Clinical implications of a damaged cochlea: pure tone thresholds vs information-carrying capacity

Outcome Prediction of Speech Perception in Quiet and in Noise for Cochlear Implant Candidates Based on Pre-Operative Measures

(1) Background: The fitting of cochlear implants (CI) is an established treatment, even in cases with considerable residual hearing but insufficient speech perception. The aim of this study was to evaluate a prediction model for speech in quiet and to provide reference data and a predictive model for postoperative speech perception in noise (SPiN) after CI provision. (2) Methods: CI candidates with substantial residual hearing (either in hearing threshold or in word recognition scores) were included in a retrospective analysis (n = 87). Speech perception scores in quiet 12 months post-surgery were compared with the predicted scores. A generalized linear model was fitted to speech reception thresholds (SRTs) after CI fitting to identify predictive variables for SPiN. (3) Results: About two-thirds of the recipients achieved the expected outcome in quiet or were better than expected. The mean absolute error of the prediction was 13.5 percentage points. Age at implantation was the only predictive factor for SPiN showing a significant correlation (r = 0.354; p = 0.007). (4) Conclusions: Outcome prediction accuracy for speech in quiet was comparable to previous studies. For CI recipients in the included study population, the SPiN outcome could be predicted only based on the factor age.

Extended Preoperative Audiometry for Outcome Prediction and Risk Analysis in Patients Receiving Cochlear Implants

BACKGROUND

The outcome of cochlear implantation has improved over the last decades, but there are still patients with less benefit. Despite numerous studies examining the cochlear implant (CI) outcome, variations in speech comprehension with CI remains incompletely explained. The aim of this study was therefore to examine preoperative pure-tone audiogram and speech comprehension as well as aetiology, to investigate their relationship with postoperative speech comprehension in CI recipients.

METHODS

A retrospective study with 664 ears of 530 adult patients was conducted. Correlations between the target variable postoperative word comprehension with the preoperative speech and sound comprehension as well as aetiology were investigated. Significant correlations were inserted into multivariate models. Speech comprehension measured as word recognition score at 70 dB with CI was analyzed as (i) a continuous and (ii) a dichotomous variable.

RESULTS

All variables that tested preoperative hearing were significantly correlated with the dichotomous target; with the continuous target, all except word comprehension at 65 dB with hearing aid. The strongest correlation with postoperative speech comprehension was seen for monosyllabic words with hearing aid at 80 dB. The preoperative maximum word comprehension was reached or surpassed by 97.3% of CI patients. Meningitis and congenital diseases were strongly negatively associated with postoperative word comprehension. The multivariate model was able to explain 40% of postoperative variability.

CONCLUSION

Speech comprehension with hearing aid at 80 dB can be used as a supplementary preoperative indicator of CI-aided speech comprehension and should be measured regularly in the clinical routine. Combining audiological and aetiological variables provides more insights into the variability of the CI outcome, allowing for better patient counselling.

Role of cochlear reserve in adults with cochlear implants following post-lingual hearing loss

INTRODUCTION

Pre-operative assessments before cochlear implantation (CI) includes the examination of both tone hearing, and the level of the cochlear reserve indicated by speech understanding. The goal of this study was to explore the predictive influence of tone hearing and cochlear reserve in CI.

METHODS

We did a retrospective cohort study, which included adult patients who had undergone CI between January 2012 and December 2019 in a tertiary care center. The pre-operative tone hearing, unaided maximum monosyllabic word recognition score (WRSmax), aided hearing gain, aided monosyllabic word recognition score at 65 dB (WRS65(HA)), and speech perception gap (SPG) were measured. The duration of unaided hearing loss (UHL) was also assessed. These variables were compared with post-operative monosyllabic word recognition score after CI at 65 dB (WRS65(CI)).

RESULTS

103 patients and 128 ears were included in this study. Regardless of tone hearing, patients with better pre-operative WRSmax and WRS65(HA) performed better post-operatively. WRSmax was found to be the most important factor that was statistically significantly associated with WRS65(CI). SPG was statistically significantly associated with WRSmax and SPG ≥ 20% group performed better post-operatively. Any duration of unaided hearing loss was statistically significantly inversely associated with WRSmax above 0%.

CONCLUSION

Cochlear reserve represented by WRSmax may play the most important role as a predictive factor in outcomes after CI. SPG should be considered for indicating CI in patients, when WRS65(HA) does not reach WRSmax. Early rehabilitation with hearing aids and duration of hearing aid usage might play an important role in preserving cochlear reserve in adults.

Guidelines for Best Practice in the Audiological Management of Adults Using Bimodal Hearing Configurations

Clinics are treating a growing number of patients with greater amounts of residual hearing. These patients often benefit from a bimodal hearing configuration in which acoustic input from a hearing aid on 1 ear is combined with electrical stimulation from a cochlear implant on the other ear. The current guidelines aim to review the literature and provide best practice recommendations for the evaluation and treatment of individuals with bilateral sensorineural hearing loss who may benefit from bimodal hearing configurations. Specifically, the guidelines review: benefits of bimodal listening, preoperative and postoperative cochlear implant evaluation and programming, bimodal hearing aid fitting, contralateral routing of signal considerations, bimodal treatment for tinnitus, and aural rehabilitation recommendations.

