Background:
There is growing evidence even amongst those with chronic aphasia that transcranial direct current stimulation (tDCS) combined with behavioral speech therapy could boost language. However, current findings do not allow making strong recommendations for using tDCS in order to improve language in post-stroke aphasia. The efficacy of tDCS therefore still needs to be established using double-blind controlled randomized trials in large samples.
Intervention:
In this ongoing double-blind randomized placebo controlled trial study, participants were randomly assigned either to the tDCS group or to the sham group. Both groups had five consecutive days of 20 minutes session, using a FDA approved tDCS device (soterixmedical.com). Behavioral and neuroimaging data were performed the week before/after tDCS/sham intervention and again 3 months following treatment.
Participants:
42 post-stroke patients with chronic aphasia (32 males; age: 61±11y; 0.9-18years post-injury; 32 ischemic stroke; 19 non-fluent aphasia). Eighteen patients were in the tDCS group.
Main Outcome Measures:
The Western Aphasia Battery-Revised (WAB-R), Communication Outcomes after Stroke, patient and family report (COAST). MRI Diffusion Tensor Imaging data (64 dir) were also collected.
Statistical Analyses:
Anova with repeated measures was used on the behavioral outcome measures with aphasia severity, age and time since injury as covariates in SPSS. The average fractional anisotropy (FA) and mean diffusivity (MD) were extracted per ROI from each participant and timepoint.
Main Results:
a) Behavioral. Groups differed, pre/post intervention, on the WAB-R total score, for the Auditory-Verbal Comprehension and Repetition subscores; b) Neuroimaging. Change in Spontaneous Speech and Auditory Verbal Comprehension negatively correlated with change in mean MD and FA, respectively, in Superior Cerebellar Peduncle for tDCS, but not sham.
Conclusion:
Our preliminary findings show a higher improvement in language functions (for both receptive and expressive language skills) in response to treatment (vs. sham). Neuroplasticity was observed in superior cerebellar peduncle in response to tDCS mediated language improvement.
Acute effects of transcranial Direct Current Stimulation (tDCS) and Transcutaneous Electrical Spinal Stimulation (TESS) neuromodulation on post-stroke walking performance
