The analysis of spontaneous electroencephalogram (EEG) is a cornerstone in the assessment of patients with disorders of consciousness (DoC). Although preserved EEG patterns are highly suggestive of consciousness even in unresponsive patients, moderately or severely abnormal patterns are difficult to interpret. Indeed, growing evidence shows that consciousness can be present despite either large delta or reduced alpha activity in spontaneous EEG. Quantifying the complexity of EEG responses to direct cortical perturbations (perturbational complexity index [PCI]) may complement the observational approach and provide a reliable assessment of consciousness even when spontaneous EEG features are inconclusive. To seek empirical evidence of this hypothesis, we compared PCI with EEG spectral measures in the same population of minimally conscious state (MCS) patients (n = 40) hospitalized in rehabilitation facilities. We found a remarkable variability in spontaneous EEG features across MCS patients as compared with healthy controls: in particular, a pattern of predominant delta and highly reduced alpha power-more often observed in vegetative state/unresponsive wakefulness syndrome (VS/UWS) patients-was found in a non-negligible number of MCS patients. Conversely, PCI values invariably fell above an externally validated empirical cutoff for consciousness in all MCS patients, consistent with the presence of clearly discernible, albeit fleeting, behavioural signs of awareness. These results confirm that, in some MCS patients, spontaneous EEG rhythms may be inconclusive about the actual capacity for consciousness and suggest that a perturbational approach can effectively compensate for this pitfall with practical implications for the individual patient's stratification and tailored rehabilitation.

Dissociations between spontaneous electroencephalographic features and the perturbational complexity index in the minimally conscious state / S. Casarotto, G. Hassan, M. Rosanova, S. Sarasso, C. Derchi, P.D. Trimarchi, A. Viganò, S. Russo, M. Fecchio, G. Devalle, J. Navarro, M. Massimini, A. Comanducci. - In: EUROPEAN JOURNAL OF NEUROSCIENCE. - ISSN 0953-816X. - 59:5(2024 May), pp. 938-947. [Epub ahead of print] [10.1111/ejn.16299]

Dissociations between spontaneous electroencephalographic features and the perturbational complexity index in the minimally conscious state

S. Casarotto
Primo
;
G. Hassan
Secondo
;
M. Rosanova;S. Sarasso;C. Derchi;S. Russo;M. Fecchio;M. Massimini
Penultimo
;
2024

Abstract

The analysis of spontaneous electroencephalogram (EEG) is a cornerstone in the assessment of patients with disorders of consciousness (DoC). Although preserved EEG patterns are highly suggestive of consciousness even in unresponsive patients, moderately or severely abnormal patterns are difficult to interpret. Indeed, growing evidence shows that consciousness can be present despite either large delta or reduced alpha activity in spontaneous EEG. Quantifying the complexity of EEG responses to direct cortical perturbations (perturbational complexity index [PCI]) may complement the observational approach and provide a reliable assessment of consciousness even when spontaneous EEG features are inconclusive. To seek empirical evidence of this hypothesis, we compared PCI with EEG spectral measures in the same population of minimally conscious state (MCS) patients (n = 40) hospitalized in rehabilitation facilities. We found a remarkable variability in spontaneous EEG features across MCS patients as compared with healthy controls: in particular, a pattern of predominant delta and highly reduced alpha power-more often observed in vegetative state/unresponsive wakefulness syndrome (VS/UWS) patients-was found in a non-negligible number of MCS patients. Conversely, PCI values invariably fell above an externally validated empirical cutoff for consciousness in all MCS patients, consistent with the presence of clearly discernible, albeit fleeting, behavioural signs of awareness. These results confirm that, in some MCS patients, spontaneous EEG rhythms may be inconclusive about the actual capacity for consciousness and suggest that a perturbational approach can effectively compensate for this pitfall with practical implications for the individual patient's stratification and tailored rehabilitation.
MCS; PCI; alpha; delta; electroencephalogram;
Settore BIO/09 - Fisiologia
Settore MED/26 - Neurologia
   Dealing with patients with consciousness disorders: a multimodal approach to support the diagnosis and prognosis
   MINISTERO DELLA SALUTE
   GR-2016-02361494

   NEurological MEchanismS of Injury and Sleep-like cellular dynamics (NEMESIS)
   NEMESIS
   EUROPEAN COMMISSION
   101071900

   Human Brain Project Specific Grant Agreement 3 (HBP SGA3)
   HBP SGA3
   EUROPEAN COMMISSION
   H2020
   945539
mag-2024
5-mar-2024
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/1035869
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