Are you referring to the title of the book by Jill Bolte Taylor? If so, the title is a play on words and the word "stroke", in addition to having the meaning Su.Ki. described, refers to a medical condition where blood flow to the brain is interrupted and the result can be paralysis and problems with speech. Her book and TED Talk about this explain how her stroke gave her incredible insight as to how the brain functions and can heal itself.

'Insight' is an intuitive understanding, an ability to perceive the true and inner nature of something. 'A stroke of insight' is when this suddenly happens. A similar expression is 'a flash of insight'.