Information processing during two types of EEG activity.
A 15-year-old girl whose EEG contained frequent bursts of generalized sub-clinical spikewave activity was examined on a paced serial-choice response task with simultaneous EEG control. The task was carried out at three different speeds and three different information loads. Performance was compared during paroxysms of spike-wave activity and during normal EEG background activity. Four parameters of performance were compared, each parameter being somewhat differently affected by spike-wave activity. "Response ambiguity" was significantly increased in the presence of spike-wave activity, with a corresponding decrease in the amount of "information transmitted". The "absolute rate" at which information could be transmitted in relation to presentation rate was consequently reduced during spike-wave activity, the effect being most marked at the intermediate speed of presentation (1 signal/2 sec). However, when signals were presented very slowly (1/4 sec) the child's "relative information transmitted" during spike-wave activity approached that achieved under normal background conditions. Thus, accuracy of performance per se is not critically affected by spike-wave; rather it is the rate at which signals can be handled. Spike-wave may therefore be conceptualized as a form of "neural noise" whose effect is to reduce a subject's channel capacity.
D000293:Adolescent; D001288:Attention / Q000503:physiopathology; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007257:Information Theory; D009433:Neural Inhibition; D011930:Reaction Time; D012153:Retention, Psychology; D009435:Synaptic Transmission; D013850:Thinking / Q000502:physiology*