ABSTRACT
BACKGROUND: Incomplete partition type III (IP III) is defined by a missing lamina cribrosa between the cochlea and the internal auditory canal (IAC). Cochlear implantation (CI) may result in an insertion of the electrode array into the IAC. The aim of this study is to evaluate CI surgery protocols, long-term audiological outcome, mapping and electrophysiological data after CI in IP III patients. MATERIALS AND METHODS: Nine IP III patients were implanted with perimodiolar electrode arrays between 1999 and 2014; eight of them were included in this study. We evaluated mapping data, stapedius reflexes, electrode impedances and ECAP thresholds. We matched them with 3 CI patients each with normal cochlear morphology regarding sex, age, side, implant type and surgical date. Speech discrimination was evaluated with the Oldenburger sentence test for adults, Göttingen audiometric speech test for children and the Freiburger monosyllabic word test. RESULTS: 3 years after CI IP III patients showed a significant increase in pulse width, calculated electric load and electrode impedances in basal electrodes. Intraoperative electrically-evoked stapedius reflexes could be measured in all patients. Speech recognition scores were lower than average scores for matched patients, but without statistical significance. CONCLUSIONS: The significant increase of pulse width, electric load and electrode impedances of basal electrodes over time seem to be characteristic for IP III patients probably occurring due to fibrosis and neurodegeneration of the cochlear nerve. The long term audiological results are stable. Intraoperative imaging and stapedius reflexes are highly recommended to control the right position of the electrode array.
Subject(s)
Cochlea , Cochlear Implantation , Cochlear Implants , Adult , Child , Cochlea/pathology , Cochlea/physiopathology , Cochlear Nerve , Humans , Reflex, AcousticABSTRACT
BACKGROUND: Dichotic speech recognition of side-separated speech stimuli requires their central nervous processing and has been used since the 1950s in a variety of clinical settings. OBJECTIVE: The objective of this study was to investigate the dichotic speech recognition of normal-hearing (NH) subjects, cochlear implant (CI) recipients with single-sided deafness (SSD), and bilateral CI (BilCI) recipients with the dichotic discrimination test according to Feldmann. MATERIALS AND METHODS: The speech recognition of ten adult NH subjects, ten SSD CI recipients, and ten BilCI recipients was determined at 65â¯dB SPL or 65â¯dB SPL equivalent for monotic presentation of trisyllabic nouns of the Feldmann test (NH subjects: better ear, poorer ear; SSD CI recipients: NH ear, CI; BilCI recipients: better CI, poorer CI) and for dichotic, i.e., simultaneous side-separated, presentation. RESULTS: The NH subjects showed significantly poorer speech recognition for dichotic presentation than for monotic presentation. Speech recognition of SSD CI recipients was significantly worse with the CI than with the NH ear for both monotic and dichotic presentation. For both presentation conditions, BilCI recipients obtained significantly lower speech recognition with the poorer CI compared to the better CI. With each of the two CI, BilCI recipients had significantly worse speech recognition for dichotic presentation than for monotic presentation. CONCLUSION: All three study groups-NH subjects, SSD CI recipients, and BilCI recipients-were able to recognize dichotically presented speech with both ears. For SSD CI recipients, there was no negative effect of the CI on speech recognition with the NH ear for dichotic presentation.
Subject(s)
Cochlear Implants , Deafness , Speech Perception , Adult , Cochlear Implantation , Humans , SpeechABSTRACT
BACKGROUND: Incomplete partition type III (IP III) is defined by a missing lamina cribrosa between the cochlea and the internal auditory canal (IAC). Cochlear implantation (CI) may result in an insertion of the electrode array into the IAC. The aim of this study is to evaluate CI surgery protocols, long-term audiological outcome, mapping and electrophysiological data after CI in IP III patients. MATERIALS AND METHODS: Nine IP III patients were implanted with perimodiolar electrode arrays between 1999 and 2014; eight of them were included in this study. We evaluated mapping data, stapedius reflexes, electrode impedances and ECAP thresholds. We matched them with 3 CI patients each with normal cochlear morphology regarding sex, age, side, implant type and surgical date. Speech discrimination was evaluated with the Oldenburger sentence test for adults, Göttingen audiometric speech test for children and the Freiburger monosyllabic word test. RESULTS: 3 years after CI IP III patients showed a significant increase in pulse width, calculated electric load and electrode impedances in basal electrodes. Intraoperative electrically-evoked stapedius reflexes could be measured in all patients. Speech recognition scores were lower than average scores for matched patients, but without statistical significance. CONCLUSIONS: The significant increase of pulse width, electric load and electrode impedances of basal electrodes over time seem to be characteristic for IP III patients probably occurring due to fibrosis and neurodegeneration of the cochlear nerve. The long term audiological results are stable. Intraoperative imaging and stapedius reflexes are highly recommended to control the right position of the electrode array.
