Classification of Phonological Categories in Imagined Speech using Phase Synchronization Measure

Panachakel, JT and Ramakrishnan, AG (2021) Classification of Phonological Categories in Imagined Speech using Phase Synchronization Measure. In: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, 1 - 5 November 2021, Virtual, Online, pp. 2226-2229.

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Abstract

Phonological categories in articulated speech are defined based on the place and manner of articulation. In this work, we investigate whether the phonological categories of the prompts imagined during speech imagery lead to differences in phase synchronization in various cortical regions that can be discriminated from the EEG captured during the imagination. Nasal and bilabial consonant are the two phonological categories considered due to their differences in both place and manner of articulation. Mean phase coherence (MPC) is used for measuring the phase synchronization and shallow neural network (NN) is used as the classifier. As a benchmark, we have also designed another NN based on statistical parameters extracted from imagined speech EEG. The NN trained on MPC values in the beta band gives classification results superior to NN trained on alpha band MPC values, gamma band MPC values and statistical parameters extracted from the EEG.Clinical relevance: Brain-computer interface (BCI) is a promising tool for aiding differently-abled people and for neurorehabilitation. One of the challenges in designing speech imagery based BCI is the identification of speech prompts that can lead to distinct neural activations. We have shown that nasal and blilabial consonants lead to dissimilar activations. Hence prompts orthogonal in these phonological categories are good choices as speech imagery prompts. © 2021 IEEE.

Item Type:	Conference Paper
Publication:	Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS
Publisher:	Institute of Electrical and Electronics Engineers Inc.
Additional Information:	The copyright for this article belongs to Institute of Electrical and Electronics Engineers Inc.
Keywords:	Chemical activation; Linguistics; Synchronization, Classification results; Cortical regions; Gamma band; In-phase; Network-based; Neural-networks; Phase coherence; Phase synchronization; Phase synchronization measures; Statistical parameters, Speech, brain computer interface; electroencephalography; human; imagination; speech, Brain-Computer Interfaces; Electroencephalography; Humans; Imagery, Psychotherapy; Imagination; Speech
Department/Centre:	Division of Electrical Sciences > Electrical Engineering
Date Deposited:	16 Feb 2023 10:39
Last Modified:	16 Feb 2023 10:39
URI:	https://eprints.iisc.ac.in/id/eprint/80533

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