Improved directional hearing of children with congenital unilateral conductive hearing loss implanted with an active bone-conduction implant or an active middle ear implant.

Different amplification options are available for listeners with congenital unilateral conductive hearing loss (UCHL). For example, bone-conduction devices (BCDs) and middle ear implants. The present study investigated whether intervention with an active BCD, the Bonebridge, or a middle ear implant, the Vibrant Soundbridge (VSB), affected sound-localization performance of listeners with congenital UCHL. Listening with a Bonebridge or VSB might provide access to binaural cues. However, when fitted with the Bonebridge, but not with a VSB, binaural processing might be affected through cross stimulation of the contralateral normal hearing ear, and could interfere with processing of binaural cues. In the present study twenty-three listeners with congenital UCHL were included. To assess processing of binaural cues, we investigated localization abilities of broadband (BB, 0.5-20 kHz) filtered noise presented at varying sound levels. Sound localization abilities were analyzed separately for stimuli presented at the side of the normal-hearing ear, and for stimuli presented at the side of the hearing-impaired ear. Twenty-six normal hearing children and young adults were tested as control listeners. Sound localization abilities were measured under open-loop conditions by recording head-movement responses. We demonstrate improved sound localization abilities of children with congenital UCHL, when listening with a Bonebridge or VSB, predominantly for stimuli presented at the impaired (aided) side. Our results suggest that the improvement is not related to accurate processing of binaural cues. When listening with the Bonebridge, despite cross stimulation of the contralateral cochlea, localization performance was not deteriorated compared to listening with a VSB.

Evaluation of an abutment-level superpower sound processor for bone-anchored hearing.

OBJECTIVES: Performance of an abutment-level superpower sound processor for bone-anchored hearing, the Ponto 3 SuperPower from Oticon Medical (BCD2), was compared to an earlier model from Oticon Medical (BCD1). DESIGN: A comparative study in which each patient serves as its own control. SETTING: Tertiary clinic. PARTICIPANTS: Eighteen experienced BCD1 users with profound mixed hearing loss. MAIN OUTCOME MEASURES: Speech reception thresholds in noise; APHAB and SSQ questionnaires. RESULTS: In a group of 18 patients with severe mixed hearing loss, the performance of a recently introduced bone conduction device (BCD2) is evaluated relative to that of an earlier model (BCD1). Speech reception thresholds for the sentence-in-noise test in the speech and noise frontal condition are not significantly different (P > .05) for BCD1 and BCD2. Speech reception thresholds for frontal speech and three identical noise sources are 1.7 dB lower for BCD2 than for BCD1 (P < .05). With the APHAB questionnaire, the score for background noise is significantly lower (P < .01), that is more favourable, for BCD2 than for BCD1 with an effect size of 0.91. The APHAB domain scores for ease-of-communication, reverberation and aversiveness of loud sounds are not significantly different for both devices (P > .05). Scores for the speech, spatial and quality of hearing domains of the SSQ questionnaire are significantly higher (P < .01), that is more favourable, for BCD2 than for BCD1 with effect sizes of 1.22, 0.71 and 1.05, respectively. Scores for the SSQ-factors "speech understanding," "spatial," "clarity, separation and identification" and "listening effort and concentration" were all significantly higher (P < .05) for BCD2 than for BCD1, with effect sizes of 1.28, 0.64, 0.98 and 0.78, respectively. On a proprietary questionnaire, 16 patients indicate a preference for BCD2 over BCD1 for conversations in a small group and two patients have no preference for either device. In a large group, one patient prefers BCD1, six patients have no preference, and eleven patients prefer BCD2. When listening to music, all patients prefer BCD2 over BCD1, with a strong preference for BCD2 for seven patients. When asked for an overall preference, all patients prefer BCD2 over BCD1, with nine patients strongly preferring BCD2. CONCLUSIONS: The lower speech reception thresholds in noise with BCD2 relative to BCD1 can be attributed to the "speech omni" directionality mode of BCD2. The combination of an improved directionality for primarily low-level inputs and a higher maximum force output, relevant for mid- and high-level inputs, results in a clear preference for BCD2 over BCD1.

On the evaluation of a superpower sound processor for bone-anchored hearing.

