[1] Parkwood Hosp, Gait & Brain Lab, London, ON, Canada
[2] Lawson Hlth Res Inst, London, ON, Canada
[3] Univ Western Ontario, Schulich Sch Med & Dent, Div Geriatr Med, Dept Med, London, ON N6C 5J1, Canada
[4] Univ Western Ontario, Schulich Interfac Program Publ Hlth, Dept Epidemiol & Biostat, London, ON N6C 5J1, Canada