Reposted from | VCU School of Education News
Neurological Perspectives on Dyslexia
Posted on February 27, 2013 by mdfronti
(Photo: Appearing from left: developmental neurologist Dr. Peter B. Rosenberger, VCU School of Education Ruth Harris Professor of Dyslexia Studies Dr. Paul J. Gerber, and benefactor Ruth S. Harris.)
The way we define and diagnose dyslexia has come a long way in the past 50 years, according to nationally renowned developmental neurologist Peter B. Rosenberger, M.D. He has been studying this common reading disability that affects between 5 and 10 percent of the population.“Dyslexia was originally described as a visionproblem,” Dr. Rosenberger told more than 200 people at a lecture sponsored by the VCU School of Education’s Ruth Harris Endowed Professorship in Dyslexia Studies. “The first description of it in the scientific literature was written by a Scottish ophthalmologist, Dr. James Hinshelwood, and it was thought to represent some disorganization in the way the brain processes information conveyed through the eyes. The current definition is that it is basically a disorder of language, not of vision as first thought.”
Dr. Rosenberger specializes in childhood disorders of cognition. He was a staff physician at Massachusetts General Hospital for 38 years and was founding director of its Learning Disorders Unit before retiring in 2006. He is a fellow of the American Academy of Neurology and the International Academy for Research in Learning Disabilities. His research interests are disorders of language, learning and attention.During the last 30 years, he said researchers in neurology have been interested in whether the brain is different for people with dyslexia from the brain of those who are not dyslexic.
A research finding in the early 1980s, showing that dyslexic brains are symmetrical while normal brains are asymmetrical, led to Dr. Rosenberger’s discovery of a discrepancy between verbal and nonverbal IQ among people whose brains were unusually large on the right side. In a normal, asymmetrical brain, the right side is smaller than the left side. In a symmetrical brain, the right and left sides are the same size.“This would suggest that people with symmetrical brains actually have more cells than those with asymmetrical brains,” said Dr. Rosenberger. “You would think having more cells would be good, but in the normal development of the brain the disappearance of cells is a very important event. So it is normal to have some cells die out, and it could well be that in the symmetrical brain found in dyslexic people, certain cells fail to die out as they should.”
“Dyslexics have trouble making words out of sounds,” said Dr. Rosenberger. “This is known as phonemic awareness, and it is the gold standard for phonological deficits in dyslexics.” He said important factors in diagnosing dyslexia include age, development and family history.
Another important consideration is learning ability. Dr. Rosenberger said dyslexia involves “aptitude deficits,” or the ease at which a skill is acquired. “What you’re trying to put your finger on is the specificity of the problem. You’re trying to show the child is having more trouble with a specific learning challenge than a challenge in general.”
Dr. Rosenberger said dyslexia in children has been addressed through interventions involving remedial instruction that help them acquire the necessary skills for language and reading. Despite poor aptitude, curriculum support can help dyslexic children make steady progress. Poor skills can be addressed with tailored accommodations for classroom tasks and routines.“This is difficult work and it’s easy to get discouraged,” said Dr. Rosenberger. “But we have to resist that temptation because our challenge is to make reading the exciting adventure that it can be both during the school-age years and beyond.”