By definition, a stroke occurs as the result of a blood clot in an artery or as the result of a burst blood vessel. Either way, the result leads to an interruption in blood flow to an area of the brain. When this happens, brain cells in that brain region suffer from lack of oxygen and begin to die. As brain damage begins to occur, the abilities associated with that area of the brain become lost. The abilities lost during stroke typically include speech, movement and memory. The extent of impairment experienced by a stroke patient depends on where in the brain the stroke occurred and how much of the brain was damaged.