Florian Herrmann Schmidt

Objective: To apply a semiautomatic method for quantifying cochlear nerve cross-sectional area (CSA) based on 3D models from MRI picture and to evaluate the association between CSA at different nerve locations and postoperative speech perception in cochlear implant (CI) users. Study design: Retrospective cohort study. Setting: University Medical Center, tertiary academic referral center. Patients: Twenty adult patients with asymmetric hearing loss undergoing a MED-EL cochlear implant (Synchrony 2, FLEX electrode series; MED-EL, Innsbruck, Austria) between 2020 and 2024. Intervention: Preoperative MRI images were used for manual segmentation for the cochlear nerve (CN) and facial nerve (FN) followed by 3D reconstruction. CSA of the CN (ACN) and FN (AFN) was automatically quantified along the entire nerve course. Postoperative speech perception was assessed using word recognition scores (WRS) at the first fitting. Main outcome measures: Semiautomatic CSA measurements showed excellent agreement with manual measurements (R _ANC =0.95±0.06). CSA near the cochlear aperture exhibited the strongest correlation with postoperative speech perception. Peak correlation for polysyllabic tests at approximately 10% of the normalized nerve length (R _max =0.74) and for monosyllabic tests at approximately 24% (R _max =0.56). Conclusion: This study establishes a reliable semiautomatic method for cochlear nerve CSA quantification and identifies the nerve region near the cochlear aperture as a promising imaging biomarker for predicting postoperative speech outcomes in CI patients

Background/Objectives: In the early stage of presbycusis, patients experience reduced speech perception in noisy environments despite normal audiometry, normally known as hidden hearing loss. Diagnostic indicators like the reduced amplitude of ABR wave I, elevated extended high-frequency threshold (EHT), and decreased middle ear muscle reflex (MEMR) amplitude aim to identify biomarkers of peripheral auditory pathology but remain inconsistent. Mismatch negativity (MMN) is a cortical auditory evoked potential generated when the brain detects sound changes. This study aimed to assess MMN as a diagnostic tool for hidden hearing loss in adults. Methods: Seventy-three subjects with normal hearing underwent an extended pure-tone audiogram examination ranging from 0.125 to 16 kHz and a subsequent MMN assessment with two different paradigms: a speech (ba/da) and a tone (1/2 kHz) paradigm. The MMN’s amplitude and latency were measured and analyzed. Results: The outcome shows a significant age-related effect on MMN amplitude in the speech condition (χ² = 13.0, p = 0.002). Specifically, the MMN amplitude in the 25–30-year-old group was significantly smaller than in the 20–25-year-old group (p = 0.0015, Cohen’s d = 0.63). Additionally, no further effects of age were observed on the cortical potentials examined. Also, neither tone nor speech paradigms showed a significant influence of EHT on the amplitude or latency of either MMN or P300. Conclusions: The application of MMN as an electrophysiological tool to diagnose hidden hearing loss in normal hearing adults has limitations. However, in contrast to MMN responses to tonal stimuli, the present study reveals that MMN amplitude obtained with speech stimuli may indicate early signs of central auditory deficits.

Purpose Patients with age-related hearing loss complain often about reduced speech perception in adverse listening environment. Studies on animals have suggested that cochlear synaptopathy may be one of the primary mechanisms responsible for this phenomenon. A decreased wave I amplitude in supra-threshold auditory brainstem response (ABR) can diagnose this pathology non-invasively. However, the interpretation of the wave I amplitude in humans remains controversial. Recent studies in mice have established a robust and reliable mathematic algorithm, i.e., curve curvature quantification, for detecting cochlear synaptopathy. This study aimed to determine whether the curve curvature has sufficient test–retest reliability to detect cochlear synaptopathy in aging humans. Methods Healthy participants were recruited into this prospective study. All subjects underwent an audiogram examination with standard and extended high frequencies ranging from 0.125 to 16 kHz and an ABR with a stimulus of 80 dB nHL click. The peak amplitude, peak latency, curvature at the peak, and the area under the curve of wave I were calculated and analyzed. Results A total of 80 individuals with normal hearing, aged 18 to 61 years, participated in this study, with a mean age of 26.4 years. Pearson correlation analysis showed a significant negative correlation between curvature and age, as well as between curvature and extended high frequency (EHF) threshold (10–16 kHz). Additionally, the same correlation was observed between age and area as well as age and EHF threshold. The model comparison demonstrated that the curvature at the peak of wave I is the best metric to correlate with EHF threshold. Conclusion The curvature at the peak of wave I is the most sensitive metric for detecting cochlear synaptopathy in humans and may be applied in routine diagnostics to detect early degenerations of the auditory nerve.

Among hearing aid (HA) users, there is a considerable variability in word recognition scores (WRSs). This variability is most pronounced among individuals with moderately severe to severe hearing loss. The variability cannot be adequately explained by factors such as pure-tone audiogram, audiogram type or age. This prospective study was designed to investigate the relationship between tone decay (TD) and WRS in a group of HA users with corresponding pure-tone hearing loss. The study population included 22 patients with hearing loss between 50 and 80 dB HL. Aided WRS, unaided WRS and TD were assessed for both ears. TD was found to be frequency-dependent. TD and WRS were correlated, with up to R = −0.66. The TD test was revealed to be a feasible method for explaining variability in WRS among HA users with hearing loss below 80 dB. This may contribute to improved differential diagnostics. The TD test may thus offer a better understanding of the limitations of HA use in the context of cochlear implant candidacy assessment for HA users.

Among hearing aid (HA) users, there is a considerable variability in word-recognition scores (WRS). This variability is most pronounced among individuals with moderately severe to severe hearing loss. The variability cannot be adequately explained by factors such as the pure-tone audiogram, audiogram type, or age. This prospective study was designed to investigate the relationship between tone decay (TD) and WRS in a group of HA users with corresponding pure-tone hearing loss. The study population included 22 patients with hearing loss between 50 and 80 dB HL. Aided WRS, unaided WRS and TD were assessed for both ears. TD was found to be frequency-dependent. TD and WRS were correlated, with up to R=–0.66. The TD test was revealed as a feasible method for explaining the variability in WRS among HA users with hearing loss below 80 dB. This may contribute to improved differential diagnostics. The TD test may thus offer a better understanding of the limitations of HA use in the context of cochlear implant candidacy assessment for HA users.