Research Projects Funded by IDA 

Summary: 

Neuroanatomical Analysis of the Cerebellum in Dyslexia

Background: The Orton Brain Bank at the Beth Israel Hospital has proved a fruitful research archive, primarily via the outstanding work of Dr. Albert Galaburda and his colleagues in identifying microscopic abnormalities in the cerebral cortex of the dyslexic specimens, and latterly, in the magnocellular pathways. In independent research, the proposers had established strong evidence of behavioral difficulties in dyslexic children that appeared to suggest that there might also be cerebellar abnormalities in dyslexia. The focus of the proposed research was to replicate the techniques used by Galaburda on the brains in the Orton Collection, but analyzing the cerebellum and related nuclei. Funds were sought from IDA, in order to support the expenses of a postgraduate student (Mr. Andrew Finch), who had been trained in our Department and at London, in carrying out the necessary work in Boston. Funds of $1,000 were awarded to facilitate the research program. Two three-week visits were made over the period from April to November 1996. The necessary statistical analyses and report writing have taken place over the following months. Results In brief, the first visit studied the inferior olive and dentate nuclei (input and output nuclei to the cerebellum). Statistical analyses indicated differences in mean cell size distribution in the inferior olive, with the dyslexic brains having more large cells and fewer small cells. Smaller differences were found in the dentate, with the dyslexic cells showing greater variability rather than difference in mean size. The second visit studies cerebellar cortex, in particular the Purkinje cells. Clear differences were found, with the dyslexic brains again showing greater mean cell size. The magnitude of the differences found was as great as that found by Galaburda and his colleagues in their studies of other regions of the brain. We conclude that the studies have revealed interesting evidence of cerebellar abnormalities in dyslexic brains. We believe that this evidence, in conjunction from other behavioral and neurophysiological evidence established by ourselves and by many other researchers, provides important information that will lead to a better understanding of the underlying causes of dyslexia.