Posturography Sensitively Detects Abnormal Body Sway in Dizzy Patients with Therapeutic Blood Levels of Antiepileptics

Abstract

Posturography was conducted in four epileptic patients with blood antiepileptic drug (AED) levels within standard therapeutic ranges. Electronystagmograms (ENGs) were also recorded to examine any drug-induced oculomotor dysfunction. EEG, brain CT and MRI showed no specific abnormalities related to dizziness. However, posturography revealed an abnormal body sway, including increased area of sway and Romberg ratio, even when ataxia was not detected in routine neurologic examination. Posturography was abnormal only when the blood levels of phenytoin or carbamazepine were relatively elevated, and normalized when the blood levels decreased. The results indicated that the dizziness reflected mild, transient cerebellar ataxia related to AED doses. ENGs demonstrated no positive correlation between dizziness and oculomotor dysfunction. We conclude that posturography is clinically useful for quantitative evaluation of dizziness that may occur in epileptic patients on long-term AED treatment.