Brain stimulation alongside walking and thinking practice

Intervention: This is a two-arm, double-blind, randomized controlled clinical trial. A total of 26 participants diagnosed with Parkinson's disease will be enrolled and randomly allocated into two groups, with 12 participants assigned to the active transcranial direct current stimulation plus dual-task training group and 14 participants assigned to the sham transcranial direct current stimulation plus dual-task training group. Randomization will be performed using a computer-generated block randomization sequence prepared by an independent researcher, with allocation concealment ensured through sequentially numbered, sealed, opaque envelopes. Participants will be assigned according to the order of enrollment. Double blinding will be maintained, with participants and researchers responsible for the assessments and interventions remaining unaware of group allocation. Only one researcher, who will not participate in the assessments or data analysis, will be responsible for programming the stimulation device. Both groups will use the same device and follow identical procedures, differing only in the delivery of electrical stimulation. The active transcranial direct current stimulation group will receive a current intensity of 2 milliamperes for 20 minutes through 5 × 7 centimeter sponge electrodes positioned over the left dorsolateral prefrontal cortex and the supplementary motor area using a Y-shaped montage, with the return electrode placed over the right supraorbital region. The sham transcranial direct current stimulation group will receive the same electrode placement; however, the current will be delivered only during the initial and final seconds of the session to simulate the sensation of stimulation without producing a sustained physiological effect. Simultaneously with the Primary outcome: To evaluate dual-task performance in individuals with Parkinson's disease undergoing transcranial direct current stimulation associated with gait training. Performance will be assessed using the Timed Up and Go test in a numerical and verbal dual-task. Total execution time in seconds, number of responses given, number of correct answers, and cadence during task execution will be analyzed at baseline, after the 9th session, after the 18th session, and 30 days after the end of the intervention.;To evaluate functional balance in individuals with Parkinson's disease undergoing transcranial direct current stimulation associated with gait training. This will be verified using the Mini-Balance Evaluation Systems Test (Mini-BESTest). The total score obtained in points will be analyzed at baseline, after the 9th session, after the 18th session, and 30 days after the end of the intervention.;To evaluate gait performance in individuals with Parkinson's disease undergoing transcranial direct current stimulation associated with gait training. This will be verified using the 10-meter walk test and the simple Timed Up and Go test. The total execution time in seconds, the average gait speed in meters per second, and the cadence in steps per second will be analyzed at baseline, after the 9th session, after the 18th session, and 30 days after the end of the intervention. Secondary outcome: To evaluate the cost of dual-task training in individuals with Parkinson's disease undergoing transcranial direct current stimulation combined with gait training. This will be verified by comparing performance in the single-task Timed Up and Go test with dual-task training. The percentage differences between the single-task and dual-task conditions will be analyzed for execution time, cadence, number of responses, and number of correct answers at baseline, after the 9th session, after the 18th session, and 30 days after the end of the intervention.;To evaluate gait cadence in individuals with Parkinson's disease undergoing transcranial direct current stimulation associated with gait training. This will be assessed using the 10-meter walk test, the simple Timed Up and Go test, and the dual-task Timed Up and Go test. Cadence values ??in steps per second will be analyzed at baseline, after the 9th session, after the 18th session, and 30 days after the end of the intervention.;To evaluate gait cadence in individuals with Parkinson's disease undergoing transcranial direct current stimulation associated with gait training. This will be assessed using the 10-meter walk test, the simple Timed Up and Go test, and the dual-task Timed Up and Go test. Cadence values ??in steps per second will be analyzed at baseline, after the 9th session, after the 18th session, and 30 days after the end of the intervention.;To evaluate freezing of gait in individuals with Parkinson’s disease undergoing transcranial direct current stimulation associated with gait training. Verified using the Freezing of Gait Questionnaire (FOG-Q). The total score in points will be analyzed at baseline, after the 9th session, after the 18th session, and 30 days after the end of the intervention.;To evaluate clinical motor performance in individuals with Parkinson’s disease undergoing transcranial direct current stimulation associated with gait training. Verified using the Movement Disorder Society – Unified Parkinson’s Disease Rating Scale, Part III (MDS-UPDRS III). The total motor score in points will be analyzed at baseline, after the 9th session, after the 18th session, and 30 days after the end of the intervention. ;To evaluate instrumented parameters of postural sway and motor performance in individuals with Parkinson’s disease undergoing transcranial direct current stimulation associated with gait training. Verified using inertial sensors attached to the lumbar region during static balance tests. Mediolateral Root Mean Square, anteroposterior Root Mean Square, total deviation, ellipse area, total mediolateral power, and total anteroposterior power will be analyzed at baseline, after the 9th session, after the 18th session, and 30 days after the end of the intervention.