A Cross-Sectional Study of Pain Sensitivity and Unpleasantness in People with Vascular Dementia

Abstract

Advanced age holds higher risk of both pain and dementia, with many studies finding dementia often heightens sensitivity to pain. VaD is the second most common type of dementia. Only a few observational or retrospective studies have examined pain responsiveness in VaD, suggesting it may increase pain unpleasantness (i.e., pain affect). We utilized a thermal psychophysics paradigm to examine "mild pain" and "moderate pain" thresholds (oC temperature) and associated unpleasantness ratings (0-20 scale) in a cohort of verbally-communicative, probable VaD patients (n=23). Responses in VaD patients were compared to age- and sex-matched healthy control responses (HC, n=23). Psychophysics were compared between groups by way of a mixed-effects analysis, controlling for depressive symptoms. We found a tendancy toward lower pain thresholds in the VaD group, driven by mild pain (main effect p=0.086, Cohen's d: mild = 0.55, moderate = 0.27). Unpleasantness ratings were higher in the VaD group compared to HC (main effect p=0.003; mild pain p=0.022, Cohen's d=0.79; moderate pain p=0.057, Cohen's d=0.6). We found experimental evidence for greater thermal pain sensitivity in VaD, driven by greater pain unpleasantness. These results are consistent with prior observational findings suggesting VaD may make patients more susceptible to pain, particularly its affective component.