Age-Related Discrimination of Visual-Evoked Potentials Using Cross-Coherence Analysis

Cross-coherence is used to evaluate the correlation between two sources of signals and to evaluate the power transfer between input and output of two linear sources. Visual evoked potential (VEP) is used to study the visual pathway of patients according to the ISCEV standard.

The cross-coherence analysis is used to examine the interconnections between channels across two age groups mature and young.

This experimental and analysis study implements a statistical method based on coherence analysis horizontally, vertically, and diagonally across the brain hemisphere. It investigates and discriminates the VEP responses related to age in two groups, matured and young.

The coherence results compared in both the time and frequency domains for the two age groups. In the young age group, there is greater coherence between the occipital lobes compared to the frontal lobes in horizontal coherence. The diagonal coherence in the young age group was less than 0.4, whereas it exceeded 0.4 and 0.5 in the mature age group for the time and frequency domains, respectively.

The frequency coherence shows the spectrum of an alpha wave of frequency 15 Hz in the matured group. The vertical coherence of matured age group shows an extra peak in the range of late Alpha wave at 25 Hz compared to that in the young age group. The diagonal coherence shows the frequency peak of the Alpha wave at 15 Hz in the matured age group. While the young group shows the late Alpha wave at around 25 Hz.