Bilateral Cochlear Implants Using Two Electrode Lengths in Infants With Profound Deafness.

OBJECTIVE: The goal of this investigation was to determine if a short electrode in one ear and standard electrode in the contralateral ear could be an option for infants with congenital profound deafness to theoretically preserve the structures of the inner ear. Similarities in performance between ears and compared with a control group of infants implanted with bilateral standard electrodes was evaluated.

STUDY DESIGN: Repeated-measure, single-subject experiment.

SETTING: University of Iowa-Department of Otolaryngology.

PARTICIPANTS: Nine infants with congenital profound bilateral sensorineural hearing loss.

INTERVENTION(S): Short and standard implants.

MAIN OUTCOME MEASURE(S): Early speech perception test (ESP), children's vowel, phonetically balanced-kindergarten (PB-K) word test, and preschool language scales-3 (PLS-3).

RESULTS: ESP scores showed performance reaching a ceiling effect for the individual short and standard ears and bilaterally. The children's vowel and PB-K word results indicated significant (both p < 0.001) differences between the two ears. Bilateral comparisons to age-matched children with standard bilateral electrodes showed no significant differences (p = 0.321) in performance. Global language performance for six children demonstrated standard scores around 1 standard deviation (SD) of the mean. Two children showed scores below the mean, but can be attributed to inconsistent device usage. Averaged total language scores between groups showed no difference in performance (p = 0.293).

CONCLUSIONS: The combined use of a short electrode and standard electrode might provide an option for implantation with the goal of preserving the cochlear anatomy. However, further studies are needed to understand why some children have or do not have symmetric performance.