Book Review: Rapid Audiogram Interpretation: A Clinician's Manual by Squires LD, Colombo BA, McKinney S. Plural Publishing, San Diego, 2019. No abstract available

Steroid Nomenclature in Inner Ear Therapy Local glucocorticosteroid (“steroid”) therapy is widely used to treat the inner ears of patients with Menière's disease, idiopathic sudden sensorineural hearing loss and in combination with cochlear implants. Applied steroids have included dexamethasone, methylprednisolone, and triamcinolone. In reality, however, this is often not true and the steroid forms commonly applied are dexamethasone-phosphate, methylprednisolone-hemisuccinate, or triamcinolone-acetonide. In each case, the additional component is not a counter-ion but is covalently bound to the molecule to increase aqueous solubility or potency. These drug forms are approved for intravenous or intramuscular delivery and are used “off-label” in the ear. When given systemically, the molecular form of the drug is of minor importance as the drugs are rapidly metabolized. In contrast, when administered intratympanically, the exact form of the drug has a major influence on entry into perilymph and elimination from perilymph, which in turn influences distribution along the cochlear scalae. Dexamethasone-phosphate has completely different molecular properties to dexamethasone and has different pharmacokinetic properties entering and leaving perilymph. Molecular properties and perilymph pharmacokinetics also differ markedly for triamcinolone and triamcinolone-acetonide. Methylprednisolone-hemisuccinate has completely different molecular properties to methylprednisolone. In the ear, different steroid forms cannot therefore be regarded as equivalent in terms of pharmacokinetics or efficacy. This presents a terminology problem, where in many cases the drug stated in publications may not be the form actually administered. The lack of precision in nomenclature is a serious problem for the inner ear drug delivery field and needs to be recognized.

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.

Single-Sided Deafness—Outcomes of Three Interventions for Profound Unilateral Sensorineural Hearing Loss: A Randomized Clinical Trial Objective: A comparison of three interventions for profound unilateral sensorineural hearing loss. Study Design: Prospective, crossover randomized clinical trial. Participants: Fifteen participants with profound unilateral sensorineural hearing loss. Interventions: Three potential technical interventions were compared: Bone Conduction Device on softband, Contralateral Routing of Signal (CROS), and Remote Microphone . Each intervention was randomly trialed for a period of 3 weeks, separated by a 1 week washout period. Outcome Measures: Speech in noise recognition test performed under four conditions (lateral noise poorer ear, lateral noise better ear, speech poorer ear, speech better ear). Standardized questionnaires (Abbreviated Profile of Hearing Aid Benefit, Bern Benefit in Single Sided Deafness Questionnaire, and Speech, Spatial, and Other Qualities 12) were used to evaluate amplification benefit at baseline and following each intervention. Results: The use of remote microphone provided the best results in the speech recognition in noise test. A benefit in some signal-to-noise ratios was presented of the CROS over bone conduction device on softband in the Speech Poor Ear condition. On questionnaires of benefit, participants did not rate a particular intervention as significantly better than any other. Following the study, CROS was the intervention preferred by the 8 of 15 participants (53%). The majority of participants (80%) chose to continue with an intervention rather than no treatment. Conclusion: The use of all interventions resulted in increased performance in speech recognition in noise and rated higher on subjective benefits in comparison with baseline. People with SSD are a heterogeneous population when considering perceived difficulties. Future research should focus on segmenting the population of SSD depending on factors such as etiology, high frequency loss in the better ear, and age of acquired loss for the poorer ear. This stratification may possibly increase the benefit for the patient in terms of more individual-based clinical routines.

