Acute and chronic changes in brain activity with deep brain stimulation for refractory depression

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Deep brain stimulation (DBS) is a therapeutic option for treatment-refractory depression.
• Previous studies suggest targeting the subgenual cingulate or ventral anterior capsule/nucleus accumbens for DBS benefits.
• Optimal stimulation sites and patient response variability remain areas of uncertainty.

Purpose of the Study:

• To compare the efficacy of DBS targeting the subgenual cingulate versus the ventral anterior capsule/nucleus accumbens, both separately and combined, in patients with treatment-refractory depression.
• To investigate regional cerebral blood flow (rCBF) changes associated with acute and chronic DBS.
• To explore potential biomarkers for DBS treatment response and remission.

Main Methods:

• A within-subject design comparing DBS of subgenual cingulate and ventral anterior capsule/nucleus accumbens in seven patients with treatment-refractory depression.
• Assessment of deep brain stimulation response (≥50% Montgomery-Asberg Depression Rating Scale score reduction) and remission (Montgomery-Asberg Depression Rating Scale score ≤8).
• Regional cerebral blood flow (rCBF) measurement using [15O]water positron emission tomography (PET) during acute and chronic DBS, and after DBS interruption.

Main Results:

• Patients achieving remission had significantly higher baseline prefrontal cortex rCBF compared to non-remitters and non-responders.
• Prefrontal cortex rCBF generally increased with chronic DBS, irrespective of the stimulation target.
• No significant rCBF changes were observed upon acute interruption of DBS.

Conclusions:

• Deep brain stimulation improved depression severity in most patients, with consistent brain-wide rCBF changes regardless of stimulation site.
• Higher baseline prefrontal cortex rCBF may predict remission in patients undergoing DBS for treatment-refractory depression.
• Further research is needed to validate prefrontal cortex rCBF as a predictive biomarker for DBS treatment response due to the small sample size.