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.

The insula (Island of Reil) and its role in auditory processing. Literature review

The insular cortex is a complex structure which contains areas that subserve visceral sensory, motor, vestibular, and somatosensory functions. The role of the insular cortex in auditory processing was poorly understood until recently. However, recent case studies indicate that bilateral damage to the insulae may result in total auditory agnosia. Functional imaging studies demonstrate that the insulae participate in several key auditory processes, such as allocating auditory attention and tuning in to novel auditory stimuli, temporal processing, phonological processing and visual-auditory integration. These studies do not clarify the issue of further specialisation within the insular cortex, e.g. whether the posterior insulae are primarily sensory areas, while the anterior insulae serve mainly as integration/association auditory areas, two hypotheses that would be compatible with the cytoarchitectonic structure and connectivity of the insulae. The functional characterisation of the insulae remains incomplete, underlining the need for further studies.

Symptoms, anxiety and handicap in dizzy patients: development of the vertigo symptom scale

Questionnaires assessing symptoms, anxiety and handicap were completed by 127 vertiginous patients. Factor analysis identified four distinct symptom clusters which formed the basis for the construction of scales quantifying the number and frequency of symptoms of: (a) vertigo (of long and short duration); (b) autonomic sensations and anxiety arousal; and (c) somatization. Scores on the vertigo severity scale were significantly related to clinical diagnosis and had near-zero correlations with measures of anxiety. Vertigo severity, autonomic signs and depressed mood each independently contributed to variance in handicap, taking precedence over the relationship between handicap and trait and state anxiety. Our findings suggest that the familiar association between anxiety and vertigo may be mediated principally by autonomic symptomatology arising as a result of somatopsychic and psychosomatic processes.

Diabetes mellitus associated with a pathogenic point mutation in mitochondrial DNA

Family studies of diabetes mellitus (DM) show that patients are more likely to have affected mothers than affected fathers. Since the inheritance of mitochondrial (mtDNA), unlike nuclear DNA, is exclusively maternal, could it be that defect(s) in mtDNA account for some cases of DM? Such defects have been associated with rare neurological syndromes, in some of which DM has been an accompanying feature. We have looked for glucose intolerance and for a previously known point mutation of mtDNA in a family, some of whose members have a multisystem disorder with DM but not neurological involvement. DNA samples were obtained from fourteen family members. The point mutation (affecting position 3243 in the tRNA leucine mitochondrial gene) was found in all three diabetic patients and post mortem tissues in the proband; it was also found in seven offspring of female patients. It was not found in the two children of the male proband. The contribution of this mutation to DM in general is not known but clinicians ought to be aware of the possibility, especially in families with multisystem disease and maternal transmission.

Psychiatric morbidity in patients with peripheral vestibular disorder: a clinical and neuro-otological study

This study reports the psychiatric morbidity in 54 patients with objective evidence of peripheral vestibular disorder seen three to five years after their original referral. A third of the patients were free from vestibular symptoms at follow up and a further third had experienced some improvement. Two thirds of the patients had experienced psychiatric symptoms during this period, although only 50% were rated above the cut off point for significant psychiatric disturbance when interviewed. Panic disorder with or without agoraphobia and major depression were the commonest psychiatric diagnoses. Patients with classical "labyrinthine" symptoms had a more severe canal paresis than the rest, but the degree of the abnormalities in the neuro-otological tests was unrelated to outcome or to psychiatric morbidity. On the other hand, there was a significant correlation between the presence of vestibular symptoms and psychiatric morbidity, which in turn correlated with measures of anxiety, perceived stress and previous psychiatric illness.

Radiological malformations of the ear in Pendred syndrome

Pendred syndrome comprises the association of severe congenital sensorineural deafness with thyroid pathology. Although it is the commonest form of syndromic hearing loss, the primary genetic defect remains unknown. The variable clinical presentation allied to the difficulty in securing the diagnosis have resulted in relatively poor documentation of the radiological features of this syndrome. We now present data on 40 patients, all complying with strict diagnostic criteria for the disorder, and describe our experience of the prevalence of specific malformations of the inner ear as well as comparing the relative merits of computed tomography (CT) and magnetic resonance imaging (MRI) in the investigation of this inherited condition. Deficiency of the interscalar septum in the distal coils of the cochlea (Mondini deformity) was found to be a common but probably not a constant feature of Pendred syndrome. However, enlargement of the endolymphatic sac and duct in association with a large vestibular aqueduct was present in all 20 patients examined by MRI. We conclude that thin section high resolution MRI on a T2 protocol in the axial and sagittal planes is the imaging investigation of choice.

