My father has had tingling in his left arm and leg (entire left side of body) all day. He's had a heart attack about 8 years ago and suffers from diabetes, high blood pressure and a host of other ailments. He has not had any pain, slurred speech or other symptoms associated with this today and has no health insurance (so he's always hesitant to go into the ER if unnecessary) - should we be worried? What should we watch for?