Approximately 6.5 million Americans sixty-five years old and over are currently living with Alzheimer’s disease (AD) in 2022– making it one of the most common causes of dementia.
Yet, despite the disease’s prevalence, AD is still not easy to prevent or treat.
In Germany, though, one interesting therapy known as deep brain stimulation (DBS) has already been approved for treating a range of neurological movement disorders– including dystonia and Parkinson’s disease, as well as neuropsychiatric diseases like obsessive-compulsive disorder (OCD).
And recently, a research team from the Charité – Universitatmedizin in Berlin, one of the largest university hospitals in Europe, has found that stimulating a specific neural network via DBS may reduce symptoms among Alzheimer’s patients.
Through the DBS technique, doctors implant very thin electrodes into a patient’s brain– which allows for mild electrical pulses to be constantly delivered to distinct brain regions.
The implants do remain permanently in the brain and are connected via wires to another device– similar to a pacemaker– that is implanted under the skin in the chest region.
This secondary device ultimately regulates and adjusts the frequency and strength of electrical brain stimulation.
Now, even though DBS has been used as an established Parkinson’s disease treatment for two decades at this point– with costs covered by health insurance providers– the therapy is still not entirely well-known, according to Professor Andreas Horn, head of a network-based brain stimulation lab at the Department of Neurology and Experimental Neurology.
So, interestingly, the launching point for this Charité study was actually an unexpected observation made during a different Canadian study.
Ocskay Mark – stock.adobe.com – illustrative purposes only, not the actual people
“In one patient, who was being treated for obesity, deep brain stimulation caused flashbacks– sudden memories of their childhood and adolescence,” explained Dr. Ana Sofía Ríos, the study’s lead author.
“This led the Canadian researchers to suspect that stimulating this brain region, which was located in the fornix, might also be suitable for treating Alzheimer’s.”
Afterward, scientists from seven international institutions began collaborating on this multicenter study to implant electrodes in patients with AD– specifically in that fornix region.
According to Dr. Ríos, the majority of these patients actually showed no symptom improvement. However, a handful of patients did see considerable benefits.
This ultimately inspired the current research team to conduct this study in hopes of determining the root cause of these benefit variations.
And to do so, the researchers actually compared the exact position of each patient’s implanted electrodes.
More specifically, Professor Horn’s research team specializes in the analysis of high-resolution magnetic resonance brain images, as well as combining these images with computer models in order to pinpoint optimal DBS implantation locations.
The largest obstacle with this stimulation technique, though, lies in the variation of human brains.
“One of the main challenges is that every brain is different– and that’s really important for accurately planting electrodes. When electrodes are placed even a few millimeters off target, it could lead to a lack of benefit for the patient,” Prof. Horn detailed.
This is essentially what occurred for most of the study’s participants. However, using the brain imaging data, the research team was still able to determine the precise location of electrode implantation among the patients that benefited from the therapy.
It was discovered that the optimal stimulation site lies at the intersection of the fornix and stria terminalis– two brain fiber bundles that connect to deeper regions within the brain. Both of these fibers have also been linked to memory function.
Of course, additional clinical studies are necessary before DBS can be approved and deployed as a mainstream treatment for Alzheimer’s disease.
Nonetheless, the researchers are hopeful that these discoveries will pave the way to that potential reality.
“If our data make it possible to place electrodes more precisely in neurosurgical studies trialing DBS in Alzheimer’s patients, that would be fantastic. We desperately need an effective therapy that alleviates the symptoms of this disease, and DBS is very promising,” Prof. Horn underscored.
To read the study’s complete findings, which have since been published in Nature Communications, visit the link here.
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