The case study of a patient with alexia and agraphia who can read kana words but not kana single letters

Abstract

A 79-year-old right-handed man who is a retired accountant developed alexia specific to single kana (syllabogram) letters following a cerebral infarction in the left medial occipitotemporal region. Neurological examinations revealed right upper quadrantanopia, alexia, agraphia, and color anomia. The patient could read kana words and kanji (logogram) words correctly but not a single kana letter or kana non-words. Tracing a kana letter with his finger did not improve his reading performance. Following the auditory presentation of a syllable, the patient was unable to point to the corresponding single kana letter. He also had difficulty writing kana letters that overlapped with those he could not read. Thus, his ability to read and write single kana letters was severely impaired, whereas his ability to read kana words was preserved. These findings suggest that the patient retained intact word forms but had impaired representations of kana letters. He may be able to read kana words using word forms as a whole, even though he cannot read individual letters with confidence.