Randomized, Triple-Blind, and Parallel-Controlled Trial of Transcranial Direct Current Stimulation for Cognitive Rehabilitation after Stroke

We studied the efficacy of combining tDCS with computerized cognitive stimulation in the treatment of hemispatial neglect in comparison to cognitive stimulation alone, aiming to enhance stroke cognitive rehabilitation outcomes.

Scientific evidence show that conventional tDCS improve hemispatial neglect after a stroke, but there is no evidence about the efficacy of high-definition tDCS combined with cognitive stimulation.

While the use of technology is quite common in other rehabilitation areas, cognitive intervention has not yet fully adapted. It seems that recent advances in artificial intelligence and neuropsychological digitalization is going to improve this situation.

This study addresses the lack of evidence on efficacy and focal benefits of high-definition transcranial direct current stimulation and cognitive rehabilitation in post-stroke hemispatial neglect.

Future research will explore tDCS-based neuromodulation for pain and fatigue in brain damage, multiple sclerosis, and post-COVID syndrome, integrating results from neurodegenerative diseases and using clinical and neurophysiological biomarkers as well as remote neuromodulation protocols.

[Narrator] To begin, explain the test to the participant and ask them to follow the test instructions. Confirm that the total score is greater than or equal to 24 points to proceed. For the line bisection and bells test, place the task centered in front of the participant and indicate on the sheet the right and left sides from the participant's perspective. Explain the test and ask the participant to follow the instructions. To administer the picture drawing subtests of the Barcelona test, place the task in front of the participant. Point to the pictures that appear. After explaining the test, have the participant follow the instructions. To administer the cancellations subtests of the Barcelona test, place the task in front of the participant and indicate the right and left sides of the participant on the sheet. Have the participant follow the test instructions. For the digit span forward and backward tests, verbally administer the direct digit task. Then administer the inverse digits task. To administer the brief test of attention, first administer the verbal part of the first task by asking the participant to count the numbers that appear in sequence. Then ask the participant to immediately apply the second part, which is to count the number of letters that appear in the sequence. For the face test, present the face test sheet to the participant. Explain the test and ask them to follow the instructions. For the motor free visual perception test, place the homework notebook in front of the participant. Explain the test and ask them to follow the instructions. To know the patient's functional status, administer the Barthel Index Scale to the family member or primary caregiver. Record their responses on the answer sheet. Then administer the Catherine Bergego Scale to the family member or primary caregiver, and record responses on the answer sheet. To configure the intervention device, first launch the software, select protocol editor, add a new protocol, and enter the name of the protocol. Confirm the ramp and total stimulation time by indicating ramp-up 30 and ramp-down 30. In the total stimulation duration section, indicate 20 minutes and press the sham button if it corresponds to the condition, then select the stimulation program to begin configuring the tDCS and basic electrodes that will be part of the setup configuration. Then select electrode P3 and drag it to the box on the right. Choose stimulation and cathodal and enter 2,000 microamperes. Then select and drag to the left and space the return electrodes one by one, indicating the return percentage for each. Click the Finish button once complete. Assess the level of mental fatigue and mood using two self-administered VAS scales. Ask the participant to provide a score from one to 10 for each question where one is the lowest mental fatigue and lowest mood, respectively. Next place the active cathode electrode at P3 and return electrodes at C3, CP5, CP1, PZ, PO3, PO7, and P7 on the neoprene cap. After placing the lower part of each electrode in the selected areas, put the cap on the participant's head and adjust CZ based on prior measurements. Next seat the participant in a comfortable position in a chair. After putting on a neoprene cap on the participant's head, adjust it using the headband until the cap fits snugly. Locate the CZ point and the stimulation zones of the protocol. Then measure the distance between nasion and inion and between the preauricular points using a meter. Locate CZ at the midpoint of both measurements. Separate the hair under each electrode using an elongated object to ensure good contact without disturbing cap placement. Now using a syringe with a plastic tip, introduce sufficient electroconductive gel at the base of each electrode. Turn on the tDCS device and launch the software on the computer. Choose the connection used with the device and select the scan for device option. Press load protocol. Then click on check impedance. If all electrodes appear green, press the play button to start the stimulation program. Next, access the computerized neurorehabilitation platform. Access the plan session and press Start. Present four stimulation activities of seven minutes each sequentially and assign the task to the participant in the calendar. Activate tDCS stimulation by pressing play on the control software for minutes and 20 seconds after starting the neurorehabilitation task. Afterwards apply an adapted questionnaire of sensations related to transcranial electrical stimulation. Ask nine questions about symptoms such as headache, scalp burning, and tingling. Readminister the VAS scale used before the stimulation to evaluate fatigue and mood after intervention. Once the tDCS stimulation program and neurorehabilitation tasks are finished, close the tDCS software. Disconnect the tDCS device. Remove the cable that connects the tDCS with the electrodes. Then remove the cap from the participant's head. In the post-intervention assessment, quantitative changes were observed in six of the 13 tests administered, four of which are directly related to neglect. Clinical improvement was observed in the specific hemispatial neglect tests. On the other hand, negative changes were observed in other attentional tasks.