Evaluation of a super powerful bone-anchored hearing system and its users: A retrospective study.

INTRODUCTION: Although the Baha 5SP has been commercially available for six years, very few studies have been performed on the device's efficacy. The current study aims to evaluate the characteristics and audiological results in patients with severe-to-profound mixed hearing loss fitted with this superpower sound processor. METHODS: This retrospective evaluation was conducted at a tertiary referral centre where a series of 82 adult patients with severe-to-profound mixed hearing loss were implanted with a percutaneous bone-anchored hearing system and fitted with a superpower sound processor between 2016 and 2019. Patients with incomplete or unreliable audiological data (n = 24) were excluded, resulting in 58 data sets for analysis. The main outcome measures were unaided and aided pure-tone thresholds and aided free-field speech perception in quiet. RESULTS: The median unaided air conduction (AC) threshold averaged across 0.5, 1 and 2 kHz (PTA0.5-2kHz) of all patients was 75 dB hearing loss (HL); the median unaided AC averaged across 1, 2 and 4 kHz (PTA1-4kHz) was 84 dB HL. For bone conduction and direct bone conduction, the median PTA0.5-2kHz was 52 and 47 dB HL, respectively. With the superpower device, the median free-field speech reception threshold was 54 dB sound pressure level (SPL), and the median speech perception score at 65 dB SPL was 80%. CONCLUSIONS: At least 75% of the patients reached a maximum phoneme score of 70%. For patients with lower scores, the superpower device still provides a substantial hearing benefit. This makes the superpower device particularly suitable for patients with severe-to-profound mixed hearing loss with a contraindication for conventional hearing aids and/or cochlear implants.

Measurement and optimisation of the perceptual equivalence of the Dutch consonant-vowel-consonant (CVC) word lists using synthetic speech and list pairs.

OBJECTIVES: (1) to determine whether the standard Dutch word lists for speech audiometry are equally intelligible in normal-hearing listeners (Experiment 1), (2) to investigate whether synthetic speech can be used to create word lists (Experiment 1) and (3) to determine whether the list effect found in Experiment 1 can be reduced by combining two lists into pairs (Experiment 2). DESIGN: Participants performed speech tests in quiet with the original (natural) and synthetic word lists (Experiment 1.). In Experiment 2, new participants performed speech tests with list pairs from the original lists constructed from the results of Experiment 1. STUDY SAMPLES: Twenty-four and twenty-eight normal-hearing adults. RESULTS: There was a significant list effect in the natural speech lists; not in the synthetic speech lists. Variability in intelligibility was significantly higher in the former, with list differences up to 20% at fixed presentation levels. The 95% confidence interval of a list with a score of approximately 70% is around 10%-points wider than of a list pair. CONCLUSIONS: The original Dutch word lists show large variations in intelligibility. List effects can be reduced by combining two lists per condition. Synthetic speech is a promising alternative to natural speech in speech audiometry in quiet.

Genetic Hearing Loss Affects Cochlear Processing.

The relationship between speech recognition and hereditary hearing loss is not straightforward. Underlying genetic defects might determine an impaired cochlear processing of sound. We obtained data from nine groups of patients with a specific type of genetic hearing loss. For each group, the affected cochlear site-of-lesion was determined based on previously published animal studies. Retrospectively obtained speech recognition scores in noise were related to several aspects of supra-threshold cochlear processing as assessed by psychophysical measurements. The differences in speech perception in noise between these patient groups could be explained by these factors and partially by the hypothesized affected structure of the cochlea, suggesting that speech recognition in noise was associated with a genetics-related malfunctioning of the cochlea. In particular, regression models indicate that loudness growth and spectral resolution best describe the cochlear distortions and are thus a good biomarker for speech understanding in noise.

Investigating Real-World Benefits of High-Frequency Gain in Bone-Anchored Users with Ecological Momentary Assessment and Real-Time Data Logging.

