Acquired dyslexia after stroke in the prereading stage: a single case treatment study with f MRI

The authors report a treatment study of a child (CK) who suffered a left-hemisphere stroke at age 6.3 years, a few months before beginning school. Despite complete recovery of spoken language abilities, CK failed to acquire written language abilities. Neurolinguistic assessment 2 years after the stroke revealed marked impairments in working memory, deficits in acquiring a sublexical reading strategy, and a very rudimentary orthographic network. Functional imaging demonstrated activation in posterior language areas during reading of familiar words while the attempt to read unfamiliar words activated peri- and contralesional structures of the anterior language areas. It was assumed that despite sufficient neural plasticity, the acquisition of a sublexical reading strategy was prevented by severe working memory deficits. Therefore, a specific treatment intervention was developed, choosing a compensatory strategy for reading remediation. Reading development was monitored over three months before and three months after an intensive training was conducted. Data showed significant gains in reading performance only after the specific intervention. These gains remained stable in a catamnesis 2 years later.