Molecular analysis of the PDS gene in Pendred syndrome

Pendred syndrome is an autosomal recessive disorder characterized by the association between sensorineural hearing loss and thyroid swelling or goitre and is likely to be the most common form of syndromic deafness. Within the thyroid gland of affected individuals, iodide is incompletely organified with variable effects upon thyroid hormone biosynthesis, whilst the molecular basis of the hearing loss is unknown. The PDS gene has been identified by positional cloning of chromosome 7q31, within the Pendred syndrome critical linkage interval and encodes for a putative ion transporter called pendrin. We have investigated a cohort of 56 kindreds, all with features suggestive of a diagnosis of Pendred syndrome. Molecular analysis of the PDS gene identified 47 of the 60 (78%) mutant alleles in 31 families (includes three homozygous consanguineous kindreds and one extended family segregating three mutant alleles). Moreover, four recurrent mutations accounted for 35 (74%) of PDS disease chromosomes detected and haplotype analysis would favour common founders rather than mutational hotspots within the PDS gene. Whilst these findings demonstrate molecular heterogeneity for PDS mutations associated with Pendred syndrome, this study would support the use of molecular analysis of the PDS gene in the assessment of families with congenital hearing loss.

Aetiology and clinical presentations of auditory processing disorders--a review

Auditory processing disorders may have detrimental consequences on a child's life, if undiagnosed and untreated. We review causes of auditory processing disorders in order to raise clinical awareness. Auditory processing disorders may present against a background of neurological disease or developmental disorders, as well as in isolation. Clinicians need to be aware of potential causes and implications of auditory processing disorders.

Comprehensive sequence analysis of nine Usher syndrome genes in the UK National Collaborative Usher Study

Background

Usher syndrome (USH) is an autosomal recessive disorder comprising retinitis pigmentosa, hearing loss and, in some cases, vestibular dysfunction. It is clinically and genetically heterogeneous with three distinctive clinical types (I–III) and nine Usher genes identified. This study is a comprehensive clinical and genetic analysis of 172 Usher patients and evaluates the contribution of digenic inheritance.

Methods

The genes MYO7A, USH1C, CDH23, PCDH15, USH1G, USH2A, GPR98, WHRN, CLRN1 and the candidate gene SLC4A7 were sequenced in 172 UK Usher patients, regardless of clinical type.

Results

No subject had definite mutations (nonsense, frameshift or consensus splice site mutations) in two different USH genes. Novel missense variants were classified UV1-4 (unclassified variant): UV4 is ‘probably pathogenic’, based on control frequency <0.23%, identification in trans to a pathogenic/probably pathogenic mutation and segregation with USH in only one family; and UV3 (‘likely pathogenic’) as above, but no information on phase. Overall 79% of identified pathogenic/UV4/UV3 variants were truncating and 21% were missense changes. MYO7A accounted for 53.2%, and USH1C for 14.9% of USH1 families (USH1C:c.496+1G>A being the most common USH1 mutation in the cohort). USH2A was responsible for 79.3% of USH2 families and GPR98 for only 6.6%. No mutations were found in USH1G, WHRN or SLC4A7.

Conclusions

One or two pathogenic/likely pathogenic variants were identified in 86% of cases. No convincing cases of digenic inheritance were found. It is concluded that digenic inheritance does not make a significant contribution to Usher syndrome; the observation of multiple variants in different genes is likely to reflect polymorphic variation, rather than digenic effects.

Interference between postural control and mental task performance in patients with vestibular disorder and healthy controls

OBJECTIVES

To determine whether interference between postural control and mental task performance in patients with balance system impairment and healthy subjects is due to general capacity limitations, motor control interference, competition for spatial processing resources, or a combination of these.

