Quantitative sensory testing and pain tolerance in patients with mild to moderate Alzheimer disease compared to healthy control subjects

Effects of hippocampal damage on pain perception in a rat model of Alzheimer's disease induced by amyloid-β and ibotenic acid injection into the hippocampus

Patients with Alzheimer's disease (AD) present with a variety of symptoms, including core symptoms as well as behavioral and psychological symptoms. Somatosensory neural systems are generally believed to be relatively unaffected by AD until late in the course of the disease; however, somatosensory perception in patients with AD is not yet well understood. One factor that may complicate the assessment of somatosensory perception in humans centers on individual variations in pathological and psychological backgrounds. It is therefore necessary to evaluate somatosensory perception using animal models with uniform status. In the current study, we focused on the hippocampus, the primary site of AD. We first constructed a rat model of AD model using bilateral hippocampal injections of amyloid-β peptide 1-40 and ibotenic acid; sham rats received saline injections. The Morris water maze test was used to evaluate memory impairment, and the formalin test (1 % or 4 % formalin) and upper lip von Frey test were performed to compare pain perception between AD model and sham rats. Finally, histological and immunohistochemical methods were used to evaluate tissue damage and neuronal activity, respectively, in the hippocampus. AD model rats showed bilateral hippocampal damage and had memory impairment in the Morris water maze test. Furthermore, AD model rats exhibited significantly less pain-related behavior in phase 2 (the last 50 min of the 60-minute observation) of the 4 % formalin test compared with the sham rats. However, no significant changes were observed in the von Frey test. Immunohistochemical observations of the trigeminal spinal subnucleus caudalis after 4 % formalin injection revealed significantly fewer c-Fos-immunoreactive cells in AD model rats than in sham rats, reflecting reduced neuronal activity. These results indicate that AD model rats with hippocampal damage have reduced responsiveness to persistent inflammatory chemical stimuli to the orofacial region.

The interactive effects of different exercises and hawthorn consumption on the pain threshold of TMT-induced Alzheimer male rats

Exercise increases the pain threshold in healthy people. However, the pain threshold modulation effect of exercise and hawthorn is unclear because of its potential benefits in people with persistent pain, including those with Alzheimer's disease. Accordingly, after the induction of Alzheimer's disease by trimethyl chloride, male rats with Alzheimer's disease were subjected to a 12-week training regimen consisting of resistance training, swimming endurance exercises, and combined exercises. In addition, hawthorn extract was orally administered to the rats. Then, their pain threshold was evaluated using three Tail-flick, Hot-plate, and Formalin tests. Our results showed that Alzheimer's decreased the pain threshold in all three behavioral tests. Combined exercise with hawthorn consumption had the most statistically significant effect on Alzheimer's male rats' pain threshold in all three experiments. A combination of swimming endurance and resistance exercises with hawthorn consumption may modulate hyperalgesia in Alzheimer's rats. Future studies need to determine the effects of these factors on the treatment and/or management of painful conditions.

Placebo analgesia and nocebo hyperalgesia in patients with Alzheimer disease and healthy participants

ABSTRACT

The role of placebo analgesia and nocebo hyperalgesia in patients with Alzheimer disease (AD) is largely unknown, with only few studies in the area. Therefore, this study aims to investigate to which extent placebo analgesia and nocebo hyperalgesia effects are present in patients experiencing mild-to-moderate AD. Twenty-one patients with AD (test population) and 26 healthy participants (HP; design validation) were exposed to thermal pain stimulation on 3 test days: Lidocaine condition (open/hidden lidocaine administration), capsaicin condition (open/hidden capsaicin administration), and natural history (no treatment), in a randomized, within-subject design. Open lidocaine and open capsaicin were accompanied by verbal suggestions for pain relief and pain increase, respectively. Expected pain and actual pain intensity were measured on a numerical rating scale (0-10). Placebo and nocebo effects were calculated as pain differences in open-hidden lidocaine and capsaicin, respectively, controlled for no treatment. Healthy participants obtained a placebo effect ( P = 0.01) and a trend for a nocebo effect ( P = 0.07). Patients with AD did not obtain a placebo effect ( P = 0.44) nor a significant nocebo effect ( P = 0.86). Healthy participants expected lower and higher pain with open vs hidden lidocaine and capsaicin, respectively ( P < 0.001). The same expectation effects were seen in patients with AD (open vs hidden lidocaine, P = 0.008; open vs hidden capsaicin, P < 0.001). With a well-controlled experimental setting, this study suggests that patients with AD may not experience placebo analgesia effects. Nocebo hyperalgesia effects in patients with AD needs further research. These findings may have implications for the conduction of clinical trials and the treatment of patients with AD in clinical practice.

Perspectives on pain in Down syndrome

Down syndrome (DS) or trisomy 21 is a genetic condition often accompanied by chronic pain caused by congenital abnormalities and/or conditions, such as osteoarthritis, recurrent infections, and leukemia. Although DS patients are more susceptible to chronic pain as compared to the general population, the pain experience in these individuals may vary, attributed to the heterogenous structural and functional differences in the central nervous system, which might result in abnormal pain sensory information transduction, transmission, modulation, and perception. We tried to elaborate on some key questions and possible explanations in this review. Further clarification of the mechanisms underlying such abnormal conditions induced by the structural and functional differences is needed to help pain management in DS patients.

Psychophysics of Pain: A Methodological Introduction

For over 100 years, psychophysics ..÷ the scientific study between physical stimuli and sensation ... has been successfully employed in numerous scientific and healthcare disciplines, as an objective measure of sensory phenomena. This manuscript provides an overview of fundamental psychophysical concepts, emphasizing pain and research application..÷defining common terms, methods, and procedures.Psychophysics can provide systematic and objective measures of sensory perception that can be used by nursing scientists to explore complex, subjective phenomena..÷such as pain perception. While there needs to be improved standardization of terms and techniques, psychophysical approaches are diverse and may be tailored to address or augment current research paradigms. The interdisciplinary nature of psychophysics..÷like nursing..÷provides a unique lens for understanding how our perceptions are influenced by measurable sensations. While the quest to understand human perception is far from complete, nursing science has an opportunity to contribute to pain research by using the techniques and methods available through psychophysical procedures.

