Objective

Early postural instability (PI) is a red flag for the diagnosis of Parkinson’s disease (PD). Several patients, however, fall within the first three years of disease, particularly when turning. We investigated whether PD patients, without clinically overt PI, manifest abnormal reactive postural responses to ecological perturbations resembling turning.

Methods

Fifteen healthy subjects and 20 patients without clinically overt PI, under and not under L-Dopa, underwent dynamic posturography during axial rotations around the longitudinal axis, provided by a robotic mechatronic platform. We measured reactive postural responses, including body displacement and reciprocal movements of the head, trunk, and pelvis, by using a network of three wearable inertial sensors.

Results

Patients showed higher body displacement of the head, trunk and pelvis, and lower joint movements at the lumbo-sacral junction than controls. Conversely, movements at the cranio-cervical junction were normal in PD. L-Dopa left reactive postural responses unchanged.

Conclusions

Patients with PD without clinically overt PI manifest abnormal reactive postural responses to axial rotations, unresponsive to L-Dopa. The biomechanical model resulting from our experimental approach supports novel pathophysiological hypotheses of abnormal axial rotations in PD.

Significance

PD patients without clinically overt PI present subclinical balance impairment during axial rotations, unresponsive to L-Dopa.

中文翻译：

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帕金森病的早期平衡障碍：来自机器人辅助轴向旋转的证据

客观的

早期姿势不稳 (PI) 是诊断帕金森病 (PD) 的危险信号。然而，一些患者在疾病的前三年内就属于这种情况，特别是在转身时。我们调查了没有临床明显 PI 的 PD 患者是否对类似转动的生态扰动表现出异常的反应性姿势反应。

方法

15 名健康受试者和 20 名没有临床明显 PI 的患者，在左旋多巴下和不在左旋多巴下，在机器人机电一体化平台提供的绕纵轴轴向旋转期间接受动态姿势描记术。我们通过使用三个可穿戴惯性传感器的网络测量了反应性姿势反应，包括身体位移和头部、躯干和骨盆的往复运动。

结果

与对照组相比，患者的头部、躯干和骨盆的身体位移更大，腰骶连接处的关节运动更低。相反，PD 中颅颈交界处的运动是正常的。左旋多巴使反应性姿势反应保持不变。

结论

没有临床明显 PI 的 PD 患者表现出对轴向旋转的异常反应性姿势反应，对左旋多巴无反应。我们的实验方法产生的生物力学模型支持 PD 中异常轴向旋转的新病理生理学假设。

意义

没有临床明显 PI 的 PD 患者在轴向旋转期间呈现亚临床平衡受损，对左旋多巴无反应。