How do patients with Alzheimer's disease imagine their pain?

INTRODUCTION Pain is underdiagnosed and undertreated in patients with Alzheimer's disease (AD). Pain management is of major importance in this population to limit behavioral and functional consequences. Our study aimed to assess the capacity of AD patients to represent pain using a questionnaire exploring daily painful situations and to determine the most appropriate pain scale assessment. METHODS Twenty-eight patients with mild AD, 21 with moderate AD and 28 matched controls underwent the Situation Pain Questionnaire (SP-Q) and assessed imaginary pain with 4 pain scales. Two scores were compared between the 3 groups: the P(A) discrimination score and the response bias β score. P(A) reflects the degree of discrimination between high-pain and low-pain events, whereas the β score means the degree to which situations are considered as painful. RESULTS Our results showed that AD patients hardly discriminated the high from low-pain events. Compared to controls, the mean P(A) score was significantly lower for Mild AD (p<.03) and Moderate AD (p<.004). In addition, the β score indicated that the response bias is higher for AD patients (p<.01) in that they overestimated the level of pain. CONCLUSION The present results suggest that patients with Mild and Moderate AD are able to recognize and assess an imagined painful situation even though their pain tolerance is lower than that of controls. The pain scales used should be chosen according to the cognitive, sensorial and personal profiles of the patients.