Publications of Olivier BODART
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See detailSimplified Evaluation of CONsciousness Disorders (SECONDs) in individuals with severe brain injury: A validation study
Aubinet, Charlène ULiege; Cassol, Helena ULiege; BODART, Olivier ULiege et al

in Annals of Physical and Rehabilitation Medicine (2021), 64(5), 101432

Background The Coma Recovery Scale-Revised (CRS-R) is the gold standard to assess severely brain-injured patients with prolonged disorders of consciousness (DoC). However, the amount of time needed to ... [more ▼]

Background The Coma Recovery Scale-Revised (CRS-R) is the gold standard to assess severely brain-injured patients with prolonged disorders of consciousness (DoC). However, the amount of time needed to complete this examination may limit its use in clinical settings. Objective. We aimed to validate a new faster tool to assess consciousness in individuals with DoC. Methods This prospective validation study introduces the Simplified Evaluation of CONsciousness Disorders (SECONDs), a tool composed of 8 items: arousal, localization to pain, visual fixation, visual pursuit, oriented behaviors, command-following, and communication (both intentional and functional). A total of 57 individuals with DoC were assessed on 2 consecutive days by 3 blinded examiners: one CRS-R and one SECONDs were performed on 1 day, whereas 2 SECONDs were performed on the other day. A Mann-Whitney U test was used to compare the duration of administration of the SECONDs versus the CRS-R, and weighted Fleiss’ kappa coefficients were used to assess inter-/intra-rater reliability as well as concurrent validity. Results In the 57 participants, the SECONDs was about 2.5 times faster to administer than the CRS-R. The comparison of the CRS-R versus the SECONDs on the same day or the best of the 3 SECONDs led to “substantial” or “almost perfect” agreement (kappa coefficients ranging from 0.78 to 0.85). Intra-/inter-rater reliability also showed almost perfect agreement (kappa coefficients from 0.85 to 0.91 and 0.82 to 0.85, respectively). Conclusions The SECONDs appears to be a fast, reliable and easy-to-use scale to diagnose DoC and may be a good alternative to other scales in clinical settings where time constraints preclude a more thorough assessment. [less ▲]

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See detailEvaluation of the effect of analgesic treatment on signs of nociception-related behaviors during physiotherapy in patients with disorders of consciousness: a pilot crossover randomized controlled trial
Bonin, Estelle ULiege; Binda Fossati, Mariachiara Luisella ULiege; Filippini, Maddalena et al

in Pain (2021)

Neuro-orthopedic disorders are common in patients with disorders of consciousness (DOC) and can lead to potential pain. However, the patients' inability to communicate makes pain detection and management ... [more ▼]

Neuro-orthopedic disorders are common in patients with disorders of consciousness (DOC) and can lead to potential pain. However, the patients' inability to communicate makes pain detection and management very challenging for clinicians. In this crossover randomized double-blind placebo-controlled study, we investigated the effects of an analgesic treatment on the presence of nociception-related behaviors. At baseline, the Nociception Coma Scale-Revised (NCS-R) was performed in 3 conditions: a non-noxious stimulation, a noxious stimulation, and during a physiotherapy session. Patients with a NCS-R total score during physiotherapy equal or above the score observed after the noxious stimulation could participate to the clinical trial, as well as patients with a score above 5. They received an analgesic treatment and a placebo on 2 consecutive days in a randomized order followed by an assessment with the NCS-R. Of the 18 patients, 15 displayed signs of potential pain during physiotherapy. Patients showed higher NCS-R scores during physiotherapy compared with the other conditions, suggesting that mobilizations were potentially painful. Of these 15 patients, 10 met the criteria to participate in the placebo-controlled trial. We did not find any effect of analgesic treatment on the NCS-R scores. This study highlights that physiotherapy may be potentially painful for patients with DOC, while analgesic treatments did not reduced NCS-R scores. Therefore, careful monitoring with appropriate assessment and treatment before and during mobilization should become a priority in clinical settings. Future studies should focus on the development of assessment tools sensitive to analgesic dosage to manage pain in DOC. [less ▲]

