Warren Alpert Medical School, Brown University, Providence, RI, USA.
Exp Brain Res. 2010 Mar;201(2):331-8. doi: 10.1007/s00221-009-2046-4. Epub 2009 Oct 21.
Deep brain stimulation (DBS) of the ventrolateral thalamus is a highly effective procedure for the treatment of essential tremor (ET). The regularity of repetitive, self-paced finger tapping is known to be abnormal in patients with ET and improved following DBS. However, the more complex timing that underlies force development in the hands in ET and after DBS has not been evaluated. In this pilot study, we assessed precision grip performance in seven ET subjects before and after 5 months of DBS. Ten healthy controls were also studied. ET subjects showed a significant increase in preload duration (235 +/- 145 vs. 82 +/- 49 ms) and peak negative load (-0.524 +/- 0.35 vs. -0.174 +/- 0.14 N) during grip-lift compared with healthy subjects. No difference in load duration was observed between the groups. Following DBS, the magnitude of the peak negative load was significantly reduced (P = 0.03). In contrast, the duration of the load phase was worsened (non-significant) after DBS. We conclude that defects in the control of distal musculature necessary for establishing a stable grip exist in ET, whereas proximal muscles necessary for object lift-off remain relatively intact. Further, synergy paradigms governing grip-lift coordination may also be impaired. Although DBS is successful in alleviating tremor in ET, it produces only a partial restoration of normal precision grip.
脑深部电刺激（DBS）于腹外侧丘脑是治疗原发性震颤（ET）的一种非常有效的方法。已知 ET 患者的重复、自我调节的手指敲击的规律性异常，并且在 DBS 后得到改善。然而，在 ET 和 DBS 后，手部力量发展所依据的更复杂的时间关系尚未得到评估。在这项初步研究中，我们在 DBS 前和 5 个月后评估了 7 名 ET 患者的精确握力表现。还研究了 10 名健康对照者。与健康受试者相比，ET 患者在握力提起过程中显示出明显的预加载持续时间（235 +/- 145 与 82 +/- 49 毫秒）和峰值负载（-0.524 +/- 0.35 与-0.174 +/- 0.14 N）增加。组间无负载持续时间差异。在 DBS 后，峰值负载的幅度显著降低（P = 0.03）。相比之下，DBS 后负载阶段的持续时间恶化（无显著差异）。我们得出结论，在 ET 中存在建立稳定握力所需的远端肌肉控制缺陷，而对于物体提升所需的近端肌肉则相对完整。此外，用于握力提升协调的协同作用模式也可能受损。尽管 DBS 在缓解 ET 震颤方面非常成功，但它仅部分恢复了正常的精确握力。
