Dementia is known as a clinical syndrome as a result of disease of the brain, usually of a progressive nature, which is characterised by disturbances of multiple higher cortical functions such as memory, thinking, orientation, comprehension, calculation, learning capacity, language and judgment (WHO, 2010). Alzheimer’s disease (AD) is the most common cause of dementia. However, other prevalent causes include vascular dementia (VaD), frontotemporal dementia (FTD) and Lewy body dementia.
Is the experience of pain different in individuals with Dementia?
A number of studies have found less reported pain in individuals with dementia compared to those without dementia (e.g., Parmelee, Smithy, & Katz, 1993; Scherder, Bouma, Borkent, & Rahman, 1999; Haasum, Fastbom, Fratiglioni, Kåreholt, & Johnell, 2011). It is important to note here that studies have emphasised that there is a reduction in reported pain as the severity of dementia increases and it has also been highlighted that pain in individuals with dementia frequently goes under-reported and is poorly detected.
In clinical practice, researchers have shown that individuals with dementia receive less pain medication (Morrison & Siu, 2000). An interesting study carried out by Oosterman and colleagues (2014) highlighted that the reasons for this are not yet clearly defined. This clearly requires urgent attention to address these gaps in our understanding. Some researchers have provided some possible explanations for why individuals with dementia receive less pain medication and are not identified as being in pain compared to their counterparts without dementia which will be discussed in turn below.
Do the neuropathological changes which occur in dementia have an impact on pain?
Pain assessment with individuals with dementia can be particularly difficult and complex given the symptom of this condition such as impaired ability to communicate. Therefore, commonly used assessment tools may not be appropriate for use (or difficult to use) with this particular group of individuals (Scherder, Sergeant, & Swaab, 2003; van Dalen-Kok et al., 2015). Another explanation for why pain goes undetected is that in patients with dementia, their pain tends to be exhibited as challenging behaviour (such as agitation or withdrawal) and are also known as neuropsychiatric symptoms (NPS) (e.g., Geda et al., 2013).
Is there neurodegeneration on central pain processing regions in the brain in individuals with dementia?
The question of whether there is less reporting of pain in individuals with dementia because of neurodegeneration of the regions of the brain which process pain is an interesting one. Some researchers have even argued that reported pain is lower in individuals with dementia due to some of the parts of their brain which processes pain is adversely impacted because of the disease. In other words, some of the regions of the brain responsible for processing pain suffer degeneration (e.g., Scherder, Sergeant, & Swaab, 2003) which results in the lowered levels of clinical pain ratings. Some support for this idea comes from some studies which have found normal pain detection but higher pain tolerance in individuals with Alzheimer’s disease (AD) (Benedetti et al., 1999).
Such evidence of degeneration of the regions of the brain responsible for processing pain in individuals with dementia have not been supported by more recent studies and calls this explanation into question. Comparing 14 patients with AD and 15 age-matched controls, Cole and colleagues (2006) found no support for reduced pain-related activity in the group of patients with AD compared with the age-matched controls. Surprisingly, patients with AD, when compared to the controls, exhibited increased amplitude and duration of pain-related activity in regions involved with sensory, affective and cognitive processing which highlights the possibility of a sustained attention to the noxious/painful stimulus. In other words, in individuals with AD there appears to be no evidence for any alterations in pain perception and processing. This raises concerns surrounding the current treatment approaches for pain in this vulnerable population (Cole et al., 2006). For instance, the impact of untreated pain in this group (Corbett, Husebo, Achterberg, Aarsland, Erdal, & Flo, 2014).
Is a degeneration of memory functions in individuals with dementia an explanation for why this group report less pain and it is poorly detected as a result?
Another explanation for the studies which have found differences in reported pain in individuals with dementia is that rather than reduced experiences of pain, individuals with dementia suffer cognitive impairments, specifically degeneration of memory functions, which impact on their ability to identify and report experiences of pain.
A recent study found support for this. Oosterman and colleagues (2014) were the first to demonstrate that semantic memory for pain is reduced in 26 individuals with dementia compared with 13 controls. Semantic memory is general world knowledge which is accumulated throughout our lives. In order to assess semantic memory for pain, the researchers used two subtests.
