[A case of MELAS associated with prosopagnosia, topographical disorientation and PLED].

We report a case of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) associated with prosopagnosia, topographical disorientation, and periodic lateralized epileptiform discharge (PLED) on electroencephalography (EEG) in a 23-year-old right-handed man. The first MELAS attack occurred on March 1, 1991, while the patient was drinking. Magnetic resonance imaging (MRI) revealed a lesion of abnormal intensity in the left occipital lobe. The second attack occurred on October 1, 1991. This time, the major symptoms were visual loss of acute onset, nausea, and vomiting. EEG examination showed transient PLED. MRI revealed a new area of abnormal intensity in the right occipital lobe, lingual gyrus, fusiform gyrus and the posterior part of the parahippocampal gyrus. During the clinical course of the patient, prosopagnosia and topographical disorientation appeared. There have been few reports of MELAS associated with prosopagnosia, topographical disorientation, and PLED. However, MELAS attacks tend to occur in the cortex of the occipital lobe. We therefore believe that these neuropsychological symptoms and PLED are likely to be associated with MELAS.