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P23.9 Somatosensory high-frequency oscillations in medication overuse headache
14th ECCN / 4th ICTMS/DCS P23.6 Study of the cortical changes induced by focal mechanical vibration on nociceptive pathways C. Pazzaglia1,2 , C. Vollono3 , F. Camerota4 , C. Celletti4 , L. Padua1,2 , C. Erra1 , M. Valeriani3 1 Department of Neuroscience, Institute of Neurology, Catholic University, Rome, Italy, 2 Don C. Gnocchi Onlus Foundation, Italy, 3 Division of Neurology, Ospedale Pediatrico Bambino Ges` u, IRCCS, Rome, Italy, 4 Physical Medicine and Rehabilitation Division, Umberto I Hospital, Rome, Italy Introduction: Focal mechanical vibration (FMV) is able to selectively stimulate the non-nociceptive Ab afferents. While FMV has proved useful in modulating motor function, its possible efficacy in pain relief is unknown. The laser evoked potential (LEP) recording is a method for the objective assessment of nociceptive pathways involved in the transmission of noxious stimuli. Previous studies showed that the electrical Ab afferent stimulation is able to reduce spontaneous pain, both experimentally induced and in painful diseases, and LEP amplitude. Objectives: The objectives of the current study are to evaluate if FMV may: (1) change the LEP amplitudes and/or latencies and (2) have an analgesic effect. Methods: Ten healthy volunteer have been studied. The subjects were evaluated in two different sessions in order to test both effective and sham FMV. LEPs were recorded from 4 scalp recording electrodes (Cz, Fz, T3, and T4) after stimulation of both the right and left radial and ulnar cutaneous territories. LEPs were recorded in a baseline condition and during either effective or sham FMV delivered over the right radial territory. Results: Neither the amplitudes nor the latencies of both the vertex N2/P2 and the contralateral N1 LEP components were changed by both effective and sham FMV, as compared to the baseline. The psychophysical evaluation of the laser-induced pain did not show any analgesic effect of the FMV. Conclusions: Our results show that FMV is ineffective in modifying the LEP components and in reducing physic laser pain. Further studies are needed to evaluate whether FMV might be useful in reducing a longer lasting pain. P23.7 Transcutaneous spinal direct current stimulation inhibits nociceptive spinal pathway conduction and increases pain tolerance in humans S. La Cesa1 , M. Vergari2 , A. Biasiotta1 , M. Gabriele1 , G. Di Stefano1 , C. Leone1 , C. Cambieri1 , G. Cruccu1 , M. Inghilleri1 , A. Priori2 1 Department of Neurological Sciences, University La Sapienza, Rome, a di Milano, Italy, 2 Dipartimento di Scienze Neurologiche, Universit` Milan, Italy Despite concerted efforts from pharmacologic research into neuropathic pain, many patients fail to achieve sufficient pain relief with medication alone. For this reason, increasing interest centres on neurostimulation techniques. We assessed whether transcutaneous spinal direct current stimulation (tsDCS) modulates conduction in ascending nociceptive spinal pathways. We measured changes induced by anodal and cathodal tsDCS over the thoracic spinal cord on face- and foot-laser evoked potentials (LEPs) and foot-cold pressor test responses in 20 healthy subjects. Whereas anodal tsDCS reduced the amplitude of the N1 and N2 components of foot-LEPs (P < 0.05) neither anodal nor cathodal tsDCS changed LEPs evoked by face stimulation. Pain tolerance to the cold pressor test was significantly higher after anodal than after cathodal tsDCS (P < 0.05). Conversely, no difference was found in the pain threshold or pain ratings to the cold pressor test between the two polarity conditions. Evidence that anodal tsDCS over the thoracic spinal cord impairs conduction in the ascending nociceptive spinal pathways, thus modulating LEPs and increasing pain tolerance in healthy subjects, calls for a clinical trial assessing the therapeutic effectiveness of tsDCS in patients with pain. P23.8 Painful neuropathy related to gastric bypass surgery for obesity C. Leone1 , A. Biasiotta1 , M. Nolano2 , C. Di Bonaventura1 , V. Provitera1 , A.M. Stancanelli2 , A. Truini1 , G. Cruccu1 1 Department of Neurological Sciences, University “La Sapienza”, Rome, Italy, 2 IRCCS Fondazione Maugeri, Telese Terme, Italy Peripheral neuropathy due to nutritional deficiency is a frequent and disabling complication of surgical procedures for obesity. We describe
