A cochlear implant wherein the return path of the electrode array is
located to increase current flow through the modiolus. The return
electrode is placed at various locations outside the cochlea, and into
the modiolus itself. In addition, the electrode array includes an
inflatable membrane that is inflated to anchor the array in position in
the cochlea with the electrode contacts pressed into contact with the
modiolar wall and allowing the membrane to seal with the surrounding
tissue of the cochlea, increasing the longitudinal resistance along the
cochlear implant electrode, decreasing shunting of the injected current
via scala tympani. In experiments that were conducted the current along
the modiolus was determined to be, on average, 2.4 times larger with the
return electrode in the modiolus than in an extracochlear location.