BOSTON—Researchers have found a linkage between multiple seizures and heart function that can lead to Sudden Unexplained Death in Epilepsy Patients (SUDEP).
In animal models stimulated to represent refractory epilepsy in humans, investigators at the University of Utah found that repeated seizures produce alterations in cardiac electrical activity predictive of sudden cardiac death. The study animals having multiple seizures also had increased susceptibility to experimentally induced ventricular arrhythmias, compared with animals exposed to initial kindling only.
“Our findings support the hypothesis that multiple seizures produce progressive, chronic effects that could culminate in sudden death,” said Steve Bealer, PhD, who is a Professor of Pharmacology and Toxicology at the University of Utah in Salt Lake City.
About one in 150 persons with uncontrolled seizures experiences SUDEP, according to the researchers.
In 2008, the American Epilepsy Society and the Epilepsy Foundation released a report and recommendations for better scientific understanding and prevention of SUDEP. Among the key findings in that report are the low autopsy rate in suspected SUDEP cases and the incompleteness of autopsy information.
To address these problems, the authors of the report recommend the development of uniform criteria for SUDEP determination, including protocols for complete autopsy examination, and an awareness campaign aimed at affected families, coroners, and medical examiners regarding the need for complete autopsy examinations in suspected cases.
NeuroPace System Reduces Seizures in Patients With Epilepsy
Researchers reported that the RNS System, a novel investigational device that uses responsive brain neurostimulation, significantly reduced the frequency of seizures in a study of 191 patients with medically intractable partial-onset epilepsy.
The RNS System is designed to continuously monitor brain electrical activity and, after identifying a patient’s unique “signature” indicating a seizure is starting, deliver brief and mild electrical stimulations with the intention of suppressing the seizure. NeuroPace, Inc (Mountain View, California) plans to submit a premarket approval application to the US FDA in early 2010 regarding the RNS System for the treatment of epilepsy.
“For people who cannot control their seizures effectively with medication, the data show the RNS System may be a safe and effective treatment option,” said Martha Morrell, MD, Chief Medical Officer of NeuroPace, Inc. and Clinical Professor of Neurology at Stanford University in California. “The results also indicate that the device became even more effective over time. These findings, drawn from a data set that includes people living with the most difficult type of epilepsy to manage, truly speak to the potential of responsive neurostimulation in controlling seizures.”
The trial demonstrated a statistically significant reduction in seizure frequency in the treatment group (responsive stimulation active), as compared with the sham stimulation group (responsive stimulation inactive). During the last two months of the three-month blinded evaluation period, people in the treatment group experienced a mean percentage reduction of 29% in their disabling seizures, compared with a 14% reduction for those in the sham stimulation group. In the long-term, open-label period of the trial, at least 12 weeks of data were available for 171 study participants; 47% of these subjects experienced a 50% or greater reduction in their seizure frequency based on their most recent 12 weeks of data, as compared with their baseline rate.
The trial also demonstrated a serious adverse event rate that was less than that for comparative surgical procedures. No serious unanticipated device-related adverse events were reported, and there was no difference between the treatment and sham stimulation groups when comparing the rate of adverse events, including depression, memory impairment, and anxiety.
Pediatric Research Focuses on Quality of Life, Comorbities
Three studies reported that it is possible for children with epilepsy to have a quality of life similar to that of other children or to at least have their lives improved if given optimal care.
In one longitudinal study of 374 families in Canada, health-related quality of life data were obtained for children ages 4 to 12 with new-onset epilepsy. Child health questionnaires were completed by the parents postdiagnosis, and six, 12, and 24 months later. The multicenter study of patients treated by 53 pediatric neurologists found that although health-related quality of life was compromised initially postdiagnosis, it improved significantly during the next two years to levels close to those reported for healthy children.
A second study addressed children with epilepsy who experience absence seizures, episodes lasting three to 10 seconds that cause impaired consciousness. The disorder not only affects children during their seizures, but between seizures as well, causing marked between-seizure deficits in attention and social functioning. In a study conducted at the Yale University School of Medicine in New Haven, Connecticut, researchers administered a Continuous Performance Attention Task (CPT) to 34 children ages 7 to 18 to examine attention between seizure episodes. The investigators found that children with absence seizures made more errors during the CPT than did normal controls. Using fMRI, the research team also was able to identify differences in the way children with absence epilepsy use brain networks involved in attention, taking a step forward in explaining the between-seizure deficits in attention in children with absence epilepsy.