Transcranial Direct Current Stimulation Enhances Dual-task Performance in Stroke

Not Applicable

Recruiting

• Conditions: Chronic Stroke

• Registration Number: NCT06818240
• Lead Sponsor: The Hong Kong Polytechnic University

Brief Summary

Stroke often impairs lower limb control, resulting in gait abnormalities and difficulties in dual-task performance, such as walking while engaging in cognitive activities. This study examines the effects of a single session of transcranial direct current stimulation (tDCS) targeting the left dorsolateral prefrontal cortex (DLPFC) on dual-task walking performance in individuals with chronic stroke. Using a cross-over design, participants will undergo two sessions (active or sham tDCS, 7 ± 2 days apart) of stimulation at 2 mA for 30 minutes. Walking performance will be measured using single and dual-task conditions combining motor (e.g., 20 m walk) and cognitive tasks (e.g., word association, random number recall). Primary outcomes include walking speed (m/s), stride length (m), and dual-task cost (DTC) for mobility and cognitive speed.

The study aims to evaluate tDCS as a potential tool to reduce DTC, improve dual-task performance, and improve daily function and quality of life in stroke survivors. Results may guide the development of tailored dual-task interventions in stroke rehabilitation.

Detailed Description

Stroke often results in impaired control of lower limb movement, leading to abnormal gait patterns. During daily activities, walking in the community typically involves performing additional cognitive tasks simultaneously, such as remembering directions or engaging in social interactions. Individuals with stroke are particularly susceptible to dual-task interference and demonstrate a slower gait speed, decreased walking adaptability (e.g., obstacle avoidance), and poorer cognitive task performance during dual-task walking, which can increase the dual-task cost (DTC). Transcranial Direct Current Stimulation (tDCS) is a potential tool to reduce DTC, leading to behavioral modifications and improved cognitive functions. This study aims to investigate the effects of a single session of tDCS targeting the left dorsolateral prefrontal cortex (DLPFC) on dual-task walking performance in individuals with chronic stroke.

The study will be a repeated measure designed with two testing sessions (same time in a day, 7 ± 2 days apart between sessions). People with stroke fulfilling the inclusion and exclusion criteria will be recruited from the local community. In each session, active or shame tDCS will be administered first, followed immediately by randomly assigned single and dual tasks. The stimulation will be delivered using a current stimulator (DC-STIMULATOR MOBILE, NeuroConn, Germany). The intensity is set at 2 mA for 30 min. The anode will be placed over the left DLPFC (F3 according to the EEG 10/20 system), while the cathode over the contralateral supraorbital ridge. The gait measurement is recorded by the Opal IMU sensor module and MobilityLab system (APDM Inc., USA).

Measurements of mobility will consist of two walking conditions: single-task and dual-task walking. For the walking test, we perform 'Stand and Walk for a 20-meter Round Trip (10 meters each way)(SWR), which consists of standing for 10 s, walking 10 m, turning, and walking 10 m back. The total time (TT) taken to complete one SWR test will be recorded. For the single cognitive tasks, participants will remain seated and perform the following: Random number, Word association, Counting forward, Serial subtraction. The time taken to complete each task will be equivalent to the TT recorded during the SSWR test. Additionally, the number of correct responses and errors made during the cognitive tasks will be recorded for further analysis. For the dual tasks, we will combine motor and cognitive tasks to assess dual-task performance. The specific dual tasks include SWR + Random Number, SWR + Word Association, SWR + Counting Forward, SWR + Serial Subtraction, SWR + Head Turns, and SWR+ Visual Fixation. The time taken to complete each task and the number of correct responses and errors made will be recorded for further analysis.

The primary outcomes include gait speed (m/s), stride length (m), and dual-task costs (DTC) for mobility and cognition speed. Each session will last approximately 60 min, including both tDCS and MobilityLab setup, and rest.

The findings may provide valuable insights into the use of tDCS as an adjunctive treatment for stroke patients. By enhancing the cortical activity of the left DLPFC through tDCS, it is anticipated that the dual-task cost would be reduced, which results in better dual-task performance and an improvement in daily function and overall quality of life for stroke survivors.

Study Timeline

• Study Start: 2024-11-01
• Study First Submitted: 2025-01-23
• Status Verified: 2025-02
• Study First Submitted QC: 2025-02-04
• Last Update Submitted: 2025-02-04
• Study First Posted: 2025-02-10
• Last Update Posted: 2025-02-10
• Primary Completion: 2025-02-28
• Study Completion: 2025-02-28

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 50

Inclusion Criteria

• age between 50 and 80 years
• at least 6 months post-first-ever stroke with unilateral motor deficits
• ability to walk independently for at least 10 m without the use of walking aids
• a score of 24 or higher on the Mini-Mental State Examination (MMSE)

Exclusion Criteria

• unstable medical conditions, such as heart failure, uncontrolled hypertension, or cancer
• presence of other comorbidities that could interfere with gait
• history of contraindications to tDCS, such as epilepsy or metal implants
• history of head injury, head surgery, or lower limb orthopedic issues

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Primary Outcome Measures

Name	Time	Method
Stride length	Immediately after the active/sham tDCS intervention	Kinematic data will be collected using a motion tracking system, the MobilityLab system (APDM Inc., Portland, OR, USA), and the Opal IMU sensor module (with 128 Hz sampling frequency). A total of eight sensors will be affixed using velcro belts, positioned on the sternum of the upper body, at the lumbar region, and on pairs of upper legs, lower legs, and feet. Stride length (m) will be recorded during each walking task.
Cognitive response rate	Immediately after the active/sham tDCS intervention	Cognitive performance will be evaluated during each task by the number of correct words per second, defined as the response rate (correct responses/second).
DTC- Cognitive speed	Immediately after the active/sham tDCS intervention	The impact of dual-tasking will be quantified by calculating the dual-task cost (DTC) using the following formula: DTC (%) = (dual task outcome measure-single task outcome measure)/single task outcome measure × 100. For example, DTC-time reflects the variation in time taken to complete the SWR test under dual-task versus single-task conditions. DTC- Cognitive speed represents the variation in response rate under both conditions.
Gait speed	Immediately after the active/sham tDCS intervention	Kinematic data will be collected using a motion tracking system, the MobilityLab system (APDM Inc., Portland, OR, USA), and the Opal IMU sensor module (with 128 Hz sampling frequency). A total of eight sensors will be attached with Velcro straps to the sternum of the upper body, the lumbar region, and pairs of thighs, lower legs, and feet. The walking speed (m/s) will be recorded during each walking task.
DTC- Mobility speed	Immediately after the active/sham tDCS intervention	The impact of dual-tasking will be quantified by calculating the dual-task cost (DTC) using the following formula: DTC (%) = (dual task outcome measure-single task outcome measure)/single task outcome measure × 100. DTC-mobility speed indicates the variation in speed used under dual-task versus single-task conditions.

Trial Locations

Locations (1)

The Hong Kong Polytechnic University; 🇭🇰 Hong Kong, China, Hong Kong