An interventional study of Active Transcranial Direct Current Stimulation (tDCS) and Sham Transcranial Direct Current Stimulation (tDCS) in Parkinson Disease (PD), sponsored by Universidade Metodista de Piracicaba. Completed at 1 site in Brazil. Open to participants aged 45 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-11-09.
Sponsored by Universidade Metodista de Piracicaba · Not applicable, Interventional, and Treatment
Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor and non-motor impairments that negatively affect functional independence and quality of life. Although multimodal rehabilitation approaches have demonstrated therapeutic benefits, underlying pathophysiological mechanisms may limit the magnitude and persistence of treatment effects. In this context, transcranial direct current stimulation (tDCS) has emerged as a potential strategy to enhance neuroplasticity and optimize motor responses to physical rehabilitation.
This randomized, double-blind, sham-controlled clinical trial aimed to investigate the effects of tDCS combined with Nordic walking as part of a multimodal rehabilitation program on upper limb function in individuals with Parkinson's disease. Participants were randomly assigned to receive either active or sham tDCS, both combined with the same multimodal rehabilitation program over four consecutive weeks. Upper limb motor performance, manual dexterity, handgrip strength, and quality of life were assessed before and after the intervention, as well as at a 30-day follow-up. Data were analyzed using linear mixed-effects models, with a significance level of 5%.
Background and Rationale
Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor and non-motor impairments that negatively affect functional independence and quality of life. Upper limb motor dysfunction is particularly relevant in individuals with PD, as bradykinesia, rigidity, tremor, and impaired motor coordination can compromise manual dexterity, movement amplitude, and the performance of activities of daily living.
Nordic walking (NW) is a physical exercise modality that promotes active upper limb involvement during gait through the use of specialized poles, encouraging interlimb coordination, rhythmic movements, and neuromuscular activation. This exercise modality has been investigated as a therapeutic strategy to improve motor performance, functional mobility, and quality of life in individuals with PD.
However, disease-related alterations in cortical excitability and neural plasticity may limit the magnitude and persistence of exercise-induced improvements. Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique capable of modulating cortical excitability and potentially enhancing motor learning and training-induced neuroplasticity. Combining tDCS with Nordic walking may therefore provide additional therapeutic benefits for upper limb motor function in individuals with PD.
Study Objective
The objective of this study was to investigate the effects of active tDCS compared with sham tDCS, both combined with Nordic walking, on upper limb motor performance, manual dexterity, handgrip strength, and quality of life in individuals with Parkinson's disease. The study also investigated whether the effects of the intervention were maintained at a 30-day follow-up.
Study Design
This was a prospective, randomized, double-blind, sham-controlled clinical trial conducted at the State University of Pará (UEPA), Belém, Pará, Brazil, between June 2025 and April 2026.
A total of 34 individuals with Parkinson's disease were randomized into two parallel groups in a 1:1 allocation ratio: an experimental group receiving active tDCS combined with Nordic walking (n = 17) and a control group receiving sham tDCS combined with Nordic walking (n = 17).
The randomization sequence was generated by an independent researcher using Microsoft Excel 2016. Allocation concealment was ensured through sequentially numbered, sealed, opaque envelopes. Following baseline assessment, an independent researcher assigned an individual numerical code to each participant. The code was entered into the stimulation device, which automatically delivered the corresponding active or sham stimulation protocol without revealing the allocation.
Participants and researchers responsible for assessments and intervention delivery remained blinded to group allocation throughout the study.
Intervention Protocol
The intervention program consisted of 12 sessions conducted three times per week over four consecutive weeks. Both groups received the same Nordic walking protocol, differing exclusively in the application of active or sham tDCS.
Before beginning the intervention program, all participants completed two familiarization sessions with Nordic walking, without tDCS.
Transcranial Direct Current Stimulation
Transcranial direct current stimulation was administered using a Microestim-NKL electrical stimulation device with silicone electrodes covered by saline-soaked sponges.
The anodal electrode was positioned over the supplementary motor area (SMA), while the cathodal electrode was placed over the right frontopolar region (Fp2), according to the international 10-20 electroencephalography system.
In the experimental group, active stimulation was delivered at an intensity of 2 mA for 20 minutes per session, with 30-second ramp-up and ramp-down periods.
In the control group, sham stimulation was administered using the same electrode montage and initial stimulation parameters. The device delivered current for approximately 30 seconds before automatically discontinuing stimulation, without visual or auditory signals. This procedure was intended to reproduce the initial scalp sensations associated with active stimulation and preserve participant blinding.
Nordic Walking Training
Nordic walking was performed according to the principles of the International Nordic Walking Federation (INWA). Participants used specialized walking poles and received instructions regarding upright posture, coordinated movements of the upper and contralateral lower limbs, trunk stabilization, shoulder and pelvic girdle dissociation, and active pole propulsion.
Training sessions were conducted along an approximately 1-km outdoor circuit at the State University of Pará. The route included different surfaces, such as paved pathways, grass, ramps, and indoor corridors, to promote neuromuscular adaptation and dynamic postural control.
Walking speed was self-selected, and the total distance covered was individualized according to each participant's functional capacity and exercise tolerance. Five minutes of regular walking were performed before and after the main activity as warm-up and cool-down periods.
