Deep Brain Stimulation (DBS)

Deep Brain Stimulation (DBS) is a form of brain stimulation that involves invasive neurosurgical intervention and implantation of electrodes under MRI guidance into specific brain regions.[1] It remains an investigational and experimental treatment.

  • DBS acts via different mechanisms including causing local neuronal and whole-brain electrophysiological changes secondary to stimulation, changes in synaptic plasticity, modulation of oscillatory waves in the brain, and possibly a role in causing neurogenesis via release of growth factors.[2]
  • The implanted electrodes are peripherally connected to an implantable pulse generator (IPG) that is usually implanted in chest below the right clavicle.
    • Settings can be adjusted on this IPG.
  • In treatment-resistant depression, the neuroanatomical targets are the subcallosal cingulate (SCC) white matter, ventral capsule/ventral striatum (VC/VS), nucleus accumbens, and medial forebrain bundle (MFB).
    • The majority of DBS research studies have focused on the subcallosal cingulate.[3]
  • Similar to cardiac pacemakers and VNS, the IPG in DBS can be accessed using a handheld device, allowing the stimulation parameters to be monitored and/or programmed remotely. Modifiable DBS parameters include pulse width, frequency, and amplitude (voltage or current), which can be programmed by the treating physician and titrated to clinical effect.
  • The optimal stimulation parameters for different brain regions remains unknown.
  • For treatment-resistant depression, response rates of 30% to 60%, and remission rates of 20% to 40% at 3 to 6 months have been reported.[4]
  • Adverse events related to the neurosurgical procedure involve intracranial haemorrhage, and perioperative risks such as from general anesthesia and wound infections.
  • Non-surgical adverse events include psychosis and hypomania caused by a change in the stimulation parameters in patients receiving DBS in the nucleus accumbens.
  • Oculomotor adverse events such as blurred vision and strabismus, have been reported with medial forebrain bundle DBS.
  • Cases of suicidality and completed suicide have been reported in DBS studies, but there has been no evidence to show that these were DBS or device related events.

Neurostimulation in the Treatment of Major Depressive Disorder

Milev, R. V. et al. (2016). Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 clinical guidelines for the management of adults with major depressive disorder: section 4. Neurostimulation treatments. The Canadian Journal of Psychiatry, 61(9), 561-575.
Neurostimulation Overall Recommendation Acute Efficacy Maintenance Efficacy Safety and Tolerability
rTMS • First line (for patients who have failed at least 1 antidepressant) Level 1 Level 3 Level 1
ECT • Second line
• First line in some acute clinical situations
Level 1 Level 1 Level 1
tDCS • Third line Level 2 Level 3 Level 2
Vagal Nerve Stimulation (VNS) • Third line Level 3 Level 2 Level 2
DBS • Investigational Level 3 Level 3 Level 3
MST • Investigational Level 3 Not known Level 3