Symptoms can vary depending on whether the stroke is caused by a blood clot (ischemic stroke) or bleeding (hemorrhagic stroke), where the stroke occurs in the brain, and how bad it is. A stroke usually happens suddenly but may occur over hours. For example, you may have mild weakness at first. Over time, you may not be able to move the arm and leg on one side of your body. If several smaller strokes occur over time, you may have a more gradual change in walking, balance, thinking, or ...