PURPOSE: To compare listening ability (speech reception thresholds) and real-life listening experience in users with a percutaneous bone conduction device (BCD) with two listening programs differing only in high-frequency gain. In situ real-life experiences were recorded with ecological momentary assessment (EMA) techniques combined with real-time acoustical data logging and standard retrospective questionnaires. METHODS: Nineteen experienced BCD users participated in this study. They all used a Ponto 4 BCD from Oticon Medical during a 4-week trial period. Environmental data and device parameters (i.e., device usage and volume control) were logged in real-time on an iPhone via a custom iOS research app. At the end of the trial period, subjects filled in APHAB, SSQ, and preference questionnaires. Listening abilities with the two programs were evaluated with speech reception threshold tests. RESULTS: The APHAB and SSQ questionnaires did not reveal any differences between the two listening programs. The EMAs revealed group-level effects, indicating that in speech and noisy listening environments, subjects preferred the default listening program, and found the program with additional high-frequency gain too loud. This finding was corroborated by the volume log-subjects avoided the higher volume control setting and reacted more to changes in environmental sound pressure levels when using the high-frequency gain program. Finally, day-to-day changes in EMAs revealed acclimatization effects in the listening experience for ratings of "sound quality" and "program suitability" of the BCD, but not for ratings of "loudness perception" and "speech understanding". The acclimatization effect did not differ among the listening programs. CONCLUSION: Adding custom high-frequency amplification to the BCD target-gain prescription improves speech reception in laboratory tests under quiet conditions, but results in poorer real-life listening experiences due to loudness.

Results of a 2-Year Prospective Multicenter Study Evaluating Long-term Audiological and Clinical Outcomes of a Transcutaneous Implant for Bone Conduction Hearing.

OBJECTIVE(S): To evaluate 2-year audiological and clinical outcomes of a transcutaneous implant for bone conduction hearing of a previously published 6-month evaluation. DESIGN: Fifty-four unilaterally implanted adult patients with conductive or mild mixed hearing loss or single-sided sensorineural deafness were included in this prospective multicenter study. Follow-up visits were scheduled post-surgery at 10 days; 4, 6, and 12 weeks; 6, 12, and 24 months. Main outcomes were audiological benefit, patient-reported outcomes (PROs), soft tissue status, pain, numbness, implant survival, and daily usage. RESULTS: In the study population, the transcutaneous implant resulted in statistically significant improvement in objective hearing test and PROs compared with the unaided situation. Soft tissue complications were observed in 4.6% of the patients per visit. Pain/discomfort and numbness were initially reported in the majority of the patients, but declined over time; approximately 9% of patients reported some degree of numbness and 15% (slight) pain/discomfort after 2 years. During the 24-month period, two implant magnets were removed (3.7%), while two other implants were converted to the percutaneous counterpart (3.7%). At the final visit, 89.6% (n = 42 out of 47) of the patients used their sound processor, with a median daily usage of 6 h/d (range, 0-18 h/d). CONCLUSIONS: After 24 months, the transcutaneous implant provided statistically significant mean improvement in objective and subjective hearing performance as well as PROs compared with the preoperative unaided condition and had a low soft tissue complication rate. The test device could be considered as an alternative treatment option for appropriately selected and counseled patients.

The Merits of Bilateral Application of Bone-Conduction Devices in Children With Bilateral Conductive Hearing Loss.

OBJECTIVES: This study aims to characterize lateralization of sounds and localization of sounds in children with bilateral conductive hearing loss (BCHL) when listening with either one or two percutaneous bone conduction devices (BCDs). DESIGN: Sound lateralization was measured with the minimum audible angle test in which children were asked to indicate from which of the two visible speakers the sound originated. Sound localization was measured with a test in which stimuli were presented from speakers that were not visible to the children. In the sound localization test, 150 ms broadband noise bursts were presented, and sound level was roved over a 20-dB range. Because speakers were not visible the localization response was not affected by any visual cue. The sound localization test provides a clear distinction between lateralization and localization of sounds. Ten children with congenital BCHL and one child with acquired BCHL participated. RESULTS: Both lateralization and sound localization were better with bilateral BCDs compared with the unilaterally aided conditions. In the bilateral BCD condition, lateralization was close to normal in nearly all the children. The localization test demonstrated lateralization rather than sound localization behavior when listening with bilateral BCDs. Furthermore, in the unilateral aided condition, stimuli presented at different sound levels were mainly perceived at the same location. CONCLUSIONS: This study demonstrates that, in contrast to listening with two BCDs, children demonstrated difficulties in lateralization of sounds and in sound localization when listening with just one BCD (i.e., one BCD turned off). Because both lateralization and sound localization behavior were tested, it could be demonstrated that these children are more able to lateralize than localize sounds when listening with bilateral BCDs. The present study provides insight in (sub-optimal) sound localization capabilities of children with congenital BCHL in the unilateral-aided and bilateral-aided condition. Despite the sub-optimal results on sound localization, this study underlines the merits of bilateral application of BCDs in such children.