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See detailSECONDs administration guidelines: A fast tool for assessing consciousness in brain-injured patients
Sanz, Leandro ULiege; Aubinet, Charlène ULiege; Cassol, Helena ULiege et al

in Journal of Visualized Experiments (2021), (168), 61968

Establishing an accurate diagnosis is crucial for patients with disorders of consciousness (DoC) following a severe brain injury. The Coma Recovery Scale-Revised (CRS-R) is the recommended behavioral ... [more ▼]

Establishing an accurate diagnosis is crucial for patients with disorders of consciousness (DoC) following a severe brain injury. The Coma Recovery Scale-Revised (CRS-R) is the recommended behavioral scale for assessing the level of consciousness among these patients, but its long administration duration is a major hurdle in clinical settings. The Simplified Evaluation of CONsciousness Disorders (SECONDs) is a shorter scale that was developed to tackle this issue. It consists of six mandatory items, observation, command-following, visual pursuit, visual fixation, oriented behaviors, and arousal, and two conditional items, communication and localization to pain. The score ranges between 0 and 8 and corresponds to a specific diagnosis (i.e., coma, unresponsive wakefulness syndrome, minimally conscious state minus/plus, or emergence from the minimally conscious state). A first validation study on patients with prolonged DoC showed high concurrent validity and intra- and inter-rater reliability. The SECONDs requires less training than the CRS-R and its administration lasts about 7 minutes (interquartile range: 5-9 minutes). An additional index score allows the more precise tracking of a patient’s behavioral fluctuation or evolution over time. The SECONDs is therefore a fast and valid tool for assessing the level of consciousness in patients with severe brain injury. It can easily be used by healthcare staff and implemented in time-constrained clinical settings, such as intensive care units, to help decrease misdiagnosis rates and to optimize treatment decisions. These administration guidelines provide detailed instructions for administering the SECONDs in a standardized and reproducible manner, which is an essential requirement for achieving a reliable diagnosis. [less ▲]

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See detailDecreased evoked slow-activity after tDCS in disorders of consciousness
Mensen, Armand; BODART, Olivier ULiege; Thibaut, Aurore ULiege et al

in Frontiers in Systems Neuroscience (2020), 14(62),

Due to life-saving medical advances, the diagnosis and treatment of disorders of consciousness (DOC) has become a more commonly occurring clinical issue. One recently developed intervention option has ... [more ▼]

Due to life-saving medical advances, the diagnosis and treatment of disorders of consciousness (DOC) has become a more commonly occurring clinical issue. One recently developed intervention option has been non-invasive transcranial direct current stimulation. This dichotomy of patient responders may be better understood by investigating the mechanism behind the transcranial direct current stimulation (tDCS) intervention. The combination of transcranial magnetic stimulation and electroencephalography (TMS-EEG) has been an important diagnostic tool in DOC patients. We therefore examined the neural response using TMS-EEG both before and after tDCS in seven DOC patients (four diagnosed as in a minimally conscious state and three with unresponsive wakefulness syndrome). tDCS was applied over the dorsolateral prefrontal cortex, while TMS pulses were applied to the premotor cortex. None of the seven patients showed relevant behavioral change after tDCS. We did, however, find that the overall evoked slow activity was reduced following tDCS intervention. We also found a positive correlation between the strength of the slow activity and the amount of high-frequency suppression. However, there was no significant pre-post tDCS difference in high frequencies. In the resting-state EEG, we observed that both the incidence of slow waves and the positive slope of the wave were affected by tDCS. Taken together, these results suggest that the tDCS intervention can reduce the slow-wave activity component of bistability, but this may not directly affect high-frequency activity. We hypothesize that while reduced slow activity may be necessary for the recovery of neural function, especially consciousness, this alone is insufficient. [less ▲]

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See detailValidation of the SECONDs: a new short scale to assess disorders of consciousness
Aubinet, Charlène ULiege; Cassol, Helena ULiege; BODART, Olivier ULiege et al

Conference (2020, May)

