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Deep Brain Stimulation, Part 1: How Does It Work?

The use of brain surgery to treat Tourette Syndrome receives a lot of media attention. This three-part blog series from the Tourette Syndrome Foundation of Canada (TSFC) will give you up-to-date information about this treatment approach. Part 1 explains how the surgery works and how it might negatively affect someone with TS.

DBS modelA common question about Tourette Syndrome is about how it’s treated medically. At present, there is no one-size-fits-all answer. How much medical attention or treatment a person receives for tics depends on how the tics impact them—whether they are physically painful and/or make it difficult to function. For fairly minor tics, education and support are often enough. More severe tics can be treated with one or more prescription medications and/or behavior therapy.

For a small number of people with TS, prescription medications have little effect. Their tics are extremely severe and both significantly and negatively impact their quality of life. On top of that, their tics are resistant to medications.

For these individuals, a relatively new surgical approach, called Deep Brain Stimulation or DBS, could be a potential treatment. DBS refers to the direct delivery of an electric pulse to the brain to help moderate abnormal signals associated with TS. The electric pulse comes from an electrode that is implanted directly into the brain and connected to a pulse generator via a cable or lead (pictured above).

The lead and generator are also surgically implanted within the body, with the lead running down the neck and skull, and over the collarbone and pulse generator sitting in the upper chest. Similar to a pacemaker, the generator has a battery and computer that send electric pluses directly to brain via the lead. The device settings—the size, voltage and frequency of the electric pulse—are all adjustable.

The key question is, does DBS have the desired effect of decreasing or eliminating tics?

Again, the answer is complicated. DBS received a lot of positive media hype with some headlines hailing it as a life-changing treatment or even a cure for TS. There have been some positive outcomes in some cases. Within the medical community however, the reaction is mixed.

DBS is controversial partly because it’s so new (not a lot of studies or cases exist) and partly due to questions about side effects and effectiveness. The Canadian Guidelines for the Evidence-Based Treatment of Tourette Syndrome rates DBS as “Insufficient evidence to make a formal recommendation” for adults and “Not recommended” for children (see page 76 of the Guidelines for more information).

These ratings reflect the lack of documented cases and studies on DBS as well as concerns that DBS benefits might actually come from natural waning of tics or the placebo effect rather than the device. Adverse effects like restricted daily activity due to energy loss, skin infection, nausea, vertigo and anxiety are also concerns.

As well, the surgery comes with risks. Current research estimates that infection due to DSB occurs in more than 5 percent of cases. The device has no blood supply. It or the electrodes can potentially damage a blood vessel, which can lead to bleeding or a stroke. DSB often affects one’s ability to get words out and it can worsen mood or cognition. In rare cases, suicidal thoughts result. Finally, depending on the way the procedure is performed, there may be an increased risk of problems with walking, talking and thinking.

For more information on DBS, stay tuned for parts two and three of this blog series.

Sources:

The Canadian Guidelines for the Evidence-based Treatment of Tourette Syndrome (2012)

A Family Guide to Tourette Syndrome (2012)

Parkinson’s Disease: Guide to Deep Brain Stimulation Therapy (2014)

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