers no information about bimodal benefit, it remains the most obvious audiometric evaluation in the decision process on the mode of bilateral stimulation in the paediatric population. A theoretical test protocol for adequate evaluation of bimodal benefit in the paediatric population is proposed.

Phenotype of a Belgian Family With 6p25 Deletion Syndrome.

BACKGROUND: The 6p25 deletion syndrome is one of the many syndromes with both hearing impairment as well as vision impairment. However, the audiometric characteristics and radiological findings of patients with 6p25 deletions are only scarcely described in literature. This study focused on characterizing the audiometric and radiological features of a Belgian family with a chromosome 6p25 deletion. OBJECTIVE: To evaluate the hearing impairment, audiometric testing and radiological examination of the temporal bones in 3 family members with a 3.4 Mb deletion in chromosome band 6p25. RESULTS: All 3 family members demonstrated slowly progressive sensorineural or mixed hearing impairment. Radiologic examination revealed thickened and sclerotic stapes in all patients and a minor internal partition type II of the cochlea in 2 patients. CONCLUSION: There is a significant phenotypic variability within and among families with the 6p25 deletion syndrome. A thorough genotype-phenotype correlation is difficult because of the small number of affected patients and the limited clinical data available. More clinical data of families with 6p25 deletions need to be published in order to create a reliable and precise phenotypic characterization. However, our findings can facilitate counseling of hearing impairment caused by 6p25 deletions.

Auditory phenotype in Stickler syndrome: results of audiometric analysis in 20 patients.

Hearing loss in Stickler syndrome has received little attention due to the often more disabling ocular, orofacial and skeletal manifestations. Estimates suggest a global prevalence of sensorineural hearing loss (SNHL) ranging from 50 % to about 100 % though, depending on the underlying Stickler genotype. By performing extensive audiometric analysis in Stickler patients, we aimed to further elucidate the auditory phenotype. Twenty molecularly confirmed Stickler patients (age 10-62 year), of whom sixteen with type 1 Stickler syndrome (COL2A1 mutation) and four with type 2 Stickler syndrome (COL11A1 mutation) underwent an otological questionnaire, clinical examination, pure tone and speech audiometry, tympanometry and otoacoustic emission testing. Cross-sectional and longitudinal regression analysis of the audiograms was performed to assess progression. In type 1 Stickler syndrome, 75 % demonstrated hearing loss, predominantly in the high frequencies. No significant progression beyond presbyacusis was observed. All type 2 Stickler patients exhibited mild-to-moderate low- and mid-frequency SNHL and moderate-to-severe high-frequency SNHL. In both types, hearing loss was observed in childhood. Otoacoustic emissions were only detectable in 7/40 ears and had very low amplitudes, even in frequency bands with normal hearing on pure tone audiometry. Type 1 Stickler syndrome is characterized by a mild high-frequency SNHL, emerging in childhood and non-progressive. Absent otoacoustic emissions are a frequent finding. Patients with type 2 Stickler syndrome exhibit early-onset moderate SNHL affecting all frequencies with a sloping audiogram. Taking into account the visual impairment in many patients, we recommend regular auditory follow-up in patients with Stickler syndrome, especially in childhood.

Conversion of adult Nucleus® 5 cochlear implant users to the Nucleus® 6 system.

