Is Transcranial Magnetic Stimulation a Useful Clinical Adjunct for Predicting Stroke Occurrence and Severity following Transient Ischemic Attack? A Prospective Cohort Study

Stroke continues to be one of the leading causes of death, long-term adult disability, and illness in Canada. Approximately 1/4 of ischemic strokes are preceded by a brief episode of neurological deficit, or transient ischemic attack (TIA). During a TIA, individuals experience stroke-like symptoms that rapidly disappear. Early stroke risk in patients with TIA is considerable and North American population-based estimates of recurrent stroke range from 9.5% at 90 days, to 14.5% at 1 year. These data highlight the importance of intervention for secondary stroke prevention. However, efforts to estimate stroke risk using clinical profile and diagnostic imaging have shown variable predictive value and validity. Therefore, new markers are needed to help clearly identify high risk individuals and improve current stroke prevention strategies. Jodi Edwards is studying if cortical motor excitability, measured using a brain stimulation technique called Transcranial Magnetic Stimulation (TMS), is a marker of increased stroke risk in individuals with TIA. TMS provides information about the activity of different types of neurons in the brain and with this research, she will determine if there is an association between altered thresholds of intracortical inhibition in the cortical hemisphere affected by TIA and stroke occurrence. In addition, she is also investigating if larger asymmetries in intracortical thresholds are predictive of increased clinical severity in stroke subsequent to TIA. This research has the potential to significantly advance the understanding of the mechanisms underlying TIA and provide a new technique for the identification of high-risk patients following a TIA. Ultimately, this study has the potential to improve stroke prevention strategies and reduce recurrent stroke risk in patients with TIA.