Assessment and management of pain/nociception in patients with disorders of consciousness or locked-in syndrome: A narrative review

Abstract

The assessment and management of pain and nociception is very challenging in patients unable to communicate functionally such as patients with disorders of consciousness (DoC) or in locked-in syndrome (LIS). In a clinical setting, the detection of signs of pain and nociception by the medical staff is therefore essential for the wellbeing and management of these patients. However, there is still a lot unknown and a lack of clear guidelines regarding the assessment, management and treatment of pain and nociception in these populations. The purpose of this narrative review is to examine the current knowledge regarding this issue by covering different topics such as: the neurophysiology of pain and nociception (in healthy subjects and patients), the source and impact of nociception and pain in DoC and LIS and, finally, the assessment and treatment of pain and nociception in these populations. In this review we will also give possible research directions that could help to improve the management of this specific population of severely brain damaged patients.

Neuro-orthopaedic assessment and management in patients with prolonged disorders of consciousness: A review

“…Figure 4: Variation in diagnosis of patients with pathological states of consciousness according to the level of recovery of cognitive motor functions. UWS, unresponsive wakefulness syndrome; MCS, minimally conscious state; LIS, locked-in syndrome; in red, patients able to process nociceptive inputs and able to experience pain; in blue, patients processing nociceptive inputs but without evidence of pain experience; in purple, patients able to process nociceptive inputs and having the (probable) neural basis for pain experience (from (Estelle A.C. Bonin et al, 2023b)).…”

Medicolegal issues and disorders of consciousness

“…Clinicians as well as those providing expert witness testimony should be familiar with current definitions within this framework as well as their medicolegal implications. Bonin et al (2023) developed a figure well representing the pathological states of consciousness according to the levels of recovery of cognitive and motor function encompassing current nomenclature of coma, UWS, MCS-, MCS+, MCS*, cognitive motor dissociation, locked-in syndrome (complete) (note: incomplete LIS not listed), emergence from MCS, severe disability, moderate disability and lastly full recovery (Gosseries, Laureys, 2022). Such diagnostic labels can be helpful in terms of educating the triers of fact regarding the claimant's situation neurologically, neuromedically, prognostically and has potential implications on the individual's quality of life; however, they should not be seen as absolutes in terms of defining issues such as quality of life, end-of-life decision making, median survival time, likelihood of pain and suffering among other issues (Katz, Polyak, Coughlan, et al, 2009).…”