Neuroscience Institute, Northwestern University, Chicago, IL 60611, USA.
J Neurosci Methods. 2011 Feb 15;195(2):151-60. doi: 10.1016/j.jneumeth.2010.11.021. Epub 2010 Dec 4.
In moderate to severely impaired stroke patients, single pulse TMS, with or without background facilitation, may not be able to evoke a motor response in muscles of the upper extremity, thereby hindering potential studies of stroke patients using TMS. Paired pulse TMS has been shown to facilitate responses in distal muscles of healthy subjects. In this study, our aim was to investigate thirteen muscles of the upper extremity in moderate to severely impaired stroke patients and determine the paired pulse interstimulus interval (ISI) that was optimal for facilitation of the TMS response.
We recruited 8 moderate to severely impaired stroke patients and 5 healthy controls. A hotspot was found that could activate the greatest number of the 13 target upper extremity muscles. 16 ISIs were tested.
In healthy controls, an ISI range of 3-50 ms in the left hemisphere and 8-40 ms in the right hemisphere was optimal for activating the contralateral arm. In the stroke patients, stimulation of the non-lesioned hemisphere at an ISI of 8-50 ms was optimal for contralateral responses, similar to the control subjects, while stimulation of the lesioned hemisphere had an optimal ISI range of 12-50 ms. Ipsilateral responses in the paretic limb were frequent and the optimal ISI range was much later than the contralateral responses in stroke or controls occurring at 25-40 ms.
In stroke and control subjects, across muscles and contralateral or ipsilateral pathways, an interstimulus interval of 25-40 ms was optimal to evoke a TMS response and resulted in the greatest degree of facilitation.
在中度至重度受损的中风患者中，单个脉冲 TMS，无论是否有背景刺激，可能都无法在上肢肌肉中引发运动反应，从而阻碍了使用 TMS 对中风患者进行的潜在研究。双脉冲 TMS 已被证明可以促进健康受试者的远端肌肉反应。在这项研究中，我们的目的是研究中度至重度受损的中风患者的 13 块上肢肌肉，并确定最佳的双脉冲刺激间隔（ISI）来促进 TMS 反应。
我们招募了 8 名中度至重度受损的中风患者和 5 名健康对照者。找到了一个热点，该热点可以激活最多的 13 个目标上肢肌肉。测试了 16 个 ISI。
在健康对照组中，左半球的 ISI 范围为 3-50ms，右半球的 ISI 范围为 8-40ms，是激活对侧手臂的最佳范围。在中风患者中，非病变半球的刺激在 8-50ms 的 ISI 下对产生对侧反应最佳，与对照组相似，而病变半球的刺激在 12-50ms 的 ISI 下具有最佳范围。患侧肢体的同侧反应很常见，最佳 ISI 范围比中风或对照组的对侧反应晚得多，发生在 25-40ms。
在中风和对照组中，跨肌肉和对侧或同侧通路，25-40ms 的刺激间隔是诱发 TMS 反应的最佳间隔，并且可以产生最大程度的易化作用。
