Stephen J. Gibson

An interdisciplinary expert consensus statement on assessment of pain in older persons

This paper represents an expert-based consensus statement on pain assessment among older adults. It is intended to provide recommendations that will be useful for both researchers and clinicians. Contributors were identified based on literature prominence and with the aim of achieving a broad representation of disciplines. Recommendations are provided regarding the physical examination and the assessment of pain using self-report and observational methods (suitable for seniors with dementia). In addition, recommendations are provided regarding the assessment of the physical and emotional functioning of older adults experiencing pain. The literature underlying the consensus recommendations is reviewed. Multiple revisions led to final reviews of 2 complete drafts before consensus was reached.

The epidemiology of pain in elderly people

Acute pain probably occurs at much the same rate across all age groups. On the other hand, self-report of chronic pain seems to increase up to, but not beyond, the seventh decade of life. Chronic pain in older people is more often experienced in major joints, the back, legs and feet, whereas visceral pain and headache are reported less often. There is a divergence between an increasing load of pain-associated disease and a plateau of chronic pain complaint in old age that probably reflects impairment in the nociceptive function of the nervous system. However, the contribution of social, behavioral, cognitive, and affective dimensions of the pain experience to this divergence between disease and pain have not been fully evaluated. Most of the answers to these and other questions require longitudinal studies with pain as the predominant focus of attention rather than addressing the symptom of pain as an ancillary measure relevant to other aspects of aging.

Age-related differences in pain perception and report

The clinical and laboratory-based evidence for age-related differences in pain perception and report are reviewed. Most clinical studies suggest a relative decrease in the frequency and intensity of pain symptoms associated with myocardial complaints, visceral infections, musculoskeletal conditions, and postoperative and malignant pain problems in adults of advanced age. The findings from experimentally controlled laboratory investigations are more equivocal and vary according to the type and intensity of noxious stimulation. Nonetheless, such studies also provide some additional support for the notion of an age-related decrease in pain perception and report. Evidence has not determined whether the observed changes are caused by the aging process or reflect other age-associated effects, including an increased presence of comorbid disease, biocultural cohort effects, or altered psychosocial influences.

Altered heat pain thresholds and cerebral event-related potentials following painful CO2 laser stimulation in subjects with fibromyalgia syndrome

&NA; A decrease in mechanical pressure pain thresholds, particularly over pre‐designated tender points, is one of the defining characteristics of fibromyalgia syndrome (FS); however, changes in thermal pain sensitivity have not been investigated. The present study examined heat pain thresholds and cerebral event‐related potentials following CO2 laser stimulation in 10 subjects with FS and 10 age‐matched control volunteers. The results indicate that patients with FS exhibit a significant reduction in heat pain threshold when tested on the dorsal surface of the hand. In accordance with previous research, we also found a decrease in mechanical pain threshold over pre‐designated tender points and at control sites as well as a significantly larger mechanically induced neurogenic flare response. These measures were highly correlated with thermal pain threshold even though different anatomical sites were stimulated. Hence, it seems likely that FS patients display a multimodal change in pain sensitivity which is generalized rather than anatomically restricted. Patients with FS also displayed a significant increase in the peak‐to‐peak amplitude of the cerebral potential evoked by CO2 laser stimulation at pain threshold intensity and 1.5 times pain threshold intensity. These findings suggest a greater activation of central nervous system (CNS) pathways following noxious input. Putative explanations for the increased CNS response are discussed, including mechanisms of peripheral nociceptor sensitization, altered CNS function and the role of psychological factors.

A review of age differences in the neurophysiology of nociception and the perceptual experience of pain.

Objective:To better understand the nature of age differences in pain and nociception with the aging of the worlds’ population. Methods:The evidence from numerous neurophysiologic and psychological studies suggest a small, but demonstrable age-related impairment in the early warning functions of pain. The increase in pain perception threshold and the widespread change in the structure and function of peripheral and CNS nociceptive pathways may place the older person at greater risk of injury. Moreover, the reduced efficacy of endogenous analgesic systems, a decreased tolerance of pain and the slower resolution of postinjury hyperalgesia may make it more difficult for the older adult to cope, once injury has occurred. Results:These age-related changes may be best conceptualized as a reduced capacity in the functional reserve of the pain system, at both ends of the intensity spectrum. Discussion:The clinical implications are obvious; older persons are likely to be especially vulnerable to the negative impacts of pain and pain associated events.

Age-related differences in the endogenous analgesic response to repeated cold water immersion in human volunteers.

