Double-blind optimization of subcallosal cingulate deep brain stimulation for treatment-resistant depression: a pilot study.

TLDR: Longer pulse width stimulation may have a role in stimulus optimization for SCC-DBS in TRD, suggesting that the authors do not yet know the optimal target or stimulus parameters for this therapy.

Abstract: Background: Deep brain stimulation (DBS) of the subcallosal cingulate (SCC) is reported to be a safe and effective new treatment for treatment-resistant depression (TRD). However, the optimal electrical stimulation parameters are unknown and generally selected by trial and error. This pilot study investigated the relationship between stimulus parameters and clinical effects in SCC-DBS treatment for TRD. Methods: Four patients with TRD underwent SCC-DBS surgery. In a double-blind stimulus optimization phase, frequency and pulse widths were randomly altered weekly, and corresponding changes in mood and depression were evaluated using a visual ana logue scale (VAS) and the 17-item Hamilton Rating Scale for Depression (HAM-D-17). In the open-label postoptimization phase, depres sive symptoms were evaluated biweekly for 6 months to determine long-term clinical outcomes. Results: Longer pulse widths (270‐450 s) were associated with reductions in HAM-D-17 scores in 3 patients and maximal happy mood VAS responses in all 4 pa tients. Only 1 patient showed acute clinical or mood effects from changing the stimulation frequency. After 6 months of open-label ther apy, 2 patients responded and 1 patient partially responded. Limitations: Limitations include small sample size, weekly changes in stimu lus parameters, and fixed-order and carry-forward effects. Conclusion: Longer pulse width stimulation may have a role in stimulus optimization for SCC-DBS in TRD. Longer pulse durations produce larger apparent current spread, suggesting that we do not yet know the optimal target or stimulus parameters for this therapy. Investigations using different stimulus parameters are required before embark ing on large-scale randomized sham-controlled trials.