Animal models of hidden hearing loss: Does auditory-nerve-fiber loss cause real-world listening difficulties?

Afferent innervation of the cochlea by the auditory nerve declines during aging and potentially after sound overexposure, producing the common pathology known as cochlear synaptopathy. Auditory-nerve-fiber loss is difficult to detect with the clinical audiogram and has been proposed to cause 'hidden hearing loss' including impaired speech-in-noise perception. While evidence that auditory-nerve-fiber loss causes hidden hearing loss in humans is controversial, behavioral animal models hold promise to rigorously test this hypothesis because neural lesions can be induced and histologically validated. Here, we review recent animal behavioral studies on the impact of auditory-nerve-fiber loss on perception in a range of species. We first consider studies of tinnitus and hyperacusis inferred from acoustic startle reflexes, followed by a review of operant-conditioning studies of the audiogram, temporal integration for tones of varying duration, temporal resolution of gaps in noise, and tone-in-noise detection. Studies quantifying the audiogram show that tone-in-quiet sensitivity is unaffected by auditory-nerve-fiber loss unless neural lesions exceed 80%, at which point large deficits are possible. Changes in other aspects of perception, which were typically investigated for moderate-to-severe auditory-nerve-fiber loss of 50-70%, appear heterogeneous across studies and might be small compared to impairment caused by hair-cell pathologies. Future studies should pursue recent findings that behavioral sensitivity to brief tones and silent gaps in noise may be particularly vulnerable to auditory-nerve-fiber loss. Furthermore, aspects of auditory perception linked to central inhibition and fine neural response timing, such as modulation masking release and spatial hearing, may be productive directions for further animal behavioral research.

Predicting the Cochlear Dead Regions Using a Machine Learning-Based Approach with Oversampling Techniques

Background and Objectives: Determining the presence or absence of cochlear dead regions (DRs) is essential in clinical practice. This study proposes a machine learning (ML)-based model that applies oversampling techniques for predicting DRs in patients. Materials and Methods: We used recursive partitioning and regression for classification tree (CT) and logistic regression (LR) as prediction models. To overcome the imbalanced nature of the dataset, oversampling techniques to duplicate examples in the minority class or to synthesize new examples from existing examples in the minority class were adopted, namely the synthetic minority oversampling technique (SMOTE). Results: The accuracy results of the 10-fold cross-validation of the LR and CT with the original data were 0.82 (±0.02) and 0.93 (±0.01), respectively. The accuracy results of the 10-fold cross-validation of the LR and CT with the oversampled data were 0.66 (±0.02) and 0.86 (±0.01), respectively. Conclusions: This study is the first to adopt the SMOTE method to assess the role of oversampling methods on audiological datasets and to develop an ML-based model. Considering that the SMOTE method did not improve the model’s performance, a more flexible model or more clinical features may be needed.

Primary Neural Degeneration in Noise-Exposed Human Cochleas: Correlations with Outer Hair Cell Loss and Word-Discrimination Scores

Animal studies suggest that cochlear nerve degeneration precedes sensory cell degeneration in both noise-induced hearing loss (NIHL) and age-related hearing loss (ARHL), producing a hearing impairment that is not reflected in audiometric thresholds. Here, we investigated the histopathology of human ARHL and NIHL by comparing loss of auditory nerve fibers (ANFs), cochlear hair cells and the stria vascularis in a group of 52 cases with noise-exposure history against an age-matched control group. Although strial atrophy increased with age, there was no effect of noise history. Outer hair cell (OHC) loss also increased with age throughout the cochlea but was unaffected by noise history in the low-frequency region (<2 kHz), while greatly exacerbated at high frequencies (≥2 kHz). Inner hair cell (IHC) loss was primarily seen at high frequencies but was unaffected by noise at either low or high frequencies. ANF loss was substantial at all cochlear frequencies and was exacerbated by noise throughout. According to a multivariable regression model, this loss of neural channels contributes to poor word discrimination among those with similar audiometric threshold losses. The histopathological patterns observed also suggest that, whereas the low-frequency OHC loss may be an unavoidable consequence of aging, the high-frequency loss, which produces the classic down-sloping audiogram of ARHL, may be partially because of avoidable ear abuse, even among those without a documented history of acoustic overexposure.SIGNIFICANCE STATEMENT As regenerative therapeutics in sensorineural hearing loss enter clinical trials, it becomes critical to infer which cochlear pathologies are present in addition to hair cell loss. Here, by analyzing human autopsy material, we show that acoustic injury accelerates age-related primary neural degeneration, but not strial degeneration, neither of which can be inferred from audiometric thresholds. It exacerbates outer hair cell (OHC) loss only in the high-frequency half of the cochlea, suggesting that the apical loss is age-related, whereas the basal loss is partially noise induced, and therefore avoidable. Statistical analysis suggests that neural loss helps explain differences in word-recognition ability among individuals with similar audiometric thresholds. The surprising correlation between neural loss and OHC loss in the cochlea's speech region also implicates neural loss in the well-known decline in word scores as thresholds deteriorate with age.

