Thermal Grill Illusion in Chronic Lower Back Pain: A Case-Control Study

Area of Science:

• Neuroscience
• Pain Research
• Clinical Medicine

Background:

• Chronic lower back pain (CLBP) affects a significant portion of the population, often involving complex central pain mechanisms.
• The thermal grill illusion (TGI) is a valuable experimental tool for investigating pain perception and central sensitization.

Purpose of the Study:

• To evaluate the perception of TGI-related sensations in patients with CLBP.
• To compare TGI perception between individuals with CLBP and healthy controls.
• To explore correlations between TGI perception and clinical measures of low back pain and quality of life.

Main Methods:

• Sixty-six patients with CLBP and 22 healthy participants underwent TGI testing.
• Participants rated sensations including warmth/heat, cold, unpleasantness, pain, burning, stinging, and prickling using a visual analog scale (VAS).
• CLBP patients completed the Oswestry Disability Index (ODI) and the 12-Item Short Form Survey (SF-12).

Main Results:

• The CLBP group reported significantly lower intensity for warmth/heat, unpleasantness, and pain sensations during TGI compared to controls.
• Specifically, burning sensations were perceived less intensely in the CLBP group (2.77 vs 4.55, P=0.016).
• Significant correlations were found between ODI scores and unpleasantness (r=0.381, P=0.002) and prickling sensations (r=0.263, P=0.033).
• The mental component score of the SF-12 correlated with warmth/heat (r=-0.246, P=0.046), unpleasantness (r=-0.292, P=0.017), pain (r=-0.292, P=0.017), and burning sensations (r=-0.280, P=0.023).

Conclusions:

• Individuals with CLBP exhibit altered TGI perception, suggesting changes in central pain processing.
• These findings highlight the potential utility of TGI in assessing centralized pain mechanisms in CLBP.
• The results may aid clinicians in evaluating the efficacy of interventions for managing centralized low back pain.