Neurophysiological signatures reflect differences in visual attention during absence seizures

Objective: Absences affect visual attention and eye movements variably. Here, we explore whether the dissimilarity of these symptoms during absences is reflected in differences in electroencephalographic (EEG) features, functional connectivity, and activation of the frontal eye field. Methods: Pediatric patients with absences performed a computerized choice reaction time task, with simultaneous recording of EEG and eye-tracking. We quantified visual attention and eye movements with reaction times, response correctness, and EEG features. Finally, we studied brain networks involved in the generation and propagation of seizures. Results: Ten pediatric patients had absences during the measurement. Five patients had preserved eye movements (preserved group) and five patients showed disrupted eye movements (unpreserved group) during seizures. Source reconstruction showed a stronger involvement of the right frontal eye field during absences in the unpreserved group than in the preserved group (dipole fraction 1.02% and 0.34%, respectively, p &lt; 0.05). Graph analysis revealed different connection fractions of specific channels. Conclusions: The impairment of visual attention varies among patients with absences and is associated with differences in EEG features, network activation, and involvement of the right frontal eye field. Significance: Assessing the visual attention of patients with absences can be usefully employed in clinical practice for tailored advice to the individual patient.</p

The cognitive profile of ethosuximide in children

\u3cp\u3eIntroduction: Although ethosuximide is one of the oldest antiepileptic drugs (AEDs), little information is available about the cognitive side effects of ethosuximide. Objective: The aim of this study was to investigate the cognitive profile of ethosuximide. Methods: In this cross-sectional study, we used an extensive neuropsychological test battery in patients with epilepsy aged 6–16 years who were treated with monotherapy ethosuximide. We evaluated the efficacy of the drug by seizure frequency (seizure free or not). Results: We included 61 patients with a mean age of 9.4 years [standard deviation (SD) 2.7] who used on average 686 mg/day (SD 245) ESM as monotherapy. ESM was effective in the majority of the patients (70 % were seizure free for at least 6 months at moment of inclusion). The total study population showed impairments of intelligence, visuomotor, and attentional function including activation/alertness. Comparisons between the well-controlled patients and patients who were not in remission showed significantly lower intelligence values and lower performance on the visual-perceptual and attentional tasks for the group with ongoing seizures. Our results suggested that the higher order cognitive dysfunctions (such as intelligence and visual-perceptual functions) may be regarded as seizure or aetiology effects and that the impaired fluid cognitive functions, such as activation/alertness, sustained auditory attention and attentional control or switching, were due to ESM. Conclusion: This study suggests the attentional dysfunction resulting in psychomotor slowing and alertness deficits may be regarded as effects of ethosuximide. Although no untreated baseline assessment was available, these effects are comparable to those of other AEDs, and ethosuximide may therefore be considered an AED with only mild effects on cognition. As ethosuximide is a first-line therapy for absence seizures in childhood, and drug-induced cognitive impairment may interfere with development, learning, and academic achievement, these findings are of interest to clinicians who prescribe this drug, especially when informing parents.\u3c/p\u3

The Cognitive Profile of Ethosuximide in Children

Introduction: Although ethosuximide is one of the oldest antiepileptic drugs (AEDs), little information is available about the cognitive side effects of ethosuximide. Objective: The aim of this study was to investigate the cognitive profile of ethosuximide. Methods: In this cross-sectional study, we used an extensive neuropsychological test battery in patients with epilepsy aged 6–16 years who were treated with monotherapy ethosuximide. We evaluated the efficacy of the drug by seizure frequency (seizure free or not). Results: We included 61 patients with a mean age of 9.4 years [standard deviation (SD) 2.7] who used on average 686 mg/day (SD 245) ESM as monotherapy. ESM was effective in the majority of the patients (70 % were seizure free for at least 6 months at moment of inclusion). The total study population showed impairments of intelligence, visuomotor, and attentional function including activation/alertness. Comparisons between the well-controlled patients and patients who were not in remission showed significantly lower intelligence values and lower performance on the visual-perceptual and attentional tasks for the group with ongoing seizures. Our results suggested that the higher order cognitive dysfunctions (such as intelligence and visual-perceptual functions) may be regarded as seizure or aetiology effects and that the impaired fluid cognitive functions, such as activation/alertness, sustained auditory attention and attentional control or switching, were due to ESM. Conclusion: This study suggests the attentional dysfunction resulting in psychomotor slowing and alertness deficits may be regarded as effects of ethosuximide. Although no untreated baseline assessment was available, these effects are comparable to those of other AEDs, and ethosuximide may therefore be considered an AED with only mild effects on cognition. As ethosuximide is a first-line therapy for absence seizures in childhood, and drug-induced cognitive impairment may interfere with development, learning, and academic achievement, these findings are of interest to clinicians who prescribe this drug, especially when informing parents

Lower myelin-water content of the frontal lobe in childhood absence epilepsy

\u3cp\u3eObjective: The frontal lobe in childhood absence epilepsy (CAE) might be affected due to the suggested involvement of the frontal lobe during absence seizures and reports on attentional deficits. Previously, subtle white matter abnormalities have been reported in CAE. However, the impact of one of the most characteristic components of the white matter, the myelin content, remains underdetermined. Therefore, this study investigated whether the myelin content in frontal areas is adversely affected in CAE compared to controls. Methods: Seventeen children with childhood absence epilepsy (mean age ± standard deviation [SD], 9.2 ± 2.1 years) and 15 age- and sex-matched controls (mean age ± SD, 9.8 ± 1.8 years) underwent neuropsychological assessment and a magnetic resonance imaging (MRI) examination. T2 relaxometry scans were used to distinguish myelin-water from tissue water and to determine the myelin-water fraction (MWF) in the frontal, temporal, parietal, occipital, and insular lobes. A linear regression model including age and sex as covariates was used to investigate group differences. Furthermore, the relationship of MWF with cognitive performance and epilepsy characteristics was determined. Results: The frontal lobe revealed a significantly lower myelin-water content in children with CAE compared to controls over the developmental age range of 6-12 years (5.7 ± 1.0% vs 6.6 ± 1.1%, P = 0.02). This association was not found for any of the other four lobes (P &gt; 0.10). No significant relation was found between myelin-water content and cognitive performance or epilepsy characteristics. Significance: The lower frontal myelin-water content of children with CAE in comparison with healthy controls probably reflects an altered neurodevelopmental aspect in CAE, of which the underlying mechanisms still need to be unraveled.\u3c/p\u3