Clinicopathological observations in middle cerebral artery occlusion in the cat.

This study was designed to investigate the relationships among neurological deficits, changes in the electroencephalogram (EEG) and morphological damage over a one week period following temporary occlusion (2 h) of the middle cerebral artery (MCA) in the cat. The animals were grouped into mild, moderate, and severe stroke based on the EEG alterations produced 30 min after the MCA occlusion. All three grades of stroke showed a precipitous fall in mean EEG amplitude followed by a recovery during a 4 h recirculation period. Over the subsequent 7 days there was a gradual secondary depression in the EEG amplitude. Post-operatively, a secondary fall in EEG amplitude in the contralateral hemisphere was also noted in all stroke groups corresponding to the clinical phenomenon of 'diaschisis'. The overall neurological score differed significantly among the severe, moderate, and mild stroke groups. The neurological deficits on the 7th day were highly correlated with the degree of morphological damage. Additionally, the reduction of EEG was also well correlated with the pathological data. This stroke model in the cat has provided important data concerning the restitution of brain function following chronic focal ischaemia.