Current steering creates additional pitch percepts in adult cochlear implant recipients.
OBJECTIVE
The number of spectral channels is the number of discriminable pitches heard as current is delivered to distinct locations along the cochlea. This study aimed to determine whether cochlear implant users could hear additional spectral channels using current "steering." Current steering involves the simultaneous delivery of current to adjacent electrodes, where stimulation can be steered to sites between the contacts by varying the proportion of current delivered to each electrode in an electrode pair. Current steering may increase the number of spectral channels beyond the number of fixed electrode contacts.


METHODS
Prospective clinical study.


METHODS
Twelve tertiary care centers in North America.


METHODS
The subjects were 106 adults with postlingual onset of severe-to-profound hearing loss.


METHODS
Subjects received the Advanced Bionics CII or HiResolution 90K device (Advanced Bionics Corporation, Valencia, CA, USA).


METHODS
After loudness balancing and pitch ranking the 3 electrode pairs (2 and 3, 8 and 9, and 13 and 14), the subjects identified the electrode with the higher pitch while current was varied proportionally between the electrodes in each pair. The smallest change in proportion yielding a discriminable change in pitch was defined as the spectral resolution.


RESULTS
The data from 115 ears indicate that the number of spectral channels averaged 3.8 for the basal pair, 6.0 for the midarray pair, and 5.3 for the apical pair. Assuming that the number of channels on these 3 electrode pairs represents the entire array, the total potential number of spectral channels was calculated and ranged from 8 to 451, with an average of 63.


CONCLUSIONS
These results indicate that additional pitch percepts can be created using current steering.
Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St.Louis, Missouri 63110, USA. firsztj@wustl.edu
Jill B
JB
Firszt
Dawn Burton
DB
Koch
Mark
M
Downing
Leonid
L
Litvak
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019929:Cochlear Implantation / Q000295:instrumentation; D003054:Cochlear Implants; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000601:surgery*; D006801:Humans; D008144:Loudness Perception; D008297:Male; D008875:Middle Aged; D010898:Pitch Perception; D011446:Prospective Studies; D011474:Prosthesis Design; D012720:Severity of Illness Index