Analysis of the dynamical behaviour of the EEG rhythms during a test of sustained attention.

In clinical routine, the evaluation of sustained attention is often performed analyzing behavioral data collected during specific tests. It is not common to match such analyses with a detailed examination of the subject's simultaneous electroencephalographic (EEG) activity, and particularly its frequency content. In this study, 9 healthy volunteers underwent a modified Conners' CPT test, while their EEG were contemporarily recorded. Spectral power was calculated for each of the recorded EEG signals, with particular attention to frequency bands that are traditionally reported in literature. Then Compressed Spectral Array (CSA) sequence of spectra was plotted, and the analysis of the variability of the rhythms was carried out. Evaluation of the obtained results shows that the nine subjects shared a progressive backshift of alpha rhythm during the accomplishment of the CPT test. Moreover, beta and gamma activities were stronger in the right than in the left hemisphere. An intense and widespread decrease in EEG spectral power during test performing became visible in many subjects. Statistical analysis provided evidence that EEG activity correlates with the test behavioral results in many cerebral areas. For this reason, we encourage further investigations of the combined employment of tests and EEG recording during the clinical assessment of sustained attention performance.