Late LTP-like Plasticity Effects of tDCS in Chronic Stroke Patients
Condition: Stroke; Hemiparesis
MeSH terms: Paresis
Study type: Interventional

Summary: 
      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.
    


Intervention name(s): Sham; Conventional Paired tDCS; Conventional Unpaired tDCS; Late LTP-like Plasticity tDCS
Intervention type(s): Device; Device; Device; Device
Intervention description(s): Bihemispheric 1mA Sham protocol: sham - pause - sham; Bihemispheric 1mA Sham protocol: sham - pause - sham Conventional Paired tDCS protocol: 20 minutes tDCS - pause - sham; Bihemispheric 1mA Sham protocol: sham - pause - sham Conventional Unpaired tDCS protocol: 20 minutes tDCS - pause - sham; Bihemispheric 1mA Sham protocol: sham - pause - sham Late LTP-like Plasticity tDCS protocol: 10 minutes tDCS - 25 minutes pause - 10 minutes tDCS
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment