Pain
-
Repeated exposure to pain can result in sensitization of the central nervous system, enhancing subsequent pain and potentially leading to chronicity. The ability to reverse this sensitization in a top-down manner would be of tremendous clinical benefit, but the degree that this can be accomplished volitionally remains unknown. Here we investigated whether a brief (~5 min) cognitive-behavioural intervention could modify pain perception and reduce central sensitization (as reflected by secondary hyperalgesia). ⋯ Furthermore, secondary hyperalgesia was significantly reduced in the regulate group compared with the control group. Reduction in secondary hyperalgesia was associated with reduced pain catastrophizing, suggesting that changes in central sensitization are related to changes in pain-related cognitions. Thus, we demonstrate that central sensitization can be modified volitionally by altering pain-related thoughts.
-
Randomized Controlled Trial
The association of acetazolamide infusion with headache and cranial artery dilation in healthy volunteers.
The carbonic anhydrase inhibitor acetazolamide causes extracellular acidosis and dilatation of cerebral arterioles. In this study, we tested the hypothesis that acetazolamide also may induce headache and dilatation of cranial arteries. In a randomized double-blind crossover study design, 12 young healthy women were allocated to injection of 1 g acetazolamide or placebo on 2 separate days. ⋯ Compared to placebo, arterial circumference increased after acetazolamide in the basilar artery (P=.002) as well as the cerebral (P=.003), cavernous (P=.002), and cervical (P=.005) parts of the internal carotid artery, but no other extracranial arteries changed after acetazolamide. In conclusion, acetazolamide caused immediate and delayed headache as well as dilatation of intracranial arteries in healthy volunteers. It is possible that extracellular acidosis induced by acetazolamide causes sensitization of cephalic perivascular nociceptors, which, in combination with vasodilatation, leads to delayed headache.
-
Randomized Controlled Trial
Short-term Improvement in Insomnia Symptoms Predicts Long-term Improvements in Sleep, Pain, and Fatigue in Older Adults with Co-Morbid Osteoarthritis and Insomnia.
In a primary care population of 367 older adults (aged ⩾60 years) with osteoarthritis (OA) pain and insomnia, we examined the relationship between short-term improvement in sleep and long-term sleep, pain, and fatigue outcomes through secondary analyses of randomized controlled trial data. Study participants, regardless of experimental treatment received, were classified either as improvers (⩾30% baseline to 2-month reduction on the Insomnia Severity Index [ISI]) or as nonimprovers. After controlling for treatment arm and potential confounders, improvers showed significant, sustained improvements across 18 months compared with nonimprovers in pain severity (P<0.001, adjusted mean difference=-0.51 [95% CI: -0.80, -0.21), arthritis symptoms (P<0.001, 0.63 [0.26, 1.00]), and fear avoidance (P=0.009, -2.27 [-3.95, -0.58]) but not in catastrophizing or depression. Improvers also showed significant, sustained improvements in ISI (P<0.001, -3.03 [-3.74, -2.32]), Pittsburgh Sleep Quality Index Total (P<0.001, -1.45 [-1.97, -0.93]) and general sleep quality (P<0.001, -0.28 [-0.39, -0.16]) scores, Flinders Fatigue Scale (P<0.001, -1.99 [-3.01, -0.98]), and Dysfunctional Beliefs About Sleep Scale (P=0.037, -2.44 [-4.74, -0.15]), but no improvements on the Functional Outcomes of Sleep Questionnaire or the Epworth Sleepiness Scale. We conclude that short-term (2-month) improvements in sleep predicted long-term (9- and 18-month) improvements for multiple measures of sleep, chronic pain, and fatigue. These improvements were not attributable to nonspecific benefits for psychological well-being, such as reduced depression. These findings are consistent with benefits of improved sleep for chronic pain and fatigue among older persons with osteoarthritis pain and comorbid insomnia if robust improvements in sleep are achieved and sustained.