Cochlear Implantation for Unilateral and Asymmetric Hearing Loss: Long-Term Subjective Benefit.

OBJECTIVES: Assess the long-term patterns of perceived tinnitus severity and subjective benefit for adult cochlear implant (CI) users with asymmetric or unilateral hearing loss (AHL or UHL). METHODS: Forty adults underwent cochlear implantation as part of a prospective clinical trial assessing the outcomes of CI use in cases of AHL (n = 20) and UHL (n = 20). Subjective measures included the Tinnitus Handicap Inventory (THI), the Speech, Spatial, & Qualities of Hearing Scale (SSQ), and the Abbreviated Profile of Hearing Aid Benefit (APHAB). Responses were obtained preoperatively and at routine intervals out to 5 years post-activation. RESULTS: For subjective benefit, participants with AHL and UHL reported a significant improvement as compared to preoperative abilities, which was maintained with long-term CI use. For perceived tinnitus severity, participants with AHL and UHL reported a significant reduction with CI use as compared to preoperative perceptions. The perceived tinnitus severity significantly differed for the AHL and UHL cohorts over time. This pattern of results is likely influenced by the worse perceived severity levels for the UHL cohort preoperatively and the fluctuating perceived severity levels for some participants in the AHL cohort post-activation. CONCLUSION: Adults with AHL and UHL report an early, significant reduction in perceived tinnitus severity and improvement in quality of life with CI use that is generally maintained with long-term device use. Questionnaires such as the THI, SSQ, and APHAB may contribute to a more holistic assessment of the benefits of cochlear implantation in this population. LEVEL OF EVIDENCE: 2 Laryngoscope, 133:2792-2797, 2023.

Rehabilitation for unilateral deafness - Narrative review comparing a novel bone conduction solution with existing options.

Patients with single sided deafness (SSD) struggle with sound localization and speech in noise. Existing treatment options include contralateral routing of signal (CROS) systems, percutaneous bone conduction hearing devices (BCHDs), passive transcutaneous BCHDs, active BCHDs, and cochlear implants. Implanted devices provide benefits in speech in noise compared to CROS devices. Percutaneous BCHDs transmit sound efficiently but have aesthetic drawbacks and skin complications. Scalp attenuation impacts passive transcutaneous BCHD performance. Active BCHDs overcome these issues and provide benefits for speech in noise. Cochlear implantation is the only existing option that restores binaural input but introduces electrical rather than acoustic stimuli to the deaf ear. Active BCHDs have been designed to maintain efficient sound transmission and avoid chronic skin irritation and cosmetic concerns that may occur with percutaneous BCHDs. Cochlear implantation may be a superior option for recently deafened SSD patients, though this requires further study. The duration of deafness, patient age and comorbidities, and a shared decision-making model among patients, surgeons, and audiologists should be considered in device selection. The aim of this manuscript is to review available devices, discuss surgical considerations for implantable devices, review available published results for speech in noise and sound quality with each device, and provide an overview to guide shared decision making for patients and providers. This review consolidates available literature and reviews experience with a newer active transcutaneous active BCHD available for use in the SSD population.

Evaluating the Decision for Cochlear Implantation in Individuals With Single-Sided Deafness (SSD); Implementing the SSD Consensus Protocol Into Clinical Routine.

