Abstract:Background: Parkinson's disease is a common neurodegenerative disorder with motor and non-motor symptoms. Recently, as adjuvant therapy, transcranial direct current stimulation (tDCS) has been shown to improve the motor and non-motor function of patients with Parkinson's disease (PD). This systematic review aimed to evaluate the existing evidence for the efficacy of tDCS for PD. We included English databases (PubMed, the Cochrane Library, Embase, and Web of Science) and Chinese databases [Wanfang database, Chi… Show more
“…Forth, although we focused mainly on rTMS intervention in this study, several types of new TMS protocols, such as theta burst stimulation (TBS); paired associative stimulation (PAS); and other types of NIBS, including transcranial direct current stimulation (tDCS), started developing rapidly and are worth attention; these new protocols introduced innovative approaches to modulate cortical excitability. 75 , 76 , 77 , 78 …”
“…Forth, although we focused mainly on rTMS intervention in this study, several types of new TMS protocols, such as theta burst stimulation (TBS); paired associative stimulation (PAS); and other types of NIBS, including transcranial direct current stimulation (tDCS), started developing rapidly and are worth attention; these new protocols introduced innovative approaches to modulate cortical excitability. 75 , 76 , 77 , 78 …”
“…To date, large variability has been reported in response to tDCS protocols [ 42 ] accredited to the participants’ clinical profiles and the cognitive decline in PD [ 43 – 45 ]. Using a stratified randomization procedure for age and disease stage, clinical assessments and writing performance were comparable between groups in this study.…”
Writing training has shown clinical benefits in Parkinson’s disease (PD), albeit with limited retention and insufficient transfer effects. It is still unknown whether anodal transcranial direct current stimulation (atDCS) can boost consolidation in PD and how this interacts with medication. To investigate the effects of training + atDCS versus training + sham stimulation on consolidation of writing skills when ON and OFF medication. Second, to examine the intervention effects on cortical excitability. In this randomized sham-controlled double-blind study, patients underwent writing training (one session) with atDCS (
N
= 20) or sham (
N
= 19) over the primary motor cortex. Training was aimed at optimizing amplitude and assessed during online practice, pre- and post-training, after 24-h retention and after continued learning (second session) when ON and OFF medication (interspersed by 2 months). The primary outcome was writing amplitude at retention. Cortical excitability and inhibition were assessed pre- and post-training. Training + atDCS but not training + sham improved writing amplitudes at retention in the ON state (
p
= 0.017,
g
= 0.75). Transfer to other writing tasks was enhanced by atDCS in both medication states (
g
between 0.72 and 0.87). Also, training + atDCS improved continued learning. However, no online effects were found during practice and when writing with a dual task. A post-training increase in cortical inhibition was found in the training + atDCS group (
p
= 0.039) but not in the sham group, irrespective of medication. We showed that applying atDCS during writing training boosted most but not all consolidation outcomes in PD. We speculate that atDCS together with medication modulates motor learning consolidation via inhibitory processes (
https://osf.io/gk5q8/
, 2018-07-17).
Supplementary Information
The online version contains supplementary material available at 10.1007/s00415-023-11669-3.
“…Third, we only investigated the post-intervention effects of singlesession tDCS, but the maintenance effects or accumulative effects of tDCS are not known. Fourth, we applied 2 mA for all targets because the current with 2 mA was most commonly used in the previous studies, especially in the studies focusing on walking ability (Ferrucci et al, 2015;Liu et al, 2021). However, the best parameter for tDCS in different targets may be different.…”
BackgroundTranscranial direct current stimulation (tDCS) is a non-invasive brain stimulation to modulate cortical activity for improving motor function. However, the information of tDCS stimulation on different brain regions for dual-task walking and cortical modulation in Parkinson’s disease (PD) has not yet been compared.ObjectiveThe objective of this study was to investigate the effects of different tDCS targets on dual-task gait performance and cortical activity in patients with PD.MethodsA total of 36 participants were randomly assigned to primary motor cortex (M1) tDCS, dorsal lateral prefrontal cortex (DLPFC) tDCS, cerebellum tDCS, or Sham tDCS group. Each group received 20 min of tDCS stimulation, except for the Sham group. Gait performance was measured by the GAITRite system during dual-task walking and single walking. Corticomotor activity of the tibialis anterior (TA) was measured using transcranial magnetic stimulation (TMS). The functional mobility was assessed using the timed up and go (TUG) test.ResultsAll participants showed no significant differences in baseline data. Following the one session of tDCS intervention, M1 (p = 0.048), DLPFC (p < 0.001), and cerebellum (p = 0.001) tDCS groups demonstrated significant improvements in dual-task gait speed compared with a pretest. The time × group interaction [F(3, 32) = 5.125, p = 0.005] was detected in dual-task walking speed. The post hoc Tukey’s test showed that the differences in gait speed were between the Sham tDCS group and the DLPFC tDCS group (p = 0.03). Moreover, DLPFC tDCS also increased the silent period (SP) more than M1 tDCS (p = 0.006) and Sham tDCS (p = 0.002).ConclusionThe results indicate that DLPFC tDCS exerted the most beneficial effects on dual-task walking and cortical modulation in participants with PD.Clinical trial registration[http://www.thaiclinicaltrials.org/show/TCTR20200909005], Thai Clinical Trials Registry [TCTR20200909005].
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