Effect of Contralateral Noise on Speech Intelligibility

In patients with strong asymmetric hearing loss, standard clinical practice involves testing speech intelligibility in the ear with the higher hearing threshold by simultaneously presenting noise to the other ear. However, psychoacoustic and functional magnetic resonance imaging (fMRI) studies indicate that this approach may be problematic as contralateral noise has a disruptive effect on task processing. Furthermore, fMRI studies have revealed that the effect of contralateral noise on brain activity depends on the lateralization of task processing. The effect of contralateral noise is stronger when task-relevant stimuli are presented ipsilaterally to the hemisphere that is processing the task. In the present study, we tested the effect of four different levels of contralateral noise on speech intelligibility using the Oldenburg sentence test (OLSA). Cortical lateralization of speech processing was assessed upfront by using a visual speech test with fMRI. Contralateral OLSA noise of 65 or 80 dB SPL significantly reduced word intelligibility irrespective of which ear the speech was presented to. In participants with left-lateralized speech processing, 50 dB SPL contralateral OLSA noise led to a significant reduction in speech intelligibility when speech was presented to the left ear, i.e. when speech was presented ipsilaterally to the hemisphere that is mainly processing speech. Thus, contralateral noise, as used in standard clinical practice, not only prevents listeners from using the information in the better-hearing ear but may also have the unintended effect of hampering central processing of speech.

Speech recognition with hearing aids for 10 standard audiograms : English version

Background

Improvement of speech perception in quiet is an important goal of hearing aid provision. In practice, results are highly variable. The aim of this study was to investigate the relationship between type and extent of hearing loss (audiogram type), maximum word recognition score, and aided speech perception.

Materials and methods

Pure tone and speech audiometric data of 740 ears in 370 patients were reviewed. All subjects visited our hearing center for hearing aid evaluation between 2012 and 2017. The maximum word recognition score (WRS_max) and the monosyllabic speech recognition score with hearing aids, WRS₆₅(HA) were analyzed for 10 different standard audiogram types.

Results

The WRS₆₅(HA) with hearing aids for different degrees of hearing loss is, within error boundaries, comparable to previous investigations and shows a difference of 10–20 percentage points to the WRS_max. This difference tends to be larger for flat and moderately sloping audiograms compared to steep-sloping audiograms. The ratio WRS₆₅(HA)/WRS_max can be interpreted as an efficiency factor for hearing aid provision, since it relates speech recognition with hearing aids to the maximally achievable information carrying capacity of the hearing impaired.

Conclusion

The expectation regarding hearing aid provision has to be adjusted according to maximum word recognition score, the derived quality measures, degree of hearing loss, and audiogram type.

Influence of Cochlear Dead Regions on Hearing Outcome in Sudden Sensorineural Hearing Loss

OBJECTIVE

The aims of this multicenter study were to prospectively evaluate the prevalence of dead regions (DRs) in sudden sensorineural hearing loss (SSNHL) and compare the clinical characteristics and hearing outcomes of SSNHL according to the presence of DRs.

STUDY DESIGN

Prospective study.

SETTING

Multicenter study.

PATIENTS AND METHODS

The threshold-equalizing noise (TEN) test was prospectively performed on a total of 130 patients diagnosed with SSNHL. All patients received systemic steroid therapy and/or intratympanic steroid injection within 1 month after onset. Pure-tone audiograms and the TEN test were conducted before and after steroid treatment. Age, sex, side of affected ear, recurrence, onset of symptoms, presence of dizziness, and comorbid diseases were also collected. The prevalence of DRs in SSNHL and clinical factors related to the DRs were assessed. Hearing outcomes for SSNHL according to DRs were evaluated in 68 patients who followed a pure-tone audiogram.

RESULTS

The overall prevalence of one or more DRs in SSNHL evaluated using the TEN test was 20.8% (27/130 subjects) and the overall frequency-specific prevalence of DR was 6.7% (61/910 DRs). Although the DRs (+)and DR (-) groups had similar initial pure-tone thresholds, the DRs (+) group had significantly worse initial WRS compared to the DRs (-) group (p = 0.015). The presence of DRs was not associated with hearing recovery in a multivariate logistic regression model, but it was significantly associated with the degree of hearing gain in a multivariate linear regression model (p = 0.018).

CONCLUSIONS

The presence of DRs can be considered one of the poor prognostic factors for SSNHL and the TEN test may contribute to assess the prognosis of SSNHL in clinical settings.

Clinical Experience of Vibroplasty With Direct Coupling to the Oval Window Without Use of a Coupler

OBJECTIVES/HYPOTHESIS

To investigate the efficacy of direct implantation of a Vibrant Soundbridge (VSB) implant in the oval window (OW) without the use of an OW coupler in patients with severe mixed hearing loss.

STUDY DESIGN

Retrospective chart review METHODS: A total of 62 patients underwent VSB implantation between July 2016 and December 2018 at Severance Hospital in Seoul, South Korea. Among them, eight patients (nine ears) with moderate-to-severe mixed hearing loss were implanted with a VSB directly in the OW. A floating mass transducer (FMT) was attached to the stapes footplate and covered with tragal cartilage. The outcomes were evaluated using pure-tone audiogram and speech audiogram preoperatively and postoperatively. Word recognition score (WRS; % correct) were measured at the most comfortable loudness (MCL) level to evaluate speech perception.

