Pain and nociception in patients with a disorder of consciousness (DOC)

Pain and nociception in patients with a disorder of consciousness (DOC)

Investigators : Nicolas Lejeune, Steven Laureys, André Mouraux

Management of pain in patients with a disorder of consciousness (DOC) is most probably often inadequate and raises questions about their quality of life. At present, there are no tools to assess pain perception in these patients that do not rely on residual abilities of the patient to exhibit physical signs of pain. The first goal of our project is to develop a non-invasive means to assess the ability of patients with different level of DOC to perceive pain that can be used at bedside and is independent of patient communication skills. The second goal is to examine whether, on average, the ability to process nociceptive information is more resilient to brain damage as compared to the ability to process non-nociceptive ones. The proposed approach is based on electroencephalographic (EEG) recordings of brain responses elicited by stimuli selectively activating (1) heat-sensitive nociceptor, (2) cold receptors and (3) low-threshold mechanoreceptors. Comparison of the elicited responses will allow us to evaluate the ability of the brain to process nociceptive and non-nociceptive stimuli conveyed through the lemniscal and extralemniscal pathways. Analysis of the correlation between these brain responses and stimulus-evoked behavioral and autonomic responses will allow us to identify EEG « biomarkers » for the ability to exhibit pain-related behaviors. Finally, analysis of the relationship between these brain responses and structural and resting state functional magnetic resonance imaging will allow us to examine whether the ability of the brain to respond to nociceptive or non-nociceptive somatosensory stimuli can be related to lesions of specific brain structures or ensembles of brain structures, or to differences in the state of resting state networks. Taken together, our project should provide valuable information to understand the relations between consciousness and pain perception in humans.