Publications by authors named "Kleggetveit I"

Article Synopsis
  • - The study evaluated the effectiveness of the 5.07/10 g monofilament test for diagnosing diabetic polyneuropathy (DPN) in patients referred for neurological assessments, considering factors like age, sex, and neuropathic pain (NP).
  • - Out of 506 patients, the test showed moderate sensitivity (0.60) and high specificity (0.82), but performed poorly in females, those with NP, and patients aged 50 and older, with disease severity not impacting its accuracy.
  • - The findings suggest that the monofilament test is not a reliable diagnostic tool for DPN, particularly for certain demographics, and the study advises against its use in clinical settings.
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Neuropathy can have many causes, some less well known than others. In this article, we present the case of a young man with progressive neurological deficit over several months. The cause was found to be an increasing social problem.

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Pain is a common symptom in patients referred to polyneuropathy assessment. Diagnostic evaluation and choice of treatment may depend on whether the pain is likely to be neuropathic or not. This study aimed to investigate the diagnostic accuracy of 3 tools commonly used to differentiate between neuropathic and nonneuropathic pain.

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Diabetic peripheral neuropathy (DPN) affects a large proportion of people with diabetes, and early detection is essential to prevent further progression. Widespread clinical testing relies on simplicity and cost-effectiveness of examination. Early signs of DPN may be detected by assessing the sudomotor nerves, and sudomotor activity can be measured by bioimpedance.

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Article Synopsis
  • The study aimed to categorize patients with complex regional pain syndrome (CRPS) based on quantitative sensory testing (QST) results to understand different pain characteristics, including ongoing and paroxysmal pain.
  • Out of 61 CRPS patients, 43 were classified with CRPS type 1 and 18 with type 2, resulting in three subgroups based on thermal sensitivity, with those experiencing thermal allodynia showing a higher prevalence of paroxysmal pain.
  • The findings indicate that cold allodynia might arise from hyper-excitability of skin nociceptors, suggesting a complex relationship between various pain sensations and underlying mechanisms, rather than solely small fiber degeneration.
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  • High-threshold mechanosensitive nociceptors and "silent" nociceptors in human skin both have similar electrical thresholds when stimulated at 4 Hz, but they serve different functions, especially in chronic pain scenarios.
  • Transcutaneous electrical stimulation with half-sine wave pulses was tested in healthy volunteers, showing that pain perception and thresholds were dependent on stimulation intensity.
  • Results indicated that mechanosensitive nociceptors were activated more readily than silent nociceptors, leading to the conclusion that specific stimulation protocols can effectively target different types of nociceptors for pain management.
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  • HNPP is an inherited neuropathy linked to a deficiency of the PMP-22 protein, resulting from deletions or mutations on chromosome 17, leading to recurrent nerve issues, particularly in areas prone to pressure.
  • The study aimed to examine the presence of pain in HNPP patients and assess small nerve fiber function through quantitative sensory testing (QST) and sudomotor function tests.
  • Among the 19 patients evaluated, many reported numbness and signs of general neuropathy, while a subset experienced various types of pain, particularly in the feet, highlighting potential dysfunction in small nerve fibers.
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The chronic pain syndrome inherited erythromelalgia (IEM) is attributed to mutations in the voltage-gated sodium channel (NaV) 1.7. Still, recent studies targeting NaV1.

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Article Synopsis
  • Small fiber neuropathy (SFN) is a persistent pain condition with limited treatment options; a case study highlights an individualized treatment response using iPSC technology in a therapy-resistant patient.
  • In the study, the patient's specific nociceptor excitability was measured in vitro, revealing changes that were corrected by lacosamide, an FDA-approved medication, leading to significant pain reduction from 7.5 to 1.5 on a visual analogue scale.
  • Results showed objective evidence of decreased peripheral nociceptor activity through microneurography, demonstrating successful application of precision medicine to tailor treatment based on the patient's unique cellular responses.
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Background and aim "Gain-of-function" mutations in voltage-gated sodium channel NaV1.7 have been linked to erythromelalgia (EM), characterized by painful hot and red hands and feet. We investigated the proportion of patients with EM that carry a mutation in NaV1.

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  • Fabry patients often first experience neuropathic pain, which is linked to changes in small nerve fibers, eventually leading to reduced sensory perception.* -
  • A study comparing Fabry patients to a Gla mouse model showed similar patterns of skin innervation and sensory abnormalities in both, indicating a shared underlying issue.* -
  • Electrophysiological tests revealed that Gla nociceptors had decreased voltage-gated Na and Ca currents, altering their function and contributing to sensory perception loss.*
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Objectives: Nociceptive thresholds and supra-threshold pain ratings as well as their reduction upon local injection with lidocaine were compared between healthy subjects and patients with erythromelalgia (EM).

Methods: Lidocaine (0.25, 0.

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Introduction: The sodium channel Nav 1.9 is expressed in peripheral nociceptors and has recently been linked to human pain conditions, but the exact role of Nav 1.9 for human nociceptor excitability is still unclear.

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Gain-of-function mutations in the tetrodotoxin (TTX) sensitive voltage-gated sodium channel (Nav) Nav1.7 have been identified as a key mechanism underlying chronic pain in inherited erythromelalgia. Mutations in TTX resistant channels, such as Nav1.

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Objectives: Nerve growth factor (NGF) is a protein important for growth and survival, but also for modulation of sensitivity of nociceptors and sympathetic neurons. The purpose of the present study was to investigate the effects of reduced NGF signaling in patients with hereditary sensory and autonomic neuropathies type V, congenital insensitivity to pain, caused by a mutation of the NGFβ gene, including a characterization of single nociceptive fibers using microneurography (MNG).

Materials And Methods: One homozygote and 2 heterozygote patients with this mutation were examined with electromyography/neurography, thermal testing, quantitative sudomotor axon reflex test, and electrically induced axon reflex erythema in addition to MNG.

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Article Synopsis
  • Complex regional pain syndrome (CRPS) is a debilitating chronic pain condition affecting limbs, with two types: CRPS 1 (without nerve lesion) and CRPS 2 (with nerve lesion), often following injuries, surgeries, or sometimes without a clear cause.
  • A study of 55 patients diagnosed with CRPS aimed to assess the time taken for diagnosis and the impact of subsequent orthopedic surgeries on pain levels, revealing a mean diagnosis time of 3.9 years, with many patients experiencing worsened symptoms post-surgery.
  • Out of the patients studied, 38 had CRPS type 1 and 17 had type 2, with various types of injuries leading to the condition; 27 underwent
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Background: Complex regional pain syndrome (CRPS) may occur following fractures, surgery or different trauma. Development of CRPS following snake-bite has only been published in three reports (from Turkey, Nepal and Korea), although snake bites occur frequently world-wide. There has been no report from Western Europe.

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Seven patients diagnosed with erythromelalgia (EM) were investigated by microneurography to record from unmyelinated nerve fibers in the peroneal nerve. Two patients had characterized variants of sodium channel Nav1.7 (I848T, I228M), whereas no mutations of coding regions of Navs were found in 5 patients with EM.

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Background: Inflammatory mediators activate and sensitize nociceptors. Tissue acidosis with low pH of 5.5 often accompanies inflammation and could enhance inflammatory pain and sensitization.

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Background: Microneurography is a neurophysiological technique which enables recording from single peripheral nerve fibres in persons who are awake. The method is only used in research. We discuss how microneurography has been used to map nerve-fibre functions under normal circumstances and in chronic pain conditions.

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