OBJECTIVES: Cochlear's new sound processor system (Nucleus(®) 6) features a new noise reduction algorithm called SNR-NR (signal-to-noise ratio), and an environmental classifier called SCAN, which activates the appropriate sound coding algorithms for a given listening environment. In addition, the sound processors (CP910 and CP920) have a data logging feature with data visually summarized using clinical programing software and come with two remote controls, CR210 and CR230. The objective of this clinical study was to conduct a field acceptance study comparing the user experience with the Nucleus(®) 6 to the Nucleus(®) 5 system and to evaluate the benefits of Nucleus(®) 6 in an adult population currently equipped with the previous generation Nucleus(®) 5 sound processor. Our primary objective was to compare speech recognition in speech-weighted noise using Nucleus(®) 6 with SCAN (activating SNR-NR) with the default Nucleus(®) 5 'Noise' Program. Secondary objectives included comparisons of speech recognition in quiet, subjective performance feedback via questionnaires and diaries, and recipient preference for device and program type. METHODS: A prospective controlled trial was conducted with 30 adult Nucleus CI recipients using the Nucleus(®) 5 sound processor (condition A). The Nucleus(®) 6 sound processor (condition B) was evaluated in a within-subject ABBA design, with repeated speech in noise (S0N0, LIST sentence test), and speech in quiet testing (S0, NVA words). The remote controls were randomly given during the two B intervals. In addition, recipients had to complete questionnaires and diaries on the use of their current as well as new sound processors and remotes. RESULTS: The group mean speech reception threshold in noise (SRT50) with Nucleus(®) 6 SCAN was significantly better (1.2 dB SNR) than with the Nucleus(®) 5 'Noise' Program. Mean speech recognition scores in quiet were not significantly different between the processors. Subjective performance feedback (APHAB) did not show a significant difference between Nucleus(®) 6 and Nucleus(®) 5 with high satisfaction scores being reported for both sound processors. Recipients preferred the SCAN program in noise and reported a clear overall preference for the Nucleus(®) 6 system. Clinicians were satisfied with the conversion process from Nucleus(®) 5 to Nucleus(®) 6. DISCUSSION AND CONCLUSION: SNR-NR provides a significant benefit in noise. Recipients were easily converted from Nucleus(®) 5 to Nucleus(®) 6 requiring little or no sound quality adjustment period. The Nucleus(®) 6 SCAN program was well accepted by the majority of recipients for use during their daily life.

Temporal bone imaging in osteogenesis imperfecta patients with hearing loss.

OBJECTIVES/HYPOTHESIS: Osteogenesis imperfecta (OI) is an autosomal-dominant connective-tissue disorder, predominantly characterized by bone fragility. Conductive hearing loss develops in half of the OI patients and often progresses to mixed loss. Findings of computed tomography (CT) and magnetic resonance (MR) imaging of the temporal bone in the largest series of OI patients to date are presented and correlated with the audiograms. STUDY DESIGN: Retrospective case series. METHODS: CT images and audiograms of 17 hearing-impaired OI patients, aged 9 to 67 years, were analyzed retrospectively. In four patients, MR imaging was performed as well. Imaging abnormalities were correlated with type and severity of hearing loss deduced from the audiograms. RESULTS: CT revealed fenestral hypodense foci in the fissula ante fenestram (25 of 33 ears), oval window (23 of 33 ears), and round window (20 of 33 ears). Retrofenestral hypodensities were observed, affecting the cochlear turns (16 of 33 ears), facial nerve canal (10 of 33 ears), or semicircular canals (6 of 33 ears), or appearing like the fourth turn of the cochlea (11 of 33 ears). The site of hypodensities corresponded to the type of hearing loss in 72.2% of the OI ears. The air-bone gap and bone-conduction thresholds showed significant positive associations with the number of affected fenestral (P < .05) and retrofenestral structures (P < .01), respectively. Gadolinium-enhanced MR images demonstrated active lesions in three patients with mixed hearing loss or deafness. CONCLUSIONS: The site of hypodensities on temporal bone CT images in OI corresponds to presence and type of hearing loss determined by audiometry. The more severe the hearing loss, the more affected temporal bone structures in OI.

Stapes surgery in osteogenesis imperfecta: retrospective analysis of 34 operated ears.

Intraoperative findings of stapes surgery in 34 ears from 22 patients with genetically confirmed osteogenesis imperfecta (OI) are reported, as well as the audiometric results after the longest postoperative follow-up published to date. Twenty-nine out of 34 ears underwent primary stapes surgery and 5 ears revision surgery. Postoperative audiometric follow-up ranged from 6 months to 37 years. Stapes footplates were fixed in all ears. Additionally, footplates were thickened or fragile, stapes crura atrophic or fractured, and middle ear mucosae thickened or hypervascularized. Short-term postoperative audiometry revealed improved hearing and reduced air-bone gaps in 28/29 primary operated ears and in all revision cases. In the 22 ears with long-term postoperative follow-up (mean duration: 16 years), hearing gain was still significant at the latest audiometric evaluation. Independently of the patients being diagnosed with OI type I or IV and independently of the underlying OI genotype, beneficial results are obtained in the majority of OI patients undergoing primary or revision stapes surgery for reduction of conductive hearing loss components caused by stapes footplate fixation. Despite the progressive course of the concomitant sensorineural component, hearing gain remains beneficial over several decades.

Association between bone mineral density and hearing loss in osteogenesis imperfecta.

