Stroke patients improve on picture-naming task after stimulation treatment
CHICAGO — A brain zapping technique helps people recover language after a stroke, new research shows. The results may point to a better way for people to relearn how to talk after a brain injury.
“I think this work is very promising,” said cognitive neuroscientist Roi Cohen Kadosh of the University of Oxford. The study, presented April 2 at the annual meeting of Cognitive Neuroscience Society, represents one of the first attempts to successfully apply brain stimulation techniques to a clinical population, he said.
Speech therapist and neuroscientist Jenny Crinion of University College London and collaborators focused on people who had trouble finding the right word after a stroke. Known as anomia, the condition is frustrating, leaving people unable to call the correct word to mind.
Crinion and her colleagues paired a word-training technique with brain stimulation. The training regimen was intense. In the lab and at home, participants studied 150 cards with pictures of one-syllable words of everyday objects: cat, bed, car and so on for a total of about 60 hours over six weeks.
Three days a week, six volunteers came into the lab to receive a type of electrical brain stimulation known as transcranial direct current stimulation. Volunteers received the stimulation, which doesn’t seem to cause pain or any ill effects, while training on the vocabulary words. Seven volunteers received a sham treatment without stimulation.
Stimulation was targeted to Broca’s area in the left side of the brain, a region linked to speech production. The kind of stimulation used in the study is thought to enhance nerve cell activity, though exactly how it works isn’t clear.
Although the study is still in its early stages, initial results look promising, Crinion said. All of the volunteers improved, because they all received the normal word recognition training. But people who also received brain stimulation showed a startling improvement. At the end of the six-week study, the six volunteers receiving stimulation nearly doubled their scores on a picture-naming task, improving by 92 percent. Seven volunteers without brain stimulation improved on average by 56 percent.
This gap persisted after the initial testing, though it diminished in size. Three months out, volunteers who received the stimulation performed 82 percent better than they had performed before treatment, while those receiving sham treatment held steady with a 55 percent improvement. “These are huge effects,” Crinion said. “It’s really encouraging.”
The team doesn’t know whether the improvements will apply to other types of language use, such as carrying on conversations. But some of the patients have noticed improvements in their quality of life, Crinion said. At the conclusion of the therapy period, one man with anomia took the researchers out to celebrate at a pub, and insisted on ordering for the whole group himself.
The researchers hope to add more participants and conduct brain imaging studies to see how brain activity changes as a result of the training and brain stimulation regimen.
J. Crinion. Examining the potential of transcranial direct current stimulation for enhancing speech production in healthy subjects and neurological patients. Cognitive Neuroscience Society meeting, Chicago, April 2, 2012. Abstract available: [Go to]