Acta oto-laryngologica
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Acta oto-laryngologica · May 1997
Acute study on the neuronal excitability of the cochlear nuclei of the guinea pig following electrical stimulation.
To help deaf patients who cannot benefit from the cochlear implant due to interruption of the auditory nerve, a central auditory prosthesis has been developed to directly stimulate the cochlear nucleus in the brainstem. The electrode array lies on the surface of the cochlear nucleus and is designed to stimulate at 250 pulses/sec. To examine the safety of this prosthesis, guinea pig cochlear nuclei were stimulated acutely with bipolar surface electrodes using charge-balanced biphasic current pulses at rates of 250, 500 or 1,000 pulses/s and charge intensities of 1.8, 2.8, 3.5 or 7.1 microC/phase cm(-2). ⋯ However, a slight temporary reduction in the amplitude of the EABR waves was observed at 30-60 min during the course of acute stimulation using the highest charge density (7.1 microC/phase cm(-2)). This reduction showed a stronger correlation with the stimulus current, charge/phase and charge density than threshold. The present findings suggest that acute bipolar electrical stimulation with surface electrodes at rates up to 1,000 pulses/s and charge density up to 7.1 microC/phase cm(-2) is safe for neuronal excitability of the cochlear nucleus in guinea pig.