To the Editor.
—Dobkin et al1 assert that the reductions in cerebral blood flow in patients with unilateral stroke are due to cerebrovascular disease in the symptomatic hemisphere and diaschisis in the contralateral hemisphere. However, their data show that the median cerebral blood flow in the region of the infarct, in the affected hemisphere, and in the contralateral hemisphere or homologous area to the infarct was the same and that all four of these values were below the 95% confidence limit of their normal controls.The most economical hypothesis is that stroke develops in patients with a diffuse impairment of cerebral blood flow. The depression in cerebral blood flow in the "normal" hemisphere was measured an average of 21 days after stroke, which hardly fits the reversibility criterion for cerebral diaschisis. Cerebral blood flow prior to stroke has already been reported in patients with basilar insufficiency. These studies all
Stolzberg S. No Diaschisis After Stroke. Arch Neurol. 1990;47(6):621. doi:10.1001/archneur.1990.00530060025010