S165 the case of a 19-years-old woman with an acute painful neuropathy after a surgical operation for morbid obesity. After four months a gastric bypass surgical operation the patient developed within one week ascending sensory deficits, ongoing pain, severe ataxia and leg muscle weakness. Cerebrospinal fluid analysis was normal. Nerve conduction study, laser evoked potentials and skin biopsy showed a distal symmetric axonopathy, affecting myelinated and unmyelinated afferent fibers and autonomic innervation of the skin. The patient had no specific nutritional deficit. Clinical and laboratory data improved after three months of multivitamin-mineral supplementation. This case report shows that the peripheral neuropathy due to surgical procedures for obesity may manifest as an acute distal axonopathy, damages both myelinated and unmyelinated fibers in parallel, and cause a subclinical damage of autonomic innervation of the skin. P23.9 Somatosensory high-frequency oscillations in medication overuse headache a2 , M. Gorini2 , M. Bracaglia2 , G. Coppola1 , C. Di Lorenzo2 , A. Curr` J. Schoenen3 , F. Pierelli2 1 Dept of Neurophysiology of Vision & Neurophthalmology, G.B. Bietti Eye Foundation, Rome, Italy, 2 Dept of Medical and Surgical Sciences and Biotechnologies, Latina, “Sapienza” University of Rome, Faculty of Pharmacy and Medicine, Latina, Italy, 3 Headache Research Unit. University Dept. of Neurology & GIGA-Neurosciences, Li` ege University, Li` ege, Belgium Objectives: In chronic pain syndromes less thalamic activation has previously been reported. Medication-overuse headache (MOH), a complication of episodic headaches, is characterized by more than 15 headache days per month and arises from an excessive intake of analgesics or specific anti-migraine drugs. A relative decreased metabolism in thalamic nuclei, belonging to the so called “pain network”, have been reported in medication overuse headache (MOH) patients. Somatosensory high-frequency oscillations (HFOs) have been suggested to reflect the activity of thalamo-cortical (early HFOs) and intracortical (late HFOs) neurons bursting at high frequencies. To explore thalamocortical activation and cortical inhibition we have compared early and late HFOs phase in MOH patients and healthy volunteers (HV). Methods: We have recorded median nerve somatosensory evoked potentials (SSEPs) from the contralateral parietal area in 20 MOH patients (ICHD-II 8.2) and in 22 HV. Digital filtering (450 750 Hz) was employed to extract 600 Hz oscillations superimposed on the conventional broad-band N20 of the SSEP. Results: We found a significant decrease of maximal amplitude (p = 0.03) and area under the rectified curve (p = 0.02) of the early SSEP HFO phase in patients compared to HV. By contrast, the 2 groups of subjects did not differ by the late SSEP HFO phase. Conclusions: These results suggest that somatosensory-induced thalamocortical activation is reduced in migraineurs who have developed MOH, while intracortical inhibition remains normal. The present results, in parallel with those coming from the study of the brain metabolism, confirm that medication overuse headache patients, like other chronic pain syndromes, presented abnormal brain activity, indicating a central origin for this condition. P23.10 Interaction between anxiety and cortical excitability in migraine children: a neurophysiological and psychological study C. Vollono1 , S. Tarantino1 , B. Sanci2 , C. De Ranieri2 , G. Biondi2 , A. Capuano1 , M. De Luca1 , F. Galli3 , F. Vigevano1 , V. Guidetti4 , M. Valeriani1 1 Neurology Division, Paediatric Hospital ‘Bambino Ges` u’ IRCCS, Rome, u’ IRCCS, Italy, 2 Pediatric Psychology, Paediatric Hospital ‘Bambino Ges` Rome, Italy, 3 Faculty of Psychology, La Sapienza University, Rome, Italy, 4 Child and Adolescent Neuropsychiatry, La Sapienza University, Rome, Italy Introduction: Migraine is a common neurological condition in children and adolescents causing a significant impact on quality of life. Previous studies in migraineurs showed a correlation between neurophysiological abnormality and emotional symptomatology. Objectives: Aim of this study was to characterize the correlation between neurophysiological and psychological data, concerning both internalizing and externalizing behavioural disorders.
