Pain
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Randomized Controlled Trial Comparative Study
The association between negative affect and opioid analgesia in patients with discogenic low back pain.
Comprised mainly of depression, anxiety, and high neuroticism, psychopathology diminishes the effectiveness of many chronic pain treatments. But, it is not known if it is associated with diminished opioid analgesia in patients with chronic, noncancer pain. We tested the hypothesis that psychopathology diminishes opioid analgesia in patients with discogenic low back pain in 60 patients not on opioids in a double blind, placebo controlled, random crossover designed trial. ⋯ A morphine minus placebo analgesia calculation revealed 59.2% TOTPAR in the LOW group vs. 21.7% in the HIGH group, P=.0001. High levels of psychopathology are associated with diminished opioid analgesia in patients with discogenic low back pain. These results have implications for the prescription of oral opioids to patients with chronic low back pain and psychopathology.
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Comparative Study
Trigeminal P2X3 receptor expression differs from dorsal root ganglion and is modulated by deep tissue inflammation.
The distribution and modulation of the P2X(3) receptor was studied in trigeminal ganglion neurons to provide insight into the role of ATP in craniofacial sensory mechanisms. Binding to the d-galactose specific lectin IB4 was found in 73% of P2X(3)-positive neurons while only 16% of IB4 neurons expressed P2X(3). Neurons expressing P2X(3) alone were significantly larger than IB4-or IB4/P2X(3)-positive neurons. ⋯ These results indicate that within trigeminal ganglia: (1) the P2X(3) receptor is expressed in both small and medium-sized neurons; (2) the P2X(3) receptor is not exclusively expressed in IB4 neurons; (3) P2X(3) is co-expressed with neuropeptides; (4) differences in the proportion of cutaneous versus muscle P2X(3) afferents are not apparent. Trigeminal P2X(3) neurons therefore differ markedly from dorsal root ganglion P2X(3) afferents. This study also shows that deep tissue inflammation modulates expression of the P2X(3) receptor and thus may warrant exploration as a target for therapeutic intervention.
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Comparative Study
Neurophysiologic and quantitative sensory testing in the diagnosis of trigeminal neuropathy and neuropathic pain.
This study investigated the utility of neurophysiologic examination and thermal quantitative sensory testing (QST) in the diagnosis of trigeminal neuropathy and neuropathic pain. Fifty-eight patients (14 men), 34 with sensory deficit within the inferior alveolar nerve (IAN) and 24 within the lingual nerve (LN) distribution, were included. Twenty-six patients (45%) reported neuropathic pain. ⋯ It was associated with the occurrence of neuropathic pain (P=0.016). Axonal Abeta afferent damage was less severe in the IAN patients with pain than in those without pain (P=0.012). Neurophysiologic tests and thermal QST provide sensitive tools for accurate diagnosis of trigeminal neuropathy and study of pathophysiological features characteristic to human neuropathic pain.
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Randomized Controlled Trial Comparative Study
Brief cognitive-behavioral therapy for temporomandibular disorder pain: effects on daily electronic outcome and process measures.
We used patient daily electronic ratings of outcome (activity interference, pain intensity, jaw use limitations, negative mood) and process (pain-related beliefs, catastrophizing, and coping) variables to evaluate a brief cognitive-behavioral (CB) treatment for chronic temporomandibular disorder (TMD) pain. TMD clinic patients (N=158) were assigned randomly to four biweekly sessions of either CB pain management training (PMT) or an education/attention control condition [self-care management (SCM)] and were asked to complete electronic interviews three times daily for the 8-week treatment. We analyzed diary data from 126 participants who completed >50% of requested interviews for >6 weeks. ⋯ This study is novel in its application of electronic diary methods for assessing outcome and process variables in a chronic pain treatment trial, and supports the feasibility and utility of such methods. The brief CB treatment was efficacious in decreasing catastrophizing and increasing perceived control over pain, and in improving activity interference and jaw use limitations for a subgroup of patients. Longer-term follow-ups are ongoing to determine if there is an impact on outcomes over time.
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Comparative Study
Ambivalence over emotional expression in patients with gastrointestinal cancer and their caregivers: associations with patient pain and quality of life.
This study examined the role of patient and caregiver ambivalence over emotional expression (AEE) in pain and quality of life (QOL) in a sample of 78 patients with gastrointestinal (GI) cancer. Measures of ambivalence over emotional expression as well as ratings of patient pain and pain behavior were collected from patients and caregivers. Measures of pain catastrophizing, perceptions of social support, and QOL were obtained from patients. ⋯ In addition, patients whose caregivers were high in AEE engaged in more catastrophizing, had higher levels of pain and pain behavior, and reported lower emotional well-being. Patient catastrophizing mediated the effects of both patient and caregiver AEE on some patient outcomes. Taken together, these findings suggest that emotional regulation in both patients and their caregivers may be an important factor in understanding cancer patients' experience of and coping with symptoms such as pain.