The threshold and the growth of amplitude of the cortical evoked potential were used to evaluate in the guinea pig several positions for stimulus electrodes. These electrode positions were similar to those employed in reports of electrical stimulation of the ears of deaf patients. The lowest thresholds were obtained with electrodes in the modiolus; the highest, with two electrodes in the same scala. Intermediate thresholds were obtained with electrodes spanning the cochlear partition or with one stimulus electrode in nearby muscle. Electrode position had little effect on the growth of amplitude of the evoked potential, once threshold had been surpassed. The range from threshold to the stimulus intensity that produced a maximum amplitude evoked potential was 6 to 20 dB.
Walloch RA, Cowden DA. Placement of Electrodes for Excitation of the Eighth Nerve. Arch Otolaryngol. 1974;100(1):19–23. doi:10.1001/archotol.1974.00780040023004
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