Successful cochlear implantation in two profoundly deafened patients with neurofibromatosis type 1: further evidence to support a cochlear site of lesion.

OBJECTIVE

To investigate the usefulness of cochlear implantation and to examine the evidence for a cochlear or retrocochlear site of lesion for deafness in Neurofibromatosis Type 1 (NF1).

PATIENTS: Two profoundly deafened NF1 patients who underwent cochlear implantation.

INTERVENTIONS: Preoperative electrophysiologic and audiologic evaluation including pure-tone audiometry, auditory brainstem response, speech audiometry, otoacoustic emission, and promontory stimulation test. Intraoperative electrophysiologic tests were also performed.

MAIN OUTCOME MEASURES: Results of preoperative diagnostic workup. Cochlear implant performances were evaluated in the auditory-only condition in both closed-set and open-set formats.

RESULTS

Preoperative diagnostic assessment suggested cochlear impairment with preserved auditory pathway at the basis of the sensorineural hearing loss in both patients. Intraoperative electrically evoked auditory nerve and brainstem responses confirmed the integrity of the neural population all along the length of the cochlea. To date, with a follow-up of 2 and 10 years, both patients gained excellent open-set, auditory-only, speech understanding and were able to converse on the telephone without a code.

CONCLUSION

Cochlear impairment with preserved auditory pathways can be responsible for sensorineural hearing loss in NF1 patients. When their hearing deficit meets criteria for cochlear implantation, this type of auditory rehabilitation can restore social hearing in these patients while dramatically improving their quality of life.