William F. House Lecture. Neurotologic manifestations of microvascular hypoperfusion.

Some forms of dizziness, imbalance, and hearing change have been suspected to result from a vertebral basilar artery circulatory deficit. Microvascular hypoperfusion of the central nervous system (CNS) is proposed as a more likely mechanism than thromboembolic phenomena of the parent arteries. Symptoms of end-organ pathology must be differentiated from CNS causes to assure implementation of an appropriate treatment strategy. Guidelines for the evaluation of these patients are provided. Changes in platelet and red and white blood cell morphology are proposed as more significantly influencing blood flow than blood pressure or vessel caliber. Medications that alter blood rheology, have been found to alleviate the acute symptoms of microvascular hypoperfusion. Residual balance deficits from presumed long-term CNS ischemia have then been relieved by balance rehabilitation training. With the recognition of this disease entity there appears another means of aiding patients with dizziness and balance problems who have previously experienced long-term disability. The results of a preliminary study of 378 patients merits further investigation of the proposed pathophysiology and treatment measures.