Subjective Hearing Impression and Quality of Life in Patients With Bilateral Active Middle Ear Implants Objective: This study compared the quality of life in patients with bilateral active middle ear implants to their quality of life when they were unilaterally implanted. Design: Twenty-one patients implanted sequentially with the Vibrant Soundbridge (VSB) active middle ear implant completed quality-of-life surveys. The patients were asked to rate whether and to what extent their quality of life has changed upon receiving a second VSB. Hearing-specific quality of life was assessed with the Speech, Spatial, and Qualities of Hearing Scale (SSQ12-B), and general quality of life was with the Glasgow Benefit Inventory (GBI). In addition, the patients completed a health-related quality-of-life questionnaire (AQoL-8D). Finally, the changes in hearing-related and general quality of life were correlated to the change in word recognition ability after implantation of the second VSB (Freiburg monosyllabic word test; unilateral VSB versus bilateral VSB at 65 dB SPL). Results: On the SSQ12, subjects scored a median of + 2.73 (p < 0.001; significantly different from zero) on a scale of −5 to + 5 where 0 indicates no change. All three subscores showed significant improvement. On the GBI, patients reached a median overall score of + 23.6 (p < 0.001; significantly different from zero) on a scale of −100 to + 100 where 0 indicates no change. Here, the improvement was mainly visible in the general subscore, whereas the social support and physical health subscores did not change due to the intervention. Both subjective benefit rating scores strongly correlated with the change in word recognition scores, suggesting that both hearing and general quality of life improved with increased word recognition due to bilateral VSB use. No significant correlation was found between the subjects’ general health (as measured by AQoL-8D utility scores) and SSQ12-B or GBI overall scores. Conclusion: Usage of a second active middle ear implant substantially improved our patients’ subjective hearing and general quality of life compared with unilateral use. The increase in quality of life may be linked to improved speech understanding due to bilateral use of a middle ear implant. Furthermore, these outcomes were not influenced by our patients’ general health state at the time of survey.

Otoprotective Effects of α-lipoic Acid on A/J Mice With Age-related Hearing Loss Objective: A/J mice are a mouse model of age-related hearing loss (AHL) with progressive degeneration of outer hair cells (OHCs), spiral ganglion neurons (SGNs), and stria vascularis. This study was carried out to observe the otoprotective effects of α-lipoic acid on A/J mice. Methods: A/J mouse pups at postnatal day 7 were randomly distributed into the untreated group, the dimethyl sulfoxide (DMSO) group, and the α-lipoic acid + DMSO group. α-lipoic acid was given to the mice intraperitoneally at a dosage of 50 μg/g body weight every other day. Time course auditory-evoked brainstem response (ABR) thresholds were tested. OHC loss was counted and the densities of SGNs and the width of stria vascularis were measured at 4 and 8 weeks of age. Results: Measurement of the ABR thresholds revealed that hearing loss in A/J mice was attenuated by α-lipoic acid at age from 3 to 8 weeks. Moreover, preservation effects of OHCs, SGNs, and stria vascularis by α-lipoic acid were observed in the cochleae of A/J mice at 4 and 8 weeks of age. Conclusion: Hearing loss in A/J mice can be attenuated by α-lipoic acid. The otoprotective effects of α-lipoic acid on A/J mice may be obtained by preserving OHCs, SGNs, and stria vascularis in the cochleae. The oxidative damage related to gene mutations may be a potential target for AHL prevention and therapy.

Subjective Loudness Using External Noise Reflects the Loudness and Distress of Tinnitus: A Cross-Sectional Study Objectives: Subjective tinnitus loudness has been measured using loudness matches, which compare tinnitus loudness with pure tones from an audiometer. When patients compare the sound pressure of certain noises with the tinnitus loudness, however, there may be remarkable differences from the measurements according to loudness matches. Subjective loudness (SubL) is an estimation of the sound pressure of tinnitus loudness by comparison of noises considered to be most similar to tinnitus loudness of patient. We examine whether SubL is inferior to loudness matches in measurement of subjective tinnitus loudness. Design: Single-group cross-sectional study. Patients: Included in this study were a clinical group of 111 patients with the chief complaint of subjective tinnitus. Seven of the 111 patients were excluded due to missing audiometry or questionnaire data. Methods: Patients assessed the tinnitus loudness and related distress using visual analogue scales (VAS-L and VAS-S) and answered the Tinnitus Handicap Inventory (THI). Hearing acuity, tinnitus pitch, and loudness were then measured using an audiometer. Results: VAS-L, VAS-S, and THI scores significantly correlated with loudness match using Goodwin's method (SL2) and SubL. Subgroup analysis based on patient ages indicated that all correlations of SL2 with VAS-L, VAS-S, and THI scores were no longer seen in patients more than 60 years of age. Meanwhile, SubL correlated with VAS-L, VAS-S, and THI scores in all subgroups. Conclusions: SubL was a good reflection of self-reported loudness and distress of tinnitus. It may therefore be a simple and easy means of assessing tinnitus loudness and associated distress during pre-examination without an audiometer.

