Pancani Silvia, Tindale Wendy, Shaw Pamela J, McDermott Christopher J, Mazzà Claudia
Department of Mechanical Engineering, University of Sheffield, Sheffield, United Kingdom.
INSIGNEO Institute for in silico Medicine, University of Sheffield, Sheffield, United Kingdom.
PLoS One. 2017 Jan 9;12(1):e0169019. doi: 10.1371/journal.pone.0169019. eCollection 2017.
Neck muscle weakness and head drop are well recognised in patients with Amyotrophic lateral sclerosis (ALS), but an objective characterisation of the consequent head movement impairment is lacking. The aim of this study was to quantitatively characterise head movements in ALS compared to aged matched controls.
We evaluated two groups, one of thirteen patients with ALS and one of thirteen age-matched controls, during the execution of a series of controlled head movements, performed while wearing two inertial sensors attached on the forehead and sternum, respectively. We quantified the differences between the two groups from the sensor data using indices of velocity, smoothness and movement coupling (intended as a measure of undesired out of plane movements).
Results confirmed a general limitation in the ability of the ALS patients to perform and control head movements. High inter-patient variability was observed due to a wide range of observed functional impairment levels. The ability to extend the head backward and flex it laterally were the most compromised, with significantly lower angular velocity (P < 0.05, Cohen's d > 0.8), reduced smoothness and greater presence of coupled movements with respect to the controls. A significant reduction of angular velocity (P < 0.05, Cohen's d > 0.8) in extension, axial rotation and lateral flexion was observed when patients were asked to perform the movements as fast as possible.
This pilot study is the first study providing a functional objective quantification of head movements in ALS. Further work involving different body areas and correlation with existing methods of evaluating neuromuscular function, such as dynamometry and EMG, is needed to explore the use of this approach as a marker of disease progression in ALS.
肌萎缩侧索硬化症（ALS）患者的颈部肌肉无力和头部下垂现象已广为人知，但对于由此导致的头部运动障碍，目前仍缺乏客观的特征描述。本研究的目的是定量描述ALS患者与年龄匹配的对照组相比的头部运动情况。
我们评估了两组对象，一组是13例ALS患者，另一组是13例年龄匹配的对照组，在他们分别佩戴两个惯性传感器（一个附着在前额，另一个附着在胸骨上）进行一系列受控头部运动时进行观察。我们使用速度、平滑度和运动耦合指标（作为对不期望的平面外运动的一种度量）从传感器数据中量化两组之间的差异。
结果证实了ALS患者执行和控制头部运动的能力普遍受限。由于观察到的功能损害水平范围广泛，患者之间存在较高的变异性。头部向后伸展和向侧面弯曲的能力受损最为严重，与对照组相比，其角速度显著降低（P < 0.05，科恩d值> ），平滑度降低，耦合运动更多。当要求患者尽可能快地进行运动时，观察到伸展、轴向旋转和侧屈时的角速度显著降低（P < 0.05，科恩d值> ）。
这项初步研究是第一项提供ALS患者头部运动功能客观量化的研究。需要进一步开展涉及不同身体部位的工作，并将其与现有的评估神经肌肉功能的方法（如测力计和肌电图）进行关联，以探索将这种方法用作ALS疾病进展标志物 的用途。 0.8 0.8
