Audibility, Speech perception and processing of temporal cues in ribbon synaptic disorders due to OTOF mutations.

Audibility, Speech perception and processing of temporal cues in ribbon synaptic disorders due to OTOF mutations. Hear Res. 2015 Jul 15; Authors: Santarelli R, Del Castillo I, Cama E, Scimemi P, Starr A Abstract Mutations in the OTOF gene encoding otoferlin result in a disrupted function of the ribbon synapses with an impaired multivesicular glutamate release. Most affected subjects present with congenital hearing loss and abnormal auditory brainstem potentials associated with preserved cochlear hair cell activities (otoacoustic emissions, cochlear microphonics [CMs]). Transtympanic electrocochleography (ECochG) has recently been proposed for defining the details of potentials arising in both the cochlea and auditory nerve in this disorder, and with a view to shedding light on the pathophysiological mechanisms underlying auditory dysfunction. We review the audiological and electrophysiological findings in children with congenital profound deafness carrying two mutant alleles of the OTOF gene. We show that cochlear microphonic (CM) amplitude, summating potential (SP) amplitude and latency are normal, consistently with a preserved outer and inner hair cell function. In the majority of OTOF children, the SP component is followed by a markedly prolonged low-amplitude negative potential by comparison with the compound action potential (CAP) recorded in normally-hearing children. This potential is identified at intensities as low as 90 dB ...
Source: Hearing Research - Category: Audiology Authors: Tags: Hear Res Source Type: research