The influence of epileptiform activity on indicators of intellectual development in children with age-dependent childhood focal epilepsy syndromes

Introduction. Age-dependent focal epilepsy in childhood (ADFEC) is the most common epileptic syndrome in childhood, accounting for about 15-20% of all forms of the disease in this age cohort. Special attention in the problem of ADFEC is paid to epileptiform activity, which tends to increase its severity during slow-wave sleep, whose effect on the neuro-cognitive development in patients is actively discussed today and requires further study. It has also been established that in some patients with ADFEC, during the active stage of the disease, it is possible to form the phenomenon of prolonged spike-wave activation during sleep, characteristic of the eponymous epileptic encephalopathy syndromes.

Objective. To evaluate the effect of epileptiform activity on the state of intellectual functions in children with ADFEC syndromes.

Materials and methods. The study included thirty four children with age-dependent focal epilepsy of childhood; the diagnosis was based on medical history, neurological and instrumental examinations in accordance with the ILAE criteria of 2022. All children underwent video EEG monitoring of sleep to calculate the spike wave index (SVI), a study using the Wechsler intelligence test, the children’s version (WISC-II) and the Vineland-2 adaptive behavior scale (VABS-2).

Results. An increase in SVI of more than 50% was observed in 13 patients (38.2%), and in 8 patients the phenomenon of prolonged spike wave activation during sleep (23.2%) was recorded. When studying the level of intelligence using the Wechsler method (WISC-2), the following average values were obtained: verbal IQ — 103.15, non-verbal IQ — 111.03, general IQ — 107.12. Inverse correlations have been revealed between the value of SVI and indicators of intellectual development, SVI and indicators of adaptive behavior.

Conclusion. A high level of SVI has a significant impact on the indicators of intellectual development in children with ADFEC syndromes. The inverse correlation between SVI values and IQ indicators indicates to the importance of controlling the epileptiform activity index to prevent cognitive impairment, which is especially important not only for children with epileptic encephalopathy syndromes with spike-wave activation during sleep, but also for ADFEC patients. A significant decrease in IQ scores with age has been found in children with ADFEC syndromes, which requires further study.

Compliance with ethical standards. The study was conducted in accordance with the principles of the Declaration of Helsinki. All patients or their legal representatives signed voluntary informed consent.

Contribution:
Maslov M.S. — data collection and analysis, review of publications, writing the text of the manuscript;
Kholin A.A. — data analysis, writing the text of the article, final approval for the publication of the manuscript; 
Zavadenko N.N. — writing the text of the article, final approval for the publication of the manuscript.
All co-authors — approval of the final version of the manuscript, responsibility for the integrity of all parts of the manuscript.

Funding. The study had no sponsorship.

Conflict of interest. The authors declare no conflict of interest.

Received: June 3, 2025
Accepted: July 7, 2025
Published: October 31, 2025

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