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See detailSustained effeciveness of occipital nerve stimulation in drug-resistant chronic cluster headache
MAGIS, Delphine ULg; Gerardy, Pierre-Yves; Remacle, Jean-Michel et al

in Headache (2011)

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See detailIntensity dependence of auditory evoked potentials during light interference in migraine.
Ambrosini, Anna; Coppola, Gianluca; Gerardy, Pierre-Yves et al

in Neuroscience letters (2011), 492(2), 80-3

Migraine patients show interictally a strong intensity dependence of auditory evoked cortical potentials (IDAP) and a lack of habituation of evoked potentials. Photic drive on high-frequency flash ... [more ▼]

Migraine patients show interictally a strong intensity dependence of auditory evoked cortical potentials (IDAP) and a lack of habituation of evoked potentials. Photic drive on high-frequency flash stimulation is another well-known interictal feature in migraineurs, associated with alpha-rhythm hyper-synchronisation. We compared therefore the influence of light stimulation on IDAP in healthy volunteers (HV) and migraine patients. A continuous flash stimulation was delivered during the recording of auditory evoked potentials at suprathreshold increasing stimulation intensities. IDAP was measured as the amplitude/stimulus intensity function (ASF) slope. In HV, the ASF slope decreased during flash stimulation, whereas, on average, there was no significant change in migraineurs. A closer analysis of migraineurs disclosed two subgroups of patients with no detectable clinical differences: one, the largest, in which the ASF slope was normal at baseline, but increased during light stimulation, the other with an increased ASF slope at rest and a decrease during light interference. Visual sensory overload is able to increase IDAP in the majority of migraineurs, which contrasts with HV. We hypothesise that this could be due to hyper-synchronisation of the alpha rhythm because of photic drive and possibly thalamo-cortical dysfunction. A minority of migraineurs have, like HV, an IDAP reduction during light interference. They are, however, characterised, unlike most HV, by a high IDAP at baseline. Besides underscoring the pathophysiological heterogeneity of migraine, these results suggest that light interference might improve the phenotyping of migraine patients who have a normal IDAP in the resting condition. [less ▲]

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See detailSustained efficacy of occipital nerve stimulation in drug-resistant chronic cluster headache after up to 5 years treatment
Magis, Delphine ULg; Gérardy, Pierre-Yves; Remacle, Jean-Michel et al

in Journal of Headache & Pain (2010), 11(Suppl 1), 15

Background. Drug-resistant chronic cluster headache (drCCH) is a devastating condition for which various invasive procedures have been tempted without any satisfactory effect. Our prospective pilot study ... [more ▼]

Background. Drug-resistant chronic cluster headache (drCCH) is a devastating condition for which various invasive procedures have been tempted without any satisfactory effect. Our prospective pilot study of great occipital nerve stimulation (ONS) in 8 drCCH patients showed encouraging results at 15 months (1). Methods. We recruited 15 patients with drCCH according to the previously published criteria of intractability (2). They were implanted with suboccipital stimulators on the side of their headache. Long-term follow-up was achieved by questionnaires administered during a headache consultation and/or by telephone interviews. Results. One patient had an immediate post operative infection of the material. Mean time with ONS was 28.8 months (range 3-60 months). Nine of the 14 remaining patients were totally pain-free (64%), 2 patients had an improvement in frequency exceeding 90% and one patient a 89% amelioration. Two patients did not respond or described mild improvement. Intensity of residual attacks was not improved by ONS. Four patients (29%) were able to reduce their prophylaxis. Common technical problems were battery depletion (N=8/14, 57%) and material infection (N=3/15, 20%). Recurrent battery replacement (until 2/ year in one patient) is now avoided by the availability of rechargeable batteries. Clinical peculiarities associated with ONS were occurrence of infrequent contralateral attacks (N=5/14, 36%), and/or isolated ispilateral autonomic attacks (N=5/14, 36%). Rapid attack recurrence after stimulator switch off was reported by 7/12 improved patients (58%). Two patients found ONS-related paresthesias unbearable; one had his stimulator removed, the other switched it off though he was objectively ameliorated. Subjectively, nine patients are very satisfied by ONS and one patient moderately satisfied. Conclusions. Our long-term follow-up confirms the efficacy of ONS in drCCH, which remains a safe and well-tolerated technique. The occurrence of contralateral attacks and isolated autonomic attacks in nearly 50% of ONS responders may have therapeutic and pathophysiological implications. [less ▲]

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See detailCentral neuromodulation in cluster headache patients treated with occipital nerve stimulators: A PET study
Magis, Delphine ULg; Bruno, Marie-Aurélie ULg; Fumal, Arnaud ULg et al

in Acta Neurologica Belgica (2010), 110(Suppl 1), 17

OBJECTIVES: Use functional brain imaging to explore activity changes in centres involved in trigeminal pain processing and control before and after occipital neurostimulation in drug-resistant chronic ... [more ▼]

OBJECTIVES: Use functional brain imaging to explore activity changes in centres involved in trigeminal pain processing and control before and after occipital neurostimulation in drug-resistant chronic cluster headache patients. BACKGROUND: Occipital nerve stimulation (ONS) provides relief to about 60% of patients suffering from drug-resistant chronic cluster headache (drCCH). Its mode of action, however, remains elusive, but the long latency to meaningful effect suggests that ONS induces slow neuromodulation. METHODS: Ten drCCH patients underwent an 18FDG-PET scan after ONS durations varying between 0 and 30 months. All were scanned with ongoing ONS (ON) and with the stimulator switched OFF. RESULTS: After 6-30 months of ONS, 3 patients were pain free and 4 had a ≥ 90% reduction of attack frequency (responders). In patients overall compared to controls, several areas of the pain matrix were hypermetabolic: ipsilateral hypothalamus, midbrain and ipsilateral lower pons. All normalized after ONS, except the hypothalamus. Switching ON or OFF the stimulator had little influence on brain glucose metabolism. The perigenual anterior cingulate cortex (PACC) was hyperactive in ONS responders compared to non-responders. INTERPRETATION AND CONCLUSIONS: Metabolic normalization in the pain neuromatrix and lack of short-term changes induced by the stimulation support the hypothesis that ONS acts in drCCH through slow neuromodulatory processes. Selective activation in responders of PACC, a pivotal structure in the endogenous opioid system, suggests that ONS may restore balance within dysfunctioning pain control centres. That ONS is nothing but a symptomatic treatment might be illustrated by the persistent hypothalamic hypermetabolism which could explain why autonomic attacks may persist despite pain relief and why cluster attacks recur shortly after stimulator arrest. [less ▲]

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