The Cochlear Cleft: CT Correlation With Histopathology Objective: To show the histologic correlate of the cochlear cleft, a small low density focus just anterior to the oval window seen on computed tomography (CT) in three temporal bone specimens. Patients: Three temporal bone specimens donated to the National Temporal Bone Registry from patients aged 34 weeks gestation, 42 years, and 89 years with cochlear clefts seen on CT were studied. Intervention: Review and comparison of postmortem high-resolution CT and temporal bone histopathology Main Outcome Measure: Correlation of CT findings with temporal bone histopathology. Results: The cochlear cleft visible on CT as a pericochlear lucency anterior to the oval window corresponds to fatty marrow in areas of incomplete endochondral ossification of the otic capsule. The cochlear cleft is distinct from the fissula ante fenestram and can be present in adults. Conclusion: In these three cases, the cochlear cleft represents an area of fatty marrow from incomplete ossification of the otic capsule and can be present in adults. Care should be taken when interpreting temporal bone CT to avoid mistaking the cochlear cleft for true pathology (otosclerosis) of the temporal bone.

Clinical Profiles of DFNA11 at Diverse Stages of Development and Aging in a Large Family Identified by Linkage Analysis Hypothesis: The phenotype of DFNA11 consists of specific features at diverse developmental and age stages. Background: Only eight mutations have been identified for autosomal dominant non-syndromic hearing loss related to MYO7A (DFNA11), and the onset and progression of DFNA11 are poorly understood. Methods: After linkage analysis and following Sanger sequencing in a family suspected to have autosomal dominant hereditary hearing loss, we analyzed the audiometric and vestibular functions and their long-term changes in the subjects carrying the variant. Results: A reported variant of uncertain significance, NP_000251.3:p.Arg853His, in MYO7A was detected and cosegregation data of this large family provided evidence that the variant was likely pathogenic for DFNA11. Family members with the variant had no other symptoms associated with hearing loss and were confirmed to have autosomal dominant non-syndromic sensorineural hearing loss. Audiograms tended to show gently sloping configuration in childhood and flat configuration after the age of 30 years. Hearing loss at high frequencies progressed slowly, while hearing at low frequencies started to deteriorate later but progressed more rapidly. Some subjects showed partly abnormal results in the distortion products of otoacoustic emissions before the elevation of hearing thresholds. Vestibular function was within the normal range in all the subjects tested. Conclusion: We revealed that hearing loss at high frequencies was mainly noted in early developmental stages and that thresholds increased more rapidly in the low frequency range, resulting in changes in audiometric configuration. Deterioration of distortion product otoacoustic emissions (DPOAE) before the elevation of hearing thresholds was considered as a clinical feature of DFNA11.

Long-term Hearing Preservation in Electric Acoustic Cochlear Implant Candidates Objectives: To evaluate long-term stability and residual hearing preservation after cochlear implantation with electric acoustic stimulation (EAS). Study Design: Retrospective chart-analysis. Setting: University clinic. Methods: Long- and short-term hearing preservation (HP) of 18 EAS subjects (21 ears) was evaluated. Short-term was defined as follow-ups less than 12 months after surgery versus long-term outcomes longer than 12 months postsurgery. Results: Mean period of observation in the short-term group was 4 ± 3.0 months (range 0–7). In the long-term group the mean follow-up was 28.4 ± 15.0 months (range 12–58). Full insertion was possible in all 18 implanted subjects. In the short-term group, complete HP was achieved in 50%, partial HP in 33.3%, and minimal HP in 8.3% of the investigated subjects. One subject lost hearing completely. In the long-term group, complete HP was achieved in 50%, partial HP was observed in 40%, and minimal HP in 10% of the ears. No subject lost hearing completely. Subjects using EAS showed better word recognition scores after surgery (mean at 65 dB 55.3 ± 18.4; mean at 80 dB 68.1 ± 12.2) than subjects using electric stimulation only (mean at 65 dB 38.3 ± 18.1; mean at 80 dB 60.0 ± 16.4) with nonfunctional low-frequency hearing. Conclusion: The study confirms that hearing can be preserved to a large extent. As a result, most subjects benefitted from EAS. Subjects with postoperative functional low-frequency hearing showed greater benefit in word speech tests. Furthermore, the outcomes show that EAS implantation is a safe, effective, and most importantly stable treatment option (longest follow-up with 58 mo).