How to Prevent and/or Revert Alzheimer's Disease Continuum During Preclinical Phases

The development of Alzheimer's disease (AD) follows three consecutive phases: namely preclinical, prodromal or mild cognitive impairment (MCI), and dementia. In addition, the preclinical phase can be divided into subphases related to the presence of biomarkers that appear at different points before the onset of MCI. Indeed, an early risk factor could promote the appearance of additional ones through a continuum. The presence of various risk factors may trigger specific biomarkers. In this review, we comment on how modifiable risk factors for AD may be reverted, thus correlating with a possible decrease in the specific biomarkers for the disease. Finally, we discuss the development of a suitable AD prevention strategy by targeting modifiable risk factors, thereby increasing the level of "precision medicine" in healthcare systems worldwide.

Chronic pain in Alzheimer's disease: Endocannabinoid system

Chronic pain, one of the most common reasons adults seek medical care, has been linked to restrictions in mobility and daily activities, dependence on opioids, anxiety, depression, sleep deprivation, and reduced quality of life. Alzheimer's disease (AD), a devastating neurodegenerative disorder (characterized by a progressive impairment of cognitive functions) in the elderly, is often co-morbid with chronic pain. AD is one of the most common neurodegenerative disorders in the aged population. The reported prevalence of chronic pain is 45.8% of the 50 million people with AD. As the population ages, the number of older people who experience AD and chronic pain will also increase. The current treatment options for chronic pain are limited, often ineffective, and have associated side effects. This review summarizes the role of the endocannabinoid system in pain, its potential role in chronic pain in AD, and addresses gaps and future directions.

Chronic pain in people living with dementia: challenges to recognising and managing pain, and personalising intervention by phenotype

Pain is common in people with dementia, and pain can exacerbate the behavioural and psychological symptoms of dementia. Effective pain management is challenging, not least in people with dementia. Impairments of cognition, communication and abstract thought can make communicating pain unreliable or impossible. It is unclear which biopsychosocial interventions for pain management are effective in people with dementia, and which interventions for behavioural and psychological symptoms of dementia are effective in people with pain. The result is that drugs, physical therapies and psychological therapies might be either underused or overused. People with dementia and pain could be helped by assessment processes that characterise an individual's pain experience and dementia behaviours in a mechanistic manner, phenotyping. Chronic pain management has moved from a 'one size fits all' approach, towards personalised medicine, where interventions recommended for an individual depend upon the key mechanisms underlying their pain, and the relative values they place on benefits and adverse effects. Mechanistic phenotyping through careful personalised evaluation would define the mechanisms driving pain and dementia behaviours in an individual, enabling the formulation of a personalised intervention strategy. Central pain processing mechanisms are particularly likely to be important in people with pain and dementia, and interventions to accommodate and address these may be particularly helpful, not only to relieve pain but also the symptoms of dementia.

The Hand-Withdrawal-Method - An adapted and simplified method of limits for behavioral heat pain assessment

The method-of-limits (MLI) is an established psychophysical procedure, for example for determining thermal thresholds. The standard MLI relies on fixating the thermode at the stimulation site by means of a strap and requires the participant to terminate the increase in heat by pressing a button. This, however, raises concerns regarding safety and task complexity in specific populations, such as cognitively impaired individuals, people with high fear of pain or young children (< 6 years). In this study, we aimed at developing a simplified version of the commonly used MLI for testing heat pain threshold (HPT) and tolerance (HPTol), and at validating it as a first step in healthy adults. Heating is terminated by withdrawing the hand from the heat probe, thereby ensuring maximum control and safety. For validation, HPTs and HPTols were assessed with the novel "hand-withdrawal-method" (HWM) and compared to the standard MLI, using a within-subject design. Additionally, as one potential research area in which the HWM may be used, we explored expectancy-induced placebo hypoalgesic effects by comparing results of standard MLI with those of HWM. Our data confirm good concordance between the 2 methods. For none of the outcomes significant differences between the 2 methods were found. PERSPECTIVE: In the present study in healthy adults, an adapted simplified and safe method of limits was demonstrated to be equivalent to the standard method-of-limits. This novel behavioral "hand-withdrawal-method" seems promising for future investigations of pain sensitivity and placebo effects, especially for specific populations such as young children.

Increased pain unpleasantness and pain-related fMRI activation in the periaqueductal gray in Alzheimer's disease

Background

Pain continues to be underrecognized and undertreated in people with Alzheimer's disease (AD). The periaqueductal gray (PAG) is essential to pain processing and modulation yet is damaged by AD. While evidence exists of altered neural processing of pain in AD, there has not been a focused investigation of the PAG during pain in people with AD.

Purpose

To investigate the role of the PAG in sensory and affective pain processing for people living with AD.

Methods

Participants from a larger study completed pain psychophysics assessments and then a perceptually-matched heat pain task (warmth, mild, and moderate pain) during a functional MRI scan. In this cross-sectional study, we examined blood oxygenation level-dependent (BOLD) responses in the PAG and other pain-related regions in participants with AD (n = 18) and cognitively intact older adults (age- and sex-matched, n = 18). Associations of BOLD percent signal change and psychophysics were also examined.

Results

There were significant main effects of AD status on the temperature needed to reach each perception of warmth or pain, where people with AD reached higher temperatures. Furthermore, participants with AD rated mild and moderate pain as more unpleasant than controls. PAG BOLD activation was greater in AD relative to controls during warmth and mild pain percepts. No significant differences were found for moderate pain or in other regions of interest. Greater PAG activation during mild pain was associated with higher affective/unpleasantness ratings of mild pain in participants with AD but not in controls.

Conclusion

Results suggest a role for the PAG in altered pain responses in people with AD. The PAG is the primary source of endogenous opioid pain inhibition in the neuroaxis, thus, altered PAG function in AD suggests possible changes in descending pain inhibitory circuits. People with AD may have a greater risk of suffering from pain compared to cognitively intact older adults.

Effect of acupuncture on brain regions modulation of mild cognitive impairment: A meta-analysis of functional magnetic resonance imaging studies

Background

As a non-pharmacological therapy, acupuncture has significant efficacy in treating Mild Cognitive Impairment (MCI) compared to pharmacological therapies. In recent years, advances in neuroimaging techniques have provided new perspectives to elucidate the central mechanisms of acupuncture for MCI. Many acupuncture brain imaging studies have found significant improvements in brain function after acupuncture treatment of MCI, but the underlying mechanisms of brain regions modulation are unclear.

