Burleigh-Jacobs A, Horak F B, Nutt J G, Obeso J A
Department of Physiology, Oregon Health Sciences University, Portland, USA.
Mov Disord. 1997 Mar;12(2):206-15. doi: 10.1002/mds.870120211.
We studied anticipatory postural adjustments contributing to gait initiation deficits in patients with Parkinson's disease (PD) to determine if these deficits could be improved by administration of levodopa or by external stimuli. Ground reaction forces and body kinematics were recorded for self-generated and cutaneous cue-triggered step initiation in normal subjects and in PD subjects when OFF and when ON. The effects of assisting anticipatory postural sway with a surface translation coupled with a cutaneous cue were also examined. Decreased force production, decreased velocity of movement, and slowed execution of the anticipatory postural adjustments for self-generated step characterized step initiation in PD subjects when OFF. These impairments were significantly less evident when the PD subjects were ON. Both PD and normal subjects increased force and velocity of movement when a cutaneous cue was used as a go signal. When subjects voluntarily initiated a step in response to the surface translation, both PD and normal subjects executed the anticipatory postural adjustments for step more rapidly, but the PD subjects, both ON and OFF, failed to increase force to execute push-off more rapidly. In conclusion, dopaminergic therapy and an external stimulus similarly improve the deficient force production for the anticipatory postural adjustments associated with step initiation in PD. The findings also suggest that force production during the postural adjustment phase of self-generated, but not externally triggered, step initiation is influenced by dopaminergic pathways.
我们研究了帕金森病（PD）患者中导致步态起始缺陷的预期姿势调整，以确定左旋多巴给药或外部刺激是否能改善这些缺陷。记录了正常受试者以及PD受试者在未服药（OFF）和服药（ON）状态下，自发和皮肤线索触发的步起始过程中的地面反作用力和身体运动学数据。还研究了表面平移结合皮肤线索辅助预期姿势摆动的效果。未服药时，PD受试者自发步起始的特征是力量产生减少、运动速度降低以及预期姿势调整的执行减慢。服药时，这些损伤明显减轻。当使用皮肤线索作为开始信号时，PD受试者和正常受试者都会增加运动的力量和速度。当受试者响应表面平移自愿起始一步时，PD受试者和正常受试者都会更快地执行预期的步姿势调整，但无论服药与否，PD受试者都未能增加力量以更快地执行蹬离动作。总之，多巴胺能治疗和外部刺激同样能改善PD患者中与步起始相关的预期姿势调整的力量产生不足。研究结果还表明，自发而非外部触发步起始的姿势调整阶段的力量产生受多巴胺能通路影响。
