Pain
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Pain perception and autonomic responses to pain are known to be altered in dementia, although the mechanisms are poorly understood. We studied patients with Alzheimer's disease (AD) whose cognitive status was assessed through the Mini Mental State Examination test and whose brain electrical activity was measured by means of quantitative electroencephalography. After assessment of both cognitive impairment and brain electrical activity deterioration, these patients underwent sensory measurements in which the minimum stimulus intensity for both stimulus detection and pain sensation was determined. ⋯ These results indicate that pain anticipation and reactivity depend on both the cognitive status and the frequency bands of the electroencephalogram, whereas both stimulus detection and pain threshold are not affected by the progression of AD. These findings indicate that, whereas the sensory-discriminative components of pain are preserved even in advanced stages of AD, the cognitive and affective functions, which are related to both anticipation and autonomic reactivity, are severely affected. This sensory-affective dissociation is well correlated with the neuropathological findings in AD.
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This study describes suicidal behavior in a cross-sectional sample of chronic pain patients and evaluates factors associated with increased risk for suicidal ideation. One hundred-fifty-three adults with nonmalignant pain (42% back pain) who were consecutively referred to a tertiary care pain center completed a Structured Clinical Interview for Suicide History, the McGill Pain Questionnaire, and the Beck Depression Inventory. Nineteen-percent reported current passive suicidal ideation (PSI), 13% had active thoughts of committing suicide (ASI), 5% had a current suicide plan, and 5% reported a previous suicide attempt. ⋯ Neuropathic pain significantly reduced risk for both PSI (P=0.002) and ASI (P=0.01). Demographics, pain severity, and depression severity were not associated with suicidal ideation in multivariate analyses. These findings highlight the need for routine evaluation and monitoring of suicidal behavior in chronic pain, especially for patients with family histories of suicide, those taking potentially lethal medications, and patients with abdominal pain.
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Little is known about the relationship between chronic pain status and overall use of healthcare. We examined whether disabling chronic pain was associated with more frequent use of healthcare in three settings: primary care, emergency departments, and hospital admissions. We used data from Computer-Assisted Telephone Interviews (CATI) of 17,543 residents in New South Wales, Australia aged 16 and over who were randomly sampled using a population-based two-stage stratified sample and random digit dialing methods. ⋯ There was a strong association between pain-related disability and greater use of services. Further work is needed to understand the nature of this association. Given the fluctuating course of chronic pain over time, there is a significant segment of the population that may be at risk of developing higher levels of disability associated with increased use of services.
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Comparative Study
Rapid deterioration of pain sensory-discriminative information in short-term memory.
The assessment of pain and analgesic efficacy sometimes relies on the retrospective evaluation of pain felt in the immediate, recent or distant past, yet we have a very limited understanding of the processes involved in the encoding, maintenance and intentional retrieval of pain. We examine the properties of the short-term memory of thermal and pain sensation intensity with a delayed-discrimination task using pairs of heat pain, warm and cool stimulation in healthy volunteers. Performance decreased as a function of the inter-stimulus interval (ISI), indicating a robust deterioration of sensory information over the test period of 4-14 s. ⋯ Importantly, performance declined steadily with increasing ISI (from 6 to 14 s)--but only for pairs of heat pain stimuli that were relatively difficult to discriminate (Delta-T < or = 1.0 degree C; perceptual difference < or = 32/100 pain rating units) while no deterioration in performance was observed for the largest temperature difference tested (Delta T = 1.5 degrees C; perceptual difference of 50 units). These results are consistent with the possibility that short-term memory for pain and temperature sensation intensity relies on a transient analog representation that is quickly degraded and transformed into a more resistant but less precise categorical format. This implies that retrospective pain ratings obtained even after very short delays may be rather inaccurate but relatively reliable.
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This study continued the validation of a Whiplash Specific Disability Questionnaire (WDQ) that was developed from the Neck Disability Index (NDI) using self-reported disabilities in a group of participants experiencing whiplash-associated disorders [J Manipulative Physiol Ther 14 (1991) 409]. Previous research has established the content, construct and face validity and internal consistency of the WDQ. The aim of this study was to establish the short-term and medium-term test-retest reliability and responsiveness of the WDQ. ⋯ Correlation between change in WDQ score over 1 month and participant perceived change was r(s) = 0.64, the effect size was 0.03, the SRM was 0.08 and the responsiveness statistics were 0.90 (participants who improved) and -1.60 (participants who deteriorated). The minimal detectable change of the WDQ was established at 15 points. These results demonstrate that the WDQ has excellent short- and medium-term reproducibility and responsiveness in a population seeking treatment for WAD.