Sarabadani Tafreshi Amirehsan, Riener Robert, Klamroth-Marganska Verena
Sensory-Motor Systems Lab, Department of Health Sciences and Technology, Institute of Robotics and Intelligent Systems, ETH ZurichZurich, Switzerland.
Reharobotics Group, Medical Faculty, Spinal Cord Injury Center, Balgrist University Hospital, University of ZurichZurich, Switzerland.
Front Physiol. 2017 Jun 2;8:327. doi: 10.3389/fphys.2017.00327. eCollection 2017.
Robot-assisted tilt table therapy was proposed for early rehabilitation and mobilization of patients after diseases such as stroke. A robot-assisted tilt table with integrated passive robotic leg exercise (PE) mechanism has the potential to prevent orthostatic hypotension usually provoked by verticalization. In a previous study with rather young healthy subjects [average age: 25.1 ± 2.6 years (standard deviation)], we found that PE effect on the cardiovascular system depends on the verticalization angle of the robot-assisted tilt table. In the current study, we investigated in an older population of neurological patients (a) whether they show the same PE effects as younger healthy population on the cardiovascular system at different tilt angles, (b) whether changing the PE frequency (i.e., stepping speed) influences the PE effect on the cardiovascular system, (c) whether PE could prevent orthostatic hypotension, and finally, (d) whether PE effect is consistent from day to day. Heart rate (HR), and systolic and diastolic blood pressures (sBP, dBP) in response to PE at two different tilt angles (α = 20°, 60°) with three different PE frequencies (i.e., 0, 24, and 48 steps per minute) of 10 neurological patients [average age: 68.4 ± 13.5 years (standard deviation)] were measured on 2 consecutive days. Linear mixed models were used to develop statistical models and analyze the repeated measurements. The models show that: PE significantly increased sBP and dBP but had no significant effect on HR. (a) Similar to healthy subjects the effect of PE on sBP was dependent on the tilt angle with higher tilt angles resulting in a higher increase. Head-up tilting alone significantly increased HR and dBP but resulted in a non-significant drop in sBP. PE, in general, had a more additive effect on increasing BP. (b) The effect of PE was not influenced by its speed. (c) Neither during head-up tilt alone nor in combination with PE did participants experience orthostatic hypotension. (d) The measurement day was not a statistically significant factor regarding the effects of verticalization and PE on the cardiovascular response. We provide evidence that PE can increase steady-state values of sBP and dBP in neurological patients during head-up tilt. Similar to healthy subjects the effect on sBP depends on the verticalization angle of the robot-assisted tilt table. PE might have the potential to prevent orthostatic hypotension, but as the amount of drop in BP in response to head-up tilting was not leading to orthostatic hypotension in our patients, we could neither conclude nor reject such a preventive compensatory effect. Furthermore, we found that changing the PE speed does not influence the steady-state cardiovascular response.
机器人辅助倾斜台疗法被提议用于中风等疾病后患者的早期康复和活动。一种集成了被动机器人腿部运动（PE）机制的机器人辅助倾斜台有潜力预防通常由垂直化引发的体位性低血压。在之前一项针对相当年轻的健康受试者的研究中[平均年龄：25.1±2.6岁（标准差）]，我们发现PE对心血管系统的影响取决于机器人辅助倾斜台的垂直化角度。在当前研究中，我们在年龄较大的神经科患者群体中调查了：（a）他们在不同倾斜角度下对心血管系统的PE效应是否与年轻健康人群相同；（b）改变PE频率（即踏步速度）是否会影响PE对心血管系统的效应；（c）PE是否能预防体位性低血压；最后，（d）PE效应在不同日期是否一致。在连续两天测量了10名神经科患者[平均年龄：68.4±13.5岁（标准差）]在两种不同倾斜角度（α = 20°，60°）下，三种不同PE频率（即每分钟0、24和48步）时对PE的心率（HR）、收缩压和舒张压（sBP、dBP）。使用线性混合模型建立统计模型并分析重复测量数据。模型显示：PE显著升高了sBP和dBP，但对HR无显著影响。（a）与健康受试者类似，PE对sBP的影响取决于倾斜角度，倾斜角度越高，升高幅度越大。仅抬头倾斜显著增加了HR和dBP，但导致sBP无显著下降。总体而言，PE对升高血压有更强的累加效应。（b）PE的效应不受其速度影响。（c）无论是单独抬头倾斜还是与PE联合，参与者均未出现体位性低血压。（d）测量日期对于垂直化和PE对心血管反应的影响不是一个具有统计学意义的因素。我们提供的证据表明，在抬头倾斜期间，PE可增加神经科患者sBP和dBP的稳态值。与健康受试者类似，对sBP的影响取决于机器人辅助倾斜台的垂直化角度。PE可能有预防体位性低血压的潜力，但由于在我们的患者中，抬头倾斜引起的血压下降幅度未导致体位性低血压，我们既不能得出结论也不能排除这种预防性代偿效应。此外，我们发现改变PE速度不会影响稳态心血管反应。