OBJECTIVE: To implement a unified testing framework into clinical routine that can be used by adults with single-sided deafness (SSD) to assess alternative treatment options before cochlear implantation. STUDY DESIGN: Retrospective data analysis. SETTING: Tertiary referral center with a large CI program. SUBJECTS AND METHODS: Thirty four participants underwent the new implemented testing procedure, including a test trial with contralateral routing of the signal (CROS) hearing aids and bone conduction devices (BCD) on a headband, before deciding whether to proceed with cochlear implantation. A test battery was used to assess speech in noise, binaural effects (head shadow, squelch, summation, spatial release from masking), sound localization, and quality of life. For participants that chose a CI, the same test battery was repeated during the 6 and 12 months follow-up appointments. RESULTS: Of the 34 participants involved in the study, 11 were implanted with a CI and finished their 12 month evaluation. Sixteen participants decided to stop after the CROS/BCD trial. In the CI-recipient group, a significant head shadow effect of 5.1 to 7.1 dB was achieved with the CI. Recipients in this group received only a limited benefit with either CROS or BCD before implantation. In the non-CI-recipient group, a significant difference between the CROS and BCD, in favor for the CROS device, was found calculating the head shadow and squelch effect. Localization abilities with the CI improved significantly in the CI-recipient group, even between the 6- and 12-month follow-up appointments. In the non-CI-recipient group, localization was significantly better with the BCD during the trial period. Higher scores were obtained from the speech and spatial categories of the Speech, Spatial, and Qualities of Hearing (SSQ) questionnaire with the CI. No subjective difference could be determined in the non-CI-recipient group. CONCLUSION: Implementing the unified testing framework into a clinical routine was challenging but provided helpful insight into the best treatment option for each individual.

Neural Substrates of Tinnitus in an Auditory Brainstem Implant Patient: A Preliminary Molecular Imaging Study Using H2 15 O-PET Including a 5-year Follow-up of Auditory Performance and Tinnitus Perception.

INTRODUCTION: It was previously demonstrated that tinnitus due to profound unilateral hearing loss can be treated by the use of electrical stimulation via a cochlear implant (CI) with long-lasting positive effects. In cases where patients are not suitable for cochlear implantation due to aplasia/hypoplasia, cochlear malformations etc., an auditory brainstem implant (ABI) may be a solution. While auditory performance with ABI is well investigated, it is currently unknown whether stimulation through ABI also renders tinnitus reduction in patients with incapacitating tinnitus. The current case study reports on the subjective tinnitus perception during a 5-year follow-up period. In addition, a first H2O PET imaging study in an ABI patient is carried out revealing underlying neural substrates of tinnitus. METHODS: A 56-year-old male single-sided deaf patient with incapacitating tinnitus received an ABI after insufficient auditory performances and only minor tinnitus reduction with CI. Audiological follow-up was carried out during a 5-year follow-up period comprising pure-tone audiometry, speech-in-quiet testing, speech-in-noise testing, tinnitus questionnaires (tinnitus questionnaire and numeric rating scale) and the HISQUI19 questionnaire. To investigate the neural substrates of tinnitus in this subject, H2O PET tomography scans were acquired in three different conditions: 1) ABI switched off which was considered as the resting-state measurement rendering the loudest possible tinnitus for the patient (ABI OFF); 2) ABI switched on causing a small suppression of tinnitus due to electrical stimulation (ABI ON); 3) ABI switched on and 70 dB SPL white noise presented directly to the external audio processor through a direct audio cable providing the maximum tinnitus suppression for the patient (NOISE). RESULTS: Subjectively the patient reported a significant tinnitus reduction after implantation which remained stable over time with a decrease in tinnitus questionnaire from grade 4 to grade 2 and a 50% reduction in the numeric rating scale (from 8 to 4) during the 5-year period. Comparing the ABI OFF and ABI ON conditions, significant increase in regional cerebral blood flow (rCBF) was observed in brain areas involved in the salience network showing already suppression of tinnitus only by electrical stimulation in the absence of auditory stimuli. The NOISE condition showed relatively decreased rCBF in the insula (as well as in the orbitofrontal cortex) as compared with the ABI OFF condition. Abnormally activated areas comprising the salience network may have been significantly suppressed by the NOISE condition both by acoustic and electrical stimulations of the auditory pathway. Moreover, the NOISE condition showed significantly decreased rCBF in the parahippocampus as compared with the ABI OFF condition. This finding supports the idea of distinct tinnitus generators depending on the amount of hearing loss. CONCLUSION: The reduction of tinnitus in the current ABI subject may be attributable to partial peripheral reafferentation-induced deactivation of the parahippocampus-based tinnitus generator as well as the salience network. Further validation is required by the use of a follow-up study with a larger number of subjects.

