TY - JOUR
T1 - Step initiation in Parkinson's disease
T2 - Influence of initial stance conditions
AU - Rocchi, Laura
AU - Chiari, Lorenzo
AU - Mancini, Martina
AU - Carlson-Kuhta, Patricia
AU - Gross, Anne
AU - Horak, Fay B.
N1 - Funding Information:
We thank Triana Nagel-Nelson for assistance with data collection. Supported by NIH grant AG019706
PY - 2006/10/2
Y1 - 2006/10/2
N2 - In this study, we investigated how the size of preparatory postural adjustments prior to step initiation, and step length and velocity depend on initial stance width in patients with Parkinson's disease (PD) both in the ON and OFF levodopa states and in healthy elderly subjects. Twenty-one subjects with idiopathic PD and 24 age-matched healthy control subjects took two steps starting with feet on a two-plate force-platform, from either narrow or wide stance width. We measured how the magnitude of anticipatory postural adjustments (APA) and step characteristics scaled with stance width. Results showed that preparation for step initiation from wide stance was associated with a larger lateral and backward center of pressure (CoP) displacement than from narrow stance. Velocity and length of the first step were also sensitive to initial stance conditions, probably in relation with the differences in the corresponding APA. On the contrary, the duration of APA was not significantly affected by initial stance width, but it was longer in PD compared to healthy subjects, and speeded up by levodopa. Although subjects with PD did scale up the size of their APA with stance width, they had much more difficulty initiating a step from a wide stance than from a narrow stance, as shown by the greater differences from control subjects in the magnitude of the APA. Our results support the hypothesis that PD subjects maintain a narrow stance as a compensation for their inability to sufficiently increase the size of their lateral APA to allow fast step initiation in wide stance.
AB - In this study, we investigated how the size of preparatory postural adjustments prior to step initiation, and step length and velocity depend on initial stance width in patients with Parkinson's disease (PD) both in the ON and OFF levodopa states and in healthy elderly subjects. Twenty-one subjects with idiopathic PD and 24 age-matched healthy control subjects took two steps starting with feet on a two-plate force-platform, from either narrow or wide stance width. We measured how the magnitude of anticipatory postural adjustments (APA) and step characteristics scaled with stance width. Results showed that preparation for step initiation from wide stance was associated with a larger lateral and backward center of pressure (CoP) displacement than from narrow stance. Velocity and length of the first step were also sensitive to initial stance conditions, probably in relation with the differences in the corresponding APA. On the contrary, the duration of APA was not significantly affected by initial stance width, but it was longer in PD compared to healthy subjects, and speeded up by levodopa. Although subjects with PD did scale up the size of their APA with stance width, they had much more difficulty initiating a step from a wide stance than from a narrow stance, as shown by the greater differences from control subjects in the magnitude of the APA. Our results support the hypothesis that PD subjects maintain a narrow stance as a compensation for their inability to sufficiently increase the size of their lateral APA to allow fast step initiation in wide stance.
KW - Adaptation
KW - Basal ganglia
KW - Parkinson's disease
KW - Scaling
KW - Step initiation
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U2 - 10.1016/j.neulet.2006.07.027
DO - 10.1016/j.neulet.2006.07.027
M3 - Article
C2 - 16901637
AN - SCOPUS:33747779654
SN - 0304-3940
VL - 406
SP - 128
EP - 132
JO - Neuroscience Letters
JF - Neuroscience Letters
IS - 1-2
ER -