Efficacy of Auditory Implants for Patients With Conductive and Mixed Hearing Loss Depends on Implant Center.

INTRODUCTION: Although from a technological point of view, progress is impressive, most implantable hearing devices for conductive or mixed hearing loss have a limited capacity. These devices all bypass the impaired middle ear; therefore, the desired amplification (gain) should be based on the cochlear hearing loss (component) only. The aim of the study is to review the literature with regard to accomplished gain with current implantable devices. METHOD: Thirty-one articles could be included. Aided thresholds were compared with prescribed values, based on cochlear hearing loss (bone-conduction thresholds), according to the well-validated NAL rule. RESULTS: For the majority of the studies, NAL targets were not met. Variation in accomplished gain between implant teams was unacceptably large, largely independent of the type of device that was used. NAL targets were best met at 2 kHz, with worse results at the other frequencies. CONCLUSION: Large variations in reported results were found, which primarily depended on implant center. Based on the analyses, a pragmatic fitting procedure is proposed which should minimize the differences between implant centres.

Three-Year Clinical and Audiological Outcomes of Percutaneous Implants for Bone Conduction Devices: Comparison Between Tissue Preservation Technique and Tissue Reduction Technique.

OBJECTIVES: To evaluate the three-year clinical and audiological outcomes of soft-tissue preservation compared to soft-tissue reduction in linear incision surgery for percutaneous implant for bone conduction (BC) devices. METHODS: Twenty-five patients (25 implants) were enrolled in a prospective cohort for implant surgery with linear incision and tissue preservation. The control group consisted of 25 patients (25 implants) from a previous randomized controlled trial in which a linear incision with soft-tissue reduction was applied. Follow-up visits were scheduled at 7 and 21 days (fitting of sound processor); 12 weeks; 6 months; and at 1, 2, and 3 years after implantation. Main outcome measures were skin sensibility, soft-tissue status, Implant Stability Quotient (ISQ), skin height, implant survival, revision surgery, scar assessment, and hearing thresholds (BC in-situ between 250 Hz and 8 kHz with BC device on testband and abutment, and BC thresholds at 250Hz-4 kHz with a B71 bone conductor). RESULTS: Tissue preservation resulted in superior sensibility (mean percentage correct responses 99.7% [SD 1.7] vs 92.0% [SD 9.2], p = 0.0001). No spontaneous implant loss occurred in either group. The abutment was removed in two tests and in one control patient. Two control patients needed skin revision surgery. Although not statistically significant, more adverse soft-tissue reactions (Holgers ≥2) were observed in the test-group (n = 9 [36%] vs n = 3 [12%], p = 0.095). ISQ increased significantly more in the test group compared to the control group (7.64 [SD 4.05] vs 4.29 [SD 3.93]). Skin thickening, scar assessment, and hearing outcomes were comparable. CONCLUSION: Tissue preservation demonstrated superior skin sensibility compared to tissue reduction while other clinical outcomes were comparably excellent.

Audiological and clinical outcomes of a transcutaneous bone conduction hearing implant: Six-month results from a multicentre study.

