[A case of carbon monoxide poisoning by explosion of coal mine presenting as visual agnosia: re-evaluation after 40 years]

We re-evaluated a case of carbon monoxide poisoning presenting as visual agnosia who had been injured by explosion of Miike-Mikawa coal mine 40 years ago. In an early stage, his main neuropsychological symptoms were visual agnosia, severe anterograde amnesia, alexia, agraphia, constructional apraxia, left hemispatial neglect and psychic paralysis of gaze, in addition to pyramidal and extra pyramidal signs. At the time of re-evaluation after 40 years, he still showed visual agnosia associated with agraphia and constructional apraxia. Concerning visual agnosia, recognition of the real object was preserved, while recognition of object photographs and picture was impaired. Thus, this case was considered to have picture agnosia as he could not recognize the object by pictorial cues on the second dimensional space. MRI examination revealed low signal intensity lesions and cortical atrophy in the bilateral parieto-occipital lobes on T1-weighted images. Therefore, the bilateral parieto-occipital lesions are likely to be responsible for his picture agnosia.