Travelling wave delay of the basilar membrane in age-related hearing loss

Abstract Objective To examine the effects of age and hearing loss on travelling wave delay by comparing frequency-specific action potential latencies obtained with electrocochleography. Methods A cross-sectional design was applied. Tympanic membrane electrocochleography recordings at 0.5 and 4 kHz were analysed in 85 ears from 49 adults. Participants were divided into four groups: older adults with hearing loss ( n = 22), older adults with normal hearing ( n = 18), younger adults with hearing loss ( n = 19) and younger adults with normal hearing ( n = 26). Results Age and hearing loss significantly influenced action potential latencies. At 0.5 kHz, the older adults with hearing loss showed the longest latencies ( p < 0.001). At 4 kHz, older adults with hearing loss differed from older adults with normal hearing ( p = 0.027). Travelling wave delay varied across groups ( p < 0.001), with the shortest travelling wave delay in younger adults with normal hearing and the longest travelling wave delay in older adults with hearing loss. Conclusion Ageing and hearing loss slow travelling wave velocity, providing an indirect but sensitive marker of early cochlear transmission deficits.