Thalamic alexia with agraphia

Abstract

Alexia with agraphia is defined as an acquired impairment affecting reading and writing ability. It can be associated with aphasia, but can also occur as an isolated entity. This impairment has classically been associated with a left angular gyrus lesion In the present study, we describe a case involving a patient who developed alexia with agraphia and other cognitive deficits after a thalamic hemorrhage. In addition, we discuss potential mechanisms of this cortical dysfunction syndrome caused by subcortical injury. We examined a patient who presented with alexia with agraphia and other cognitive deficits due to a hemorrhage in the left thalamus. Neuropsychological evaluation showed attention, executive function, arithmetic and memory impairments. In addition, language tests revealed severe alexia with agraphia in the absence of aphasia. Imaging studies disclosed an old thalamic hemorrhage involving the anterior, dorsomedial and pulvinar nuclei. Tractography revealed asymmetric thalamocortical radiations in the parietal region (left <right), and single photon emission computed tomography demonstrated hypoperfusion in the left thalamus that extended to the frontal and parietal cortices. Cortical cognitive deficits, including alexia with agraphia, may occur as the result of thalamic lesions. The probable mechanism is a diaschisis phenomenon involving thalamic tract disconnections.

Brainstem arteriovenous malformation presenting with dyspraxic handwriting in a young girl

“…The thalamic involvement in this girl brings us back to the few reported cases of adult patients with isolated thalamic agraphia with impaired grapheme formation and micrographia due to a lesion in ventral and ventroposterolateral nuclei in the left thalamus or with pure agraphia or with alexia and agraphia due to left thalamic bleeding [2][3][4]. All these authors suggest a potential role of the thalamus in writing disorders with secondary negative effect of the lesion on the function of left cerebral cortex.…”

Agraphia with Mild Alexia Following Left Thalamic Infarction

“…The LP is connected to the PP and regulates its function ( 1 ). Thus, the thalamic agraphia and alexia ( 2 ) observed in this case was likely caused by damage to the LP, resulting in a reduced PP function.…”