Auditory Neuropathy Spectrum Disorder Progressing with Motor and Sensory Neuropathy Caused by an ATP1A1 Variant

We encountered a 27-year-old Japanese woman with sensorineural deafness progressing to motor and sensory neuropathy. At 16 years old, she had developed weakness in her lower extremities and hearing impairment, which gradually deteriorated. At 22 years old, combined audiological, electrophysiological, and radiological examination results were consistent with auditory neuropathy spectrum disorder (ANSD). Genetic analyses identified a previously reported missense variant in the ATP1A1 gene (NM_000701.8:c.1799C>G, p.Pro600Arg). Although sensorineural deafness has been reported as a clinical manifestation of ATP1A1-related disorders, our case suggested that ANSD may underlie the pathogenesis of deafness in ATP1A1-related disorders. This case report broadens the genotype-phenotype spectrum of ATP1A1-related disorders.

Novel Pathogenic Variants in PJVK, the Gene Encoding Pejvakin, in Subjects with Autosomal Recessive Non-Syndromic Hearing Impairment and Auditory Neuropathy Spectrum Disorder

Pathogenic variants in the PJVK gene cause the DFNB59 type of autosomal recessive non-syndromic hearing impairment (AR-NSHI). Phenotypes are not homogeneous, as a few subjects show auditory neuropathy spectrum disorder (ANSD), while others show cochlear hearing loss. The numbers of reported cases and pathogenic variants are still small to establish accurate genotype-phenotype correlations. We investigated a cohort of 77 Spanish familial cases of AR-NSHI, in whom DFNB1 had been excluded, and a cohort of 84 simplex cases with isolated ANSD in whom OTOF variants had been excluded. All seven exons and exon-intron boundaries of the PJVK gene were sequenced. We report three novel DFNB59 cases, one from the AR-NSHI cohort and two from the ANSD cohort, with stable, severe to profound NSHI. Two of the subjects received unilateral cochlear implantation, with apparent good outcomes. Our study expands the spectrum of PJVK mutations, as we report four novel pathogenic variants: p.Leu224Arg, p.His294Ilefs*43, p.His294Asp and p.Phe317Serfs*20. We review the reported cases of DFNB59, summarize the clinical features of this rare subtype of AR-NSHI and discuss the involvement of PJVK in ANSD.

[Auditory evoked potentials in children with auditory neuropathy spectrum disorder]

The objective of the present study was to estimate peculiarities of the auditory brainstem evoked potentials (ABR), auditory steady-state responses (ASSR) and cortical auditory evoked potentials (CAEP) in the children presenting with bilateral auditory neuropathy spectrum disorder (ANSD). The study included 100 patients with bilateral ANSD diagnosed based on the positive response of otoacoustic emissions (OAEs) and/or cochlear microphonic (CM) detection, while no synchronous neural activity was detected in the ABR test. Cochlear microphonic was the main clue for the ANSD diagnosing, because OAE was absent in both ears of 49 children. ABR testing revealed no response bilaterally in 72 cases (out of 100). In contrast to ABR, the ASSR thresholds were detectable at all the four main frequencies in both ears in 73 % of the cases (47 out of the 64 tested ones). Both ABR and ASSR in most cases were incomparable with the behavioral audiometric thresholds. 28 children underwent CAEP testing. In 7 cases out of 8 with mild hearing loss detectable CAEP were recorded. CAEP registration in l7 children making use of the hearing aids and in 3 children after cochlear implantation revealed, in the majority of the cases, the concordance between CAEP detectability with behavioral thresholds and rehabilitation outcomes with fairly good speech intelligibility. It is concluded that the ABR registration with CM evaluation is the most informative test for ANSD diagnosis. However, ABR as well as ASSR is useless for the estimation of the behavioral thresholds. The results of this study suggest that the presence or absence of CAEPs can provide some indication of the audibility of a speech sound in the children with ANSD; however this method requires further investigation.

A novel missense mutation in the C2C domain of otoferlin causes profound hearing impairment in an Omani family with auditory neuropathy

OBJECTIVES

To identify genetic defects in an Omani family diagnosed with deafness. 

METHODS

A cross-sectional association study was conducted at the Department of Biochemistry, College of Medicine and Health Sciences, Sultan Qaboos University, Al-Khoud, Oman and the Centre of Medical Genetics, University of Antwerp, Antwerp, Belgium between August 2010 and September 2014. Microsatellites markers for nine non-syndromic genes were used to genotype the defective locus using the extracted DNA from family members. Sanger sequencing method was used to identify the disease causative mutation. Eazy linkage 5.05 was used to calculate the logarithm of odds score. Lasergene suite was used to detect the mutation position, and Phyre2, SMART, Rasmol, and GOR IV were used to predict the effects of the defect on protein structure and function. 

RESULTS

The disease was linked to markers located on chromosome-2 and covering the OTOF (DFNB9) gene. A novel missense mutation that changed nucleotide C to G at position c.1469 and consequently the amino acid Proline to Arginine (P490R) on exon 15 was detected. Protein modeling analysis revealed the impact of the mutation on protein structure and the relevant C2C domain. The mutation seems to create a new protein isoform homologous to the complement component C1q. 

CONCLUSION

These findings suggest that the mutation found in C2C domain of the OTOF gene is likely to cause deafness in the studied family reflecting the importance of C2 domains of otoferlin in hearing loss.

Unbound Bilirubin and Auditory Neuropathy Spectrum Disorder in Late Preterm and Term Infants with Severe Jaundice

OBJECTIVE

This study evaluates whether unbound bilirubin is a better predictor of auditory neuropathy spectrum disorder (ANSD) than total serum bilirubin (TSB) or the bilirubin:albumin molar ratio (BAMR) in late preterm and term neonates with severe jaundice (TSB ≥20 mg/dL or TSB that met exchange transfusion criteria).

STUDY DESIGN

Infants ≥34 weeks' gestation with severe jaundice during the first 2 weeks of life were eligible for the prospective observational study. A comprehensive auditory evaluation was performed within 72 hours of peak TSB. ANSD was defined as absent or abnormal auditory brainstem evoked response waveform morphology at 80-decibel click intensity in the presence of normal outer hair cell function. TSB, serum albumin, and unbound bilirubin were measured using the colorimetric, bromocresol green, and modified peroxidase method, respectively.

RESULTS

Five of 44 infants developed ANSD. By logistic regression, peak unbound bilirubin but not peak TSB or peak BAMR was associated with ANSD (OR, 4.6; 95% CI, 1.6-13.5; P = .002). On comparing receiver operating characteristic curves, the area under the curve for unbound bilirubin (0.92) was significantly greater (P = .04) compared with the area under the curve for TSB (0.50) or BAMR (0.62).

CONCLUSIONS

Unbound bilirubin is a more sensitive and specific predictor of ANSD than TSB or BAMR in late preterm and term infants with severe jaundice.

Saccular dysfunction in children with sensorineural hearing loss and auditory neuropathy/auditory dys-synchrony

CONCLUSION

There is a correlation between the AN/AD disorder and the saccular dysfunction in children with severe sensorineural hearing loss, which means that saccular dysfunction can be a concomitant sign of AN/AD. In conclusion, the term of audio-vestibular dys-synchrony (AVS) is a more suitable description for this condition.

OBJECTIVES

Patients with auditory neuropathy/auditory dys-synchrony (AN/AD) characteristically demonstrate poor neural responses from the vestibulocochlear nerve and brainstem while displaying evidence of intact outer hair cells function. Therefore, the objective of this study is studying of the relationship of the saccular dysfunction with AN/AD disorder in children with sensorineural hearing loss.

METHODS

In this cross-sectional study, 100 children with bilateral severe-to-profound sensorineural hearing losses underwent audiologic tests and cervical vestibular-evoked myogenic potentials (cVEMPs) at the Audiology Department of Hamadan University of Medical Sciences (Hamadan, Iran).

RESULTS

Eleven children with bilateral severe sensorineural hearing loss were given to unilateral AN/AD disorder (11 ears), and two children (4 ears) had bilateral AN/AD (total = 13 children). The ears with AN/AD took the form of unrepeatable or absent waves of ABR and presence of OAEs. The statistical analysis of an independent t-test between AN/AD ears as compared to non-AN/AD ears of these 13 children showed that the mean latencies of p13 and the mean latencies of n23 and the mean peak-to-peak amplitude had significant differences.

Performance of hearing skills in children with auditory neuropathy spectrum disorder using cochlear implant: a systematic review

Introduction

Currently, there are no doubts about the benefits of cochlear implants for the development of children with severe or profound hearing loss. However, there is still no consensus among researchers and professionals regarding the benefits for the improvement of hearing skills in children with auditory neuropathy spectrum disorder using cochlear implants.

Objective

Review the available evidence in the literature to answer the following: “What is the performance of hearing skills in children with auditory neuropathy spectrum disorder using cochlear implants?”

Methods

Systematic review of the literature through electronic database consultation, considering publications in the period 2002–2013.

Results

Twenty-two studies met the criteria and were included in the systematic review.

Conclusion

The analyzed studies demonstrated that after cochlear implant surgery, individuals with auditory neuropathy spectrum disorder improved their performance of hearing skills and had similar performance to that of children with sensorineural hearing loss using cochlear implant.

Deafness in cochlear and auditory nerve disorders

Sensorineural hearing loss is the most common type of hearing impairment worldwide. It arises as a consequence of damage to the cochlea or auditory nerve, and several structures are often affected simultaneously. There are many causes, including genetic mutations affecting the structures of the inner ear, and environmental insults such as noise, ototoxic substances, and hypoxia. The prevalence increases dramatically with age. Clinical diagnosis is most commonly accomplished by measuring detection thresholds and comparing these to normative values to determine the degree of hearing loss. In addition to causing insensitivity to weak sounds, sensorineural hearing loss has a number of adverse perceptual consequences, including loudness recruitment, poor perception of pitch and auditory space, and difficulty understanding speech, particularly in the presence of background noise. The condition is usually incurable; treatment focuses on restoring the audibility of sounds made inaudible by hearing loss using either hearing aids or cochlear implants.

[Analysis of characteristics of tinnitus in patients with auditory neuropathy spectrum disorder]

OBJECTIVE

To investigate the characteristics of tinnitus in patients with auditory neuropathy spec- trum disorder (ANSD).

METHOD

This study recruited 14 ANSD patients with tinnitus. All the ANSD patients un- derwent detailed history taking, audiological examinations and assessments of tinnitus. This study analyzed the correlation of tinnitus status and hearing loss, and discussed the effects of sex, age, and the course of disease on tinnitus in ANSD patients.

RESULT

(1) In the ANSD patients, tinnitus often occurred in 3 years after the onset of hearing loss; (2) Tinnitus was highly prevalent in ANSD patients, and the severity of tinnitus was mostly from mild to moderate; (3) There was no obvious correlation between the subjective grading of tinnitus and hearing loss de- gree, and the impact of curve patterns of hearing loss on the level of tinnitus need much more evidence-based proof; (4) Along with the course extension, the impact of tinnitus on the quality of life was much more obvious; (5) Some risk factors such as noise exposure could be the reasons of aggravating the degree of tinnitus.

CONCLUSION

Tinnitus in ANSD patients has its unique clinical features. The study of Tinnitus in ANSD patients can provide clinical basis for further research in ANSD.

Clinical features of rapidly progressive bilateral sensorineural hearing loss

CONCLUSION

Rapidly progressive bilateral sensorineural hearing loss (SNHL) often develops as a symptom of intracranial diseases or systemic vasculitis. For early diagnosis and treatment of these potentially fatal diseases, a history of hearing deterioration within 2 months and associated symptoms may be important.

OBJECTIVES

To reveal clinical features and causative diseases for rapidly progressive bilateral SNHL.

METHODS

The inclusion criterion was patients with bilateral progressive SNHL, who had experienced difficulty in daily conversation within 4 days to 1 year after the onset of hearing loss awareness. This study was a retrospective evaluation of 12 patients with rapidly progressive bilateral SNHL who visited our hospital between 2007 and 2011.

RESULTS

The causative disease for hearing loss was identified in 11 of 12 patients; intracranial lesions including nonbacterial meningitis, meningeal metastasis of lymphoma, and superficial siderosis in 4 patients, systemic vasculitis in 2, auditory neuropathy spectrum disorder in 1, and an isolated inner ear disorder in 4. Relatively rapid hearing deterioration within 2 months showed a significant association in six patients with an intracranial lesion or systemic vasculitis. Moreover, all these six patients complained of dizziness and/or non-cochleovestibular symptoms such as fever, headache, and/or altered mental state in addition to hearing loss.

Cortical Motion Deafness

The extent to which the auditory system, like the visual system, processes spatial stimulus characteristics such as location and motion in separate specialized neuronal modules or in one homogeneously distributed network is unresolved. Here we present a patient with a selective deficit for the perception and discrimination of auditory motion following resection of the right anterior temporal lobe and the right posterior superior temporal gyrus (STG). Analysis of stimulus identity and location within the auditory scene remained intact. In addition, intracranial auditory evoked potentials, recorded preoperatively, revealed motion-specific responses selectively over the resected right posterior STG, and electrical cortical stimulation of this region was experienced by the patient as incoming moving sounds. Collectively, these data present a patient with cortical motion deafness, providing evidence that cortical processing of auditory motion is performed in a specialized module within the posterior STG.

[Inferior vestibular nerve impairment in auditory neuropathy]

OBJECTIVE

To investigate if auditory neuropathy have inferior vestibular nerve (IVN) lesion and to explore the relation between AN and the IVN lesion by vestibular evoked myogenic potentials (VEMPs).

METHODS

VEMPs were observed in 13 patients with auditory neuropathy. And the relation among the duration, hearing threshold of lower frequency and speech discrimination score with VEMPs were observed.

RESULTS

Fifty-four percent patients in auditory neuropathy had abnormal VEMPs. They took the form of lower amplitude and no response. The statistical analysis showed that the abnormality of VEMPs had no correlation with lower frequency hearing loss, the duration and speech discrimination score.

CONCLUSIONS

The IVN dysfunction may coexist with auditory neuropathy, having lesion in the IVN. However, there was no significant relation between the severity of AN and VEMPs, which meant that AN and inferior vestibular neuropathy had their independence to some extent.

First auditory brainstem implant in the Czech Republic

In the Czech Republic, the first implantation of a stimulation electrode into the brainstem was performed on 11 January 1999 in the Department of ORL, Head and Neck Surgery, The First Medical Faculty, Charles University in Prague, University Hospital Motol. The selected patient was a 40-year-old woman with neurofibromatosis type 2 (NF2) who had previously undergone bilateral vestibular schwannoma surgery. Both tumours had been radically removed, the left-sided tumour in 1987, the right-sided one in 1988. She had been completely deaf since the last operation, i.e., for 11 years. The surgery was realized by the international cooperation of three teams. Placement of the electrode pad of the Nucleus CI21 + 1M system on the ventral and dorsal cochlear nuclei was performed. Electrically evoked auditory brainstem responses (EABRs) proved the correct position of the electrode array. The post-operative course was uneventful. Six weeks after the surgery the patient received her speech processor. Since that time, the patient already absolved several sessions of a speech processor tune-up. She uses the device as an aid in lip-reading. No adverse or pathological side effects have been observed. The patient was the 45th person in Europe to receive an ABI and the first in the Czech Republic.

Multichannel auditory brainstem implant: US clinical trial results

Since 1994, a US Food and Drug Administration clinical trial evaluated the multichannel auditory brainstem implant (ABI) on 92 subjects with neurofibromatosis type 2 (NF2). The trial has shown that 85 per cent of patients receive auditory sensations. A small number of patients demonstrate a clinically significant degree of open-set sentence recognition in the sound-alone condition; however, when the ABI is combined with lip-reading cues, 93 per cent of patients demonstrate improved sentence understanding at three to six months. In addition, the majority of recipients report daily use of their devices, and satisfaction with the decision to receive the ABI.

Multichannel auditory brainstem implantation: the Australian experience

The multichannel auditory brainstem implant (ABI) provides the potential for hearing restoration in patients with neurofibromatosis type 2 (NF2). Programmes for auditory brainstem implantation have been established in two Australian centres. Eight patients have been implanted under the protocol of an international multi-centre clinical trial. Three patients had ABI insertion at the time of first side tumour removal, four at second side tumour removal and one after previous bilateral surgery where there was some residual tumour. The translabyrinthine approach was used in all cases. Successful positioning of the electrode array was achieved in seven of eight patients, all of whom achieved auditory perception with electrical stimulation. Intra-operative electrically evoked auditory brainstem response testing was successful in four patients and was useful in confirming correct electrode position. In six cases post-operative psychophysical and auditory perception testing demonstrated that useful auditory sensations were achieved. Five of these patients regularly used the implant. In one patient electrode placement was unsuccessful and only non-auditory sensations occurred on stimulation. In the remaining patients non-auditory sensations were minimal and avoidable by selective electrode programming. Auditory brainstem implantation should be considered in patients with NF2. The greatest benefit is seen in patients without debilitating disease who have non-aidable hearing in the contralateral ear.

First auditory brainstem implantation in Poland: auditory perception results over 12 months

Auditory brainstem implants (ABIs) are a modern method of treatment of total bilateral deafness in cases of extracochlear origin. In most cases therapy is applied in patients with neurofibromatosis type 2 (NF2). This paper presents the results of surgical treatment and rehabilitation in a 28-year-old woman with bilateral, multiple tumours of the central nervous system causing total deafness. Simultaneous removal of the tumours and implantation of ABI allowed treatment of the potentially lethal pathology and hearing restoration. Improving auditory skills and excellent tests results were noted in the year following implantation.

Central auditory processing disorder in school-aged children: a critical review

The rationale to evaluate for central auditory processing disorder (CAPD) in school-aged children is based on the assumption that an auditory-specific perceptual deficit underlies many learning problems including specific reading and language disabilities. A fundamental issue in this area is whether convincing empirical evidence exists to validate this proposition. Herein, we consider the issue of modality specificity by examining the extent to which reading, language, and attention disorders in school-aged children involve perceptual dysfunctions limited to a single sensory modality. Difficulty in validating CAPD as a diagnostic label is due in large part to use of the unimodal inclusive framework, which has biased the diagnosis to favor sensitivity of test results over documenting the specificity of the deficit. Indeed, empirical research documenting modality-specific auditory-perceptual dysfunction in this population is scarce. Therefore, the existing literature on this topic has not clarified the "true" nature of the problem, and has left many questions about this disorder unanswered. It is argued that demonstrating modality specificity is one way to rule out supramodal disorders as explanations for observed dysfunction. Multimodal perceptual testing is one logical approach to help clarify this area of investigation.

Central auditory dysfunction, cognitive dysfunction, and dementia in older people

OBJECTIVES

To determine in older people the relation between auditory dysfunction and cognitive dysfunction, and if central auditory test abnormalities predict the onset of clinical dementia or cognitive decline.

DESIGN

Prospective population-based cohort study.

SETTING

Framingham Heart Study outpatient biennial examinations 18 and 21.

PARTICIPANTS

Members of the Framingham Heart Study cohort with normal findings from cognitive screening tests at biennial examination 18.

MEASUREMENTS

Peripheral audiometric thresholds and word recognition in quiet; Synthetic Sentence Identification with Ipsilateral Competing Message (SSI-ICM); Mini-Mental State Examination; and detailed neuropsychological testing of subjects with abnormal findings from the Mini-Mental State Examination. Relative risk of dementia was determined using age-adjusted Cox proportional hazards regression models.

RESULTS

Hearing loss significantly lowered performance on the verbal parts of the Mini-Mental State Examination. The relative risk of subsequent clinical dementia or cognitive decline was 6 in subjects with very poor scores (< 50%) in one ear on the SSI-ICM (P = .02); the relative risk was 12.5 if the poor scores were present in both ears (P = .001).

CONCLUSIONS

Central auditory dysfunction precedes senile dementia in a significant number of cases and may be an early marker for senile dementia. Hearing tests should be included in the evaluation of persons older than 60 years and in those suspected of having cognitive dysfunction.

Bilateral auditory acuity of schizophrenic patients: effects of repeated testing, time of day and medication

Higher than normal auditory thresholds were demonstrated in chronic schizophrenic patients. A greater right ear sensitivity than left was exhibited, although right ear superiority diminished with repeated testing over weeks while left ear thresholds remained relatively stable. The results of acoustic impedance measures suggest that these findings are not associated with peripheral outer and middle ear disorders.

Audiologic findings in Charcot-Marie-Tooth disease

An audiologic study of a 54-year-old patient with Charcot-Marie-Tooth disease whose initial symptom was hearing difficulty is presented. While findings from basic audiologic tests were not consistent with the degree of auditory difficulty reported by the patient, special testing did indicate a notable deficit. Although the auditory periphery was probably mildly involved, it seemed that the major auditory deficit was central.

[Diallinas-amalric syndrome (author's transl)]

Diallinas-Amalric syndrome is characterized by a combination of central pseudoretinopathia pigmentosa and pancochlear hearing loss. The dystrophy of the macula may occur in patients in whom hearing was unpaired in the prenatal, perinatal and/or postnatal periods. This fact indicates that Diallinas-Amalric syndrome must be seen as a nonspecific manifestation of a bisensorial impairment of very varied etiology.

Hearing loss in brainstem disorders

A retrospective study of 309 unselected patients with brainstem disorders was carried out to establish the incidence and degree of hearing loss in this group as a whole and in each of three separate pathologies: multiple sclerosis, vertebro-basilar ischaemia and brainstem tumours. Pure tone audiograms were corrected for age and sex and upon analysis, thereafter, 59% and 26% of patients were found to have hearing thresholds in excess of 10dB and 30dB respectively. The hearing loss tended to be slight to moderate, 87% of those with a deficit were in the range 11--59dB, and tended to involve the higher frequencies. No characteristic audiometric configuration emerged. 75% of those with a hearing loss suffered a bilateral deficit. Considering the multiple sclerosis, vertebro-basilar insufficiency and tumour groups individually, similar findings were observed with the mildest losses occurring in multiple sclerosis and the most severe in the tumour group.

Central auditory function in stutterers

Central auditory function was assessed in 10 stutterers and 10 nonstutterers. Performance of the two groups was compared for seven audiometric procedures including acoustic reflex threshold, acoustic reflex amplitude function, performance intensity function for monosyllabic phonetically balanced (PB) words, performance intensity function for Synthetic Sentence Identification, Synthetic Sentence Identification with Ipsilateral Competing Message, Synthetic Sentence Identification with Contralateral Competing Message, and the Staggered Spondaic Word test. Relative to the control group, the performance of the stuttering group was depressed on three procedures--the acoustic reflex amplitude function, Synthetic Identification with Ipsilateral Competing Message, and Staggered Spondaic Word test. As a group, the stutterers presented evidence of a central auditory deficiency. The pattern of test results suggests a disorder at the brainstem level. The subtlety of the deficiency is emphasized.