Objective

A meta-analysis of functional magnetic resonance imaging studies of MCI patients treated with acupuncture was conducted to summarize the effects of acupuncture on the modulation of MCI brain regions from a neuroimaging perspective.

Methods

Using acupuncture, neuroimaging, magnetic resonance, and Mild Cognitive Impairment as search terms, PubMed, EMBASE, Web of Science, Cochrane Library, Cochrane Database of Systematic Reviews, Cochrane Database of Abstracts of Reviews of Effects (DARE), Google Scholar, China National Knowledge Infrastructure (CNKI), China Biology Medicine disk (CBM disk), Wanfang and Chinese Scientific Journal Database (VIP) for brain imaging studies on acupuncture on MCI published up to April 2022. Voxel-based neuroimaging meta-analysis of fMRI data was performed using voxel-based d Mapping with Permutation of Subject Images (SDM-PSI), allowing for Family-Wise Error Rate (FWER) correction correction for correction multiple comparisons of results. Subgroup analysis was used to compare the differences in brain regions between the acupuncture treatment group and other control groups. Meta-regression was used to explore demographic information and altered cognitive function effects on brain imaging outcomes. Linear models were drawn using MATLAB 2017a, and visual graphs for quality evaluation were produced using R software and RStudio software.

Results

A total of seven studies met the inclusion criteria, with 94 patients in the treatment group and 112 patients in the control group. All studies were analyzed using the regional homogeneity (ReHo) method. The experimental design of fMRI included six task state studies and one resting-state study. The meta-analysis showed that MCI patients had enhanced activity in the right insula, left anterior cingulate/paracingulate gyri, right thalamus, right middle frontal gyrus, right median cingulate/paracingulate gyri, and right middle temporal gyrus brain regions after acupuncture treatment. Further analysis of RCT and longitudinal studies showed that Reho values were significantly elevated in two brain regions, the left anterior cingulate/paracingulate gyrus and the right insula, after acupuncture. The MCI group showed stronger activity in the right supramarginal gyrus after acupuncture treatment compared to healthy controls. Meta-regression analysis showed that the right anterior thalamic projection ReHo index was significantly correlated with the MMSE score after acupuncture treatment in all MCI patients.

Conclusions

Acupuncture therapy has a modulating effect on the brain regions of MCI patients. However, due to the inadequate experimental design of neuroimaging studies, multi-center neuroimaging studies with large samples are needed better to understand the potential neuroimaging mechanisms of acupuncture for MCI. In addition, machine learning algorithm-based predictive models for evaluating the efficacy of acupuncture for MCI may become a focus of future research.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022287826, identifier: CRD 42022287826.

Caffeine Attenuates Electroacupuncture Effect on Pressure Pain Threshold and Tolerance in Healthy Individuals: A Randomized Controlled Trial

Introduction

The effect of caffeine on acupuncture analgesia in humans is unclear. This study aimed to investigate whether caffeine-containing beverage intake influences the effect of electroacupuncture (EA) on static quantitative sensory testing (QST) and dynamic QST in healthy subjects.

Methods

A total of 40 healthy subjects were enrolled and randomly assigned to receive coffee containing moderate doses of caffeine (coffee group) or non-caffeinated juice (juice group) for 4 weeks. The primary outcome measures were the pressure pain threshold (PPT), pressure pain tolerance (PPTo), and heat pain threshold (HPT) as static QST parameters. Numerical rating scales (NRS) of heat stimulus and nociceptive flexor reflex (RIII reflex), as parameters of dynamic QST, were also examined. EA stimulation with tolerance intensity was performed at ST36 (Zusanli)-GB34 (Yanglingquan) points at weeks 0, 2, and 4. PPT, PPTo, and HPT were detected pre- and post- EA. The NRS scores were examined pre-, during, and post-EA, and 1 min after EA was completed. The RIII reflex was examined pre- and 1–5 min post-EA.

Results

At week 0, both groups showed increased PPT and PPTo and decreased NRS scores of heat stimuli and RIII reflex after EA, but HPT was not affected. After 4 weeks, the effects of EA on PPT and PPTo were attenuated in the coffee group compared to the juice group, whereas the effect of EA on the NRS scores and RIII reflex were not influenced. There was no significant difference found at week 2 for these indications. EA also did not affect the HPT in both groups at week 4.

Conclusion

Moderate caffeine intake reduced the effects of EA on PPT and PPTo in healthy subjects.

Quantitative Sensory Testing Across Chronic Pain Conditions and Use in Special Populations

Chronic pain imposes a significant burden to the healthcare system and adversely affects patients' quality of life. Traditional subjective assessments, however, do not adequately capture the complex phenomenon of pain, which is influenced by a multitude of factors including environmental, developmental, genetic, and psychological. Quantitative sensory testing (QST), established as a protocol to examine thermal and mechanical sensory function, offers insight on potential mechanisms contributing to an individual's experience of pain, by assessing their perceived response to standardized delivery of stimuli. Although the use of QST as a research methodology has been described in the literature in reference to specific pain populations, this manuscript details application of QST across a variety of chronic pain conditions. Specific conditions include lower extremity chronic pain, knee osteoarthritis, chronic low back pain, temporomandibular joint disorder, and irritable bowel syndrome. Furthermore, we describe the use of QST in placebo/nocebo research, and discuss the use of QST in vulnerable populations such as those with dementia. We illustrate how the evaluation of peripheral sensory nerve function holds clinical promise in targeting interventions, and how using QST can enhance patient education regarding prognostic outcomes with particular treatments. Incorporation of QST methodology in research investigations may facilitate the identification of common mechanisms underlying chronic pain conditions, guide the development of non-pharmacological behavioral interventions to reduce pain and pain-related morbidity, and enhance our efforts toward reducing the burden of chronic pain.

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

OBJECTIVE

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). This study compared thermal pain psychophysics between a cohort of vascular dementia (VaD) patients and healthy control (HC) subjects.

DESIGN

Single center, cross-sectional, between-subjects design.

SUBJECTS

Verbally communicative, probable VaD patients (N = 23) and age- and sex-matched HC (N = 23).

