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The following is a summary of “Painful distortions: people with painful knee osteoarthritis have biased visuospatial perception of the environment,” published in the April 2024 issue of Pain by MacIntyre et al.

Researchers conducted a retrospective study on the influence of pain intensity and fear on visuospatial perception modulation, with potential consequences for physical activity.

They compared visuospatial perception in 50 individuals suffering from painful knee osteoarthritis, and 50 pain-free controls matched for age and sex. Three virtual reality tasks were involved (estimating uphill and downhill steepness and a distance-on-hill measure). The study explored connections between visuospatial perception, clinical factors (pain intensity, fear levels), and behavior (wrist-worn accelerometry) within a larger group of patients with knee osteoarthritis (totaling 85).

The results showed that individuals with knee osteoarthritis tended to overestimate uphill (F₁₄₈₅ = 19.4, P<0.001) and downhill (F1,480 = 32.3, P<0.001) steepness compared to pain-free controls. However, there was no difference between the groups for distance-on-hill measures (U = 1273, P=0.61). A significant group x steepness interaction was observed for the downhill steepness task (F₄₄₈₀ = 3.11, P=0.02), indicating that overestimation in patients with knee osteoarthritis increased as downhill slopes became steeper. Results remained consistent after replication with all knee osteoarthritis (n = 85), though the downhill steepness interaction lost significance. In knee osteoarthritis individuals, higher state fear correlated with greater overestimation of downhill slope steepness (rho = 0.69, P<0.001), and increased visuospatial overestimation (distance-on-hill) was linked with lower levels of physical activity (rho = −0.22, P=0.045).

Investigators concluded that chronic pain likely alters environmental perception for protection, with steeper perceived inclines during heightened threat (fear or intensity), though the effect on actual behavior remains unclear.

Source: journals.lww.com/pain/abstract/9900/painful_distortions__people_with_painful_knee.577.aspx