Introduction: Clinical examination of severely brain-injured patients with disorders of consciousness (DoC) requires repeated standardized assessments to provide an accurate diagnosis. However, the ... [more ▼]

Introduction: Clinical examination of severely brain-injured patients with disorders of consciousness (DoC) requires repeated standardized assessments to provide an accurate diagnosis. However, the administration time of the current gold-standard Coma Recovery Scale-Revised (CRS-R) limits its use in clinical routine. We here propose and validate a faster tool to assess consciousness. Methods: The Simplified Evaluation of CONsciousness Disorders (SECONDs) is based on six mandatory items (observation, response to command, visual fixation, visual pursuit, oriented behaviours, arousal) and two conditional items (localisation to pain, communication) (Figure 1). Fifty-seven DoC patients were assessed four times on two consecutive days: one CRS-R and one SECONDs were administered on one day, whereas two SECONDs were administered on the other day (Figure 2). The three examiners remained blind to diagnosis and medical history of the patients. Concurrent validity and inter-/intra-rater reliability were computed using weighted kappa coefficients, while administration times for the SECONDs vs. the CRS-R were compared with a Mann-Whitney U test. Results: “Substantial” and “almost perfect” agreements (kappas: 0.78-0.85) were found comparing the CRS-R against the same-day SECONDs or against the highest-scoring SECONDs. Intra- and inter-rater reliabilities showed “almost perfect” agreements (kappas: 0.85-0.91 and 0.82-0.85 respectively) (Figure 3). Administration time was significantly shorter for the SECONDs than for the CRS-R (7 vs. 17 min, p<0.001). Conclusion: The SECONDs is a fast and valid clinical scale to evaluate patients with DoC. This new tool offers an alternative to existing scales, well-suited for clinicians with major time constraints, and can be easily repeated to provide an accurate diagnosis. [less ▲]

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See detailPrevalence of signs of nociception during physiotherapy in patient with disorders of consciousness.
Bonin, Estelle ULiege; Binda Fossati, Mariachiara Luisella ULiege; Filippini, Maria Maddalena et al

Conference (2020, March 05)

Patients with disorders of consciousness (DOC) may suffer from neuro-orthopaedics disorders that can lead to potential pain during physiotherapy (PT). These patients are unable to communicate it is ... [more ▼]

Patients with disorders of consciousness (DOC) may suffer from neuro-orthopaedics disorders that can lead to potential pain during physiotherapy (PT). These patients are unable to communicate it is therefore a real challenge for clinicians to assess pain and adapt treatment. This randomized double-blind placebo-controlled study aimed to investigate the prevalence of signs of nociception during PT and their changes in relation to a pain-killer. During baseline (D0), pain responsiveness was assessed using the NCS-R (Nociception Coma Scale-Revised): at rest; during a tactile stimulation (TS); during a nociceptive stimulation (NS); and during PT. Then, patient with signs of potential pain during PT was assessed during a placebo and a pain-killer condition (D1 and D2). Our results show that most DOC patients present signs of potential pain during PT (14/19; 73.4%), and a few of them already received analgesic treatment before the study (5/14, 35.7%). During baseline, we found significant differences between the NCS-R score during PT than the three others stimulation, suggesting that passive mobilizations are potentially painful for DOC patient. These difference remains during placebo and treatment condition expect with the NS. We do not found an effect of pain-killer on the NCS-R score during PT and NS. This could be explained by the fact that the NCS-R failed to detect the effect of pain-killer or that this effect was not strong enough. This study point-out that PT may be painful for DOC patients and appropriate assessment and treatment before and during mobilizations should become a priority in clinical setting. [less ▲]

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See detailGeneral Anesthesia: A Probe to Explore Consciousness
BONHOMME, Vincent ULiege; STAQUET, Cécile ULiege; Montupil, Javier ULiege et al

in Frontiers in Systems Neuroscience (2019)

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See detail2 EEG-based methods for the diagnosis of disorders of consciousness
Sanz, Leandro ULiege; Wolff, Audrey ULiege; Fecchio, Matteo et al

Poster (2019, May 17)

