Paul J. Abbas|Viral D. Tejani|Rachel A. Scheperle|Carolyn J. Brown
Using Neural Response Telemetry to Monitor Physiological Responses to Acoustic Stimulation in Hybrid Cochlear Implant Users
Montclair State University|University of Iowa Hospitals and Clinics|Montclair State University|University of Iowa Hospitals and Clinics|Montclair State University|Montclair State University|University of Iowa Hospitals and Clinics
objective report describes results series experiments use neural response telemetry nrt system nucleus cochlear implant ci measure response peripheral auditory system acoustic stimulation nucleus hybrid ci users objectives study determine whether could separate responses hair cells neurons evaluate stability measures time design fortyfour ci users participated residual acoustic hearing used nucleus hybrid s8 s12 l24 ci standard lateral wall ci422 implant nrt system ci used trigger acoustic stimulus 500hz tone burst click presented low stimulation rate 10 15 50 per second implanted ear via insert earphone record cochlear microphonic auditory nerve neurophonic compound action potential cap apical intracochlear electrode record acoustically evoked responses longer time window available commercial nrt software required limitation circumvented making multiple recordings stimulus using different time delays onset stimulation onset averaging recordings concatenated offline matched recordings elicited using positive negative polarity stimuli added offline emphasize neural potentials sum subtracted offline emphasize potentials primarily generated cochlear hair cells dif assumptions regarding origin sum dif components tested comparing magnitude derived responses recorded using various stimulation rates magnitudes sum dif components compared behavioral thresholds results sum dif components identified subjects consistent hair cell neural responses acoustic stimulation subset study participants dif components grew stimulus level increased little sum components identified latency caps response click stimuli long relative reports literature recordings obtained using extracochlear electrodes difference response latency general morphology caps recorded likely due differences across subjects hearing loss configuration use high stimulation rates tended decrease sum cap components dif components suggest effect reflects neural adaptation individuals repeated measures made intervals long 9 months changes time dif sum cap thresholds mirrored changes audiometric threshold subjects experienced loss acoustic hearing implanted ear conclusions nucleus nrt software used record peripheral responses acoustic stimulation threshold suprathreshold levels providing window status auditory hair cells primary afferent nerve fibers acoustically evoked responses sensitive changes hearing status consequently could useful characterizing specific pathophysiology hearing loss experienced population ci users