The first involved identifying painful situations from a standardised range of pictures. This Semantic Memory for Pain (SMP) assessment consisted of 16 pictures. Eight of the picture depict a painful situation, five a related non-painful situation, and three an unrelated (neutral) situation. All situations comprise of familiar events that people can experience in their everyday life including things like pinching one’s finger in a door, or catching one’s toe under a heavy object (Jackson et al., 2006). There were two ways in which the pictures varied. The first was how arousing the pictures were. In other words, whether the degree of excitement that the picture induces was either low, medium or high. The second way in which the pictures varied was the type of pain which the picture represented which could either be thermal or mechanical. Three pictures which were not related to any of the pain pictures were included which acted as controls as they represented neutral actions including: typing, knitting and kneading dough. For this SMP assessment involving all these 16 pictures, participants were tasked with indicating whether the picture they were being represented with involved a painful situation or not. The researchers used the following scoring criteria: “True positives” which is when the participant correctly identifies a pain picture, “True negatives” which is when the participant correctly rejects a non-painful picture, “False negatives” for when participants incorrectly rejects a pain picture and “False positives” when participants incorrectly identify a non-painful picture. Using the Wong–Baker FACES Pain Rating Scale (depicted here), for the ‘true positive” responses the participants had to imagine the level of pain that the situation would cause. Responses were coded as a “no responses” in cases where a participant was unable to indicate whether a picture represented a painful situation or not.
In the second part of the SMP in the study by Oosterman and colleagues (2014) participants were asked two open-ended questions: Q1. “What is pain?” and Q2. “Can you name different types of pain?” So being asked to describe the concept of pain (Oosterman, Hendriks, Scott, Lord, White, & Sampson, 2014). Firstly, they were asked whether they were currently in any pain at the moment. Following this measure of current pain, participants were then asked to indicate the intensity of their current pain using the FACES scale. The Pain Assessment in Advanced Dementia Scale (PAINAD) was completed by participants which is a behavioural scale developed to investigate pain in individuals with dementia who are not able to self-report because of communication difficulties (Warden, Hurley, & Volicer, 2003). There were five behavioural indicators of pain in total which the researchers scored on a 0–2-point rating scale during movement. Some examples of the movement could be moving from the bed to a chair or repositioning in bed.
What were the findings from Oosterman and colleagues (2014) interesting study?
Findings from the study suggest that individuals with dementia made fewer true positives, fewer true negatives and more false negatives. The individuals with dementia provided less detailed description of the concept of pain to Q1 (“What is pain?”) and used descriptions of affective aspects and the cause or nature of pain less frequently compared to the age- and sex-matched controls.. In their responses to Q2 (“Can you name different types of pain?”), the individuals with dementia were found to describe the location of their pain location less compared to the compared to the age- and sex-matched controls.
The group of individuals with dementia were found to have poorer performance on the pain picture identification task when compared to age- and sex-matched controls. Looking at individual scores rather than group overall scores, most of the individuals in the study with dementia exhibited an acceptable level of performance on the task. Specifically, demonstrating an above-chance level on the number of true positives or above-chance level on the total number correct [true positives + true negatives]. However, four of the individuals with dementia received scores of 0 or 1 given that, overall, they were not able to respond to the questions.
These alterations in the semantics of pain were also associated with the self-reported pain. Individuals with dementia who confirmed the presence of pain, were found to have better performance on the number of correctly identified pain pictures (whether they were either painful or non-painful). Not only did they display better performance on this but, when examining their concept of pain, they also exhibited more extensive descriptions. Crucially, there was a significantly and strong association between higher FACES current pain intensity scores and lower estimated pain induced by the painful situations in the pictures.
All these findings by Oosterman and colleagues (2014) are consistent with the theory that pain semantics are impacted in individuals with dementia. This has clear implications for care and treatment as it indicates that just asking questions regarding pain may be interpreted differently in individuals with dementia due to altered semantic knowledge abilities. This study highlights a qualitative difference in the concept of pain in individuals with dementia (Oosterman et al., 2014). The exact prevalence of pain across the different subtypes of dementia (e.g., AD, Vascular Dementia (VaD), Frontotemporal Dementia (FTD) and dementia with Lewy Bodies (DLB) has rarely been examined. Van Kooten and colleagues (2015) have published a protocol for their study which plans to investigate the prevalence of pain in individuals with dementia (n = 400, 60 years and older) and in the different subtypes of dementia. The link between the subtypes of dementia and the presence of particular types of pain (e.g., musculoskeletal pain, neuropathic pain and orofacial pain) will also explored in this study (van Kooten et al., 2015).
