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Connectivity network predicts effects of deep brain stimulation for OCD

Study findings revealed that specific connectivity profiles — which comprised fronto-thalamic streamlines in the brain — can predict clinical outcome of deep brain stimulation for obsessive-compulsive disorder.

“Although it seems certain that [deep brain stimulation] has effects on distributed brain networks, it remains highly unclear which networks are associated with clinical improvement,” Juan Carlos Baldermann, MD, from the department of psychiatry and psychotherapy, University of Cologne, Germany, and colleagues wrote in Biological Psychiatry.

The researchers examined which brain regions connected to stimulation sites affected clinical improvement effects and whether connectivity could predict outcomes in 22 patients with treatment-refractory OCD undergoing deep brain stimulation (DBS) targeting the anterior limb of the internal capsule/nucleus accumbens.

The investigators calculated stimulation-dependent “optimal” connectivity separately on 10 participants with patient-specific diffusion MRI data and on 12 additional patients using normative connectivity. In addition, they used optimal connectivity models to predict outcome in both an out-of-sample and in a leave-one-out cross-validation across the whole group. They then conducted region of interest analysis to further assess whether connectivity to specific cortical regions would explain clinical improvement.

Analysis revealed that the resulting models yielded correlation coefficients between connectivity and clinical outcome across patients with OCD.

Baldermann and colleagues repeated the same analysis across the full cohort using normative data to define a final model of “optimal connectivity. This also yielded a positive link between connectivity and clinical outcome in areas involving the medial prefrontal cortex and the bilateral lateral prefrontal cortex. Results from a leave-one-out cross-validation further confirmed the model for predicting individual outcomes (r = 0.63; P < .001).

Region of interest analysis of normative connectome data from the whole sample demonstrated a link between clinical improvement and connectivity to the right middle frontal gyrus (r = 0.602; P = .002), according to the results.

“In our sample, increased connectivity of stimulation sites to this fronto-striato-thalamic pathway predicted a large amount of variance in clinical symptom alleviation after one year,” the researchers wrote. “After further validation, these beneficial connectivity patterns may help to guide both stereotactic surgery and DBS programming, in the future. Furthermore, our results may have implications for both cortical and subcortical — and both invasive and noninvasive — neuromodulation protocols.” – by Savannah Demko

Disclosure: Baldermann reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.