, according to an overview of new therapies presented at the XXVI World Congress of Neurology.
One recent study by University of Nottingham researchers showed a wrist-worn stimulating device significantly reduces the frequency and severity of tics – repetitive movements or vocalizations that can occur several times a day.
“Wearable nerve stimulation holds great promise because it will be good across the age spectrum; adults can wear it to work, and children can go to school with it to help them concentrate on their schoolwork, and then they take it off at night,” Eileen Joyce, PhD, MB BChir, professor of neuropsychiatry at the Institute of Neurology, University College London, told this news organization.
Dr. Joyce, who was not part of the study, discussed this and other new advances in tic therapy at the meeting.
About 24% of children will suffer from tics at some point. The prevalence of Tourette syndrome among males is about four times that of females, Dr. Joyce told delegates. She added the typical age of onset is about 7 years with peak severity at about 12 years.
Predictors of tics persisting into adulthood include comorbid attention deficit hyperactivity disorder (ADHD), obsessive–compulsive disorder, and autism spectrum disorder, said Dr. Joyce, who also discussed the “highly heritable” nature of the syndrome and the numerous related genes identified to date.
Current and emerging treatments
Current treatments include psychological therapy, Botox for focal tics, and medications such as antipsychotics. Emerging therapies included deep brain stimulation and the new median nerve stimulation approach.
A study published earlier this year included 135 patients with moderate to severe tic disorder who were randomly assigned to receive the investigational neuromodulation treatment, a sham treatment, or a wait-list treatment group.
The intervention involves rhythmic pulse trains of median nerve stimulation delivered via a device worn at the wrist. The device was programmed to deliver rhythmic (10 Hz) trains of low-intensity (1-19 mA) electrical stimulation to the median nerve at home once daily, 5 days a week for 4 weeks.
At 4 weeks, tic severity, as measured by the Yale Global Tic Severity Scale-Total Tic Severity Score (YGTSS-TTSS), was reduced by 7.1 points (35% reduction) in the active stimulation group compared to 2.13 points in the sham and 2.11 points in wait-list control groups.
The reduction for active stimulation was substantially larger, clinically meaningful (effect size, 0.5), and statistically significant (P = .02) compared to both the sham stimulation and wait-list control groups, which did not differ from one another.
Tic frequency (tics per minute or TPM) was reduced more in the active than sham stimulation groups (−15.6 TPM vs. −7.7 TPM; P < .03) and the reduction in tic frequency was clinically meaningful (>25% reduction; effect-size, 0.3).
When the active stimulator was turned off, the tics worsened, noted Dr. Joyce.
“The study showed that if you stimulate the median nerve at the wrist, you can train brain oscillations that are linked to the suppression of movement,” Dr. Joyce said. “So based on physiological knowledge, they have developed a median nerve stimulator to entrain cortical rhythms.”