Pain
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While cross-sectional studies have demonstrated an association between headache and temporomandibular disorder (TMD), whether headache can predict the onset of TMD is unknown. The aims of this study were to evaluate the contribution of headache to the risk of developing TMD and describe patterns of change in headache types over time. An initially TMD-free cohort of 2410 persons with low frequency of headache completed quarterly questionnaires assessing TMD and headache symptoms over a median 3.0-year follow-up period. ⋯ Patients with TMD were more likely to experience worsening in the headache type compared with that by controls, eg, prevalence of definite migraine among TMD cases increased 10-fold. Among all headache types experienced by patients with TMD before the TMD onset, migraine had the highest odds of progression relative to remission (odds ratio = 2.8, 95% CI: 1.6-4.8), whereas for controls this ratio was significant only for the tension-type headache (odds ratio = 2.1, 95% CI: 1.2-3.9). The important clinical implication of these findings is that adequate treatment of migraine may reduce the risk for developing TMD.
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The upregulation of the tetrodotoxin-resistant voltage-gated sodium channel NaV1.9 has previously been associated with inflammatory hyperalgesia. Na1.9 knockout (KO) mice, however, did not seem insensitive in conventional tests of acute nociception. Using electrophysiological, neurochemical, and behavioral techniques, we now show NaV1.9-null mice exhibit impaired mechanical and thermal sensory capacities and reduced electrical excitability of nociceptors. ⋯ Heat-induced calcitonin gene-related peptide release from the skin was less in the KO than in the WT group. The reduced noxious heat sensitivity was finally confirmed with the Hargreaves test using 2 rates of radiant heating of the plantar hind paws. In conclusion, NaV1.9 presumably contributes to acute thermal and mechanical nociception in mice, most likely through increasing the excitability but probably also by amplifying receptor potentials irrespective of the stimulus modality.
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Randomized Controlled Trial
Long-term outcomes from training in self-management of chronic pain in an elderly population: A randomised controlled trial.
This study compares the outcomes, from pretreatment to 1-year follow-up, of an outpatient, CBT-based pain self-management program (PSM) that included exercises, pain education, and pain coping strategies, with a control condition (exercise-attention control, EAC) that included exercises and a control for the attention of the treatment team. We previously reported short-term results (to 1-month follow-up) from the same study. This new paper considers the important issue of maintenance of treatment-related gains. ⋯ The mean effect size for these gains by the pain self-management program group over the exercise-attention control group was 0.37 (range: 0.29-0.45), which is in the small effect size range. While statistically and clinically meaningful, these findings do indicate some weakening in effects over time but not to a significant degree. The study has implications for the provision of pain management interventions for community-dwelling older adults with chronic pain.