Article
Streamline fitting of speech processors using automatically recorded ECAPs
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Published: | May 31, 2005 |
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Outline
Text
Introduction
Different fitting methods to create speech processor maps are investigated as part of a multi-centric study to evaluate the Nucleus system 4.
Materials and Methods
In clinical practice, adult CI recipients are fitted with maps at stimulation levels based on psycho-acoustical measurements. For toddlers, stimulation thresholds (T-) and comfortable stimulation levels (C-levels) have to be estimated by the use of objective methods like Neural Response Telemetry (NRT) and electrically evoked stapedial reflex threshold measurements.
Results
System 4 assists the partly automated creation of maps. It is possible to record the ECAP thresholds automatically with NRT (T-NRT). Only these T-NRT and a pair of T/C-level of a single electrode are needed to generate a map, a so called streamline map. The intra- and post-operative T-NRTs of 25 post-lingually deafened adults with less than 15 years of deafness are estimated automatically as well as manually for five electrodes and compared to each other. The T-NRT based streamline maps are compared with psycho-acoustically fitted maps for a subset of the recipients in terms of the Freiburg monosyllable speech-intelligibility tests.
Conclusions
Although the T/C-levels of some electrodes differ significantly between the streamline and the behavioural maps, the test scores are mainly indistinguishable intra-individually. The recipient's preference for one of these maps depends on the recipient and may change with time.