METHODS

A thermal psychophysics protocol assessed "mild pain" and "moderate pain" thresholds (oC temperature) and associated unpleasantness ratings (0-20 scale) in both VaD and HC groups. Psychophysics were compared between groups by way of a mixed-effects analysis, controlling for depressive symptoms.

RESULTS

There were no significant differences between groups for pain thresholds (main effect p = 0.086, Cohen's d: mild = 0.55, moderate = 0.27). However, 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).

CONCLUSIONS

These results are consistent with prior observational findings suggesting VaD may make patients more susceptible to pain, particularly its affective component.

Pain Processing in Cognitive Impairment and Its Association with Executive Function and Memory: Which Neurocognitive Factor Takes the Lead?

It is well established that individuals with cognitive impairment present with disturbed forms of pain processing of still unknown origin. As a neurocognitive factor, executive functions have become favored candidates for explanation. For further insights, we aimed at comparing executive functions and memory in their association with parameters indicating onset and escalation of pain perception. Subjective ratings of experimentally induced pressure pain applied in ascending series were assessed in older individuals with (N = 32) and without mild cognitive impairments (MCI) (N = 32). We investigated whether executive functioning (Trail Making Test-B (TMT-B), semantic fluency) or memory (word list and figure recall) were more closely linked to the onset and the escalation of pain. For the MCI group, a strong linkage between pain responses and the TMT-B could be found, i.e., poor test performance was associated with weak pain onset but strong pain escalation. The contribution of memory functions was less substantial and systematic. The prominent role of executive function for pain processing in individuals with MCI could be replicated by a test of cognitive flexibility. This lack of adaptability let individuals with MCI be less vigilant to pain at the beginning but allows for escalating pain in the further course. Thus, being first not sufficiently prepared and later overwhelmed as regards pain may be an early problem in MCI individuals with reduced executive functioning.

Pain processing in older adults with dementia-related cognitive impairment is associated with frontal neurodegeneration

Experimental pain research has shown that pain processing seems to be heightened in dementia. It is unclear which neuropathological changes underlie these alterations. This study examined whether differences in pressure pain sensitivity and endogenous pain inhibition (conditioned pain modulation (CPM)) between individuals with a dementia-related cognitive impairment (N=23) and healthy controls (N=35) are linked to dementia-related neurodegeneration. Pain was assessed via self-report ratings and by analyzing the facial expression of pain using the Facial Action Coding System. We found that cognitively impaired individuals show decreased CPM inhibition as assessed by facial responses compared to healthy controls, which was mediated by decreased gray matter volume in the medial orbitofrontal and anterior cingulate cortex in the patient group. This study confirms previous findings of intensified pain processing in dementia when pain is assessed using non-verbal responses. Our findings suggest that a loss of pain inhibitory functioning caused by structural changes in prefrontal areas might be one of the underlying mechanisms responsible for amplified pain responses in individuals with a dementia-related cognitive impairment.

Chronic pain and cognitive impairment: a cross-sectional study in people living with HIV

Cognitive impairment and chronic pain are amongst the most prevalent neurological sequelae of HIV infection, yet little is understood about the potential bidirectional relationship between the two conditions. Cognitive dysfunction can occur in chronic pain populations whilst those with cognitive impairment can display modified responses to experimentally induced painful stimuli. To date, this has not been explored in HIV cohorts.This study aimed to identify any contribution of chronic pain to cognitive impairment in HIV and to determine differences in pain characteristics between those with and without cognitive dysfunction.This was an observational cohort study involving people living with HIV (n = 148) in the United Kingdom. Participants underwent validated questionnaire-based measurement of pain severity, interference and symptom quality as well as conditioned pain modulation and quantitative sensory testing. All participants completed a computer-based cognitive function assessment.Fifty-seven participants met the criteria for cognitive impairment and 73 for chronic pain. The cognitive impairment group had a higher prevalence of chronic pain (p = 0.004) and reported more neuropathic symptoms (p = 0.001). Those with chronic pain performed less well in emotional recognition and verbal learning domains. The interaction identified between chronic pain and cognitive dysfunction warrants further exploration to identify causal links or shared pathology.

Experimentally evoked pain in Alzheimer's disease

BACKGROUND

Pain continues to be underrecognized and undertreated in Alzheimer's disease (AD) while existing guidance about pain assessment and management in dementia is not widespread. Brain regions involved in pain processing and modulation are damaged during AD, and the pain experience in AD is not well understood. Experimental pain studies using psychophysics can further our understanding of the pain experience in AD, which may lead to improved assessment and management of pain in people living with AD.

OBJECTIVE

A systematic review was conducted to explicate the current understanding of experimentally evoked pain in AD from primary research using psychophysical methods.

DATA SOURCES

Peer-reviewed publications were found via PubMed, CINAHL, and PsycINFO. A total of 18 primary research, peer-reviewed full articles that met inclusion criteria were included, representing 929 total participants.

CONCLUSIONS

Experimentally evoked pain in people with AD demonstrates that despite cognitive impairment and a reduced ability to effectively communicate, individuals with AD experience pain similar to or more unpleasant than cognitively intact older adults. This may mean amplified pain unpleasantness in people with AD.

IMPLICATIONS FOR PRACTICE

Our current best practices need to be widely disseminated and put into clinical practice. Self-report of pain continues to be the gold standard, but it is ineffective for noncommunicative patients and those unable to understand pain scales or instructions because of memory/cognitive impairment. Instead, pain treatment should be ethically initiated based on patient reports and behaviors, caregiver/surrogate reports, review of the medical record for painful conditions, analgesic trials, and regular reassessments.

Predictors of quality of life and attitude to ageing in older adults with and without dementia

OBJECTIVES

This study explored the quality of life (QoL) and attitudes to aging in older adults with and without dementia, and ascertained the main factors that predict QoL and attitude to ageing.

METHODS

A cross-sectional study involving 563 community-dwelling adults with (PwD) and without dementia (PwoD) >60 years of age was conducted in three Czech regions. A tools battery including the Quality of Life-Alzheimer's Disease Scale, Geriatric Depression Scale, Patient Dignity Inventory, Attitude to Aging Questionnaire (AAQ), Short Physical Performance Battery, and Barthel Index, were administered.

