Pain-Autonomic Interaction in Neuropathic Pain after Spinal Cord Injury

One of the most commonly encountered complications following spinal cord injury (SCI) is neuropathic pain, a condition that substantially compromises the quality of life for affected individuals. Managing neuropathic pain is challenging due to a lack of understanding of the complex pathophysiological mechanisms that cause and maintain this pain condition. One of the identified key mechanisms is central sensitization which can span along the entire neuroaxis. While subjective, psychophysical assessment tools, e.g. pain questionnaires/drawings and quantitative sensory testing are currently utilized to indirectly evaluate such sensitization processes, more objective, physiological measurements of sensitization are lacking. In this regard, our research group makes use of the fact that the nociceptive and autonomic nervous systems are functionally and structurally closely related and interact in a bidirectional manner. For instance, a noxious stimulus triggers a plethora of autonomic responses such as increases in sympathetic skin responses, blood pressure, heart rate, and pupil dilation. 

Over the past few years, our group has gathered initial evidence that painrelated autonomic measures can indeed serve as surrogate markers for central sensitization in patients with widespread neuropathic pain after SCI. Current ongoing projects seek to explore the relationship between the cardiovascular and pain control systems. Both systems are known to be potentially dysfunctional after an SCI, but their relationship has not been investigated yet and might provide a novel target for pain intervention.