Paying attention to school achievement in childhood absence epilepsy.

Commentary Recent investigations of children with childhood absence epilepsy (CAE) have reliably demonstrated that CAE is not a syndrome free of cognitive or behavioral comorbidity. Particularly problematic is attentional impairment, not only because of attention's effects on cognitive and school performance but also due to its behavioral effects such as attention deficit hyperactivity syndrome (ADHD) (1). In the absence of clinical trials characterizing performance prior to treatment initiation , however, and evaluation of specific treatment risks from drugs or potential treatment benefit from EEG normalization, potential contributions to attention performance have not been independently characterized. Studies in adults have demonstrated that medications often used to treat CAE are also associated with differential risk of cognitive impairment (2). Further, potentially contributing to diminished attention are the effects of abnormal EEG discharges (3). Finally, the contributions of abnormal brain substrate giving rise to epilepsy versus AED treatment have been difficult to establish independent of the above factors (4). These issues are of considerable clinical and theoretical importance, not only to identify optimal CAE treatment associated with the least risk of cognitive side effects but ultimately to maximize school and vocational outcomes in these children. Cognitive testing is increasingly used as an outcome measure in clinical trials to characterize this important feature of treatment tolerability. Cognitive testing, however, is less frequently employed to categorize individual subject performance to characterize various treatment risks. The Con-ners' Continuous Performance Test (CPT), a classic approach assessing sustained attention in absence epilepsy beginning in the early 1960s (5), provides a measure that characterizes the likelihood that the individual's performance reflects clinically relevant attention impairment (i.e., Confidence Interval, or CI). By operationalizing individual CPT performance using Confidence Interval data in children completing the multi-center CAE trial (6), Masur and his colleagues define the frequency of attention impairment seen in children with CAE before, or within 1 week, of starting AED therapy. Using this clinically relevant criterion, over one-third of the 408 children (36%) demonstrated impaired attention function at study entry. OBJECTIVE: To determine the neurocognitive deficits associated with newly diagnosed untreated childhood absence epilepsy (CAE), develop a model describing the factorial structure of items measuring academic achievement and 3 neuropsychological constructs, and determine short-term differential neuropsychological effects on attention among ethosuximide, valproic acid, and lamotrigine. METHODS: Subjects with newly diagnosed CAE entering a double-blind, randomized controlled clinical trial had neuropsychological testing including assessments of general intellectual functioning , attention, …