RESULTS

PwD had worse scores in QoL and AAQ (both p = 0.0001). Less depression (p < 0.001), better sense of dignity (p < 0.05), and lower pain (p < 0.05) in PwoD predicted better scoring for QoL and AAQ. Physical ability in PwoD (p < 0.05), living alone (p < 0.05) and self-sufficiency (p < 0.001) in PwDwere predictors influencing QoL.Age (p < 0.01) in PwoD, gender (p < 0.05) and physical ability (p < 0.001) in PwD influenced AAQ.

CONCLUSIONS

This research is the first study to show that dignity can influence the QoL and attitude to aging in community-dwelling older adults. Our findings suggest that depression and dignity are common predictors of QoL and AAQ in older adults with and without dementia.

Comparisons of neuroinflammation, microglial activation, and degeneration of the locus coeruleus-norepinephrine system in APP/PS1 and aging mice

BACKGROUND

The role of microglia in Alzheimer's disease (AD) pathogenesis is becoming increasingly important, as activation of these cell types likely contributes to both pathological and protective processes associated with all phases of the disease. During early AD pathogenesis, one of the first areas of degeneration is the locus coeruleus (LC), which provides broad innervation of the central nervous system and facilitates norepinephrine (NE) transmission. Though the LC-NE is likely to influence microglial dynamics, it is unclear how these systems change with AD compared to otherwise healthy aging.

METHODS

In this study, we evaluated the dynamic changes of neuroinflammation and neurodegeneration in the LC-NE system in the brain and spinal cord of APP/PS1 mice and aged WT mice using immunofluorescence and ELISA.

RESULTS

Our results demonstrated increased expression of inflammatory cytokines and microglial activation observed in the cortex, hippocampus, and spinal cord of APP/PS1 compared to WT mice. LC-NE neuron and fiber loss as well as reduced norepinephrine transporter (NET) expression was more evident in APP/PS1 mice, although NE levels were similar between 12-month-old APP/PS1 and WT mice. Notably, the degree of microglial activation, LC-NE nerve fiber loss, and NET reduction in the brain and spinal cord were more severe in 12-month-old APP/PS1 compared to 12- and 24-month-old WT mice.

CONCLUSION

These results suggest that elevated neuroinflammation and microglial activation in the brain and spinal cord of APP/PS1 mice correlate with significant degeneration of the LC-NE system.

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 behavioural 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 four pain scales. Two scores were compared between the three 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 < 0.03) and Moderate AD (p < 0.004). In addition, the β score indicated that the response bias is higher for AD patients (p < 0.01) 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.

SIGNIFICANCE

The present research is significant because it examines how patients with Alzheimer's disease understand and assess painful situations. Cognitive impairments can modify this ability. Pain is a sensory and subjective experience and to define its feeling can help us in our clinical practice.

Correlation between biomarkers of pain in saliva and PAINAD scale in elderly people with cognitive impairment and inability to communicate: descriptive study protocol

INTRODUCTION

Pain is an under-diagnosed problem in elderly people, especially in those with cognitive impairment who are unable to verbalise their pain. Although the Pain assessment in advanced dementia scale (PAINAD) scale is a tool recognised for its clinical interest in this type of patients, its correlation with the saliva biomarkers reinforced its utility. The aim of this research will be to correlate the scores of this scale with the levels of biomarkers of pain found in saliva samples of patients with cognitive impairment and inability to communicate.

METHODS AND ANALYSIS

This is an observational study. The level of pain will be evaluated using the PAINAD scale. Moreover, pain biomarkers, in particular secretory IgA and soluble tumour necrosis factor receptor type II, will be determined in saliva. Both assessments will be conducted in 75 patients aged over 65 years with advanced cognitive impairment and inability to communicate. The PAINAD scores will be correlated with the levels of these biomarkers of pain. A control group consisting of 75 healthy subjects aged over 65 years will be included in the study. Moreover, sociodemographic variables and variables related to pain, dementia and other clinical conditions will be recorded. The analysis will be performed with the statistical package SPSS V.22 and the software R.

ETHICS AND DISSEMINATION

The study has been reviewed and approved by the Andalusian Human Research Ethics Committee. In addition, this study has been financed by the Junta de Andalucía through a regional health research fund (Research code: PI-0357-2017). The results will be actively disseminated trough a high-impact journal in our study area, conference presentations and social media.

White matter hyperintensities are related to pain intensity in an outpatient memory clinic population: preliminary findings

Background: The association between pain and dementia is complicated and may depend on underlying brain pathology. It was hypothesized that both medial temporal atrophy (MTA) and global cortical atrophy (GCA) predicted no/mild pain, while white matter hyperintensities (WMH) predicted moderate/severe pain.

Objectives: To study the association between pain intensity and measures of brain pathology, more specifically MTA, GCA, and WMH.

Methods: In total, 115 consecutive patients visiting an outpatient memory clinic were included. In total, diagnoses included dementia (N=70), mild cognitive impairment (N=30), and subjective cognitive impairment (N=15). Without administering stimuli, pain intensity was assessed with the Brief Pain Inventory. MTA, GCA, and WMH were measured with a MRI visual rating scale. Logistic regression analyses to examine the relationship between WMH, MTA, GCA, and self-reported pain intensity (no/mild pain versus moderate/severe pain) were adjusted for confounders.

Results: Mean age of the patients was 81 years (IQR: 78–85, 53% female). Moderate/severe pain was reported by 23.5% and associated with greater WMH (OR =3.34, 95% CI =1.01–10.97, p=0.047), but not MTA or GCA.

Conclusions: In contrast to the present results, earlier studies have reported either a positive or negative relationship between pain and brain volume. It is suggested that the presence of dementia may explain the absence of a relationship between pain and brain volume. WMH is positively related with pain in an older memory outpatient population. Considering the small sample size, our findings should be interpreted with caution. Hence, our conclusions are preliminary findings, warranting future replication.

