Apraxic agraphia following thalamic damage: Three new cases.

Apraxic agraphia following thalamic damage: Three new cases.
Brain Lang. 2015 Oct 10;150:153-165
Authors: Vandenborre D, van Dun K, Engelborghs S, Mariën P
Abstract
Apraxic agraphia (AA) is a so-called peripheral writing disorder following disruption of the skilled movement plans of writing while the central processes that subserve spelling are intact. It has been observed in a variety of etiologically heterogeneous neurological disorders typically associated with lesions located in the language dominant parietal and frontal region. The condition is characterized by a hesitant, incomplete, imprecise or even illegible graphomotor output. Letter formation cannot be attributed to sensorimotor, extrapyramidal or cerebellar dysfunction affecting the writing limb. Detailed clinical, neurocognitive, neurolinguistic and (functional) neuroimaging characteristics of three unique cases are reported that developed AA following a thalamic stroke. In marked contrast to impaired handwriting, non-handwriting skills, such as oral spelling, were hardly impaired. Quantified Tc-99m ECD SPECT consistently showed a decreased perfusion in the anatomoclinically suspected prefrontal regions. The findings suggest crucial involvement of the anterior (and medial) portion of the left thalamus within the neural network subserving the graphomotor system. Functional neuroimaging findings seem to indicate that AA after focal thalamic damage represents a diaschisis ...

Source: Brain and Language - October 10, 2015 Category: Neurology Authors: Vandenborre D, van Dun K, Engelborghs S, Mariën P Tags: Brain Lang Source Type: research