A new study may have brought deep brain stimulation one step closer for the treatment of Tourette syndrome.
Researchers reveal that the technique significantly reduced the severity of “tics” in a small group of young adults with the disorder.
Tourette syndrome (TS) is a neurological condition characterized by repetitive, involuntary movements or uncontrollable vocal outbursts, known as tics.
Eye blinking, facial grimacing, jerking of the head or shoulders, and repetitive throat-clearing or grunting are some of the most common tics.
In more severe cases, people with TS may experience “complex” tics.
Complex motor tics are synchronized patterns of movement that involve more than one muscle group. For example, a facial grimace combined with a shoulder jerk and a head twist.
Complex vocal tics may include coprolalia – a term used to describe the vocalization of inappropriate words or phrases.
According to the National Institute of Neurological Disorders and Stroke, it is estimated that around 200,000 people in the United States have severe TS.
Onset of TS is most common in childhood. While symptoms usually improve by late adolescence, around 10 to 15 percent experience debilitating symptoms into adulthood.
How deep brain stimulation works
There are medications available to help reduce the severity of tics, but they do not work for all people with TS.
The new research, however, suggests that deep brain stimulation (DBS) could be an alternative treatment option for people with TS who do not respond to current therapies.
Dr. Alon Mogilner, a study co-author who works in the departments of neurosurgery and anesthesiology at NYU Langone Medical Center in New York – and his colleagues published their results today in the Journal of Neurosurgery.
To reach their findings, the researchers enrolled 13 young adults aged between 16 and 33 years who had severe TS.
All adults underwent DBS, which involved the surgical insertion of two electrodes into the medial thalamus – a brain region that functions abnormally in people with TS.
Over the next few days, participants underwent a second surgery that involved attaching a neurostimulator to the electrodes – a pacemaker-like device that delivers electrical impulses to the medial thalamus.
Tic severity reduced
Before and after DBS, the team assessed the subjects’ tic severity using the Yale Global Tic Severity Scale (YGTSS).
Participants were followed-up for at least six months and they underwent a number of assessments during this time.
At the first assessment after DBS, the researchers found that participants’ tic severity had been reduced by around 37 percent. By the final assessment, the severity of tics had decreased by 50 percent.
Furthermore, in a survey conducted six months after DBS, participants reported that the severity of their TS symptoms had improved “much” or “very much.”
Additionally, all patients – even those who experienced some complications – said that they would undergo the procedure again.
"The survey represents an important aspect of the study because the YGTSS, though a validated scale, may not fully capture the impact of DBS on quality of life for a person with Tourette syndrome,” said Dr. Michael Pourfar, another study co-author who works in the departments of neurosurgery and anesthesiology at NYU Langone.
At present, DBS is considered an “investigational” treatment for TS, as it has yet to receive approval from the Food and Drug Administration (FDA) for this purpose.
However, Mogilner and colleagues believe that their findings could change this.
"Our study shows that deep brain stimulation is a safe, effective treatment for young adults with severe Tourette syndrome that cannot be managed with current therapies," said Mogilner. "This treatment has the potential to improve the quality of life for patients who are debilitated through their teenage years and young adulthood.