Assessing pain in patients with chronic disorders of consciousness: Are we heading in the right direction?

ERP indicators of situational empathy pain

This study aimed to validate a recent conceptualization proposed by Coll and colleagues (2017a) that defines empathic response as a situational, cognitively complex process requiring emotion identification and affective sharing. Sixty right-handed women university students (18-29 years) voluntarily participated in the study. We measured ratings for empathy pain to assess the individual differences in empathy. At the same time, we collected peak amplitudes of the event-related potentials (ERPs) components to empathic stimulations of painful faces or hand stimuli and neutral images. Electrophysiological results proved that the P2, N170, N2, and P3 ERP components were associated with the modulation of empathic responses. Participants with low empathic responses (p < 0.05) disclosed a larger frontal central N2 for the painful hands than for painful faces (p < .05) and a reduced temporoparietal N170 for painful hands compared to neutral ones. Furthermore, our results highlighted higher frontal central P3a and P3b to painful stimuli than controls (p ≤ 0.01). We explained these findings assuming that in identifying the emotional value of a stimulus, the emotional content can modulate the reorientation of attention and the in-memory updating process associated with the empathic response. Results are in line with Coll and colleagues' conceptualization of the empathic response that includes two cognitive processes, the identification of emotions, and affective sharing, related to the recognition of the emotional state of the other in the self.

Analgesia in the Neurosurgical Intensive Care Unit

Acute pain in neurosurgical patients is an important issue. Opioids are the most used for pain treatment in the neurosurgical ICU. Potential side effects of opioid use such as oversedation, respiratory depression, hypercapnia, worsening intracranial pressure, nausea, and vomiting may be problems and could interfere with neurologic assessment. Consequently, reducing opioids and use of non-opioid analgesics and adjuvants (N-methyl-D-aspartate antagonists, α2 -adrenergic agonists, anticonvulsants, corticosteroids), as well as non-pharmacological therapies were introduced as a part of a multimodal regimen. Local and regional anesthesia is effective in opioid reduction during the early postoperative period. Among non-opioid agents, acetaminophen and non-steroidal anti-inflammatory drugs are used frequently. Adverse events associated with opioid use in neurosurgical patients are discussed. Larger controlled studies are needed to find optimal pain management tailored to neurologically impaired neurosurgical patients.

ERP Indicators of Self-Pain and Other Pain Reductions due to Placebo Analgesia Responding: The Moderating Role of the Fight-Flight-Freeze System

This study evaluates the modulation of phasic pain and empathy for pain induced by placebo analgesia during pain and empathy for pain tasks. Because pain can be conceptualized as a dangerous stimulus that generates avoidance, we evaluated how approach and avoidance personality traits modulate pain and empathy for pain responses. We induced placebo analgesia to test whether this also reduces self-pain and other pain. Amplitude measures of the N1, P2, and P3 ERPs components, elicited by electric stimulations, were obtained during a painful control, as well as during a placebo treatment expected to induce placebo analgesia. The placebo treatment produced a reduction in pain and unpleasantness perceived, whereas we observed a decrease in the empathy unpleasantness alone during the empathy pain condition. The moderator effects of the fight-flight-freeze system (FFFS) in the relationships linking P2 and P3 amplitude changes with pain reduction were both significant among low to moderate FFFS values. These observations are consistent with the idea that lower FFFS (active avoidance) scores can predict placebo-induced pain reduction. Finally, in line with the revised Reinforcement Sensitivity Theory (r-RST), we can assume that phasic pain is an aversive stimulus activating the active-avoidance behavior to bring the system back to homeostasis.

Pain Perception in Disorder of Consciousness: A Scoping Review on Current Knowledge, Clinical Applications, and Future Perspective

Pain perception in individuals with prolonged disorders of consciousness (PDOC) is still a matter of debate. Advanced neuroimaging studies suggest some cortical activations even in patients with unresponsive wakefulness syndrome (UWS) compared to those with a minimally conscious state (MCS). Therefore, pain perception has to be considered even in individuals with UWS. However, advanced neuroimaging assessment can be challenging to conduct, and its findings are sometimes difficult to be interpreted. Conversely, multichannel electroencephalography (EEG) and laser-evoked potentials (LEPs) can be carried out quickly and are more adaptable to the clinical needs. In this scoping review, we dealt with the neurophysiological basis underpinning pain in PDOC, pointing out how pain perception assessment in these individuals might help in reducing the misdiagnosis rate. The available literature data suggest that patients with UWS show a more severe functional connectivity breakdown among the pain-related brain areas compared to individuals in MCS, pointing out that pain perception increases with the level of consciousness. However, there are noteworthy exceptions, because some UWS patients show pain-related cortical activations that partially overlap those observed in MCS individuals. This suggests that some patients with UWS may have residual brain functional connectivity supporting the somatosensory, affective, and cognitive aspects of pain processing (i.e., a conscious experience of the unpleasantness of pain), rather than only being able to show autonomic responses to potentially harmful stimuli. Therefore, the significance of the neurophysiological approach to pain perception in PDOC seems to be clear, and despite some methodological caveats (including intensity of stimulation, multimodal paradigms, and active vs. passive stimulation protocols), remain to be solved. To summarize, an accurate clinical and neurophysiological assessment should always be performed for a better understanding of pain perception neurophysiological underpinnings, a more precise differential diagnosis at the level of individual cases as well as group comparisons, and patient-tailored management.