&NA; Recent animal studies using stress‐induced analgesia have suggested a general age‐related decline in endogenous pain inhibitory systems. The aim of the current study was to examine age‐related differences in the magnitude of endogenous analgesia in human volunteers, using psychophysical measures of neuroselective electrical, and thermal CO2 laser induced pain thresholds, before, immediately after and 1 h after repeated cold water immersion of the hand. Sensory detection thresholds did not differ between age groups indicating that the functional integrity of primary afferent sensory fibres appears to be intact in older people. Consistent with many previous studies, older adults required a higher intensity of noxious stimulation in order to first report the presence of pain. The cold water immersion task was effective in eliciting a powerful analgesic response, regardless of age; pain thresholds were shown to increase by up to 100% immediately after the cold pressor test. This effect was relatively transient with thresholds returning to baseline within 1 h. The magnitude of analgesic response, however, was found to be significantly less in older people. Age differences in the efficacy of endogenous analgesic systems may be expected to reduce the ability of older adults to cope with severe persistent pain states and may help explain some of the variation in the literature on pain report.

The effect of age on Aδ- and C-fibre thermal pain perception

&NA; It has been suggested that ageing may have a differential effect on C fibre‐mediated protopathic/tonic pain versus epicritic/phasic pain perception mediated by A&dgr; fibres. The present study attempted to independently assess age‐related changes in the function of A&dgr;‐ and C‐nociceptive fibres by examining CO2 laser‐induced thermal pain thresholds before, during and after a compression block of the superficial radial nerve in 15 young and 15 healthy elderly adult subjects. Nerve block efficacy was monitored via measures of cold, warm and mechanical threshold, and simple reaction time. During nerve compression block, reaction time and mechanical threshold increased, cold sensation became impaired while warm sensation remained unaffected throughout the test in both groups. With respect to pain sensitivity, young adults exhibited significant increases in thermal pain threshold during A‐fibre block while pain threshold remained relatively stable across the 3 test periods in the elderly group. It would appear that elderly adults rely predominantly on C‐fibre input when reporting pain whereas younger adults utilise additional input from A&dgr; fibres. Subsequent analysis revealed that during pre‐ and post‐block periods, older adults exhibited a significant elevation in thermal pain threshold; however, when A&dgr;‐fibre function was impaired and only C‐fibre information was available, both groups responded similarly. These findings support the notion of a differential age‐related change in A‐fibre‐mediated epicritic pain perception versus C‐fibre‐mediated protopathic pain.

Pain in older persons

Chronic pain is more prevalent in older persons than in young adults. In this review the physiological, pathological, and psychological reasons for altered pain sensibility in older persons are explored and strategies for the management of pain in older persons described. The evidence suggests that altered physiology of peripheral and central pain mechanisms combine with psychological attitudes, such as stoicism and reluctance to confirm the presence of pain, to raise pain threshold. However, once pain is experienced, older persons describe the same severity, quality, and psychological disturbance as younger persons. There is some evidence to suggest that the complaint of pain in the presence of pathology is reported less often in older persons. On the other hand, the presence of persistent or recurrent clinical pain may have a greater impact on the psychological, social, and physical function of older adults. It is also clear, however, that further empirical studies are required in order to delineate the...

Pain in Dementia

The ageing revolution is changing the composition of our society with more people becoming very old with higher risks for developing both pain and dementia. Pain is normally signaled by verbal communication, which becomes more and more deteriorated in people with dementia. Thus, these individuals unnecessarily suffer from manageable but unrecognized pain. Pain assessment in patients with dementia is a challenging endeavor, with scientific advancements quickly developing. Pain assessment tools and protocols (mainly observational scales) have been incorporated into national and international guidelines of pain assessment in aged individuals. To effectively assess pain, interdisciplinary collaboration (nurses, physicians, psychologists, computer scientists, and engineers) is essential. Pain management in this vulnerable population is also preferably done in an interdisciplinary setting. Nonpharmacological management programs have been predominantly tested in younger populations without dementia. However, many of them are relatively safe, have proven their efficacy, and therefore deserve a first place in pain management programs. Paracetamol is a relatively safe and effective first-choice analgesic. There are many safety issues regarding nonsteroidal anti-inflammatory drugs, opioids, and adjuvant analgesics in dementia patients. It is therefore recommended to monitor both pain and potential side effects regularly. More research is necessary to provide better guidance for pain management in dementia.

Clinical pharmacology of analgesic medicines in older people: impact of frailty and cognitive impairment

Pain is highly prevalent in frail older people who often have multiple co-morbidities and multiple medicines. Rational prescribing of analgesics in frail older people is complex due to heterogeneity in drug disposition, comorbid medical conditions, polypharmacy and variability in analgesic response in this population. A critical issue in managing older people with pain is the need for judicious choice of analgesics based on a comprehensive medical and medication history. Care is needed in the selection of analgesic medicine to avoid drug-drug or drug-disease interactions. People living with dementia and cognitive impairment have suboptimal pain relief which in part may be related to altered pharmacodynamics of analgesics and challenges in the systematic assessment of pain intensity in this patient group. In the absence of rigorously controlled trials in frail older people and those with cognitive impairment a pharmacologically-guided approach can be used to optimize pain management which requires a systematic understanding of the pharmacokinetics and pharmacodynamics of analgesics in frail older people with or without changes in cognition.