Pain processing in dementia and ageing: The role of sleep

• Applicant: Dr. Giulia Zerbini
• Subject Area: Biological Psychology and Cognitive Neuroscience
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 533337562

Individuals with Alzheimer’s disease (AD) show heightened pain vulnerability compared to cognitively unimpaired age-matched individuals. So far, it is not yet clear why AD-related increases in pain vulnerability occur and which factors could play a central role. When looking for possible influencing factors, sleep seems to be a very plausible, obvious and promising candidate. On the one hand, it is known that sleep disturbances are more prevalent in individuals with AD and, on the other hand, it has been shown that disturbed sleep can be associated with increased pain vulnerability. Importantly, AD is an age-dependent disease and both pain processing and sleep change with ageing as well. Thus, when investigating pain and sleep in the context of AD, both age-related processes and AD-pathology-related processes might play a role. To capture both processes, this grant application will investigate sleep and pain processing in healthy young and older individuals and in individuals with AD. The aim of this study is to investigate whether age-related and AD-related changes in pain processing (heightened pain vulnerability) are linked to changes in sleep. For this purpose, subjective and facial pain reactions to experimentally induced pressure and temperature stimuli will be compared between three groups (balanced for sex): young healthy (N=60, 18-40 years), older healthy (N=60, 65-85 years) and older participants with dementia (N=40, 65-85 years). The experimental pain protocol includes the assessment of pain threshold, pain responses to mild and moderate pain stimuli and endogenous pain inhibition. Sleep will be recorded using questionnaires as well as polysomnography to record sleep architecture (2 nights) and actigraphy to record general sleep behavior (14 nights). The following hypotheses are to be tested: Age-related changes in experimental pain processing can be in part explained by changes in sleep behavior and sleep architecture (group comparison: young healthy vs. old healthy individuals). AD-related changes in experimental pain processing can be in part explained by changes in sleep behavior and sleep architecture. The same sleep variables described for hypothesis i) as well as other variables that are affected specifically by AD (e.g., disrupted sleep-wake cycle) will be assessed as mediators of the relationship between dementia and pain (group comparison: older healthy individuals vs older individuals with AD). The results of this project can help to gain important knowledge about the role of sleep for the heightened pain vulnerability in ageing and in people with dementia. The two group comparisons can provide information on whether sleep should be generally considered and treated in geriatric pain therapy or only specifically for the pain therapy of individuals with dementia.

• DFG Programme: Research Grants
• Co-Investigators: Professorin Dr. Miriam Kunz; Professor Dr. Stefan Lautenbacher