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See detailA 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

in Brain Stimulation (2019), 12(5), 1280-1289

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 ... [more ▼]

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. [less ▲]

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See detailEvaluation of the effect of TDCS on TMS-EEG responses in patients with disorders of consciousness
Mensen, Armand ULiege; BODART, Olivier ULiege; Thibaut, Aurore ULiege et al

in Frontiers in Neuroscience (2018, June 21)

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See detailPCI & Auditory ERPs for the diagnosis of disorders of consciousness: a EEG-based methods comparison study
Blandiaux, Séverine ULiege; Raimondo, Federico ULiege; Wolff, Audrey ULiege et al

Conference (2018, June 15)

INTRODUCTION Diagnosing the level of consciousness in patients suffering from severe brain lesions is still a major challenge. EEG-based systems can help discriminate conscious from unconscious patients ... [more ▼]

INTRODUCTION Diagnosing the level of consciousness in patients suffering from severe brain lesions is still a major challenge. EEG-based systems can help discriminate conscious from unconscious patients. This study aims to confront the results from two of the most reliable methods: the Perturbational Complexity Index (PCI) which is based on Transcranial Magnetic Stimulation (TMS-EEG), and a recent machine learning approach using EEG-extracted markers from a standardized oddball auditory stimulation paradigm (EEG-ERP). METHODS Patients presenting either an unresponsive wakefulness syndrome (UWS), a minimally conscious state (MCS) or an emergence of MCS (EMCS) underwent both TMS-EEG and EEG-ERP. We computed PCI value by compressing the spatiotemporal pattern of cortical responses to the perturbation of the cortex with TMS. For EEG-ERP, we extracted 60 markers corresponding to quantification of power spectrum and complexity in individual EEG sensors and information sharing between them. Using machine-learning, we predicted the individual probability of being (minimally) conscious. RESULTS PCI and EEG markers, when considered categorically (i.e. UWS vs MCS), were consistent for all UWS and EMCS patients, whereas the results for MCS patients showed less consistency. Nevertheless, we found a significant correlation between PCI values and the probability of being conscious with the multivariate classifier. CONCLUSION PCI correlated positively with the combination of EEG markers in severely brain-injured patients. These findings imply that EEG signatures of consciousness can be reliably extracted from different contexts and combined into coherent predictive models, encouraging future efforts in large-scale data-driven clinical neuroscience. [less ▲]

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See detailGlobal structural integrity and effective connectivity in patients with disorders of consciousness
BODART, Olivier ULiege; Amico, Enrico; Gomez, Francisco et al

in Brain Stimulation (2018)

Background Previous studies have separately reported impaired functional, structural, and effective connectivity in patients with disorders of consciousness (DOC). The perturbational complexity index (PCI ... [more ▼]

Background Previous studies have separately reported impaired functional, structural, and effective connectivity in patients with disorders of consciousness (DOC). The perturbational complexity index (PCI) is a transcranial magnetic stimulation (TMS) derived marker of effective connectivity. The global fractional anisotropy (FA) is a marker of structural integrity. Little is known about how these parameters are related to each other. Objective We aimed at testing the relationship between structural integrity and effective connectivity. Methods We assessed 23 patients with severe brain injury more than 4 weeks post-onset, leading to DOC or locked-in syndrome, and 14 healthy subjects. We calculated PCI using repeated single pulse TMS coupled with high-density electroencephalography, and used it as a surrogate of effective connectivity. Structural integrity was measured using the global FA, derived from diffusion weighted imaging. We used linear regression modelling to test our hypothesis, and computed the correlation between PCI and FA in different groups. Results Global FA could predict 74% of PCI variance in the whole sample and 56% in the patients' group. No other predictors (age, gender, time since onset, behavioural score) improved the models. FA and PCI were correlated in the whole population (r = 0.86, p < 0.0001), the patients, and the healthy subjects subgroups. Conclusion We here demonstrated that effective connectivity correlates with structural integrity in brain-injured patients. Increased structural damage level decreases effective connectivity, which could prevent the emergence of consciousness. [less ▲]

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