Artikel
Advanced telemetry capabilities of the PULSARci100 cochlear implant
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Autoren
Veröffentlicht: | 31. Mai 2005 |
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Gliederung
Text
Introduction
The level of speech intelligibility that can be reached with cochlear implants depends, among other parameters, on patient specific speech processor settings. Thresholds and maximum stimulation levels have to be found. To simplify the fitting procedure as well as for research purposes and to prove the correct functioning of the implant under special circumstances the use of objective measures might be helpful.
Materials and Methods
Besides the Impedance and Field Telemetry (IFT) known from the COMBI 40+ system, the precision IFT of the PULSARci100 provides four different gains for even more accurate information. In addition to that the Auditory Nerve Response Telemetry (ART) offers the possibility of recording the Electrically Evoked Compound Action Potential (ECAP) of the auditory nerve. Both functionalities are based on ΣΔ modulation at 1.2 MHz, for the digitalization of the signal.
Results
An internal RAM with short readout time allows the storage of the digitized signal within a time window of about 1.7ms. In the ECAP-recording mode this measurement window can be moved to any position of interest. For the amplification of the very small ECAP-signals ART uses an optimized single state blanking amplifier with a fixed gain of 100. Also the ΣΔ- modulator offers an additional signal amplification.
Conclusions
Besides the use of various test signal for an objective evaluation first experiences with the telemetry capabilities of the PULSARci100 have been gathered in real test situation at patients.