Spectral and temporal measures in hybrid cochlear implant users:  on the mechanism of electroacoustic hearing benefits.
OBJECTIVE
Compare auditory performance of Hybrid and standard cochlear implant users with psychoacoustic measures of spectral and temporal sensitivity and correlate with measures of clinical benefit.


METHODS
Cross-sectional study.


METHODS
Tertiary academic medical center.


METHODS
Hybrid cochlear implant users between 12 and 33 months after implantation. Hybrid recipients had preservation of low-frequency hearing.


METHODS
Administration of psychoacoustic, music perception, and speech reception in noise tests.


METHODS
Performance on spectral-ripple discrimination, temporal modulation detection, Schroeder-phase discrimination, Clinical Assessment of Music Perception, and speech reception in steady-state noise tests.


RESULTS
Clinical Assessment of Music Perception pitch performance at 262 Hz was significantly better in Hybrid users compared with standard implant controls. There was a near significant difference on speech reception in steady-state noise. Surprisingly, neither Schroeder-phase discrimination at 2 frequencies nor temporal modulation detection thresholds across a range of frequencies revealed any advantage in Hybrid users. This contrasts with spectral-ripple measures that were significantly better in the Hybrid group. The spectral-ripple advantage was preserved even when using only residual hearing.


CONCLUSIONS
These preliminary data confirm existing data demonstrating that residual low-frequency acoustic hearing is advantageous for pitch perception. Results also suggest that clinical benefits enjoyed by Hybrid recipients are due to improved spectral discrimination provided by the residual hearing. No evidence indicated that residual hearing provided temporal information beyond that provided by electric stimulation.
Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, Washington 98195, USA.
Justin S
JS
Golub
Jong Ho
JH
Won
Ward R
WR
Drennan
Tina D
TD
Worman
Jay T
JT
Rubinstein
D000158:Acoustic Impedance Tests; D000368:Aged; D001301:Audiometry, Pure-Tone; D001307:Auditory Perception / Q000502:physiology*; D001309:Auditory Threshold; D003054:Cochlear Implants; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006309:Hearing / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009146:Music; D009622:Noise; D010897:Pitch Discrimination / Q000502:physiology; D011571:Psychoacoustics; D013067:Speech Perception / Q000502:physiology; D016896:Treatment Outcome