[1] Dalhousie Univ, Div Geriatr Med, Halifax, NS, Canada
[2] Dalhousie Univ, Div Neurol, Halifax, NS, Canada
[3] Univ Toronto, Sunnybrook & Womens Coll, Hlth Sci Ctr, Toronto, ON, Canada
[4] Univ Toronto, Dept Med, Div Neurol, Toronto, ON, Canada
[5] Pfizer Canada Inc, Div Med, Montreal, PQ, Canada