Artikel
Processing of artifact in electrically evoked action potentials
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Autoren
Veröffentlicht: | 31. Mai 2005 |
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Gliederung
Text
Introduction
Electrically evoked compound action potentials (ECAP) are strongly affected by stimulation artifact. In this study we analyze and compare different methods to process the stimulation artifact affecting the electrically evoked compound action potentials.
Materials and Methods
The methods for artifact processing considered are based on (1) the use of masked responses to subtract the artifact to the contaminated response; (2) the use of a tri-phase stimulus in order to control the transitory to the electrical perturbation in the vicinity of the stimulation electrode; and (3) the application of numerical methods to compensate for the stimulation artifact. In this analysis we include ECAP recordings from 5 patients implanted with a MED-EL Pulsar device. The responses were recorded by means of the auditory response telemetry incorporated in this cochlear implant.
Results
Even though the masking method sometimes provides appropriate cancellation of the artifact, since the artifact for a couple of stimuli is different to that for a single stimulus, sometimes the artifact is not appropriately cancelled and a false ECAP response appears. The use of tri-phase stimulus provides a more appropriate cancellation of the artifact because the electrical perturbation after the stimulation can be reduced with an appropriate configuration of this stimulus. This procedure does not produce false ECAP responses. Numerical methods must be carefully applied because the selection of an improper function to fit the response results in false ECAPs.
Conclusions
Tri-phase stimuli is a promising method for artifact cancellation in electrically evoked compound action potentials.