S165 the case of a 19-years-old woman with an acute painful neuropathy after a surgical operation for morbid obesity. After four months a gastric bypass surgical operation the patient developed within one week ascending sensory deficits, ongoing pain, severe ataxia and leg muscle weakness. Cerebrospinal fluid analysis was normal. Nerve conduction study, laser evoked potentials and skin biopsy showed a distal symmetric axonopathy, affecting myelinated and unmyelinated afferent fibers and autonomic innervation of the skin. The patient had no specific nutritional deficit. Clinical and laboratory data improved after three months of multivitamin-mineral supplementation. This case report shows that the peripheral neuropathy due to surgical procedures for obesity may manifest as an acute distal axonopathy, damages both myelinated and unmyelinated fibers in parallel, and cause a subclinical damage of autonomic innervation of the skin. P23.9 Somatosensory high-frequency oscillations in medication overuse headache a2 , M. Gorini2 , M. Bracaglia2 , G. Coppola1 , C. Di Lorenzo2 , A. Curr` J. Schoenen3 , F. Pierelli2 1 Dept of Neurophysiology of Vision & Neurophthalmology, G.B. Bietti Eye Foundation, Rome, Italy, 2 Dept of Medical and Surgical Sciences and Biotechnologies, Latina, “Sapienza” University of Rome, Faculty of Pharmacy and Medicine, Latina, Italy, 3 Headache Research Unit. University Dept. of Neurology & GIGA-Neurosciences, Li` ege University, Li` ege, Belgium Objectives: In chronic pain syndromes less thalamic activation has previously been reported. Medication-overuse headache (MOH), a complication of episodic headaches, is characterized by more than 15 headache days per month and arises from an excessive intake of analgesics or specific anti-migraine drugs. A relative decreased metabolism in thalamic nuclei, belonging to the so called “pain network”, have been reported in medication overuse headache (MOH) patients. Somatosensory high-frequency oscillations (HFOs) have been suggested to reflect the activity of thalamo-cortical (early HFOs) and intracortical (late HFOs) neurons bursting at high frequencies. To explore thalamocortical activation and cortical inhibition we have compared early and late HFOs phase in MOH patients and healthy volunteers (HV). Methods: We have recorded median nerve somatosensory evoked potentials (SSEPs) from the contralateral parietal area in 20 MOH patients (ICHD-II 8.2) and in 22 HV. Digital filtering (450 750 Hz) was employed to extract 600 Hz oscillations superimposed on the conventional broad-band N20 of the SSEP. Results: We found a significant decrease of maximal amplitude (p = 0.03) and area under the rectified curve (p = 0.02) of the early SSEP HFO phase in patients compared to HV. By contrast, the 2 groups of subjects did not differ by the late SSEP HFO phase. Conclusions: These results suggest that somatosensory-induced thalamocortical activation is reduced in migraineurs who have developed MOH, while intracortical inhibition remains normal. The present results, in parallel with those coming from the study of the brain metabolism, confirm that medication overuse headache patients, like other chronic pain syndromes, presented abnormal brain activity, indicating a central origin for this condition. P23.10 Interaction between anxiety and cortical excitability in migraine children: a neurophysiological and psychological study C. Vollono1 , S. Tarantino1 , B. Sanci2 , C. De Ranieri2 , G. Biondi2 , A. Capuano1 , M. De Luca1 , F. Galli3 , F. Vigevano1 , V. Guidetti4 , M. Valeriani1 1 Neurology Division, Paediatric Hospital ‘Bambino Ges` u’ IRCCS, Rome, u’ IRCCS, Italy, 2 Pediatric Psychology, Paediatric Hospital ‘Bambino Ges` Rome, Italy, 3 Faculty of Psychology, La Sapienza University, Rome, Italy, 4 Child and Adolescent Neuropsychiatry, La Sapienza University, Rome, Italy Introduction: Migraine is a common neurological condition in children and adolescents causing a significant impact on quality of life. Previous studies in migraineurs showed a correlation between neurophysiological abnormality and emotional symptomatology. Objectives: Aim of this study was to characterize the correlation between neurophysiological and psychological data, concerning both internalizing and externalizing behavioural disorders.