Balance and reaction time do not rapidly improve off antiseizure drugs

People with epilepsy (PWE) exercise less than the general population and describe a lower level of fitness. Exercise improves comorbidities associated with epilepsy and may help seizure control. We aimed to record balance and reaction time in patients undergoing antiseizure drug (ASD) taper in the epilepsy monitoring unit (EMU) to determine if there is a reversible, dose-dependent effect of these medications.

We tested 21 patients and 21 controls using a Wii Balance Board (WBB) and online reaction time test. The patients were recruited during an EMU stay and were tested before and after medication taper. Drug levels were also checked. Sway from center of pressure (COP) and speed of sway were tested with eyes open on two legs, eyes closed on two legs, and eyes open on one leg. Reaction time was tested.

Compared with controls, patients on ASDs had more sway from COP (with eyes open on two legs: p = 0.0022 in the anterior-posterior axis and p = 0.022 in the medial-lateral axis using linear regression) and worse reaction time (p < 0.001 using linear regression, adjusted for age and gender). There was no difference in reaction time or sway from COP between trials 1 and 2, before and after stopping ASDs (p = 0.2 using a paired t test for reaction time and p = 0.08 using a paired t test for speed of sway with eyes closed). There was no relationship between time since last seizure or duration of seizures and balance or reaction time.

Balance and reaction time in patients on ASD is impaired compared with controls. There is no immediate improvement in these measures following ASD withdrawal. This difference may result from vestibular or cerebellar effects. More research is needed to determine the individual effects of particular medications on balance and reaction time.