Table 3 Main results of the reviewed studies
First Author (Year) | * Main Results |
|---|---|
• Adverse effects (occurrence) | |
Biundo (2015) [33] | * Active tDCS reduced performance in the attention/executive skills and delayed memory index when compared to sham tDCS at the post-test. |
* Active tDCS tends to improve performance in the immediate memory index compared to the sham group at the follow-up test. | |
* No significant UPDRS-III motor changes were observed between groups at 4 and 16-week follow-up tests. | |
• NR. | |
Broeder (2019) [28] | * Active tDCS decreased the episodes of freezing compared to sham tDCS. |
* No effects of tDCS were found for the amplitude, variability, and speed of the strokes outside the freezing episodes. | |
* Patients who reported freezing episodes in daily life (n = 6) showed a beneficial effect of tDCS on stroke characteristics. | |
• No adverse events of tDCS were reported. | |
Broeder (2019) [34] | * Active tDCS improved writing during the tDCS protocol, at the post-test and at follow-up compared to sham. * Active tDCS increased writing amplitude at follow-up period compared to post period. * Active tDCS enhanced cortical excitability compared to sham at the post-test. |
* Active tDCS enhanced cortical excitability compared to sham at the post-test. | |
• No adverse events of tDCS were reported. | |
Costa-Ribeiro (2016) [31] | * Both groups improved functional mobility either in on or off medication condition compared with baseline. |
* However, for both medication conditions, these gains were maintained only in the tDCS+ gait training at follow-up test. | |
* In the tDCS + gait training, enhancement of cortical excitability was observed at post-intervention and 1-month follow-up (both only for the “on” phase). | |
• NR. | |
Costa-Ribeiro (2017) [35] | * Both groups improved functional mobility (velocity, cadence, and TUG), motor impairment, bradykinesia, balance, and quality of life at post-test. |
*For all outcome measures, no significant differences were found between groups. | |
* The improvement in velocity and TUG were maintained at the follow-up test only for patients in the Cueing gait training + tDCS group. | |
• No adverse events were reported by any of the participants. | |
Criminger (2018) [36] | *No differences were observed for TUG between conditions. |
*Increased DTC in the TUG motor (gait) after a tDCSbike session when compared to tDCSwii. | |
*Increased DTC in the TUG cognitive (cognitive) after a tDCSbike session when compared to tDCSwii. | |
*Increased DTC in the TUG cognitive (gait) after a tDCSwii session when compared to tDCSbike. | |
• 1 participant was excluded from the initial sample (n = 18) after presenting headache in the first session. | |
Fernández-Lago (2017) [37] | * All groups increased velocity, stride length, and short intracortical facilitation at post-test. |
* All groups decreased Hmax/Mmax ratio and intracortical facilitation at post-test. | |
* Sham tDCS + treadmill and treadmill groups decreased reciprocal Ia inhibition at post-test when compared to pre-test. | |
• NR. | |
Forogh (2017) [38] | * Active tDCS + occupational therapy improved fatigue at post-test when compared to baseline. • NR. |
Horiba (2019) [39] | * tDCS + mirror visual feedback increased the number of ball rotations at post-test. * No significant changes on UPDRS-III motor section were observed. • NR. |
Ishikuro (2018) [40] | * Anodal tDCS decreased normalized scores of disease severity (UPDRS III) compared with Sham and Cathodal stimulation. * Anodal stimulation improved executive function and increased normalized scores of sensory-motor functions compared with Sham stimulation. * Anodal stimulation increased normalized scores of STEF compared with Cathodal stimulation. • 55.6% felt mild tingling. No adverse events were reported by any of the participants. |
Kaski (2014) [25] | * tDCS + physical training increased gait velocity and stride length when compared with tDCS. |
* tDCS + physical training decreased the walking time and the time taken to regain stability following the retropulsion stimulus when compared with tDCS. | |
* tDCS + physical training improved the turn phase of TUG. | |
* Sham + physical training decreased walking time and increased stride length but these were comparatively less than with tDCS + physical training. | |
• NR. | |
Kaski (2014) [41] | * Dance + tDCS increased peak trunk velocity in both pitch and roll directions. |
* Dance + tDCS increased for the 90% velocity range and total trunk velocity area. | |
* Dance + tDCS increased gait function. | |
• NR. | |
Lawrence (2018) [42] | * Standard CT improved memory at follow-up test, quality of life, and activities of daily life at post-test. However, decreased visuospatial ability at follow-up test. |
* Tailored CT improved attention/working memory at follow-up and quality of life at post- and follow-up tests. | |
* tDCS improved attention/working memory at post- and follow-up tests, and memory at post-test. | |
* Standard CT + tDCS improved executive function and attention/working memory at post and follow-up tests, and language and quality of life at post-test. | |
* Tailored CT + tDCS improved executive function, memory, and language at post- and follow-up tests, and attention/working memory at the follow-up test. | |
* CG had no improvements. | |
• NR. | |
Manenti (2016) [29] | * Both groups showed improvement in depression at post- and follow-up tests. |
* Physical therapy + tDCS increased PD-CRS total, frontal-subcortical scores and verbal fluency at post, and stabilized the effect at follow-up test. | |
* Physical therapy + tDCS group decreased the time necessary for completing TMT-B at post-test. | |
* Both groups improved the Standing Stork, Four Square Step, and Sit, and Reach Tests at post-test, with improvements maintained at follow-up test for the Standing Stork, Four Square Step tests. | |
* Both groups improved TUG performance at follow-up test. | |
• NR. | |
Manenti (2018) [43] | * Both groups improved language, attentional and executive functions at post and follow-up periods. * Both groups increased phonemic fluency at post-test and semantic fluency at follow-up. * tDCS + computerized cognitive training showed lower depressive symptoms and greater phonemic fluency when compared to Sham + computerized cognitive training at post-test and follow-up. • No adverse events were reported by any of the participants. |
Schabrun (2016) [44] | * Both groups improved gait velocity, cadence, step length and double support time in gait dual-tasks and bradykinesia at post- and follow-up tests. |
* Both groups improved functional mobility during TUG with words at post and follow-up tests. | |
* Active tDCS + dual-task gait training improved the number of correct responses during TUG with counting and TUG with words at post-test, with a trend to maintain this performance in TUG with words at follow-up test. | |
* There were no differences between groups for reaction time and attention. | |
• One participant experienced strong tingling over the site of one electrode and a momentary flash of light in his eyes. The sensations lasted approximately 5 s. The participant ceased training that day but continued on subsequent days with no other events, and no other symptoms. | |
Yotnuengnit (2018) [45] | * All groups improved gait velocity and step time at post-test and at 2nd and 6th week follow-up. |
* Physical therapy group increased cadence at 2nd and 6th week follow-up tests. | |
* tDCS and sham + physical therapy improved UPDRS II in all tests and the tDCS + physical therapy improved at the post and 2 weeks follow tests. | |
* All groups improved UPDRS III at post and 2nd week follow-up tests. | |
• Burning sensation (tDCS group). |