Strategies of segmental stabilization during gait in Parkinson's disease

This study compared the postural strategies adopted by patients with Parkin son's disease (PD; n=16) during locomotion to those of elderly controls (n= 16). We focused mainly on the head and trunk stabilization modes in sagitta l and frontal planes. Subjects were asked to walk at their natural speed on an uniformly gray, flat ground. Gait data were recorded before and 1 h aft er L-dopa intake and were analyzed by an automatic motion analyser (Elite s ystem). The modes of segmental stabilization adopted by each group were det ermined by means of the anchoring index, associated with cross-correlation functions between angular movements of pairs of segments. The major finding s were: (a) PD patients generally had shorter step length, greater step wid th, and slower gait velocity than the healthy elderly. (b) No difference in angular dispersion of any anatomical segment studied was observed between the two groups. (c) PD patients had adopted a strategy of head stabilizatio n on the shoulder ("en bloc" functioning of the head-shoulder unit) about t he roll axis only. (d) PD patients displayed head and shoulder angular move ments around the roll axis that were more correlated than those of controls , confirming their more en bloc functioning. (e) Shoulder and hip were equa lly stabilized in space in the two groups around the roll axis. (f) There w as no difference between the two groups about the pitch axis where an en bl oc functioning of the whole trunk was shown. These results are discussed wi th respect to the similarities observed between the visuo-locomotor PD perf ormances and those of children.