A transient ischemic attack is a transient episode of neurologic dysfunction caused by ischemia – either focal brain, spinal cord, or retinal – without acute infarction. TIAs have the same underlying cause as strokes: a disruption of cerebral blood flow. Symptoms caused by a TIA resolve in 24 hours or less. TIAs cause the same symptoms associated with stroke, such as contralateral paralysis or sudden weakness or numbness. A TIA may cause sudden dimming or loss of vision (amaurosis fugax), aphasia, dysarthria and mental confusion. But unlike a stroke, the symptoms of a TIA can resolve within a few minutes or within 24 hours. Having a TIA is a risk factor for eventually having a stroke or a silent stroke.