Effects of stimulus repetition rate on electrically evoked auditory brainstem potentials in postlingually deafened adult cochlear implant recipients
- Conditions
- H90H91Conductive and sensorineural hearing lossOther hearing loss
- Registration Number
- DRKS00026195
- Lead Sponsor
- niversitätsklinikum Greifswald
- Brief Summary
Background: By using outcome prediction scores, it is possible to distinguish between good and poor performers with cochlear implants (CI) after CI implantation. The reasons for poor performance, despite good basic conditions, can be manifold. On the one hand, the postoperative fitting may be inadequate; on the other, neurophysiological disease processes may impair speech understanding with a CI. These disease processes are not yet fully understood. In acoustics, it is known that the auditory brainstem responses (ABR) and their latencies and amplitudes allow differential diagnosis based on reference values for normal-hearing individuals. The aim of this study was to provide reference values for electrically evoked brainstem responses (EABRs) in terms of rate-dependent latencies and amplitudes. Methods: 20 ears of 18 experienced adult CI recipients with a predicted and measured good postoperative word recognition score were recruited from the clinic’s patient pool. In the same stimulation mode and intensity we measured latencies and interpeak-latencies of EABRs and electrically evoked compound action potentials (ECAPs). With a defined supra-threshold stimulation intensity above the individual ECAP threshold, we applied stimulation at several rates between 11 and 91 stimuli per second. Results: We found rate dependences for EABR latency t3 and t5 in the order of 0.19 ms and 0.37 ms, respectively, while ECAP was not affected by rate. Correspondingly, the interpeak intervals’ rate dependences for t5-t1, t5-t3 and t3-t1 were of the order of 0.37 ms, 0.18 ms and 0.19 ms. Comparing the EABR amplitudes between the stimulation rates 11/s and 81/s, we found that at 81/s the amplitudes were significantly reduced down: to 73% for A3 and 81% for A5. These rate dependences of latency and amplitude in EABR have characteristics comparable to those of acoustic ABR. Conclusions: These data may serve to provide reference values for EABR and ECAP latencies, interpeak intervals and amplitudes with respect to stimulation rate. Altered response patterns of ECAPs and EABRs to normalised stimulation modes could be used in the future to describe and classify neuropathological processes in a better-differentiated way.
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- Complete
- Sex
- All
- Target Recruitment
- 20
Patient consent
- Age: = 18 years
- Gender: female, male, divers
- Side: left, right
- Implants: CI24RE, CI5xx, CI6xx
- Electrodes: Slim Straight, Contour Advance®, Slim Modiolar
- Depending on preoperative grouping (according to Hoppe [4]), monosyllabic speech perception score in upper three quartiles - Implant in specification, at least six months CI-experience
- Known mental handicap
- Known central hearing disorders
- Short cut or open circuit of electrode 11 or 18.
Study & Design
- Study Type
- interventional
- Study Design
- Not specified
- Primary Outcome Measures
Name Time Method Reference values of the EAEP rate dependencies (absolute and relative shift in latency, changes in amplitude and changes in potential morphology) in CI patients who have achieved the expected care outcome.
- Secondary Outcome Measures
Name Time Method Criteria for the differential diagnosis of retrocochlear or neuronal hearing disorders in the context of CI care.