Long-term recovery from acquired childhood aphasia and changes of cerebral blood flow

In this study, we investigated the mechanism of functional reorganization underlying long-term functional recovery from acquired childhood aphasia. We followed a 9-year-old boy with aphasia from 3 months to 10 years and 5 months after his stroke. The patient's language ability was assessed five times by the Standard Language Test of Aphasia (SLTA) and regional cerebral blood flow (rCBF) was measured four times with 99mTc-ECD and a fully automated quantitative image analysis system. The patient showed continuous improvement of language throughout this period. Overall rCBF peaked at the time of the 2nd measurement (at the age of 12 years and 2 months) and then gradually decreased to the 4th measurement (at the age of 20 years and 2 months). However, there were several patterns of significant relative dominance of rCBF in one cerebral hemisphere compared with the other hemisphere. The Broca and supplementary motor areas showed consistent right hemisphere dominance throughout the study period, but Wernicke's area showed left hemisphere dominance in the early stage (comparison between the 1st and 2nd measurements or the 2nd and 3rd measurements), followed by right hemisphere dominance in the late stage (comparison between the 3rd and 4th measurements). In the primary auditory area, right hemisphere dominance was only seen in the late stage (comparison between the 3rd and 4th measurements). These findings suggest that both hemispheres are involved in the long-term recovery of children from aphasia, but the location of functional reorganization varies depending on the ROIs studied and the stage after the onset.