White, gray matter MRI abnormalities linked to risk for late-onset epilepsy

Key takeaways:

• The study analyzed data from 1,224 individuals without and 27 individuals with late-onset epilepsy.
• Those with seizures in late-onset epilepsy had greater white and gray matter abnormalities prior to the seizures.

PHILADELPHIA — In older adults, the presence of white and gray matter abnormalities on MRI is linked to greater risk for late-onset epilepsy, according to a poster presentation.

“We used an MRI done before epilepsy diagnosis to ask a question: ‘Are there features on the MRI that can predict who will develop late-onset epilepsy?’,” James J. Gugger, MD, PharmD, assistant professor of neurology at the Hospital of the University of Pennsylvania, told Healio at the American Neurological Association annual meeting.

Gugger and colleagues sought to determine the association between structural brain MRI abnormalities and incident epilepsy in older adults.

Their study drew data from the Atherosclerosis Risk in Communities (ARIC) study of adults aged 45 to 64 years who were admitted to the study from 1987 to 1989 and followed through 2018. From ARIC hospitalization records and Medicare claims data among 1,961 participants, the researchers identified 1,251 individuals for analysis, among them 27 cases of late-onset epilepsy (LOE) beginning at age 67 or later (mean age 75 years; 48.1% female), and 1,224 individuals without LOE (mean age 76 years; 60.5% female). Using 3T structural brain MRI scans acquired between 2011 and 2013, researchers evaluated the relative pattern of grey matter abnormalities (ie, cortical thinning and reduced subcortical volume) and white matter microstructural integrity among participants who developed LOE after MRI in comparison with participants without seizures.

Cox proportional hazards regression was utilized to examine the association between the number of abnormal brain regions and incident LOE, with the number of abnormalities dichotomized as either high or low based on median split. All models were adjusted for demographics, hypertension, diabetes, smoking, stroke and dementia status.

Gugger and colleagues reported that 27 individuals developed LOE after MRI over a median of 6.4 years of follow-up. Participants with incident LOE after MRI demonstrated significantly higher levels of cortical thinning and white matter microstructural abnormalities, present prior to seizure onset, compared with those without seizures.

Data further showed a greater number of abnormalities associated with incident LOE after controlling for demographic factors and health risk factors such as cardiovascular disease, stroke and dementia (grey matter: HR = 2.3; 95% CI, 1-5; white matter diffusivity: HR = 3.2; 95% CI, 1.3-7.7).

“We found more white matter abnormalities than gray matter abnormalities, which is surprising since epilepsy is thought of as a cortical, gray matter disease,” Gugger told Healio. “It’s conceivable that this white matter injury, in certain people, disconnects certain connections.”