Most commonly, a bruit is assessed during examination by the healthcare professional. Carotid bruits are best heard with the bell of the stethoscope over the anterior border of the scalene muscle midway between the clavicle and mastoid process. The intensity of the bruit is not an accurate predictor of the degree of stenosis. Bruits occur in 2 to 5% of the elderly population and are known to increase stroke risk. Approximately 25% of those with a carotid bruit will have a significant stenosis. A Hollenhorst plaque, usually found by ophthalmology, is an embolus from the carotid or innominate artery that causes occlusion of a retinal or branch artery. If symptomatic, it may cause amaurosis fugax (or transient monocular blindness). This occurs on the ipsilateral side as the stenosis. Nonreversible visual loss may also ocur.