SAN DIEGO – Brainstem volume loss is extensive in sudden unexplained death in epilepsy, suggesting that loss of brainstem volume on MRI might predict who is at risk, according to investigators from the Center for SUDEP Research, a multicenter research collaborative.
The “MRI can detect potentially life threatening brainstem damage before SUDEP [sudden unexplained death in epilepsy] onset and ought to be further studied as a clinically useful biomarker to identify patients at risk for SUDEP,” said lead investigator Alica Goldman, MD, PhD, associate professor of neurology and neurophysiology at Baylor College of Medicine, Houston, and an investigator for the research collaborative.
Dr. Alica Goldman
SUDEP is the leading cause of death in patients with focal epilepsy, but there’s no way at the moment to know who is at risk. The goal of the work is to identify patients ahead of time, and intervene to alleviate the risk, perhaps with tighter seizure control.
It’s possible SUDEP is due to autonomic failure secondary to damage to areas of the brainstem that control autonomic functions such as breathing and heartbeat. Cardiorespiratory failure has been reported in cases of witnessed SUDEP, and the team previously reported structural mesencephalic and lower brainstem abnormalities in two SUDEP cases with temporal lobe epilepsy (Neuroimage Clin. 2014 Jul 9;5:208-16).
“It was a logical transition to have a larger study,” Dr. Goldman said at the annual meeting of the American Neurological Association.
The team compared findings from standardized 3T MRI exams in 18 patients with focal-onset epilepsy, 27 SUDEP cases that had focal-onset epilepsy and one or more MRIs within 10 years of death, and 11 controls without epilepsy.
They also looked at heart rate variability based on ECG readings, a proxy of autonomic control. Abnormal variability is a risk factor for arrhythmias and sudden cardiac death, and has been shown previously to correlate with epilepsy duration and frequency. It also seems worse at night, when SUDEP risk is highest.
In the living epilepsy patients, the team found structural volume loss in the dorsal mesencephalon and other brainstem areas, and the loss correlated with abnormal heart rate variability (P less than .001).
In the SUDEP cases, “we found that patients who died from SUDEP had widespread brainstem volume loss in their last MRI before death, and the extent of volume loss in the brainstem correlated with shorter survival time” from the final MRI (P = .03).
The SUDEP cases were a mean of 23 years old at their last MRI; the majority of the cases were men.
The National Institutes of Health and the Epilepsy Foundation supported the work. Dr. Goldman had no relevant disclosures.