The Comparison between Visually and Auditory Oddball Tasks in the EEG Experiment with Healthy Subjects

The purpose of this study is estimating and comparing the three different dimensions of the EEG and studying the trials variability for two auditory and visually oddball tasks in the healthy subjects. They include regional as the region of the brain, longitudinal as the repetition of the stimuli, and functional as whole curve of Evoked Related Potential (ERP), dimensions.

The sample size is seventeen, with six females, in this three-trial study with standard and target stimuli per task. The dataset was downloaded from the internet and preprocessed. The Hybrid Principal Component Analysis (HPCA) decomposed the ERPs and estimated eigen components of three dimensions. The 95% Bayesian credible sets and trial effects as random effects of the first eigen component of each dimensions studied with the Generalized Additive Mixed Model (GAMM).

The p-values of the interaction effects between time and stimuli, repeats and stimuli and regions and stimuli are <0.05 for three dimensions, except in auditory task of longitudinal dimension and in visual task of regional dimension that are >0.05. The p-value of trial effects are <0.05 and for auditory task in the longitudinal dimension is borderline.  

The HPCA methodology decompose the time-domain ERPs to the functional-longitudinal and regional dimensions. The first eigencompments capture the most variations of every dimensions and we study the behavior of three-dimensions with them. We conclude that the repeating of the stimuli has a positive effect on the visual tasks. We also study the variability between trials with GAMM that are statistically significant.