![]() ![]() The latter clearly improves after cochlear implantation (CI) (( b), black line). Aided tonal and speech perception outcomes with acoustical hearing aids remain poor and comparable to unaided perception. Unaided free field speech discrimination is poor (( b), 10% gray dot at 80 dB). ![]() Unaided pure-tone audiometry (( a), both ears) shows bilateral hearing loss mainly for low frequencies. Auditory steady-state responses (ASSRs) thresholds ( e) are present in the left (X) more than in the right (O) ear.Īudiological assessment in a subject with Brown–Vialetto–Van Laere syndrome-related auditory neuropathy spectrum disorder (ANSD), resulting in neural impairment of the 8th and 12th cranial nerves and the optic nerves. abnormal auditory brainstem responses (ABRs) ( d) show the responses evoked by clicks presented in rarefaction (R) and condensation (C) phase and the subtraction of R and C (R − C), highlighting the cochlear microphonic (CM) and the lack of waves V in the summation (R + C). Speech perception was poor in unaided condition (( c), 10% gray dot at 60dB), it was partially improved by acoustical hearing aids (( c), gray line) but became significantly better with cochlear implant (( c), black line). The tonal hearing thresholds remain poor in the right ear aided by an acoustical hearing aid (( b), gray line) but are clearly improved in the left ear by cochlear implant (( b), black line). Unaided pure tonal thresholds in both ears are shown in ( a). CAPOS is an acronym for Cerebellar ataxia, Areflexia, Pes cavus, Optic atrophy and Sensorineural hearing loss. Hearing aids are indicated in the treatment of ANSD with mild to moderate hearing loss, whereas cochlear implantation is the first choice of treatment in case of profound hearing loss, especially in case of IHC presynaptic disorders, or in case of poor auditory outcomes with conventional hearing aids.ĪNSD auditory neuropathy spectrum disorder auditory synaptopathy cochlear implant genetics hidden hearing loss.Īudiological assessment in 8-year-old patient with CAPOS syndrome. Besides OAEs and ABRs, audiological assessment includes stapedial reflex measurements, supraliminal psychoacoustic tests, electrocochleography (ECochG), auditory steady-state responses (ASSRs) and cortical auditory evoked potentials (CAEPs). The study of genetics and of the implicated sites of lesion correlated with clinical findings have also led to a better understanding of the molecular mechanisms underlying the various forms of ANSD, and may guide clinicians in better screening, assessment and treatment of ANSD patients. A wide range of prenatal and postnatal etiologies have been proposed. The exact prevalence of ANSD remains unknown clinical findings show a large variability among subjects with hearing impairment ranging from mild to profound hearing loss. These electrophysiological characteristics have led to the hypothesis that ANSD may be caused by various dysfunctions at the cochlear inner hair cell (IHC) and spiral ganglion neuron (SGN) levels, while the activity of outer hair cells (OHCs) is preserved, resulting in discrepancies between pure-tone and speech comprehension thresholds. Affected individuals usually present with abnormal auditory brainstem responses (ABRs), but normal otoacoustic emissions (OAEs). Auditory neuropathy spectrum disorder (ANSD) refers to a range of hearing impairments characterized by deteriorated speech perception, despite relatively preserved pure-tone detection thresholds. ![]()
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