Competition for neuronal processing time: a physiological seizure control mechanism?

ABSTRACT

Cognitive means for seizure control remain underinvestigated in clinical epileptology. Since administration of a complex reaction time (CRT) test triggered by a seizure detection algorithm is a unique research paradigm, its effects on seizure frequency and severity were examined in 14 subjects undergoing invasive epilepsy surgery evaluation. These variables were compared with those of 37 subjects evaluated using the same surgical protocol, but to whom the CRT test was not administered. The results were analyzed for statistical significance using the t-test and the chi-squared test. Eight of fourteen subjects who took the CRT test had fewer than 5 clinical seizures, and 7 of 14 subjects had fewer than 5 clinical and subclinical seizures over 8.9 days compared with 37 subjects who did not take this test, each of whom had a minimum of 5 clinical seizures over 6.7 days (chi-square=25.08; p<0.001). The monitoring duration difference (2.2 days longer for CRT test takers) was statistically significant (p~0.04). In one subject, seizure severity was lower (p<0.001) during testing compared with nontesting periods. It is posited that seizure frequency reduction is a beneficial, unconditioned, and, probably, contingent effect of the CRT test. These and other experimental observations form the basis for a hypothetical physiological antiseizure mechanism, the "competition for neuronal processing time".