The electroencephalogram (EEG) and lumbar puncture have lost favor in stroke diagnosis but the former is possibly underused as a readily available means of detecting cortical infarction in the wake of ischemia of a region of one hemisphere. It allows a distinction to be made between occlusion of a small and a large vessel, because focal EEG abnormalities are sparse or absent with a deep lacunar stroke. The technique finds more use in distinguishing between transient alterations in nervous function that are a result of seizures and episodes caused by focal ischemia.
Whereas most cerebral arteries can be evaluated only indirectly, more direct clinical means of physical examination are available for the evaluation of the common and internal carotid arteries in the neck. With severe atherosclerotic stenosis at the level of the carotid sinus auscultation discloses a bruit, best heard with the bell of the stethoscope held against the skin just tightly enough to create a seal (excessive pressure creates a diaphragm of the skin and filters the low-pitched frequencies that are typical of the bruit of carotid stenosis). Occasionally, a bruit at the angle of the jaw is caused by stenosis at the origin of the external carotid artery or is a radiated murmur from the aortic valve and can then be misleading. If the bruit is loudest at the angle of the jaw, the stenosis usually lies at the proximal internal carotid; if heard lower in the neck, it is in the common carotid or subclavian artery and may be radiated from the aortic valve. Rarely, stenosis in vertebral arteries or vascular malformations at the base of the brain produces bruits that are heard posteriorly in the neck.
The presence of a bruit in the neck is an indication of cerebrovascular disease but its detection is not highly correlated with the presence of severely stenotic lesions as assessed by ultrasonography or angiography. In the past, the physician was almost completely dependent on the details of the nature of the bruit but these details are now of limited interest. An additional though infrequent sign of carotid occlusion is the presence of a bruit over the opposite carotid artery, heard by placing the bell of the stethoscope over the eyeball (ocular bruit). As pointed out by Pessin and colleagues (1983), this murmur is often caused by augmented circulation through the patent vessel but there have been as many instances in our experience when a bruit over the eye instead reflects a stenosis in the intracranial portion of the carotid artery on that side. These and other tests for assessing carotid flow have been supplanted by ultrasound insonation and imaging of the carotid artery, but retinal examination remains valuable in that it may demonstrate emboli within retinal arteries, either shiny white or reddish in appearance; this is another important sign of carotid disease (crystalline cholesterol, termed Hollenhorst plaque, is sloughed from an atheromatous ulcer).
The clinical picture that results from an occlusion of any one artery differs in minor ways from one patient to another, but there is sufficient uniformity to justify the assignment of a typical syndrome to each of the major cerebral arteries. The identification of these syndromes by careful examination is one of the cardinal skills of the clinical neurologist. The following descriptions apply particularly to the clinical effects of ischemia and infarction caused by embolism and thrombosis. Although hemorrhage within a specific vascular territory may give rise to many of the same effects, the total clinical picture is different because it usually involves regions supplied by more than one artery and, by its deep extension and pressure effects, causes secondary features of headache, vomiting, and hypertension, as well as a series of falsely localizing signs, as described in Chaps. 16 and 30.