Results of a multicentre randomised controlled trial of cochlear-sparing intensity-modulated radiotherapy versus conventional radiotherapy in patients with parotid cancer (COSTAR; CRUK/08/004).

PURPOSE: About 40-60% of patients treated with post-operative radiotherapy for parotid cancer experience ipsilateral sensorineural hearing loss. Intensity-modulated radiotherapy (IMRT) can reduce radiation dose to the cochlea. COSTAR, a phase III trial, investigated the role of cochlear-sparing IMRT (CS-IMRT) in reducing hearing loss. METHODS: Patients (pT1-4 N0-3 M0) were randomly assigned (1:1) to 3-dimensional conformal radiotherapy (3DCRT) or CS-IMRT by minimisation, balancing for centre and radiation dose of 60Gy or 65Gy in 30 daily fractions. The primary end-point was proportion of patients with sensorineural hearing loss in the ipsilateral cochlea of ≥10 dB bone conduction at 4000 Hz 12 months after radiotherapy compared using Fisher's exact test. Secondary end-points included hearing loss at 6 and 24 months, balance assessment, acute and late toxicity, patient-reported quality of life, time to recurrence and survival. RESULTS: From Aug 2008 to Feb 2013, 110 patients (54 3DCRT; 56 CS-IMRT) were enrolled from 22 UK centres. Median doses to the ipsilateral cochlea were 3DCRT: 56.2Gy and CS-IMRT: 35.7Gy (p < 0.0001). 67/110 (61%) patients were evaluable for the primary end-point; main reasons for non-evaluability were non-attendance at follow-up or incomplete audiology assessment. At 12 months, 14/36 (39%) 3DCRT and 11/31 (36%) CS-IMRT patients had ≥10 dB loss (p = 0.81). No statistically significant differences were observed in hearing loss at 6 or 24 months or in other secondary end-points including patient-reported hearing outcomes. CONCLUSION: CS-IMRT reduced the radiation dose below the accepted tolerance of the cochlea, but this did not lead to a reduction in the proportion of patients with clinically relevant hearing loss.

The CAPOS mutation in ATP1A3 alters Na/K-ATPase function and results in auditory neuropathy which has implications for management.

Cerebellar ataxia, areflexia, pes cavus, optic atrophy and sensorineural hearing impairment (CAPOS) is a rare clinically distinct syndrome caused by a single dominant missense mutation, c.2452G>A, p.Glu818Lys, in ATP1A3, encoding the neuron-specific alpha subunit of the Na+/K+-ATPase α3. Allelic mutations cause the neurological diseases rapid dystonia Parkinsonism and alternating hemiplegia of childhood, disorders which do not encompass hearing or visual impairment. We present detailed clinical phenotypic information in 18 genetically confirmed patients from 11 families (10 previously unreported) from Denmark, Sweden, UK and Germany indicating a specific type of hearing impairment-auditory neuropathy (AN). All patients were clinically suspected of CAPOS and had hearing problems. In this retrospective analysis of audiological data, we show for the first time that cochlear outer hair cell activity was preserved as shown by the presence of otoacoustic emissions and cochlear microphonic potentials, but the auditory brainstem responses were grossly abnormal, likely reflecting neural dyssynchrony. Poor speech perception was observed, especially in noise, which was beyond the hearing level obtained in the pure tone audiograms in several of the patients presented here. Molecular modelling and in vitro electrophysiological studies of the specific CAPOS mutation were performed. Heterologous expression studies of α3 with the p.Glu818Lys mutation affects sodium binding to, and release from, the sodium-specific site in the pump, the third ion-binding site. Molecular dynamics simulations confirm that the structure of the C-terminal region is affected. In conclusion, we demonstrate for the first time evidence for auditory neuropathy in CAPOS syndrome, which may reflect impaired propagation of electrical impulses along the spiral ganglion neurons. This has implications for diagnosis and patient management. Auditory neuropathy is difficult to treat with conventional hearing aids, but preliminary improvement in speech perception in some patients suggests that cochlear implantation may be effective in CAPOS patients.

