Dissertation August 29, 2024 New PhD from ERGO – candidate Helle Herrman
Helle Herrman defended her thesis “Deep brain stimulation to the anterior thalamic nuclei in refractory epilepsy” for the degree of PhD at the University of Oslo. She is now working as a Senior Consultant in Department of neurology at Oslo university hospital.
The committee consisted of professor Anna Sabers, Rigshospitalet university hospital, Copenhagen, Denmark, as first opponent, Ass. Professor Geir Bråthen, St. Olav’s hospital, Trondheim, Norway as second opponent and professor Angelika Sorteberg, Oslo university hospital, Norway as third opponent and head of the committee.
Supervisors were professors Espen Dietrichs and Erik Taubøll, Department of Neurology, Oslo university hospital.
Summary of the thesis
Deep brain stimulation to the anterior thalamic nuclei in refractory epilepsy
Norway has about 35000 people with epilepsy. Around 30% are not seizure free on drug therapy or after resective neurosurgery. Other treatment options are needed. In deep brain stimulation thin electrodes are implanted and brain activity altered through low current electrical pulses. This is established treatment against tremor and Parkinson’s Disease. More recent research indicates that deep brain stimulation may also inhibit epileptic seizures. We have therefore studied the effect and security of such treatment.
18 people with treatment refractory epilepsy were implanted with electrodes for deep brain stimulation. Stimulation was started immediately after the operation in one half of the patients. After six months stimulation was turned on also in the remaining patients. The study was double blinded. Neither the patients nor the treating neurologist knew which patients where on active stimulation during the first six months.
We found no significant differences between the two groups after six months. After six months of active stimulation also in the second group, we found that all 18 patients had a significant 22% improvement in seizure frequency after six months of deep brain stimulation.
We originally planned to include 40 patients. Study inclusion was stopped prematurely since a halfway analysis revealed that results were not as good as expected.
The study showed a moderately improved seizure frequency. The operation procedure and deep brain stimulation were well tolerated. Higher mental functions like language, memory and executive functions were not affected, and we found no psychiatric adverse effects like anxiety or depression.
We performed an extra study method review since our results were not as good as expected. A slightly different procedure for placing the electrodes will probably improve accuracy and help finding the best target for deep brain stimulation in epilepsy.
More and larger studies are needed to decide the place for deep brain stimulation in the treatment of epilepsy in Norway.
