Search results for "Measurement"
showing 10 items of 2918 documents
Differential effect of Incobotulinumtoxin A on pain, neurogenic flare and hyperalgesia in human surrogate models of neurogenic pain
2017
Background: The effectiveness of Botulinum-neurotoxin A (BoNT/A) to treat pain in human pain models is very divergent. This study was conducted to clarify if the pain models or the route of BoNT/A application might be responsible for these divergent findings. Methods: Sixteen healthy subjects (8 males, mean age 27 ± 5 years) were included in a first set of experiments consisting of three visits: (1) Visit: Quantitative sensory testing (QST) was performed before and after intradermal capsaicin injection (CAPS, 15 μg) on one thigh and electrical current stimulation (ES, 1 Hz) on the contralateral thigh. During stimulation pain and the neurogenic flare response (laser-Doppler imaging) were ass…
Illusion of Pain: Pre-existing Knowledge Determines Brain Activation of ‘Imagined Allodynia’
2007
Abstract Allodynia means that innocuous tactile stimulation is felt as pain. Accordingly, cerebral activations during allodynia or touch should markedly differ. The aim of this study was to investigate whether the imagination of allodynia affects brain processing of touch in healthy subjects. Seventeen healthy subjects divided into 2 subgroups were investigated: The first group (n = 7) was familiar with allodynia, based on previous pain studies, whereas the second group (n = 10) had never knowingly experienced allodynia. Using functional magnetic resonance imaging, 2 experimental conditions were investigated. In one condition the subjects were simply touched at their left hand, whereas duri…
Increased muscular and cutaneous pain sensitivity in cephalic region in patients with chronic tension-type headache
2005
Increased excitability of the central nervous system generated by repetitive and sustained pericranial myofascial nociception may be responsible for transformation of episodic tension-type headache into chronic form. We aimed to compare mechanical and electrical (intramuscular and cutaneous) pain thresholds in trapezius and anterior tibial regions between 20 patients with chronic tension type headache and 20 healthy controls. Pain thresholds to three types of electrical stimulation (single pulse, 2 and 100 Hz) were significantly lower in patients than in controls in trapezius muscle (P < 0.02) and in skin overlying the trapezius muscle (P < 0.05), whilst electrical pain thresholds did not d…
Quantitative sensory testing in the German Research Network on Neuropathic Pain (DFNS): Somatosensory abnormalities in 1236 patients with different n…
2009
Neuropathic pain is accompanied by both positive and negative sensory signs. To explore the spectrum of sensory abnormalities, 1236 patients with a clinical diagnosis of neuropathic pain were assessed by quantitative sensory testing (QST) following the protocol of DFNS (German Research Network on Neuropathic Pain), using both thermal and mechanical nociceptive as well as non-nociceptive stimuli. Data distributions showed a systematic shift to hyperalgesia for nociceptive, and to hypoesthesia for non-nociceptive parameters. Across all parameters, 92% of the patients presented at least one abnormality. Thermosensory or mechanical hypoesthesia (up to 41%) was more frequent than hypoalgesia (up…
Generalized hyperalgesia in patients with chronic tension-type headache.
2006
Increased pain sensitivity in the central nervous system may play an important role in the pathophysiology of chronic tension-type headache (CTTH). Previous studies using pain thresholds as a measure of central pain sensitivity have yielded inconsistent results and only a few studies have examined perception of muscle pain without involvement of adjacent tissues. It has been suggested that suprathreshold testing might be more sensitive than threshold measurements in evaluation of central hyperexcitability in CTTH. The aim of the study was to compare pain ratings to suprathreshold single and repetitive (2 Hz) electrical stimulation of muscle and skin in cephalic (temporal and trapezius) and…
Habituation and short-term repeatability of thermal testing in healthy human subjects and patients with chronic non-neuropathic pain
2008
We investigated habituation effects during thermal quantitative sensory testing (tQST) using 8 repetitive measurements for thermal detection and pain thresholds. The same measurements were repeated two days later. 39 healthy subjects and 36 patients with chronic non-neuropathic pain syndromes (migraine, tension-type headache, non-radicular back pain) were enrolled. The pain intensity was assessed using an 11-point (0-10) numerical rating scale. Measurements correlated significantly over the two days in both groups (r=0.41...0.62). Warm detection (WDT) and heat pain threshold (HPT) revealed no significant differences over these days. Cold detection (CDT) and pain thresholds (CPT) showed sign…
Perceptual correlates of nociceptive long-term potentiation and long-term depression in humans.
2004
Long-term potentiation (LTP) and long-term depression (LTD) of synaptic strength are ubiquitous mechanisms of synaptic plasticity, but their functional relevance in humans remains obscure. Here we report that a long-term increase in perceived pain to electrical test stimuli was induced by high-frequency electrical stimulation (HFS) (5 × 1 sec at 100 Hz) of peptidergic cutaneous afferents (27% above baseline, undiminished for >3 hr). In contrast, a long-term decrease in perceived pain (27% below baseline, undiminished for 1 hr) was induced by low-frequency stimulation (LFS) (17 min at 1 Hz). Pain testing with punctate mechanical probes (200 μm diameter) in skin adjacent to the HFS–LFS con…
Modality-specific sensory changes in humans after the induction of long-term potentiation (LTP) in cutaneous nociceptive pathways.
2007
The impact of long-term potentiation (LTP) in nociceptive pathways on somatosensory perception was examined by means of quantitative sensory testing (QST) in the ventral forearm of 12 healthy human subjects. Electrical high-frequency stimulation of the forearm skin (HFS; 5 x 1 s at 100 Hz and 10 x detection threshold) led to an abrupt increase of pain to single electrical test stimuli, which were applied through the same electrode (perceptual LTP +72%, p0.01). Perceptual LTP outlasted the 1-h observation period. The effects of HFS on somatosensory perception of natural test stimuli in the conditioned skin area were restricted to mechanical submodalities. Subjects exhibited a significant dec…
Effects of the NMDA-receptor antagonist ketamine on perceptual correlates of long-term potentiation within the nociceptive system
2007
We recently reported perceptual correlates of long-term potentiation (LTP) of synaptic strength within the nociceptive system demonstrating the functional relevance of LTP for human pain sensation. LTP is generally classified as NMDA-receptor dependent or independent. Here we show that low doses of the NMDA-receptor antagonist ketamine (0.25 mg/kg) prevented the long-term increase in perceived pain to electrical test stimuli, which was induced by high-frequency electrical stimulation (HFS) of nociceptive afferents. Whereas in a control experiment HFS led to a stable increase in perceived pain by 51% for the entire observation period of 1 h HFS given 4 min after i.v. ketamine was ineffective…
Zolmitriptan inhibits neurogenic inflammation and pain during electrical stimulation in human skin.
2014
Background Triptans are agonists to 5-HT 1B/D/F receptors, which are present on nociceptive neurons not only within but also beyond the trigeminal system. The aim of this study was to investigate whether zolmitriptan interacts with peptidergic nociceptive afferents in human skin. Methods Twenty participants (13 women, median age: 25; interquartile range: 23–26 years) entered the randomized, double-blind, cross-over study. Electrically induced neurogenic flare and pain was assessed after either placebo or zolmitriptan on the ventral thigh. Mechanical pain thresholds were investigated at baseline and after electrical stimulation at the stimulation site. Results The size of the neurogenic flar…