Natural history and retinal structure in patients with Usher syndrome type 1 owing to MYO7A mutation.

PURPOSE: To evaluate the phenotypic variability and natural history of ocular disease in a cohort of 28 individuals with MYO7A-related disease. Mutations in the MYO7A gene are the most common cause of Usher syndrome type 1, characterized by profound congenital deafness, vestibular arreflexia, and progressive retinal degeneration. DESIGN: Retrospective case series. PARTICIPANTS: Twenty-eight patients from 26 families (age range, 3-65 years; median, 32) with 2 likely disease-causing variants in MYO7A. METHODS: Clinical investigations included fundus photography, optical coherence tomography, fundus autofluorescence (FAF) imaging, and audiologic and vestibular assessments. Longitudinal visual acuity and FAF data (over a 3-year period) were available for 20 and 10 study subjects, respectively. MAIN OUTCOME MEASURES: Clinical, structural, and functional characteristics. RESULTS: All patients with MYO7A mutations presented with features consistent with Usher type 1. The median visual acuity for the cohort was 0.39 logarithm of the minimum angle of resolution (logMAR; range, 0.0-2.7) and visual acuity in logMAR correlated with age (Spearman's rank correlation coefficient, r = 0.71; P<0.0001). Survival analysis revealed that acuity ≤ 0.22 logMAR was maintained in 50% of studied subjects until age 33.9; legal blindness based on loss of acuity (≥ 1.00 logMAR) or loss of field (≤ 20°) was reached at a median age of 40.6 years. Three distinct patterns were observed on FAF imaging: 13 of 22 patients tested had relatively preserved foveal autofluorescence surrounded by a ring of high density, 4 of 22 had increased signal in the fovea with no obvious hyperautofluorescent ring, and 5 of 22 had widespread hypoautofluorescence corresponding to retinal pigment epithelial atrophy. Despite a number of cases presenting with a milder phenotype, there seemed to be no obvious genotype-phenotype correlation. CONCLUSIONS: MYO7A-related ocular disease is variable. Central vision typically remains preserved at least until the third decade of life, with 50% of affected individuals reaching legal blindness by 40 years of age. Distinct phenotypic subsets were identified on FAF imaging. A specific allele, previously reported in nonsyndromic deafness, may be associated with a mild retinopathy.

Alteration in auditory function during the ovarian cycle.

This study investigates whether physiological variations in ovarian hormones during the ovarian cycle (OC) are associated with changes in auditory function. Sixteen women with normal hearing underwent auditory tests and simultaneous measurements of the hormone levels four times during OC. The auditory tests included recording of otoacoustic emissions (OAEs), the medial olivocochlear (MOC) suppression and auditory brainstem responses (ABRs). The OC was defined by oestradiol and progesterone serum levels and menstrual cycle dating. A significant spontaneous OAE frequency shift [F(3,114.6)=15.8, p<0.001], with the greatest shift in the late follicular phase (highest oestrogen levels), was observed. Transient evoked OAE levels showed a consistent tendency in an increase in all frequency bands in the late follicular/early luteal stage and a decrease in the late follicular stage; TEOAE inter-session comparison indicated very small statistical differences. The MOC suppression changed significantly during OC [F(3,33.8)=3.2, p=0.036], with significant inter-session difference, lower in session 2 than in session 1 (p=0.019) and lower in session 4 than in session 1 (p=0.007). The ABR wave V absolute latency changed significantly during OC [F(3,33)=3.3, p=0.03], longer in the late follicular phase. There was also a significant positive correlation of TEOAEs and ABR (wave V latency and III-V interval) and significant negative correlation of MOC suppression with oestradiol levels in the follicular phase. The results of this study reflect very small changes in auditory function during OC, and they are suggestive of an increased hearing sensitivity around the time of ovulation.

Sudden sensorineural hearing loss.

