Abstracts

The relative cognitive and neurophysiological effects of levetiracetam (LEV) and carbamazepine (CBZ) are uncertain., This study compared the effects of LEV and CBZ using a randomized, double-blind, two-period crossover design in healthy adults. Mean (SD) maintenance doses and blood levels were: LEV mean dose = 2000mg/day (0), LEV mean blood level = 32 mcg/ml (11); CBZ adjusted by blood level to a mean dose = 564 mg (110); CBZ mean blood level = 7.5 mcg/ml (1.5). The results of the primary outcome measures (i.e., 33 variables from 11 standard neuropsychological tests) have been previously reported in abstract form. In this abstract, we report the results of a cognitive neurophysiological test (CNT) of working- and episodic memory which included measures of EEG/EP, cognitive performance, and subjective effects (22 variables). Testing was done at screening, baseline pre-drug treatment, end of each maintenance phase (4 weeks), and end of each washout period after drug treatment., 28 adults (mean age = 33; range = 18-51 years) completed the study. Relative to LEV and non-drug, CBZ produced both subjective and cognitive performance impairments. In addition, CBZ produced an increase in low frequency ([lt] 10Hz) EEG power and changes in ERP measures. Linear discriminant analysis revealed 100% sensitivity and specificity for detection of CBZ relative to either LEV or non-drug conditions using EEG neurophysiological measures; detection was less accurate when using neuropsychological variables from the CNT or from the original full neuropsychological battery., CBZ produces more untoward neuropsychological and neurophysiological effects than does LEV at the dosages and timeframes employed in this study. EEG neurophysiological measures improve detection of these effects., (Supported by: The cognitive neurophysiological component of this study was supported by a grant from the National Institute of Neurological Diseases and Strokes to Dr. Gevins. The drug administration and neuropsych testing was supported by a grant from UCB Pharma to Dr. Meador.)