Progressive asymmetric apraxic agraphia

Abstract

Background/objectives: Patients with apraxic agraphia cannot correctly form the letters needed to write words but can correctly spell words orally. Apraxic agraphia (AA) is often associated with ideomotor apraxia and most commonly induced by stroke, but can be associated with degenerative diseases. In degenerative diseases, asymmetrical apraxic agraphia (AAA) has rarely been reported as one of the presenting features. The purpose of this report is to describe a case series of 3 patients who presented with an AAA, and also to elucidate some of the cognitive mechanisms of this disorder.

Methods/results: These patients, who were not aphasic or alexic, developed agraphia as one of their earliest reported symptoms. They also demonstrated an asymmetrical ideomotor apraxia. Their agraphia was characterized by the inability to form letters, with the preserved ability to orally spell. To learn if this disorder was being caused by a loss of spatial-movement representations versus an impairment of implementation, one patient was asked to determine if gestures made by the examiner were correct or incorrect, and also to image the structure of letters. He performed poorly on both these tests and he also demonstrated an asymmetrical agraphesthesia.

Conclusions: These patients' AAA might be the beginning of the corticobasal degeneration syndrome, but future studies will have to examine the brain pathology associated with AAA. Our patient's poor performance on pantomime recognition and imagery suggests that his apraxia is related to a deterioration of his graphemic and transitive spatial movement representations. The recognition of numbers written on the hand with eyes closed might also depend on having intact movement representations and his asymmetrical agraphesthesia might also be related to his AAA.