RESULTS

All cases posed difficulty with round window vibroplasty during surgery, and eventually, an FMT was appropriately placed in the OW without a coupler. Preoperative and postoperative bone conduction thresholds were not different. VSB-aided threshold improved in terms of functional and effective gains. Interestingly, four cases showed improved air conduction thresholds without the use of a VSB. In addition, MCL level with a VSB was significantly lower than that with a hearing aid, and VSB-aided WRS improved over time.

CONCLUSIONS

Direct implantation of a VSB in the OW without the use of a coupler showed favorable hearing outcomes, and the OW vibroplasty was safe. Direct OW vibroplasty without a coupler is a reliable procedure and can be a good option for hearing rehabilitation in patients with severe mixed hearing loss.

LEVEL OF EVIDENCE

4 Laryngoscope, 2020.

[Speech recognition with hearing aids for 10 standard audiograms]

BACKGROUND

Improvement of speech perception in quiet is an important goal of hearing aid provision. In practice, results are highly variable. The aim of this study was to investigate the relationship between type and extent of hearing loss (audiogram type), maximum word recognition score, and aided speech perception.

MATERIALS AND METHODS

Pure tone and speech audiometric data of 740 ears in 370 patients were reviewed. All subjects visited our hearing center for hearing aid evaluation between 2012 and 2017. The maximum word recognition score (WRS_max) and the monosyllabic speech recognition score with hearing aids, WRS₆₅(HA) were analyzed for 10 different standard audiogram types.

RESULTS

The WRS₆₅(HA) with hearing aids for different degrees of hearing loss is, within error boundaries, comparable to previous investigations and shows a difference of 10-20 percentage points to the WRS_max. This difference tends to be larger for flat and moderately sloping audiograms compared to steep-sloping audiograms. The ratio WRS₆₅(HA)/WRS_max can be interpreted as an efficiency factor for hearing aid provision, since it relates speech recognition with hearing aids to the maximally achievable information carrying capacity of the hearing impaired.

CONCLUSION

The expectation regarding hearing aid provision has to be adjusted according to maximum word recognition score, the derived quality measures, degree of hearing loss, and audiogram type.

Direct Acoustic Cochlear Implants Lead to an Improved Speech Perception Gap Compared to Conventional Hearing Aid

OBJECTIVES

The objectives of this study was to evaluate the aided speech perception in quiet of direct acoustic cochlear implant (DACI) patients and the speech perception gap in comparison with hearing aid users.

STUDY DESIGN

Retrospective comparative study.

SETTING

Tertiary referral center.

PATIENTS

Adults with moderate-to-severe mixed hearing loss who have been implanted with a DACI and fitted with a processor for at least 6 months.

INTERVENTION(S)

Comparison of aided monosyllabic word scores and speech perception gap of 59 DACI-implanted ears speech perception gap with published data on 208 ears aided with a conventional hearing aid (HA) divided into four different hearing loss groups between 35 and 75 dB HL.

MAIN OUTCOME MEASURE(S)

Aided monosyllabic word score, predicted maximum monosyllabic word recognition score (PBmax) and speech perception gap.

RESULTS

In terms of aided speech perception, DACI patients with cochlear reserves between 45 and 65 dB HL have a significant advantage compared with conventional HA users. A speech perception gap of 11% points for DACI and 21% points for conventional HAs were determined and an approximation of PBmax is achieved by 52% of the DACI patients compared with only 36% of the HA users.

CONCLUSIONS

For patients with moderate-to-severe inner ear hearing loss between 45 and 65 dB HL, better speech perception in quiet is obtained with the DACI system. Compared with conventional hearing aids, speech performance with the DACI is closer to the maximally possibly score PBmax.

Divergent Auditory Nerve Encoding Deficits Between Two Common Etiologies of Sensorineural Hearing Loss

Speech intelligibility can vary dramatically between individuals with similar clinically defined severity of hearing loss based on the audiogram. These perceptual differences, despite equal audiometric-threshold elevation, are often assumed to reflect central-processing variations. Here, we compared peripheral-processing in auditory nerve (AN) fibers of male chinchillas between two prevalent hearing loss etiologies: metabolic hearing loss (MHL) and noise-induced hearing loss (NIHL). MHL results from age-related reduction of the endocochlear potential due to atrophy of the stria vascularis. MHL in the present study was induced using furosemide, which provides a validated model of age-related MHL in young animals by reversibly inhibiting the endocochlear potential. Effects of MHL on peripheral processing were assessed using Wiener-kernel (system identification) analyses of single AN fiber responses to broadband noise, for direct comparison to previously published AN responses from animals with NIHL. Wiener-kernel analyses show that even mild NIHL causes grossly abnormal coding of low-frequency stimulus components. In contrast, for MHL the same abnormal coding was only observed with moderate to severe loss. For equal sensitivity loss, coding impairment was substantially less severe with MHL than with NIHL, probably due to greater preservation of the tip-to-tail ratio of cochlear frequency tuning with MHL compared with NIHL rather than different intrinsic AN properties. Differences in peripheral neural coding between these two pathologies-the more severe of which, NIHL, is preventable-likely contribute to individual speech perception differences. Our results underscore the need to minimize noise overexposure and for strategies to personalize diagnosis and treatment for individuals with sensorineural hearing loss.SIGNIFICANCE STATEMENT Differences in speech perception ability between individuals with similar clinically defined severity of hearing loss are often assumed to reflect central neural-processing differences. Here, we demonstrate for the first time that peripheral neural processing of complex sounds differs dramatically between the two most common etiologies of hearing loss. Greater processing impairment with noise-induced compared with an age-related (metabolic) hearing loss etiology may explain heightened speech perception difficulties in people overexposed to loud environments. These results highlight the need for public policies to prevent noise-induced hearing loss, an entirely avoidable hearing loss etiology, and for personalized strategies to diagnose and treat sensorineural hearing loss.

