Cochlear implantation influences contralateral hearing and vestibular responsiveness

A cochlear implant program has been carried out at the ORL Clinic of Semmel weis University in Budapest since 1985. Different devices and techniques ha ve been used in pre- and postlingual children and adults. Over the last 6 y ears contralateral hearing improvement has been observed in 18 patients. Th is phenomenon can usually be demonstrated 6 months after the operation. Sin ce our first observation several other authors have confirmed this phenomen on. However, the underlying mechanism is still obscure; both the efferent i nnervation and the plasticity of the brain may be important factors. The ve stibular function of cochlear implant candidates was checked routinely pre- and postoperatively and changes in vestibular responsiveness were observed . Over the last 3 years air-caloric stimulation has been performed by means of a computer-based ENG system. In most patients the vestibular function w as unchanged after the implantation, but in some cases a significant improv ement in vestibular responsiveness was noted. Here we briefly describe case s of re-implantation carried out at the clinic. All the patients obtained b etter speech discrimination scores after having been implanted with intraco chlear devices. None of the patients suffered any inner ear abnormality due to the first implant.