No universally successful therapy exists that promotes recovery of motor function after a
stroke, the main cause of long-term disability among adults.
The purpose of this study is to develop strategies to improve recovery of lost motor
function. It will combine motor skills training with a brain-stimulating technique called
transcranial direct current stimulation (tDCS).
Healthy adult volunteers and adult stroke patients will be enrolled in this study.
Participants will come to NIH for a clinical and neurological exam, and, if necessary, an
MRI [magnetic resonance imaging] examination. Participants will return for 4 sessions; each
lasting approximately 3 hours. The first will be a practice session during which
participants will become familiar with the motor skills required of them in this study, such
as performing finger movements on a keyboard, pinching, tapping, making wrist movements, and
lifting small items. In sessions 2 and 3, participants will perform the motor skills they
practiced in session 1 while receiving tDCS. During session 4, they will receive tDCS only,
with no performance of motor skills.
During tDCS, investigators will place electrodes with a gel on participants' heads and pass
the tDCS current between these two electrodes. tDCS is a painless procedure.
Participants will receive up to $420 in compensation for their involvement in this study.
There is no universally accepted strategy to promote recovery of motor function after
chronic stroke, the main cause of long-term disability among adults. It is desirable to
develop strategies to accelerate motor learning in this patient group. Previous studies in
healthy volunteers demonstrated that cortical stimulation in association with training leads
to improvements of motor learning and use-dependent plasticity. The purpose of this protocol
is to apply a painless stimulation technique to the motor cortex of the affected hemisphere
of patients with subcortical stroke (transcranial DC stimulation, tDCS) to test the
hypothesis that tDCS of the motor cortex of the affected hemisphere in association with
motor training will improve motor learning of a finger sequence in the paretic hand.
Furthermore, recent studies have demonstrated that the unaffected hemisphere exerts
abnormally high inhibitory influence over the affected hemisphere. This abnormality might
adversely influence motor recovery. Therefore a further purpose of the study is to apply
tDCS to the unaffected hemisphere to test the hypothesis that reduction of the inhibitory
influence of the unaffected hemisphere over the affected in association with motor training
will improve motor learning.
This technique has been so far applied in several hundred subjects worldwide in the absence
of undesirable side effects reported to date.
We plan to study patients with chronic strokes and healthy age- and gender matched normal
volunteers. Primary outcome measure will be the number of correct keyboard piano sequences
played in a specific time-period (30 seconds). Secondary outcome measures are speed of
tapping with only one finger; simple reaction times; pinch force; and a functional measure
of activities of daily life (ADL): Jebsen-Tailor-Test. To better understand the mechanisms
underlying the proposed behavioral gains, we will use TMS to identify changes in
- INCLUSION CRITERIA:
We will include patients with thromboembolic non-hemorrhagic hemispheric lesions at least
3 months after the stroke.
We will choose Patients who initially had a severe motor paresis (below MRC grade 2),
which subsequently recovered to the point that they have a residual motor deficit but can
perform the required tasks. Assessment of the initial functional state will be taken
either from patient report or medical records.
As the control group, we will include age- and gender matched Normal Volunteers with
matched non-dominant/dominant hand (to the affected hand of the stroke patients).
Patients with more than one stroke in the medical cerebral artery territory.
Patients with bilateral motor impairment.
Patients with cerebellar or brainstem lesions.
Patients or Normal Volunteers unable to perform the task (wrist or elbow flexion at least
MRC grade 2).
Patients or Normal Volunteers with severe alcohol or drug abuse, psychiatric illness like
severe depression, poor motivational capacity, or severe language disturbances,
particularly of receptive nature or with serious cognitive deficits (defined as equivalent
to a mini-mental state exam score of 23 or less).
Patients or Normal Volunteers with history of severe uncontrolled medical problems (e.g.
cardiovascular disease, severe rheumatoid arthritis, active joint deformity of arthritic
origin, active cancer or renal disease, any kind of end-stage pulmonary or cardiovascular
disease, or a deteriorated condition due to age, uncontrolled epilepsy or others).
Patients or Normal Volunteers with increased intracranial pressure as evaluated by
Patients or Normal Volunteers with unstable cardiac arrhythmia.
Patients or Normal Volunteers with h/o hyperthyroidism or individuals receiving drugs
acting primarily on the central nervous system.
Patients and Normal Volunteers with more than moderate to severe microangiopathy,
polyneuropathy, diabetes mellitus, or ischemic peripheral disease.
Patients or Normal Volunteers which are or which have been professional piano players.