Impact of age and sensory loss on brain plasticity in ARHL

Introduction Age-related hearing loss can cause intramodal and cross-modal reorganization of the brain in deafness. However, sensory loss and age both can have an impact. So far, the results concerning the reorganization at an early stage of hearing loss are contradictory, and age has not been clearly considered.

Method In the present study, amplitudes and latencies of P100, N100 and P200 of visually evoked potentials (VEP) were assessed in temporal (T7, T8) and occipital (Oz) electrodes in a 29-channel EEG in 35 normal hearing (NH) (mean=62.1 (7.48); 4PTA<25 dB) and in 23 mild hearing-impaired subjects (HI) (mean=74.1 (8.64); 4PTA 26- 40 dB) and compared between groups.

Results Longer latencies of P100 and of N100 at occipital electrode Oz were observed in mild HI compared to controls (p=0.011 and p=0.023). Both latencies strongly correlated with age (r=0.344, p=0.008, r=0.345, p=0.008, respectively), but after controlling for age there were no longer differences between groups (p>0.05). However, group differences in amplitude of N100 at T7 (p=0.003) persisted even after controlling for age (r=0.822, p<0.001). This amplitude significantly correlated positively with age (t=-2.658, p=0.013) and negatively with hearing loss assessed by 4PTA (t=4.12, p<0.001).

Conclusion Opposite effects of age and hearing loss observed in the temporal area in response to visual stimulation suggest a dynamic interaction between both factors that might play a role in the trajectory of cross-modal plasticity in ARHL.

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Artikel online veröffentlicht:
19. April 2024