CROSSED CEREBELLAR DIASCHISIS AND BRAIN RECOVERY AFTER STROKE

Background and Purpose Although crossed cerebellar diaschisis is well recognized after stroke, there is controversy concerning its clinical correlations and serial changes, and little is known about its prognos tic value. Methods We studied crossed cerebellar diaschisis and cerebr al hypoperfusion in 47 patients with acute middle cerebral cortical in farction using Tc-99m-hexamethylpropyleneamine oxime and single-photon emission computed tomography within 72 hours of stroke onset. Thirty- one of these patients had outcome studies at 3 months; 15 of the 31 un derwent an additional scan after acetazolamide injection. Tissue loss was determined with computed tomography, performed at outcome in 28 pa tients. Clinical stroke severity was assessed with the Canadian Neurol ogical Scale and Barthel Index. Cerebellar blood flow asymmetry was st udied in 22 healthy, age-matched control subjects. Results Cerebellar blood flow asymmetry was significant in patients (mean+/-SE, 9.76+/-0. 78%; P<.001) but not in control subjects (-0.22+/-0.56%). Crossed cere bellar diaschisis was strongly associated with infarct hypoperfusion v olume at both acute (regression coefficient+/-SE(b), b=6.76+/-0.65; P< .001) and outcome stages (b=6.13+/-0.63; P<.001). Cross-sectionally ov er the first 72 hours, infarct hypoperfusion volume decreased by 2% fo r each hour from onset (P<.05), while crossed cerebellar diaschisis re mained unchanged. Canadian Neurological Scale score at the acute stage was negatively associated with acute crossed cerebellar diaschisis (b =-0.10+/-0.05; P<.05) after allowing for infarct hypoperfusion volume. Crossed cerebellar diaschisis did not change between acute-stage, out come, and postacetazolamide scans. Acute-stage crossed cerebellar dias chisis predicted outcome Barthel Index score (b=-0.28+/-0.13; P=.05) a nd tissue loss (b=3.81+/-0.96; P<.001) but was no longer an independen t prognostic factor after allowing for acute-stage infarct hypoperfusi on volume. Conclusions This study shows that crossed cerebellar diasch isis is a functional phenomenon that correlates with both stroke sever ity and infarct hypoperfusion volume and persists despite neurological recovery. Although acute-stage crossed cerebellar diaschisis has no p rognostic value independent of acute-stage hypoperfusion volume, it mi ght indicate the proportion of nutritional to nonnutritional perfusion at the infarct site and hence be useful in the evaluation of reperfus ion therapies in the acute stage.