Impact of hearing aid processing delay on temporal and spectral auditory processing

Digital hearing aid processing introduces delay. While traditional literature suggests a 10-ms threshold, evidence indicates that even shorter delays may degrade sound quality. This study examined the impact of Ultra-Low Delay (ULD; 0.5 ms) versus Standard Delay (SD; 2.7 ms) on temporal and spectral auditory processing abilities in hearing aid users.

Twenty experienced hearing aid users (aged 41-75 years) with bilateral, symmetrical, mild-to-moderate sensorineural hearing loss participated. Auditory performance was assessed under the ULD and SD conditions using the Frequency Pattern Test, Duration Pattern Test, Random Gap Detection Test, and Spectral-Temporally Modulated Ripple Test.

Statistical analyses revealed significant differences between the two processing delay conditions across all evaluated tests (p < .01). Participants demonstrated statistically superior temporal and spectral processing performance under the ULD condition compared to the SD condition.

The findings demonstrate that the ULD condition significantly improves central auditory temporal and spectral processing abilities compared to the SD condition. These results challenge the traditional view that delays under 10 ms are negligible and highlight the clinical importance of ultra-low delay technology for preserving auditory resolution in individuals with hearing loss.