OPA1-related auditory neuropathy: site of lesion and outcome of cochlear implantation.
Bottom Line: Hearing impairment is the second most prevalent clinical feature after optic atrophy in dominant optic atrophy associated with mutations in the OPA1 gene.In this study we characterized the hearing dysfunction in OPA1-linked disorders and provided effective rehabilitative options to improve speech perception.The use of cochlear implant improved speech perception in all but one patient.
Affiliation: 1 Department of Neurosciences, University of Padova, Via Giustiniani 2, 35128 Padova, Italy 2 Audiology and Phoniatrics Service, Treviso Regional Hospital, Piazza Ospedale 1, 31100 Treviso, Italy email@example.com.Show MeSH
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Mentions: To clarify whether the prolonged potentials originate from neural or from receptor activation, we used an adaptation procedure that preferentially attenuates neural responses with minor changes in summating potential amplitude (Eggermont and Odenthal, 1974; Santarelli et al., 2008). Figure 5 shows the recordings obtained at 100 dB SPL from one control subject with normal hearing and two representative OPA1-M patients in response to the click stimulation sequence reported at the bottom of the graph. Mean values of normalized amplitudes are reported in the right panel as a function of click position in the stimulus sequence for both controls with normal hearing and OPA1-M patients, superimposed on mean normalized summating potential amplitudes calculated for controls. In the normal controls, compound action potential amplitude was markedly attenuated after adaptation (61%), whereas summating potential attenuation was much lower (17%). Moreover, response duration as measured from summating potential onset to return to baseline was almost unchanged after adaptation. In OPA1-M patients, the prolonged response was markedly attenuated after adaptation, and the amount of peak amplitude attenuation was comparable with that of the normal compound action potential (52%). Moreover, a high stimulation rate reduced the duration of the response evoked by the last click in the stimulus sequence (range 2.1–3.5 ms) to the values seen in controls (range 1.9–3.4 ms) (Santarelli et al., 2008). These findings point to a neural rather than a receptor origin for the generation of the prolonged negative potentials recorded from OPA1-M patients.Figure 5
Affiliation: 1 Department of Neurosciences, University of Padova, Via Giustiniani 2, 35128 Padova, Italy 2 Audiology and Phoniatrics Service, Treviso Regional Hospital, Piazza Ospedale 1, 31100 Treviso, Italy firstname.lastname@example.org.