Non-Invasive Brain Stimulation as an Innovative Treatment for Chronic Neglect Patients

Study Overview
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Brief Summary
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Background Stroke is a leading cause of neurological impairments in language, motor and cognitive functions. Next to traditional stroke treatment, Non-Invasive Brain Stimulation (NIBS) offers the potential to facilitate stroke recovery as a complementary approach. Here, we aim at exploiting the principles of NIBS, specifically transcranial Alternating Current Stimulation (tACS), to promote functional recovery of people with neglect symptoms following stroke. Objective To determine whether neglect training complemented with tACS treatment in chronic stroke patients suffering from neglect improves neglect-related symptoms compared to neglect training with sham stimulation. Study design Double-blind randomized placebo-controlled intervention study. After enrollment and completion of baseline measurements, participants are randomly assigned to either the active tACS group or sham (control) group. Intervention We will combine an evidence based visual scanning training (VST) with 40 minutes of (active or sham) tACS at alpha frequency. The intervention is administered three times a week for a duration of six weeks. Outcomes of the study Performance on standard, conventional neuropsychological tests, as well as on ADL observation scales.

Official Title
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Transcranial Alternating Stimulation in Rehabilitation: a Randomized Controlled Trial in Chronic Stroke Patients With Visuospatial Neglect

Conditions
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Spatial Neglect

Intervention / Treatment
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* Device: Transcranial Alternating Current Stimulation (tACS)
* Behavioral: Visual Scanning Training (VST)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: neurologically objectified stroke; stroke occurred when patient was 18-80 years of age; chronic stroke (>6 months post-stroke onset); sufficient comprehension and communication skills to benefit from training (based on clinical judgement); and a screening containing four neuropsychological tests will be performed to evaluate the current severity of the neglect, since the diagnosis of neglect may have been established months or even years ago in our sample of chronic stroke patients. Exclusion Criteria: currently engaging in cognitive rehabilitation treatment or neglect treatment; physically or mentally unable to participate (based on clinical judgment); hemianopsia (based on clinical judgement); severe communicative disability, as task descriptions need to be understood; local scalp injuries*; eczema on scalp or psoriasis*; diagnosed (neuro)psychiatric or neurodegenerative diseases*; current alcohol and/or drug abuse*; and pregnancy*. due to tACS safety considerations.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Active tACS<br> | Device: Transcranial Alternating Current Stimulation (tACS)<br>* Stimulation frequency and peak-to-peak intensity will be set to 10Hz and 1.5 milliampere (mA), phase offset will be set to 0 and 100 cycles will be used for ramping up. At the start of the neglect training session, the tACS will be started. When the neglect training session is finished, after maximally 40 minutes, the tACS will be switched off.<br>Behavioral: Visual Scanning Training (VST)<br>* The most common treatment for neglect is VST, which is an intensive compensation training (see Dutch guidelines for rehabilitation of neglect: Ten Brink, Van Kessel, & Nijboer, 2017). The aim of this training is to improve visual scanning behavior, that is, to encourage neglect patients to actively and consciously pay attention to stimuli on the contralesional side.<br>|
| Sham Comparator: Sham tACS<br> | Device: Transcranial Alternating Current Stimulation (tACS)<br>* Stimulation frequency and peak-to-peak intensity will be set to 10Hz and 1.5 milliampere (mA), phase offset will be set to 0 and 100 cycles will be used for ramping up. At the start of the neglect training session, the tACS will be started. When the neglect training session is finished, after maximally 40 minutes, the tACS will be switched off.<br>Behavioral: Visual Scanning Training (VST)<br>* The most common treatment for neglect is VST, which is an intensive compensation training (see Dutch guidelines for rehabilitation of neglect: Ten Brink, Van Kessel, & Nijboer, 2017). The aim of this training is to improve visual scanning behavior, that is, to encourage neglect patients to actively and consciously pay attention to stimuli on the contralesional side.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Star Cancellation Task | Quality of search score | Testing will take place before the training (T0; baseline), after the first (T1), ninth (T2), and eighteenth (T3) training session, as well as one week (T4) and three months (T5) after termination of the training. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Computerized Visual Detection Task | Sum of weighted hits | Testing will take place before the training (T0; baseline), after the first (T1), ninth (T2), and eighteenth (T3) training session, as well as one week (T4) and three months (T5) after termination of the training. | 
| McIntosh Line Bisection Task-digitized | Endpoint weightings bias | Testing will take place before the training (T0; baseline), after the first (T1), ninth (T2), and eighteenth (T3) training session, as well as one week (T4) and three months (T5) after termination of the training. | 
| Schenkenberg Line Bisection Task | Relative deviation score | Testing will take place before the training (T0; baseline), after the first (T1), ninth (T2), and eighteenth (T3) training session, as well as one week (T4) and three months (T5) after termination of the training. | 
| Baking Tray Task | Average x-coordinate | Testing will take place before the training (T0; baseline), after the ninth (T2) training session, as well as one week (T4) and three months (T5) after termination of the training. | 
| Catherine Bergego Scale | Total score. The CBS is a 10-item observation scale, and results in a total score of 0 (no neglect) to 30 (severe neglect). | Testing will take place before the training (T0; baseline), after the ninth (T2) training session, as well as one week (T4) and three months (T5) after termination of the training. | 
| Subjective Neglect Questionnaire | Total score. The SNQ is a 19-item questionnaire, and results in a total score of 19 (no reported problems) to 95 (many/frequently reported problems). | Testing will take place before the training (T0; baseline), after the ninth (T2) training session, as well as one week (T4) and three months (T5) after termination of the training. |