Scottish Centre for Innovation in Spinal Cord Injury

Mechanisms of Neuropathic Pain after Spinal Cord Injury

Pain is a major problem after spinal cord injury, affecting around 50% of patients, with often debilitating consequences. It is not predictable which patients will go on to develop pain, with all different types of injuries being affected. The pain conditions are also often resistant to traditional pain treatment, and there is no alternative effective treatment currently. Therefore, the main aim of this project is to investigate the mechanisms behind neuropathic pain after spinal cord injury. We have a focus on the spinothalamic tract, which is the pathway through which pain is conducted in the spinal cord. To achieve this goal, we are studying both perceptual and brain responses to different kinds of sensory stimuli applied at or below the level of injury.

We are looking at various types of patients, both complete and incomplete (according to their ASIA score), acute (1 month) and chronic (3+ years) patients, and those with and without existing pain problems. There are four visits the participants may be invited to, detailed below. For acute participants we are also interested in following their recovery, monitoring any pain conditions that arise. This will allow us to determine if our tests are a prognostic tool, which will facilitate interventional studies in the future.

Visits

The first visit is to characterise the participant’s injury using the ISNCSCI test, and a small selection of other sensory stimuli. We will also do a pain questionnaire with the participants at this first visit. The main aim of this visit is to understand the injury, where sensation is preserved and lost, where (and if) pain is localised and preliminary investigation of sensory perception across the body.

The second visit is a more in-depth test of sensory function. This visit will use various types of stimuli designed to elicit nociceptive receptors in the skin. The equipment used includes a laser along with a thermal camera, contact thermal device (thermode), weighted pinpricks, von Frey light touch hairs and electrical stimulation equipment. Each of these elicit different sensations when applied to normal areas of sensation and will allow us to determine if any sparing has occurred in the spinothalamic tract.

The third visit is the first measuring brain response to stimuli, using Electroencephalography or EEG. A selection of the stimuli used in visit two will be applied whilst recording EEG from the participant. We will also record some resting state EEG.

The fourth visit is for functional MRI at the ultra-high field 7T MRI located at the Imaging Centre for Excellence (ICE), adjacent to the spinal cord unit. A small selection of suitable participants will be selected for this visit. We will apply heat stimuli using the thermode during this session, whilst recording functional MRI. We will also record a resting state scan, and a high-resolution anatomical scan of the head and brain.

At the follow up visits with the acute participants, we will review their ISNCSCI score, along with a repeat of the pain questionnaire from visit one. This will allow us to track their recovery and pain conditions that develop over time.

Contact for the study is Alison Symon at a.symon.1@research.gla.ac.uk.