Outcome Assessments
Participants underwent clinical and functional assessments at baseline, immediately after the four-week intervention, and at a 30-day follow-up.
Upper limb motor performance was assessed using the upper limb subscore of Part III of the Unified Parkinson's Disease Rating Scale (UL-UPDRS-III), focusing on motor manifestations affecting the upper limb most affected by Parkinson's disease, including tremor, rigidity, finger tapping, hand movements, and pronation-supination movements.
Manual dexterity was evaluated bilaterally using the Box and Block Test (BBT), which measures the number of wooden blocks transferred between compartments within 60 seconds.
Handgrip strength was measured bilaterally using a hand dynamometer, following standardized procedures with three attempts and calculation of the mean value.
Quality of life was assessed using the 39-item Parkinson's Disease Questionnaire (PDQ-39), which evaluates eight dimensions of health-related quality of life.
All assessments and interventions were conducted during the ON medication state to minimize the influence of motor fluctuations. Heart rate, peripheral oxygen saturation, and blood pressure were monitored before and after intervention sessions.
Statistical Analysis
Statistical analyses were performed using Jamovi software, version 2.6. Descriptive statistics were used to characterize the study population, and the Shapiro-Wilk test was applied to assess the normality of continuous variables.
Baseline comparisons between groups were conducted using Student's t-test or the Mann-Whitney U test, as appropriate, while categorical variables were compared using Fisher's exact test.
Outcome analyses followed the intention-to-treat principle and were conducted using linear mixed-effects models to examine group-by-time interactions. The significance of these interactions was assessed using likelihood ratio tests. When significant interactions were identified, post hoc comparisons were performed with Holm-Bonferroni adjustment for multiple comparisons.
Hedges' g was calculated to estimate effect sizes for between-group comparisons. Statistical significance was established at 5% (p \< 0.05).
Ethical Considerations
The study was conducted in accordance with Brazilian National Health Council Resolution No. 466/2012 and was approved by the Research Ethics Committee of the State University of Pará (CEP/UEPA), under ethical approval identification number CAAE 86894625.0.0000.8767. All participants provided written informed consent before participating in the study.
4,573 studies on the registry are indexed under Parkinson Disease; 1,086 are open to participants now.
This study's enrollment of 34 is below the median of 40 across 3,353 interventional studies indexed under Parkinson Disease.
Browse Parkinson Disease studies →Universidade Metodista de Piracicaba is the lead sponsor of 35 studies on the registry; 2 are open to participants now.
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Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
MMSE and MoCA
Short tests of memory and thinking, each scored out of 30. Lower scores suggest more difficulty; criteria give a range, either to include people with memory problems or to leave them out.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants allocated to the experimental group received active transcranial direct current stimulation (tDCS) combined with Nordic walking. Active tDCS was administered at an intensity of 2 mA for 20 minutes, with the anode positioned over the supplementary motor area (SMA) and the cathode over the right frontopolar region (Fp2). The intervention consisted of 12 sessions conducted three times per week over four consecutive weeks. Nordic walking was performed using specialized poles, with walking intensity and distance individualized according to each participant's functional capacity.
Device: Active Transcranial Direct Current Stimulation (tDCS)
Participants allocated to the control group received sham transcranial direct current stimulation (tDCS) combined with Nordic walking. Sham stimulation was administered using the same electrode montage as the experimental group; however, electrical current was automatically discontinued after approximately 30 seconds to reproduce the initial sensations of active stimulation while maintaining participant blinding. The intervention consisted of 12 sessions conducted three times per week over four consecutive weeks. Participants followed the same Nordic walking protocol as the experimental group.
Device: Sham Transcranial Direct Current Stimulation (tDCS)
Active transcranial direct current stimulation (tDCS) was delivered using a Microestim-NKL device with saline-soaked sponge electrodes. The anode was positioned over the supplementary motor area (SMA), and the cathode over the right frontopolar region (Fp2), according to the international 10-20 EEG system. Stimulation was administered at 2 mA for 20 minutes per session, with 30-second ramp-up and ramp-down periods. Participants received 12 sessions, three times per week for four consecutive weeks, combined with Nordic walking.
Sham transcranial direct current stimulation (tDCS) was delivered using the same device and electrode montage as the active stimulation group. Electrical current was applied for approximately 30 seconds and then automatically discontinued to reproduce the initial scalp sensations associated with active stimulation and maintain participant blinding. Participants underwent 12 sham stimulation sessions, three times per week for four consecutive weeks, combined with Nordic walking.
Change in Upper Limb Motor Function Assessed by the MDS-UPDRS Part III
Upper limb motor function was assessed using the upper limb motor items of Part III of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS). The assessment focused on the most affected upper limb and included motor manifestations such as rigidity, finger tapping, hand movements, pronation-supination movements, and tremor. Higher scores indicate greater motor impairment, whereas lower scores indicate better motor function. Changes in scores were evaluated across the three assessment time points.
Time frame: Baseline, immediately after the 4-week intervention, and 30 days after intervention completion (follow-up).
Plan to share: No — Individual participant data (IPD) will not be made publicly available due to ethical considerations regarding participant confidentiality and privacy. The study involves individuals with Parkinson's disease, and the protection of sensitive health information will be maintained in accordance with the informed consent procedures and applicable ethical regulations.
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Universidade Metodista de Piracicaba