OBJECTIVES/HYPOTHESIS: Osteogenesis imperfecta (OI) is a heritable connective tissue disorder, predominantly characterized by bone fragility. In half of the patients, progressive hearing loss develops, which is associated with abnormal bony changes involving the middle ear ossicles and stapes footplate. In the present study, we investigated whether the development of hearing loss in OI may be related to the overall aberrant bone quality. STUDY DESIGN: Observational study. METHODS: Following audiologic evaluation, 56 adult OI patients were classified as presenting normal hearing or conductive/mixed or pure sensorineural hearing loss. Areal bone mineral density (BMD) (aBMD) was measured using lumbar spine (LS) and whole body (WB) dual X-ray absorptiometry. By means of peripheral computed tomography, volumetric BMD (vBMD) and morphometric bone parameters were determined at distal and proximal radius, providing separate results for trabecular and cortical bone. The obtained bone parameters were compared between normal-hearing OI patients and those with either conductive/mixed or pure sensorineural hearing loss. RESULTS: Z scores demonstrated decreased LS aBMD, WB aBMD, and trabecular vBMD in OI adults compared to the healthy population. Patients with conductive/mixed hearing loss had lower trabecular vBMD compared to those with normal hearing or pure sensorineural loss at both whole-group and between-relatives comparisons. CONCLUSIONS: It is hypothesized that OI patients with lower BMD might be more susceptible to accumulating microfractures, which may interfere with the bone remodeling inhibition pathways in the temporal bone and, therefore, contribute to stapes footplate fixation and a conductive hearing loss component.

Audiologic phenotype of osteogenesis imperfecta: use in clinical differentiation.

OBJECTIVES: To describe the audiologic phenotype in osteogenesis imperfecta (OI). STUDY DESIGN: Observational study. SETTING: Tertiary referral center. PATIENTS: One hundred eighty-two patients with genetically confirmed OI, aged 3 to 89 years. INTERVENTION: Diagnostic hearing evaluation through otoadmittance and acoustic stapedius reflex measurements, pure tone, and speech audiometry. MAIN OUTCOME MEASURE(S): Prevalence, type, severity, symmetry, and audiometric configuration of the hearing loss in OI. Progression of hearing thresholds was determined by constructing age-related typical audiograms. RESULTS: Approximately 52.2% of all OI patients demonstrated hearing loss unilaterally (7.7%) or bilaterally (44.5%). Pure conductive, mixed, and pure sensorineural hearing losses were observed in 8.5%, 37.8%, and 11.6% of OI ears, respectively. Multiple linear regression revealed that thresholds progressed by 0.5 dB/yr at 0.25 kHz to 0.8 dB/yr at 0.8 kHz in the ears with conductive or mixed hearing loss. Pure sensorineural hearing loss progressed by less than 0.1 dB/yr at 0.25 kHz to 1.2 dB/yr at 8.0 kHz. Audiometric configuration was predominantly flat (70.5%) in the ears with conductive/mixed loss and sloping (50.0%) in those with pure sensorineural loss. CONCLUSION: Patients with OI are at risk for hearing loss. The hearing loss in OI may initiate at a young age and is progressive. However, the rate of progression, as well as the hearing loss severity, onset, and configuration depend on the type of hearing loss, which may be conductive/mixed or pure sensorineural. For both types, age-related threshold audiograms are constructed and may help the clinician to estimate the course of the hearing loss in patients with OI. In addition, they may be valuable to distinguish between hearing loss associated with OI and other similar forms of hearing loss, such as in otosclerosis.

Osteogenesis Imperfecta: the audiological phenotype lacks correlation with the genotype.

