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Laser evoked potentials Habituation

Marina de Tommaso, Katia Ricci, Giuseppe Libro, Eleonora Vecchio, Marianna Delussi, Anna Montemurno, Giuseppe Lopalco, Florenzo Iannone
Background: A dysfunction of pain processing at central and peripheral levels was reported in fibromyalgia (FM). We aimed to correlate laser evoked potentials (LEPs), Sympathetic Skin Response (SSR), and clinical features in FM patients. Methods: Fifty FM patients and 30 age-matched controls underwent LEPs and SSR by the right hand and foot. The clinical evaluation included FM disability (FIQ) and severity scores (WPI), anxiety (SAS) and depression (SDS) scales, and questionnaires for neuropathic pain (DN4)...
2017: Pain Research and Treatment
Martin Uglem, Petter Moe Omland, Marit Stjern, Gøril Bruvik Gravdahl, Trond Sand
BACKGROUND: Migraineurs seem to have cyclic variations in cortical excitability in several neurophysiological modalities. Laser-evoked potentials (LEP) are of particular interest in migraine because LEP specifically targets pain pathways, and studies have reported different LEP-changes both between and during headaches. Our primary aim was to explore potential cyclic variations in LEP amplitude and habituation in more detail with a blinded longitudinal study design. METHODS: We compared N1 and N2P2 amplitudes and habituation between two blocks of laser stimulations to the dorsal hand, obtained from 49 migraineurs with four sessions each...
October 2, 2017: Journal of Headache and Pain
Eleonora Vecchio, Eleonora Gentile, Giovanni Franco, Katia Ricci, Marina de Tommaso
Background Transcutaneous external supraorbital nerve stimulation has emerged as a treatment option for primary headache disorders, though its action mechanism is still unclear. Study aim In this randomized, sham-controlled pilot study we aimed to test the effects of a single external transcutaneous nerve stimulation session on pain perception and cortical responses induced by painful laser stimuli delivered to the right forehead and the right hand in a cohort of migraine without aura patients and healthy controls...
January 1, 2017: Cephalalgia: An International Journal of Headache
M de Tommaso, K Ricci, A Montemurno, E Vecchio
OBJECTIVE: This study aimed to evaluate age-related changes in laser-evoked potential (LEP) features, including habituation, via trigeminal and hand stimulation in a large group of healthy volunteers. METHODS: We recorded the LEPs by right-hand stimulation in 237 healthy subjects and by stimulation of the right supraorbital zone in 170 cases. The subjects ranged in age from 7 to 72 years and were divided into six groups by age. RESULTS: At the trigeminal level, the N2 and P2 latencies were significantly shorter and the N2-P2 amplitude was significantly larger in the 7-17 age group than in the other groups...
July 2017: European Journal of Pain: EJP
P Hüllemann, C von der Brelie, G Manthey, J Düsterhöft, A K Helmers, M Synowitz, R Baron
BACKGROUND: Repetitive painful laser stimuli lead to physiological laser-evoked potential (LEP) habituation, measurable by a decrement of the N2/P2 amplitude. The time course of LEP-habituation is reduced in the capsaicin model for peripheral and central sensitization and in patients with migraine and fibromyalgia. In the present investigation, we aimed to assess the time course of LEP-habituation in a neuropathic pain syndrome, i.e. painful radiculopathy. METHODS: At the side of radiating pain, four blocks of 25 painful laser stimuli each were applied to the ventral thigh at the L3 dermatome in 27 patients with painful radiculopathy...
May 2017: European Journal of Pain: EJP
Matthew D Jones, Janet L Taylor, John Booth, Benjamin K Barry
Exercise-induced hypoalgesia is well described, but the underlying mechanisms are unclear. The aim of this study was to examine the effect of exercise on somatosensory evoked potentials, laser evoked potentials, pressure pain thresholds and heat pain thresholds. These were recorded before and after 3-min of isometric elbow flexion exercise at 40% of the participant's maximal voluntary force, or an equivalent period of rest. Exercise-induced hypoalgesia was confirmed in two experiments (Experiment 1-SEPs; Experiment 2-LEPs) by increased pressure pain thresholds at biceps brachii (24...
2016: Frontiers in Physiology
Costanza Pazzaglia, Elisa Testani, Rocco Giordano, Luca Padua, Massimiliano Valeriani
Increased pain perception due to the expectation to feel more pain is called nocebo effect. The present study aimed at investigating whether: (1) the mere expectation to feel more pain after the administration of an inert drug can affect the laser-pain rating and the laser-evoked potential (LEP) amplitude, and (2) the learning potentiates the nocebo effect. Eighteen healthy volunteers were told that an inert cream, applied on the right hand, would increase the laser pain and LEP amplitude to right hand stimulation...