[Maximum monosyllabic score as a predictor for cochlear implant outcome]

OBJECTIVE

This study investigated the speech perception of cochlear implant (CI) recipients with measurable preoperative ipsilateral speech perception. These data should support improved individual counselling of CI candidates.

MATERIALS AND METHODS

Pre- and postoperative speech audiometric parameters were analyzed, including maximum score for phonemically balanced words (PB_max) and monosyllabic score at a normal conversational level of 65 dB_SPL, with hearing aids one hand and CI on the other. Data of 284 experienced adult CI wearers were grouped and evaluated in terms of preoperative PB_max.

RESULTS

The preoperative PB_max was exceeded by the postoperative monosyllabic score in 96% of cases. The overall median postoperative score was 72.5%. The groups with preoperative PB_max > 0% showed significantly better speech perception scores with CI than the group with PB_max = 0 %. Median improvement compared to the preoperative monosyllabic score with hearing aids was 65 percentage points, independent of preoperative PB_max.

CONCLUSION

The preoperatively measured PB_max may be used as a predictor for the minimum speech perception obtained with CI. This is of high clinical relevance for CI candidates with a PB_max above zero.

Maximum preimplantation monosyllabic score as predictor of cochlear implant outcome

Objective

This study investigated the speech perception of cochlear implant (CI) recipients with measurable preoperative ipsilateral speech perception. These data should support improved individual counselling of CI candidates.

Materials and methods

Pre- and postoperative speech audiometric parameters were analyzed, including maximum score for phonemically balanced words (PB_max) and monosyllabic score at a normal conversational level of 65 dB_SPL, with hearing aids one hand and CI on the other. Data of 284 experienced adult CI wearers were grouped and evaluated in terms of preoperative PB_max.

Results

The preoperative PB_max was exceeded by the postoperative monosyllabic score in 96% of cases. The overall median postoperative score was 72.5%. The groups with preoperative PB_max > 0% showed significantly better speech perception scores with CI than the group with PB_max = 0%. Median improvement compared to the preoperative monosyllabic score with hearing aids was 65 percentage points, independent of preoperative PB_max.

Conclusion

The preoperatively measured PB_max may be used as a predictor for the minimum speech perception obtained with CI. This is of high clinical relevance for CI candidates with a PB_max above zero.

Predicting cochlear dead regions in patients with hearing loss through a machine learning-based approach: A preliminary study

We propose a machine learning (ML)-based model for predicting cochlear dead regions (DRs) in patients with hearing loss of various etiologies. Five hundred and fifty-five ears from 380 patients (3,770 test samples) diagnosed with sensorineural hearing loss (SNHL) were analyzed. A threshold-equalizing noise (TEN) test was applied to detect the presence of DRs. Data were collected on sex, age, side of the affected ear, hearing loss etiology, word recognition scores (WRS), and pure-tone thresholds at each frequency. According to the cause of hearing loss as diagnosed by the physician, we categorized the patients into six groups: 1) SNHL with unknown etiology; 2) sudden sensorineural hearing loss (SSNHL); 3) vestibular schwannoma (VS); 4) Meniere's disease (MD); 5) noise-induced hearing loss (NIHL); or 6) presbycusis or age-related hearing loss (ARHL). To develop a predictive model, we performed recursive partitioning and regression for classification, logistic regression, and random forest. The overall prevalence of one or more DRs in test ears was 20.36% (113 ears). Among the 3,770 test samples, the overall frequency-specific prevalence of DR was 6.7%. WRS, pure-tone thresholds at each frequency, disease type (VS or MD), and frequency information were useful for predicting DRs. Sex and age were not associated with detecting DRs. Based on these results, we suggest possible predictive factors for determining the presence of DRs. To improve the predictive power of the model, a more flexible model or more clinical features, such as the duration of hearing loss or risk factors for developing DRs, may be needed.

Can an average of thresholds at 2 kHz and 4 kHz substitute for the threshold at 3 kHz in pure tone audiometry? A study based on the Korean National Health and Nutrition Examination Survey 2010-2012

Background

When evaluating hearing disability in medicolegal cases, an average of thresholds at several frequencies is calculated using pure tone audiometry. Occasionally, there are instances in which thresholds at certain frequencies are omitted. One typical example is the threshold at 3 kHz (H3k). The American Academy of Otolaryngology–Head and Neck Surgery Committee on Hearing and Equilibrium (1995) suggested that the average of thresholds at 2 kHz and 4 kHz (H24k) could replace H3k for a comparison of results between studies. However, to the best of our knowledge, there is no report in the literature that compares H3k and H24k.

Objective

This study aimed to investigate the agreement between H3k and H24k.

