1. Dementia-Related Epilepsy in Vascular Dementia and Alzheimer’s Disease
Tyler Webb, MD; David Thompson, PhD; Summer Frank; Jennifer Lippoldt, MPH; Linda Hershey, MD
Department of Neurology, University of Oklahoma Medical Center; Oklahoma City, OK
METHODS
This study consisted of a two-year, retrospective review of 195 charts of patients with varying dementia diagnoses, including vascular dementia (VaD), Alzheimer’s disease (AD), dementia with Lewy bodies (DLB), and the various tauopathies (Tau). The tauopathies were grouped into one category due to the relatively low number of patients with these diagnoses and included progressive supranuclear palsy, frontotemporal dementia and corticobasal degeneration. The patients’ ages were years, and the diagnosis of epilepsy (if present) was within 5 years of the onset of dementia. Two Mini Mental Status Exam (MMSE) scores separated by greater than 9 months were used to estimate the progression of dementia and were adjusted for time from dementia diagnosis.
OBJECTIVE
We asked whether epilepsy was more common in patients with vascular dementia, Alzheimer’s disease, or other dementia subtypes. We also asked whether those with dementia-related epilepsy exhibited a more rapidly progressive course than those who were seizure-free, and if epilepsy developed earlier in the course of vascular dementia.
BACKGROUND
Seizures have a well-known and well-documented association with Alzheimer's disease when compared to age-matched controls. However the association, or lack thereof, between seizures and other neurodegenerative diseases has not been as clearly elucidated. We were particularly interested in the observation that seizures seem to be more common among those with vascular dementia and that they seemed to develop epilepsy earlier in the course of their disease. In a retrospective chart review of patients with multiple dementia types we looked at the prevalence of the comorbid diagnosis of epilepsy. We also studied when in the course of their disease the seizures developed and how the presence of epilepsy altered the progression of their dementia.
Fig. 2 Decline of MMSE scores after a minimum of 9- month follow-up among those with and without epilepsy revealed a significantly more rapid decline in the epilepsy group
Fig. 3 Time to event curves showing a shorter time course of dementing illness before the development of seizures among those patients with vascular dementia compared with those who had Alzheimer’s disease
% of dementia Patients
RESULTS
The prevalence of epilepsy [fig. 1] in VaD (20.0%; exact binomial 95%CI: 7.7%, 38.6%) did not differ significantly compared to that seen in AD (2.9%; exact binomial 95%CI: 0.6%, 8.3%). Patients with dementia-related epilepsy exhibited a significantly more rapid decline of MMSE scores (1.75 points/year with 95% CI: 0.59, 2.91), compared to the seizure-free group (0.51 points/year with 95% CI: 0.22, 0.80) [fig. 2]. Time to event curves among those with and without epilepsy showed that patients with VaD developed epilepsy earlier than those with AD (logrank test p=0.0022) [fig. 3].
Fig. 1 The prevalence of epilepsy categorized by dementia type did not differ significantly between each group. Confidence intervals are shown in red and are based on a CI of 95%.
Conclusion: Epilepsy prevalence does not differ significantly among various dementia subtypes, but those with VaD develop epilepsy earlier than those with AD. Patients with dementia-related epilepsy have a more rapid decline than those who are seizure-free.
Last Edited: September 2, 2013
Author Disclosures: none