OBJECTIVES: Performance of a superpower bone-anchored hearing aid (Baha), the Baha Cordelle from Cochlear Bone-Anchored Solutions (BCD1), was compared to its successor, the Baha 5 SuperPower (BCD2). DESIGN: A comparative study in which each patient served as its own control. SETTING: Tertiary clinic. PARTICIPANTS: Ten experienced BCD1 users with profound mixed hearing loss. For comparison, data from another study with 10 experienced users with a severe mixed hearing loss using a Cochlear Baha 5 power sound processor (BCD-P) were included. MAIN OUTCOME MEASURES: Speech reception thresholds in noise and APHAB and SSQ questionnaires. RESULTS: Speech reception thresholds for the digits-in-noise (DIN) test were significantly lower (P < 5%), that is more favourable, for BCD2 in the speech and noise frontal condition and in the speech frontal and noise contralateral condition than for BCD1. For the group with severe mixed loss fitted with BCD-P, the SRTs were not significantly different (P > 5%) from the BCD2 values. With the APHAB questionnaire scores were significantly lower, that is more favourable, for the ease of communication (P < 5%) and the background noise (P < 1%) domains for BCD2 than for BCD1. APHAB scores for the aversiveness of loud sounds domain were not significantly different for both devices (P > 5%). Scores for the speech and quality domains of the SSQ questionnaire were significantly higher, that is more favourable, for BCD2 than for BCD1. APHAB and SSQ scores for BCD-P were not significantly different from those for BCD2 (P > 5%). CONCLUSIONS: Data for BCD2 in profound mixed loss are similar to those for BCD-P and a severe mixed loss. Of 10 patients, 2 expressed a strong preference for BCD2 over BCD1, and 7 patients had a preference for BCD2 over BCD1. One patient preferred BCD1 because of its built-in telecoil facility.

Determining fitting ranges of various bone conduction hearing aids.

OBJECTIVES: To define fitting ranges for nine bone conduction devices (BCDs) over different frequencies based on the device's maximum power output (MPO) and to validate the assessment of MPO of BCDs in the ear canal. BACKGROUND: Maximum power output (MPO) is an important characteristic when fitting BCDs. It is the highest output level a device can deliver and is one of the major determinants of a device's fitting range. A skull simulator can be used to verify MPO of percutaneous BCDs. No such simulator is available for active and passive transcutaneous devices. DESIGN: The MPO of nine different BCDs was assessed either by real-ear measurements and/or with skull simulator measurements. MAIN OUTCOME MEASURES: MPO and cross-validation of the methods using the Bland-Altman method. RESULTS: Percutaneous BCDs have higher MPO levels compared to active and passive transcutaneous devices. This results in a wide dynamic range of hearing for percutaneous devices. Moreover, the assessment of MPO by real-ear measurements was validated. CONCLUSION: Based on MPO data, fitting ranges were defined for nine BCDs over seven frequencies.

Audiometric characteristics of a dutch family with a new mutation in GATA3 causing HDR syndrome.

We present the case of a Dutch family with a new mutation (c523_528dup) in GATA3 causing HDR syndrome. HDR syndrome is characterised by hypoparathyroidism, deafness and renal defects. In this study, we describe the audiometric characteristics of 5 patients from this family. Their hearing impairment was congenital, bilateral and symmetric. Audiograms showed mild-to-moderate hearing impairment with a flat audiogram configuration. Higher frequencies tended to be affected more strongly. Cross-sectional analyses showed no progression, and a mean audiogram was established. Psychophysical measurements in 3 HDR patients - including speech reception in noise, loudness scaling, gap detection and difference limen for frequency - were obtained to assess hearing function in greater detail. Overall, the results of the psychophysical measurements indicated characteristics of outer hair cell loss. CT scanning showed no anomalies in 3 of the HDR patients. Although 2 patients displayed vestibular symptoms, no anomalies in the vestibular system were found by vestibulo-ocular examination. Our results are in agreement with the theory that outer hair cell malfunctioning can play a major role in HDR syndrome.

Progressive hereditary hearing impairment caused by a MYO6 mutation resembles presbyacusis.

