Assessing the auditory cortical plasticity in presbycusis using the P3 late evoked potential / Zainab Tarek Sayed Abdelaleim ; Supervised Mostafa Elkhousht Mahmoud Mourad , Abeir Osman Dabbous , Hussien Sherif Mohammad Hamdy

Thesis (M.Sc.) - Cairo University - Faculty of Medicine - Department of E.N.T

Background: Aging and hearing loss both affect the central auditory pathway. Objective:To determine the extent of cortical plasticity and reorganization in response to auditory deprivation in presbycusis, using P3 at the edge frequency of slopingsensorineural hearing loss(SNHL). Methods: 20 elderly patients with high frequency SNHLwere compared to 20 age-matched controls and to 20 adult controlswith normal hearing threshold level. P3 at small frequency changes between the common and rare stimuli (20 % &5 % &2%)above the edge frequencyof hearing loss,word discrimination score (WDS) and Speech in noise (SPIN) test at SNR 0 &-10 were done. Results:The elderly controls had a significant smaller P3 amplitude especially in 20 % higher change condition, and increased P3 latency at 2 % condition only than the adult controls, reflecting effect of aging on P3.A statistically significantly Larger P3 responses were detected in response to small frequency changes in the Patients group compared to the elderly controls groupwhile the amplitudeswere comparable to the adult controls. Thiscould be either due enhanced cortical representation of frequency at the edge frequency of the high frequency SNHL or due to the increased loudnessof the rare stimulus frequency than that of the edge frequency, adding loudness difference to the frequency difference between rare and common stimuli

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