Transcranial direct-current stimulation allows patients in a minimally conscious state to recover cognitive and motor skills, University of Liège researchers have shown.
The simple, safe and relatively low-cost technique could offer clinicians a new way to help these patients recover, even several years after their coma. The positive effects however, appear to be temporary at this point in the research.
It would appear that a brain stimulation technique, transcranial direct-current stimulation (tDCS), can help improve clinical responses in patients who have been in a minimally conscious state for several weeks or years, according to research published in Neurology, the medical journal of the American Academy of Neurology.
This very simple system is described by Belgian researchers from the Coma Science Group at the University of Liège, led by Steven Laureys, Director of Research, FNRS, Cyclotron Research Centre and Neurology Department, University Hospital of Liège, including the PhD student Aurore Thibaut, physiotherapist and first author of this study.
The interest in tDCS has been growing. It has already been reported in previous studies as improving attention span, working memory and language functions.
For this reason, the researchers wanted to study the benefits of tDCS in severely brain-damaged patients with a disorder of consciousness after a traumatic brain injury or cardiac arrest.
Twenty-minute stimulations were carried out on 55 patients, half of whom were patients in a minimally conscious state. A clinical improvement was reported in 43% of patients in a minimally conscious state. Aurore Thibaut explains:
“These results are all the more impressive because they can occur in chronic patients, i.e. years after their accident, when their state is often considered as no longer being able to evolve. On the contrary, our study shows that the state of consciousness in severely brain-damaged patients can improve following short cortical stimulation. However, this improvement is only temporary and patients return to their initial state after several hours”.
The researchers are now working on the effect of long-term stimulations to prolong and maintain the benefits of these electrical stimulations on the brain.
Professor Steven Laureys:
“The ease of use and the low cost of this new technique make it a good candidate for rehabilitation in daily clinical practice in order to stimulate the recovery of patients who survive a coma. But also in the chronic stage to improve the evolution in patients in a minimally conscious state.”
A. Thibaut, M.-A. Bruno, D. Ledoux, A. Demertzi, S. Laureys.
tDCS in patients with disorders of consciousness: Sham-controlled randomized double-blind study.
Neurology, 2014; DOI: 10.1212/WNL.0000000000000260
Top Photo: The transcranial direct-current stimulation technique used in this study involves placing two electrodes on the patient’s head: one on the left front side (red) and one on the right side on the temple (black). The electric field induced in the grey matter is shown in yellow. This electrical stimulation helps improve the level of consciousness in some post-coma patients. Credit: © Coma Science Group ULg/CHU