Pain issues in disorders of consciousness

Abstract

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.

Diagnostic, pronostic et traitements des troubles de la conscience

“…Un seuil de 4 ou plus suggère la présence de douleurs. Une étude utilisant le PET-scan a montré une corrélation positive entre les scores totaux de la NCS-R et le métabolisme cérébral de la partie postérieure du cortex cingulaire antérieur, une région connue pour son implication dans les processus cognitifs et affectifs de la gestion de la douleur [88]. Ces résultats confirment l'hypothèse selon laquelle la NCS-R est liée au traitement cortical de la douleur.…”

Differences That Make a Difference in Disorders of Consciousness

“…Most fundamentally, the intact networks present in MCS point to the potential to perceive pain (Chatelle et al 2014b). This calls for an immediate acknowledgment of the neuro-palliative care needs of members of this population (Fins 2008b;Fins and Pohl 2015;Fins and Master 2017), whose state is often conflated with insensate vegetative patients, often to their peril.…”

Unresponsive, but Aware: The Non-Behavioral Minimally Conscious State

“…Furthermore, patients in MCS appear more responsive to neurostimulant attempts to promote recovery. Indeed, a double-blind sham-controlled study with transcranial direct current stimulation revealed lasting increases of responsiveness in 43% of the patients in MCS, but only 8% of the patients in UWS [8]. Deep brain stimulation with electrode placement in the thalamic intralaminar nuclei also has been shown to induce systematic behavioral improvement in one MCS patient [9].…”