October 1, 2016: Neuroscience
Marina de Tommaso, Marianna Delussi, Katia Ricci, Anna Montemurno, Irene Carbone, Eleonora Vecchio
Onabotulintoxin A (BontA) is an efficacious preventive treatment for chronic migraine, though the specific mechanism of action is still under discussion. The study aims: (1) To evaluate pain processing modifications in chronic migraine patients (CM) under single BontA administration in pericranial muscles, by means of CO² Laser Evoked Potentials (LEPs) obtained by the stimulation of the skin over the right frontal and trapezius injection sites and hand dorsum, in a double blind placebo controlled crossover design...
May 25, 2016: Toxins
Eleonora Vecchio, Katia Ricci, Anna Montemurno, Marianna Delussi, Sara Invitto, Marina de Tommaso
Migraine is characterized by an altered cortical excitability. Because transcranial direct current stimulation (tDCS) can change brain activity noninvasively, it is possible to hypothesize its efficacy in modulating pain in migraine. In this study, we compared the effects of tDCS of the left primary motor cortex (M1) and left dorsolateral prefrontal cortex (DLPFC) both on subjective pain and on evoked responses induced by laser stimulation (LEPs). Thirty-two patients and sixteen controls were randomized to receive sham stimulation and real tDCS with the anode centered over M1 or DLPFC...
July 28, 2016: Neuroscience Letters
Costanza Pazzaglia, Filippo Camerota, Claudia Celletti, Ileana Minciotti, Elisa Testani, Luca Padua, Massimiliano Valeriani
BACKGROUND: Nonpainful tactile and electrical stimulation of the large myelinated fibers reduces spontaneous pain and the amplitude of laser-evoked potentials (LEPs), which represent the most reliable technique to assess the nociceptive pathway function. Focal mechanical vibration stimulates the Aβ afferents selectively; thus, it is conceivable its action on nociceptive pathways. AIM: The aim of this study was to investigate the effect of vibratory stimuli, activating either both muscle and skin receptors or cutaneous afferents only on the LEPs and subjective laser-pain rating...
January 2017: Pain Practice: the Official Journal of World Institute of Pain
P Hüllemann, R Watfeh, Y-Q Shao, A Nerdal, A Binder, R Baron
OBJECTIVE: Laser-evoked potential (LEP) habituation was investigated under the influence of capsaicin-induced peripheral and central sensitization. MATERIAL AND METHODS: Fifteen subjects received 100 repetitive painful laser stimuli at the right hand dorsum at primary (application area; condition I) and secondary areas (beyond application area; condition II) in two different sessions after applying capsaicin topically. Conditions I and II were compared to a control condition without capsaicin application...
December 2015: Neurophysiologie Clinique, Clinical Neurophysiology
Marina de Tommaso, Vittorio Sciruicchio, Katia Ricci, Anna Montemurno, Francesco Gentile, Eleonora Vecchio, Maria Grazia Foschino Barbaro, Michele Simeoni, Marvita Goffredo, Paolo Livrea
OBJECTIVES: Few studies have addressed central sensitization symptoms and pain processing in childhood migraine. Our aims were to examine pain sensitivity and responses, including habituation, evoked by CO2 laser stimuli (laser-evoked potentials (LEPs)) in a cohort of children with migraine compared to non-migraine controls and to determine the correlation between LEP features and signs of central sensitization. METHODS: Thirty-five patients 8-15 years of age with migraines without aura were evaluated during the inter-critical phase and were compared to 17 controls...
April 2016: Cephalalgia: An International Journal of Headache
P Hüllemann, Y Q Shao, G Manthey, A Binder, R Baron
BACKGROUND: Recent studies applied laser-evoked potentials (LEP) for the analysis of small nerve fibre function and focused on the detection of stable C-fibre-mediated potentials (C-LEPs); high technical requirements were needed. The diagnostic significance is still controversially discussed. So far, only few studies focused on the susceptibility of C-LEPs to distraction and other influences. We hypothesized that C-LEPs are altered by habituation processes and distraction. METHODS: Twelve subjects were tested with a C-fibre laser set-up (neodymium:yttrium-aluminium-perovskite laser with a 10-mm beam diameter and 10-ms stimulus time) at the left perioral area...
March 2016: European Journal of Pain: EJP
S Schuh-Hofer, U Baumgärtner, R-D Treede
BACKGROUND: Sleep deprivation induces hyperalgesia. However, this pro-nociceptive effect is not reflected at the electrophysiological level, since sleep restricted subjects show amplitude reduction of Laser-evoked Potentials (LEP). We aimed to explore the contribution of habituation to this paradoxical LEP amplitude decline. METHODS: We compared LEP's of 12 healthy students (23.2 ± 1.1 years) after habitual sleep (HS) and a night of total sleep deprivation (TSD)...
