Promise of Deep Brain Stimulation

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Study suggests deep brain stimulation could be treatment for mild late-onset Alzheimer disease.
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The study was co-led by Dr. Andres Lozano, a Senior Scientist at the Krembil Research Institute.

An age group analysis of data from the ADvance trial has shown that participants with Alzheimer disease over the age of 65 continue to derive the most benefit from deep brain stimulation of the fornix (DBS-f).

These findings are the potential beginnings of a patient profile for DBS-f treatment for Alzheimer disease. They were published on June 19 in the Journal of Alzheimer's Disease by a team of researchers co-led by Dr. Andres Lozano, a neurosurgeon at Toronto Western Hospital and a Senior Scientist at the Krembil Research Institute.

To further explore the benefits for this demographic, the research team is soon launching a phase 3, multicentre international trial that will study the effects of DBS-f in 140 patients over the age 65.

"We are encouraged by these findings as they continue to help us identify who will benefit most from DBS to treat Alzheimer disease and learn more about this illness," says Dr. Lozano. "With so few treatments available and the incidence of Alzheimer's only expected to increase, we really need to fully explore all treatments that seem to be of benefit to patients."

These latest results were captured from the second year of data of the ADvance trial whose first-year data was published in 2016. In that trial, 42 patients with mild Alzheimer disease were enrolled in a randomized, double-blind multicentre phase 2 clinical trial and implanted with DBS electrodes directed at the fornix—a bundle of nerve fibres in the brain that carry signals from the hippocampus—and followed for a total of two years.

In the first 12 months of the trial, to better measure the impact of electrical stimulation in the brain, patients were randomly assigned to either the "on" or "off" stimulation group after their procedure and monitored. Once this phase of follow up was complete, all patients then had their electrodes turned on and were followed for another 12 months.

In the second 12-month phase, researchers noted similar observations they had seen in the first phase: that, although there were no differences overall in cognitive outcomes between study participants who had their device turned on right after surgery and those who had it turned on after 12 months, those 65 years of age and older appeared to experience a slower progression of Alzheimer disease than those under that age, regardless of when their device was turned on.

"The next phase of our research will help determine whether this observed benefit is something we continue to see in this age group," says Lozano. "If it does, this could potentially give us a treatment for mild, late-onset Alzheimer disease."

This is an adaptation of a story originally published by UHN News on www.uhn.ca.