Cochlear implants in five cases of auditory neuropathy: Postoperative findings and progress

Objectives: To review our experiences with some of the preoperative and pos toperative findings in five children who were diagnosed with auditory neuro pathy and were provided with cochlear implants. We describe changes in audi tory function, which enabled these children to have significant improvement in their hearing and communication skills. Study Design: Pre- and postoper atively, these children received complete medical examinations at Mayo Clin ic, including related consultations in audiology, pediatrics, neurology, me dical genetics, otolaryngology, psychology, speech pathology, and radiology . Methods: These children typically had additional medical and audiological examinations at more than one medical center. The hearing assessments of t hese children included appropriate behavioral audiometric techniques, objec tive measures of middle ear function, acoustic reflex studies, transient (T OAE) or distortion product (DPOAE) otoacoustic emissions, auditory brainste m responses (ABR), and, in some cases, transtympanic electrocochleography ( ECoG). After placement of the internal cochlear implant devices (Nucleus CI 24), intraoperatively we measured electrode impedances, visually detected e lectrical stapedius reflexes (VESR) and neural response telemetry (NRT). Th ese intraoperative objective measures were used to help program the speech processor for each child. Postoperatively, each child has had regular Follo w-up to assure complete healing of the surgical incision, to assess their g eneral medical conditions, and for speech processor programming. Their hear ing and communication skills have been assessed on a regular basis. Postope ratively, we have also repeated electrode impedance measurements, NRT measu rements, otoacoustic emissions, and electrical auditory brainstem responses (EABR). We now have 1 year or more follow-up information on the five child ren. Results: The five children implanted at Mayo Clinic Rochester have not had any postoperative medical or cochlear implant device complications. Ah of the children have shown significant improvements in their sound detecti on, speech perception abilities and communication skills. Ad of the childre n have shown evidence of good NRT results. Ad but case D ((who was not test ed) showed evidence of good postoperative EABR results. Otoacoustic emissio ns typically remained in the non-operated ear but, as expected, they are no w absent in the operated ear. Conclusion: Our experiences with cochlear imp lantation for children diagnosed with auditory neuropathy have been very po sitive. The five children we have implanted have not had any complications postoperatively, and each child has shown improved Listening and communicat ion skills that have enabled each child to take advantage of different comm unication and educational options. Key Words: Auditory neuropathy, cochlear implants, stapedius reflexes, otoacoustic emissions, neural response telem etry, electrical auditory brainstem responses.