Since deafness is the most common sensorineural disorder in humans, better understanding of the underlying causes is necessary to improve counseling and rehabilitation. A Dutch family with autosomal dominantly inherited sensorineural hearing loss was clinically and genetically assessed. The MYO6 gene was selected to be sequenced because of similarities with other, previously described DFNA22 phenotypes and a pathogenic c.3610C > T (p.R1204W) mutation was found to co-segregate with the disease. This missense mutation results in a flat configured audiogram with a mild hearing loss, which becomes severe to profound and gently to steeply downsloping later in life. The age-related typical audiograms (ARTA) constructed for this family resemble presbyacusis. Speech audiometry and results of loudness scaling support the hypothesis that the phenotype of this specific MYO6 mutation mimics presbyacusis.

Audiometric characteristics of two Dutch families with non-ocular Stickler syndrome (COL11A2).

OBJECTIVE: To evaluate hearing impairment and cochlear function in non-ocular Stickler syndrome. STUDY DESIGN: Multifamily study. PATIENTS & METHODS: Ten patients from two different families with non-ocular Stickler syndrome (Stickler syndrome type 3) were included. Six members of the first family and four members of the second family participated in this study. Otorhinolaryngologic examinations were performed. Pure-tone and speech audiograms were obtained. Longitudinal analysis was performed. Psychophysical measurements, including loudness scaling, gap detection, difference limen for frequency and speech perception in noise were administered to assess cochlear function at a deeper level. RESULTS: Affected individuals in the first family were carriers of a heterozygous splice donor mutation in the COL11A2 gene. Affected individuals in the second family were carriers of a novel heterozygous missense mutation in COL11A2. Both families showed bilateral, non-progressive hearing impairment with childhood onset. The severity of the hearing impairment exhibited inter- and intrafamilial variability and was mostly mild to moderate. The results of the psychophysical measurements were similar to those previously published for DFNA8/12 (TECTA) and DFNA13 (COL11A2) patients and thus consistent with an intra-cochlear conductive hearing impairment. This is in line with the theory that mutations in COL11A2 affect tectorial membrane function. CONCLUSION: Hearing impairment in non-ocular Stickler syndrome is characterized by non-progressive hearing loss, present since childhood, and mostly mild to moderate in severity. Psychophysical measurements in non-ocular Stickler patients were suggestive of intra-cochlear conductive hearing impairment.

Sound localization and binaural hearing in children with a hearing aid and a cochlear implant.

The aims of the study were to investigate whether sound localization acuity improved when children with 1 cochlear implant use a hearing aid in the contralateral ear (bimodal fitting), and whether this enabled them to benefit from a binaural masking level difference. Four different noise bursts were used as stimuli for a minimal audible angle localization test. On average, localization acuity remained poor with the cochlear implant alone, but also with bimodal fitting. A significant benefit of bimodal fitting was only shown when the most complicated stimulus with roved amplitude and spectrum was presented (minimal audible angle of 151 degrees with bimodal fitting vs. 175 degrees with cochlear implant alone). No significant binaural masking level difference was found between the cochlear implant alone and the bimodal condition.

The Baha Softband. A new treatment for young children with bilateral congenital aural atresia.

The Baha (bone-anchored hearing aid) Softband appears to be an effective mean of hearing rehabilitation for children with a congenital bilateral aural atresia who are too young for the amplification of a Baha on an implant. The aided hearing threshold with a Baha Softband is almost equal to that achieved with a conventional bone conductor. The speech development of the children studied with a Baha Softband is on a par with peers with good hearing.

Speech perception in congenitally, pre-lingually and post-lingually deaf children expressed in an equivalent hearing loss value.

