New paper updates guidelines for surgical treatment of Tourette syndrome
Deep brain stimulation surgery treats neurologic disorders by implanting fine electrodes within carefully identified malfunctioning regions of the brain. In 2006, the first recommendations for using deep brain stimulation to treat Tourette syndrome were announced. Now, after an extensive review of the global outcomes of deep brain stimulation surgery for patients with Tourette, a new set of recommendations has been published, including guidance from two University of Florida Health neuroscientists.
The new recommendations include removing the age requirement for deep brain stimulation surgery for patients with severe Tourette syndrome, previously suggested to be 25. Initially, researchers did not recommend surgery for people younger than 25 because their brains — particularly men’s brains — are not yet fully mature, according to Jonathan W. Mink, M.D., Ph.D., chief of pediatric neurology at the University of Rochester and co-chair of the Tourette Syndrome Association scientific advisory board.
“Tics may also become better as children become adults,” said Mink, co-author of the current paper and lead author of the 2006 paper. “Now that we have learned that deep brain stimulation is safe, the absolute age requirements have been dropped.”
Despite dropping the age requirements, Mink said researchers still have not found a way to predict which adolescents and young adults are at risk for a longer-term disability based on what the patient’s symptoms are at a specific age. Even in adults over 25, deep brain stimulation is reserved for those with severe cases of the syndrome, said Kelly D. Foote, M.D., a neurosurgeon at UF Health and co-director of the UF Health Center for Movement Disorders and Neurorestoration. Patients with severe tics are particularly vulnerable.
“I have had patients with Tourette who developed spinal cord injuries, with weakness in arms and legs as well as impaired bowel and bladder control because of repetitive violent movement of their necks,” Foote said. “If someone with severely debilitating Tourette symptoms is 18 years old and shows no sign of their tics resolving spontaneously, then it doesn’t make sense to make them wait until they’re 25.”
The new recommendations also note there is still no consensus on the most effective brain target to stimulate for Tourette.
“Deep brain stimulation surgery is a promising approach based on all the data we have gathered,” Foote said. “Which method is going to be most beneficial is not entirely clear, but we’re still very optimistic.”
At the time the recommendations were first published, only six other papers had reviewed case studies of patients who had been treated with deep brain stimulation surgery.
“The initial recommendations paper was published at a time when there were very few patients and no formal studies reported in the medical literature,” Mink said. “The real motivation for that paper was to set some guidelines for how people should obtain data, and to call attention to the need for investigation into this therapy for Tourette syndrome.”
Foote and Mink said each time a patient is recommended for deep brain stimulation, his or her case would have to gain approval from an institutional review board or ethics committee.
“In Tourette syndrome, we think a very small minority of patients will be candidates for deep brain stimulation surgery,” Foote said. “Most patients with Tourette will be relatively effectively managed with a combination of medication, behavioral therapy and time.”
The new recommendations were updated based on a study group made up of the participating medical centers in the Tourette Syndrome Association International Deep Brain Stimulation for Tourette International Registry and Database, which is headed by UF Health neurology professor Michael S. Okun, M.D. Lauren E. Schrock, M.D., a neurologist at University of Utah Health Care, was lead author of the new paper with help from more than 20 neurologists and neurosurgeons. A Tourette Syndrome Association grant coordinated at the UF Health Center for Movement Disorders and Neurorestoration funded the research.
The Food and Drug Administration approved deep brain stimulation surgery for essential tremor in 1997 and for Parkinson’s disease in 2002. Deep brain stimulation is also FDA-approved under a humanitarian device exemption — an exemption given for use of a device that benefits fewer than 4,000 people in the United States per year — for dystonia in 2003 and obsessive-compulsive disorder in 2009. The FDA has not yet approved the surgery for Tourette syndrome.