Affiliations: Department of Neurology, Mitsui Memorial Hospital,
Tokyo, Japan | Department of Neurology, Graduate School of Medicine,
University of Tokyo, Tokyo, Japan | Department of Radiology, Graduate School of Medicine,
University of Tokyo, Tokyo, Japan
Note: [] Corresponding author: Yasuhisa Sakurai, MD, PhD., Department of
Neurology, Mitsui Memorial Hospital, 1, Kanda-Izumi-cho, Chiyoda-ku, Tokyo
101-8643, Japan. Tel.: +81 3 3862 9111; Fax: +81 3 5687 9765; E-mail:
[email protected]
Abstract: Objective: To characterize various dysgraphic symptoms in parietal
agraphia. Method: We examined the writing impairments of four dysgraphia
patients from parietal lobe lesions using a special writing test with 100
character kanji (Japanese morphograms) and their kana (Japanese phonetic
writing) transcriptions, and related the test performance to a lesion site. Results: Patients 1 and 2 had postcentral gyrus lesions and showed
character distortion and tactile agnosia, with patient 1 also having limb
apraxia. Patients 3 and 4 had superior parietal lobule lesions and features
characteristic of apraxic agraphia (grapheme deformity and a writing stroke
sequence disorder) and character imagery deficits (impaired character recall).
Agraphia with impaired character recall and abnormal grapheme formation were
more pronounced in patient 4, in whom the lesion extended to the inferior
parietal, superior occipital and precuneus gyri. Conclusion: The present findings and a review of the literature
suggest that: (i) a postcentral gyrus lesion can yield graphemic distortion
(somesthetic dysgraphia), (ii) abnormal grapheme formation and impaired
character recall are associated with lesions surrounding the intraparietal
sulcus, the symptom being more severe with the involvement of the inferior
parietal, superior occipital and precuneus gyri, (iii) disordered writing
stroke sequences are caused by a damaged anterior intraparietal area.
Keywords: Apraxic agraphia, parietal pure agraphia, intraparietal sulcus, limb apraxia, somatosensory area
