Bianchi Anna M
Department of Biomedical Engineering, Politecnico di Milano, IIT Unit, Italy.
Annu Int Conf IEEE Eng Med Biol Soc. 2010;2010:1710-3. doi: 10.1109/IEMBS.2010.5626850.
The functional connectivity of the brain is investigated through the study of multivariate autoregressive models (MVAR) applied to multichannel EEG recordings. After the identification of the model, different indices can be calculated that are able to quantify direct and indirect functional connections between cortical areas. These methodology is used for the investigation of possible connectivity alterations in patients after Traumatic Brain Injury (TBI) who suffered from Diffuse Assonal Injury (DAI). As one of main consequences of DAI are cognitive and attention impairment, the subjects underwent an attention test (Conners CPT) during EEG recording. In order to avoid spurious coherences, related to the volume effect of the head, a Laplacian transformation was applied to the data before connectivity evaluation. The MVAR was fitted to the different phases of the test and different indices were calculated. Even if the general connectivity is not different between patients and controls, differences were found in inter hemispheric connectivity. Both in beta and in gamma bands central electrodes C3 and C4 seem the main sources of activity that is directed mainly towards Fp1 and Fp2. Such connectivity is less intense in DAI subjects.
通过将多变量自回归模型（MVAR）应用于多通道脑电图记录来研究大脑的功能连接性。在识别模型之后，可以计算出不同的指标，这些指标能够量化皮质区域之间的直接和间接功能连接。该方法用于研究患有弥漫性轴索损伤（DAI）的创伤性脑损伤（TBI）患者可能存在的连接性改变。由于DAI的主要后果之一是认知和注意力受损，受试者在脑电图记录期间接受了注意力测试（康纳斯连续性能测试）。为了避免与头部体积效应相关的虚假相干性，在进行连接性评估之前，对数据应用了拉普拉斯变换。将MVAR拟合到测试的不同阶段并计算不同的指标。即使患者和对照组之间的总体连接性没有差异，但在半球间连接性方面发现了差异。在β和γ波段，中央电极C3和C4似乎是主要的活动源，主要指向Fp1和Fp2。这种连接性在DAI受试者中较弱。
