Can non-invasive electrical stimulation of the brain help patients regain a state of consciousness after a coma?
Researchers have shown that transcranial direct-current stimulation allows patients in a minimally conscious state to recover cognitive and motor skills. This simple, safe and relatively low-cost technique could offer clinicians a new way to help these patients recover, even several years after their coma. However, the positive effects appear to be temporary at this stage of 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 the online issue of 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 of tDCS has already been reported in previous studies as improving attention span, working memory and language functions. Consequently, 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. “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”, Aurore Thibaut explains. 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.
For 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.”
tDCS in patients with disorders of consciousness: sham-controlled randomised double blind study, Aurore Thibaut, Marie-Aurélie Bruno, Didier Ledoux, Athena Demertzi, Steven Laureys, Neurology DOI: 10.1212/WNL.0000000000000260, published online 26 February 2014