Yogatheesan Varatharajah

Research Interests

• Neurological Diseases
• Personalized Medicine
• Deep Learning
• Graphical Models
• Neural Engineering
• Machine Learning for Healthcare

Research Statement

I am broadly interested in health data analytics, machine learning, and computational neuroscience. Specifically, I am interested in developing domain-guided machine learning models for health data analytics, with specific applications in neurological diseases. My research is experimental in nature, with firm foundations in signal processing, machine learning, probabilistic graphical models, statistics, algorithms, and fundamental neuroscience.

Undergraduate Research Opportunities

I am available to mentor motivated undergraduates interested in machine learning and healthcare.

Primary Research Area

• Physiological systems - Neural engineering (general)

Research Areas

• Big Data
• Neural engineering (general)
• Statistical learning

Selected Articles in Journals

• Nejedly, Petr, Vaclav Kremen, Vladimir Sladky, Mona Nasseri, Hari Guragain, Petr Klimes, Jan Cimbalnik, Yogatheesan Varatharajah, Benjamin H. Brinkmann, and Gregory A. Worrell. "Deep-learning for seizure forecasting in canines with epilepsy." Journal of neural engineering 16, no. 3 (2019): 036031.
• Weiss, Shennan Aibel, Brent Berry, Inna Chervoneva, Zachary Waldman, Jonathan Guba, Mark Bower, Michal Kucewicz et al. "Visually validated semi-automatic high-frequency oscillation detection aides the delineation of epileptogenic regions during intra-operative electrocorticography." Clinical Neurophysiology 129, no. 10 (2018): 2089-2098.
• Varatharajah Y, Ramanan VK, Iyer R, Vemuri P. Predicting Short-term MCI-to-AD Progression Using Imaging, CSF, Genetic Factors, Cognitive Resilience, and Demographics. Sci Rep. 2019 Feb 19;9(1):2235. PubMed PMID: 30783207; PubMed Central PMCID: PMC6381141.
• Saboo KV, Varatharajah Y, Berry BM, Kremen V, Sperling MR, Davis KA, Jobst BC, Gross RE, Lega B, Sheth SA, Worrell GA, Iyer RK, Kucewicz MT. Unsupervised machine-learning classification of electrophysiologically active electrodes during human cognitive task performance. Sci Rep. 2019 Nov 22;9(1):17390. PubMed PMID: 31758077; PubMed Central PMCID: PMC6874617.
• Varatharajah Y, Iyer RK, Berry BM, Worrell GA, Brinkmann BH. Seizure Forecasting and the Preictal State in Canine Epilepsy. Int J Neural Syst. 2017 Feb;27(1):1650046. PubMed PMID: 27464854; NIHMSID: NIHMS845218; PubMed Central PMCID: PMC5288735.
• Varatharajah Y, Berry B, Cimbalnik J, Kremen V, Van Gompel J, Stead M, Brinkmann B, Iyer R, Worrell G. Integrating artificial intelligence with real-time intracranial EEG monitoring to automate interictal identification of seizure onset zones in focal epilepsy. J Neural Eng. 2018 Aug;15(4):046035. PubMed PMID: 29855436; NIHMSID: NIHMS979275; PubMed Central PMCID: PMC6108188.
• Varatharajah, Y., Joseph, B., Brinkmann, B., Morita‐Sherman, M., Fitzgerald, Z., Vegh, D., Nair, D., Burgess, R., Cendes, F., Jehi, L. and Worrell, G., 2022. Quantitative analysis of visually reviewed normal scalp EEG predicts seizure freedom following anterior temporal lobectomy. Epilepsia, 63(7), pp.1630-1642.
• Saboo, K.V., Hu, C., Varatharajah, Y., Przybelski, S.A., Reid, R.I., Schwarz, C.G., Graff-Radford, J., Knopman, D.S., Machulda, M.M., Mielke, M.M. and Petersen, R.C., 2022. Deep learning identifies brain structures that predict cognition and explain heterogeneity in cognitive aging. NeuroImage, 251, p.119020.
• Saboo, K.V., Balzekas, I., Kremen, V., Varatharajah, Y., Kucewicz, M., Iyer, R.K. and Worrell, G.A., 2021. Leveraging electrophysiologic correlates of word encoding to map seizure onset zone in focal epilepsy: Task‐dependent changes in epileptiform activity, spectral features, and functional connectivity. Epilepsia, 62(11), pp.2627-2639.
• Varatharajah, Y., Berry, B., Joseph, B., Balzekas, I., Pal Attia, T., Kremen, V., Brinkmann, B., Iyer, R. and Worrell, G., 2021. Characterizing the electrophysiological abnormalities in visually reviewed normal EEGs of drug-resistant focal epilepsy patients. Brain Communications, 3(2), p.fcab102.
• Varatharajah, Y. and Berry, B., 2022. A contextual-bandit-based approach for informed decision-making in clinical trials. Life, 12(8), p.1277.