Methods

This study is based on the Korea National Health and Nutrition Examination Survey (KNHANES) 2010–2012, which was conducted by the Korean government. A total of 18,472 participants (unweighted) who represented 39,357,497 Koreans (weighted) were included. To verify the agreement of H3k and H24k, a paired t-test, Cohen’s d, Pearson’s correlation, Cronbach’s coefficient, intraclass correlation coefficient (ICC), a Bland–Altman plot, and linear regression analysis were used.

Results

The means of H3k and H24k were 16.2 dBHL and 16.6 dBHL, respectively. They were significantly different in a paired t-test (p<0.0001), which resulted from the large sample size. In contrast, the effect size (Cohen’s d) was 0.02, which meant that the two groups nearly overlapped. The means showed strong correlation: Pearson’s correlation coefficient = 0.92, Cronbach’s alpha = 0.96, and ICC = 0.92. A strong linear predictive relationship between H3k and H24k was found: y = –0.6821 + 1.0186x, where x = H24k, y = H3k, and p<0.0001. However, the Bland–Altman plot showed large upper and lower limits of agreement (LOA) of 15.0 dBHL and –15.8 dBHL, respectively. Irrespective of age and degree of the four-tone average (0.5, 1, 2, and 3 kHz) hearing loss or thresholds at 2 kHz, 3 kHz, and 4 kHz, the absolute LOAs were greater than 10 dBHL.

Conclusions

Despite a very strong correlation between the two thresholds, H3k and H24k showed clinically large LOAs. Therefore, it would be improper to substitute H24k for H3k in an individual requesting a hearing disability rating. However, since the overall means of the H3k and H24k samples were nearly equal, H24k can replace H3k for a mean comparison of results between studies. This result supports the 1995 Committee on Hearing and Equilibrium guideline.

Improvement in Patient-reported Hearing After Treatment With Bevacizumab in People With Neurofibromatosis Type 2

OBJECTIVE

Assess patient-reported outcomes (PRO) for hearing and tinnitus relative to clinical hearing assessment in people with neurofibromatosis 2 (NF2) associated hearing loss.

STUDY DESIGN

Prospective, open label, phase-II clinical trial with PRO administered pre-, post-, and after treatment.

SETTING

Three tertiary referral centers.

PATIENTS

Fourteen patients with NF2, median age of 30 years (range, 14-79 yr) and progressive hearing loss (median baseline word recognition score, 60%; range, 13-82%). Half of these patients achieved objective hearing response (word recognition score improved beyond the 95% critical difference versus baseline).

INTERVENTION

Bevacizumab 7.5 mg/kg was administered every 3 weeks for 48 weeks, followed by surveillance for 24 weeks off-drug.

MAIN OUTCOME MEASURES

Speech, spatial, and qualities of hearing scale (SSQ) and tinnitus reaction questionnaire (TRQ) to assess hearing difficulties in life situations and tinnitus related distress.

RESULTS

Patient-reported speech understanding and auditory quality improved with bevacizumab treatment and were significantly correlated with word recognition scores, but not pure tone threshold average. There was no change in spatial perception after treatment. Reduction in tinnitus distress after treatment with bevacizumab did not reach statistical significance.

CONCLUSION

Participants had reductions in hearing difficulty during treatment with bevacizumab, suggesting that patients subjectively experience hearing-related benefit mirroring clinical hearing assessments. We suspect the lack of significant reduction in tinnitus distress is related to small sample size and low intensity of distress in our sample. These data highlight the usefulness of PRO measures to assess benefits of treatment in the setting of NF2-associated hearing loss.

[Speech audiometry for indication of conventional and implantable hearing aids]

The social function of the human hearing apparatus is comprehension of speech. Auditory rehabilitation aims to enhance speech perception in everyday life. Consequently, audiological evaluation contains speech perception measurement. Many speech audiometric methods have been developed in German-speaking countries, which are suitable for quantification of speech perception abilities in quiet and in noise to address specific diagnostic questions. For establishment of the indication for technical hearing systems such as hearing aids and cochlear implants, the Freiburg monosyllabic test has been employed successfully for many years. Particularly sentence tests have been suggested as a complementary measure for hearing aid indication and assessment. This paper describes the characteristics and range of application of various speech audiometric methods, and highlights the methodological limitations of the individual tests.

Evaluating speech perception of the MAXUM middle ear implant versus speech perception under inserts

OBJECTIVES/HYPOTHESIS

To evaluate the speech perception of the Ototronix MAXUM middle ear implant relative to the cochlear potential for speech perception of patients.

STUDY DESIGN

Clinical study chart review.

METHODS

We performed an evaluation of data from a prospective clinical study of 10 MAXUM patients. Primary outcome measures included comparison of word recognition (WR) scores with MAXUM (WR_MAXUM ) versus word recognition under inserts (WR_inserts ), and the functional gain improvement for pure-tone average (PTA) (0.5, 1, and 2 kHz) and high-frequency pure-tone average (2, 3, and 4 kHz).