These findings have important clinical implications and stress the need for further research to investigate if individuals with dementia are being appropriately treated for pain in terms of the type of analgesic drug, pain intensity, indication, dosage and regimen (Haasum et al., 2011).
Dr Clare S. Allely Lecturer in Psychology. Centre for Health Sciences Research, University of Salford, Salford and affiliate member of the Gillberg Neuropsychiatry Centre, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Benedetti, F., Vighetti, S., Ricco, C., Lagna, E., Bergamasco, B., Pinessi, L., & Rainero, I. (1999). Pain threshold and tolerance in Alzheimer’s disease. Pain, 80(1), 377-382.
Cole, L. J., Farrell, M. J., Duff, E. P., Barber, J. B., Egan, G. F., & Gibson, S. J. (2006). Pain sensitivity and fMRI pain-related brain activity in Alzheimer’s disease. Brain, 129(11), 2957-2965.
Corbett, A., Husebo, B. S., Achterberg, W. P., Aarsland, D., Erdal, A., & Flo, E. (2014). The importance of pain management in older people with dementia. British Medical Bulletin, 111(1), 139-148.
de Medeiros, K., & Black, H. (2015). Suffering and pain in old age In Routledge Handbook of Cultural Gerontology, 181. (Eds.) Julia Twigg, Wendy Martin.
Haasum, Y., Fastbom, J., Fratiglioni, L., Kåreholt, I., & Johnell, K. (2011). Pain treatment in elderly persons with and without dementia. Drugs and Aging, 28(4), 283-293.
Geda, Y. E., Schneider, L. S., Gitlin, L. N., Miller, D. S., Smith, G. S., Bell, J., … & Lyketsos, C. G. (2013). Neuropsychiatric symptoms in Alzheimer’s disease: past progress and anticipation of the future. Alzheimer’s and Dementia, 9(5), 602-608.
Jackson, P. L., Brunet, E., Meltzoff, A. N., & Decety, J. (2006). Empathy examined through the neural mechanisms involved in imagining how I feel versus how you feel pain. Neuropsychologia, 44(5), 752-761.
Morrison, R. S., & Siu, A. L. (2000). A comparison of pain and its treatment in advanced dementia and cognitively intact patients with hip fracture. Journal of Pain and Symptom Management, 19(4), 240-248.
Oosterman, J. M., Hendriks, H., Scott, S., Lord, K., White, N., & Sampson, E. L. (2014). When pain memories are lost: a pilot study of semantic knowledge of pain in dementia. Pain Medicine, 15(5), 751-757.
Parmelee, P. A., Smithy, B., & Katz, I. R. (1993). Pain complaints and cognitive status among elderly institution residents. Journal of the American Geriatrics Society, 41(5), 517-522.
Scherder, E., Bouma, A., Borkent, M., & Rahman, O. (1999). Alzheimer patients report less pain intensity and pain affect than non-demented elderly. Psychiatry, 62(3), 265-272.
Scherder, E. J., Sergeant, J. A., & Swaab, D. F. (2003). Pain processing in dementia and its relation to neuropathology. The Lancet Neurology, 2(11), 677-686.
van Dalen-Kok, A. H., Pieper, M. J., de Waal, M. W., Lukas, A., Husebo, B. S., & Achterberg, W. P. (2015). Association between pain, neuropsychiatric symptoms, and physical function in dementia: a systematic review and meta-analysis. BMC Geriatrics, 15(1), 49.
van Kooten, J., Delwel, S., Binnekade, T. T., Smalbrugge, M., van der Wouden, J. C., Perez, R. S., … & Scherder, E. J. (2015). Pain in dementia: prevalence and associated factors: protocol of a multidisciplinary study. BMC Geriatrics, 15(1), 29.
Warden, V., Hurley, A. C., & Volicer, L. (2003). Development and psychometric evaluation of the Pain Assessment in Advanced Dementia (PAINAD) scale. Journal of the American Medical Directors Association, 4(1), 9-15.
WHO. (2010). International Statistical Classification of Diseases and Related Health Problems 10th Revision. Geneva: WHO; 2010.