https://doi.org/10.1140/epjs/s11734-024-01409-7
Regular Article
EEG correlates of the tactile perception of patients in a vegetative state and coma: a step towards AI-based classification of unconscious states
1
Laboratory of Human Higher Nervous Activity, FSBSI Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 5A Butlerova St., 117485, Moscow, Russian Federation
2
Skolkovo Institute of Science and Technology, 121205, Moscow, Russia
3
Tactile Communication Laboratory, Pushkin State Russian Language Institute, 6 Akademika Volgina St., 117485, Moscow, Russian Federation
4
Federal State Autonomous Institution N. N. Burdenko National Medical Research Center of Neurosurgery of the Ministry of Health of the Russian Federation, Moscow, Russian Federation
Received:
6
October
2024
Accepted:
14
November
2024
Published online:
3
December
2024
We aimed to evaluate changes in EEG power upon presentation of pleasant and unpleasant C-tactile stimulation to patients in acute and subacute coma, as well as in the vegetative state. The study involved 50 unconscious patients and 35 participants in the control group aged 21–46 years. The study included the registration of a background EEG with eyes closed for 1–2 min, as well as after presentation of tactile stimulation of two types (stroking with a soft brush, stroking with a hard brush) at a constant speed of 2–4 cm/s on the outer surface of the right forearm. The subjective assessment of stimuli by conscious subjects was also rated. EEG spectral power indices were evaluated in 19 sub-bands with a bandwidth of 1 Hz (2–20 Hz). The study revealed two types of responses to tactile stimulation: the first type is not specific to the type of tactile stimulation, accompanied by an increase in alpha-rhythm power (10–12 Hz) in subacute and vegetative states and beta-rhythm (14–20 Hz)—only in vegetative; the second type of reaction is accompanied by a decrease in theta rhythm power (4–6 Hz) in the central regions in response to stimulation of the c-tactile system with a soft brush and is observed only in patients in the subacute period. The selective response to stimulation of the c-tactile system observed in patients in the subacute phase of the coma was manifested on the EEG by a decrease in the theta rhythm power in the central regions. The increase in beta-rhythm power serves as a universal indicator of sensorimotor activation and intention to movement and is most pronounced in patients in a vegetative state. An increase in alpha-rhythm power shows the activation of working memory, as well as the suppression of other processes not related to the perception of tactile effects and is most pronounced in patients in the subacute phase and vegetative state. The results may be used for further development of AI-based tools for evaluation of the consciousness level and outcome prediction.
Copyright comment Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
© The Author(s), under exclusive licence to EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature 2024
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
