Agraphia in Mobile Text Messages in a Case of Amyotrophic Lateral Sclerosis with Frontotemporal Dementia

摘要

We herein describe the case of a woman with amyotrophic lateral sclerosis (ALS) showing errors in her choice of Japanese kana characters in her mobile text messages and agraphia of the kana in her handwriting in spite of the absence of weakness, ataxia, or apraxia of her hands. Magnetic resonance imaging showed the atrophy of the frontal lobes. Single-photon emission computed tomography revealed hypoperfusion of the frontal lobes including Exner's area. Although patients with bulbar-onset ALS have been reported to show agraphia of handwriting, in this case the basis of her agraphia might have been the disturbance of the pathway converting phones to graphemes in series, by which errors of spelling or writing would appear in any modality of output.