Neural damage from continuous microstimulation in the cochlear nucleus; correlation with stimulus parameters

Seven hours of continuous stimulation in the cochlear nucleus with chronically implanted activated iridium microelectrodes resulted in neural injury characterized primarily by a localized zone of severe extracellular edema accompanied by abnormal cellular elements. The severity of the damage was correlated positively with the stimulus frequency and charge per phase, but a correlation with the geometric charge density was not obvious.