Biomedical Technology Department, Found, Don C, Gnocchi Onlus, IRCCS, Via Capecelatro 66, 20148 Milan, Italy.
J Neuroeng Rehabil. 2014 Apr 18;11:67. doi: 10.1186/1743-0003-11-67.
Arm impairment in Multiple Sclerosis (MS) is commonly assessed with clinical scales, such as Action Research Arm Test (ARAT) which evaluates the ability to handle and transport smaller and larger objects. ARAT provides a complete upper limb assessment, as it considers both proximal arm and hand, but suffers from subjectivity and poor sensitivity to mild impairment. In this study an instrumented ARAT is proposed to overcome these limitations and supplement the assessment of arm function in MS.
ARAT was executed by 12 healthy volunteers and 21 MS subjects wearing a single inertial sensor on the wrist. Accelerometers and gyroscopes signals were used to calculate the duration of each task and its sub-phases (reaching, manipulation, transport, release and return). A jerk index was computed to quantify movement smoothness. For each parameter, z-scores were calculated to analyze the deviation from normative data. MS subjects were clinically assessed with ARAT score, Nine-Hole Peg test (9HPT) and Fahn Tremor Rating Scale (FTRS).
ARAT tasks executed by MS patients were significantly slower (duration increase: 70%) and less smooth (jerk increase: 16%) with respect to controls. These anomalies were mainly related to manipulation, transport and release sub-movements, with the former showing the greatest alterations. A statistically significant decrease in movement velocity and smoothness was also noticed in patients with normal ARAT score. Z-scores related to duration and jerk were strongly correlated with ARAT rating (r < -0.80, p < 0.001) and 9HPT (r < -0.75, p < 0.001) and were significantly different among MS sub-groups with different levels of arm impairments (p < 0.001). Moreover, Z-score related to manipulation-phase jerk was significantly correlated with the FTRS rating of intention tremor (r = 0.84, p < 0.001).
The present study showed that the proposed method is able to discriminate between control and MS groups and to reveal subtle arm alterations not detectable from ARAT score. Validity was shown by high correlations between instrumental variables and clinical ratings. These results suggested that instrumented ARAT could be a valid quick and easy-to-use method for a sensitive quantification of arm function in MS. Inclusion of finger-mounted sensors could complement present findings and provide further indications about hand function in MS.
多发性硬化症（MS）患者的手臂功能障碍通常采用临床量表进行评估，例如动作研究手臂测试（ARAT），该量表可评估患者处理和搬运较小和较大物体的能力。ARAT 可全面评估上肢功能，因为它同时考虑了近端手臂和手部，但存在主观性和对轻度损伤不敏感的问题。在这项研究中，提出了一种带仪器的 ARAT 来克服这些局限性，并补充 MS 患者手臂功能的评估。
12 名健康志愿者和 21 名 MS 患者佩戴单个腕部惯性传感器进行 ARAT。使用加速度计和陀螺仪信号来计算每个任务及其子阶段（伸展、操作、运输、释放和返回）的持续时间。计算加加速度指标来量化运动的平滑度。为每个参数计算 z 分数，以分析与参考数据的偏差。MS 患者还接受了 ARAT 评分、九孔插板测试（9HPT）和震颤分级量表（FTRS）的临床评估。
与对照组相比，MS 患者执行 ARAT 任务时明显较慢（持续时间增加：70%）且运动不平稳（加加速度增加：16%）。这些异常主要与操作、运输和释放等子运动有关，而前两者表现出最大的改变。在 ARAT 评分正常的患者中，也观察到运动速度和平稳度的统计学显著下降。与持续时间和加加速度相关的 z 分数与 ARAT 评分（r < -0.80，p < 0.001）和 9HPT（r < -0.75，p < 0.001）高度相关，并且在不同手臂损伤程度的 MS 亚组之间存在显著差异（p < 0.001）。此外，与操作阶段加加速度相关的 z 分数与震颤分级量表的意向震颤评分显著相关（r = 0.84，p < 0.001）。
本研究表明，该方法能够区分对照组和 MS 组，并揭示 ARAT 评分无法检测到的微妙手臂变化。仪器变量与临床评分之间的高度相关性表明该仪器 ARAT 可能是一种有效的、快速、易于使用的方法，用于敏感地量化 MS 患者的手臂功能。包含手指安装的传感器可以补充目前的发现，并提供有关 MS 患者手部功能的进一步信息。
