OBJECTIVE Freezing phenomena in idiopathic Parkinson's disease (PD) constitute an important unaddressed therapeutic need. Changes in cortical neurophysiological signatures may precede a single freezing episode and indicate the evolution of abnormal motor network processes. Here, we hypothesize that the movement-related power modulation in the beta-band observed during regular finger tapping, deteriorates in the transition period before upper limb freezing (ULF). METHODS We analyzed a 36-channel EEG of 13 patients with PD during self-paced repetitive tapping of the right index finger. In offline analysis, we compared the transition period immediately before ULF ('transition') with regular tapping regarding movement-related power modulation and interregional phase synchronization. RESULTS From time-frequency analyses, we observed that the tap cycle related beta-band power modulation over the left sensorimotor area was diminished in the transition period before ULF. Furthermore, increased beta-band power was observed in the transition period compared to regular tapping centered over the left centro-parietal and right frontal areas. Phase synchronization between the left fronto-parietal areas and the left sensorimotor area was elevated during transition compared to regular tapping. CONCLUSION Together, these results indicate that diminished beta band power modulation and increased phase synchronization precede ULF. SIGNIFICANCE We demonstrate that pathological cortical motor processing is present in the transition phase from regular tapping to an ULF episode.

中文翻译：

---

重复敲击和上肢冻结之间的过渡显示与运动相关的 β 波段调制受损

目的 特发性帕金森病 (PD) 中的冻结现象构成了重要的未解决的治疗需求。皮层神经生理学特征的变化可能发生在一次冰冻发作之前，并表明异常运动网络过程的演变。在这里，我们假设在常规手指敲击期间观察到的 β 波段中与运动相关的功率调制在上肢冻结 (ULF) 之前的过渡期恶化。方法我们分析了 13 名 PD 患者在右手食指自定节奏重复敲击期间的 36 通道 EEG。在离线分析中，我们将 ULF（“过渡”）之前的过渡期与关于运动相关功率调制和区域间相位同步的常规攻丝进行了比较。结果来自时频分析，我们观察到，在 ULF 之前的过渡期内，左感觉运动区域上与抽头周期相关的 β 波段功率调制减弱。此外，与以左侧中央顶叶和右侧额叶区域为中心的常规敲击相比，在过渡期观察到了增加的 β 波段功率。与常规敲击相比，左额顶叶区域和左感觉运动区域之间的相位同步在过渡期间升高。结论 总之，这些结果表明，在 ULF 之前，β 波段功率调制减少和相位同步增加。意义我们证明了病理性皮层运动处理存在于从常规敲击到 ULF 发作的过渡阶段。