BACKGROUND: Osteogenesis Imperfecta (OI) is a heritable connective tissue disorder mainly caused by mutations in the genes COL1A1 and COL1A2 and is associated with hearing loss in approximately half of the cases. The hearing impairment usually starts between the second and fourth decade of life as a conductive hearing loss, frequently evolving to mixed hearing loss thereafter. A minority of patients develop pure sensorineural hearing loss. The interindividual variability in the audiological characteristics of the hearing loss is unexplained. METHODS: With the purpose of evaluating inter- and intrafamilial variability, hearing was thorougly examined in 184 OI patients (type I: 154; type III: 4; type IV: 26), aged 3-89 years, with a mutation in either COL1A1 or COL1A2 and originating from 89 different families. Due to the adult onset of hearing loss in OI, correlations between the presence and/or characteristics of the hearing loss and the underlying mutation were investigated in a subsample of 114 OI patients from 64 different families who were older than 40 years of age or had developed hearing loss before the age of 40. RESULTS: Hearing loss was diagnosed in 48.4% of the total sample of OI ears with increasing prevalence in the older age groups. The predominant type was a mixed hearing loss (27.5%). A minority presented a pure conductive (8.4%) or pure sensorineural (12.5%) loss. In the subsample of 114 OI subjects, no association was found between the nature of the mutation in COL1A1 or COL1A2 genes and the occurrence, type or severity of hearing loss. Relatives originating from the same family differed in audiological features, which may partially be attributed to their dissimilar age. CONCLUSIONS: Our study confirms that hearing loss in OI shows a strong intrafamilial variability. Additional modifications in other genes are assumed to be responsible for the expression of hearing loss in OI.

Clinical usefulness of the rotatory, caloric, and vestibular evoked myogenic potential test in unilateral peripheral vestibular pathologies.

OBJECTIVE: The aim of this study was to investigate the diagnostic capacity of three different rotatory tests, and to investigate the clinical effectiveness of the caloric, rotatory, and vestibular evoked myogenic potential (VEMP) test. DESIGN AND STUDY SAMPLE: Several rotatory tests--sinusoidal harmonic acceleration test (SHAT), pseudorandom rotation test (PRRT), velocity step test (VST)--and a caloric and a VEMP test, were given to 77 patients (mean age 52 years) with a unilateral peripheral vestibular pathology, and 80 control subjects (mean age 48 years). RESULTS: For the rotatory test, the highest diagnostic capacity was obtained with the 0.01 Hz SHAT frequency, followed by 0.1 and 0.05 Hz. A higher diagnostic accuracy was reached for the caloric and VEMP test. The caloric test demonstrated high sensitivity and specificity values, but the 0.01 Hz SHAT rotation appeared more sensitive, and the VEMP more specific, than the caloric test. CONCLUSION: A selection of the 0.01, 0.05, and 0.1 Hz SHAT rotations is suggested as the most ideal rotatory test protocol, and a combination of rotatory, caloric, and VEMP testing will result in a more complete examination of our vestibular system.

Speech recognition in noise with active and passive hearing protectors: a comparative study.

The perceived negative influence of standard hearing protectors on communication is a common argument for not wearing them. Thus, "augmented" protectors have been developed to improve speech intelligibility. Nevertheless, their actual benefit remains a point of concern. In this paper, speech perception with active earplugs is compared to standard passive custom-made earplugs. The two types of active protectors included amplify the incoming sound with a fixed level or to a user selected fraction of the maximum safe level. For the latter type, minimal and maximal amplification are selected. To compare speech intelligibility, 20 different speech-in-noise fragments are presented to 60 normal-hearing subjects and speech recognition is scored. The background noise is selected from realistic industrial noise samples with different intensity, frequency, and temporal characteristics. Statistical analyses suggest that the protectors' performance strongly depends on the noise condition. The active protectors with minimal amplification outclass the others for the most difficult and the easiest situations, but they also limit binaural listening. In other conditions, the passive protectors clearly surpass their active counterparts. Subsequently, test fragments are analyzed acoustically to clarify the results. This provides useful information for developing prototypes, but also indicates that tests with human subjects remain essential.

Short-term auditory effects of listening to an MP3 player.

OBJECTIVES: To determine the output levels of a commercially available MPEG layer-3 (MP3) player and to evaluate changes in hearing after 1 hour of listening to the MP3 player. DESIGN: First, A-weighted sound pressure levels (measured in decibels [dBA]) for 1 hour of pop-rock music on an MP3 player were measured on a head and torso simulator. Second, after participants listened to 1 hour of pop-rock music using an MP3 player, changes in hearing were evaluated with pure-tone audiometry, transient-evoked otoacoustic emissions, and distortion product otoacoustic emissions. PARTICIPANTS: Twenty-one participants were exposed to pop-rock music in 6 different sessions using 2 types of headphones at multiple preset gain settings of the MP3 player. MAIN OUTCOME MEASURES: Output levels of an MP3 player and temporary threshold and emission shifts after 1 hour of listening. RESULTS: The output levels at the full gain setting were 97.36 dBA and 102.56 dBA for the supra-aural headphones and stock earbuds, respectively. In the noise exposure group, significant changes in hearing thresholds and transient-evoked otoacoustic emission amplitudes were found between preexposure and postexposure measurements. However, this pattern was not seen for distortion product otoacoustic emission amplitudes. Significant differences in the incidence of significant threshold or emission shifts were observed between almost every session of the noise exposure group compared with the control group. CONCLUSIONS: Temporary changes in hearing sensitivity measured by audiometry and otoacoustic emissions indicate the potential harmful effects of listening to an MP3 player. Further research is needed to evaluate the long-term risk of cumulative noise exposure on the auditory system of adolescents and adults.

