Pain
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One approach to the study of disordered spatial attention is to carry out tests of extinction, in which stimuli are detected on the left when they are presented on the left alone, but not when both sides are stimulated simultaneously in a dual simultaneous stimulation (DSS) protocol. Extinction has been documented for multiple sensory modalities, but not for thermal pain stimuli, to our knowledge. We now test the hypothesis that subjects with visual spatial neglect (hemi-neglect) will have alterations in thermal pain sensation which are related to abnormal spatial attention. ⋯ Ratios indicating the magnitude of extinction, mislocalization and misidentification were significantly larger on the left side of subjects with visual spatial neglect than in healthy controls or in controls with stroke but without hemineglect. The proportion of subjects with thermal pain extinction, mislocalization, or misidentification was significantly higher in subjects with hemi-neglect than those in either control group. These results demonstrate that disordered attention exerts a powerful effect upon the perception of both the location and the quality of thermal pain stimuli.
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This study mapped the fine-scale functional representation of tactile and noxious heat stimuli in cortical areas around the central sulcus of anesthetized squirrel monkeys by using high-resolution blood oxygen level-dependent (BOLD) fMRI at 9.4T. Noxious heat (47.5°C) stimulation of digits evoked multiple spatially distinct and focal BOLD activations. Consistent activations were observed in areas 3a, 3b, 1, and 2, whereas less frequent activation was present in M1. ⋯ Differential BOLD response profiles of the individual cortical areas along the central sulcus suggest that these areas play different roles in the encoding of nociceptive inputs. Thermal nociceptive and tactile inputs may be processed by different clusters of neurons in different areas. To critically bridge animal and human pain studies, human fMRI was related to primate fMRI and electrophysiology of nociceptive processing, examining the functional role of the primary somatosensory cortex in heat nociception and demonstrating that subregion areas 3a, 3b, 1, 2, and M1 are responsive to noxious heat stimuli.
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Central pain syndromes associated with damage to the thalamic sensory relay nuclei have been described predominantly in the stroke literature; however, pain syndromes associated with thalamic neoplasms are much less common. We describe a woman with dyspareunia secondary to vaginal allodynia as the presenting sign of a left thalamic juvenile pilocytic astrocytoma. ⋯ We believe that this is the first reported case of isolated vaginal allodynia associated with a thalamic neoplasm or any other structural pathology of the central nervous system. Dyspareunia secondary to vaginal allodynia as the presenting sign of a left thalamic juvenile pilocytic astrocytoma is reported, in a rare case underscoring that thalamic pathology including neoplasms should be considered in evaluating patients with longstanding and unexplained pain syndromes.
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The objective of this study was to investigate the national pattern of strong opioid use among community-dwelling persons with and without Alzheimer's disease (AD) in Finland. All persons (n=28,093) with a diagnosis of AD in 2005 were identified by the Social Insurance Institution of Finland (SII). For each person with AD, the SII identified a comparison person individually matched in terms of age (±1year), sex, and region of residence. ⋯ However, the results highlight the challenges associated with diagnosing and treating pain in this population, and the importance of balancing the risk of adverse drug reactions against the ease of transdermal administration. Use of opioid analgesics was lower among 28,089 persons with Alzheimer's disease (AD) compared with individually matched comparison persons without AD. However, use of strong opioids and transdermal fentanyl was more prevalent among persons with AD.