Pain, aging and dementia: Towards a biopsychosocial model

Dementia is a progressive disease associated with irreversible impairment and loss of cognitive abilities. About half of older people with dementia experience pain. In this paper, we propose that pain in older people with dementia can be conceptualized as the final result of the interaction of three heterogeneous phenomena, pain, aging, and dementia, which are created and influenced by the interactions of predisposing, lifelong, and current biopsychosocial factors. We review pain assessment in people with dementia using both self-report and observational/behavioral measures. We then review the biological/sensory, psychological (cognitive and affective) and social dimensions of pain in dementia. The available data suggest that dementia does not impact pain threshold or tolerance. To date, there is little research on the social dimension of pain in dementia. Changes in the affective domain in response to experimental pain have been contradictory with evidence supporting both increased and decreased unpleasantness and emotional responsiveness in people with dementia compared to healthy controls. Clinically, depression is a significant burden for older people with dementia and chronic pain. The relationship between pain and other neuropsychiatric symptoms is controversial, and there is insufficient evidence on which to base conclusions. Some of the most important dementia-related changes may arise in the cognitive domain, including impairments of semantic and episodic memory for pain, executive function, and pain anticipation. Changes in brain activation and interconnectivity support many of these conclusions. Despite methodological limitations, we conclude there are compelling preliminary data to support a biopsychosocial framework of pain and dementia. Future research directions, especially the need for improved assessment tools, are highlighted.

A Review of Pain Prevalence in Alzheimer's, Vascular, Frontotemporal and Lewy Body Dementias

BACKGROUND

Numerous studies have reported on pain in dementia. It has been hypothesized that pain perception differs between dementia subtypes, and therefore, the prevalence of pain differs between dementia subtypes. However, there remains a paucity of evidence on the differences in the prevalence of pain in different dementia subtypes. This review aimed to determine the prevalence of pain for the major dementia subtypes: Alzheimer's disease (AD), vascular dementia (VaD), frontotemporal dementia (FTD) and dementia with Lewy bodies (DLB).

SUMMARY

We found 10 studies that met our inclusion criteria. Most of these studies reported on AD; studies reporting the prevalence of pain in people with DLB were scarce, and for FTD, we found no studies. The sample-weighted prevalence of pain could only be calculated for AD, VaD and mixed dementia: AD 45.8% (95% confidence interval, CI: 33.4-58.5%), VaD 56.2% (95% CI: 47.7-64.4%) and mixed dementia 53.9% (95% CI: 37.4-70.1%).

KEY MESSAGES

Studies investigating the prevalence of pain in dementia subtypes were scarce; however, we found a high prevalence of pain in dementia without significant differences between the dementia subtypes. More studies are required to draw firm conclusions on the differences in the prevalence of pain between dementia subtypes.

Postoperative Treatment of Pain after Hip Fracture in Elderly Patients with Dementia

BACKGROUND/AIMS

Prior studies have shown that patients with dementia are at risk of receiving insufficient treatment for pain after a hip fracture. We therefore hypothesized that elderly hip fracture patients with dementia received less postoperative pain treatment than those without dementia.

METHOD

All patients (age ≥65 years) who had been operated on for a hip fracture in the Copenhagen University Hospital region in 2009 were included. Data about analgesic use for the first 72 h after surgery were acquired from the hospitals' electronic medication system and linked with information about dementia, comorbidity, and prior drug use.

RESULTS

A total of 1,507 patients were included, of which 296 (19.6%) suffered from dementia. Both groups were equally likely to receive paracetamol and opioids. Patients with dementia received lower doses of oral morphine equivalents during the first [dementia vs. no dementia: 29.0 (26.4-31.8) vs. 34.7 (33.1-36.4) mg, p = 0.001] and second [27.8 (25.4-30.5) vs. 31.2 (29.9-32.4) mg, p = 0.019] but not on the third postoperative day (p = 0.10).

CONCLUSION

The lower doses of opioids may reflect uncertainty about how to treat pain patients with dementia. Further guidance is needed, as inadequate treatment of pain may have adverse consequences.

Altered Behavioral and Autonomic Pain Responses in Alzheimer's Disease Are Associated with Dysfunctional Affective, Self-Reflective and Salience Network Resting-State Connectivity

While pain behaviors are increased in Alzheimer's disease (AD) patients compared to healthy seniors (HS) across multiple disease stages, autonomic responses are reduced with advancing AD. To better understand the neural mechanisms underlying these phenomena, we undertook a controlled cross-sectional study examining behavioral (Pain Assessment in Advanced Dementia, PAINAD scores) and autonomic (heart rate, HR) pain responses in 24 HS and 20 AD subjects using acute pressure stimuli. Resting-state fMRI was utilized to investigate how group connectivity differences were related to altered pain responses. Pain behaviors (slope of PAINAD score change and mean PAINAD score) were increased in patients vs.

CONTROLS

Autonomic measures (HR change intercept and mean HR change) were reduced in severe vs. mildly affected AD patients. Group functional connectivity differences associated with greater pain behavior reactivity in patients included: connectivity within a temporal limbic network (TLN) and between the TLN and ventromedial prefrontal cortex (vmPFC); between default mode network (DMN) subcomponents; between the DMN and ventral salience network (vSN). Reduced HR responses within the AD group were associated with connectivity changes within the DMN and vSN-specifically the precuneus and vmPFC. Discriminant classification indicated HR-related connectivity within the vSN to the vmPFC best distinguished AD severity. Thus, altered behavioral and autonomic pain responses in AD reflects dysfunction of networks and structures subserving affective, self-reflective, salience and autonomic regulation.

Low back pain in older adults: risk factors, management options and future directions

Low back pain (LBP) is one of the major disabling health conditions among older adults aged 60 years or older. While most causes of LBP among older adults are non-specific and self-limiting, seniors are prone to develop certain LBP pathologies and/or chronic LBP given their age-related physical and psychosocial changes. Unfortunately, no review has previously summarized/discussed various factors that may affect the effective LBP management among older adults. Accordingly, the objectives of the current narrative review were to comprehensively summarize common causes and risk factors (modifiable and non-modifiable) of developing severe/chronic LBP in older adults, to highlight specific issues in assessing and treating seniors with LBP, and to discuss future research directions. Existing evidence suggests that prevalence rates of severe and chronic LBP increase with older age. As compared to working-age adults, older adults are more likely to develop certain LBP pathologies (e.g., osteoporotic vertebral fractures, tumors, spinal infection, and lumbar spinal stenosis). Importantly, various age-related physical, psychological, and mental changes (e.g., spinal degeneration, comorbidities, physical inactivity, age-related changes in central pain processing, and dementia), as well as multiple risk factors (e.g., genetic, gender, and ethnicity), may affect the prognosis and management of LBP in older adults. Collectively, by understanding the impacts of various factors on the assessment and treatment of older adults with LBP, both clinicians and researchers can work toward the direction of more cost-effective and personalized LBP management for older people.

