[Central visual fields in pure alexia "without hemianopsia"--visual dysfunction in the right hemifield, and alexia...

Following a left occipito-temporal subcortical hematoma, a 57-year-old, right-handed man developed pure alexia that was more prominent in kana words, especially in kana nonwords, than in kanji letters. Although a kinetic perimetry with a Goldmann perimeter showed his visual fields to be full, a static perimetry with a Humphrey visual field analyzer disclosed decreased visual sensitivity in the right visual field in its central 30 degrees. In addition, a tachnistoscopic examination with Landolt rings revealed his visual acuity (the ability of two points discrimination) to have decreased in the right half of his central visual filed in its 3 degrees. In the right central vision, he was unable to recognize the letters, pictures or colors presented by the tachistoscope. Concerning the reading, the more letters in kana words or the higher the number of strokes in kanji letters, the more difficulty he experienced in orally reading both kana and kanji. On the contrary, in the left central vision, kanji reading was not so affected by an increased number of strokes as the kana-word reading which became difficult when the number of the letters increased. CT scan showed subcortical hematoma in the left occipitotemporal region. Magnetic resonance imaging 3 months after onset revealed a localized injury in the region between the left postero-inferior temporal lobe and the infero-lateral occipital lobe, including the fusiform gyrus. None of the splenium, the lingual gyrus or the optic area were affected. The spared structures also included the angular gyrus, the Wernicke area and their subcortical white matter.(ABSTRACT TRUNCATED AT 250 WORDS)