Researchers from Germany and Australia teamed up to answer an important question. Does electrical stimulation of the brain after stroke change the brain itself? Transcranial direct current stimulation, known as tDCS, is a new non-invasive technique that activates nerve cells in the brain. Interest in the technology is high since it is inexpensive and easy to use, without significant side effects. Improvements have already been seen in stroke patients with aphasia. Aphasia is the loss of the ability to understand speech or express things in words. However, a better understanding of what happens in the brain during and after tDCS could improve its application, personalization, and effectiveness.
Testing tDCS to improve language problems
The researchers recruited six women and ten men that were on average 56 years old. Each had experienced a stroke a year ago or more. The researchers asked the patients to name objects they saw in pictures. Difficulty naming objects is a common problem associated with aphasia. Researchers stimulated the primary motor area of the brain with tDCS. Stroke commonly affects this area of the brain in aphasia patients. During the stimulation, researchers used functional MRI (fMRI) to look at the energy levels in the brain. Patients acted as their controls, receiving both tDCS and a fake therapy without knowing which they were getting. Researchers compared brain scans to a control group that did not receive tDCS, to determine if the new patterns of brain activity tended toward those of healthy individuals.
Results showed that tDCS activated large areas of the brain specifically used for language. Also, the connectivity in the language network improved, which means that the processing of information was enhanced. Despite stimulating the entire motor area of the brain, there was no benefit to movements outside of those pertaining to speech. Researchers noted, in fact, that other regions responsible for high-level functioning became less active. These findings together show that tDCS primarily improves the task performed during activation. When compared to the healthy controls, tDCS appeared to shift the brain activity in stroke patients toward regular patterns. Since patients received no other treatments at the time of testing, researchers attribute the improvements wholly to tDCS.
Overall, the results show that tDCS has real effects on the brain and is not just a placebo treatment! If you are struggling with speech after a stroke, you may wish to inquire about local tDCS research.
The lead author of the original article was Dr. Robert Darkow, Department of Neurology, NeuroCure Clinical Research Center, and Center of Stroke, Berlin, Germany.