Evolution of absolute and relative power and indices of electroencephalographic rhythms in elementary, college, and graduate students

Héctor Brust-Carmona , Marlene Galicia-Alvarado , Javier Alfaro Belmont, Ana Sánchez-Quezada , Jesica Cantillo-Negrete , Oscar Yáñez-Suárez

DOI: https://doi.org/10.17711/SM.0185-3325.2015.065


Antecedents. Cerebral function results from the electrical activity in glial-neuronal networks, integrated proactively through sensory, motor, and regulating interactions. These networks oscillate since early life and are modulated by diverse maturation factors, including educational processes.

Objective. To identify the power spectrum separated in delta (δ), theta (θ), alfa 1 (α1), alfa 2 (α2), beta 1 (β1) y beta 2 (β2), and their topography in cerebral hemispheres of children, youngsters, and adults to establish qEEG indicators.

Method. We studied three groups of 16 participants each: elementary school children (CG), undergraduate students (UG), and graduate students (GG). Parents and participants granted their consent. The EEG was recorded (Nicolet) following the 10/20 system. Bipolar samples were analyzed. Absolute power (AP) was obtained with Fourier transform; its average (AAP) relative power (RP), and slow/fast frequencies and indices were calculated. Differences were assessed with Kruskal Wallis and Dunnet’s comparison for subgroups.

Results. The AAP of six frequencies was higher in CG than in UG and GG. Frequencies were similar with exceptions correlating with topographic distribution. The δ/α index was higher in CG with a particular topographic distribution, θ/α varied more. RP of α was higher in UG and GG than in CG; that of θ and δ were higher in some leads of CG.

Discussion and conclusion. During cerebral maturation, AP diminishes due to integration of more glial-neuronal ensembles, presenting greater asymmetry in a giving frequency. These profiles establish indicators for comparison with future EEG recordings.


qEEG power spectrum; qEEG indicators; alpha and beta 1; delta and theta index over alpha