OBJECTIVES: To compare the hearing performance of patients with conductive and mild mixed hearing loss and single-sided sensorineural deafness provided with a new transcutaneous bone conduction hearing implant (the Baha Attract System) with unaided hearing as well as aided with a sound processor on a softband. Furthermore, to evaluate safety and subjective benefit before and after implantation of the test device. PARTICIPANTS: Fifty-four adult patients in five participating centres were enrolled in this prospective study. Baseline data were collected during a pre-operative visit, and after a softband trial, all patients were implanted unilaterally. Follow-up visits were scheduled at 10 days, 4, 6, 12 weeks and 6 months. MAIN OUTCOME MEASURES: Free-field hearing thresholds pure-tone average (PTA4 in dB HL; mean threshold at 500, 1000, 2000, 4000 Hz; primary outcome measure). Individual free-field hearing thresholds, speech recognition in quiet and in noise, soft tissue status during follow-up and subjective benefit as measured with the Abbreviated Profile of Hearing Aid Benefit (APHAB), Speech, Spatial and Qualities of Hearing Scale (SSQ) and Health Utilities Index (HUI) questionnaires. RESULTS: Implantation of the Baha Attract System resulted in favourable audiological outcomes compared to unaided conditions. On the primary outcome parameter, a statistically significant improvement was observed compared to unaided hearing for the patients with conductive/mixed hearing loss (mean PTA4 difference -20.8 dB HL, SD 9.8; P < 0.0001) and for the patients with single-sided sensorineural deafness (SSD) (mean PTA4 difference -21.6 dB HL, SD 12.2; P < 0.0001). During all audiology tests, the non-test ear was blocked. Statistically significant improvements were also recorded in speech tests in quiet and noise compared to unaided hearing for the conductive/mixed hearing loss group and for speech in quiet in the SSD group. Compared to the pre-operative measurement with softband, no significant differences were recorded in the PTA4 free-field hearing threshold or the other audiological outcomes in either of the groups (P > 0.05). Soft tissue-related issues observed during follow-up included numbness, pain/discomfort at the implant site and to a lesser extent pressure-related skin complications. A declining trend was noted in the rate of these complications during follow-up. Approximately 20% of patients reported some degree of numbness and 38% (slight) pain/discomfort at final follow-up of 6 months. Good results on the subjective benefit questionnaires were observed, with statistically significant improvements on APHAB and SSQ questionnaires, and on the hearing attribute of HUI3. CONCLUSIONS: The Baha Attract System provided a significant improvement in hearing performance and subjective benefit compared to the pre-operative unaided condition (with the non-test ear blocked). Hearing performance of the Baha Attract was similar to a test situation with the same sound processor on a softband. A proportion of the patients reported numbness and pain/discomfort at the implant site during follow-up, especially during the first post-operative weeks. Based on the results of the current multicentre study, the Baha Attract can be considered as a treatment option for patients with the aforementioned hearing losses. Especially in the SSD patients, a careful selection procedure is warranted. Therefore, a pre-operative trial should be part of the decision-making process before fitting a patient with the Baha Attract System.

Controlled Clinical Trial on Bone-anchored Hearing Implants and a Surgical Technique With Soft-tissue Preservation.

OBJECTIVE: To compare the clinical and audiological outcomes after linear incision with soft-tissue preservation and standard linear incision with soft-tissue reduction for placement of percutaneous bone-anchored hearing implants. STUDY DESIGN: Clinical trial with historical control-group from a previous randomized controlled trial. SETTING: Tertiary referral center. PATIENTS AND INTERVENTIONS: Twenty-five patients were enrolled in a prospective cohort of bone-anchored hearing implant placement with linear incision and tissue preservation with a follow-up of 6 months. The control-group consisted of 25 patients from a previous randomized controlled trial in the same tertiary referral center. All sound processors were fitted 3 weeks after surgery. MAIN OUTCOME MEASURES: Numbness around the abutment, length of surgery, soft-tissue reactions according to Holgers' classification, Patient and Observer Scar Assessment Scale, implant loss, Implant Stability Quotient, and audiological outcome. RESULTS: Tissue preservation resulted in better results on sensibility (mean percentage correct responses 98% [SD 4.4] versus 89% [SD 15.0], p = 0.003), on the Patient and Observer Scar Assessment Scale (mean observer score 15.3 [SD 4.3] versus 19.4 [SD 6.3], p = 0.006), and shorter total surgery time (mean 24.6 min [SD 6.2] versus 31.9 min [SD 6.5], p < 0.001). More adverse soft-tissue reactions as measured by the Holgers classification were observed in the test-group (n = 7 [28%] versus n = 1 [4%], p = 0.049). For Implant Stability Quotient and audiology the study did not provide evidence that tissue preservation is better or worse compared with tissue reduction. CONCLUSION: Tissue preservation compared with tissue reduction leads to a generally favorable clinical outcome, comparable audiology results, and significantly shorter surgery time. Longer follow-up is warranted to conclude on the increased adverse soft-tissue reactions after 6 months.

How to quantify binaural hearing in patients with unilateral hearing using hearing implants.