METHOD

Postural stability was assessed in 48 patients with vestibular disorder and 24 healthy controls while they were standing with eyes closed on (a) a stable and (b) a moving platform. Mental task performance was measured by accuracy and reaction time on mental tasks, comprising high and low load, spatial and non-spatial tasks. Interference between balancing and performing mental tasks was assessed by comparing baseline (single task) levels of sway and mental task performance with levels while concurrently balancing and carrying out mental tasks.

RESULTS

As the balancing task increased in difficulty, reaction times on both low load mental tasks grew progressively longer and accuracy on both high load tasks declined in patients and controls. Postural sway was essentially unaffected by mental activity in patients and controls.

CONCLUSIONS

It is unlikely that dual task interference between balancing and mental activity is due to competition for spatial processing resources, as levels of interference were similar in patients with vestibular disorder and healthy controls, and were also similar for spatial and non-spatial tasks. Moreover, the finding that accuracy declined on the high load tasks when balancing cannot be attributed to motor control interference, as no motor control processing is involved in maintaining accuracy of responses. Therefore, interference between mental activity and postural control can be attributed principally to general capacity limitations, and is hence proportional to the attentional demands of both tasks.

Pendred syndrome--100 years of underascertainment?

Pendred syndrome is an autosomal recessive condition classically characterized by deafness and goitre. Since both cochlear and thyroid pathology are required to secure the diagnosis, it is unclear whether the condition might present without the classical features. The perchlorate discharge test, the gold-standard investigation for Pendred syndrome, is non-specific, and in the absence of alternative means of confirming the diagnosis, its sensitivity is unknown. We used the recent mapping of the gene to chromosome 7q to identify pedigrees with a likely diagnosis of Pendred syndrome, and assessed the prevalence of clinical parameters of disease in affected patients. Thirty-six familial cases showed co-segregation between disease and the Pendred syndrome locus on chromosome 7q. Clinical and investigative findings were compared in index cases (n = 18) vs. affected siblings (n = 18). The overall prevalence of goitre was 73%, higher in index cases (94%) than in siblings (56%), many of whom had not previously been considered to have the condition. One perchlorate discharge test was false-negative (2.9%). Radiological malformations of the cochlea were identified in 86% of cases. Securing a diagnosis of Pendred syndrome may be difficult, especially in the single case. The perchlorate discharge test, although valuable, is difficult to undertake in the younger patient, and radiology may assist in diagnosing such patients.

Bilateral loss of vestibular function: clinical findings in 53 patients

The clinical presentations and aetiologies of a series of 53 cases of bilateral vestibular failure (BVF) seen by the authors over a decade were evaluated by retrospective review of the medical records. Thirty-nine per cent of patients had associated neurological disease; 13% had a progressive cerebellar syndrome with disabling gait ataxia, abnormal eye movements and cerebellar atrophy on neuro-imaging. BVF was usually unsuspected. Nine per cent had cranial or peripheral neuropathies and in this group there was no abnormality of brain stem/cerebellar oculomotor function, but hearing loss was common. Eleven per cent revealed BVF and hearing loss secondary to meningitis, and 6% had other neurological disorders. Idiopathic BVF was found in 21% of cases, characterised by paroxysmal vertigo and/or oscillopsia, but no abnormal clinical signs. Gentamicin ototoxicity accounted for a further 17%, while autoimmune disease was present in 9% of patients. Otological or neoplastic disease was diagnosed in the remaining 13% of patients. It was concluded that neurological, audiological and ocular motor assessments allow the probable cause of BVF to be defined in approximately 80% of cases. A group of BVF related to autoimmune pathologies is reported for the first time, indicating the need for immunological screening. Idiopathic BVF may present with only minor visual or vestibular symptoms, while in patients with cerebellar degeneration, BVF may be unsuspected and, thus, underdiagnosed.