Uncertain is worse: modulation of anxiety on pain anticipation by intensity uncertainty: evidence from the ERP study

To investigate the effect of uncertain information in the anticipation phase, this study used four cues to inform participants that they would face four kinds of subsequent electrical shocks: low-intensity shock, high-intensity shock, 50-50% chance of low-intensity or high-intensity shock, and no shock. Subjective evaluation on the anxiety elicited by different cues showed that uncertain cues aroused higher anxiety than certain cues, but the effect was observed only at low-intensity shock. The electroencephalogram data revealed that uncertain-shock cue elicited significantly larger stimulus-preceding negativity than certain-high-shock cue at the frontal site. The uncertain-shock cue and certain-high-shock cue both elicited significantly larger stimulus-preceding negativity than the cues of certain-low-shock and nonshock, respectively. Uncertain cues elicited significantly larger pain-evoked P2 than certain cues. The results implied that uncertainty of information regarding shock intensity captured more motivational engagement, aroused higher anxiety on anticipating for the electrical shock, and elicited higher perceived pain of shock stimulation.

Ethical, Palliative, and Policy Considerations in Disorders of Consciousness

This essay complements the scientific and practice scope of the American Academy of Neurology Guideline on Disorders of Consciousness by providing a discussion of the ethical, palliative, and policy aspects of the management of this group of patients. We endorse the renaming of "permanent" vegetative state to "chronic" vegetative state given the increased frequency of reports of late improvements but suggest that further refinement of this class of patients is necessary to distinguish late recoveries from patients who were misdiagnosed or in cognitive-motor dissociation. Additional nosologic clarity and prognostic refinement is necessary to preclude overestimation of low probability events. We argue that the new descriptor "unaware wakefulness syndrome" is no clearer than "vegetative state" in expressing the mismatch between apparent behavioral unawareness when patients have covert consciousness or cognitive motor dissociation. We advocate routine universal pain precautions as an important element of neuropalliative care for these patients given the risk of covert consciousness. In medical decision-making, we endorse the use of advance directives and the importance of clear and understandable communication with surrogates. We show the value of incorporating a learning health care system so as to promote therapeutic innovation. We support the Guideline's high standard for rehabilitation for these patients but note that those systems of care are neither widely available nor affordable. Finally, we applaud the Guideline authors for this outstanding exemplar of engaged scholarship in the service of a frequently neglected group of brain-injured patients.

Ethical, palliative, and policy considerations in disorders of consciousness

This essay complements the scientific and practice scope of the American Academy of Neurology Guideline on Disorders of Consciousness by providing a discussion of the ethical, palliative, and policy aspects of the management of this group of patients. We endorse the renaming of "permanent" vegetative state to "chronic" vegetative state given the increased frequency of reports of late improvements but suggest that further refinement of this class of patients is necessary to distinguish late recoveries from patients who were misdiagnosed or in cognitive-motor dissociation. Additional nosologic clarity and prognostic refinement is necessary to preclude overestimation of low probability events. We argue that the new descriptor "unaware wakefulness syndrome" is no clearer than "vegetative state" in expressing the mismatch between apparent behavioral unawareness when patients have covert consciousness or cognitive motor dissociation. We advocate routine universal pain precautions as an important element of neuropalliative care for these patients given the risk of covert consciousness. In medical decision-making, we endorse the use of advance directives and the importance of clear and understandable communication with surrogates. We show the value of incorporating a learning health care system so as to promote therapeutic innovation. We support the Guideline's high standard for rehabilitation for these patients but note that those systems of care are neither widely available nor affordable. Finally, we applaud the Guideline authors for this outstanding exemplar of engaged scholarship in the service of a frequently neglected group of brain-injured patients.

Rights language and disorders of consciousness: a call for advocacy

Drawing upon sources in neuroethics, civil rights, and disability rights law, we argue for the reintegration of people with severe brain injury back into the nexus of their families and communities consistent with the Americans with Disabilities Act (ADA) and the UN Convention on the Rights of Persons with Disabilities, both of which call for the maximal integration of people with disability into society. To this end, we offer a rights-based argument to address the care of people with severe brain injury. Instead of viewing the provision of rehabilitation as a reimbursement issue, which it surely is, we argue that it can be productively understood as a question of civil rights for a population generally segregated from the medical mainstream and from society itself. Their segregation in the chronic care sector constitutes disrespect for persons, made all the more consequential because recent advances in brain injury rehabilitation make reintegration into civil society an aspirational, if not achievable goal.