Bzdúšková Diana, Valkovič Peter, Hirjaková Zuzana, Kimijanová Jana, Hlavačka František
Institute of Normal and Pathological Physiology, Centre of Experimental Medicine Slovak Academy of Sciences, Sienkiewiczova 1, 813 71, Bratislava, Slovak Republic.
Institute of Normal and Pathological Physiology, Centre of Experimental Medicine Slovak Academy of Sciences, Sienkiewiczova 1, 813 71, Bratislava, Slovak Republic; Second Department of Neurology, Faculty of Medicine, Comenius University, Limbová 5, 833 05, Bratislava, Slovak Republic.
Gait Posture. 2018 Sep;65:169-175. doi: 10.1016/j.gaitpost.2018.07.162. Epub 2018 Jul 19.
Impairments of postural stability occur with increasing age and in neurodegenerative diseases like the Parkinson's disease (PD). While changes in balance have been described in many studies under steady-state conditions, less is known about the dynamic changes in balance following sudden transition to different sensory inputs.
The aim was to clarify different effects of age and Parkinson's disease on dynamic postural responses immediately after lower leg muscle stimulation offset. Sudden removing of active sensory input represents a transient period in balance control.
Postural responses of 13 young, 13 healthy elderly and 13 PD patients to proprioceptive bilateral vibration of soleus muscles during stance were assessed by a force platform and two accelerometers attached on the upper and the lower trunk. The experimental protocol consisted of 2 conditions of soleus muscle vibration with 1) eyes open and 2) eyes closed randomly repeated four times.
During vibration period before stimulus offset, postural responses were similar in elderly and PD patients. Contrary, immediately after vibration offset significantly larger backward amplitude of centre of foot pressure (CoP) displacement and trunk tilts were observed in PD patients compared to healthy peers. In returning to vertical position, peak-to-peak amplitudes, maximal velocity of CoP and trunk tilts significantly increased in PD patients. Without vision, their postural responses were more enhanced. The differences between young and elderly were found in most parameters in transient period after vibration offset and also during vibration.
The PD patients showed more unstable transient postural responses to selective sensory stimulation switch off, which may reflect impairment of sensory reweighting in balance control. Understanding how early stages PD patients differ in balance control from neurologically intact peers may help researchers and clinicians to refine their intervention and fall prevention programs.
姿势稳定性受损随着年龄增长以及在帕金森病（PD）等神经退行性疾病中出现。虽然在许多研究中已经描述了稳态条件下的平衡变化，但对于突然转换到不同感觉输入后平衡的动态变化了解较少。
目的是阐明年龄和帕金森病对小腿肌肉刺激停止后立即出现的动态姿势反应的不同影响。主动感觉输入的突然去除代表了平衡控制中的一个过渡时期。
通过一个测力平台和两个分别附着在上躯干和下躯干的加速度计，评估13名年轻受试者、13名健康老年人和13名帕金森病患者在站立时比目鱼肌双侧本体感觉振动的姿势反应。实验方案包括比目鱼肌振动的2种条件，1）睁眼和2）闭眼，随机重复4次。
在刺激停止前的振动期间，老年人和帕金森病患者的姿势反应相似。相反，与健康同龄人相比，在振动停止后立即观察到帕金森病患者的足底压力中心（CoP）位移和躯干倾斜的向后幅度明显更大。在恢复到垂直位置时，帕金森病患者的峰峰值幅度、CoP和躯干倾斜的最大速度显著增加。在没有视觉的情况下，他们的姿势反应增强得更多。在振动停止后的过渡时期以及振动期间，年轻和老年人在大多数参数上存在差异。
帕金森病患者对选择性感觉刺激关闭表现出更不稳定的短暂姿势反应，这可能反映了平衡控制中感觉重新加权的损害。了解早期帕金森病患者在平衡控制方面与神经功能正常的同龄人有何不同，可能有助于研究人员和临床医生完善他们的干预和跌倒预防计划。
