Cochlear pathology. Hazards of long-term implants.

There is increasingly diverse evidence that multichannel intrascalar or modiolar implants can cause long-term changes in cochlear structure. Experimental studies show that nerve-cell loss and osteogenesis are related to electrical stimulation. Low charge densities may limit such intracochlear changes. Middle-ear stimulation presents an alternative to the intracochlear implant, although its degree of effectiveness is not well characterized. Monitoring electrically produced auditory brain-stem responses may help detect progressive pathologic changes occurring in the implanted cochlea.