Determination and evaluation of clinically efficient stopping criteria for the multiple auditory steady-state response technique.

OBJECTIVE: The present study aimed at establishing clinically efficient stopping criteria for a multiple 80-Hz auditory steady-state response (ASSR) system. METHODS: In Experiment 1, data of 31 normal-hearing subjects were analyzed off-line to propose stopping rules. Consequently, ASSR recordings will be stopped when (1) all 8 responses reach significance and significance can be maintained for 8 consecutive sweeps; or (2) the mean noise levels were 4nV (if p-values were between 0.05 and 0.1, measurements were extended once by 8 sweeps); or (3) a maximum amount of 48 sweeps was attained; whichever occurred first. In Experiment 2, these stopping criteria were applied on 10 normal hearing and 10 hearing-impaired adults to assess the efficiency. RESULTS: The application of these stopping rules resulted in ASSR threshold values that were comparable to other ASSR research. Furthermore, preliminary analysis of the response and noise amplitudes demonstrated slightly higher values for hearing impaired than normal-hearing subjects. CONCLUSIONS: The proposed stopping rules can be used in adults to determine accurate ASSR thresholds within a time-frame of about 1h. SIGNIFICANCE: The use of these a priori stopping criteria might assist the clinician in their decision to terminate ASSR recordings.

Transient-evoked and distortion product otoacoustic emissions: A short-term test-retest reliability study.

Knowledge regarding the variability of transient-evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) is essential in clinical settings and improves their utility in monitoring hearing status over time. In the current study, TEOAEs and DPOAEs were measured with commercially available OAE-equipment in 56 normally-hearing ears during three sessions. Reliability was analysed for the retest measurement without probe-refitting, the immediate retest measurement with probe-refitting, and retest measurements after one hour and one week. The highest reliability was obtained in the retest measurement without probe-refitting, and decreased with increasing time-interval between measurements. For TEOAEs, the lowest reliability was seen at half-octave frequency bands 1.0 and 1.4 kHz; whereas for DPOAEs half-octave frequency band 8.0 kHz had also poor reliability. Higher primary tone level combination for DPOAEs yielded to a better reliability of DPOAE amplitudes. External environmental noise seemed to be the dominating noise source in normal-hearing subjects, decreasing the reliability of emission amplitudes especially in the low-frequency region.

The effect of age on the sinusoidal harmonic acceleration test, pseudorandom rotation test, velocity step test, caloric test, and vestibular-evoked myogenic potential test.

OBJECTIVES: Age-related anatomical and morphologic vestibular deterioration has already been elaborated. Demonstrating a corresponding degradation in physiologic function, however, entails a much higher challenge. The objective of this study was to investigate age-related changes using rotational tests, caloric tests, and the vestibular-evoked myogenic potentials (VEMP) test. DESIGN: Eighty healthy human subjects (38 men and 42 women) ranging in age from 18 to 80 yrs participated in this study and were subjected to an extensive vestibular test battery. Function tests included sinusoidal harmonic acceleration tests, a pseudorandom rotation test, velocity step tests, a caloric test, and a VEMP test. RESULTS: No significant age trends were noted for the sinusoidal harmonic acceleration test and velocity step tests response parameters, in contrast to subtle decreasing gain values with advancing age for the pseudorandom rotation test. Increasing slow-component velocity values were measured with the caloric test, whereas the frequency parameter showed no relevant age changes. The largest age trends were detected with the VEMP, with decreasing amplitudes, increasing thresholds, and decreasing N1 latencies. All asymmetry parameters remained stable across the different age categories. CONCLUSIONS: Only subtle age changes could be demonstrated with the rotational and caloric tests, in contrast to more pronounced age trends with the VEMP.