Neuroimaging findings in a patient recovering from global alexia to spelling dyslexia.

The authors report findings in a 67-year-old right-handed man who had an ischemic infarct in the territory of the left posterior cerebral artery. The clinical manifestation consisted mainly of total alexia without agraphia. The patient gradually recovered, subsequently showing the syndrome of spelling dyslexia. Cerebral MR-images revealed a circumscript infarction of medial and basal parts of left temporal lobe. In the acute stage [99mTc]HM-PAO SPECT was characterized by a diminished uptake in the definitely infarcted area and hyperfixation in the region of the left forceps major. Because high retention of HM-PAO indicates potentially salvageable tissue after an ischemic event, the depicted area might be correlated with the recovery of function. Thus, the authors' neuroimaging data give further support to the assumption that the left forceps major is a critical area for global alexia, whereas spelling dyslexia is due to involvement of the left medio-basal temporal lobe.