Reading Lessons May Change Adult Dyslexics' Brains
Wed Nov 3, 2004
NEW YORK (Reuters Health) - Remedial reading lessons can not only help adults with dyslexia build their reading skills, but may also spur changes in brain activity associated with the condition, according to a small study.
Past research has already found that when dyslexic children improve with remedial programs, there seems to be an accompanying "normalization" of activity in brain regions linked to reading.
Now the new findings, published in the journal Neuron, indicate that the same brain adaptation is also possible in adults with the disorder.
Researchers found that men and women with dyslexia who went through eight weeks of phonics-based instruction showed increases in brain activity that corresponded to gains in reading skills.
Phonics-based training focuses on teaching people to associate letters with the sounds they represent, as opposed to learning whole words as single units.
Despite having normal intelligence, people with dyslexia have trouble recognizing and processing written language, causing them difficulties with reading, writing and spelling. The exact cause of the learning disability is unclear, but imaging studies of the dyslexic brain have revealed reduced activity in areas involved in processing the sounds of speech and associating these sounds with letters and words.
At the outset of the new study, Dr. Guinevere F. Eden of Georgetown University in Washington, D.C., and her colleagues found such brain differences between a group of dyslexic adults and a group without the learning disability.
Using the brain-imaging technique called functional MRI, the researchers found that dyslexic individuals had lower activity in a brain region called the left inferior parietal cortex during a task that measured their ability to identify and process sounds of speech. For the task, study participants had to listen to a word, then repeat it, dropping the first letter-saying, for example, "at" in response to hearing the word "cat."
After finding these brain differences between the groups, the researchers had half of the 19 adults with dyslexia undergo phonics-based training. After eight weeks of lessons, Eden and her colleagues report, these men and women not only showed gains in reading skills, but also in activity in the left inferior parietal cortex.
The researchers also discovered a shift in activity in certain areas of the right side of the brain -- similar to the "compensatory" mechanism that has been found in the brains of adults who've had rehabilitation for reading problems caused by a stroke.
"Together," Eden and her colleagues conclude, "these findings provide evidence that dyslexic adults are not, as may have been assumed, unable to profit from remedial practice."
In addition, they note, understanding what happens in the brain following remedial reading instruction may allow for the development of more-effective therapies for adults with the learning disability.
SOURCE: Neuron, October 28, 2004.