%0 Journal Article
%T In-vitro characterization of a cochlear implant system for recording of evoked compound action potentials
%A Christian Neustetter
%A Matthias Zangerl
%A Philipp Spitzer
%A Clemens Zierhofer
%J BioMedical Engineering OnLine
%D 2012
%I BioMed Central
%R 10.1186/1475-925x-11-22
%X In-vitro setup: The cochlear implant, including all attached electrodes, was fixed in a tank of physiologic saline solution. Sinusoidal signals of the same frequency but with different amplitudes were delivered via a signal generator for measuring and recording on a single electrode.Computer simulations: A basic mathematical model including the main elements of the recording system, i.e. amplification and digitalization stage, was developed. For this, digital output for sinusoidal input signals of different amplitudes were calculated using in-vitro recordings as reference.Using an averaging of 100 measurements the recording system behaved linearly down to approximately -60 dB of the input signal range. Using the same method, a system resolution of 10 ¦ÌV was determined for sinusoidal signals. The simulation results were in very good agreement with the results obtained from in-vitro experiments.The recording system implemented in the MED-EL PULSARCI100 cochlear implant for measuring the evoked compound action potential of the auditory nerve operates reliably. The developed mathematical model provides a good approximation of the recording system.Cochlear implants (CIs) are prostheses that aim to facilitate auditory perception and speech understanding in patients suffering from profound hearing loss. In normal hearing persons, hair cells inside the cochlea transform acoustic signals into complex patterns of neural signals. These are then transported along the auditory nerve to the brain where they are perceived as sound. In a typical CI patient the hair cells are damaged or absent. CIs make up for this loss by delivering electrical pulses to electrodes located inside the cochlea, which in turn stimulate auditory nerve cells to elicit hearing sensations [1,2]. Many studies have demonstrated that cochlear implantation improves the daily life of patients [3-5], and in particular allows young children with congenital deafness to experience almost normal hearing and speech d
%K Cochlear implant
%K EAP recording system
%K linearity
%K resolution
%K MED-EL PULSARCI100
%K Sigma-delta modulation
%K Adaptive sigma-delta modulation
%K Noise shaping
%K ECAP
%U http://www.biomedical-engineering-online.com/content/11/1/22