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The role of electrode location and stimulation polarity in patient response to cortical stimulation for major depressive disorder. Brain Stimul 2013 May;6(3):254-60



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Pubmed Central ID




Scopus ID

2-s2.0-84877775842   11 Citations


BACKGROUND: Major depressive disorder (MDD) is a neuropsychiatric condition that affects about one-sixth of the US population. Chronic epidural stimulation (EpCS) of the left dorsolateral prefrontal cortex (DLPFC) was recently evaluated as a treatment option for refractory MDD and was found to be effective during the open-label phase. However, two potential sources of variability in the study were differences in electrode position and the range of stimulation modes that were used in each patient. The objective of this study was to examine these factors in an effort to characterize successful EpCS therapy.

METHODS: Data were analyzed from eleven patients who received EpCS via a chronically implanted system. Estimates were generated of response probability as a function of duration of stimulation. The relative effectiveness of different stimulation modes was also evaluated. Lastly, a computational analysis of the pre- and post-operative imaging was performed to assess the effects of electrode location. The primary outcome measure was the change in Hamilton Depression Rating Scale (HDRS-28).

RESULTS: Significant improvement was observed in mixed mode stimulation (alternating cathodic and anodic) and continuous anodic stimulation (full power). The changes observed in HDRS-28 over time suggest that 20 weeks of stimulation are necessary to approach a 50% response probability. Lastly, stimulation in the lateral and anterior regions of DLPFC was correlated with greatest degree of improvement.

CONCLUSIONS: A persistent problem in neuromodulation studies has been the selection of stimulation parameters and electrode location to provide optimal therapeutic response. The approach used in this paper suggests that insights can be gained by performing a detailed analysis of response while controlling for important details such as electrode location and stimulation settings.

Author List

Pathak Y, Kopell BH, Szabo A, Rainey C, Harsch H, Butson CR


Harold H. Harsch MD Professor in the Psychiatry department at Medical College of Wisconsin
Aniko Szabo PhD Professor in the Institute for Health and Equity department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Brain Mapping
Deep Brain Stimulation
Depressive Disorder, Major
Kaplan-Meier Estimate
Linear Models
Prefrontal Cortex
Psychiatric Status Rating Scales
Time Factors