P317 Transcranial direct current stimulation combined with visuo-motor training as treatment for chronic stroke patients

Abstract

Recent studies exploring the combined effect of motor learning and transcranial direct current stimulation (tDCS) have shown conflicting results. The optimization of the employed training paradigms can be one way to maximize treatment effects. Methods A newly developed visuo-motor force tracking task is directed to the improvement of fine force control in the hand. During the task, a target force is presented on a computer screen and controlled by patients by pressing a power grip force manipulandum with the affected hand. In the present pilot study we investigated motor effects of four-week training with the visuo-motor force tracking task combined with tDCS in 11 chronic stroke patients with different levels of paresis. Anodal (0.5 mA; 5 patients) or sham (6 patients) tDCS was applied on the primary motor cortex (M1) of the lesioned side for 20 min twice a day simultaneously with training.Upper Extremity Fugl-Meyer assessment (FMA; the primary outcome measure) was done before, after and on two months follow-up. Parameters of performance – ramp error, hold error, release duration and mean hold force – were calculated. Results Total UE FMA score was significantly increased immediately after the treatment, but had declined at two months follow-up. The most prominent improvement occurred in the shoulderelbow sub-score of the FMA; in this segment (but not in the total UE FMA score) a significantly greater improvement in the Active compared to the Sham group was observed (Fig. 1 Figure options Download full-size image Download high-quality image (338 K) Download as PowerPoint slide ). A clinically significant improvement (FMA > 5) was revealed in four patients out of five in the Active group and in two out of six – in the Sham group. Hold error decreased significantly in all patients; ramp error – in the Active group. Mean Hold Force during the first treatment session predicted the change in total UE FMA score after treatment (Fig. 2 Figure options Download full-size image Download high-quality image (213 K) Download as PowerPoint slide ). Conclusions The results show that this treatment protocol can result in clinically significant improvement of motor function in chronic stroke patients, including patients with severe paresis. Individual clinical characteristics of the patients could explain heterogeneity of results and lack of difference in the total UE FMA score. Performance during the initial session might inform about clinical outcomes and guide tDCS protocol optimization in future combined treatments.