Brain Responses to Propofol in Advance of Recovery from Coma and Disorders of Consciousness: A Preliminary Study

Duclos, Catherine; Maschke, Charlotte; Mahdid, Yacine; Nadin, Danielle; Rokos, Alexander; Arbour, Caroline; Badawy, Mohamed; Létourneau, Justin; Owen, Adrian M.; Plourde, Gilles; Blain-Moraes, Stefanie

doi:10.1164/rccm.202105-1223oc

Cited by 14 publications

(18 citation statements)

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“…Both parameters of the aperiodic component were estimated from 1-45 Hz using the 'Fitting oscillations and one over f' (FOOOF) algorithm (16) (see Methods). Oscillatory power in the delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), beta (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) and gamma (30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45) bandwidth was calculated before and after the removal of the aperiodic component. The detection of oscillatory peak frequency was performed using the FOOOF algorithm.…”

Section: Resultsmentioning

confidence: 99%

Aperiodic brain activity and response to anesthesia vary in disorders of consciousness

Maschke

Duclos²,

Owen

et al. 2022

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In the human electroencephalogram (EEG), oscillatory power peaks co-exist with non-oscillatory, aperiodic activity. Although EEG analysis has traditionally focused exclusively on oscillatory power, recent investigations have shown that the aperiodic EEG component can distinguish conscious wakefulness from sleep and anesthetic-induced unconsciousness (Lendner et al. 2020). This study investigates the aperiodic EEG component of individuals in a disorder of consciousness (DOC), and how it changes in response to exposure to anesthesia. High-density EEG was recorded from 43 individuals in a DOC. To measure the brain’s reaction to global perturbation, a subset of n = 16 were also exposed to a targeted infusion of propofol anesthesia. The aperiodic component was defined by the spectral slope and offset in the 1-45 Hz and 30-45 Hz range of the power spectral density. Brain network criticality and complexity were estimated using the pair correlation function (PCF) and Lempel-Ziv complexity, respectively. The level of responsiveness of all individuals in DOC was assessed using the Coma Recovery Scale-Revised (CRS-R). Recovery of consciousness was assessed three months post-EEG. At baseline, the EEG aperiodic component was more strongly correlated to the participants’ level of consciousness than the oscillatory component. Anesthesia caused a steepening of the spectral slope across participants. Importantly, the change in spectral slope positively correlated with the individual participant’s level of responsiveness. The spectral slope during exposure to anesthesia contained prognostic value for individuals with DOC. The anesthetic-induced change in aperiodic EEG was accompanied by loss of information-richness and a reduction in network criticality. The aperiodic EEG component in individuals with DOC has been historically neglected; this research highlights the importance of considering this measure for future research investigating brain mechanisms underlying consciousness.Significance StatementThe analysis of human EEG has traditionally focused on oscillatory power, which is characterized by peaks above a broadband, aperiodic component in the EEG power spectral density. This study is the first to demonstrate the value of the aperiodic EEG component and specifically, its reaction to propofol anesthesia for assessing individual’s level of, and capacity for, consciousness. Our results demonstrates that the pharmacological induced change in the aperiodic component accompanies the brain’s loss of network criticality and complexity. Most importantly, the magnitude of brain response to propofol anesthesia relies on an individual’s pre-anesthetic level of consciousness. Whereas the aperiodic EEG component has been historically neglected; this research highlights the necessity of considering this measure for future research that seeks to understand the neurophysiological underpinnings of consciousness.

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Section: Resultsmentioning

confidence: 99%

Aperiodic brain activity and response to anesthesia vary in disorders of consciousness

Maschke

Duclos²,

Owen

et al. 2022

Preprint

Self Cite

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“…In this issue of the Journal , Duclos and colleagues (pp. 171–182 ) present results from a small clinical study in which they administer propofol to 12 patients who are in a minimally conscious state or who have unresponsive wakefulness syndrome, previously referred to as a persistent vegetative state ( 5 ). The idea behind this study is that the function and integrity of certain brain networks can be inferred by analyzing data from a combination of electroencephalographic channels.…”

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confidence: 99%

“…The authors leverage this concept, which has been demonstrated in both awake individuals performing a task and in the spontaneous activity of the anesthetized brain. They propose the adaptive reconfiguration index as a surrogate for network resilience; when there is little change in network configuration on exposure to propofol, the index is low, and when brain networks respond like that of a healthy individual, the index is high ( 5 ). Interestingly, three patients who had high adaptive reconfiguration indices in response to propofol all fully regained consciousness within three months.…”

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confidence: 99%

“…None of the patients with low adaptive reconfiguration indices regained consciousness. The intriguing hypothesis emerges that the combination of propofol with a readily derived, standard 18-channel–based electroencephalographic index can be used as a pragmatic, bedside prognosticator in the ICU for patients in a minimally conscious state ( 5 ).…”

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confidence: 99%

“…Duclos and colleagues have now addressed this question in a larger patient cohort, demonstrating the further promise of using propofol to probe the response and resiliency of brain networks in patients with pathological states of unconsciousness ( 5 ). Although the adaptive reconfiguration index was 100% accurate in this study in predicting the return of full consciousness within three months, this finding should still be regarded as preliminary because only 3 of 12 patients regained full consciousness in the time frame of interest ( 5 ).…”

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