Stroke is a condition in which there is a loss of blood flow to the brain or regional blockage of blood flow. Patients may develop almost identical symptoms in both cases. However, the severity of the patient's condition depends on the area of the brain where the blood flow was disrupted , how much area was damaged , and how quickly the incident occurred . Common symptoms include dizziness , difficulty walking, difficulty balancing , difficulty speaking , weakness , numbness on one side of the body , blurred vision , darkening or sudden double vision