Researchers at the Johnson & Johnson Pharmaceutical Research & Development, New Jersey and Belgium, and University of California, Los Angeles, CA used the Cambridge Neuropsychological Test Automated Battery (CANTAB) and cognitive adverse events to evaluate neurocognitive effects of topiramate 100 mg/day vs placebo in 70 migraine patients aged 12 through 17 years. The CANTAB includes measures of object recognition, spatial memory span, paired associates learning, reaction time, sustained attention, and word fluency. Subjects responded to visually presented stimuli on a touch-sensitive screen. Slight statistically significant score increases in 3 CANTAB measures, indicating slowing of reaction time and processing, were associated with topiramate during double-blind treatment lasting 16 weeks. The most common adverse events included anorexia, insomnia, fatigue, and dizziness. Learning, memory, and executive function were unchanged. The tolerability profile of topiramate, including cognitive adverse events, appeared to be acceptable. 
COMMENT. An open-label study of the effectiveness of topiramate in 97 children with migraine found that the most common side effects were cognitive (12.5%), weight loss (5.6%), and paresthesia (2.8%) . A randomized, double-blind, placebo-controlled trial of topiramate in 162 children (age, 6-15 years) with migraine found 6.5% discontinued treatment because of side effects (URI infection, anorexia, weight decrease, gastroenteritis, paresthesia, and somnolence (Pearlman WP et al. Headache 2005;45:1304-1312). A review of 5 published reports of topiramate and migraine found the frequency of side effects varied considerably among studies, the most frequent being weight loss, anorexia, abdominal pain, difficulties in concentrating, sedation and paresthesia. It was concluded that the disability caused by the migraine should be assessed before initiating prophylactic treatment with potential side effects.