RESULTS

Ten ears in 10 adult patients (six female; average age 68.7 years) were included. The average speech perception gap (difference between WR_inserts and WR_MAXUM ) with MAXUM was -9.2% (range, -26% to 4%). A negative number indicates that WR_MAXUM was higher than the WR_inserts . The average PTA with MAXUM was 23.1 dB (range, 18.7-30 dB), a 38.0-dB gain over the preoperative unaided condition (range, 20-53.3 dB). The average high-frequency pure-tone average with MAXUM was 34.4 dB (range, 26-43.3 dB), a 42.8-dB gain over the preoperative unaided condition (range, 32.3-58.7 dB).

CONCLUSIONS

These data demonstrate that a significant, very strong correlation was observed between WR_inserts and WR_MAXUM scores (r = 0.86, P = .001), and a patient's WR_inserts score may be used to reasonably predict the word recognition outcomes with MAXUM.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:456-460, 2018.

[The age effect in evaluation of hearing aid benefits by speech audiometry]

BACKGROUND AND AIM

Hearing loss is one of the most common disabilities in the elderly. The aim of this study was to investigate the relationship between pure-tone hearing loss and maximum monosyllabic perception and speech perception with hearing aids. The focus of the investigation was elderly patients.

MATERIALS AND METHODS

In this prospective study, 188 patients with sensorineural hearing loss were included. The pure-tone audiogram (4FPTA), the Freiburg speech intelligibility test with headphones and the word recognition score with hearing aids at 65 dB SPL were measured and evaluated.

RESULTS

An increasing age was associated with higher discrepancy between the maximum speech perception and speech understanding with hearing aids. The mean difference between maximum monosyllabic perception and speech perception with hearing aids is about 20% in the elderly population.

CONCLUSION

The intended goal of hearing aid prescription, the match between maximum monosyllabic perception and word recognition score with hearing aids within 5 to 10%, is not achieved in the elderly population.

Audiometry-Based Screening Procedure for Cochlear Implant Candidacy

OBJECTIVE

This study defines a screening procedure for cochlear implant (CI) candidacy in hearing aid users by using simple audiometric measures.

METHODS

Within this retrospective study, hearing aid performance and audiometric measures in 185 subjects (318 ears) were analyzed. By means of a linear Naive Bayes classifier, the pure-tone average and the maximum monosyllabic score (PB(max)) were used to predict the aided monosyllabic word score and CI candidacy.

RESULTS

The two parameters PB(max) and four-frequency hearing threshold average can be used to predict speech perception with hearing aids with reasonable accuracy for screening purposes. The classification has a sensitivity of 87% and a specificity of 91%. The classification can be represented by a simple linear formula.

CONCLUSION

CI candidacy can be predicted based on commonly used audiometric measures.Cochlear implant candidacy may be considered if the difference between the average pure-tone threshold (in decibels) and PBmax (in percent) exceeds 8.

Measuring the effects of spectral smearing and enhancement on speech recognition in noise for adults and children

Broadened auditory filters associated with sensorineural hearing loss have clearly been shown to diminish speech recognition in noise for adults, but far less is known about potential effects for children. This study examined speech recognition in noise for adults and children using simulated auditory filters of different widths. Specifically, 5 groups (20 listeners each) of adults or children (5 and 7 yrs), were asked to recognize sentences in speech-shaped noise. Seven-year-olds listened at 0 dB signal-to-noise ratio (SNR) only; 5-yr-olds listened at +3 or 0 dB SNR; and adults listened at 0 or -3 dB SNR. Sentence materials were processed both to smear the speech spectrum (i.e., simulate broadened filters), and to enhance the spectrum (i.e., simulate narrowed filters). Results showed: (1) Spectral smearing diminished recognition for listeners of all ages; (2) spectral enhancement did not improve recognition, and in fact diminished it somewhat; and (3) interactions were observed between smearing and SNR, but only for adults. That interaction made age effects difficult to gauge. Nonetheless, it was concluded that efforts to diagnose the extent of broadening of auditory filters and to develop techniques to correct this condition could benefit patients with hearing loss, especially children.

Audiogram and cochlear implant candidacy--UK perspective

OBJECTIVE AND IMPORTANCE

The candidacy for cochlear implant has changed over time and includes people with lesser degrees of hearing loss. Candidacy is based on the pure-tone audiometry thresholds and aided speech testing. The audiogram does not reflect the actual problems faced by an individual with and without hearing aids. The variability in the actual functional hearing and the pure-tone thresholds makes it difficult for the patients whose audiogram is borderline for cochlear implantation and they are not deriving enough benefit from hearing aids.

CASE PRESENTATION

Retrospective report of the audiological findings of two patients whose cochlear implant funding was refused based on their audiogram. In both instances, they were not deriving benefit from hearing aids and the pure-tone audiometry results were just outside the National Institute for Health and Care Excellence guidelines at 4 kHz.

CONCLUSIONS

Cochlear implant candidacy should be individually based and needs to take into account other factors such as work, quality of life, and social impact rather than just adhering to the pure-tone audiometry guidelines. These guidelines should not be considered as strict criteria nor used to deny the benefit of a cochlear implant at the earliest possible opportunity.

