Please select the eligibility criteria that correspond to the clinical trial below.
Title: N/A
Brief 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.


Options:
A: Inclusion criteria:

* 30 individuals with hemiparesis stemming from a stroke;
* Either gender;
* Able to maintain a standing position without an assistance device for at least 60 seconds;
* Signed statement of written consent.

Exclusion criteria:

* Adverse health condition (beyond hemiparesis) that affects balance;
* Use of medication that can affect balance;
* Positive cutoff point for cognitive deficit (Mini Mental State Examination);
* Illiteracy;
* Wernicke's aphasia;
* Reduced ankle mobility due to history of ankle fracture and use of pins in ankle;
* TA muscle strength less than grade 1;
* Contraindication for tDCS (history of recurrent seizures, recurrent epilepsy and brain tumor in stimulation site);
* Skin infection at tDCS and/or FES site;
* Anesthesia or hyperesthesia at FES site.
B: Inclusion Criteria:

* Patients with clinical diagnosis of acute ischemic stroke (first or recurrent) confirmed by CCT or MRI admitted to the Acute Vascular Unit of HCPA between the first 48 hours of onset of symptoms.
* Patients older than 18 years.
* Patients clinically and hemodynamically stable (SBP 120-220 mmHg, SatO2 up to 92% with or without supplementation, HR between 60 and 100 bmp, body temperature below 38 and RR below 25 bpm).
* Patients are able to react to verbal commands even without being fully alert (Glasgow Scale above 8).
* Prior Rankin until 3
* Motor deficit and / or coordination measured by the NIHSS

Exclusion Criteria:

* Patients with clinical and / or hemodynamic instability
* Patients with hemorrhagic stroke or TIA (transient ischemic attack).
* Patients with progressive neurological disease and acute coronary disease and / or unstable.
C: Inclusion Criteria:

* Chronic (\> 6 months) stroke patient
* Aged 18-79 years
* Motor deficit in the upper limb due to the stroke

Exclusion Criteria:

* Absence of recordable MEPs from the ADM after TMS
* Absence of voluntary movement (Fugl-Meyer \< III)
* Head injury or the presence of intracranial metal or intracranial lesions
* History of cranial irradiation
* History of epilepsy
* Presence of a pacemaker
* Taking anticonvulsant or neuroleptic medication
* Substance abuse
* Inability to understand instructions
* History of psychiatric disorders
D: Inclusion Criteria:

1. First-ever stroke with the onset 10-90 days prior to the enrollment
2. Age: 20-80y
3. With a hemiplegic upper extremity with Brunnstrom stage in I\~IV
4. Able to understand simple orders (1-step orders, such as "raise your hand, touch your head....)
5. Totally independent in activity of daily life before the onset of stroke

Exclusion Criteria:

1. Incompliance to the assessments or interventions due to unstable medical condition, abnormal cognition, or other conditions.
2. Stroke of brainstem or cerebellum
3. Had received craniotomy or ventriculoperitoneal shunting
4. Needs of orthoses in walking before the onset of stroke
5. Had had motor dysfunctions (eg, amputation, cerebral palsy, poliomyelitis or other neuromuscular diseases) before the stroke.
6. Intracranial hemorrhage caused by artereovenous malformation, aneurysm, or tumor
7. Able to walk independently for more than 50 meters.

Answer: C