Progressive auditory neuropathy in patients with Leber's hereditary optic neuropathy

Objective: To investigate auditory neural involvement in patients with Leber's hereditary optic neuropathy (LHON).Methods: Auditory assessment was undertaken in two patients with LHON. One was a 45 year old woman with Harding disease (multiple-sclerosis-like illness and positive 11778mtDNA mutation) and mild auditory symptoms, whose auditory function was monitored over five years. The other was a 59 year old man with positive 11778mtDNA mutation, who presented with a long standing progressive bilateral hearing loss, moderate on one side and severe to profound on the other. Standard pure tone audiometry, tympanometry, stapedial reflex threshold measurements, stapedial reflex decay, otoacoustic emissions with olivo-cochlear suppression, auditory brain stem responses, and vestibular function tests were undertaken.Results: Both patients had good cochlear function, as judged by otoacoustic emissions ( intact outer hair cells) and normal stapedial reflexes ( intact inner hair cells). A brain stem lesion was excluded by negative findings on imaging, recordable stapedial reflex thresholds, and, in one of the patients, olivocochlear suppression of otoacoustic emissions. The deterioration of auditory function implied a progressive course in both cases. Vestibular function was unaffected.Conclusions: The findings are consistent with auditory neuropathy - a lesion of the cochlear nerve presenting with abnormal auditory brain stem responses and with normal inner hair cells and the cochlear nucleus (lower brain stem). The association of auditory neuropathy, or any other auditory dysfunction, with LHON has not been recognised previously. Further studies are necessary to establish whether this is a consistent finding

The Future of ORL-HNS and Associated Specialties Series: The future of audiological rehabilitation

The field of audiological rehabilitation in adults faces an array of opportunities. Some of these are technological, as with the advent of fully digital hearing-aids, and some involve clinical practice, such as opportunities for true multidisciplinary working, and for changes in hearing-aid prescription and provision. The development of well-validated questionnaire instruments should facilitate robust research into the effectiveness of clinical interventions in adult audiological rehabilitation, for such evidence is urgently needed if the field is to thrive

Misdiagnosis of hearing loss due to ear canal collapse: A report of two cases

Collapse of the external auditory meatus during audiometry can lead to spuriously increased hearing thresholds : being obtained, particularly at high frequencies, and may simulate conditions such as noise-induced hearing loss, presbyacusis and retrocochlear pathology. Consequently, inappropriate investigations and management may be undertaken. Two patients with elevated thresholds secondary to ear canal collapse are described. The implications of initially failing to identify the true nature of their 'hearing losses' are highlighted and strategies to avoid such pitfalls are discussed

Audiovestibular manifestations of the antiphospholipid syndrome

We report on two patients who have high titres of antiphospholipid antibodies, both of whom had acute audiovestibular failure. One of the patients had systemic lupus erythematosus. The other patient had primary antiphospholipid syndrome: audiovestibular symptoms have not been reported in this condition. The occurrence of acute audiovestibular failure in the primary antiphospholipid syndrome raises the question as to whether patients presenting with acute deafness or vestibular disturbance should be screened for the presence of anticardiolipin antibodies

Labyrinthine involvement in Behcet's syndrome

We report the neuro-otological findings in 26 consecutive patients with definite and probable Behcet's syndrome unselected for audiovestibular complaints. Auditory and/or vestibular abnormalities were found in 19 (73 per cent) patients, with auditory involvement in 14 (54 per cent) and vestibular in 10 (38.5 per cent) of patients. Peripheral involvement was more common than central involvement for both auditory and vestibular lesions. Bilateral cochlear hearing impairment was the most common audiological finding, whereas unilateral peripheral dysfunction was the prevailing vestibular abnormality. No correlation has been found between audiovestibular lesions and other organ lesions, disease duration or age or sex of the patients. Moreover, there was a lack of interdependence between cochlear and vestibular labyrinthine lesions. We conclude that a full neuro-otological assessment in patients under investigation for Behcet's syndrome may reveal labyrinth involvement in a substantial proportion of patients. In view of the absence of a specific diagnostic test for Behcet's syndrome, audiovestibular lesions may provide further diagnostic support for this disorder

Large endolymphatic sac. A congenital deformity of the inner ear shown by magnetic resonance imaging

Fluctuant and progressive hearing impairment in a patient with a wide vestibular aqueduct has been called the 'large vestibular aqueduct syndrome'. Recently reports of magnetic resonance imaging (MRI) studies describe enlargement of the endolymphatic sac and duct in patients shown to have large vestibular aqueducts by computed tomography (CT). A patient with progressive deafness was shown to have borderline or slightly enlarged vestibular aqueducts by re-formatted sagittal CT. However, MRI in axial and sagittal planes gave a more satisfactory demonstration of both aqueduct and endolymphatic sac enlargement

Clinical value of tone burst vestibular evoked myogenic potentials at threshold in acute and stable Ménière's disease

Introduction: The objectives of this preliminary, prospective, cohort study were to ascertain the characteristics of vestibular evoked myogenic potentials at threshold levels in two groups of Ménière's disease patients – acute and stable – and to identify whether vestibular evoked myogenic potentials can provide any specific, objective information to distinguish acute from stable Ménière's disease. Subjects and methods: The study was based at a tertiary neuro-otology centre. Twenty adult patients who fulfilled the American Academy of Otolaryngology–Head and Neck Surgery1 criteria for Ménière's disease were divided into two groups: 11 patients with acute Ménière's disease and nine patients with stable Ménière's disease. Eighteen healthy adult volunteers served as controls. All subjects underwent vestibular evoked myogenic potential testing with ipsilateral, short tone burst stimuli at 500 Hz, as well as pure tone audiometry. The patients also underwent caloric testing. Results: Vestibular evoked myogenic potentials were present in all controls, and were present in 65 per cent of patients but absent in 35 per cent. The mean absolute threshold (Tvestibular evoked myogenic potential) ± standard deviation in normal controls was 116 ± 7.7 dBSPL; this did not differ statistically from that in patients, nor did it differ between acute and stable Ménière's disease. The p13/n23 latencies at the threshold levels in the normal, acute and stable groups (mean ± standard deviation) were respectively: 15 ± 2.2 ms/23.0 ± 2.5 ms; 15.7 ± 0.9 ms/23.7 ± 0.9 ms; and 15.3 ± 2.0 ms/24.2 ± 1.9 ms. The mean interaural amplitude difference ratio (IAD) ± standard deviation was significantly higher in the stable group compared with the acute group (0.54 ± 0.33 vs −0.15 ± 0.22; p = 0.007) and with the controls (0.54 ± 0.33 vs 0.1 ± 0.22; p = 0.05). Conclusions: The parameter that best differentiated acute from stable Ménière's disease at threshold was the interaural amplitude difference ratio. Therefore, this parameter may be used to monitor the clinical course of Ménière's disease

Diagnostic accuracy and usability of the EMBalance decision support system for vestibular disorders in primary care: proof of concept randomised controlled study results

BACKGROUND: Dizziness and imbalance are common symptoms that are often inadequately diagnosed or managed, due to a lack of dedicated specialists. Decision Support Systems (DSS) may support first-line physicians to diagnose and manage these patients based on personalised data. AIM: To examine the diagnostic accuracy and application of the EMBalance DSS for diagnosis and management of common vestibular disorders in primary care. METHODS: Patients with persistent dizziness were recruited from primary care in Germany, Greece, Belgium and the UK and randomised to primary care clinicians assessing the patients with (+ DSS) versus assessment without (- DSS) the EMBalance DSS. Subsequently, specialists in neuro-otology/audiovestibular medicine performed clinical evaluation of each patient in a blinded way to provide the "gold standard" against which the + DSS, - DSS and the DSS as a standalone tool (i.e. without the final decision made by the clinician) were validated. RESULTS: One hundred ninety-four participants (age range 25-85, mean = 57.7, SD = 16.7 years) were assigned to the + DSS (N = 100) and to the - DSS group (N = 94). The diagnosis suggested by the + DSS primary care physician agreed with the expert diagnosis in 54%, compared to 41.5% of cases in the - DSS group (odds ratio 1.35). Similar positive trends were observed for management and further referral in the + DSS vs. the - DSS group. The standalone DSS had better diagnostic and management accuracy than the + DSS group. CONCLUSION: There were trends for improved vestibular diagnosis and management when using the EMBalance DSS. The tool requires further development to improve its diagnostic accuracy, but holds promise for timely and effective diagnosis and management of dizzy patients in primary care. TRIAL REGISTRATION NUMBER: NCT02704819 (clinicaltrials.gov)

Epithelial Cell Stretching and Luminal Acidification Lead to a Retarded Development of Stria Vascularis and Deafness in Mice Lacking Pendrin

Loss-of-function mutations of SLC26A4/pendrin are among the most prevalent causes of deafness. Deafness and vestibular dysfunction in the corresponding mouse model, Slc26a4−/−, are associated with an enlargement and acidification of the membranous labyrinth. Here we relate the onset of expression of the HCO3− transporter pendrin to the luminal pH and to enlargement-associated epithelial cell stretching. We determined expression with immunocytochemistry, cell stretching by digital morphometry and pH with double-barreled ion-selective electrodes. Pendrin was first expressed in the endolymphatic sac at embryonic day (E) 11.5, in the cochlear hook-region at E13.5, in the utricle and saccule at E14.5, in ampullae at E16.5, and in the upper turn of the cochlea at E17.5. Epithelial cell stretching in Slc26a4−/− mice began at E14.5. pH changes occurred first in the cochlea at E15.5 and in the endolymphatic sac at E17.5. At postnatal day 2, stria vascularis, outer sulcus and Reissner's membrane epithelial cells, and utricular and saccular transitional cells were stretched, whereas sensory cells in the cochlea, utricle and saccule did not differ between Slc26a4+/− and Slc26a4−/− mice. Structural development of stria vascularis, including vascularization, was retarded in Slc26a4−/− mice. In conclusion, the data demonstrate that the enlargement and stretching of non-sensory epithelial cells precedes luminal acidification in the cochlea and the endolymphatic sac. Stretching and luminal acidification may alter cell-to-cell communication and lead to the observed retarded development of stria vascularis, which may be an important step on the path to deafness in Slc26a4−/− mice, and possibly in humans, lacking functional pendrin expression