The Impact of Alzheimer's Disease on the Resting State Functional Connectivity of Brain Regions Modulating Pain: A Cross Sectional Study

BACKGROUND

It is currently unknown why people with Alzheimer's disease (AD) receive less pain medication and report pain less frequently.

OBJECTIVE

The purpose of this study was to determine the impact of AD on thermal psychophysics and resting-state functional connectivity (RSFC) among sensory, affective, descending modulatory, and default mode structures.

METHODS

Controls (n = 23, 13 = female) and age-matched people with AD (n = 23, 13 = females) underwent psychophysical testing to rate perceptions of warmth, mild, and moderate pain and then completed resting-state fMRI. Between groups analysis in psychophysics and RSFC were conducted among pre-defined regions of interest implicated in sensory and affective dimensions of pain, descending pain modulation, and the default mode network.

RESULTS

People with AD displayed higher thermal thresholds for warmth and mild pain but similar moderate pain thresholds to controls. No between-group differences were found for unpleasantness at any percept. Relative to controls, people with AD demonstrated reduced RSFC between the right posterior insula and left anterior cingulate and also between right amygdala and right secondary somatosensory cortex. Moderate pain unpleasantness reports were associated with increased RSFC between right dorsolateral prefrontal cortex and left ACC in controls only.

CONCLUSIONS

While AD had little effect on unpleasantness, people with AD had increased thermal thresholds, altered RSFC, and no association of psychophysics with RSFC in pain regions. Findings begin to elucidate that in people with AD, altered integration of pain sensation, affect, and descending modulation may, in part, contribute to decreased verbal pain reports and thus decreased analgesic administration.

Contact Heat Evoked Potentials (CHEPs) in Patients with Mild-Moderate Alzheimer's Disease and Matched Control--A Pilot Study

OBJECTIVE

Clinical studies have found that patients with Alzheimer's disease report pain of less intensity and with a lower affective response, which has been thought to be due to altered pain processing. The authors wished to examine the cerebral processing of non-painful and painful stimuli using somatosensory evoked potentials and contact heat evoked potentials in patients with Alzheimer's disease and in healthy elderly controls.

DESIGN

Case-control study

SETTING AND SUBJECTS

Twenty outpatients with mild-moderate Alzheimer's disease and in 17 age- and gender-matched healthy controls were included

METHOD

Contact heat evoked potentials and somatosensory evoked potentials were recorded in all subjects. Furthermore, warmth detection threshold and heat pain threshold were assessed. Patients and controls also rated quality and intensity of the stimuli.

RESULTS

The authors found no difference on contact heat evoked potential amplitude (P = 0.59) or latency of N2 or P2 wave (P = 0.62 and P = 0.75, respectively) between patients and controls. In addition, there was no difference in regard to pain intensity scores or pain quality. The patients and controls had similar warmth detection threshold and heat pain threshold. Somatosensory evoked potentials, amplitude, and latency were within normal range and similar for the two groups.

CONCLUSIONS

The findings suggest that the processing of non-painful and painful stimuli is preserved in patients with mild to moderate Alzheimer's disease.

Loss in Executive Functioning Best Explains Changes in Pain Responsiveness in Patients with Dementia-Related Cognitive Decline

There is ample evidence that dementia changes the processing of pain. However, it is not known whether this change in pain processing is related to the general decline in cognitive functioning or whether it may be related to specific domains of cognitive functioning. With the present study we tried to answer this question. We assessed different cognitive domains (orientation, memory, abstract thinking/executive function, aphasia and apraxia, and information processing speed) in 70 older patients with cognitive impairment (mild cognitive impairment up to moderate degrees of dementia). Pain responsiveness was assessed by measuring the nociceptive flexion reflex (NFR) threshold and facial responses to noxious electrical stimulation. Using regression analyses, we assessed which domain of cognitive functioning best predicted variance in pain responsiveness. Variance in pain responsiveness (NFR and facial expressions) was best explained by those items assessing executive functioning even when controlling for overall cognitive performance and memory functioning. The close association between executive functioning and pain responsiveness suggests that dementia-related neurodegeneration in prefrontal areas might result not only in reduced executive functioning but also in a loss of pain inhibitory potency, rendering the patient more vulnerable to pain. Our findings also suggest that pain assessment in dementia should be regularly completed by tests of cognitive functions.

Pain and temperature processing in dementia: a clinical and neuroanatomical analysis

Symptoms suggesting altered pain and temperature processing have been described in dementia diseases. Using a semi-structured caregiver questionnaire and MRI voxel-based morphometry in patients with frontotemporal degeneration or Alzheimer’s disease, Fletcher et al. show that these symptoms are underpinned by atrophy in a distributed thalamo-temporo-insular network implicated in somatosensory processing.

Symptoms suggesting altered processing of pain and temperature have been described in dementia diseases and may contribute importantly to clinical phenotypes, particularly in the frontotemporal lobar degeneration spectrum, but the basis for these symptoms has not been characterized in detail. Here we analysed pain and temperature symptoms using a semi-structured caregiver questionnaire recording altered behavioural responsiveness to pain or temperature for a cohort of patients with frontotemporal lobar degeneration (n = 58, 25 female, aged 52–84 years, representing the major clinical syndromes and representative pathogenic mutations in the C9orf72 and MAPT genes) and a comparison cohort of patients with amnestic Alzheimer’s disease (n = 20, eight female, aged 53–74 years). Neuroanatomical associations were assessed using blinded visual rating and voxel-based morphometry of patients’ brain magnetic resonance images. Certain syndromic signatures were identified: pain and temperature symptoms were particularly prevalent in behavioural variant frontotemporal dementia (71% of cases) and semantic dementia (65% of cases) and in association with C9orf72 mutations (6/6 cases), but also developed in Alzheimer’s disease (45% of cases) and progressive non-fluent aphasia (25% of cases). While altered temperature responsiveness was more common than altered pain responsiveness across syndromes, blunted responsiveness to pain and temperature was particularly associated with behavioural variant frontotemporal dementia (40% of symptomatic cases) and heightened responsiveness with semantic dementia (73% of symptomatic cases) and Alzheimer’s disease (78% of symptomatic cases). In the voxel-based morphometry analysis of the frontotemporal lobar degeneration cohort, pain and temperature symptoms were associated with grey matter loss in a right-lateralized network including insula (P < 0.05 corrected for multiple voxel-wise comparisons within the prespecified anatomical region of interest) and anterior temporal cortex (P < 0.001 uncorrected over whole brain) previously implicated in processing homeostatic signals. Pain and temperature symptoms accompanying C9orf72 mutations were specifically associated with posterior thalamic atrophy (P < 0.05 corrected for multiple voxel-wise comparisons within the prespecified anatomical region of interest). Together the findings suggest candidate cognitive and neuroanatomical bases for these salient but under-appreciated phenotypic features of the dementias, with wider implications for the homeostatic pathophysiology and clinical management of neurodegenerative diseases.

