Year: 2005-06 (current)

Staff:  Steve Gibson, Bruce Barber, Pam Johnson (PhD Student)

Summary: Growing international concern exists over the adequacy of pain assessment in older adults with cognitive impairment or communication problems. Our current understanding of the pain experience in these patients remains largely unexplored. A three-year NHMRC-funded research program aims to:
. Examine the utility, reliability and validity of several different pain assessment techniques;
. Determine the extent to which measures of pain vary as a function of cognitive status;
. Explore differences in non-verbal indictors of acute and chronic pain; and
. Develop a multivariate algorithm for predicting pain in non-verbal older adults.

Preliminary results show that introducing a movement-based protocol during the pain assessment period appears to improve the sensitivity and specificity of the observational methods. Physiological measures of painful disease and signs and symptoms of hyperalgesia are somewhat limited in discriminating chronic pain states. However, these may be useful for acute pain assessment in non-verbal populations. Work is continuing on developing an appropriate video sequence to capture older people’s facial expressions of pain when they are moving.

Funding source: NHMRC

Year: 2005-06 (current)

Staff:  Steve Gibson, Leonie Carabott (PhD Student)

Summary: This study examined pain sensitivity and supraspinal pain processing in fourteen people with Alzheimer’s Disease (AD) and the same number of age-matched healthy volunteers. Experimentally controlled pressure stimuli were delivered to the thumbnail of the right hand to determine thresholds for just noticeable pain, weak pain and moderate pain. In a subsequent session, functional magnetic resonance (fMRI) images were collected during these three levels of pressure stimulation that were presented in 30-second blocks, interspaced with 24-second no-stimulus periods. The mean stimulus intensities required to elicit reports of just noticeable, mild and moderate pain were higher for the AD group compared with controls. The fMRI data revealed a common network of pain-related activity, with both groups showing activation in the superior and middle frontal gyri, pre-central gyrus, inferior parietal lobule, lentiform nucleus, dorsomedial thalamus, insula, and posterior cerebellum during noxious versus innocuous stimulation. AD patients showed significant activity in several components of the medial pain pathway during noxious versus pressure stimulation and when compared with the controls, the AD patients had significantly greater activation in the contralateral inferior frontal gyrus and anterior cingulate regions.

The greater activation seems to result from a much more prolonged cortical response to pain in the medial pain pathways in the AD group. While AD patients showed heightened pain thresholds, the pattern of pain-related brain activity observed with fMRI suggests that the central processing of nociceptive information is not impaired in AD, therefore, raising concerns about the under-treatment of pain in this highly dependent and vulnerable group.

Funding source: NHMRC

Summary: This recently completed 3 year research program sought to examine a large sample of community dwelling older persons of varying cognitive status in order to determine the extent to which dementia might alter the pain experience and the emotional/functional impact of persistent pain. Part of the sample for this study included selected patients from the NARI/MECRS pain clinic for older persons.

Funding source: City of Kingston