Oculomotor function in multiple system atrophy: clinical and laboratory features in 30 patients

We reviewed the clinical and laboratory oculomotor features in 30 patients with probable multiple system atrophy (MSA), 22 with MSA-P and 8 with MSA-C. Six patients were also examined post mortem, MSA being confirmed in four and excluded in two (Parkinson's disease and progressive supranuclear palsy). Clinical examination showed the following abnormalities; excessive square wave jerks--21 of 30 patients; mild vertical supranuclear gaze palsy--8 of 30; gaze-evoked nystagmus--12 of 30 patients, three of whom had no extraocular evidence of cerebellar dysfunction; positioning downbeat nystagmus--10 of 25; mild or moderate saccadic hypometria--22 of 30; impaired ("broken up") smooth pursuit--28 of 30; reduced VOR suppression--16 of 24. Electro-oculography and caloric testing did not add significant extra information. In patients presenting with an akinetic-rigid syndrome it can be difficult to differentiate idiopathic Parkinson's disease from MSA-P and other causes of atypical parkinsonism. Our findings suggest that the presence of excessive square wave jerks, mild-moderate hypometria of saccades, impaired VOR suppression, spontaneous nystagmus or positioning downbeat nystagmus may be oculomotor "red flags" or clues to the presence of MSA. Further, the presence of clinically slow saccades, or moderate-to-severe gaze restriction, suggests a diagnosis other than MSA.

Neuro-otological and psychiatric abnormalities in a community sample of people with dizziness: a blind, controlled investigation

OBJECTIVES

To determine neurootological and psychiatric abnormalities associated with complaints of dizziness in an epidemiological community sample of people of working age, and the extent of comorbidity between neuro-otological and psychiatric dysfunction.

METHOD

A survey of 3884 people randomly selected from six general practice lists identified 262 people with significant dizziness, from which a subsample of 15 men and 22 women were recruited for testing. Dizzy subjects were evaluated by blind neuro-otological testing, computerised dynamic posturography, a computerised psychiatric assessment, neuro-otological and general medical examination, and diagnosis. An age matched control group of 18 men and 22 women underwent the same evaluation.

RESULTS

Tests of auditory, vestibular, and oculo-motor function did not discriminate between dizzy subjects and controls, but dizzy subjects had significantly worse balance on posturographic testing, more diagnoses of medical disorder, and a higher prevalence of psychiatric morbidity.

CONCLUSIONS

The findings suggest that dizziness in the community is typically characterised by mild physical disorder accompanied by some psychiatric disturbance. As the combination of minor physical and psychiatric disorder is known to be unusually persistent and handicapping, treatment programmes must be provided for this prevalent syndrome, perhaps by a partnership between primary care and neuro-otological and psychiatric hospital outpatient clinics with experience and expertise in the diagnosis and management of dizziness and psychiatric disturbance.

Dizziness following head injury: a neuro-otological study

Dizziness is a frequent and debilitating complications of head injury and accounts for increasing numbers of medico-legal claims. A detailed neuro-otological study was carried out from the records of 100 patients with post-traumatic dizziness to explore the neuro-otological basis of their symptoms: 50 patients presenting for medico-legal purposes (group I) and 50 presenting for management of their vestibular symptoms (group II). The two groups showed a similar sex distribution, a similar range of causes of head injury and similar severity of head injury (72 minor, 24 moderate and 4 severe). Of the 100, 88 showed at least one audio-vestibular abnormality on testing. Vertigo of the benign positional paroxysmal type was the commonest vestibular diagnosis in both groups (61/100), and only 8 patients showed central vestibular abnormalities. Fifty-three patients had audiometric abnormalities attributable to the head injury, the commonest of which was a high-tone sensorineural hearing loss. There was no significant difference in the incidence of any of the abnormalities in the medico-legal group (group I) when compared with the symptom management group (group II). The results provide strong evidence for an organic basis to recurring dizziness after head injury, whether or not a claim for compensation is pending, and emphasize the need for specialist neuro-otological investigation if abnormalities are to be identified and managed correctly.

Auditory temporal processing deficits in patients with insular stroke

OBJECTIVE

To assess central auditory function in a series of patients with stroke of the insula and adjacent areas.

METHODS

The authors recruited eight patients with stroke affecting the insula and adjacent areas and eight neurologically normal controls (matched to the patients for age, sex, handedness, and hearing thresholds). The lesion spared the adjacent auditory areas in three patients and included other auditory structures in five cases. The authors conducted pure-tone audiometry and tympanometry and a central auditory test battery, which included the dichotic digits, and three temporal tests, the duration pattern, frequency pattern, and gaps in noise tests. They collected information from the hospital notes on symptoms at presentation and neuropsychological assessment data during the acute phase.

RESULTS

The central auditory tests gave normal results in all controls. The temporal tests gave abnormal results in all three cases in which other auditory areas were spared, as well as in the other five cases. Results of the gaps in noise test were abnormal contralaterally to the lesion in three and bilaterally in five cases. The central auditory deficits did not cosegregate with the presence of cognitive impairment during the acute stage.

CONCLUSION

Insular lesions may affect central auditory function and, in particular, temporal resolution and sequencing, consistent with neuroimaging studies.

A detailed clinical and molecular survey of subjects with nonsyndromic USH2A retinopathy reveals an allelic hierarchy of disease-causing variants

Defects in USH2A cause both isolated retinal disease and Usher syndrome (ie, retinal disease and deafness). To gain insights into isolated/nonsyndromic USH2A retinopathy, we screened USH2A in 186 probands with recessive retinal disease and no hearing complaint in childhood (discovery cohort) and in 84 probands with recessive retinal disease (replication cohort). Detailed phenotyping, including retinal imaging and audiological assessment, was performed in individuals with two likely disease-causing USH2A variants. Further genetic testing, including screening for a deep-intronic disease-causing variant and large deletions/duplications, was performed in those with one likely disease-causing change. Overall, 23 of 186 probands (discovery cohort) were found to harbour two likely disease-causing variants in USH2A. Some of these variants were predominantly associated with nonsyndromic retinal degeneration (‘retinal disease-specific'); these included the common c.2276 G>T, p.(Cys759Phe) mutation and five additional variants: c.2802 T>G, p.(Cys934Trp); c.10073 G>A, p.(Cys3358Tyr); c.11156 G>A, p.(Arg3719His); c.12295-3 T>A; and c.12575 G>A, p.(Arg4192His). An allelic hierarchy was observed in the discovery cohort and confirmed in the replication cohort. In nonsyndromic USH2A disease, retinopathy was consistent with retinitis pigmentosa and the audiological phenotype was variable. USH2A retinopathy is a common cause of nonsyndromic recessive retinal degeneration and has a different mutational spectrum to that observed in Usher syndrome. The following model is proposed: the presence of at least one ‘retinal disease-specific' USH2A allele in a patient with USH2A-related disease results in the preservation of normal hearing. Careful genotype–phenotype studies such as this will become increasingly important, especially now that high-throughput sequencing is widely used in the clinical setting.

Benefits and challenges of newborn hearing screening for developing countries

The late detection of permanent congenital and early-onset hearing loss (PCEHL) often has severe effects on linguistic, speech, cognitive and educational development in affected children. Since newborn hearing screening (NHS) allows most PCEHL to be detected early enough for optimal intervention, the prospects of its introduction in the developing world are reviewed in this paper. It is observed that a simple generalisation on the feasibility of NHS for the developing countries seems inappropriate in view of the diversities in the health and socio-economic status of these countries and the recent favourable reports of universal newborn hearing screening from the region. NHS empowers parents to make timely choices that will allow their hearing impaired children to be given a good start in life and be fully integrated into the wider community. It also compels attention towards the development of essential hearing healthcare services, besides the specific documented benefits. Existing child-healthcare structures such as the expanded programme on immunisation (EPI), baby friendly hospital initiatives (BFHI) and integrated management of childhood illness (IMCI) provide opportunities for the introduction of some form of NHS in many of these countries where routine or systematic childhood hearing screening does not exist. Limited funding, manpower shortages, inadequate support services, low public awareness and the uncertainty regarding the commitment from healthcare practitioners may present some challenges but these are not insurmountable. Pilot studies are necessary in each country to provide empirical data that will guide healthcare providers who wish to introduce such a programme at any level of healthcare delivery.

Relationship between balance system function and agoraphobic avoidance

There is a striking similarity between the situations avoided by people with agoraphobia and the environments which provoke disorientation in people with organic balance disorders. This study investigated the possibility that agoraphobia might be linked to balance system dysfunction by comparing the results of balance system tests in 36 people with symptoms of panic and agoraphobia and 20 normal controls. A traditional battery of audiovestibular tests was supplemented with moving platform posturography, which assesses the postural instability induced by disorienting perceptual conditions. Subjects also completed questionnaire measures of somatic symptoms of dizziness and anxiety, agoraphobic cognitions, avoidance behaviour and state anxiety. Over 60% of the Ss with symptoms of panic and agoraphobia were destabilised by the disorienting perceptual conditions, compared with just 10% of the normal controls. Postural instability was strongly related to reported agoraphobic avoidance (r = 0.63, P < 0.01), even after controlling for symptoms, anxiety and agoraphobic cognitions. In our discussion we consider alternative interpretations of these findings, future directions for research, and implications for therapy.

Vestibular hypersensitivity to clicks is characteristic of the Tullio phenomenon

OBJECTIVES

The frequency of pathologically reduced click thresholds for vestibular activation was explored in patients with the Tullio phenomenon (sound induced vestibular activation).

METHODS

Seven patients (eight affected ears) with symptoms of oscillopsia and unsteadiness in response to loud external sounds or to the patient's own voice were examined. In all but one patient, vestibular hypersensitivity to sound was confirmed by the fact that eye movements could be produced by pure tones of 110 dB intensity or less. Conventional diagnostic imaging was normal in all cases and three of the patients had normal middle ears at surgical exploration. Thresholds for click evoked vestibulocollic reflexes were compared with those of a group of normal subjects. Galvanic stimulation was used as a complementary method of examining the excitability of vestibular reflexes.

RESULTS

All the patients showed a reduced threshold for click activation of vestibulocollic reflexes arising from the affected ear. Short latency EMG responses to clicks were also present in posterior neck and leg muscles, suggesting that these muscles receive vestibular projections. Galvanic stimulation produced a normal pattern of body sway in four of the five patients tested.

CONCLUSIONS

A pathologically reduced threshold to click activation (< or = 70 dB NHL (average normal hearing level)) seems to be a consistent feature of the Tullio phenomenon and a useful diagnostic criterion. This in turn is most likely to be due to an increased effectiveness of the transmission of sound energy to saccular receptors. Activation of these receptors probably contributed to the vestibular symptoms experienced by the patients.

Tinnitus after head injury: evidence from otoacoustic emissions

OBJECTIVE

Tinnitus may be caused by a lesion or dysfunction at any level of the auditory system. This study explores cochlear mechanics using otoacoustic emissions in patients with tinnitus after head injury, in whom there seems to be evidence to support dysfunction within the CNS.

METHODS

The study included 20 patients with tinnitus and other auditory symptoms, such as hyperacusis and difficulty in listening in background noise, after head injury, in the presence of an "intact" auditory periphery (normal or near normal audiometric thresholds). They were compared with 20 normal subjects and 12 subjects with head injury, but without tinnitus, who had similar audiometric thresholds. In all subjects otoacoustic emissions, including transient click-evoked (TEOAEs) and spontaneous otoacoustic emissions (SOAEs), were recorded, and a test of efferent medial olivocochlear suppression, consisting of recording of TEOAEs under contralateral stimulation, was performed.

RESULTS

A significantly higher prevalence of SOAEs (100%), higher TEOAE response amplitudes, and reduced medial olivocochlear suppression in patients with tinnitus in comparison with subjects without tinnitus have been found.

CONCLUSION

These findings have been interpreted to be an extracochlear phenomenon, in which the reduction in central efferent suppression of cochlear mechanics, leading to an increase in cochlear amplifier gain, was subsequent to head injury. Auditory symptoms in these patients seemed to constitute the "disinhibition syndrome".

Immune-mediated inner-ear disorders in neuro-otology

PURPOSE OF REVIEW

Immune-mediated inner-ear disorders may present to different medical disciplines and new research findings emerge rapidly. The purpose of this review is to draw the different strands together to produce an overview describing the clinical presentation of immune-mediated inner-ear disorders and to discuss useful diagnostic criteria with a focus on tissue-specific and tissue-non-specific antibodies.

RECENT FINDINGS

The importance of diagnosing an immune-mediated inner-ear disorder is highlighted in the context of it being one of few forms of treatable inner-ear disorder with a good response to immunosuppressive therapy. Due to a lack of reliable tests, the criteria upon which the diagnosis of immune-mediated inner-ear disease is based are often arbitrary. Previous and current research focuses mainly on the investigation of the aetiology of immune-mediated disorders, studying the presence of autoantibodies and the antigens responsible for their production. The prognostic and therapeutic values of inner-ear-specific antibodies are still unclear. Various antigens have been suggested. However, most antigens identified have been ubiquitous proteins not specific to the inner ear and therefore lack logical association with localized inner-ear pathology.

SUMMARY

Early diagnosis of immune-mediated inner-ear disorders with prompt treatment may prevent irreversible damage to inner-ear structures. Accordingly, it is important to include immune-mediated inner-ear disorders in the differential diagnosis of patients presenting with 'idiopathic' audiovestibular dysfunction. To enable early diagnosis, we recommend that the current available routine immunological laboratory tests (antinuclear, antineutrophil cytoplasmic, antiendothelial cell, antiphospholipid/anticardiolipin and antithyroid antibodies) are used when assessing a patient with suspected immune-mediated inner-ear disorder.

Auditory interhemispheric transfer deficits, hearing difficulties, and brain magnetic resonance imaging abnormalities in children with congenital aniridia due to PAX6 mutations

OBJECTIVE

To assess auditory processing, hearing difficulties, and brain magnetic resonance (MR) imaging abnormalities in children with panocular developmental aniridia due to PAX6 mutations.

DESIGN

Case-control study.

SETTING

Great Ormond Street Hospital and Institute of Child Health.

PARTICIPANTS

Eleven case subjects with PAX6 mutations and 11 age-matched and sex-matched healthy control subjects.

INTERVENTIONS

All subjects completed a structured hearing questionnaire, baseline audiometry, and central auditory tests (dichotic speech tests, frequency and duration pattern tests, and gaps-in-noise test). Case subjects underwent brain MR imaging with volumetry, and the results were compared with those of age-matched and sex-matched healthy control subjects randomly selected from the Radiology and Physics Unit database.

MAIN OUTCOME MEASURES

Brain MR imaging, central auditory test results, and questionnaire scores.

RESULTS

The corpus callosum area was significantly smaller on brain volumetry in the cases compared with the controls. The anterior commissure was small in 7 cases and was normal in 3 cases on visual inspection of brain MR images (conducted in 10 of 11 cases). Audiograms showed no abnormalities in any of the children. Central auditory test results were normal in all the controls and were abnormal in all the cases except for 1 case with a pattern of abnormalities consistent with reduced auditory interhemispheric transfer. The cases had greater difficulty localizing sound and understanding speech in noise than the controls.

CONCLUSIONS

Despite normal audiograms, children with PAX6 mutations may experience auditory interhemispheric transfer deficits and have difficulty localizing sound and understanding speech in noise. In view of their additional visual difficulties, thorough audiological evaluation of these children is indicated to initiate appropriate management.

The effect of virtual reality on visual vertigo symptoms in patients with peripheral vestibular dysfunction: a pilot study

Individuals with vestibular dysfunction may experience visual vertigo (VV), in which symptoms are provoked or exacerbated by excessive or disorientating visual stimuli (e.g. supermarkets). VV can significantly improve when customized vestibular rehabilitation exercises are combined with exposure to optokinetic stimuli. Virtual reality (VR), which immerses patients in realistic, visually challenging environments, has also been suggested as an adjunct to VR to improve VV symptoms. This pilot study compared the responses of sixteen patients with unilateral peripheral vestibular disorder randomly allocated to a VR regime incorporating exposure to a static (Group S) or dynamic (Group D) VR environment. Participants practiced vestibular exercises, twice weekly for four weeks, inside a static (Group S) or dynamic (Group D) virtual crowded square environment, presented in an immersive projection theatre (IPT), and received a vestibular exercise program to practice on days not attending clinic. A third Group D1 completed both the static and dynamic VR training. Treatment response was assessed with the Dynamic Gait Index and questionnaires concerning symptom triggers and psychological state. At final assessment, significant between-group differences were noted between Groups D (p=0.001) and D1 (p=0.03) compared to Group S for VV symptoms with the former two showing a significant 59.2% and 25.8% improvement respectively compared to 1.6% for the latter. Depression scores improved only for Group S (p=0.01) while a trend towards significance was noted for Group D regarding anxiety scores (p=0.07).

CONCLUSION

Exposure to dynamic VR environments should be considered as a useful adjunct to vestibular rehabilitation programs for patients with peripheral vestibular disorders and VV symptoms.