11/12. Cerebral blood flow and oxygen metabolism before and after a stroke-like episode in patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS).Cerebral blood flow and oxygen metabolism were examined in two patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) using positron emission tomography (PET). Regional cerebral blood flow (rCBF), regional cerebral oxygen metabolic rate (rCMRO2) and regional oxygen extraction fraction (rOEF) were determined with the steady-state technique using oxygen-15-labeled tracers (15O2, C15O2 and C15O). Case 1, a 45-year-old woman, presented with abrupt onset of fluent aphasia. T2-weighted magnetic resonance imaging (MRI) showed a high signal intensity lesion in the left temporoparietal region. The first PET study on day 16 showed increased rCBF and decreased rCMRO2 in the temporal region. In the second PET study, on day 35, rCBF in the temporal region had decreased. Case 2 was a 19-year-old male; the second son of Case 1. He complained of transient blurring of vision, and then generalized tonic-clonic convulsion occurred. A PET study six days before this stroke-like episode demonstrated increased rCBF in both frontal lobes and putamen, where MRI showed lesions after the episode. Focal hyperemia of the lesion antedated and lasted for at least sixteen days after the stroke-like episode in these MELAS patients. These stroke-like episodes appear to be the result of metabolic dysfunction in neural tissue, although the role of an ischemic vascular event cannot be ruled out.- - - - - - - - - - ranking = 1keywords = putamen (Clic here for more details about this article) |
12/12. Subcortical crossed aphasia.A 55 year-old, right-handed, hypertensive woman with global aphasia, due to a spontaneous hemorrhage in the right putamen extending to the periventricular white matter was examined thirteen days after the acute onset of stroke. She had left hemiplegia and inability to speak. She displayed no spontaneous speech output and was capable only of occasional undifferentiated grunts in conversation. Other language modalities such as auditory and reading comprehension, naming, repetition and writing were severely impaired. Her aphasia was classified as global aphasia. Forty-five days after the onset of stroke, rapid recovery from the aphasia with mild deficits in speaking, naming, and repetition was detected. This case is a good example of crossed aphasia, favouring the importance of deep structures of the right hemisphere in this type of aphasia. Rapid recovery is an important feature.- - - - - - - - - - ranking = 1keywords = putamen (Clic here for more details about this article) |
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