Pain in dementia: prevalence and associated factors: protocol of a multidisciplinary study

Background

Pain is a common problem in people with dementia, however the exact prevalence of pain in dementia subtypes, e.g. Alzheimer’s Disease (AD), Vascular Dementia (VaD), Frontotemporal Dementia (FTD) and dementia with Lewy Bodies (DLB), is unknown, as is the relation between pain and the different subtypes of dementia. In this study, the prevalence of pain in people with dementia will be investigated per dementia subtype and the relationship between the various subtypes of dementia and the presence of specific types of pain (i.e. musculoskeletal pain, neuropathic pain and orofacial pain) will be examined. Secondly, associations between various types of pain, cognitive functioning, neuropsychiatric symptoms and quality of life in people with dementia will be examined. A third purpose is to study the value of the assessment of autonomic responses in assessing pain in people with dementia. Finally, the effect of feedback to the attending physician on the presence of pain, based on examination by investigators with backgrounds in neuropsychology, geriatric dentistry and elderly care medicine, will be evaluated.

Methods/Design

A cross-sectional, partially longitudinal observational study in 400 participants with dementia, aged 60 years and older. Participants will be recruited from an outpatient memory clinic and dementia special care units. All participants will be examined by an elderly care medicine trainee, a dentist with experience in geriatric dentistry, and a neuropsychologist. The primary outcome is presence of pain. Secondary outcomes will include oral health, autonomic responses to pain stimulus, vital sensibility and gnostic sensibility, musculoskeletal examination, cognitive functioning, neuropsychiatric symptoms, and quality of life.

Discussion

This study will help to enhance our knowledge regarding the prevalence of different types of pain in different dementia subtypes i.e. AD, VaD, FTD and DLB. This study also aims to contribute to a better understanding of oral health status in people with dementia, the use of autonomic responses in the assessment of pain in people with dementia and the relationships between pain and cognitive symptoms, neuropsychiatric symptoms and quality of life in people with various dementia subtypes and in different stages of the disease.

Discrepancy between stimulus response and tolerance of pain in Alzheimer disease

BACKGROUND

Affective-motivational and sensory-discriminative aspects of pain were investigated in patients with mild to moderate Alzheimer disease (AD) and healthy elderly controls using the cold pressor test tolerance and repetitive stimuli of warmth and heat stimuli, evaluating the stimulus-response function.

METHODS

A case-control design was applied examining 33 patients with mild to moderate AD dementia and 32 healthy controls with the cold pressor test (4°C). Warmth detection threshold (WDT) and heat pain threshold (HPT) were assessed using 5 stimulations. A stimulus-response function was estimated using 4 incrementally increasing suprathreshold heat stimuli.

RESULTS

Cold pressor tolerance was lower in patients with AD dementia than in controls (p = 0.027). There were no significant differences between groups regarding WDT and HPT. Significant successive increases in HPT assessments indicated habituation (p < 0.0001), which was similar in the 2 groups (p = 0.85). A mixed model for repeated measures demonstrated that pain rating of suprathreshold stimuli depended on HPT (p = 0.0004) and stimulus intensity (p < 0.0001). Patients with AD dementia had significantly lower increases in pain ratings than controls during suprathreshold stimulation (p = 0.0072).

CONCLUSION

Our results indicate that AD dementia is not associated with a propensity toward development of sensitization or a lack of habituation, suggesting preservation of sensory-discriminative aspects of pain perception. The results further suggest that the attenuated cold pressor pain tolerance may relate to impairment of coping abilities. Paradoxically, we found an attenuated stimulus-response function, compared to controls, suggesting that AD dementia interferes with pain ratings over time, most likely due to memory impairment.

Depressive symptoms are associated with analgesic use in people with Alzheimer's disease: Kuopio ALSOVA study

Neuropsychiatric symptoms of Alzheimer's disease (AD) such as depression may be associated with pain, which according to the literature may be inadequately recognized and managed in this population. This study aimed to identify the factors associated with analgesic use in persons with AD; in particular, how AD severity, functional status, neuropsychiatric symptoms of AD, co-morbidities and somatic symptoms are associated with analgesic use. 236 community-dwelling persons with very mild or mild AD at baseline, and their caregivers, were interviewed over five years as part of the prospective ALSOVA study. Generalized Estimating Equations (GEEs) were used to estimate unadjusted and adjusted odds ratios (ORs) for the factors associated with analgesic use over a five year follow-up. The proportion of persons with AD using any analgesic was low (13.6%) at baseline and remained relatively constant during the follow-up (15.3% at Year 5). Over time, the most prevalent analgesic changed from non-steroidal anti-inflammatories (8.1% of persons with AD at Year 1) to acetaminophen (11.1% at Year 5). Depressive symptoms (measured by the Beck Depression Inventory, BDI) were independently associated with analgesic use, after effects of age, gender, education, AD severity, comorbidities and somatic symptoms were taken into account. For every one unit increase in BDI, the odds of analgesic use increased by 4% (OR = 1.04, 95% confidence interval CI = 1.02-1.07). Caregiver depressive symptoms were not statistically significantly associated with analgesic use of the person with AD. Depressive symptoms were significantly associated with analgesic use during the five year follow-up period. Possible explanations warranting investigation are that persons with AD may express depressive symptoms as painful somatic complaints, or untreated pain may cause depressive symptoms. Greater awareness of the association between depressive symptoms and analgesic use may lead to safer and more effective prescribing for these conditions.