Open set speech perception with auditory brainstem implant?
OBJECTIVE
Only a small percentage of auditory brainstem implant (ABI) recipients treated for neurofibromatosis type 2 (NF2) have proved capable of identifying words using only the sound from the ABI. Recently, the ABI was applied to a series of patients with no cochlear nerve or with cochlear disorders that could not benefit from a cochlear implant (i.e., cochlear nerve aplasia or posttraumatic avulsion) or whose benefit was or would be severely compromised. A significant number of these patients have proven capable of understanding speech, including effortless telephone use. In the present study, a series of psychophysical tests were administered to determine the cause of the difference in performance between tumor (T) and nontumor (NT) ABI patients.


METHODS
Retrospective case review.


METHODS
Tertiary referral center.


METHODS
Twenty patients with ABIs participated in the investigation. Ten were NF2 patients and 10 NT subjects. Patient ages ranged from 24 to 61 years. Eleven were males and nine females.


METHODS
Auditory rehabilitation in auditory disconnection caused by cochlea or cochlear nerve disorders.


RESULTS
There was a significant correlation between modulation detection thresholds and speech understanding and a significant difference in modulation detection between T and NT patients.


CONCLUSIONS
The difference in modulation detection between the two groups suggests a difference in the survival of specific cells in the cochlear nucleus that support modulation. The pattern of results indicates a separate pathway of auditory processing that is specialized for modulated sounds, and that pathway is critical for speech understanding. In NF2 patients, the tumor and surgery may selectively damage this pathway, resulting in poor speech recognition with prosthetic stimulation.
Colletti
Vittorio
V
Department of Otolaryngology, University of Verona, Verona, Italy. vittoriocolletti@yahoo.com
Shannon
Robert V
RV
D000293:Adolescent; D000328:Adult; D000368:Aged; D038263:Auditory Brain Stem Implantation / Q000295:instrumentation*; D038262:Auditory Brain Stem Implants; D002648:Child; D002675:Child, Preschool; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006313:Hearing Loss, Central / Q000503:physiopathology / Q000534:rehabilitation*; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013067:Speech Perception / Q000502:physiology*; D016896:Treatment Outcome; D000160:Vestibulocochlear Nerve Diseases / Q000503:physiopathology / Q000534:rehabilitation*