Time-Frequency Analysis of Scalp EEG With Hilbert-Huang Transform and Deep Learning

• Published in: IEEE journal of biomedical and health informatics Vol. 26; no. 4; pp. 1549 - 1559
• Main Authors: Zheng, Jingyi, Liang, Mingli, Sinha, Sujata, Ge, Linqiang, Yu, Wei, Ekstrom, Arne, Hsieh, Fushing
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.04.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Biomarkers; Brain; Brain Waves; Deep learing (DL); Deep Learning; EEG; Electroencephalography; Electroencephalography (EEG); Electroencephalography - methods; Empirical Mode Decomposition (EMD); Feature extraction; Frequency analysis; Frequency dependence; Hilbert transformation; Hilbert-Huang Transform (HHT); Humans; Machine learning; Measurement; Nervous system; Neuroimaging; Neurosciences; Oscillations; Oscillators; Peak frequency; Scalp; Signal classification; Subject-specific frequency bands; Task analysis; Time-frequency analysis; Variation; Wavelet Analysis
• DOI: 10.1109/JBHI.2021.3110267
• ISSN: 2168-2194; 2168-2208

Electroencephalography (EEG) is a brain imaging approach that has been widely used in neuroscience and clinical settings. The conventional EEG analyses usually require pre-defined frequency bands when characterizing neural oscillations and extracting features for classifying EEG signals. However, neural responses are naturally heterogeneous by showing variations in frequency bands of brainwaves and peak frequencies of oscillatory modes across individuals. Fail to account for such variations might result in information loss and classifiers with low accuracy but high variation across individuals. To address these issues, we present a systematic time-frequency analysis approach for analyzing scalp EEG signals. In particular, we propose a data-driven method to compute the subject-specific frequency bands for brain oscillations via Hilbert-Huang Transform, lifting the restriction of using fixed frequency bands for all subjects. Then, we propose two novel metrics to quantify the power and frequency aspects of brainwaves represented by sub-signals decomposed from the EEG signals. The effectiveness of the proposed metrics are tested on two scalp EEG datasets and compared with four commonly used features sets extracted from wavelet and Hilbert-Huang Transform. The validation results show that the proposed metrics are more discriminatory than other features leading to accuracies in the range of 94.93% to 99.84%. Besides classification, the proposed metrics show great potential in quantification of neural oscillations and serving as biomarkers in the neuroscience research.