High-frequency dTMS May Improve OCD Symptoms
SAN ANTONIO—High-frequency deep transcranial magnetic stimulation (dTMS) offers promise as a treatment for patients with obsessive compulsive disorder (OCD), reports a new study presented at Psych Congress.
Increasing evidence suggests a dysfunctional cortico-striato-thalamo-cortical circuit could be involved in the brains of patients with obsessive compulsive disorder, researchers explained. However, conventional TMS has been unable to target cortico-striato-thalamo-cortical circuits directly.
“The use of dTMS coils allows direct stimulation of deeper neuronal pathways relative to those affected by conventional TMS coils,” researchers wrote. “We evaluated whether dTMS targeting the medial prefrontal and the anterior cingulate cortices may influence symptom severity.”
The double-blind controlled study involved 40 patients with OCD. Patients received dTMS with the H7 coil at either a high frequency (20Hz) or low frequency (1Hz) or received sham treatment for 5 weeks. Before treatment, researchers provoked patients’ OCD symptoms to activate OCD circuitry. Electroencephalogram (EEG) measurements were recorded both at baseline and at the end of treatment.
Patients who received high-frequency dTMS had significant improvements in Yale-Brown Obsessive Compulsive Scale scores, compared with patients who received low-frequency dTMS or sham treatment (26% reduction vs 6% reduction), researchers reported. The treatment effects lasted 3 months.
In addition, EEG measurements showed that responses over the anterior cingulated cortex correlated with patient response, researchers noted, “providing an objective measure or biomarker of dTMS efficacy.”
“Two things were exciting to me,” said researcher Aron Tendler, MD. “First is the fact that high-frequency stimulation of the anterior cingulate cortex rather than low-frequency stimulation was effective. High-frequency stimulation is considered facilitatory. Low-frequency stimulation is generally inhibitory. Patients with OCD have increased error-related negativity. We found that patients who got better had even more enhanced EEG activity over the stimulated area, suggesting part of the mechanism of improvement, increasing activity, allows for increased flexibility in this rigid group of patients.”
Zangen A, Carmi L, Alyagon U, Zohar J, Tendler A. Deep transcranial magnetic stimulation of the anterior cingulate cortex for obsessive compulsive disorder patients. Poster presented at 29th Annual U.S. Psychiatric & Mental Health Congress; October 21-24, 2016; San Antonio, TX. Poster 131.