Pain Perception in Disorders of Consciousness: Neuroscience, Clinical Care, and Ethics in Dialogue

Demertzi, Athena; Racine, Éric; Bruno, Marie-Aurélie; Ledoux, Didier; Gosseries, Olivia; Vanhaudenhuyse, Audrey; Thonnard, Marie; Soddu, Andrea; Moonen, Gustave; Laureys, Steven

doi:10.1007/s12152-011-9149-x

Cited by 44 publications

(34 citation statements)

References 88 publications

(91 reference statements)

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“…Such advances are naturally accompanied by legitimate neuroscientific and ethical queries, such as on pain perception and management as well as end-oflife options [47][48][49][50]. In the future, efforts should be made towards consciousness classification metrics, where systemlevel functional neuroimaging and electrophysiology will provide an objective means to better characterize the underlying mechanisms accounting for conscious cognition and its recovery after severe acquired brain injury.…”

Section: Discussionmentioning

confidence: 99%

Consciousness supporting networks

Demertzi¹,

Soddu²,

Laureys³

2013

Current Opinion in Neurobiology

172

115

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. Author's personal copy In most cases authors Consciousness supporting networksAthena Demertzi, Andrea Soddu and Steven LaureysFunctional neuroimaging shows that patients with disorders of consciousness exhibit disrupted system-level functional connectivity. Unresponsive/''vegetative state'' patients preserve wakefulness networks of brainstem and basal forebrain but the cerebral networks accounting for external perceptual awareness and internal self-related mentation are disrupted. Specifically, the 'external awareness' network encompassing lateral fronto-temporo-parietal cortices bilaterally, and the 'internal awareness' network including midline anterior cingulate/mesiofrontal and posterior cingulate/ precuneal cortices, are functionally disconnected. By contrast, patients in minimally conscious state 'minus', who show nonreflex behaviors, are characterized by right-lateralized recovery of the external awareness network. Similarly, patients who evolve to minimally conscious state 'plus' and respond to commands recover the dominant left-lateralized language network. Now, the use of active experimental paradigms targeting at detecting motor-independent signs of awareness or even establishing communication with these patients, challenge these two clinical boundaries. Such advances are naturally accompanied by legitimate neuroscientific and ethical queries demanding our attention on the medical implementations of this new knowledge. What is 'minimally conscious'?At present there is no generally accepted definition of consciousness [1]. As clinicians, we will reduce the complexity of this term and define consciousness operationally, separating two main components: wakefulness and awareness [2]. Wakefulness has been shown to critically depend upon the functional integrity of subcortical arousal systems over 50 years ago [(e.g., see 3)]. The level of wakefulness can be estimated by simple behavioral criteria based on eye opening ranging from absent, over stimulus-induced to spontaneous sustained eye opening.For instance, every night when falling asleep, we experience a decrease of the level of wakefulness up to the point we lose awareness of our environment. Awareness is more difficult to define and more challenging to assess behaviorally [4]. We have recently proposed to reduce the phenomenological complexity of awareness into two further components: external awareness, namely everything we perceive through our senses (what we see, hear, feel, smell and taste), and internal awareness or stimulusindependent thoughts. Interestingly, the switch between the external and internal milieu was found not only to characterize overt...

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Section: Discussionmentioning

confidence: 99%

Consciousness supporting networks

Demertzi¹,

Soddu²,

Laureys³

2013

Current Opinion in Neurobiology

172

115

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“…Concern for the patient's suffering and, hence, about the subjective experience of pain, is an ethical responsibility of clinicians and can influence treatment decisions [4]. As mentioned previously, current studies aim to investigate whether those patients are capable of this subjective suffering [22,23,27].…”

Section: Other Approaches Under Development For Assessment Of Nocicepmentioning

confidence: 99%

“…It is impossible for them to express their feelings or even to use any usual scale (such as the Visual Analogue Scale) to communicate the presence of pain and its subjective intensity [3]. This is, however, one of the most important questions to address, as it has obvious clinical and ethical implications [4]. This review will introduce the neuroimaging findings related to pain perception in patients with disorders of consciousness (DOC) as well as the recent and current investigations performed to develop and validate behavioural protocols (such as the Nociception Coma Scale-Revised; NCS-R [5]) which will help clinicians in assessing and treating pain in those patients.…”

Section: Introductionmentioning

confidence: 99%

Pain issues in disorders of consciousness

Chatelle¹,

Thibaut²,

Whyte³

et al. 2014

Brain Injury

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Background: The assessment of pain and nociception in non-communicative patients with disorders of consciousness (DOC) is a real challenge for clinicians. It is, therefore, important to develop sensitive standardized tools usable at the bedside. Objectives: This review aims to provide an overview of the current knowledge about pain processing and assessment in patients with DOC. Methods: A search was performed on PubMed using MeSH terms including vegetative state, unresponsive wakefulness syndrome, minimally conscious state, consciousness disorders, pain, nociception, neuroimaging and pain assessment. Results: Neuroimaging studies investigating pain processing in patients with DOC and their implication for clinicians are reviewed. Current works on the development of standardized and sensitive tools for assessing nociception are described. Conclusion: The suggested pain perception capacity highlighted by neuroimaging studies in patients in a MCS and in some patients in a VS/UWS supports the idea that these patients need analgesic treatment and monitoring. The first tool which has been developed to assess nociception and pain in patients with DOC is the NCS. Its revised version represents a rapid, standardized and sensitive scale which can be easily implemented in a clinical setting. Complementary pain assessments are also under validation in order to offer more options to clinicians.

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“…In these cases, caregivers have to rely on observable signs, such as facial expression. In newborns, for instance, tongue protrusion and licking the lips can be considered a positive affective expression, whereas brow wrinkling and opening the eyes wide are usually considered as facial expressions of negative affect [8]. To achieve a more reliable assessment, several instruments, such as the Visual Analog Scale for pain, are based on these observable signs.…”

Section: Problems With Assessment Of Comfort In Dying Patientsmentioning

confidence: 99%

“…However, this topic is still controversial and poses clinical and ethical challenges [8]. In cases of painful interventions and especially after decisions to withdraw life-sustaining support, such as mechanical ventilation or artificial hydration and nutrition, these patients are, therefore, sometimes left without administration of opioids or other analgesic.…”

Section: Problems With Assessment Of Comfort In Dying Patientsmentioning

confidence: 99%