Article (Scientific journals)
A fast and general method to empirically estimate the complexity of brain responses to transcranial and intracranial stimulations.
Comolatti, Renzo; Pigorini, Andrea; Casarotto, Silvia et al.
2019In Brain Stimulation, 12 (5), p. 1280-1289
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Keywords :
Brain complexity; Consciousness; EEG; Intracranial; Single pulse electrical stimulation; Transcranial magnetic stimulation
Abstract :
[en] BACKGROUND: The Perturbational Complexity Index (PCI) was recently introduced to assess the capacity of thalamocortical circuits to engage in complex patterns of causal interactions. While showing high accuracy in detecting consciousness in brain-injured patients, PCI depends on elaborate experimental setups and offline processing, and has restricted applicability to other types of brain signals beyond transcranial magnetic stimulation and high-density EEG (TMS/hd-EEG) recordings. OBJECTIVE: We aim to address these limitations by introducing PCI(ST), a fast method for estimating perturbational complexity of any given brain response signal. METHODS: PCI(ST) is based on dimensionality reduction and state transitions (ST) quantification of evoked potentials. The index was validated on a large dataset of TMS/hd-EEG recordings obtained from 108 healthy subjects and 108 brain-injured patients, and tested on sparse intracranial recordings (SEEG) of 9 patients undergoing intracranial single-pulse electrical stimulation (SPES) during wakefulness and sleep. RESULTS: When calculated on TMS/hd-EEG potentials, PCI(ST) performed with the same accuracy as the original PCI, while improving on the previous method by being computed in less than a second and requiring a simpler set-up. In SPES/SEEG signals, the index was able to quantify a systematic reduction of intracranial complexity during sleep, confirming the occurrence of state-dependent changes in the effective connectivity of thalamocortical circuits, as originally assessed through TMS/hd-EEG. CONCLUSIONS: PCI(ST) represents a fundamental advancement towards the implementation of a reliable and fast clinical tool for the bedside assessment of consciousness as well as a general measure to explore the neuronal mechanisms of loss/recovery of brain complexity across scales and models.
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Author, co-author :
Comolatti, Renzo
Pigorini, Andrea
Casarotto, Silvia
Fecchio, Matteo
Faria, Guilherme
Sarasso, Simone
Rosanova, Mario
Gosseries, Olivia  ;  Université de Liège - ULiège > Consciousness-Coma Science Group
Boly, Melanie
BODART, Olivier  ;  Centre Hospitalier Universitaire de Liège - CHU > Département de médecine interne > Service de neurologie
LEDOUX, Didier  ;  Centre Hospitalier Universitaire de Liège - CHU > Autres Services Médicaux > Service des soins intensifs
Brichant, Jean-François ;  Université de Liège - ULiège > Département des sciences cliniques > Anesthésie et réanimation
Nobili, Lino
Laureys, Steven  ;  Université de Liège - ULiège > Consciousness-Coma Science Group
Tononi, Giulio
Massimini, Marcello
Casali, Adenauer G.
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Title :
A fast and general method to empirically estimate the complexity of brain responses to transcranial and intracranial stimulations.
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Journal title :
Brain Stimulation
Publisher :
Elsevier, Netherlands
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Peer reviewed :
Peer Reviewed verified by ORBi
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Copyright (c) 2019 Elsevier Inc. All rights reserved.
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since 22 August 2019


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