PHILADELPHIA—Electrodermal (EDA) biofeedback, a method that uses electrodes to detect changes in the skin’s electrical activity, effectively reduces seizure frequency in patients with drug-resistant epilepsy, according to data presented at the 69th Annual Meeting of the American Epilepsy Society.
In previous research, Yoko Nagai, PhD, Wellcome Trust Research Fellow at Brighton and Sussex Medical School in the United Kingdom, and colleagues found that increased skin conductance reduces excitability in the motor cortex in patients with epilepsy. Certain antiepileptic drugs also produce this effect. The investigators also concluded that skin conductance is associated with regional changes in brain activity.
In the current study, Dr. Nagai and colleagues enrolled eight participants with temporal lobe epilepsy into a clinical trial. The patients received EDA biofeedback training three times per week for four weeks and underwent 1.5-T fMRI scans at the first and last training sessions. The researchers conducted seed-based analysis with the ventromedial prefrontal cortex/orbitofrontal cortex.
Biofeedback significantly reduced the patients’ seizure frequency after a month of training. The investigators observed the reduction in all patients, and the average reduction of seizure frequency was 39.6%. “For some patients, the effect happens after a week or two weeks,” said Dr. Nagai. “The most important thing is to detect very early signs of seizures, then apply the skills, and the seizure doesn’t happen,” she added.
The researchers found increases in functional connectivity between the seed ventromedial prefrontal cortex/orbitofrontal cortex region and the inferior temporal gyrus, anterior cingulate, putamen, and precentral gyrus. These regions of the brain are responsible for emotional arousal and control of the motor cortex. In contrast, the investigators noted decreased connectivity with the superior temporal gyrus and angular gyrus.
The study’s small patient population results in part from the fact that Dr. Nagai is the only researcher who is studying this technique in the UK. “I want to put it in a digital form so that we can offer it to many more patients,” she said. “The next study, after this is completed, will be 400 to 500 patients.” Previous research indicates that once patients have learned the skills, they can use the technique for years afterward.
“Our findings suggest that EDA biofeedback is an accessible, nonpharmacologic, and side effect-free treatment for patients with drug-resistant epilepsy,” said Dr. Nagai. “We show a characteristic shift in resting state network organization that is consistent with a treatment-related enhancement in connectivity between regions implicated in affective arousal and cortical control. Our neuroimaging study provides insight into potential mechanisms underlying the efficacy and validity of EDA biofeedback treatment for epilepsy.”
—Erik Greb
