Occipital stroke is associated with homonymous visual field defects (occurring on one side of the visual field). Despite spontaneous recovery, some degree of defect is often permanent. Currently, no treatment exists for such visual field defects.The purpose of this study is to test the efficacy of a type of electrical brain stimulation method, transcranial alternating current stimulation, in reducing these type of visual field defects in their chronic stage.
- Active tACS using DC-Stimulator MC Device
Intervention Desc: Transcranial alternating current stimulation (tACS) is administered using DC-Stimulator MC (NeuroConn GmbH, Ilmenau Germany). Stimulation is administered through two 5 cm2 saline-soaked electrodes placed in the Fpz position and on the right arm. Stimulation will consist of short blocks, during which stimulation frequency will be ramped up to 30Hz with maximum current of 1.5mA. Stimulation will be administered for 20 minutes on 10 consecutive weekdays. ARM 1: Kind: Experimental Label: Active tACS using DC-Stimulator MC Description: 15 to 30 patients will be randomized to the arm receiving the active transcranial alternating current stimulation (tACS) treatment using DC-Stimulator MC.
- Sham stimulation using DC-Stimulator MC Device
Intervention Desc: Patients in the sham group will undergo the same preparations as the treatment group. This includes using an identical electrode placement and session duration as for the experimental arm. In order to create the effect of phosphenes, one 5Hz current burst per minute will be administered using the individual phosphene threshold of the patient. This is not expected to have therapeutic effects. ARM 1: Kind: Experimental Label: Sham stimulation using DC-Stimulator MC Description: The same number of patients as in the active arm, 15 to 30, will be randomized to receive sham stimulation using DC-Stimulator MC.
- Allocation: Randomized
- Masking: Double Blind (Subject, Outcomes Assessor)
- Purpose: Treatment
- Endpoint: Efficacy Study
- Intervention: Parallel Assignment
|Type||Measure||Time Frame||Safety Issue|
|Primary||Improved detection in the visual field defined as the percentage change of the stimulus detection rate in High-resolution perimetry (HRP)||Change between 3-7 days pre-treatment, at 3-7 days post-treatment, and at 2 months post-treatment||No|
|Secondary||The change in extent of visual fields in standard automated perimetry||Change between 3-7 days pre-treatment, at 3-7 days post-treatment, and at 2 months post-treatment||No|