Low-Frequency Pitch Perception in Cochlear Implant Recipients With Normal Hearing in the Contralateral Ear.

Purpose Three experiments were carried out to evaluate the low-frequency pitch perception of adults with unilateral hearing loss who received a cochlear implant (CI). Method Participants were recruited from a cohort of CI users with unilateral hearing loss and normal hearing in the contralateral ear. First, low-frequency pitch perception was assessed for the 5 most apical electrodes at 1, 3, 6, and 12 months after CI activation using an adaptive pitch-matching task. Participants listened with a coding strategy that presents low-frequency temporal fine structure (TFS) and compared the pitch to that of an acoustic target presented to the normal hearing ear. Next, participants listened with an envelope-only, continuous interleaved sampling strategy. Pitch perception was compared between coding strategies to assess the influence of TFS cues on low-frequency pitch perception. Finally, participants completed a vocal pitch-matching task to corroborate the results obtained with the adaptive pitch-matching task. Results Pitch matches roughly corresponded to electrode center frequencies (CFs) in the CI map. Adaptive pitch matches exceeded the CF for the most apical electrode, an effect that was larger for continuous interleaved sampling than TFS. Vocal pitch matches were variable but correlated with the CF of the 3 most apical electrodes. There was no evidence that pitch matches changed between the 1- and 12-month intervals. Conclusions Relatively accurate and asymptotic pitch perception was observed at the 1-month interval, indicating either very rapid acclimatization or the provision of familiar place and rate cues. Early availability of appropriate pitch cues could have played a role in the early improvements in localization and masked speech recognition previously observed in this cohort. Supplemental Material https://doi.org/10.23641/asha.8862389.

Binaural advantages in using a cochlear implant for adults with profound unilateral hearing loss.

BACKGROUND: Recent studies of cochlear implants (CIs) in profound unilateral hearing loss (UHL) patients have demonstrated a restoration of some binaural hearing. AIMS/OBJECTIVES: The objective was to evaluate three possible advantages of binaural hearing in CIs adult users with UHL including single-side deafness (SSD) and asymmetric hearing loss (AHL) subgroups. MATERIAL AND METHODS: A prospective study was conducted that included 70 sequentially implanted patients. Subgroups of these subjects included 64 with a postlingual onset of a profound hearing loss on the implanted side and 6 with a prelingual onset of that loss. Three binaural effects - redundancy, head shadow, and squelch - were evaluated. RESULTS: Significant differences between the 'CI on' and 'CI off' conditions were found for all three binaural effects for the study group as a whole and for the postlingual subgroup. However, results for the subjects in the prelingual subgroup did not demonstrate any of the binaural advantages. CONCLUSION AND SIGNIFICANCE: Patients with a postlingual onset of a profound hearing loss in one ear and normal hearing or only a moderate loss in the other ear are able to make the effective use of a CI in the profound-loss ear in conjunction with acoustic stimulation of the other ear.

Long-term results of partial deafness treatment.

Treatment of the partial deafness is a great challenge in terms of preserving the preoperative hearing and complementing this hearing ability with an implant. It concerns the situations when hearing in low frequency range is normal or fully functional and it is only necessary to complement it electrically in the medium and high frequency ranges. The first in the world surgery during which an existing normal hearing had been electrically complemented was performed in 2002. It has shown a fresh direction in treatment of various partial hearing impairments. This achievement was possible due to our previous works on hearing preservation in the group of patients with marginal residual hearing. The long term observation (almost 15 years) and large material allow us to present the strategy of the partial deafness treatment and its results. During the ESPCI conference in Warsaw in 2009, PDT concept was announced, indicating groups for Acoustic Stimulation (AS) and Electric Stimulation (ES). ES patients can be divided on the following groups: Electrical Complement (PDT-EC), Electric Acoustic Stimulation (PDT-EAS), Electric Modified Stimulation (PDT-EMS), Electric Stimulation (PDT-ES). The differentiation between the groups is very important, because the groups are not equal and their goals in treatment and therapy are different. Concluding we can say that hearing was preserved in over 94% of cases, however, the results differ between the groups. Implementation of the partial deafness treatment (PDT) is connected with development and elaboration of special rehabilitation program for the specific groups of patients.

