Diagnosis of MID is more difficult. Family and friends may not detect any obvious events linked to mental deterioration, but see a progressive decline in mental powers. Sometimes, on reflection, they can recall illnesses which may have been minor strokes, or identify a more abrupt change. Scans may show infarct damage in the brain. However, it is not always possible to distinguish MID from Alzheimer's during life, and because both are common diseases in old age, it is possible for people to have both conditions.
Several factors increase the risk of vascular disease.
The most significant are high blood pressure and smoking. Cigarette smoking is implicated in about a third of strokes. Brain cells which have been destroyed cannot be repaired, and so the damage done to the brain by a stroke is permanent. However, the brain can sometimes find ways to function around damaged areas, and confusion after a stroke does sometimes improve. People with vascular dementia should be offered a skilled multidisciplinary assessment of their condition through referral to a specialist.