Parieto-cerebellar loop impairment in ataxic hemiparesis: proposed pathophysiology based on an analysis of cerebral blood flow.
Sixteen stroke patients suffering from ataxic hemiparesis syndrome were studied with regional cerebral blood flow measured by 133-Xenon inhalation technique (12 patients) and by SPECT (HMPAO) (9 patients). The causative lesions (hematoma in 7 and infarct in 9), unilateral in 15 patients and bilateral in 1, were located in the posterior two-thirds of the corona radiata, thalamo-capsular and subthalamus regions, or cerebral peduncle. Ataxia of the cerebellar type was unilateral in 15 patients and bilateral in 1 with similar, deep, bilateral causative lesions. Four patients presented some characteristics of proprioceptive ataxia (mixed ataxia). Associated cognitive disturbances were present in 9 patients and absent in 7. Eleven of the 12 subjects studied by 133-Xenon inhalation technique showed limited centro-parietal hypoperfusion, mainly in the inferior parietal lobule, ipsilateral to the causative lesion and bilaterally in the patient with bilateral lesions and ataxia. Ipsilateral hypoperfusion was confirmed in 7/9 patients studied by SPECT, which also demonstrated contralateral cerebellar hypoperfusion in 4 patients. These findings suggest that ataxic hemiparesis syndrome results from functional depression (diaschisis) consequent to the interruption at many levels of an "inferior parietal associative cortex-cerebellar anterior lobe" circuit.
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Department of Neurology, Hôtel-Dieu Hospital, Montreal, Quebec, Canada.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002524:Cerebellar Ataxia / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D002531:Cerebellum / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology*; D002544:Cerebral Infarction / Q000473:pathology / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002561:Cerebrovascular Disorders / Q000473:pathology / Q000503:physiopathology; D003072:Cognition Disorders / Q000150:complications; D005260:Female; D006406:Hematoma / Q000473:pathology / Q000503:physiopathology; D006429:Hemiplegia / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010296:Parietal Lobe / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology*; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D014980:Xenon Radioisotopes
D014980:Xenon Radioisotopes