Evaluation of Cerebrovascular Disease

Abstract
UNILATERAL compression of the carotid artery has been used for several years as a diagnostic test, most frequently in patients with cerebrovascular disease.1,2However, evaluation of the adequacy of the compression to produce a significant occlusion of the artery is a difficulty constantly encountered, which makes it difficult to render objective judgments and to compare results. Among the various criteria employed are disappearance of pulse to digital palpation of a vessel distal to the common carotid artery, presence or absence of the carotid sinus reflex, and sensation of collapse of the vessel. However, none of these has proven to be sufficiently reliable. With the view of obviating these difficulties, Toole and Bevilacqua3proposed to record the volumetric pulses of the ear lobe with photoplethysmograms during the carotid compression test. Using this technique, a much higher degree of reliability of common carotid compression is obtained. Nevertheless, under certain