Transcranial Direct Current Stimulation (tDCS) and Task-Specific Practice for Post-stroke Neglect

Recruiting

Phase 1 Results N/A

Trial Description

The purpose of this study is to test the effects of three different rehabilitation training sessions that combine non-invasive brain stimulation (transcranial direct current stimulation, tDCS) with arm rehabilitation training (repetitive task-specific practice, RTP) for individuals with unilateral spatial neglect following stroke. This study is designed to determine the effects of tDCS + RTP on the excitability in the brain, attention to the affected side, and arm movement ability.

Detailed Description

Unilateral neglect (neglect) is common after stroke and is characterized by an inattention to one side of the body or environment. There is growing evidence that disconnections to fronto-parietal neural networks in the lesioned hemisphere not only cause neglect, but also cause these same networks to be hyperexcited in the non-lesioned hemisphere. Individuals with neglect typically experience motor impairments also since the regions of the brain that control attention also control movement.
Transcranial direct current stimulation (tDCS) when paired with repetitive task-specific practice (RTP) has the potential to modulate cortical activity (fronto-parietal networks) and facilitate motor and attentional recovery for individuals with neglect since tDCS can modulate the excitability of targeted cortical regions. tDCS is a form on non-invasive brain stimulation and RTP is the gold standard post-stroke motor recovery intervention.
It is particularly important investigators examine the effect of RTP + tDCS on cortical modulation in order to understand the underlying mechanism of the intervention and determine whether RTP+ tDCS (parietal or primary motor cortex [M1]) promotes greater neural modulation than RTP alone. Traditionally, electrodes are placed on M1 to facilitate motor recovery and on the parietal lobe to facilitate attentional recovery, however this intervention is designed to target each of these impairments (motor, attention) and enhance cortical modulation of fronto-parietal networks. Therefore, investigators must also determine the optimal electrode montage and placement for pairing tDCS with RTP for individuals with neglect.
The purpose of the proposed pilot project is to examine the effects of transcranial direct current stimulation (tDCS) paired with repetitive task-specific practice (RTP) on modulation of fronto-parietal network connectivity (measured by transcranial magnetic stimulation [TMS]), motor impairment (measured with kinematic assessment), and attentional impairment (measured with Behavioral Inattention Test) among individuals with unilateral neglect and hemiparesis post stroke. This three day cross-over design study will examine the optimal electrode placement and montage using 3 conditions: (1) tDCS to parietal lobe + RTP (2) tDCS to primary motor cortex + RTP (3) sham tDCS + RTP.

Conditions

Interventions

  • TDCS Device
    Intervention Desc: tDCS is a form of noninvasive brain stimulation. Electrodes are placed on the scalp (parietal or primary motor cortex) and deliver a low level of direct current (2mA). tDCS will be delivered for 30 minutes in conjunction with repetitive task-specific practice for the arm/hand.
    ARM 1: Kind: Experimental
    Label: Parietal tDCS plus RTP
    Description: Single session of bilateral parietal tDCS (2.0 mA for 30 minutes) paired with repetitive task-specific practice (RTP).
    ARM 2: Kind: Experimental
    Label: Primary motor cortex tDCS plus RTP
    Description: Single session of bilateral primary motor cortex tDCS (2.0 mA for 30 minutes) paired with repetitive task-specific practice (RTP)
  • Sham tDCS Device
    Intervention Desc: Sham tDCS will be delivered for 30 minutes in conjunction with repetitive task-specific practice for the arm/hand.
    ARM 1: Kind: Experimental
    Label: Sham tDCS plus RTP
    Description: Single session of sham tDCS (for 30 minutes) paired with repetitive task-specific practice (RTP)
  • Repetitive task-specific practice (RTP) Behavioral
    Other Names: task practice
    Intervention Desc: Participants will practice using their paretic arm/hand to complete functional movements during each (3) 30 minute training session.
    ARM 1: Kind: Experimental
    Label: Parietal tDCS plus RTP
    Description: Single session of bilateral parietal tDCS (2.0 mA for 30 minutes) paired with repetitive task-specific practice (RTP).
    ARM 2: Kind: Experimental
    Label: Primary motor cortex tDCS plus RTP
    Description: Single session of bilateral primary motor cortex tDCS (2.0 mA for 30 minutes) paired with repetitive task-specific practice (RTP)
    ARM 3: Kind: Experimental
    Label: Sham tDCS plus RTP
    Description: Single session of sham tDCS (for 30 minutes) paired with repetitive task-specific practice (RTP)

Trial Design

  • Allocation: Randomized
  • Masking: Double Blind (Subject, Outcomes Assessor)
  • Purpose: Treatment
  • Intervention: Crossover Assignment

Outcomes

Type Measure Time Frame Safety Issue
Primary Change in excitability of fronto-parietal connectivity Participants will be assessed at baseline and 30 minutes later (immediately following intervention session). No
Secondary Change in kinematics Participants will be assessed at baseline and 1 hour later (immediately following intervention session). No
Secondary Change on Behavioral Inattention Test Participants will be assessed at baseline and 1.5 hours later (immediately following intervention session). No

Sponsors