Publication Summary
Transcranial direct current stimulation (tDCS) of the primary motor cortex is a possible therapy to enhance motor rehabilitation after stroke. The aim of this study is to determine any potential autonomic effects of the tDCS electrode montage conventionally used in stroke therapy. The study was approved by the University of Leeds Ethics Committee and conducted in accordance with the Declaration of Helsinki. tDCS was applied over the primary motor cortex at 1mA with a reference electrode placed on the contralateral supraorbital region in 16 healthy subjects (20–48 years; 7 female, 9 male). Subjects visited the department twice and received active or sham tDCS for 10 minutes. Active tDCS was anodal (n=8) or cathodal (n=8). Heart rate (HR), blood pressure (BP) and respiration were recorded at baseline, during tDCS and recovery. ECG data underwent power spectral analysis to calculate heart rate variability (HRV). HRV did not change significantly (p>0.05) however there was a 32% increase in LF/HF ratio (a measure of sympathovagal balance) during anodal tDCS that continued into recovery reaching 42% above baseline. This indicates a trend towards increased sympathetic activity that was supported by a significant increase in LF power (p=0.048) in the anodal tDCS group. These results suggest further investigation is required before tDCS should be used for stroke therapy. This research is supported by the University of Leeds.
CAER Authors
Prof. Mark Mon-Williams
University of Leeds - Chair in Cognitive Psychology