September 2015: European Journal of Pain: EJP
Siv Steinsmo Ødegård, Petter Moe Omland, Kristian Bernhard Nilsen, Marit Stjern, Gøril Bruvik Gravdahl, Trond Sand
OBJECTIVE: Sleep restriction seems to change our experience of pain and reduce laser evoked potential (LEP) amplitudes. However, although LEP-habituation abnormalities have been described in painful conditions with comorbid sleep impairment, no study has previously measured the effect of sleep restriction on LEP-habituation, pain thresholds, and suprathreshold pain. METHOD: Sixteen males and seventeen females (aged 18-31years) were randomly assigned to either two nights of delayed bedtime and four hours sleep (partial sleep deprivation) or nine hours sleep...
October 2015: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Marina de Tommaso, Maria Nolano, Florenzo Iannone, Eleonora Vecchio, Katia Ricci, Marta Lorenzo, Marianna Delussi, Francesco Girolamo, Vito Lavolpe, Vincenzo Provitera, Annamaria Stancanelli, Giovanni Lapadula, Paolo Livrea
In fibromyalgia (FM), reduced habituation of laser-evoked potentials (LEPs) suggests a dysfunction of pain processing at a central level. In this study, we aimed to further examine the nociceptive pathways at the peripheral to the central level in a large group of FM patients by means of LEPs and skin biopsy, in light of healthy controls findings and main clinical features. One hundred and ninety-nine FM patients and 109 age- and sex-matched controls were submitted to LEPs by the dorsum of the right hand and the skin over the right chest and knee tender point stimulation...
March 2014: Journal of Neurology
Diana M E Torta, Valéry Legrain, Maxime Algoet, Etienne Olivier, Julie Duque, André Mouraux
Continuous theta burst stimulation (cTBS) applied over the primary motor cortex (M1) can alleviate pain although the neural basis of this effect remains largely unknown. Besides, the primary somatosensory cortex (S1) is thought to play a pivotal role in the sensori-discriminative aspects of pain perception but the analgesic effect of cTBS applied over S1 remains controversial. To investigate cTBS-induced analgesia we characterized, in two separate experiments, the effect of cTBS applied either over M1 or S1 on the event-related brain potentials (ERPs) and perception elicited by nociceptive (CO2 laser stimulation) and non-nociceptive (transcutaneous electrical stimulation) somatosensory stimuli...
2013: PloS One
P Hüllemann, F Mahn, Y-Q Shao, R Watfeh, G Wasner, A Binder, R Baron
BACKGROUND: In the scientific approach to central processing of pain, the habituation phenomenon has been frequently described. Recent studies mentioned electrophysiological habituation during the recording of laser-evoked potentials (LEP). In this study we intended to test whether habituation can be reproducibly induced by repetitive painful laser stimuli and simultaneously measured with LEP. Inspired by findings from previous imaging studies that showed bilateral activation of the operculo-insular cortices, we hypothesized that repetitive painful laser stimuli applied to one hand lead to bihemispheral LEP amplitude habituation...
November 2013: European Journal of Pain: EJP
Laura Di Clemente, Francesca Puledda, Antonella Biasiotta, Alessandro Viganò, Edoardo Vicenzini, Andrea Truini, Giorgio Cruccu, Vittorio Di Piero
BACKGROUND: Lack of habituation during repetitive stimulation is the most consistent interictal abnormality of cortical information processing observed in migraine. Preventive migraine treatments might act by stabilizing cortical excitability level and thus the habituation to external stimuli. METHODS: We examined the effects of preventive treatment with topiramate on migraineur's habituation to nociceptive stimulation. Scalp potentials were evoked by Nd-YAP Laser stimulation of the hand dorsum and supraorbital region in 13 patients with migraine without aura (MO) and 15 healthy volunteers (HV)...
2013: Journal of Headache and Pain
U Baumgärtner, W Greffrath, R-D Treede
Laser-evoked potentials are the most extensively validated method to objectively assess nociceptive pathway function in humans. Here, we review merits and shortcomings of alternative techniques using different principles of stimulus generation to stimulate Aδ- or C-fibers. Fast ramp contact heat stimuli yield reproducible responses; however, stimulus location needs to be changed to reduce peripheral habituation, and the limited steepness of temperature ramps may result in response jitter and absence of averaged responses even in some healthy subjects...
October 2012: Neurophysiologie Clinique, Clinical Neurophysiology
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