Impact of Various Frequency Allocation Tables on Pitch Perception in Post-Lingual Cochlear Implant Recipients: A Case Series Study

Background and Aim: Cochlear implants in post-lingually deaf patients often result in reduced hearing naturality compared to their previous acoustic hearing, making adaptation and speech perception challenging. This study aimed to evaluate participants’ perceptual ratings using Speech, Spatial Qualities (SSQ) 12 and the sound quality rating scale, alongside speech and pitch perception, across four different Frequency Allocation Tables (FAT). Methods: Four post-lingual Cochlear Implant (CI) users completed subjective ratings using the Speech, Spatial, and Qualities of Hearing Scale (SSQ 12) and the speech quality rating scale, while objective tests, including speech perception scores in quiet and noise, and psychophysical assessments like pitch perception tasks, were conducted across the four FATs. Results: Performance using logarithmic FAT was better across all the domains of SSQ 12 and speech quality rating scale and in Signal to Noise Ratio (SNR) at both 0 and +10 dB. Pitch perception across four FATs reveals a statistically significant difference noted in the apical electrode score when compared with medial and basal electrodes across all the FATs. Conclusion: The default FAT provided by the manufacturer may not be suitable for all users due to several factors such as length of the electrode array, shallow insertion of electrodes. Thus, all the FAT options must be utilized and tested for subjective, objective, and psychophysical performance and the best suitable FAT should be set for the specific patient.