Contralesional Cathodal versus Dual Transcranial Direct Current Stimulation for Decreasing Upper Limb Spasticity in Chronic Stroke Individuals: A Clinical and Neurophysiological Study.

Different transcranial direct current stimulation (tDCS) paradigms have been implemented to treat poststroke spasticity, but discordant results have been reported. This study aimed to determine the efficacy and persistence of dual tDCS (anode over affected motor cortex [M1] and cathode over contralateral M1) compared with cathodal tDCS (cathode over contralateral M1) on upper limb (UL) functional, behavioral, and neurophysiological measures in chronic poststroke individuals. Ten subjects with UL spasticity (7 men; mean 62 years; 8 ischemic stroke; years from event: 2.3 years) were enrolled in a cross-over, double-blinded study. Cathodal and dual tDCS, both preceded by 1 week of sham stimulation 1 month before real stimulation, were applied with 3 months interval. Stimulating paradigm was 20 minutes for five consecutive days in each block. Evaluations were performed before (T1), after real or sham treatment (T2), and after 1 (T3), 4 (T4), and 8 weeks (T5). Functional, behavioral, and neurophysiological tests were performed at each time. Both tDCS paradigms decreased spasticity, increased strength, and ameliorated behavioral scales. Cathodal tDCS was superior to dual tDCS in reducing UL distal spasticity immediately after treatment (T2: cathodal > dual: P = .023) and provided a higher and longer lasting reduction at proximal districts (T3: cathodal > dual: P = .042; T4: cathodal > dual: P = .028; T5: cathodal > dual: P = .05). These findings are supported by an H-reflex modulation (overall time effect P > .002). Cathodal tDCS is slightly more effective than dual tDCS in reducing distal UL spasticity in chronic poststroke subjects. A modulation of spinal inhibitory mechanisms, demonstrated by H-reflex modifications, supports this finding.

Del Felice A ，Daloli V ，Masiero S ，Manganotti P ... -  《-》

Effects on decreasing upper-limb poststroke muscle tone using transcranial direct current stimulation: a randomized sham-controlled study.

To assess the efficacy of transcranial direct current stimulation (tDCS) on decreasing upper-limb (UL) muscle tone after stroke. A prospective, sham-controlled, randomized controlled trial with 4-weeks follow-up. Randomization into the tDCS group or the control group. Rehabilitation education and research hospital. Inpatients (N=90, 45 per group; age range, 15-70y; 69 men, 21 women; duration of stroke, 2-12mo) with poststroke UL spasticity. No participant withdrew because of adverse effects. The tDCS group received tDCS to the primary sensorimotor cortex of the affected side with cathodal stimulation, 20 minutes per day, 5 days per week, for 4 weeks and conventional physical therapy. The control group received sham stimulation (same area as the tDCS group) and conventional physical therapy. Modified Ashworth scale (MAS), Fugl-Meyer Assessment of motor recovery, and Barthel Index. All outcomes were measured at admission, after treatment, and after follow-up. A clinically important difference (CID) was defined as a reduction of ≥1 in the MAS score. Compared with the sham tDCS group, the active tDCS group had significantly more patients with a clinically important difference after treatment (80% and 78% vs 6% and 9%) and at 4-week follow-up (84% and 82% vs 7% and 4%), and UL motor function and activities of daily living (ADL) assessment improved more significantly in the active tDCS group (Fugl-Meyer Assessment of motor recovery from 12 [range, 4-26] to 22 [range, 7-50] to 32 [range, 28-41], Barthel Index from 55 [range, 0-85] to 85 [range, 5-100] to 90 [range, 10-100 vs Fugl-Meyer Assessment of motor recovery from 8 [range, 3-34] to 10 [range, 8-25] to 15 [range, 6-40], Barthel Index from 55 [range, 25-95] to 65 [range, 30-100] to 75 [range, 40-100], respectively, P<.01). UL muscle tone after stroke can be decreased using cathodal tDCS. Combined with conventional physical therapy, tDCS appears to improve motor function and ADL. Cathodal tDCS over ipsilesional primary sensorimotor cortex may inhibit primary sensorimotor cortex hyperactivation, resulting in significant reductions in muscle tone.

Wu D ，Qian L ，Zorowitz RD ，Zhang L ，Qu Y ，Yuan Y ... -  《-》

Comparison of Neuroplastic Responses to Cathodal Transcranial Direct Current Stimulation and Continuous Theta Burst Stimulation in Subacute Stroke.

To investigate the effects of cathodal transcranial direct current stimulation (tDCS) and continuous theta burst stimulation (cTBS) on neural network connectivity and motor recovery in individuals with subacute stroke. Double-blinded, randomized, placebo-controlled study. University hospital rehabilitation unit. Inpatients with stroke (N=41; mean age, 65y; range, 28-85y; mean weeks poststroke, 5; range, 2-10) with resultant paresis in the upper extremity (mean Fugl-Meyer score, 14; range, 3-48). Subjects with stroke were randomly assigned to neuronavigated cTBS (n=14), cathodal tDCS (n=14), or sham transcranial magnetic stimulation/sham tDCS (n=13) over the contralesional primary motor cortex (M1). Each subject completed 9 stimulation sessions over 3 weeks, combined with physical therapy. Brain function was assessed with directed and nondirected functional connectivity based on high-density electroencephalography before and after stimulation sessions. Primary clinical end point was the change in slope of the multifaceted motor score composed of the upper extremity Fugl-Meyer Assessment score, Box and Block test score, 9-Hole Peg Test score, and Jamar dynamometer results between the baseline period and the treatment time. Neither stimulation treatment enhanced clinical motor gains. Cathodal tDCS and cTBS induced different neural effects. Only cTBS was able to reduce transcallosal influences from the contralesional to the ipsilesional M1 during rest. Conversely, tDCS enhanced perilesional beta-band oscillation coherence compared with cTBS and sham groups. Correlation analyses indicated that the modulation of interhemispheric driving and perilesional beta-band connectivity were not independent mediators for functional recovery across all patients. However, exploratory subgroup analyses suggest that the enhancement of perilesional beta-band connectivity through tDCS might have more robust clinical gains if started within the first 4 weeks after stroke. The inhibition of the contralesional M1 or the reduction of interhemispheric interactions was not clinically useful in the heterogeneous group of subjects with subacute stroke. An early modulation of perilesional oscillation coherence seems to be a more promising strategy for brain stimulation interventions.

Nicolo P ，Magnin C ，Pedrazzini E ，Plomp G ，Mottaz A ，Schnider A ，Guggisberg AG ... -  《-》

Neurophysiological signatures of hand motor response to dual-transcranial direct current stimulation in subacute stroke: a TMS and MEG study.

Kuo IJ ，Tang CW ，Tsai YA ，Tang SC ，Lin CJ ，Hsu SP ，Liang WK ，Juan CH ，Zich C ，Stagg CJ ，Lee IH ... -  《Journal of NeuroEngineering and Rehabilitation》

Personalized upper limb training combined with anodal-tDCS for sensorimotor recovery in spastic hemiparesis: study protocol for a randomized controlled trial.

Levin MF ，Baniña MC ，Frenkel-Toledo S ，Berman S ，Soroker N ，Solomon JM ，Liebermann DG ... -  《Trials》