Article
Electrically evoked cortical auditory potentials in Cochlear Implant listeners in comparison to speech performances
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Published: | July 6, 2010 |
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Outline
Text
Cortical auditory evoked potentials (CAEPs) in Cochlear Implant (CI) listeners reflect the activity of auditory cortex and are able to objectify the results of cochlear implantation. They can be evoked by the stimulation of particular implant electrodes by using experimentally developed software and observed both in response to the beginning of the stimulation (P1N1P2 complex) and to change during the stimulation (Acoustic Change Complex, ACC). The aim of our study was to measure CAEPs in CI listeners during the first hearing rehabilitation (FHR) and after 6 months of CI usage and to compare CAEPs with individual speech performances.
CAEPs were measured in 10 CI listeners (age 59±19 years, 3 females, 7 males) during the first 5 days after speech processor switch on and after 6 months of CI experience. The speech performance was measured by a monosyllabic words test. The CAEPs were obtained using direct electrical stimulation of neighbouring implant electrodes: basal electrodes nos.3/4, middle electrodes nos.10/11 and apical electrodes nos.18/19. The stimulation level based on subjective sensation of “loud, but not too loud” signals and was adjusted until the sensation of both electrodes was the same.
The latencies of P1N1P2 complex tend to decrease, the N1P2 amplitudes of P1N1P2 complex and of ACC tend to increase during the FHR. The parameters of P1N1P2 complex do not correlate significantly with speech performance. The latencies and the N1P2 amplitude of ACC correlate significantly with speech performance, but only during the FHR.
By means of the ACC the changes of central hearing system can be ascertained, which are responsible for speech performance improvement during the FHR.
References
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