tDCS and Robotics on Upper Limb Stroke Rehabilitation: Effect Modification by Stroke Duration and Type of Stroke

Abstract

Objective. The aim of this exploratory pilot study is to test the effects of bilateral tDCS combined with upper extremity robot-assisted therapy (RAT) on stroke survivors. Methods. We enrolled 23 subjects who were allocated to 2 groups: RAT + real tDCS and RAT + sham-tDCS. Each patient underwent 10 sessions (5 sessions/week) over two weeks. Outcome measures were collected before and after treatment: (i) Fugl-Meyer Assessment-Upper Extremity (FMA-UE), (ii) Box and Block Test (BBT), and (iii) Motor Activity Log (MAL). Results. Both groups reported a significant improvement in FMA-UE score after treatment (p < 0.01). No significant between-groups differences were found in motor function. However, when the analysis was adjusted for stroke type and duration, a significant interaction effect (p < 0.05) was detected, showing that stroke duration (acute versus chronic) and type (cortical versus subcortical) modify the effect of tDCS and robotics on motor function. Patients with chronic and subcortical stroke benefited more from the treatments than patients with acute and cortical stroke, who presented very small changes. Conclusion. The additional use of bilateral tDCS to RAT seems to have a significant beneficial effect depending on the duration and type of stroke. These results should be verified by additional confirmatory studies.

Neural signature of tDCS, tPCS and their combination: Comparing the effects on neural plasticity

“…Therefore, a single stimulation session might not be enough to generate important clinical changes. Finally, it is more and more evident that the effects of tDCS seem to be greater when coupled with a specific task [38–40]. …”

Efficacy of Transcranial Direct Current Stimulation as Support for Neurorehabilitation Therapy: A Meta-analysis of Available Studies

“…The age range ranged from 34 to 84. Most subjects have chronic stroke, only one study includes only subacute subjects (7-30 days from the event) [16], and another study included both [15]. Bilateral stimulation was administered in majority of trails, while in 2 studies anodal stimulation was investigated [16] and cathodal stimulation in one study [18]; The current intensity varies from 1 mA to 2 mA.…”

“…Six studies involving eight used a bilateral montage, including the anodal stimulation of M1 of the ipsilesional hemisphere (C3 and C4 EEG 10/20 system), cathodal stimulation of M1 of the controlesional hemisphere or cathodal stimulation of the contralateral supraorbital area to the lesion [12][13][14][15][16][17][18][19]. Bilateral montage is often used based on the assumption that the movements of the impaired limbs are often associated with a high level of transcallosal inhibition by the hemisphere not affected by the hemisphere being injured [10,20]; some studies conducted with multimodal imaging techniques and mapping, such as fMRIs and TMSs, confirmed the existence of this imbalance of the hemisphere not affected, also called a hemispheric competition model, particularly during the preparation and execution of upperlimb motor acts [21,22], some authors hypothesize that the amount of this imbalance in inter-hemispheric excitability may be positively correlated with the degree of severity of motor disability [10,6].…”

“…In this meta-analysis studies including subjects with chronic stroke are 6, 1 with subacute stroke and 1 with both. Some evidence [15,[35][36][37] points out, an improvement in the results of subjects with chronic stroke, associated with rehabilitative treatment; Straudi hypothesizes that, according to the model of inter-hemispheric competition, in the subacute phase the increase of the cortical excitability of the contralateral hemisphere to the lesion can be compensatory rather than maladaptive; in this stage, the effects of neuromodulation may be masked by spontaneous recovery, with little further clarity; motor training, in addition, induces a cortical reorganization after a few weeks from the end of treatment suggesting that early rehabilitation therapy could involve the evolution of neural post-stroke networks [12,38].…”

“…Eight studies were considered for a total of 178 subjects included [6,[12][13][14][15][16][17][18]. Computer literacy research has been focused on post-stroke motor recovery studies by administering non-invasive brain stimulation (NIBS) including transcranial direct current stimulation (tDCS); the research period of the literature is between January 2005 and May 2016.…”