Article

Postural instability appears to be a dopamine resistance motor deficit in persons
with Parkinson disease (PD); however, little is known about the effects of
dopamine replacement on the relative biomechanical contributions of individual
lower extremity joints during postural control tasks. To gain insight, we
examined persons with PD using both clinical and laboratory measures. For a
clinical measure of motor severity we utilized the Unified Parkinson Disease
Rating Scale motor subsection during both OFF and ON medication conditions. For
the laboratory measure we utilized data gathered during a rapid lower extremity
force production task. Kinematic and kinetic variables at the hip, knee, and
ankle were gathered during a counter movement jump during both OFF and ON
medication conditions. Sixteen persons with PD with a median Hoehn and Yahr
severity of 2.5 completed the study. Medication resulted in significant
improvements of angular displacement for the hip, knee, and ankle. Furthermore,
significant improvements were revealed only at the hip for peak net moments and
average angular velocity compared to the OFF medication condition. These results
suggest that dopamine replacement medication result in decreased clinical motor
disease severity and have a greater influence on kinetics and kinematics
proximally. This proximally focused improvement may be due to active recruitment
of muscle force and reductions in passive restraint during lower extremity rapid
force production.
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Langue : ANGLAIS