Related Experiment Video
Updated: Aug 19, 2026
Using Eye-tracking to Assess the Relative Importance of Visual and Vestibular Input to Subcortical Motion Processing in the Roll Plane
Published on: August 22, 2025
Downbeat nystagmus as a result of lamotrigine toxicity
Ammar Alkawi1, Jorge C Kattah, Katie Wyman
1Department of Neurology, University of Illinois College of Medicine at Peoria, OSF Saint Francis Medical Center, 530N.E. Glen Oak Avenue, Peoria, IL 61637, USA. alkawi@uic.edu
Background:
Downbeat nystagmus (DBN) has been reported with phenytoin and carbamazepine toxicity. DBN has not been described as a result of lamotrigine toxicity.
Methods:
Clinical records, neuroimaging and video recordings were obtained in two patients diagnosed with intractable epilepsy who developed oscillopsia and incoordination while being treated with lamotrigine. One patient had a videonystagmographic (VNG) study.
Discussion:
Lamotrigine's half-life is extended when used with valproic acid; hence, the increased chance of neurotoxicity associated with DBN. In our cases, DBN and truncal ataxia occurred in conjunction with toxic lamotrigine serum levels.
Conclusion:
Anticonvulsant toxicity should be considered as a cause of DBN. Lamotrigine toxicity may be an unusual cause.
