Stress-related white matter microstructure alterations and chronic pain

Area of Science:

• Neuroimaging
• Psychiatry
• Pain Medicine

Background:

• Posttraumatic stress symptoms (PTSS) frequently co-occur with chronic pain.
• Previous research indicates white matter integrity alterations in the uncinate fasciculus and cingulum in separate chronic pain and PTSD studies.
• The specific relationship between chronic pain, PTSS, and white matter integrity is not fully understood.

Purpose of the Study:

• To investigate the association between PTSS severity and white matter microstructural integrity in individuals with chronic pain.
• To determine if white matter integrity differences in specific brain regions are common across various chronic pain conditions.

Main Methods:

• Diffusion weighted imaging was used to assess white matter integrity.
• Fractional anisotropy (FA) values were extracted from the uncinate fasciculus and cingulum (cingulate and hippocampal portions).
• Multiple linear regressions and moderation analyses were performed to examine group, PTSS severity, and their interactions on FA values.

Main Results:

• A significant group-by-PTSS interaction was found for uncinate fasciculus FA.
• Increased PTSS severity correlated with reduced uncinate fasciculus FA in controls, but not in the chronic pain group.
• No other significant associations were observed for the cingulum regions.

Conclusions:

• The findings suggest that while PTSS is associated with reduced uncinate fasciculus FA in healthy individuals, this relationship does not hold in people with chronic pain.
• Alternative neurobiological or psychological factors may influence white matter integrity in chronic pain patients experiencing PTSS.
• Further research is needed to explore these alternative mechanisms, potentially including comorbidities or pain-specific effects.