Alexia without agraphia (clinicotomographic correlation)

: Two cases of alexia without agraphia, one due to a cerebrovascular accident which improved spontaneously and the other in a cerebral abscess partially recovered after surgical treatment are presented. Both were anatomically verified by computed tomography. The second was also verified at surgery. A small well localized lesion of the fusiform and lingual gyri in the dominant hemisphere can lead to alexia without agraphia. The lack of involvement of the optic radiation and calcarine fissure explain the abscence of visual field defects and hence the purest type of this syndrome as shown in our first case. The involvement of the splenium of the corpus calosus and related forceps majors seems essential for a long lasting reading defect. The integrity of the dorsal or superior splenium is responsible for the abscence of the color warning defect found on about 30% of the cases of pure word blindness. The severity and ultimate progression of the alexia will depend not only upon the extension of the dominant occipital lesion but of its association with the damage of other possible pathways. A slowly growing and potentially treatable expanding lesion, as in our second case, can also produce an almost pure form of the syndrome. It appears to us that the wider use of CT will allow on the near future will lead to a better knowledge of the anatomical lesions and a better understanding of this fascinating syndrome.