Progressive agraphia can be a harbinger of degenerative dementia

By investigating three patients with progressive agraphia, we explored the possibility that this entity is an early sign of degenerative dementia. Initially, these patients complained primarily of difficulties writing Kanji (Japanese morphograms) while other language and cognitive impairments were relatively milder. Impairments in writing Kana (Japanese syllabograms), verbal language, executive function, visuo- and visuospatial cognition and memory were identified by neuropsychological testing. The agraphia was compatible with a peripheral type, based on deficits at the interface between the central letter selection and the graphemic motor execution (Patient 1) or at the stage of central letter selection as well (Patients 2 and 3). Agraphia was generally more prominent, although not exclusive, for Kanji probably because of later acquisition and larger total number of Kanji letters leading to lower frequency of use and familiarity per letter. Concurrent or subsequent emergence of non-fluent aphasia, ideomotor apraxia, executive dysfunction and asymmetric akinetic-rigid syndrome in two patients suggested degenerative processes involving the parietal-occipital-temporal regions, basal ganglia and striato-frontal projections. We propose that progressive agraphia may be one of the early symptoms of degenerative dementia such as corticobasal degeneration.