A team of doctors and scientists in Australia, three of whom have been supported by Foundation NARSAD Grants, have concluded the most thorough test to date of a novel method of increasing the brain’s cognitive abilities. These abilities, which include working memory, processing speed, executive function and reaction time, are degraded in illnesses including schizophrenia and bipolar disorder.
The method, called transcranial direct current stimulation, or tDCS, has already been used to help stroke victims recover, and has been tested on patients with Alzheimer’s and Parkinson’s diseases. As noted by Donel M. Martin, Ph.D., of the University of New South Wales, who has studied tDCS using a 2010 NARSAD Young Investigator Grant, the method “can potentially help the brain to relearn through facilitating local brain activity and inhibiting competing brain regions.”
tDCS is a non-invasive technique in which a very weak direct electrical current is passed through the cerebral cortex via electrodes placed on the scalp. Dr. Martin and colleagues, who included Melissa Green, Ph.D., a 2006 NARSAD Young Investigator Grantee, and Colleen K. Loo, M.D., Ph.D., a 2007 NARSAD Independent Investigator Grantee, tested the cognitive performance of 56 healthy people. The participants each took 10 computer-administered cognitive training sessions. Some received tDCS during the sessions; others did not.
Results, which appeared in the October issue of the International Journal of Neuropsychopharmacology, showed the group that got tDCS stimulation while training performed better than the group that did not. But the improvement lasted only as long as the computer training session; there was no “learning effect” that carried over to subsequent sessions. Improvement was muted when the same groups were tested on a different set of tasks a month later. Nevertheless, the investigators conclude that tDCS, properly administered, “may have a role in enhancing outcomes” that extend beyond treatment sessions themselves.