Late LTP-like Plasticity Effects of tDCS in Chronic Stroke Patients

Completed

Phase N/A Results N/A

Trial Description

Rationale: About 80% of stroke patients suffer motor impairments, but current therapies have limited effects on motor recovery. Therefore, investigating new potential therapeutic approaches is crucial. Transcranial Direct Current Stimulation (tDCS) is a form of non-invasive electrical stimulation where a weak current is applied through electrodes over the scalp. This stimulation is known to (1) induce changes in neuronal excitability -which can last up to one day with late LTP-like plasticity protocols- in a polarity and site-specific manner, and (2) facilitate motor learning and stroke recovery. However, it is unknown how the motor cortex excitability changes that follow tDCS relate to the increase in motor learning and recovery potential. The currently upheld hypothesis is that motor learning needs to be synchronized in time with electrical stimulation (paired stimulation), but recent results from our lab suggest that tDCS also increases skill learning after stimulation has ended (unpaired stimulation). If this is true, tDCS has a much larger therapeutic window and is a more valuable clinical tool than currently believed. Therefore, the investigators want to investigate how late LTP-like plasticity tDCS affects the increase in skill learning normally seen with tDCS when applied 24 hours before training. The outcome of this study can provide important guidelines on effective motor therapy during stroke rehabilitation.
Objective: Identify the effect of late LTP-like plasticity tDCS in chronic stroke patients on skill learning 24 hours later.
Study design: Double-blinded, randomized between-subjects trials. Study population: Chronic stroke patients. Main study parameters/endpoints: The main objective of the study is to determine the effect of late LTP-like plasticity tDCS on skill learning 24 hours later. As a motor learning paradigm, the investigators will use a circuit tracking task which chronic stroke patients perform better if tDCS is applied concurrently. During this task, patients have to trace a cursor over a circuit as fast and accurately as possible by moving a computer mouse. Skill will be quantified by calculating a combined speed/ accuracy score and skill improvement compared to baseline (LI; the learning index) will be compared between the sham, conventional unpaired tDCS, conventional paired tDCS groups and the late LTP-like plasticity tDCS groups.

Conditions

Interventions

  • Sham Device
    Intervention Desc: Bihemispheric 1mA Sham protocol: sham - pause - sham
    ARM 1: Kind: Experimental
    Label: Sham
    Description: Day 1: sham stimulation Day 2: sham stimulation
  • Conventional Paired tDCS Device
    Intervention Desc: Bihemispheric 1mA Sham protocol: sham - pause - sham Conventional Paired tDCS protocol: 20 minutes tDCS - pause - sham
    ARM 1: Kind: Experimental
    Label: Conventional Paired tDCS
    Description: Day 1: sham stimulation Day 2: conventional tDCS
  • Conventional Unpaired tDCS Device
    Intervention Desc: Bihemispheric 1mA Sham protocol: sham - pause - sham Conventional Unpaired tDCS protocol: 20 minutes tDCS - pause - sham
    ARM 1: Kind: Experimental
    Label: Conventional Unpaired tDCS
    Description: Day 1: conventional tDCS Day 2: sham stimulation
  • Late LTP-like Plasticity tDCS Device
    Intervention Desc: Bihemispheric 1mA Sham protocol: sham - pause - sham Late LTP-like Plasticity tDCS protocol: 10 minutes tDCS - 25 minutes pause - 10 minutes tDCS
    ARM 1: Kind: Experimental
    Label: Late LTP-like Plasticity tDCS
    Description: Day 1: late LTP-like Plasticity tDCS Day 2: sham stimulation

Trial Design

  • Allocation: Randomized
  • Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
  • Purpose: Treatment
  • Endpoint: Efficacy Study
  • Intervention: Parallel Assignment

Outcomes

Type Measure Time Frame Safety Issue
Primary Motor Skill Retention Day 9 No
Secondary Maximum Grip Force Day 1 and Day 9 No
Secondary Purdue Pegboard Test Day 1 and Day 9 No

Sponsors