Deep brain stimulation continues to show promise for patients with mild Alzheimer’s disease

Forty-two patients with mild Alzheimer's disease were enrolled in a randomized, double-blind multicentre phase II 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. To better measure the impact of electrical stimulation in the brain, patients were then randomly assigned to either the "on" or "off" stimulation group and monitored for the 12 months following their procedure. Once the trial follow up was complete, all patients then had their electrodes turned on.

Results from the trial showed that DBS stimulation of the fornix (DBS-f) continues to be safe and that, although overall there were no differences in cognitive outcomes between the "on" and "off" study participants, those 65 years of age and older appeared to experience slower cognitive decline as a result of the treatment.

Another finding of interest was that the brain's ability to metabolize glucose increased over the year-long study period in patients receiving electrical stimulation, indicating that the brain networks made dysfunctional by Alzheimer's improved in some ways.

"We are encouraged by these findings as they indicate we are headed in the right direction with our research on DBS as a treatment for Alzheimer's disease," says Dr. Andres Lozano, neurosurgeon and the lead author of the study. "We now have a better idea of which patients will benefit most from this treatment and how the stimulation might slow the progression of Alzheimer's."

"The next phase of our research will focus on determining what stimulation dosage will have the most impact against this disease," adds Lozano who is also University Professor and Chairman, Department of Neurosurgery, University of Toronto.

The findings were published in the Journal of Alzheimer's Disease and will be used for the recruitment of a phase III clinical trial to refine the patient criteria.