Alexia without agraphia

Abstract

Four cases of alexia without agraphia were studied by 99m-technetium pertechnetate brain scan. Two types of increased uptake were seen. One was of the triangular type near the midline in the posterior view, said to characterize an infarction in the distribution area of the posterior cerebral artery. This was associated with the well-known clinical picture of alexia without agraphia accompanied by hemianopia and color-naming defect, and was confirmed by postmortem examination. The other type of pathologic isotope uptake, observed in three patients, was more laterally placed, in the basal part of the left occipital lobe, and did not reach the midline. In these cases the alexia was transient and not associated with color-naming defects.

Alexia without agraphia

“…In reported cases of alexia without agraphia, infarction in the distribution of the left posterior cerebral artery (PCA) (Fig. 3 a) it the most common pathologic process [13][14][15]. The left visual cortex is supplied directly by the left PCA and compromise of this artery therefore results in varying degrees of infarction of this region, destroying input from this area to the angular gyrus and causing the right homonymous hemianopia commonly associated with this syndrome.…”

“…While most cases of this syndrome have been reported in the setting of ischemic or thromboembolic disease [13][14][15][17][18][19], cases associated with transtentorial herniation [20], migraine [21], intra-and extraaxial left occipital region neoplasms [4,[14][15][16]22] and surgery for a left occipital lobe vascular malformation [23] have also been reported, as have cases in the setting of carbon monoxide poisoning [24] and cerebral abscess [25]. Theoretically, any process (e. g. multiple metastases, traumatic shear hemorrhages, demyelinating plaques, etc.)…”

Reversible Alexia Without Agraphia due to Migraine

“…Nuclide brain scans in these patients show uptake in a triangular region adjacent to the midiine with the base on the transverse sinus. 8 The pattern of neurologic deficits reported by this patient corresponds to vascular territories of branches of the posterior cerebral artery.11·14·15 With onset of the hemianopia the calcarine branches of the patient's left middle occipital artery were prob¬ ably affected. As he did not attempt other tasks such as reading at that time, the proximal extent of the vas¬ cular deficit cannot be determined.…”

Pure alexia after damage to the right fusiform gyrus in a right-handed male

“…# memory deficits, and homonymous hemianopia [7]. A brain disorder (usually posterior cerebral artery stroke) is commonly found in the inferior occipito-temporal region of the left hemisphere, including the fusiform and parahippocampal gyri.…”