Francomichele Puca

Reduced habituation to experimental pain in migraine patients: a CO2 laser evoked potential study

The habituation to sensory stimuli of different modalities is reduced in migraine patients. However, the habituation to pain has never been evaluated. Our aim was to assess the nociceptive pathway function and the habituation to experimental pain in patients with migraine. Scalp potentials were evoked by CO2 laser stimulation (laser evoked potentials, LEPs) of the hand and facial skin in 24 patients with migraine without aura (MO), 19 patients with chronic tension‐type headache (CTTH), and 28 control subjects (CS). The habituation was studied by measuring the changes of LEP amplitudes across three consecutive repetitions of 30 trials each (the repetitions lasted 5 min and were separated by 5‐min intervals). The slope of the regression line between LEP amplitude and number of repetitions was taken as an index of habituation. The LEPs consisted of middle‐latency, low‐amplitude responses (N1, contralateral temporal region, and P1, frontal region) followed by a late, high‐amplitude, negative–positive complex (N2/P2, vertex). The latency and amplitude of these responses were similar in both patients and controls. While CS and CTTH patients showed a significant habituation of the N2/P2 response, in MO patients this LEP component did not develop any habituation at all after face stimulation and showed a significantly lower habituation than in CS after hand stimulation. The habituation index of the vertex N2/P2 complex exceeded the normal limits in 13 out of the 24 MO patients and in none of the 19 CTTH patients (P<0.0001; Fishers exact test). Moreover, while the N1–P1 amplitude showed a significant habituation in CS after hand stimulation, it did not change across repetitions in MO patients. In conclusion, no functional impairment of the nociceptive pathways, including the trigeminal pathways, was found in either MO or CTTH patients. But patients with migraine had a reduced habituation, which probably reflects an abnormal excitability of the cortical areas involved in pain processing.

The Migraine Disability Assessment (MIDAS) Questionnaire: Translation and Reliability of the Italian Version

We have developed and tested an Italian version of the Migraine Disability Assessment (MIDAS) questionnaire, an established instrument for assessing headache-related disability. A multistep process was used to translate and adapt the questionnaire into Italian, which was then tested on 109 Italian migraine without aura patients, 86 (78.9%) of whom completed the form a second time 21 days later. Overall MIDAS score had good test–retest reliability (Spearmans correlation 0.77), closely similar to that found in English-speaking migraineurs, and individual responses were also satisfactorily reliable. Internal consistency was good (Cronbachs alpha 0.7). These findings support the use of the MIDAS questionnaire as a clinical and research tool with Italian patients.

Applicability of the 1988 IHS Criteria to Headache Patients Under the Age of 18 Years Attending 21 Italian Headache Clinics

Seven hundred nineteen young patients attending 21 Italian headache care settings were evaluated by a diagnostic headache interview and a neurological examination. