Prevalencia de la neuropatía auditiva: estudio prospectivo en un hospital de tercer nivel

ATP1A3 mutations can cause progressive auditory neuropathy: a new gene of auditory synaptopathy

The etiologies and prevalence of sporadic, postlingual-onset, progressive auditory neuropathy spectrum disorder (ANSD) have rarely been documented. Thus, we aimed to evaluate the prevalence and molecular etiologies of these cases. Three out of 106 sporadic progressive hearing losses turned out to manifest ANSD. Through whole exome sequencing and subsequent bioinformatics analysis, two out of the three were found to share a de novo variant, p.E818K of ATP1A3, which had been reported to cause exclusively CAPOS (cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural hearing loss) syndrome. However, hearing loss induced by CAPOS has never been characterized to date. Interestingly, the first proband did not manifest any features of CAPOS, except subclinical areflexia; however, the phenotypes of second proband was compatible with that of CAPOS, making this the first reported CAPOS allele in Koreans. This ANSD phenotype was compatible with known expression of ATP1A3 mainly in the synapse between afferent nerve and inner hair cells. Based on this, cochlear implantation (CI) was performed in the first proband, leading to remarkable benefits. Collectively, the de novo ATP1A3 variant can cause postlingual-onset auditory synaptopathy, making this gene a significant contributor to sporadic progressive ANSD and a biomarker ensuring favorable short-term CI outcomes.

Prevalence and Audiological Characteristics of Auditory Neuropathy Spectrum Disorder in Pediatric Population: A Retrospective Study

Auditory neuropathy spectrum disorder (ANSD) is a type of hearing disorder which is challenging for assessment and rehabilitation. This disorder has been studied over a decade and prevalence of the disorder is variable. The study aimed at estimating the prevalence and audiological characteristics of ANSD in children. A retrospective study was conducted from the medical records of pediatric patients evaluated at Rajiv Gandhi Government General Hospital and Madras Medical College, Chennai to estimate the prevalence of ANSD. Medical records of 2,624 children evaluated during the period of November 2010 to October 2012 within the age range of 6 months to 12 years were analyzed. Out of 2,624 pediatric population assessed 217 (8.26 %) of them had unilateral or bilateral sensory neural hearing loss with varying degrees. Out of 217 children with sensory neural hearing loss 5.06 % (N = 11) had ANSD. Audiological characteristics varied among the group. Children with ANSD had varied degree of hearing thresholds from normal to profound hearing impairment. All of them had 'A' type tympanogram with absent stapedial reflexes. DPOAEs or TEOAEs were observed in 54 % of population with ANSD. All of them had abnormal auditory brainstem responses (ABR). Replicable cochlear microphonics was observed in 46 % of children with ANSD. These results indicate that ANSD is not a rare condition among children and we emphasize the use of objective tests like tympanometry, Stapedial Reflex test, otoacoustic emissions and ABR in routine hearing assessment procedure for all children to identify ANSD.