title: Dystypia: isolated typing impairment without aphasia, apraxia or visuospatial impairment.
abstract: We report a 60-year-old right-handed Japanese man who showed an isolated persistent typing impairment without aphasia, agraphia, apraxia or any other neuropsychological deficit. We coined the term 'dystypia' for this peculiar neuropsychological manifestation. The symptom was caused by an infarction in the left frontal lobe involving the foot of the second frontal convolution and the frontal operculum. The patient's typing impairment was not attributable to a disturbance of the linguistic process, since he had no aphasia or agraphia. The impairment was not attributable to the impairment of the motor execution process either, since he had no apraxia. Thus, his typing impairment was deduced to be based on a disturbance of the intermediate process where the linguistic phonological information is converted into the corresponding performance. We hypothesized that there is a specific process for typing which branches from the motor programming process presented in neurolinguistic models. The foot of the left second frontal convolution and the operculum may play an important role in the manifestation of 'dystypia'.
authors.affiliation: Cerebrovascular Division, Department of Internal Medicine, National Cardiovascular Center, Suita, Japan. miotsuki@hsp.ncvc.go.jp
authors.forename: Mika
authors.initials: M
authors.lastname: Otsuki
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Soma
authors.forename: Shoji
authors.initials: S
authors.lastname: Arihiro
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Moriwaki
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Naritomi
mesh_terms: D000381:Agraphia / Q000503:physiopathology; D001037:Aphasia / Q000503:physiopathology; D001072:Apraxias / Q000503:physiopathology; D002544:Cerebral Infarction / Q000503:physiopathology*; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009048:Motor Skills; D009483:Neuropsychological Tests; D013028:Space Perception; D014796:Visual Perception