Visual Working Memory in Pediatric Epilepsy using Magnetoencephalography: Pilot Study

Pediatric epilepsy is known to impair behavior, cognition, and learning, particularly affecting working memory (WM). While many aspects of verbal WM have been studied in pediatric epilepsy, little is known about visuospatial working memory (VSWM). VSWM is crucial for spatial navigation, object recognition, and early literacy skills, aiding children in recalling shapes, colors, positions, and movements. Magnetoen-cephalography (MEG), a non-invasive neuroimaging technique with high temporal resolution, provides direct insight into the neural disruptions of VSWM. To investigate this, we measured brain activity using MEG in 10 children with drug-resistant epilepsy while performing a VSWM task. MEG data were processed with Brainstorm software, including source-reconstructed mapping and time-frequency decomposition. All participants successfully completed the VSWM task, yielding high-quality MEG time-frequency data and brain maps. Children achieved a mean task accuracy of 92.2% ± 16.6, with a mean reaction time (RT) of 725.1 ms ± 356.5 ms for correct responses. They responded faster in congruent trials (RT = 633 ms ± 278.8 ms) than incongruent trials (RT = 854.5 ms ± 553.3 ms). In this small sample and group level, children with right frontal focal epilepsy showed strong beta desynchronization during encoding, brief theta/alpha synchronization at the onset of maintenance, transient alpha/beta desynchronization mid-maintenance, and culminating in alpha/beta synchronization at the maintenance offset. Some differences in source activations were observed between the left and right frontal, parietal, and occipital regions.