Cornelis P. Lanting

Objective: This study aims to analyze the progression of hearing loss using prospectively collected data and describe the vestibular phenotype of Usher syndrome type 2A (USH 2a ). Study Design: Longitudinal, prospective, observational natural history study. Patients: Patients with USH2a and USH2A -associated non-syndromic retinitis pigmentosa (nsRP). Main Outcome Measures: Hearing loss progression was measured by pure tone audiometry (PTA) and phoneme scores. Vestibular function was assessed by velocity step tests (VSTs), video head impulse tests (vHITs), caloric reflex tests, and vestibular evoked myogenic potentials (VEMPs). Patient-reported symptoms were assessed by questionnaires (Usher Lifestyle Survey, SF-12, PHQ-9, DHI, and SSQ). Results: Thirty-three patients with USH2a and 2 patients with nsRP were included. PTA _0.5-4kHz thresholds showed a significant decrease of 2.3 dB ( P =0.017) over 4 years. The progression of hearing loss was most pronounced in the mid-to-high frequencies. No significant differences were observed in phoneme scores as measured by the Speech Reception Threshold (SRT). The 2 patients with nsRP had normal hearing. Vestibular evaluation showed abnormal cervical VEMPs in 34% and abnormal ocular VEMPs in 75% of USH2a patients. VSTs, caloric reflex tests, and vHIT results were within normal limits in more than 90% of subjects. Patient questionnaires revealed no major balance problems as indicated by the DHI. Conclusions: This analysis provides robust evidence of measurable hearing loss progression in PTA _0.5-4kHz thresholds in USH2a patients beyond presbycusis. Speech understanding, as measured by SRT, remains relatively stable. Vestibular evaluation revealed no semicircular canal dysfunction, although VEMP results suggest a potential subclinical otolith organ impairment in USH2a patients.

Objective: The objective of this study was to assess the safety and tolerability of the intratympanic delivery of AC102, a novel pharmaceutical therapy based on a thermosensitive gel for preventing and treating a range of hearing impairments, including sudden sensorineural hearing loss. We studied this in healthy, normal-hearing volunteers to evaluate any change in hearing thresholds. Study Design: An open-label, placebo-controlled, ascending single-dose, multicenter phase 1 clinical trial. Setting: The study was conducted in two centers (blinded for reviewing purposes). Subjects: Forty-two normal-hearing healthy volunteers younger than 40 years of age were eligible for enrollment in the study. Intervention: A single intratympanic injection of a thermosensitive gel, either a placebo or containing AC102, to the middle ear. Main Outcome Measure: The primary objective of this study was to assess the safety and tolerability of a single intratympanic injection of ascending volume of placebo and ascending volume and concentration of AC102. The secondary objective was to determine single-dose pharmacokinetics of intratympanically injected AC102 and to evaluate any change in hearing thresholds in healthy male and female subjects. Results: The intratympanic delivery of AC102 thermogel was safe and well tolerated in healthy volunteers with normal hearing, with no permanent adverse events recorded. A mild and temporary volume-dependent conductive hearing loss in the higher frequencies was observed irrespective of AC102 or placebo, which did not result in long-term changes in hearing. Other transient adverse events related to the injection procedure were largely similar between placebo gel and AC102 suspension, consisting mainly of mild ear discomfort, tinnitus, otalgia, and the formation of a droplet of blood at the injection site. Conclusions: The results of this phase 1 clinical trial suggest that the intratympanic delivery of AC102 is a safe and well-tolerated approach for drug delivery to the inner ear in healthy volunteers with normal hearing. As temporary, volume-dependent, conductive hearing losses were observed in the higher frequencies, it is recommended that patients are counseled on a short-term increase in hearing thresholds following injection for conditions such as sudden hearing loss.

