BACKGROUND Camptocormia is a disabling complication of Parkinson's disease (PD), but its pathophysiology is poorly elucidated. Depending on the fulcrum of forward trunk flexion, two subtypes have been defined, upper (UCC) and lower camptocormia, the former being much more frequent. The aim of the study was to explore possible pathophysiological mechanisms of PD-related UCC. METHODS Ten PD patients with UCC (UCC-PD) and ten PD patients without camptocormia (NoUCC-PD) underwent simultaneous electromyography (EMG) of thoracic paraspinal (TPS), obliquus externus abdominis (OEA), rectus abdominis (RA), and iliopsoas (IP) muscles during relaxed standing (both groups) and trunk realignment (UCC-PD group). Quantitative EMG and magnetic resonance imaging (MRI) of TPS muscles were also performed. RESULTS UCC-PD patients showed hyperactivity of TPS and OEA muscles in quiet stance. During voluntary trunk extension, hyperactivity of OEA muscles persisted, thus revealing a co-contraction of flexor and extensor trunk muscles. Motor unit potentials (MUP) of TPS muscles showed shorter duration (p = 0.005) and lower amplitude (p = 0.004) in UCC-PD than in NoUCC-PD patients. MRI did not detect significant between-group differences in the cross-sectional area and fat fraction of TPS muscles, although the latter was higher in the UCC-PD than in the NoUCC-PD group at all thoracic levels. CONCLUSION Our findings suggest that hyperactivity of OEA might sustain UCC in PD. Concurrent mild myopathic changes in TPS muscles in PD with UCC may be secondary to muscle disuse but nevertheless may contribute to abnormal trunk posture.

中文翻译：

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帕金森氏病中的上坎皮层：中枢和外周病理生理机制的神经生理学和影像学发现。

背景技术喜树皮病是帕金森氏病（PD）的致残性并发症，但其病理生理学尚不清楚。根据前躯干屈曲的支点，已定义了两种亚型，上部（UCC）和下部坎皮层，前者更为频繁。该研究的目的是探讨PD相关UCC的可能的病理生理机制。方法对10例UCC的PD患者（UCC-PD）和10例无坎皮病的PD患者（NoUCC-PD）进行胸椎旁（TPS），腹外斜肌（OEA），腹直肌（RA）和，肌同时肌电图（EMG） （IP）放松站立时（两组）和躯干调整（UCC-PD组）时的肌肉。还进行了TPS肌肉的定量EMG和磁共振成像（MRI）。结果UCC-PD患者在安静的姿势下表现出TPS和OEA肌肉过度活跃。在自愿性躯干伸展过程中，OEA肌肉过度活动持续存在，从而揭示了屈伸和伸肌躯干肌肉的共收缩。与NoUCC-PD患者相比，UCC-PD患者的TPS肌肉运动单位电位（MUP）持续时间较短（p = 0.005），幅度较低（p = 0.004）。MRI未检测到TPS肌肉的横截面积和脂肪分数存在明显的组间差异，尽管在所有胸腔水平上，UCC-PD中的后者高于NoUCC-PD组中的差异。结论我们的发现表明，OEA过度活跃可能会维持PD中的UCC。患有UCC的PD患者，TPS肌肉同时出现轻度肌病性改变可能是继发于肌肉停用的原因，但是可能导致躯干姿势异常。