Combined behavioral and electrophysiological evidence for a direct cortical effect of prefrontal tDCS on disorders of consciousness

Hermann, Bertrand; Raimondo, Federico; Hirsch, Lukas; Huang, Yu; Denis-Valente, Mélanie; Pérez, Pauline; Engemann, Denis A.; Faugeras, Frédéric; Weiss, Nicolas; Demeret, Sophie; Rohaut, Benjamin; Parra, Lucas C.; Sitt, Jacobo; Naccache, Lionel

doi:10.1101/612309

Cited by 5 publications

(4 citation statements)

References 75 publications

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“…In Fig. 5D we showed that transitions towards states of heightened consciousness were systematically linked to perturbations located in the precuneus, temporo-parietal junction and the middle frontal cortex, regions presenting a significant overlap with the default mode network (65) and in line with electrical stimulation targets shown to improve behavioural signatures of consciousness in DoC patients (38). These regions have also been shown to robustly reflect the level of consciousness (46,55,66,67) and conscious information access in cognitive neuroscience paradigms (1).…”

Section: Discussionmentioning

confidence: 86%

Perturbations in dynamical models of whole-brain activity dissociate between the level and stability of consciousness

Perl

Pallavicini

Ipiña

et al. 2020

Preprint

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AbstractConsciousness transiently fades away during deep sleep, more stably under anesthesia, and sometimes permanently due to brain injury. The development of an index to quantify the level of consciousness across these different states is regarded as a key problem both in basic and clinical neuroscience. We argue that this problem is ill-defined since such an index would not exhaust all the relevant information about a given state of consciousness. While the level of consciousness can be taken to describe the actual brain state, a complete characterization should also include its potential behavior against external perturbations. We developed and analyzed whole-brain computational models to show that the stability of conscious states provides information complementary to their similarity to conscious wakefulness. Our work leads to a novel methodological framework to sort out different brain states by their stability and reversibility, and illustrates its usefulness to dissociate between physiological (sleep), pathological (brain-injured patients), and pharmacologically-induced (anesthesia) loss of consciousness.

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Section: Discussionmentioning

confidence: 86%

Perturbations in dynamical models of whole-brain activity dissociate between the level and stability of consciousness

Perl

Pallavicini

Ipiña

et al. 2020

Preprint

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“…This physiological heterogeneity may also explain the inter-subject variability in response to certain treatments. As such, recent studies demonstrated a correlation between the therapeutic efficacy of transcranial direct current stimulation, and the subjects underlying brain anatomy and metabolism (Thibaut et al ., 2015, 2018; Hermann et al ., 2019). More developed neuroimaging techniques could both help to better stratify patients for therapeutic intervention, and to develop tailored treatment strategies, which are still desperately needed for these debilitating conditions.…”

Section: Discussionmentioning

confidence: 99%

Multimodal FDG-PET and EEG assessment improves diagnosis and prognostication of disorders of consciousness

Hermann

Stender

Habert

et al. 2020

Preprint

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The complex diagnosis of disorders of consciousness (DoC) diagnosis increasingly relies on brain-imaging techniques for their ability to detect residual signs of consciousness in otherwise unresponsive patients. However, few of these techniques have been validated on external datasets. Here, we show that the FDG-PET glucose metabolic index of the best preserved hemisphere has robust in-sample and out-sample performances to diagnose DoC, slightly outperforming EEG-based classification. We further show that a multimodal assessment combining both FDG-PET and EEG not only improved diagnostic performances, but also allowed to identify covert cognition and to predict 6-month responsiveness in initially unresponsive patients. Lastly, we show that DoC heterogeneity reflects a sum of regional cortical metabolic differences, and their corresponding behavioral patterns, rather than a binary contrast between conscious and unconscious states. In total, we show that FDG-PET and EEG provide complementary information on DoC physiopathology and that their combination improves DoC diagnosis and prognostication.

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“…Neurostimulation has specific ethical implications for patients unable to communicate pain. Clinical effects of neuromodulation in adults with DoC are promising but heterogeneous (~40% of adults in MCS and ~10% in a vs. improved signs of consciousness [ 77 , 78 , 89 , 90 , 91 , 92 ] with transcranial direct current stimulation; safety in children is still under investigation [ 93 ]). Overall, a one-size-fits-all treatment is unlikely, and we envisage that well-defined coma endotypes will receive tailored treatments in the future.…”

Section: Medical Technologies For Treatmentmentioning

confidence: 99%

Emerging Treatments for Disorders of Consciousness in Paediatric Age

et al. 2022

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The number of paediatric patients living with a prolonged Disorder of Consciousness (DoC) is growing in high-income countries, thanks to substantial improvement in intensive care. Life expectancy is extending due to the clinical and nursing management achievements of chronic phase needs, including infections. However, long-known pharmacological therapies such as amantadine and zolpidem, as well as novel instrumental approaches using direct current stimulation and, more recently, stem cell transplantation, are applied in the absence of large paediatric clinical trials and rigorous age-balanced and dose-escalated validations. With evidence building up mainly through case reports and observational studies, there is a need for well-designed paediatric clinical trials and specific research on 0–4-year-old children. At such an early age, assessing residual and recovered abilities is most challenging due to the early developmental stage, incompletely learnt motor and cognitive skills, and unreliable communication; treatment options are also less explored in early age. In middle-income countries, the lack of rehabilitation services and professionals focusing on paediatric age hampers the overall good assistance provision. Young and fast-evolving health insurance systems prevent universal access to chronic care in some countries. In low-income countries, rescue networks are often inadequate, and there is a lack of specialised and intensive care, difficulty in providing specific pharmaceuticals, and lower compliance to intensive care hygiene standards. Despite this, paediatric cases with DoC are reported, albeit in fewer numbers than in countries with better-resourced healthcare systems. For patients with a poor prospect of recovery, withdrawal of care is inhomogeneous across countries and still heavily conditioned by treatment costs as well as ethical and cultural factors, rather than reliant on protocols for assessment and standardised treatments. In summary, there is a strong call for multicentric, international, and global health initiatives on DoC to devote resources to the paediatric age, as there is now scope for funders to invest in themes specific to DoC affecting the early years of the life course.

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Combined behavioral and electrophysiological evidence for a direct cortical effect of prefrontal tDCS on disorders of consciousness

Cited by 5 publications

References 75 publications

Perturbations in dynamical models of whole-brain activity dissociate between the level and stability of consciousness

Perturbations in dynamical models of whole-brain activity dissociate between the level and stability of consciousness

Multimodal FDG-PET and EEG assessment improves diagnosis and prognostication of disorders of consciousness

Emerging Treatments for Disorders of Consciousness in Paediatric Age

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