Application of bilateral hearing devices in bilateral hearing loss and unilateral application in unilateral hearing loss (second ear with normal hearing) does not a priori lead to binaural hearing. An overview is presented on several measures of binaural benefits that have been used in patients with unilateral or bilateral deafness using one or two cochlear implants, respectively, and in patients with unilateral or bilateral conductive/mixed hearing loss using one or two percutaneous bone conduction implants (BCDs), respectively. Overall, according to this overview, the most significant and sensitive measure is the benefit in directional hearing. Measures using speech (viz. binaural summation, binaural squelch or use of the head shadow effect) showed minor benefits, except for patients with bilateral conductive/mixed hearing loss using two BCDs. Although less feasible in daily practise, the binaural masking level difference test seems to be a promising option in the assessment of binaural function.

Wireless and acoustic hearing with bone-anchored hearing devices.

OBJECTIVE: The efficacy of wireless connectivity in bone-anchored hearing was studied by comparing the wireless and acoustic performance of the Ponto Plus sound processor from Oticon Medical relative to the acoustic performance of its predecessor, the Ponto Pro. STUDY SAMPLE: Nineteen subjects with more than two years' experience with a bone-anchored hearing device were included. Thirteen subjects were fitted unilaterally and six bilaterally. DESIGN: Subjects served as their own control. First, subjects were tested with the Ponto Pro processor. After a four-week acclimatization period performance the Ponto Plus processor was measured. In the laboratory wireless and acoustic input levels were made equal. In daily life equal settings of wireless and acoustic input were used when watching TV, however when using the telephone the acoustic input was reduced by 9 dB relative to the wireless input. RESULTS: Speech scores for microphone with Ponto Pro and for both input modes of the Ponto Plus processor were essentially equal when equal input levels of wireless and microphone inputs were used. Only the TV-condition showed a statistically significant (p <5%) lower speech reception threshold for wireless relative to microphone input. In real life, evaluation of speech quality, speech intelligibility in quiet and noise, and annoyance by ambient noise, when using landline phone, mobile telephone, and watching TV showed a clear preference (p <1%) for the Ponto Plus system with streamer over the microphone input. Due to the small number of respondents with landline phone (N = 7) the result for noise annoyance was only significant at the 5% level. CONCLUSION: Equal input levels for acoustic and wireless inputs results in equal speech scores, showing a (near) equivalence for acoustic and wireless sound transmission with Ponto Pro and Ponto Plus. The default 9-dB difference between microphone and wireless input when using the telephone results in a substantial wireless benefit when using the telephone. The preference of wirelessly transmitted audio when watching TV can be attributed to the relatively poor sound quality of backward facing loudspeakers in flat screen TVs. The ratio of wireless and acoustic input can be easily set to the user's preference with the streamer's volume control.

Evaluation of a new powerful bone-anchored hearing system: a comparison study.

BACKGROUND: The recent introduction of digital hearing aid technology for bone-conduction devices employing percutaneous stimulation may be beneficial for patients with conductive and mixed hearing loss and single sided deafness. PURPOSE: Performance of a recently released sound processor for bone-anchored implants, the Ponto Pro Power from Oticon Medical (bone-conduction device 2 [BCD2]), was compared with that of the Baha Intenso from Cochlear (bone-conduction device 1 [BCD1]). RESEARCH DESIGN: Direct comparison of the subject's own device (BCD1) with the new device (BCD2) was examined in a nonrandomized design. Subjects were initially tested with BCD1. BCD2 was tested after a 4 wk acclimatization period. STUDY SAMPLE: Eighteen subjects with mixed hearing loss and with at least 4 mo experience with BCD1 completed the study. Mean air-conduction and bone-conduction thresholds averaged across the frequencies of 500, 1000, 2000, and 4000 Hz were 73.9 and 34.2 dB HL, respectively. DATA COLLECTION AND ANALYSIS: Performance of the two devices was evaluated objectively by measuring aided free-field thresholds, speech perception in quiet, and speech perception in noise. A subjective evaluation was carried out with the Abbreviated Profile of Hearing Aid Benefit (APHAB) (Cox and Alexander, 1995) and the Speech, Spatial and Qualities of Hearing Scale (SSQ) questionnaire (Gatehouse and Noble, 2004). In addition, user experiences, user satisfaction, and device preference were obtained via proprietary questionnaires. Statistical significance was established with analysis-of-variance (ANOVA) and paired t-statistics with Bonferroni correction. RESULTS: Aided free-field thresholds and speech reception thresholds (SRTs) in quiet were not statistically significantly different for either device (p > 0.05). In contrast, SRTs in noise were 2.0 dB lower (p < 0.001) for BCD2 than for BCD1. APHAB questionnaire scores on all subscales provided statistically significantly greater benefit (p < 0.05) for BCD2 than for BCD1. Also, with the SSQ most items in the speech and sound quality domain were significantly more favorable (p < 0.05) for BCD2 than for BCD1. Finally, all subjects preferred BCD2 over BCD1 with 14 subjects reporting a strong preference and four subjects an average preference for the digital signal processing provided by BCD2 over previous technology provided by BCD1.

