Research On 40Hz ERPs In The Cognitive Eeg

Paroxysmal 40Hz event related potential (40Hz ERPs) are seen in EEG of cognitive activities which related to attention. It has the potential to be a reliable indicator of assessment of some cognitive function in further study, which used for diagnosis and treatment of diseases related to cognitive impairment and attention disorder. The research of the validity and sensitivity of parameters which evaluate 40Hz ERPs under cognitive tasks, such as visual, hearing, memory and calculation will be useful for assessment of cognitive function level.In this paper, experiments of acquisition of cognitive EEG were designed and completed, 48 groups of cognitive EEG data under 12 different cognitive tasks collected, 40Hz ERPs extracted and analyzed, five parameters calculated, the validity and sensitivity of parameters compared and analyzed.EEG signal is very small, of which, paroxysmal 40Hz ERPs is smaller, and apt to be interfered by kinds of artifacts, the extraction and processing of which is very important. In this paper, EEG signal processing techniques were described in detail, and several examples of some of which given, the advantages and disadvantages and application of these methods pointed out.Of the parameters which evaluate 40Hz ERPs, average area and mean absolute amplitude are sensitive to cognitive tasks, the 40Hz narrow-band power and peak power less sensitive, the duration percent of 40Hz ERPs least.For the same subject, under different cognitive tasks, levels of the parameters are different. Under simple cognitive tasks such as eyes closed, quiet and low attention, simple thinking, levels of the parameters are low, on the contrary, the levels high.The cognitive tasks which have great differences should be chose for cognitive function tests. Area and mean absolute amplitude are effective to evaluate level of 40Hz ERPs, they are expected to be used in clinical after further experimental study.