"Masters and servants" in parkinsonian gait: a three-dimensional analysis of biomechanical changes sensitive to disease progression.

Gait disorder is a very frequent and disabling symptom in Parkinson's disease (PD). The aim of this study was to identify the main kinetic and kinematic features of PD gait according to different disease stages: early (Early Group), intermediate without freezing (Non-Freezers) and intermediate with freezing (Freezers). Kinematic data showed a distal to proximal progression of impairment from the early to the intermediate with freezing stage. The Early Group showed more accentuated ankle dorsiflexion during stance than the other PD subgroups; the Freezers showed a more flexed hip position at initial contact and a reduced range of motion (ROM) during stance compared with the other patients. The individuals in the intermediate stage (with or without freezing) displayed limited knee ROM. Distal to proximal progression of lower limb impairment in PD might be an expression of a rostral to caudal degeneration of locomotor control centers. Evaluation of the relationship between gait features "Masters and servants" in parkinsonian gait: a three-dimensional analysis of biomechanical changes sensitive to disease progression and disease progression may promote the development of tailored rehabilitation programs.