Neuroscience Laboratory, Department of Neurology, China Medical University Hospital, Taiwan.
Clin Neurophysiol. 2010 Apr;121(4):622-30. doi: 10.1016/j.clinph.2009.12.014. Epub 2010 Jan 22.
Essential tremor (ET) is an involuntary postural oscillation. It is unclear to which extent motor cortical activity in preparation of volitional movement is abnormal in ET. We measured the Bereitschaftspotential (BP) to address this question.
Given the known influence of the cerebello-dentato-thalamo-cortical projection in the generation of the BP, patients were divided into two groups, defined by purely postural tremor (ET(PT)) or additional presence of intention tremor (ET(IT)) and compared to healthy controls. BP was recorded during self-paced rapid wrist extension movements.
The late BP (500-0 ms before movement onset) was increased over the mid-frontal area in ET(PT), whereas it was reduced over the mid-parietal area in ET(IT) when compared to healthy controls. In addition, the late BP was reduced over a widespread centro-parietal area in ET(IT) compared to ET(PT).
Findings suggest that presence vs. absence of cerebellar signs (intention tremor) in ET results in differential affection of volitional preparatory motor cortical activity. The BP increase in ET(PT) may indicate compensatory activity, whereas the widespread centro-parietal BP reduction in ET(IT) suggests dysfunction of the cerebello-dentato-thalamo-cortical projection.
Reduction of the late BP amplitude may serve as a surrogate marker for dysfunction of the cerebello-dentato-thalamo-cortical projection in ET.
特发性震颤（ET）是一种无意识的姿势性震颤。目前尚不清楚在 ET 中，准备意向性运动的运动皮质活动在多大程度上异常。我们测量了预备电位（BP）来解决这个问题。
鉴于已知的小脑齿状核丘脑皮质投射在 BP 产生中的影响，将患者分为两组，定义为单纯姿势性震颤（ET（PT））或伴有意向性震颤（ET（IT）），并与健康对照组进行比较。在自我调节的快速腕部伸展运动期间记录 BP。
与健康对照组相比，ET（PT）中额中区域的晚期 BP（运动起始前 500-0ms）增加，而 ET（IT）中顶中区域的晚期 BP 减少。此外，与 ET（PT）相比，ET（IT）中广泛的中顶区的晚期 BP 减少。
这些发现表明，ET 中是否存在小脑征象（意向性震颤）导致意向性预备运动皮质活动的差异受累。ET（PT）中的 BP 增加可能表明代偿性活动，而 ET（IT）中广泛的中顶区 BP 减少则表明小脑齿状核丘脑皮质投射的功能障碍。
晚期 BP 幅度的降低可能可作为 ET 中小脑齿状核丘脑皮质投射功能障碍的替代标志物。
