Multitarget transcranial direct current stimulation for freezing of gait in Parkinson's disease

Abstract

Background: Recent findings suggest that transcranial direct current stimulation of the primary motor cortex may ameliorate freezing of gait. However, the effects of multitarget simultaneous stimulation of motor and cognitive networks are mostly unknown. The objective of this study was to evaluate the effects of multitarget transcranial direct current stimulation of the primary motor cortex and left dorsolateral prefrontal cortex on freezing of gait and related outcomes.

Methods: Twenty patients with Parkinson's disease and freezing of gait received 20 minutes of transcranial direct current stimulation on 3 separate visits. Transcranial direct current stimulation targeted the primary motor cortex and left dorsolateral prefrontal cortex simultaneously, primary motor cortex only, or sham stimulation (order randomized and double-blinded assessments). Participants completed a freezing of gait-provoking test, the Timed Up and Go, and the Stroop test before and after each transcranial direct current stimulation session.

Results: Performance on the freezing of gait-provoking test (P = 0.010), Timed Up and Go (P = 0.006), and the Stroop test (P = 0.016) improved after simultaneous stimulation of the primary motor cortex and left dorsolateral prefrontal cortex, but not after primary motor cortex only or sham stimulation.

Conclusions: Transcranial direct current stimulation designed to simultaneously target motor and cognitive regions apparently induces immediate aftereffects in the brain that translate into reduced freezing of gait and improvements in executive function and mobility. © 2018 International Parkinson and Movement Disorder Society.

Keywords: Parkinson's disease; brain stimulation; freezing of gait; transcranial direct current stimulation.

© 2018 International Parkinson and Movement Disorder Society.

Figures

FIG. 1

Individual changes in FOG-provoking test scores after multitarget stimulation (A), M1 stimulation (B) or sham stimulation (C). Each line represents outcome for the same subject in the three simulation conditions. Negative values indicate improvement because lower scores on this test reflect less FOG. For example, the square-green line represents an individual that after the multitarget stimulation had a reduction of 8 points, while after stimulating the motor cortex alone had a reduction of 2 points, compared with an increase of 2 points after sham stimulation. Note that even after removing the 3 subjects with the largest reductions, on a group level, the significant improvement after the multitarget stimulation still persisted (p = 0.003). [Color figure can be viewed at wileyonlinelibrary.com]

FIG. 2

The immediate effects of tDCS on FOG, mobility, and executive function. (A) FOG-provoking test scores. (B) Time Up and Go (TUG) test. (C) Stroop interference trial. Bar graphs indicate the change (D) in performance from pre- to post-tDCS, along with standard error. For both the FOG-provoking and the TUG, lower scores indicate better performance. For Stroop interference scores, a larger number of correct words indicates better executive function (ie, response inhibition). [Color figure can be viewed at wileyonlinelibrary.com]