Implication of central asymmetry in speech processing on selecting the ear for cochlear implantation.
OBJECTIVE
Emerging evidence in auditory neuroscience suggests that central auditory pathways process speech asymmetrically. In concert with left cortical specialization for speech, a "right-ear advantage" in speech perception has been identified. The purpose of this study is to determine if this central asymmetry in speech processing has implications for selecting the ear for cochlear implantation.


METHODS
Retrospective cohort study.


METHODS
Academic university medical center


METHODS
One hundred one adults with bilateral severe-to-profound sensorineural hearing loss


METHODS
Cochlear implantation with the Nucleus 24 Contour device.


METHODS
Patients were divided into two groups according to the ear implanted. Results were compared between left-ear- and right-ear-implanted patients. Further subgroup analysis was undertaken, limited to right-handed patients. Postoperative improvement on audiograms and scores on speech perception tests (Hearing in Noise test, City University of New York in quiet and in noise test, Consonant-Vowel Nucleus- Consonant words, and phonemes) at 1 year was compared between groups. Analysis of covariance was used to control for any intergroup differences in preoperative characteristics.


RESULTS
The groups were matched in age, duration of hearing loss, duration of hearing aid use, percentage implanted in the better hearing ear, and preoperative audiologic testing. Postoperatively, there were no differences between left-ear- and right-ear-implanted patients in improvement on speech recognition tests.


CONCLUSIONS
Despite central asymmetry in speech processing, our data do not support a right-ear advantage in speech perception outcomes with cochlear implantation. Therefore, among the many factors in choosing the ear for cochlear implantation, central asymmetry in speech processing does not seem to be a contributor to postoperative speech recognition outcomes.
Morris
Luc G
LG
Department of Otolaryngology and Cochlear Implant Center, New York University School of Medicine, New York, New York 10016, USA.
Mallur
Pavan S
PS
Roland
J Thomas
JT
Waltzman
Susan B
SB
Lalwani
Anil K
AK
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001301:Audiometry, Pure-Tone; D019929:Cochlear Implantation / Q000295:instrumentation; D015331:Cohort Studies; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006319:Hearing Loss, Sensorineural / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013067:Speech Perception / Q000502:physiology*; D016896:Treatment Outcome