Which measures of physical function and motor impairment best predict quality of life in Parkinson's disease? - Ellis T; Cavanaugh JT; Earhart GM; Ford MP; Foreman KB; Dibble LE; Ellis, T; Cavanaugh, J T; Earhart, G M; Ford, M P; Foreman, K B; Dibble, L E (Parkinsonism & Related Disorders, 2011)