Pain
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Clinical Trial
On the repeatability of brush-evoked allodynia using a novel semi-quantitative method in patients with peripheral neuropathic pain.
Using a semi-quantitative method the repeatability of brush-evoked allodynia was examined within and between days in nine patients with spontaneous ongoing pain and dynamic mechanical allodynia due to peripheral neuropathy. In addition, the relationship between the intensity of spontaneous ongoing pain and the total brush-evoked pain intensity was addressed. The brush stimulus was applied in the innervation territory of the lesioned nervous structure by lightly stroking 60 mm of the skin four times with an 8 mm wide brush. ⋯ The patients were examined 4 days during one month, i.e. at day 1, 3, 28 and 30 and each study day the stimulus was repeated four times with an inter-stimulus interval of 10 min. The variation between repeated assessments was analyzed using the intraclass correlation coefficient and the total brush-evoked pain intensity within days ranged from 0.89 to 0.95 ("very good repeatability") and between days from 0.77 to 0.97 ("very good repeatability"). A significant positive correlation was demonstrated between the mean intensity of spontaneous ongoing pain and the mean total brush-evoked pain intensity (r(s)=0.68, P<0.042, "a moderate to good correlation").
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Depression is a common feature of chronic pain, but there is only limited research into the content of depressed cognitions in pain patients. This study investigated the content of cognition in depressed pain patients, non-depressed pain patients, and two control groups, healthy controls, and osteopaths using a sentence completion task. Participants generated completed sentences to a set of predefined stems that included negative, positive and neutral self-reference, and past, future and world terms. ⋯ We suggest that the focus of depression in chronic pain patients is health related. Pain patients who are not depressed focus on health, but not necessarily in a negative way. The concept of themselves in the future might be a key aspect in depression in pain patients.
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Randomized Controlled Trial
Botulinum toxin type A reduces capsaicin-evoked pain and neurogenic vasodilatation in human skin.
The effect of Botulinum Toxin type A (BoNT/A) on pain and neurogenic vasodilatation induced by application to the human skin of thermal stimuli and capsaicin was evaluated in a double blind study. A capsaicin cream (0.5 ml of a 0.075%) was applied to the skin of both forearms of eighteen subjects randomly pretreated with either BoNT/A (Botox) or 0.9% saline (NS). Capsaicin was applied to a skin area either inside (protocol A) or adjacent to the BoNT/A treated area (protocol B). ⋯ In Protocol B, capsaicin-induced pain was unchanged, and capsaicin-induced flare/increase in CBF were reduced only in the area treated with BoNT/A, but not in the BoNT/A untreated area. Results indicate that (i) BoNT/A reduces capsaicin-induced pain and neurogenic vasodilatation without affecting the transmission of thermal and thermal-pain modalities; (ii) reduction in capsaicin-induced pain occurs only if capsaicin is administered into the BoNT/A pretreated area; (iii) reduction in neurogenic vasodilatation by BoNT/A does not contribute to its analgesic action. BoNT/A could be tested for the treatment of conditions characterised by neurogenic inflammation and inflammatory pain.
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Clinicians recognize the importance of monitoring aberrant medication-related behaviors of chronic pain patients while being prescribed opioid therapy. The purpose of this study was to develop and validate the Current Opioid Misuse Measure (COMM) for those pain patients already on long-term opioid therapy. An initial pool of 177 items was developed with input from 26 pain management and addiction specialists. ⋯ To evaluate the COMM's ability to capture change in patient status, it was tested on a subset of patients (N=86) that were followed and reassessed three months later. The COMM was found to have promise as a brief, self-report measure of current aberrant drug-related behavior. Further cross-validation and replication of these preliminary results is pending.