Purpose: Cochlear implants (CIs) are an effective rehabilitation option for individuals with severe-to-profound sensorineural hearing loss (SNHL). While genetic factors play a significant role in SNHL, the variability in CI outcomes remains unclear. This study evaluated short- and long-term CI outcomes in a large genotyped cohort and investigated correlations with genetic defects and their cochlear site-of-lesion. Methods: This retrospective, single-center, cohort study included 220 subjects (127 females; 299 ears) with pathogenic variants identified in 31 different nuclear genes and in mitochondrial genes. Audiological outcomes were measured pre- and post-implantation. Cochlear site-of-lesion was categorized as pre-synaptic, post-synaptic, or mitochondrial, based on gene function or expression. Multiple regression analysis assessed factors influencing outcomes, including age at implantation, SNHL duration, hearing aid (HA) use, and cochlear site-of-lesion. Results: Results showed a median phoneme score of 90%, with better outcomes in early implantation (≤ 6 years). Variability in outcomes was not linked to cochlear site-of-lesion, but to subject-specific factors, such as age at implantation, duration of SNHL, pre-implantation HA use, and CI experience. A model incorporating these subject-specific factors explained 19% of the total variance in outcomes. Poorer outcomes (phoneme scores < 70%) were more common in individuals with prolonged auditory deprivation or older age at implantation. Conclusion: Genotyped CI recipients demonstrated excellent outcomes, with variability largely attributed to non-genetic factors. These findings show that cochlear implantation is a beneficial type of rehabilitation for most individuals with hereditary SNHL and underscore the importance of early implantation.

Purpose: This study assessed whether the Fazekas score could account for the variability in cochlear implantation (CI) outcomes among individuals with DFNA9 and evaluated signal loss in the semicircular canals (SCCs) on magnetic resonance imaging (MRI) among individuals with DFNA9. Method: This retrospective cross-sectional study included CI recipients with DFNA9. Pre-implantation MRI-scans were reviewed to determine the Fazekas score, localizing and grading cerebral white matter lesions (WML), and identify abnormalities in the SCCs. CI performance was assessed by evaluating phoneme scores one year post-implantation. The function of the SCCs was evaluated using rotatory chair testing with electronystagmography (ENG) and the video Head Impulse Test (vHIT). Results: Forty-five subjects (49 ears) were enrolled. The phoneme scores significantly improved from 35% (IQR 11–50) pre-implantation to 84% (IQR 76–90) one year post-implantation. No correlation was observed between the Fazekas score and the one-year post-implantation phoneme score (r_sp=0.003, p = 0.986). Signal loss in at least one SCCs was detected in 97.7% of subjects and 77.8% of ears. There was no correlation between vestibular test results and fluid signal loss in the SCCs on MRI. Conclusion: Most individuals with DFNA9 show improved speech recognition with CI. The observed variability in CI outcomes was not linked to the Fazekas score. Additionally, our study confirms a high prevalence of focal sclerosis in DFNA9. Recognizing the limitations of this study, further research is needed to explore the predictive role of the Fazekas score on CI outcomes and its relationship with vestibular function.

Purpose: Cisplatin-induced hearing loss is a common side effect in patients treated with cisplatin-based chemoradiation (CRT) for head and neck squamous cell carcinoma. The extent of hearing loss after concurrent CRT was compared between triweekly (3 × 100 mg/m²) and weekly (7 × 40 mg/m²) cisplatin CRT. Method: This retrospective cohort study was conducted in the Antoni van Leeuwenhoek Hospital and included 129 patients with cisplatin-based CRT for head and neck cancer (72 treated in the triweekly and 57 in the weekly regimen). Baseline and follow-up pure tone audiometry was conducted to assess hearing loss. Clinically relevant hearing loss was defined as a decline upon treatment of ≥ 10 decibel at a pure tone average 1-2-4 kHz and/or 8-10-12.5 kHz. Results: The incidence of clinically relevant cisplatin CRT induced hearing loss was 42% in the triweekly versus 19% in the weekly group (p < 0.01). The mean threshold shift at a pure tone average (PTA) 1-2-4 kHz was 9.0 decibel in the triweekly compared to 4.3 decibel in the weekly CRT group (p < 0.01). At PTA 8-10-12.5 kHz, the incidence of clinically relevant hearing loss was 75% in the triweekly compared to 74% in the weekly CRT group (p = 0.87). The mean threshold shift at PTA 8-10-12.5 kHz was 20.2 decibel versus 15.6 decibel, respectively (p = 0.07). Conclusion: Cisplatin-dose reduction to a weekly cisplatin CRT regimen for head and neck cancer may reduce the incidence of clinically relevant hearing loss at frequencies vital for speech perception.