The benefits of bimodal hearing: effect of frequency region and acoustic bandwidth.

We examined the effects of acoustic bandwidth on bimodal benefit for speech recognition in adults with a cochlear implant (CI) in one ear and low-frequency acoustic hearing in the contralateral ear. The primary aims were to (1) replicate Zhang et al. [Ear Hear 2010;31:63-69] with a steeper filter roll-off to examine the low-pass bandwidth required to obtain bimodal benefit for speech recognition and expand results to include different signal-to-noise ratios (SNRs) and talker genders, (2) determine whether the bimodal benefit increased with acoustic low-pass bandwidth and (3) determine whether an equivalent bimodal benefit was obtained with acoustic signals of similar low-pass and pass band bandwidth, but different center frequencies. Speech recognition was assessed using words presented in quiet and sentences in noise (+10, +5 and 0 dB SNRs). Acoustic stimuli presented to the nonimplanted ear were filtered into the following bands: <125, 125-250, <250, 250-500, <500, 250-750, <750 Hz and wide-band (full, nonfiltered bandwidth). The primary findings were: (1) the minimum acoustic low-pass bandwidth that produced a significant bimodal benefit was <250 Hz for male talkers in quiet and for female talkers in multitalker babble, but <125 Hz for male talkers in background noise, and the observed bimodal benefit did not vary significantly with SNR; (2) the bimodal benefit increased systematically with acoustic low-pass bandwidth up to <750 Hz for a male talker in quiet and female talkers in noise and up to <500 Hz for male talkers in noise, and (3) a similar bimodal benefit was obtained with low-pass and band-pass-filtered stimuli with different center frequencies (e.g. <250 vs. 250-500 Hz), meaning multiple frequency regions contain useful cues for bimodal benefit. Clinical implications are that (1) all aidable frequencies should be amplified in individuals with bimodal hearing, and (2) verification of audibility at 125 Hz is unnecessary unless it is the only aidable frequency.

On the necessity of full length electrical cochlear stimulation to suppress severe tinnitus in single-sided deafness.

BACKGROUND: Cochlear implantation (CI) has proven in long term prospective trials to reduce significantly incapacitating tinnitus in single sided deafness (SSD). Discussion arises whether electrical stimulation near the round window (RW) is also able to reduce tinnitus. AIM: to assess whether electrical stimulation of the basal first 4 intracochlear electrodes of a CI could sufficiently reduce tinnitus and to compare these results with stimulation with all CI electrodes. MATERIAL AND METHODS: 7 patients who met the criteria of severe tinnitus due to SSD were implanted with a Med-El Sonata Ti100 with a FlexSoftTM or Flex24TM electrode. After 4 weeks only the basal electrode pair (E12) nearest to the RW was activated. Each week the following pair was activated until the 4th pair.Thereafter all electrodes were activated. Tinnitus was assessed before CI surgery and before each electrode pair was activated. When all electrodes were fitted, evaluation was done after 1, 3 and 6 months.Tinnitus was assessed with Visual Analogue Scale (VAS) for loudness, psychoacoustic tinnitus loudness comparison at 1 kHz and Tinnitus Questionnaire (TQ) for the effect on quality of life. To evaluate the natural evolution, a tightly matched control group with severe tinnitus due to SSD was followed prospectively. RESULTS: All the tinnitus outcome measures remained unchanged with 1, 2, 3 or 4 activated electrode pairs. With complete CI activation, the tinnitus decreased significantly comparable with earlier reports.Pre-implantation the tinnitus loudness was 8.2/10 on the VAS and was reduced to 4.1/10 6 months postimplantation.Psychometrically the loudness level went from 21.7 dB SL (SD: 16.02) to 7.5 dB SL (SD: 5.24)and the TQ from 60/84 to 39/84. The non-implanted group had no decrease of the tinnitus, the average VAS remained stable at 8.9/10 throughout the follow-up period of 6 months. CONCLUSION: with the current stimulation parameters electrical stimulation in the first 8e10 mm of the basal part of the scala tympani is insufficient to reduce tinnitus. However, stimulation over the complete CI length yields immediate tinnitus reduction confirming earlier results.

