Grant: Operating Grant

Approximately 25% of strokes are preceded by a mini-stroke, or transient ischemic attack (TIA). A TIA occurs when people experience stroke-like symptoms that rapidly disappear and the risk of future stroke after a TIA is very high. However, TIA is very difficult to accurately diagnose, since the symptoms of TIA disappear so rapidly and there are several conditions that have similar symptoms, but are not TIA (e.g., TIA-mimic). Information from magnetic resonance imaging (MRI) can be used to help identify TIA, but only a percentage of people with TIA have abnormal MRIs. A brain stimulation technology, called Transcranial Magnetic Stimulation (TMS), provides information about the activity of different types of cells in the brain. Disruptions in brain activity have been shown to occur shortly after TIA, but it is not known whether these disruptions are related to abnormal MRIs after TIA, if these disruptions are permanent, or if they differ in people with TIA compared to people with TIA-mimic. The purposes of this study are 1) to test if disruptions in brain activity are related to abnormal MRIs after a TIA, 2) to test how long brain activity remains changed after a TIA, and 3) to test if these changes can help distinguish TIA from a TIA-mimic. We will use both TMS and MRI in individuals with TIA and TIA-mimic. Participants will complete the first session of TMS and an MRI within two weeks of their symptoms and several follow-up sessions within the following two months. This will allow us to test how long changes in brain activity last after a TIA. The results of this study will provide information about new ways to identify people at high risk of stroke and have the potential to improve stroke prevention strategies after TIA.