Differences between electrode-assigned frequencies and cochlear implant recipient pitch perception.
CONCLUSIONS
This study demonstrated an evident mismatch between frequencies assigned to electrodes and frequencies evoked by stimulation of those same electrodes in implanted patients. We propose that the mapping procedures should include, whenever possible, a comparison with homolateral residual hearing in order to obtain an appropriate frequency range assignation for each electrode.


OBJECTIVE
The study aimed to investigate the correspondence between the frequencies assigned to each electrode and those actually perceived by the cochlear implant patient.


METHODS
We studied five post-lingually deaf adults with detectable residual hearing in the implanted and in the contralateral ear, who had each received a Cochlear implant. An ACE standard setting was used for mapping. The patients were asked to match the electric pitch with the acoustic one following presentation of pure tones to both the implanted and the contralateral ear.


RESULTS
In almost all patients the two most apical electrodes evoked higher frequencies than those assigned by the mapping software (E22 = 188-313, E21 = 313-438 Hz). Therefore, electric stimulation seems not to determine pitch sensations for frequencies <500 Hz. For most electrodes there is no correspondence between the acoustic pitch and the assigned frequency ranges. Moreover, these results were almost always different when stimulating the implanted and the contralateral ear.
Nardo
Walter Di
WD
Institute of Otorhinolaryngology, Catholic University of the Sacred Heart, Rome, Italy.
Cantore
Italo
I
Cianfrone
Francesca
F
Melillo
Pietro
P
Fetoni
Anna Rita
AR
Paludetti
Gaetano
G
D000328:Adult; D001301:Audiometry, Pure-Tone; D003054:Cochlear Implants; D003638:Deafness / Q000534:rehabilitation*; D004292:Dominance, Cerebral; D004567:Electrodes, Implanted; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010898:Pitch Perception; D012984:Software; D013018:Sound Spectrography