Optimizing fitting in children using objective measures such as neural response imaging and electrically evoked stapedius reflex threshold

Abstract

OBJECTIVE: To study over time correlations between Compound Action Potential measured through Neural Response Imaging (NRI) and electrically Evoked Stapedius Reflex Thresholds (eSRT) and psychophysical measurements to develop guidelines for using those objective measures to optimize HiRes programs in patients implanted with Advanced Bionics CII-Bionic Ear or a HiRes90K cochlear implants. PATIENTS: Fifteen pediatric subjects, all implanted with a CII-Bionic Ear or a HiRes90K. INTERVENTIONS: NRI was measured on 4 electrodes intraoperatively at first fitting and after 3, 6, and 12 months of use. eSRT recordings were performed intraoperatively with SoundWave speech bursts. Subjects were fitted using the SoundWave defaults. Relationships between NRI thresholds (tNRI), eSRT, and most comfortable levels (M) are presented. MAIN OUTCOME MEASURES: Intraoperative eSRT, and intraoperative and postoperative tNRI at each fitting session. Auditory performance measured by Categories of Auditory Performance and Meaningful Auditory Integration Scale. RESULTS: First fitting Ms are 97% of intraoperative tNRI; stable Ms (12 months of implant use) are equal to 115% of 12 months' tNRI and to 76% of intraoperative eSRT on average across the electrode array with great intersubject variability. CONCLUSION: The results show that single-channel tNRI and eSRT values can be clinically useful for programming cochlear implants in children, although this should be done with caution as there is considerable interpatient variability. © 2007 Otology & Neurotology, Inc.