The cognitive impact of epileptiform EEG discharges and short epileptic seizures: relationship to characteristics of the cognitive tasks.

OBJECTIVE

We analyzed the effect of task dimensions (information processing demand; duration of the test; input modality) on the occurrence and cognitive impact of epileptiform EEG discharges (EEDs) or subtle epileptic seizures.

METHODS

One hundred ninety-nine children, aged 6-17 years, were included consecutively in a prospective standardized study. All children were assessed with EEG, which was synchronized with a computerized cognitive FePsy test system.

RESULTS

No association was found between the occurrence of EEDs or subtle epileptic seizures and the three task dimensions introduced in our study. The Computerized Visual Searching Task (CVST) appeared to be particularly sensitive to direct cognitive effects of EEDs. The CVST and the three memory tests--Corsi's Block Tapping and recognition of words/figures--were sensitive to the cognitive effects of subtle epileptic seizures.

CONCLUSION

Our results do not indicate a distinctive effect of information processing demand, duration of the test, or input modality on the occurrence of EEDs or subtle epileptic seizures. Effects on the impact on cognition are found when these three factors are combined.