Choosing Strategies to Deal with Artifactual EEG Data in Children with Cognitive Impairment

Abstract

Rett syndrome is a disease that involves acute cognitive impairment and, consequently, a complex and varied symptomatology. This study evaluates the EEG signals of twenty-nine patients and classify them according to the level of movement artifact. The main goal is to achieve an artifact rejection strategy that performs well in all signals, regardless of the artifact level. Two different methods have been studied: one based on the data distribution and the other based on the energy function, with entropy as its main component. The method based on the data distribution shows poor performance with signals containing high amplitude outliers. On the contrary, the method based on the energy function is more robust to outliers. As it does not depend on the data distribution, it is not affected by artifactual events. A double rejection strategy has been chosen, first on a motion signal (accelerometer or EEG low-pass filtered between 1 and 10 Hz) and then on the EEG signal. The results showed a higher performance when working combining both artifact rejection methods. The energy-based method, to isolate motion artifacts, and the data-distribution-based method, to eliminate the remaining lower amplitude artifacts were used. In conclusion, a new method that proves to be robust for all types of signals is designed.

Methods for motion artifact reduction in online brain-computer interface experiments: a systematic review

“…It was shown by Tost et al ( 2021 ) and Fló et al ( 2022 ) that a parallelization of two or more streams within a pipeline with different preprocessing could increase the robustness and performance. Some authors have investigated the incorporation of accelerometer data into the pipeline and found a phase shift between the acceleration of the head.…”

Lattice layout and optimizer effect analysis for generating optimal transcranial electrical stimulation (tES) montages through the metaheuristic L1L1 method

“…The corresponding electric potential from the now-limited montage with channels y ℓ is normalized to meet the intended maximum current injection μ value while the remaining electrodes are opted out of further calculations. We constraint the total number of active electrodes available to ℓ = 20 inspired by commercial tES systems (Roy et al, 2019 ; Tost et al, 2021 ).…”

Atypical brain responses to 40‐Hz click trains in girls with Rett syndrome: Auditory steady‐state response and sustained wave

“…Outlier epochs were removed from each participant's data if the amplitude exceeded three SDs from the average; this procedure was cycled until no value in the range of three SD was found. This method was successfully implicated in previous research for children with RTT 9,48,49 and allows the removal of eye blinks and other artificial nonbrain activity such as teeth grinding, motion, and external noise if they are not occurring during substantial time of recording, which never occurred for our participants. The remaining epochs were averaged for each patient.…”