Comparison of sound processing strategies for osseointegrated bone conduction implants in mixed hearing loss: multiple-channel nonlinear versus single-channel linear processing.

OBJECTIVES: Evaluation of a single-channel linear bone conduction implant sound processor (S-BCI) and a multiple-channel nonlinear bone conduction implant sound processor (M-BCI) with objective and subjective measures in patients with mixed hearing loss. STUDY DESIGN: In total, 20 patients with mixed hearing loss were included in the study. For either sound processor aided thresholds and speech perception in quiet with monosyllables were measured. Speech perception in noise was measured with sentences. Two different configurations were used: speech and noise at 0° (S0N0) and speech at 0° and noise at 180° (S0N180). The M-BCI was tested in both omnidirectional and directional mode. Patients were first fitted with the S-BCI and evaluated 3 weeks later. The M-BCI was fitted and, again 3 weeks later, evaluated. Subjectively, patients compared both sound processors with the APHAB questionnaire. RESULTS: Aided thresholds were similar for both sound processors in the low- and mid-frequency range. For speech in quiet, no significant differences between both sound processors were observed. For speech in noise in the S0N0 condition, the M-BCI-thresholds were 1.7 dB (SD, 2.2dB; p = 0.002) more favorable than with S-BCI. For the S0N180 configuration, an improvement of 5.8 dB (SD, 2.8 dB; p < 0.001) was seen for the directional mode relative to S-BCI. The APHAB showed statistically significant subjective improvement with the M-BCI on all subscales relative to S-BCI. CONCLUSION: Speech intelligibility in noise is better with M-BCI than with S-BCI. This was attributed to better high-frequency gain provided by the M-BCI. Improved signal processing strategies may have contributed to subjective preference for the M-BCI.

Bone-anchored hearing aids in patients with acquired and congenital unilateral inner ear deafness (Baha CROS): clinical evaluation of 56 cases.

OBJECTIVES: We performed an evaluation of the audiological and subjective benefits of the bone-anchored hearing aid (Baha) as a device for transcranial routing of sound (Baha CROS) in 56 patients with unilateral inner ear deafness. METHODS: We performed a prospective clinical follow-up study in a tertiary referral center. Previously reported results of 29 patients were supplemented with a second series of 30 patients with unilateral inner ear deafness; 3 patients dropped out during the evaluation. Audiometric measurements were taken before and after Baha CROS fitting. Subjective benefits were quantified with 4 different patient questionnaires. RESULTS: The sound localization results in a well-structured test setting were not differentiable from chance. The 5 patients with congenital hearing loss showed better scores in the unaided sound localization measurements. Overall, most patients reported some subjective improvement in their capacity to localize sounds with the Baha CROS in daily life. The main effect of the Baha CROS was to alleviate the head shadow effect during the speech-in-noise test. CONCLUSIONS: Poor sound localization in this larger series of patients confirms the findings of previous studies. Improvements in the speech-in-noise scores corroborated the efficacy of the Baha CROS in alleviating the head shadow effect. The 4 different patient questionnaires revealed subjective benefit and satisfaction in various domains.

Fitting range of the BAHA Intenso.

Audiometric characteristics of a recently introduced more powerful, behind-the-ear, BAHA sound processor, the BAHA Intenso, were evaluated in 23 patients with contra-indications for using conventional hearing aids. All patients had mixed hearing loss with boneconduction thresholds ranging between 30 and 50 dB HL. Boneconduction gain, defined as the difference in aided free-field detection thresholds and unaided boneconduction thresholds, was calculated at the octave frequencies between 500 Hz and 4 kHz. Median boneconduction gain of the Intenso ranges from 0 dB at 500 ;Hz to 12 ;dB at 2 kHz with substantial interindividual variability. The upper limit of the BAHA Intenso's fitting range was established by requiring aided speech reception thresholds with CVC-monosyllables of at most 60 dB SPL. The fitting range of the BAHA Intenso appeared to be limited to 42, 44, 58, and 48 dB HL for boneconduction thresholds at 0.5, 1, 2, and 4 ;kHz, respectively. Loudness growth functions at 0.5 and 3 kHz as obtained with 7-point categorical scaling showed an adequate aided dynamic range.