Comparison of pseudobinaural hearing to real binaural hearing rehabilitation after cochlear implantation in patients with unilateral deafness and tinnitus.

OBJECTIVE: Up to now, treatment modalities of unilateral deafness consist of no treatment, conventional contralateral routing of signal (CROS), or Bone-Anchored Hearing Aid (BAHA) hearing aid. Cochlear implantation makes a new treatment modality available for patients with single-sided deafness. The aim of this study is to evaluate the use of unilateral electrical stimulation with normal hearing on the contralateral side after a period of 6 months compared with the preoperative unaided situation, conventional CROS, or BAHA hearing aids. STUDY DESIGN: Prospective design. SETTING: Tertiary referral center; cochlear implant (CI) program. PATIENTS: Eleven adult subjects with unilateral deafness of various causes were enrolled in the study. Only those patients were included in whom therapy with CROS hearing aid or BAHA was not successful and in whom the auditory nerve was found to be intact and the cochlea patent for cochlear implantation. INTERVENTION: All subjects were fitted in random order with a BAHA Intenso mounted on the softband/tension clamp or with a CROS hearing aid. After test periods with both devices, the subjects received a CI. MAIN OUTCOME MEASURES: The Hochmair-Schulz-Moser sentence test and the Oldenburg sentence test were used to test speech comprehension in 3 presentation configurations in the unaided situation, with conventional CROS and BAHA hearing aids before cochlear implantation as well as after 6 months with CI. Localization was assessed using an array of 7 speakers at head level in a frontal semicircle. Subjective improvement in daily life was evaluated using the Speech, Spatial and Qualities of Hearing Scale, the Health Utilities Index 3 and the International Outcome Inventory for Hearing Aids questionnaires. Tinnitus distress was measured with a tinnitus scale before and after CI implantation. RESULTS: The results show significant improvement in localization ability as well as in speech comprehension in most presentation configurations with the CI. Especially, there is no negative effect on speech comprehension if the noise is presented to the CI ear and speech to the normal hearing ear. With the CI, the summation and squelch effects are not significant, but a significant combined head shadow effect is seen. Speech, Spatial and Qualities of Hearing results show an overall benefit of wearing the CI compared with the other treatment options. The tinnitus scale revealed a positive effect of CI stimulation in cases of preoperative tinnitus. CONCLUSION: The results in these patients suggest that cochlear implantation improves hearing abilities in people with single-sided deafness and is superior to the alternative treatment options. The use of the CI does not interfere with speech understanding in the normal hearing ear. Our data suggest that the binaural integration of electric and acoustic stimulation is possible even with unilateral normal hearing.

Partial deafness cochlear implantation in children.

OBJECTIVE: Partial deafness cochlear implantation and electric-acoustic stimulation have proven to be a useful method of treating adults with a ski-slope type hearing loss. Good hearing preservation and speech perception outcomes have been reported. This study aims to assess partial deafness cochlear implantation in children. METHOD: Nine children, ranging in age from 4.2 to 12 years, received a cochlear implant following the round window surgical technique for partial deafness cochlear implantation. Hearing preservation was assessed by pure-tone audiometry and speech perception outcomes were measured using monosyllable word tests in quiet and noise. Data are available for most children up to a period of 1 year. RESULTS: Hearing could be preserved partially in all cases, however, one child does not have sufficient preservation to make use of electric-acoustic stimulation. The eight children with sufficiently preserved hearing either use the natural low frequency hearing in combination with a cochlear implant to hear or use the DUET combined hearing system. Speech perception tests showed improvement in quiet and noise over time. CONCLUSION: Results suggest that partial deafness cochlear implantation is a viable treatment method in children. However, surgery should only be conducted by an experienced surgeon and parents need to be carefully counselled about the risks and benefits of partial deafness cochlear implantation.