Ensemble multi-modal brain source localization using theory of evidence

The primary aim in pre-surgical evaluations in patients with neurological disorders such as epilepsy is determining the precise location of the cortical region responsible for the malfunctions which is called source localization. Different modalities unravel different views of brain activity. Combining these complementary aspects of the brain yields more accurate source localization. In this paper, a method is proposed for combining localization methods in different modalities based on the theory of evidence, the result of some localization methods in modalities are integrated using weights in accordance to their relative performance and are combined using Dempster's rule of combination and is used for the case of EEG and MEG combinatory source localization. The proposed method is evaluated on simulated realistic MEG and EEG data and in different noise and artifact levels and finds the zone of interest in a more accurate way. The AUC criterion is used as a metric for the evaluation. The proposed method results in better localization accuracy in terms of AUC showing the combination of modalities could lead to superior performance. Combining two modalities needs an exact knowledge of the phenomena happening in each modality, making the combination difficult. Here rather of combining EEG and MEG information at the initial phase, the results of some source localization techniques on both modalities are combined. In spite of the simplicity of use, the experimental results of combination showed improvement in epileptic source localization accuracy even in cases that one method shows poor performance. Using the proposed method any number of modalities can be combined without complex consideration and a better brain source localization could be obtained.

Automated summary

This paper proposes a method for combining source localization results from different modalities in pre-surgical evaluations for patients with neurological disorders. By integrating results using Dempster's rule of combination, the combined modalities show improved accuracy in brain source localization, even in cases of poor individual method performance.