engleski

Computerized Driving Analysis (CDA) of EEG with Intermittent Light Stimulation (ILS) in Patients with Ischaemic Cerebrovascular Accidents

In line with the past experience that unilateral hemispheric damage reduces the brains capacity to follow rhythmic ILS (asymmetric response in photic driving or following) ; we tried to develop a method which could give us objective parameters indicating the degree and the quality of the lesion. In a population with ischaemic hemispheric cerebrovascular lesions we used the method of CDA in a standardized procedure of ILS: stimulation at the frequency of the persons background alpha rhythm, and at half and at double of its value. After recording the EEG with a 16 channels Elema Mingograph, the data contained in 10 sec. periods were processed in a digital computer PDP LAB 8/E. A program was developed, which provided: a) the mean value of periodic component evoked by rhythmic light stimulation during the time interval between the two subsequent stimuli, b) its standard deviation and c) its trend for the defined frequency. Special attention was paid to the amplitude and phase characteristics of the evoked mean components. The results were compared with the compressed sequential frequency analysis obtained on the same data, with this analysis same parameters were specially evaluated. The mean frequency, their standard deviation, energy development in time within the EEG frequency bands, together with the alpha, alpha/2 and 2*alpha components of the subsequent power spectrum. The CDA parameters were also compared with the standard VEP-s. The method makes it possible to obtain a better insight into the synchronization capacity of the brain, indicating the degree and the quality of the damage of respective synchronizing structures.

eeg driving; eeg sinchronisation

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