Question: What is (are) Cerebral Arteriosclerosis ?
Answer: Cerebral arteriosclerosis is the result of thickening and hardening of the walls of the arteries in the brain. Symptoms of cerebral arteriosclerosis include headache, facial pain, and impaired vision. Cerebral arteriosclerosis can cause serious health problems. If the walls of an artery are too thick, or a blood clot becomes caught in the narrow passage, blood flow to the brain can become blocked and cause an ischemic stroke. When the thickening and hardening is uneven, arterial walls can develop bulges (called aneurysms). If a bulge ruptures, bleeding in the brain can cause a hemorrhagic stroke. Both types of stroke can be fatal. Cerebral arteriosclerosis is also related to a condition known as vascular dementia, in which small, symptom-free strokes cause cumulative damage and death to neurons (nerve cells) in the brain. Personality changes in the elderly, such as apathy, weeping, transient befuddlement, or irritability, might indicate that cerebral arteriosclerosis is present in the brain. Computer tomography (CT) and magnetic resonance imaging (MRI) of the brain can help reveal the presence of cerebral arteriosclerosis before ischemic strokes, hemorrhagic strokes, or vascular dementia develop.
Source: NINDS

Question: what research (or clinical trials) is being done for Cerebral Arteriosclerosis ?
Answer: The NINDS supports an extensive research program on stroke and conditions that can lead to stroke. Much of this research is aimed at finding ways to prevent and treat conditions such as cerebral arteriosclerosis.
Source: NINDS