Abstract
Antiepileptic drugs impair episodic memory in patients with epilepsy, but this effect has so far only been examined with tests that do not provide first-person experience—an aspect that is crucial for episodic memory. Virtual reality techniques facilitate the development of ecologically valid tests. In the present study, we measure the effect of antiepileptic drug changes in a within-subject design using a virtual reality test in order to provide direct evidence for effects of antiepileptic drugs on episodic memory. Among 106 recruited patients, 97 participated in a virtual reality test up to six times during a 4-day hospitalization, and 78 patients underwent changes in drug load during this period. There were six parallel versions of a virtual town test, with immediate recall and delayed recall after about 12 h. The test requires recall of elements, details, sequence of experience, and egocentric and allocentric spatial memory. We determined drug load by defined daily dose, and compared test performance at lowest antiepileptic drug load to highest antiepileptic drug load. Across the six towns, performance was lower in delayed compared to immediate recall. There was an overall effect of medication when comparing patients taking vs. not taking antiepileptic drugs and/or psychoactive drugs (p = 0.005). Furthermore, there was a within-subject effect of antiepileptic drug load (p = 0.01), indicating lower test performance at higher drug load. There was no effect of gender, daytime, circadian type, depression, seizures, lesions, and epilepsy. For patients with temporal lobe epilepsy, there was no effect of lateralization. The present study provides direct evidence for episodic memory impairment due to antiepileptic drugs, suggesting that a small change in drug load can matter. This study can serve as a proof of principle for the methodology, but a larger sample is needed to examine the differential effects of individual antiepileptic drugs.
Highlights
Memory complaints cause severe impairment of quality of life in patients with epilepsy [1,2,3]
We provided direct evidence that antiepileptic drug load negatively influences episodic memory in patients with epilepsy
Episodic memory performance was not determined by any other factor but age, especially not by epilepsy
Summary
Memory complaints cause severe impairment of quality of life in patients with epilepsy [1,2,3]. Antiepileptic drugs have effects on memory, but the nature and extent of the effect depends on the type of drug and on the domain of memory [4,5,6,7,8,9]. While the effect of antiepileptic drugs on semantic memory and executive functions has been very well examined [10, 11], only a. Drugs Affect Episodic Memory couple of studies have examined the effect of antiepileptic medication on episodic memory. The examination of drug effects on episodic memory deserves more attention. The main motivation for increasing scientific efforts in the documentation of drug effects is the demand from patients for a well-balanced tradeoff between optimal seizure control and minimal side effects. Only recently have scientists developed adequate means for examining episodic memory
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
