Image of Dr. Lozano​​​
A research team led by KNC neurosurgeon Dr. Andres Lozano has found that DBS could potentially slow the progression of Alzheimer's disease   (Photo: Aaron Szimanski).

Pioneering research in the field of Deep Brain Stimulation (DBS) has shown that the surgically implanted device can help treat neurological and neurodegenerative illnesses such as Parkinson's disease (PD), drug-resistant depression, and movement disorders like dystonia. Early stage research has even shown DBS to have an effect on Alzheimer's disease (AD) and anorexia nervosa.

Thanks to Dr. Andres Lozano and his research team, the Krembil Neuroscience Centre (KNC) of Toronto Western Hospital has put the city on the map as the number one place in the world for DBS research.

And to add to that mantle, a new study recently published by Dr. Lozano's team in the journal Brain Stimulation, shows that DBS may not only alter the symptoms of AD, but also change the structure of the brain and alter certain characteristics of the illness.

"The findings from the research are really novel because they show the effect of DBS goes beyond influencing the function of the brain, it also affects its structure and, in the case of AD, could possibly slow its progression," said Dr. Lozano, a neurosurgeon at KNC and University Professor at the University of Toronto. "It's the first time we've been able to show evidence that DBS changes brain structure in humans."

It is now generally accepted that DBS corrects malfunctioning circuits in the brain by delivering an electrical pulse through a thin electrode that has been implanted in an appropriate area. Doctors use brain mapping to pinpoint the area of the brain where neurons are misfiring and use DBS to adjust their electrical frequency – similar to turning a dial on a standard AM/FM radio to choose a music station and then adjusting the volume. By changing the activity in the circuit with electricity, doctors can alleviate some symptoms associated with neurological illnesses such as the involuntary tremors of (PD).

However, little is known about what – if any – effect DBS has on the overall structure of the brain or the progression of an illness. But according to this research, it may play a role in both.

In 2010, Dr. Lozano's team published a study – the first of its kind in the world – that showed that DBS may help to improve memory in patients with AD​​. The team continued to follow and collect data from the original six patients of that study, upon which their most recent findings are based.

After a year, researchers observed that of the six patients, two showed signs of an increase in the size of their hippocampus, a part of the brain that is damaged in AD and is implicated in memory.  This symptom of brain shrinkage, known as atrophy, is a classic marker of AD and there are no existing drugs or therapies that have been able to stop it.  Interestingly, the growth of the hippocampus with DBS occurred in the two least severely affected patients.

"The findings suggest we can look at DBS as more than a treatment to turn "on/off" misfiring neurons," said Dr. Tejas Sankar the lead author of the study and now a neurosurgeon and researcher at the University of Alberta. "We're still in the early stages, but this opens up a whole new area of research looking at how DBS affects the structure of the brain in relation to neurodegenerative diseases."

The team hopes to further confirm these results by analyzing data from a larger sample size which is currently being studied as part of a second phase clinical trial on DBS for AD patients. They would also like to see whether similar results can be seen in patients with other illnesses such as PD.

At this point, for the expert leading this research field, the findings point to potentially endless possibilities for treating ailments of the brain.

"In our quest to adjust circuits to treat disease, DBS has allowed us to go anywhere in the brain and we're continuously learning new things about this complex organ," remarks Lozano. "Our hope is more research will tell us how to best intervene to modify these neurodegenerative illnesses and improve the lives of our patients."

If you are interested in being considered for future DBS research, please contact: dbs@uhnresearch.ca

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