Neuroscience
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Controlled Clinical Trial
Inhibition of pain and pain-related brain activity by heterotopic noxious counter-stimulation and selective attention in chronic non-specific low back pain.
The aim of the present study was to assess inhibition of pain and somatosensory-evoked potentials (SEPs) by heterotopic noxious counter-stimulation (HNCS) and by selective attention in patients with chronic non-specific LBP. Seventeen patients and age/sex-matched controls were recruited (10 men, 7 women; mean age ± SD: 43.3 ± 10.4 and 42.7 ± 11.1, respectively). On average, patients with LBP reported pain duration of 7.6 ± 6.5 years, light to moderate disability (19.3 ± 5.7/100) and low clinical pain intensity (21.8 ± 1.5/100), while pain catastrophizing, state and trait anxiety and depressive symptoms were not significantly different between groups (all p's >0.05). ⋯ This indicates that patients with the characteristics described above do not show altered pain inhibitory mechanisms involved in HNCS and selective attention. Importantly, this experiment was carefully designed to control for non-specific effects associated with the repetition of the test stimulus and the effect of an innocuous counter-stimulation. It remains to be determined if these results hold for patients with severe LBP and psychological symptoms or whether symptom severity may be associated with pain inhibition deficits.
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Advances in pediatric cancer treatment have led to a ten year survival rate greater than 75%. Platinum-based chemotherapies (e.g. cisplatin) induce peripheral sensory neuropathy in adult and pediatric cancer patients. The period from birth through to adulthood represents a period of maturation within nociceptive systems. ⋯ The percentage of IB4+ve, CGRP+ve and NF200+ve DRG neurons was not different between groups at P45. There was an increase in TrkA+ve DRG neurons in the cisplatin group at P45, in addition to increased TrkA, NF200 and vGLUT2 immunoreactivity in the lumbar dorsal horn versus controls. These data highlight the impact pediatric cancer chemotherapy has upon the maturation of pain pathways and later life pain experience.
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Clinical Trial
The role of sex in sleep deprivation related changes of nociception and conditioned pain modulation.
Sex matters both in the clinical field of pain and sleep medicine. Sleep disturbances are highly prevalent in chronic pain patients and have been shown to deteriorate the pain condition. The pathomechanisms by which insomnia aggravates pain are currently unknown. ⋯ While TSD-induced cold and mechanical hyperalgesia were independent of sex, heat pain thresholds did only significantly decrease in sleep deprived females (p = 0.041). Our results point to a sex specific impact of TSD on descending pain inhibition. In the future, therapeutic strategies for pain patients with co-morbid insomnia may need to more explicitly respect the specific role of sex.
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This study aimed to investigate the relation of GABA and glutamate levels in the posterior insula and mechanical pain sensitivity in healthy subjects. Nineteen healthy female individuals underwent single voxel magnetic resonance spectroscopy (MRS) at 3 T. Metabolites were measured in the right posterior insula using MEGA-PRESS spectral editing. ⋯ No significant correlation for pinprick stimuli of lower forces than 256 mN was observed. The results of our study support the hypothesis that excitatory and inhibitory neurotransmitter levels and/or the ratio of glutamate/GABA levels in the posterior insula are related to individual differences in pain sensitivity. These results are in line with chronic pain studies, where elevated glutamate/GABA ratios in the insular cortex of patients with chronic pain syndromes were observed.
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Chronic low back pain (CLBP) is challenging to treat. Minimal invasive neurostimulation therapies, such as subcutaneous peripheral nerve field stimulation (SPNS), improve pain relief and quality of life. The goal of the present study was to assess the usefulness, safety, and efficacy of SPNS in patients with CLBP. ⋯ The complication rate was 23% (3/13 patients). In non-responders, VAS and ODI at 24 months dropped significantly as well but the decrease was less pronounced compared to responders and had not led to a decrease in pain medication. SPNS is a novel, safe, and effective treatment for CLBP and may have advantages over interventional treatments including intrathecal therapy and spinal cord stimulation.