Hearing aid-induced plasticity in the auditory system of older adults: Evidence from speech perception

Purpose: We tested whether using hearing aids can improve unaided performance in speech perception tasks in older adults with hearing impairment. Method: Unaided performance was evaluated in dichotic listening and speech-in-noise tests in 47 older adults with hearing impairment; 36 participants in 3 study groups were tested before hearing aid fitting and after 4, 8, and 14 weeks of hearing-aid use. The remaining 11 participants served as a control group and were similarly evaluated but were not fitted with hearing aids. Three protocols were compared in the study groups: amplification for the non dominant ear, amplification for the dominant ear, and bilateral amplification. Subsequently, after 4 weeks, all participants were afforded bilateral amplification. Results: In the study groups, unaided dichotic listening scores improved significantly in the non dominant ear by 8 weeks and onward. Significant improvements were also observed for unaided speech identification in noise, with some gains apparent after 4 weeks of hearing-aid use. No gains were observed in the control group. Conclusions: Using hearing aids for a relatively short period can induce changes in the way older adults process auditory inputs in perceptual tasks such as speech identification in noise and dichotic listening. These changes suggest that the central auditory system of older adults retains the potential for behaviorally relevant plasticity.