A study of dysgraphia of Chinese characters in a patient with semantic dementia

Abstract

Objective To investigate the clinical features of Chinese dysgraphia and then probe into its mechanisms in a patient with semantic dementia(SD). Methods The patient with SD finished the writing part of the Aphasia Battery of Chinese (Aphasia Battery of Chinese, ABC) and the Chinese agraphia battery (Chinese agraphia battery, CAB) in addition to a series of other neuropsychological tests. Results (1) On the Wechsler Adult intelligence scale, the patient performed poorly on information and vocabulary with scores of 6/29 and 8/80, respectively. He spoke out only 11 names totally on the category fluency test within 1 minute, while 25 names or more than were normal. Semantic features test showed he made 37 right answers of 60 questions, with scores of 8/20 on category, 7/20 on function and 8/20 on nature features.(2)The writing disorder exhibited Chinese aphasia agraphia with obvious difficulty in forming characters, wrong characters of the same pronunciation or the same form or unrelated errors, and grammatical impairments. Its damage from serious to light occurred in picture writing(6/40), writing sentences to convey meaning(1/10), dictation(11/40) and automatic writing(35/40). The transcription was relatively preserved (40/40). (3)He scored 20 and 19 points on MMSE and MoCA. Executive function was damaged significantly, while recent memory was preserved relatively. Conclusion The patient with SD shows an impoverished store of general knowledge and poor comprehension of single-word. The nature of SD's dysgraphia presents Chinese aphasia agraphia, undoubtedly due to progressive deterioration in semantic memory. More importantly, its error types and distribution show apparent discrepancy from that of alphabetic script. Presumably because Chinese writing system is logographic in nature and the pathway of comprehension concerning syllable-orthography-morphemes mapping, while alphabetic writing system follows a principle of mapping graphemes onto phonemes and letters themselves don't stand for any meaning. Key words: Semantic dementia; Dysgraphia; Semantic memory; Chinese character