Sudden sensorineural hearing loss is usually unilateral and can be associated with tinnitus and vertigo. In most cases the cause is not identified, although various infective, vascular, and immune causes have been proposed. A careful examination is needed to exclude life threatening or treatable causes such as vascular events and malignant diseases, and patients should be referred urgently for further assessment. About half of patients completely recover, usually in about 2 weeks. Many treatments are used, including corticosteroids, antiviral drugs, and vasoactive and oxygen-based treatments. Although no treatment is proven, we recommend a short course of oral high-dose corticosteroids. There is much to learn about pathogenesis of sudden sensorineural hearing loss, and more clinical trials are needed to establish evidence-based management.

Update on Usher syndrome.

PURPOSE OF REVIEW: The present review addresses the mechanisms, genetics and pathogenesis of Usher syndrome. RECENT FINDINGS: Recent molecular findings have provided more information regarding the pathogenesis of this disorder and the wide phenotypic variation in both audiovestibular and/or visual systems. Evidence has begun to emerge supporting a theory of a protein interactome involving the Usher proteins in both the inner ear and the retina. This interactome appears to be important for hair cell development in the ear but its role in the retina remains unclear. SUMMARY: Understanding clinical disease progression and molecular pathways is important in the progress towards developing gene therapy to prevent blindness due to Usher syndrome as well as delivering prognostic information to affected individuals.

Subjective visual vertical and horizontal: effect of the preset angle.

OBJECTIVES: (1) To study the subjective visual vertical (SVV) and subjective visual horizontal (SVH) in patients with long-standing unilateral peripheral vestibular dysfunction (PVD) and unilateral Ménière's disease (MD) compared with controls. (2) To study the relationship between the direction of deviation of the linear marker (preset angle) and measures of SVV and SVH values. DESIGN: Prospective case-control study. SETTING: Outpatient clinic in a tertiary neuro-otology department. PATIENTS: Seventeen healthy volunteers (mean age, 35.5 years), 9 patients with PVD (mean age, 43.1 years), and 10 patients with MD (mean age, 50.7 years) were included in the analysis. INTERVENTIONS: All subjects had a detailed neuro-otological evaluation. Twelve replicate readings of SVV and SVH were taken for each subject, with random preset angles, 6 in the clockwise and 6 in the counterclockwise direction. MAIN OUTCOME MEASURE: The SVV and SVH values were correlated with clinical features and the direction of the preset angle. RESULTS: The 2 subjects with PVD who had abnormal mean SVV and SVH values had symptoms of dysequilibrium and otolithic involvement. The 5 patients in the MD group who had abnormal mean SVV and SVH values had either recent acute vertiginous attacks or total canal paresis on the affected side. A previously unreported finding, to our knowledge, is that the SVV value depends on the direction of the preset angle in all subject groups, more so in the PVD and MD groups compared with controls. The SVV is inclined toward the direction of the preset angle. A weaker relation is seen between the SVH and preset angle. CONCLUSION: The preset angle should be considered when comparing SVV and SVH values.

The changing face of Usher syndrome: clinical implications.

Usher syndrome is both genetically and phenotypically heterogeneous. Traditionally, the condition has been classified into three clinical types, differentiated by the severity and progression of the hearing impairment and by the presence or absence of vestibular symptoms. Recent advances in molecular genetics have enabled researchers to study the phenotypic expression in confirmed molecular groups of Usher. In response to the expansion of clinical and genetic information on Usher, we report an up to date review of the different clinical forms of Usher in known molecular groups and use the emerging evidence to appraise the diagnostic utility of the traditional classification of Usher. Our findings undermine the traditional view that the clinical types of Usher have distinct genetic causes. The pleiotropic effects of some of the major causes of Usher lead to considerable overlap between the different clinical types, with very little evidence for phenotypic-genotypic correlations. The novel synthesis emerging from this review suggests more productive approaches to the diagnosis of Usher in hearing-impaired children which would provide more accurate prognostic information to families.