OBJECTIVES: To investigate the speech perception performance of children with a cochlear implant (CI) after 3 and 4 years of follow-up and to study the influence of age at implantation, duration of deafness and communication mode on the variability in speech perception performance. STUDY DESIGN: A broad battery of speech perception tests was administered to 67 children with a CI. The results were reduced into one measure: the 'equivalent hearing loss (EHL)'. This outcome measure refers to the performance of a reference group of severely and profoundly hearing impaired children with conventional hearing aids. PARTICIPANTS: The population comprised 35 congenitally, 17 pre-lingually and 15 post-lingually deaf children implanted between 1989 and 1999. The population was homogeneous with respect to cognition, residual hearing and support at home as a result of conservative inclusion criteria. RESULTS: During the first 2 years after implantation, post-lingually deaf children showed the fastest rate of improvement in speech perception. After 3 years of implant use, the early implanted pre-lingually deaf children and congenitally deaf children implanted under the age of 6 years caught up with the post-lingually deaf children. Pre-lingually deaf children implanted after a relatively long-duration of deafness tended to show poorer performance than those with a shorter duration. Performance of congenitally deaf children implanted after the age of 6 years was poorer and progress was slower. In the congenitally deaf children, 36% of the variability in performance was explained by duration of deafness, whereas in the children with pre- and post-lingually acquired deafness, communication mode explained 69% of the variance. CONCLUSIONS: All children derived benefit from their CI for speech perception tasks, but performance varied greatly. Several children reached EHL levels around 70 dB; their speech perception was equal to that of a child with conventional hearing aids who has 70 dB HL. After early implantation, the levels of performance that were eventually achieved differed no more than 10 dB, irrespective of whether the onset of deafness was pre-lingual or postlingual. In congenitally deaf children, duration of deafness played a major role in speech perception performance, whereas in the children with pre-lingually and post-lingually acquired deafness together, mode of communication was a major factor.

Education qualification levels and school careers of unilateral versus bilateral hearing aid users.

OBJECTIVE: Analyse the difference in school careers and secondary school qualification levels between unilateral hearing aid users and bilateral hearing aid users. STUDY DESIGN: Retrospective questionnaire study. SETTING: Postal-based questionnaire. PARTICIPANTS: Names of adults known to have been fitted with unilateral or bilateral hearing aids during childhood were retrieved. This resulted in 292 names. Participants were selected using the following criteria: availability of the medical record, presence of bilateral hearing loss, completed secondary school education, normal IQ and a minimum aided word-recognition score of 70% at 10 years of age. The questionnaire was sent to 50 potential participants of whom 40 responded, resulting in two groups comprising 19 unilateral and 21 bilateral hearing aid users. METHODS: A questionnaire was developed to obtain data on secondary school levels and aspects of the school careers, such as type of schools attended (mainstream versus special), repeating a school year and additional assistance (speech and language therapy, personal frequency modulation systems). MAIN OUTCOME MEASURES: Comparison of the benefit of bilateral hearing aid fitting versus unilateral hearing aid fitting on secondary school qualification level, type of school the children attended, class failure and additional assistance used. RESULTS: The group of bilaterally fitted hearing aid users eventually completed secondary school at a superior level than the unilaterally fitted users. 33% of binaural hearing aid users achieved qualifications giving access to a bachelors degree compared with 21% of unilateral users. There were no differences between those fitted with unilateral and bilateral hearing aids in the type of schools attended, repeating a school year and additional assistance. CONCLUSIONS: The bilateral hearing aid users obtained superior secondary school qualifications than the unilateral users but their school careers were comparable.

Discrimination of speech sound contrasts determined with behavioral tests and event-related potentials in cochlear implant recipients.

Cortical potentials evoked with speech stimuli were investigated in ten experienced cochlear implant (CI, type Nucleus 24M) users using three different speech-coding strategies and two different speech contrasts, one vowel (/i/-/a/) and one consonant (/ba/-/da/) contrast. On average, results showed that, compared to subjects with normal hearing, P300 amplitudes were smaller; however, most latencies were within the normal range. Next, individual P300 measures in response to the two speech contrasts were compared to behavioral discrimination scores. Significant within-subject differences in P300 amplitudes and latencies were found for the three speech coding strategies. These differences were in agreement with the behavioral, strategy-dependent discrimination of the speech contrasts.

Use of the event-related P300 potential in cochlear implant subjects for the study of strategy-dependent speech processing.

The present overview is a compilation of the results of several event-related potential (ERP) studies on auditory cortical processing, performed in the Evoked Potential Laboratory of the University Medical Centre of Nijmegen. To study speech perception performance in cochlear implant (CI) subjects, ERPs were obtained from subjects with poor and moderate performance. The present report describes the relationships between speech-coding strategies, the presentation of speech by the CI processor, the P300 potential as a measure of speech discrimination, time effects in the long term and speech recognition in relation to ERPs.