Letter assembling and handwriting share a common allographic code

A patient is reported who presented with severe agraphia encompassing handwriting, letter assembling and oral spelling disorders. Her writing problems could not be accounted for in terms of apraxia, alexia, aphasia, visual imagery, perceptual or intellectual deficits. She made phonologically plausible errors in all writing modalities, but showed letter substitutions or letter omissions only in handwriting and letter assembling tasks. A common allographic mechanism is postulated which specifies case and style information for all visually based spelling tasks. The pattern of the patient's performances is interpreted assuming a deficit at the output orthographic lexicon, which accounts for phonologically plausible errors, coupled with an allographic disorder thought to be responsible for errors occurring at single letter level. (C) 2001 Elsevier Science Ltd. All rights reserved.