Audiometric characteristics of USH2a patients.

Temporal processing, frequency discrimination and frequency resolution, three basic mechanisms involved in speech perception, were studied in 11 USH2a patients from 10 Dutch families. Measurements included loudness scaling, gap detection, determination of auditory filter shapes and difference limen for frequency. The results were compared to values obtained from listeners with normal hearing, DFNA8/12 patients, DFNA13 patients and unselected patients with presbyacusis. Overall, the results for USH2a were most similar to those obtained in patients with sensorineural hearing loss caused by hair cell defects. To our knowledge, this is the first study that presents results on audiometric measurements combined with psychophysical measurements in a group of USH2a patients.

Audiological evaluation of affected members from a Dutch DFNA8/12 (TECTA) family.

In DFNA8/12, an autosomal dominantly inherited type of nonsyndromic hearing impairment, the TECTA gene mutation causes a defect in the structure of the tectorial membrane in the inner ear. Because DFNA8/12 affects the tectorial membrane, patients with DFNA8/12 may show specific audiometric characteristics. In this study, five selected members of a Dutch DFNA8/12 family with a TECTA sensorineural hearing impairment were evaluated with pure-tone audiometry, loudness scaling, speech perception in quiet and noise, difference limen for frequency, acoustic reflexes, otoacoustic emissions, and gap detection. Four out of five subjects showed an elevation of pure-tone thresholds, acoustic reflex thresholds, and loudness discomfort levels. Loudness growth curves are parallel to those found in normal-hearing individuals. Suprathreshold measures such as difference limen for frequency modulated pure tones, gap detection, and particularly speech perception in noise are within the normal range. Distortion otoacoustic emissions are present at the higher stimulus level. These results are similar to those previously obtained from a Dutch DFNA13 family with midfrequency sensorineural hearing impairment. It seems that a defect in the tectorial membrane results primarily in an attenuation of sound, whereas suprathreshold measures, such as otoacoustic emissions and speech perception in noise, are preserved rather well. The main effect of the defects is a shift in the operation point of the outer hair cells with near intact functioning at high levels. As most test results reflect those found in middle-ear conductive loss in both families, the sensorineural hearing impairment may be characterized as a cochlear conductive hearing impairment.

Fitting range of the BAHA Cordelle.

The performance of the most powerful Bone-Anchored Hearing Aid (BAHA) currently available, the BAHA Cordelle, was evaluated in 25 patients with severe to profound mixed hearing loss. Patients showed bone conduction thresholds at 500, 1000 and 2000 Hz, ranged between 30 and 70 dB HL, and an additional air-bone gap of about at least 30 dB. With the BAHA Cordelle, free-field thresholds improve relative to bone-conduction thresholds with 1.5, 5.0, 17.8, and 4.3 dB at 500, 1000, 2000, and 4000 Hz, respectively, with substantial inter-individual variability. The differences in unaided air conduction thresholds and aided free-field thresholds amount to 45.3, 45.8, 47.5, and 43.5 dB at 500, 1000, 2000, and 4000 Hz, respectively. Speech perception, measured both with monosyllables of the consonant-vowel-consonant type and with bisyllables, showed highly similar results. The fitting range of a (linear) hearing aid is determined by its gain characteristics. Requiring aided speech reception thresholds at or better than 65 dB SPL results in an upper limit of the fitting range of the BAHA Cordelle for bone-conduction thresholds of 51, 56, 67, and 58 dB HL at 500, 1000, 2000, and 4000 Hz, respectively. The dynamic range provided by the BAHA Cordelle was estimated from loudness growth functions at 500, 1500, and 3000 Hz employing 7-point categorical scaling. On average, aided loudness growth functions exhibit normal slopes but they level off at input levels of about 80, 70, 65 dB SPL for 500, 1500, and 3000 Hz stimuli, respectively. Measurements with a skull simulator demonstrated that the levelling-off reflects saturation of the output of the Cordelle. The relatively low saturation levels of the device suggest that increasing maximum output levels may be a worthwhile consideration for candidates with more profound sensorineural loss.