The aim of this study is to contribute to a better description of the genotypic and phenotypic spectrum of DFNA6/14/38 and aid in counseling future patients identified with this variant. Therefore, we describe the genotype and phenotype in a large Dutch–German family (W21-1472) with autosomal dominant non-syndromic, low-frequency sensorineural hearing loss (LFSNHL). Exome sequencing and targeted analysis of a hearing impairment gene panel were used to genetically screen the proband. Co-segregation of the identified variant with hearing loss was assessed by Sanger sequencing. The phenotypic evaluation consisted of anamnesis, clinical questionnaires, physical examination and examination of audiovestibular function. A novel likely pathogenic WFS1 variant (NM_006005.3:c.2512C>T p.(Pro838Ser)) was identified in the proband and found to co-segregate with LFSNHL, characteristic of DFNA6/14/38, in this family. The self-reported age of onset of hearing loss (HL) ranged from congenital to 50 years of age. In the young subjects, HL was demonstrated in early childhood. At all ages, an LFSNHL (0.25–2 kHz) of about 50–60 decibel hearing level (dB HL) was observed. HL in the higher frequencies showed inter-individual variability. The dizziness handicap inventory (DHI) was completed by eight affected subjects and indicated a moderate handicap in two of them (aged 77 and 70). Vestibular examinations (n = 4) showed abnormalities, particularly in otolith function. In conclusion, we identified a novel WFS1 variant that co-segregates with DFNA6/14/38 in this family. We found indications of mild vestibular dysfunction, although it is uncertain whether this is related to the identified WFS1 variant or is an incidental finding. We would like to emphasize that conventional neonatal hearing screening programs are not sensitive to HL in DFNA6/14/38 patients, because high-frequency hearing thresholds are initially preserved. Therefore, we suggest screening newborns in DFNA6/14/38 families with more frequency-specific methods.

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

Usher syndrome (USH) is an autosomal recessively inherited disease characterized by sensorineural hearing loss (SNHL) and retinitis pigmentosa (RP) with or without vestibular dysfunction. It is highly heterogeneous both clinically and genetically. Recently, variants in the arylsulfatase G (ARSG) gene have been reported to underlie USH type IV. This distinct type of USH is characterized by late-onset RP with predominantly pericentral and macular changes, and late onset SNHL without vestibular dysfunction. In this study, we describe the USH type IV phenotype in three unrelated subjects. We identified three novel pathogenic variants, two novel likely pathogenic variants, and one previously described pathogenic variant inARSG. Functional experiments indicated a loss of sulfatase activity of the mutant proteins. Our findings confirm thatARSGvariants cause the newly defined USH type IV and support the proposed extension of the phenotypic USH classification.

Pathogenic missense variants in COCH are associated with DFNA9, an autosomal dominantly inherited type of progressive sensorineural hearing loss with or without vestibular dysfunction. This study is a comprehensive overview of genotype-phenotype correlations using the PRISMA and HuGENet guidelines. Study characteristics, risk of bias, genotyping and data on the self-reported age of onset, symptoms of vestibular dysfunction, normative test results for vestibular function, and results of audiovestibular examinations were extracted for each underlying pathogenic COCH variant. The literature search yielded 48 studies describing the audiovestibular phenotypes of 27 DFNA9-associated variants in COCH. Subsequently, meta-analysis of audiometric data was performed by constructing age-related typical audiograms and by performing non-linear regression analyses on the age of onset and progression of hearing loss. Significant differences were found between the calculated ages of onset and progression of the audiovestibular phenotypes of subjects with pathogenic variants affecting either the LCCL domain of cochlin or the vWFA2 and Ivd1 domains. We conclude that the audiovestibular phenotypes associated with DFNA9 are highly variable. Variants affecting the LCCL domain of cochlin generally lead to more progression of hearing loss when compared to variants affecting the other domains. This review serves as a reference for prospective natural history studies in anticipation of mutation-specific therapeutic interventions.