Anatomy-based fitting improves speech perception in noise for cochlear implant recipients with single-sided deafness.

Objective: To evaluate objective and subjective hearing outcomes in experienced cochlear implant users with single sided deafness (SSD CI) who used fitting maps created via anatomy-based fitting (ABF) and clinically-based fitting (CBF).

Participants: Twelve SSD CI users with postlingual hearing loss.

Intervention: OTOPLAN (Version 3. (MED-EL) was used to determine intracochlear electrode contact positions using post-operative high-resolution flat panel volume computed tomography. From these positions, the corresponding center frequencies and bandwidths were derived for each channel. These were implemented in the clinical fitting software MAESTRO to yield an ABF map individualized to each user.

Main outcome measures: ABF and CBF maps were compared. Objective speech perception in quiet and in noise, binaural effects, and self-perceived sound quality were evaluated.

Results: Significantly higher speech perception in noise scores were observed with the ABF map compared to the CBF map (mean SRT₅₀: -6.49 vs. -4.8 dB SNR for the S₀N_CI configuration and - 3.85 vs. -2.75 dB SNR for the S₀N₀ configuration). Summation and squelch effects were significantly increased with the ABF map (0.86 vs. 0.21 dB SNR for summation and 0.85 vs. -0.09 dB SNR for squelch). No improvement in speech perception in quiet or spatial release from masking were observed with the ABF map. A similar level of self-perceived sound quality was reported for each map. Upon the end of the study, all users opted to keep the ABF map. This preference was independent of the angular insertion depth of the electrode array.

Conclusions: Experienced SSD CI users preferred using the ABF map, which gave them significant improvements in binaural hearing and some aspects of speech perception.