UCL. Belgium: Each year, nearly
19.000 people in Belgium are victim of a stroke. The majority of
patients who survive a stroke usually continue to suffer from permanent
motor disorders (hemiparesis) or a linguistic handicap (aphasia). A
study of the Department of Neurology of CHU Dinant Godinne - UCL Namur,
reveals an improvement in the efficiency of the brain activity when
patients receive a treatment combining motor revalidation with
non-invasive brain stimulation.
Demonstrated via the technique of functional MRI, these promising results are currently published in Brain, the prestigious British scientific journal dedicated to neurology.
Neuro-rehabilitation (physical therapy, occupational therapy, etc.)
helps hemaparetic stroke patients confronted with loss of motor skills
on one side of their body, to recover some of their motor functions
after a cerebrovascular accident. One of the most promising tracks in
neuro-rehabilitation consists in amplifying the motor learning ability
after a stroke, in other words how to learn (again) how to make
movements with the parts of the human body impacted after a stroke.
Pilot studies have shown at this matter that tDCS (transcranial
direct current stimulation) - a non-invasive and painless cerebral
stimulation method - allowed to modulate the cerebral activity and to
increase the motor performances of patients who have been victim of
stroke. This method consists of applying low voltage electric currents
on the patient’s head by means of electrodes during short periods of
time. In 2012, a first study conducted by the teams of Professors Yves
Vandermeeren and Patrice Laloux allowed to demonstrate that tDCS
amplified the motor learning and the long-term motor memory of the
patient after a stroke. This study was awarded with the Fernand
Depelchin Prize of the Université catholique de Louvain (UCL) and
allowed the CHU Neurology Team to continue its research, in particular via the use of functional Magnetic Resonance Imaging (fMRI) of the brain.
Non-invasive transcranial stimulation
Nineteen hemiparetic stroke patients (with a motor deficit in the
upper limb) participated to this new clinical trial. In order to avoid
study bias, the stimulations were performed in a double-blind,
randomised fashion. Each patient received a real stimulation as well as a
placebo-stimulation during two separate sessions. Because the tDCS was
as good as completely imperceptible, it became impossible for patients
to determine if they received a true or a placebo-stimulation.
During the first stimulation session (real or placebo), the patients
learned how to perform a task with a paralysed hand, combining speed and
accuracy. One week later, they performed the learned task while the
functional MRI scanner recorded their cerebral activity. After one week,
this experience was completely done over again with the other
stimulation (placebo or real).
As in the previous study, the non-invasive cerebral stimulation
amplified the motor learning capacity with the paralyzed hand and the
long-term memory retention in a spectacular way for patients with a
chronic stroke.
Towards new therapeutic approaches
Thanks to functional MRI, this second study demonstrates that the
combination of motor learning and non-invasive cerebral stimulation
improves the efficiency of the cerebral activity. Indeed, one week after
the placebo stimulation, the cerebral activations measured via the
functional MRI was very diffuse. Large cerebral zones were somehow «
recruited » although motor performance was low (poor retention). On the
other hand, one week after real stimulation, the cerebral activation was
focussed on the essential motor zones, almost identical to a person
without stroke-impact although the motor performance was significantly
better (enhanced task retention). In other words, the combination of
motor learning and tDCS reinforced the essential motor zones and this
specific network was reactivated one week after the real intervention.
For thousands of stroke victims, this study opens considerable
perspectives in the domain of neuro-rehabilitation. A better
understanding of the cerebral functioning after a stroke and how
non-invasive cerebral stimulation works will help researchers to develop
the neuro-rehabilitation of the future. The results of this study will
be implemented within the consortium Louvain Bionics inaugurated on November 12 of this year at UCL.