Grassi Lucia, Rossi Stefano, Studer Valeria, Vasco Gessica, Motta Caterina, Patanè Fabrizio, Castelli Enrico, Rossi Silvia, Cappa Paolo
Department of Mechanical and Aerospace Engineering, "Sapienza" University of Rome, Rome, Italy.
Department of Economics and Management, Industrial Engineering, University of Tuscia, Viterbo, Italy.
J Neuroeng Rehabil. 2017 Jan 10;14(1):4. doi: 10.1186/s12984-016-0216-8.
Multiple Sclerosis (MS) is a widespread progressive neurologic disease with consequent impairments in daily activities. Disorders of balance are frequent and equilibrium tests are potentially useful to quantify disability and to verify treatment effectiveness. The fair sensitivity of the widely used not-perturbed tests to detect balance disturbances in MS patients have prompted the development of mechatronic systems capable to impose known equilibrium perturbations, in order to challenge the balance control and, consequently, to better assess the level of impairment. We sought to clarify whether the proposed perturbed-test is capable to discriminate healthy subjects from patients with MS, even in mild or in the absence of clinically evident balance disturbances.
We assessed balance performances of 17 adults with MS and 13 age-matched healthy controls (HC) using both perturbed (PT) and not-perturbed (NPT) postural tests by means of a 3 Degree Of Freedom (DOF) rotational mechatronic platform. Participants stood barefoot on the platform in standing position and their center of pressure (CoP) was gathered by using a pressure matrix. Each trial lasted 30 s and was carried out with and without visual stimuli. Several postural indices were computed for each trial. Correlations between postural indices and clinical scales were analyzed.
No significant differences were found between groups for all indices when subjects performed NPTs. Conversely, significant differences in postural indices between MS and HC emerged during PTs. Additionally, PTs revealed significant differences between patients without any cerebellar impairment (cerebellar EDSS subscore equal to 0) and HC. The discrimination capability of PTs was confirmed by the ROC analysis. No significant change of the selected metrics occurred in HC when NPTs were performed with eyes closed, while indices presented a significant worsening in MS subjects.
Not-perturbed tests showed lower sensitivity than perturbed ones in the identification of equilibrium impairments in minimally disabled MS patients. However, not-perturbed tests allow to better evaluate the influence of visual flow disturbances on balance control in MS. In conclusion, our findings proved that the use of the novel tests based on a 3DOF mechatronic device represents an effective tool to investigate early balance disturbances in MS.
多发性硬化症（MS）是一种广泛存在的进行性神经疾病，会导致日常活动受损。平衡障碍很常见，平衡测试对于量化残疾程度和验证治疗效果可能有用。广泛使用的非干扰性测试在检测MS患者平衡障碍方面的敏感性一般，这促使了能够施加已知平衡扰动的机电系统的开发，以便挑战平衡控制，从而更好地评估损伤程度。我们试图阐明所提出的干扰性测试是否能够区分健康受试者和MS患者，即使在轻度或无临床明显平衡障碍的情况下。
我们使用一个三自由度（DOF）旋转机电平台，通过干扰性（PT）和非干扰性（NPT）姿势测试，评估了17名成年MS患者和13名年龄匹配的健康对照（HC）的平衡表现。参与者赤脚站在平台上的站立位置，使用压力矩阵收集他们的压力中心（CoP）。每个试验持续30秒，在有和没有视觉刺激的情况下进行。为每个试验计算了几个姿势指标。分析了姿势指标与临床量表之间的相关性。
当受试者进行NPT时，所有指标在两组之间均未发现显著差异。相反，在PT期间，MS组和HC组之间的姿势指标出现了显著差异。此外，PT显示无任何小脑损伤（小脑扩展残疾状态量表亚评分等于0）的患者与HC之间存在显著差异。ROC分析证实了PT的辨别能力。当HC闭眼进行NPT时，所选指标没有显著变化，而MS受试者的指标则显著恶化。
在识别轻度残疾MS患者的平衡损伤方面，非干扰性测试的敏感性低于干扰性测试。然而，非干扰性测试可以更好地评估视觉流干扰对MS患者平衡控制的影响。总之，我们的研究结果证明，使用基于三自由度机电装置的新型测试是研究MS早期平衡障碍的有效工具。