Articles in Conference Proceedings

• Gupta, T., Wagh, N., Rawal, S., Berry, B., Worrell, G. and Varatharajah, Y., 2022. Tensor Decomposition of Large-scale Clinical EEGs Reveals Interpretable Patterns of Brain Physiology. In 2023 11th International IEEE/EMBS Conference on Neural Engineering (NER), IEEE, 2023.
• Wagh, N., Wei, J., Rawal, S., Berry, B.M. and Varatharajah, Y., 2022. Evaluating Latent Space Robustness and Uncertainty of EEG-ML Models under Realistic Distribution Shifts. Advances in Neural Information Processing Systems, 35, pp.21142-21156.
• Wagh, N., Wei, J., Rawal, S., Berry, B., Barnard, L., Brinkmann, B., Worrell, G., Jones, D. and Varatharajah, Y., 2021, November. Domain-guided self-supervision of eeg data improves downstream classification performance and generalizability. In Machine Learning for Health (pp. 130-142). PMLR.
• Rawal, S. and Varatharajah, Y., 2021, December. Score-it: A machine learning framework for automatic standardization of eeg reports. In 2021 IEEE Signal Processing in Medicine and Biology Symposium (SPMB) (pp. 1-4). IEEE.
• N. Wagh, Y. Varatharajah, EEG-GCNN: Augmenting Electroencephalogram-based Neurological Disease Diagnosis using a Domain-guided Graph Convolutional Neural Network, Accepted for publication, ML4H Workshop, Thirty-fourth Conference on Neural Information Processing Systems 2020.
• Varatharajah, Yogatheesan, Haotian Chen, Andrew Trotter, and Ravishankar Iyer. "A Dynamic Human-in-the-loop Recommender System for Evidence-based Clinical Staging of COVID-19.", ACM RecSys Workshop on Health Recommender Systems, 2020.
• Varatharajah, Yogatheesan, Brent Berry, Boney Joseph, Irena Balzekas, Vaclav Kremen, Benjamin Brinkmann, Gregory Worrell, and Ravishankar Iyer. "Electrophysiological Correlates of Brain Health Help Diagnose Epilepsy and Lateralize Seizure Focus." In 2020 42nd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), pp. 3460-3464. IEEE, 2020.
• Saboo, Krishnakant, Chang Hu, Yogatheesan Varatharajah, Prashanthi Vemuri, and Ravishankar Iyer. "Predicting Longitudinal Cognitive Scores Using Baseline Imaging and Clinical Variables." In 2020 IEEE 17th International Symposium on Biomedical Imaging (ISBI), pp. 1326-1330. IEEE, 2020.
• Saboo, Krishnakant V., Yogatheesan Varatharajah, Brent M. Berry, Michael R. Sperling, Richard Gorniak, Kathryn A. Davis, Barbara C. Jobst et al. "A Computationally Efficient Model for Predicting Successful Memory Encoding Using Machine-Learning-based EEG Channel Selection." In 2019 9th International IEEE/EMBS Conference on Neural Engineering (NER), pp. 323-327. IEEE, 2019.
• Varatharajah, Yogatheesan, Krishnakant Saboo, Ravishankar Iyer, Scott Przybelski, Christopher Schwarz, Ronald Petersen, Clifford Jack, and Prashanthi Vemuri. "A joint model for predicting structural and functional brain health in elderly individuals." In 2019 IEEE International Conference on Bioinformatics and Biomedicine (BIBM), pp. 1657-1664. IEEE, 2019.
• Varatharajah, Yogatheesan, Sujeeth Baradwaj, Atilla Kiraly, Diego Ardila, Ravishankar Iyer, Shravya Shetty, and Kai Kohlhoff. "Predicting brain age using structural neuroimaging and deep learning." bioRxiv (2018): 497925.
• Varatharajah, Yogatheesan, Brent Berry, Sanmi Koyejo, and Ravishankar Iyer. "A Contextual-bandit-based Approach for Informed Decision-making in Clinical Trials." arXiv preprint arXiv:1809.00258 (2018).
• Varatharajah, Yogatheesan, Brent M. Berry, Zbigniew T. Kalbarczyk, Benjamin H. Brinkmann, Gregory A. Worrell, and Ravishankar K. Iyer. "Inter-ictal seizure onset zone localization using unsupervised clustering and bayesian filtering." In 2017 8th International IEEE/EMBS Conference on Neural Engineering (NER), pp. 533-539. IEEE, 2017.
• Varatharajah, Yogatheesan, Min Jin Chong, Krishnakant Saboo, Brent Berry, Benjamin Brinkmann, Gregory Worrell, and Ravishankar Iyer. "EEG-GRAPH: A factor-graph-based model for capturing spatial, temporal, and observational relationships in electroencephalograms." In Advances in Neural Information Processing Systems, pp. 5371-5380. 2017.

Patents

• Berry, Brent M., Gary C. Sieck, Gregory A. Worrell, Benjamin H. Brinkmann, Yogatheesan Varatharajah, Vaclav Kremen, Ravishankar Krishnan Iyer, Zbigniew Kalbarczyk, and Jan Cimbalnik. "Seizure onset zone localization." U.S. Patent Application 16/616,771, filed June 11, 2020.

Honors

• NSF CISE Research Initiation Award (CRII)
• Coordinated Science Laboratory Ph.D. Thesis Award (2021)
• Young Investigator Award, American Epilepsy Society (2020)
• Rambus Computer Engineering Fellowship (2018)
• Fellowship of the Mayo Clinic - Illinois Alliance for Technology-based Healthcare Research (2016)

Research Honors

• Best Poster Award, Machine Learning for Health Symposium (2021)
• Best Paper Award, IEEE Signal Processing in Medicine and Biology Conference (2021)