Igasaki Tomohiko, Takemoto Junya, Sakamoto Katsuya
Annu Int Conf IEEE Eng Med Biol Soc. 2018 Jul;2018:1911-1914. doi: 10.1109/EMBC.2018.8512673.
Motor imagery (MI) is divided into two types: kinesthetic (KMI) and visual (VMI). To estimate the MI that an examinee performs, event-related desynchronization (ERD) or event-related synchronization (ERS) is used to characterize KMI or VMI via electroencephalogram (EEG). However, no definitive method using ERD/ERS via EEG has been established yet to estimate the type of MI performed. This is because the MI performed by the examinee is not always the same as that instructed by the examiner. One of the reasons for this mismatch is the difficulty of MI, especially KMI. However, almost no reported studies have considered MI difficulty to estimate MI type. Therefore, in this study, we examined the relationship between MI difficulty and the ERD/ERS pattern corresponding to the type of MI in the case of single flexion of the right index finger (SFRIF). The results showed that for a subject who felt MI was less difficult, the α-band ERD value (αERD) at the electrode of the occipital area (O1 or O2 site) of the KMI instruction was significantly smaller than that of the VMI instruction. On the contrary, for a subject who felt MI was very difficult, αERD at the O1 or O2 site on the KMI instruction was similar to that of the VMI instruction. In addition, for the subject who felt MI was easy, the αERDs at the O1 or O2 site on the KMI and VMI instructions were similar to those on the movement execution (ME) and movement observation (MO) instructions, respectively. Therefore, in the case of SFRIF, it was suggested that MI difficulty could be estimated by ERD/ERS patterns in the occipital area. This was supported by referring to the ME and MO ERD/ERS patterns in the occipital area.
运动想象（MI）分为两种类型：动觉型（KMI）和视觉型（VMI）。为了评估受试者执行的运动想象，事件相关去同步化（ERD）或事件相关同步化（ERS）通过脑电图（EEG）来表征KMI或VMI。然而，尚未建立一种通过EEG使用ERD/ERS来估计所执行的运动想象类型的明确方法。这是因为受试者执行的运动想象并不总是与检查者指示的相同。这种不匹配的原因之一是运动想象的难度，尤其是KMI。然而，几乎没有已报道的研究考虑运动想象难度来估计运动想象类型。因此，在本研究中，我们研究了在右手食指单次弯曲（SFRIF）情况下，运动想象难度与对应运动想象类型的ERD/ERS模式之间的关系。结果表明，对于感觉运动想象难度较小的受试者，KMI指令下枕叶区域（O1或O2位点）电极处的α波段ERD值（αERD）显著小于VMI指令下的。相反，对于感觉运动想象非常困难的受试者，KMI指令下O1或O2位点的αERD与VMI指令下的相似。此外，对于感觉运动想象容易的受试者，KMI和VMI指令下O1或O2位点的αERD分别与运动执行（ME）和运动观察（MO）指令下的相似。因此，在SFRIF的情况下，表明可以通过枕叶区域的ERD/ERS模式来估计运动想象难度。这通过参考枕叶区域的ME和MO的ERD/ERS模式得到了支持。
