Assessment of Antiepileptic Drug Related Neurotoxicity: Quantitative EEG Measures and Cognitive Tests
Abstract number :
3.104
Submission category :
Year :
2001
Submission ID :
3088
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
M.C. Salinsky, MD, Neurology, Oregon Health Sciences University, Portland, OR; B.S. Oken, MD, Neurology, Oregon Health Sciences University, Portland, OR; D. Storzbach, PhD, Psychiatry, Portland VAMC, Portland, OR; L.M. Binder, PhD, Neurology, Oregon Healt
RATIONALE: Antiepileptic drugs (AEDs) can be associated with neurotoxic side effects including cognitive dysfunction. Objective determination of neurotoxicity in individual patients is problematic. We evaluated quantitative EEG as a measure of AED related neurotoxicity.
METHODS: Subjects included 20 patients beginning AED therapy (Eon)and 12 patients stopping AED therapy after a long seizure free interval(Eoff). All subjects underwent structured EEG recording for quantitative analysis and a cognitive test battery, prior to starting/stopping AEDs (baseline) and again 12-16 weeks later, at least four weeks after the last dose change. Two control groups were studied; 24 epilepsy patients on stable AED therapy (Eco), and 62 healthy controls who were not taking any CNS active drugs (Nco). The control subjects were also tested twice over a 12-16 week interval. EEG test-retest analysis was limited to the averaged occipital channels. Four measures (peak frequency of the posterior rhythm, median frequency, percent theta power, percent delta power) were analyzed. EEG and cognitive test changes over 12-16 weeks were scored using test-retest regression equations derived from the Nco subjects. Wilcoxon tests were used for two-group comparisons.
RESULTS: Eon[ssquote]s had a significant decrease, and Eoff[ssquote]s a significant increase in the peak frequency measure as compared to Eco or Nco subjects (median change -0.45, 0.48, -0.07, and -0.05 Hz for the Eon, Eoff, Eco, and Nco groups respectively). Results for median frequency and percent theta power were similar. Change in peak frequency correlated with a summary cognitive change measure (r=0.71), and several individual cognitive test measures. 22 of 32 Eon/Eoff patients (and 1 of 24 Eco subjects) exceeded the 95% confidence interval for change in peak frequency, as opposed to a maximum of 7 patients for any cognitive measure.
CONCLUSIONS: Quantitative measures derived from the EEG are sensitive to AEDs, correlate with AED related cognitive effects, and are more sensitive than cognitive tests in detecting significant changes in individual patients. EEG may be a practical measure of AED related neurotoxicity.
Support: Supported by a grant from the U.S. Department of Veterans Affairs