Within-consonant perceptual differences in the hearing impaired ear

The consonant recognition of 17 ears with sensorineural hearing loss is evaluated for 14 consonants /p, t, k, f, s, ∫, b, d, g, v, z, 3, m, n/+/a/, under four speech-weighted noise conditions (0, 6, 12 dB SNR, quiet). One male and one female talker were chosen for each consonant, resulting in 28 total consonant-vowel test tokens. For a given consonant, tokens by different talkers were observed to systematically differ, in both the robustness to noise and/or the resulting confusion groups. Such within-consonant token differences were observed for over 60% of the tested consonants and all HI ears. Only when HI responses are examined on an individual token basis does one find that the error may be limited to a small subset of tokens with confusion groups that are restricted to fewer than three confusions on average. Averaging different tokens of the same consonant can raise the entropy of a listener's responses (i.e., the size of the confusion group), causing the listener to appear to behave in a less systematic way. Quantifying these token differences provides insight into HI perception of speech under noisy conditions and characterizes each listener's hearing impairment.

Temporal bone findings in a case of Susac's syndrome

OBJECTIVE

To describe the histopathologic findings in the temporal bones of a patient with Susac's syndrome (SS).

BACKGROUND

The key clinical features of SS consist of symptoms of encephalopathy, visual defects due to occlusion of branches of the retinal artery, and sensorineural hearing loss. The otopathology in SS has not been described.

MATERIALS AND METHODS

A 51-year-old woman was hospitalized with severe headache, rapidly progressive encephalopathy, and bilateral low-frequency sensorineural hearing loss. Magnetic resonance imaging showed lesions of the corpus callosum. Fluorescein angiography of the eyes showed focal areas of irregular retinal artery caliber and leakage from small vessels. SS was diagnosed. She died of a pulmonary embolus 1 month after onset of symptoms. Both temporal bones were prepared in celloidin and examined using light microscopy.

RESULTS

Findings were nearly identical in both temporal bones. The apical halves of both cochleae showed widespread atrophy of structures of the cochlear duct (inner and outer hair cells, tectorial membranes, striae vasculares, spiral ligaments, and spiral limbi). The apical parts of both cochleae also showed apparent occlusion of capillaries within the stria vascularis and related areas of the cochlear duct. Cochlear neurons were present in normal numbers. There was no endolymphatic hydrops. The vestibular sense organs were normal for age.

CONCLUSION

This first reported otopathologic case of SS with hearing loss showed atrophy and degeneration involving the apical halves of the cochlear duct without inflammation or infection. The findings were consistent with capillary occlusion as being responsible for the atrophy.

Improvement in word recognition score with level is associated with hearing aid ownership among patients with hearing loss

Market surveys consistently show that only 22% of those with hearing loss own hearing aids. This is often ascribed to cosmetics, but is it possible that patients apply a different auditory criterion than do audiologists and manufacturers? We tabulated hearing aid ownership in a survey of 1000 consecutive patients. We separated hearing loss cases, with one cohort in which word recognition in quiet could improve with gain (vs. 40 dB HL) and another without such improvement but nonetheless with audiometric thresholds within the manufacturer's fitting ranges. Overall, we found that exactly 22% of hearing loss patients in this sample owned hearing aids; the same finding has been reported in many previous, well-accepted surveys. However, while all patients in the two cohorts experienced difficulty in noise, patients in the cohort without word recognition improvement were found to own hearing aids at a rate of 0.3%, while those patients whose word recognition could increase with level were found to own hearing aids at a rate of 50%. Results also coherently fit a logistic model where shift of the word recognition performance curve by level corresponded to the likelihood of ownership. In addition to the common attribution of low hearing aid usage to patient denial, cosmetic issues, price, or social stigma, these results provide one alternative explanation based on measurable improvement in word recognition performance.

Proteome of human perilymph

Current diagnostic tools limit a clinician's ability to discriminate between many possible causes of sensorineural hearing loss. This constraint leads to the frequent diagnosis of the idiopathic condition, leaving patients without a clear prognosis and only general treatment options. As a first step toward developing new diagnostic tools and improving patient care, we report the first use of liquid chromatography-tandem mass-spectrometry (LC-MS/MS) to map the proteome of human perilymph. Using LC-MS/MS, we analyzed four samples, two collected from patients with vestibular schwannoma (VS) and two from patients undergoing cochlear implantation (CI). For each cohort, one sample contained pooled specimens collected from five patients and the second contained a specimen obtained from a single patient. Of the 271 proteins identified with high confidence among the samples, 71 proteins were common in every sample and used to conservatively define the proteome of human perilymph. Comparison to human cerebrospinal fluid and blood plasma, as well as murine perilymph, showed significant similarity in protein content across fluids; however, a quantitative comparison was not possible. Fifteen candidate biomarkers of VS were identified by comparing VS and CI samples. This list will be used in future investigations targeted at discriminating between VS tumors associated with good versus poor hearing.

Hearing aids and cochlear damage: the case against fitting the pure tone audiogram

Herein we propose a different approach to hearing aids, an approach that flows logically from the pathophysiology of cochlear disorders. This approach challenges some central tenets of the industry by 1) suggesting that many, if not most, cases would be better served by flat, undistorted gain across all frequencies rather than by "fitting" gain to the audiogram; and 2) suggesting that most of the improvements in hearing aid technology are targeted at reducing patient complaints as opposed to increasing measurable word recognition performance. We recommend that it is better to accommodate the damaged cochlea in these cases than to attempt to reverse-engineer the audiometric test results.