Temporal processing and speech perception through multi-channel and channel-free hearing aids in hearing impaired

Objective: To compare the temporal processing skills and speech in noise perception of hearing-impaired individuals through channel free and multichannel hearing aids. Design: A quasi-experimental study. Study sample: Twenty-one participants with sensory neural hearing loss were involved in the study. They were subjected to a series of temporal processing (TMTF, GDT & CMR-UCM/CM) and speech in noise test using a multichannel and channel-free hearing aid. Subsequently, they rated sound quality and hearing aid preferences. Objectively, the hearing aid signal output was acoustically analysed for modulation detection and gap detection tasks. Results: In all the test, participants manifested equal performance with the tested devices except CMR-CM task where channel-free outperformed. Acoustic analysis showed evidence of spectral and temporal distortion in channel-free hearing aid, similar to multichannel hearing aids. Finally, channel free was the most preferred hearing aid by less experienced participants. Conclusion: All the measures indicated similar performance across the tested devices and complemented one another in their explanation of study findings. Faster gain adjustments of channel free across the frequency facilitated better-comodulated masking release than that achieved with MCC. Preference for the sound quality of the channel free was based on factors, usually subjective. Channel-free hearing aid depicted spectral and envelope distortion, like MCC.