Neural correlates of verbal working memory in children with epilepsy with centro-temporal spikes.
BACKGROUND
Previous functional magnetic resonance imaging (fMRI) studies have identified brain systems underlying different components of working memory (WM) in healthy subjects. The aim of this study was to compare the functional integrity of these neural networks in children with self-limited childhood epilepsy with centro-temporal spikes (ECTS) as compared to healthy controls, using a verbal working memory task (WMT).


METHODS
Functional MRI of WM in seventeen 6-to-13 year-old children, diagnosed with ECTS, and 17 sex- and age-matched healthy controls were conducted at 3 T. To estimate BOLD responses during the maintenance of low, medium, and high WMT loads, we used a Sternberg verbal WMT. Neuropsychological testing prior to scanning and behavioral data during scanning were also acquired.


RESULTS
Behavioral performances during WMT, in particular accuracy and response time, were poorer in children with ECTS than in controls. Increased WM load was associated with increased BOLD signal in all subjects, with significant clusters detected in frontal and parietal regions, predominantly in the left hemisphere. However, under the high load condition, patients showed reduced activation in the frontal, temporal and parietal regions as compared to controls. In brain regions where WM-triggered BOLD activation differed between groups, this activation correlated with neuropsychological performances in healthy controls but not in patients with ECTS, further suggesting WM network dysfunction in the latter.


CONCLUSION
Children with ECTS differ from healthy controls in how they control WM processes during tasks with increasing difficulty level, notably for high WM load where patients demonstrate both reduced BOLD activation and behavioral performances.
['Ciumas|Carolina|C|', 'Montavont|Alexandra|A|', 'Ilski|Faustine|F|', 'Laurent|Agathe|A|', 'Saignavongs|Mani|M|', 'Lachaux|Jean-Philippe|JP|', 'de Bellescize|Julitta|J|', 'Panagiotakaki|Eleni|E|', 'Ostrowsky-Coste|Karine|K|', 'Herbillon|Vania|V|', 'Ibarrola|Danielle|D|', 'Hermier|Marc|M|', 'Arzimanoglou|Alexis|A|', 'Ryvlin|Philippe|P|']
D001921:Brain D001931:Brain Mapping D002648:Child D004827:Epilepsy D006801:Humans D008279:Magnetic Resonance Imaging D008570:Memory, Short-Term D009483:Neuropsychological Tests
Verbal Working memory Children with epilepsy fMRI BCECTS Rolandic epilepsy