FOR THIS SYMPOSIUM we have reviewed a personal series of cerebrovascular cases, chiefly thrombotic or embolic, and determined the frequency and type of dizziness associated with occlusion of each of the cerebral arteries—internal carotid, middle cerebral, basilar, etc. Before presenting the analysis, a few general remarks about the subject are in order, since the viewpoint of the observer colors his observations and conclusions. In this discussion the term dizziness will be used. Vertigo, in English, has the connotation of rotation and many patients with a vestibular disorder, peripheral or central, do not have or describe a spinning feeling. The term dizziness is used, therfore, to embrace all vestibular symptomatology, whether or not it is rotational. When "turning" is present, we may speak of rotational dizziness or vertigo. It is extremely common to hear, "It can't be vestibular, there was no turning," a viewpoint with which we disagree. Dizziness is a