[A case of crossed aphasia in a dextral patient with polycythemia].

We report a 72-year-old right-handed man who was diagnosed as having crossed aphasia. He had polycythemia, hypertension and an old cerebral infarction in the right occipital lobe. He was admitted to our hospital because of muscle weakness in the left extremities at the age of 71. In the laboratory data, red blood cells(689 x 10(4)/microliter) and platelets(87.6 x 10(4)/microliter) were increased in number. Brain CT detected a right putaminal hematoma and an old infarct in the occipital lobe on the right. After admission, he developed non-fluent speech, and impairments of auditory comprehension, writing and naming due to the infarction in his right cerebral hemisphere including the middle cerebral artery distribution. The standard language test of aphasia(SLTA) revealed marked impairments in the language function, except for reading kana and kanji words. This writing was severely impaired compared with other language dysfunctions. Auditory comprehension, repetition and reading were impaired at the sentence level rather than at the kana word level. Furthermore, he suffered from left hemiparesis and left unilateral spatial neglect. We diagnosed his impairments of language function as crossed aphasia based on his right-handedness, CT findings and the results of SLTA. His language center was considered to be located in both cerebral hemispheres. Compared with typical findings in reported cases of crossed aphasia, the presence of both non-fluent speech and mutism were consistent with previous observations. However, the marked impairments of auditory comprehension, repetition and naming were different. Polycythemia and hypertension were considered to be the risk factors of cerebral infarction in our patient.