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Knee arthroplasty (KA) is an effective surgical procedure. However, clinical studies suggest that a considerable number of patients continue to experience substantial pain and functional loss following surgical recovery. We aimed to estimate pain and function outcome trajectory types for persons undergoing KA, and to determine the relationship between pain and function trajectory types, and pre-surgery predictors of trajectory types.
Learn More >Pain impacts the lives of millions of community-dwelling older adults. An important characteristic of pain is "pain interference" which describes the influence of pain on function. A description of pain interference is limited in rural settings where the number of older adults is expected to increase, and health disparities exist.
Learn More >Chronic pain patients are frequent and recurrent users of health services, which may have an impact on levels of health literacy (HL). Therefore, the aim of the present study was to investigate associations between healthcare utilization and varying levels of HL in individuals with and without chronic pain.
Learn More >Chronic neuropathic pain is known to alter the primary motor cortex (M1) function. Less is known about the normal, physiological effects of experimental neurogenic pain on M1. The objective of this study is to determine how short-interval intracortical inhibition (SICI) is altered in the M1 representation area of a muscle exposed to experimental pain compared to SICI of another muscle not exposed to pain. The cortical representation areas of the right abductor pollicis brevis (APB) and biceps brachii (BB) muscles of 11 subjects were stimulated with a multi-locus transcranial magnetic stimulation device while the resulting motor-evoked potentials (MEPs) were recorded with electromyography. Single- and paired-pulse TMS was administered in seven conditions, including one with the right hand placed in cold water. The stimulation intensity for the conditioning pulses in the paired-pulse examination was 80% of the resting motor threshold (RMT) of the stimulated site and 120% of RMT for both the test and single pulses. The paired-pulse MEP amplitudes were normalized with the mean amplitude of the single-pulse MEPs of the same condition and muscle. SICI was compared between conditions. After the cold pain, the normalized paired-pulse MEP amplitudes decreased in APB, but not in BB, indicating that SICI was potentially increased only in the cortical area of the muscle subjected to pain. These data suggest that SICI is increased in the M1 representation area of a hand muscle shortly after exposure to pain has ended, which implies that short-lasting pain can alter the inhibitory balance in M1.
Learn More >Evidence is accumulating that activation of mineralocorticoid (MR) and glucocorticoid (GR) receptors on peripheral sensory neurons modulates pain sensation. While the expression and exact anatomical localization of MR and GR in the various subpopulations of peripheral sensory neurons has been shown in animals, it is still unknown for the human skin. Therefore, we aimed to identify MR and GR mRNA and protein as well as the exact subpopulations of sensory neurons in human versus rat skin. Tissue samples from rat and human skin were subjected to RT-PCR, Western blot and double immunofluorescence confocal analysis of MR and GR with the neuronal markers calcitonin gene-related peptide (CGRP), neurofilament 200 (NF200) and tyrosine hydroxylase (TH). Using RT-PCR we were able to isolate MR as well as GR specific transcripts from human skin. Consistently, Western blot analysis identified MR- as well as GR- specific protein bands at the expected molecular weights of 110 and 87 kD, respectively. Double immunofluorescence confocal microscopy of human skin revealed that MR predominantly colocalized with calcitonin-gene-related peptide (CGRP)-immunoreactive (IR) nociceptive neurons – similar to rat skin – underscoring a pivotal role for MR in the modulation of pain. The majority of GR-immmunoreactivity was localized in peripheral peptidergic CGRP-IR sensory nerve fibers, but in addition on TH-IR sympathetic postganglionic, and NF200-IR myelinated mechanoreceptive nerve fibers, both within human and rat skin. Moreover, GR but not MR were localized in keratinocytes of the epidermal layer of human and rat skin. Overall, our results indicate considerable overlap in sensory neuron expression of MR and GR in humans and rats endorsing a common systems approach in mammals that may modulate the transmission of sensory information by MR and GR activation.
Learn More >There are no community-based studies investigating the association between sleep duration and postherpetic neuralgia (PHN) development. The aim of the current study was to examine the association of sleep with herpes zoster (HZ) incidence and PHN.
Learn More >Migraine is a disabling, chronic neurological disease leading to severe headache episodes affecting 13.2% of the Swedish population. Migraine leads to an extensive socio-economic burden in terms of healthcare costs, reduced workforce and quality of life (QoL) but studies of the health-economic consequences in a Swedish context are lacking. The objective of this study is to map the health-economic consequences of migraine in a defined patient population in terms of healthcare consumption, production loss and QoL in Sweden.
Learn More >We investigated resting-state (RS)-fMRI using independent component analysis (ICA) to determine the functional connectivity (FC) between networks in chronic migraine (CM) patients and their correlation with clinical features.
Learn More >Perturbation of neuronal excitability contributes to migraine. Neurosteroids modulate the activity of γ-aminobutyric acid A and N-methyl-d-aspartate receptors, and might be involved in the pathogenesis of migraine. Here, we measured plasma levels of four neurosteroids, i.e., allopregnanolone, epiallopregnanolone, dehydroepiandrosterone and deydroepiandrosterone sulfate, in patients affected by episodic migraine, chronic migraine, or cluster headache.
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