Functional Characterization of At-Level Hypersensitivity in Patients With Spinal Cord Injury

Area of Science:

• Neuroscience
• Pain Research
• Spinal Cord Injury Research

Background:

• Chronic complete thoracic spinal cord injury (SCI) can lead to hypersensitivity.
• Understanding the mechanisms linking SCI-induced hypersensitivity to neuropathic pain is crucial.

Purpose of the Study:

• To investigate at-level and above-level hypersensitivity in chronic complete thoracic SCI patients.
• To determine the relationship between hypersensitivity and neuropathic pain development.

Main Methods:

• Classified SCI patients into groups with (SCIHs) and without (SCINHs) at-level hypersensitivity using somatosensory mapping.
• Utilized quantitative sensory testing (QST), electrical and histamine-induced pain/itch, laser Doppler imaging, and laser-evoked potentials (LEP).

Main Results:

• Six of 8 SCIHs patients reported below-level neuropathic pain, compared to 0 of 7 SCINHs patients.
• Clinical hypersensitivity spread to above-level areas in 3 SCIHs patients.
• No significant difference in electrically evoked pain between SCIHs and SCINHs groups.

Conclusions:

• Clinically assessed at-level hypersensitivity is linked to below-level neuropathic pain, suggesting neuronal hyperexcitability's role.
• SCI-induced enhanced excitability does not invariably result in neuropathic pain.
• QST and LEP suggest deafferentation is not critical for SCI hypersensitivity.