Quantitative Electroencephalographic Amplitude Measures in Young Adults During Reading Tasks and Rest

Résumé

Background. Previous studies have observed differences in the quantitative electroencephalogram (qEEG) between individuals with reading difficulties and non-clinical controls during reading tasks. However, little has been reported about the qEEG of reading tasks compared to qEEG at rest across a wide range of EEG frequencies. The present study explored the qEEG differences between resting and reading states in a group of 19 non-clinical college students. The purpose was to investigate the amplitude changes across five frequency bands: 8 to 10, 10 to 12, 12 to 21, 21 to 32, and 38 to 42 Hz. Methods. Nineteen channels of EEG were recorded at 256 samples per second during an initial resting baseline, during five different reading tasks while selectively engaging the visual, phonetic, and semantic modalities, and during a second resting baseline. Absolute EEG amplitude was measured as the dependent variable. Ninety ANOVAs (taskchannel) were computed, comparing each reading task to each baseline, for each frequency band, for each of three cortical areas, frontal, centro-coronal, and posterior. Single-channel t-tests were computed for significant ANOVAs. Results. ANOVA analyses revealed significantly less amplitude for the 10 to 12 Hz band during all three reading tasks as compared to the second baseline. Single-channel t-tests showed this phenomenon to be lateralized towards the left hemisphere. Conclusions. Results are interpreted as a manifestation of language specific processing for the 10 to 12 Hz band. The absence of amplitude changes in the 12 to 21 Hz band was interpreted as motor inhibition. It is suggested that future studies employ a post-task baseline when studying cognitive tasks.