British researchers say about 50 percent of the people who suffer a major stroke after having a mini-stroke do so within 24 hours of the minor stroke event. Researchers say the message that can be taken away from their study is that people who have these mini-strokes--called transient ischemic attacks--should seek medical attention immediately. Scientists say this is especially true if the person is suffering from weakness or has problems with their speech that lasts more than 10 minutes.