Background. Cervical dystonia (CD) is a neurological movement disorder characterized by involuntary contractions of the cervical musculature and is known to be associated with proprioceptive dysfunction in dystonic/nondystonic limbs. Objectives. We examined how neck botulinum neurotoxin (BoNT) injection affects wrist proprioception and the corresponding sensorimotor cortical activity in CD. Method. Wrist position sense acuity of the dominant (right) hand was evaluated in 15 CD and 15 control participants. Acuity measures were a psychophysical position sense discrimination threshold (DT; based on passive joint displacement) and joint position matching error (based on active movement). Cortical activity during the motor preparation period of the active joint position matching was examined using electroencephalography. Results. In their symptomatic state, patients demonstrated a significantly higher wrist proprioceptive DT, indicating an abnormal passive wrist position sense. Yet BoNT injections had no significant effect on this threshold. During active joint position matching, errors were significantly larger in patients, but this difference vanished after the administration of BoNT. Motor preparation of active wrist position matching was associated with a significantly higher rise of β-band (13-30 Hz) power over contralateral somatosensory-motor cortical areas in patients. This excessive cortical activity significantly declined post-BoNT. Conclusion. Wrist proprioceptive perception during passive/active movements is abnormal in CD. An excessive rise of premotor/motor cortical β-oscillations during motor planning is associated with this proprioceptive dysfunction. Neck BoNT injections normalized the cortical processing of proprioceptive information from nonsymptomatic limbs, indicating that local injections may affect the central mechanisms of proprioceptive function in CD.

中文翻译：

---

颈部肉毒杆菌神经毒素注射液对颈肌张力障碍患者本体感觉和躯体感觉运动皮层处理的影响

背景。颈肌张力障碍 (CD) 是一种神经运动障碍，其特征是颈肌不自主收缩，已知与肌张力障碍/非肌张力障碍肢体的本体感觉功能障碍有关。目标。我们研究了颈部肉毒杆菌神经毒素 (BoNT) 注射如何影响腕部本体感觉和 CD 中相应的感觉运动皮层活动。方法。在 15 名 CD 和 15 名对照参与者中评估了优势（右手）手的手腕位置感觉敏锐度。敏锐度测量是心理物理位置感觉辨别阈值（DT；基于被动关节位移）和关节位置匹配误差（基于主动运动）。使用脑电图检查主动关节位置匹配的运动准备期间的皮质活动。结果。在有症状的状态下，患者表现出明显更高的腕部本体感觉 DT，表明腕部被动位置感异常。然而，BoNT 注射对该阈值没有显着影响。在主动关节位置匹配期间，患者的误差明显更大，但在施用 BoNT 后这种差异消失了。主动腕部位置匹配的运动准备与患者对侧体感 - 运动皮层区域的 β 波段（13-30 Hz）功率显着升高相关。这种过度的皮质活动在 BoNT 后显着下降。结论。CD 患者被动/主动运动过程中的手腕本体感觉异常。运动规划期间运动前/运动皮质 β 振荡的过度增加与这种本体感觉功能障碍有关。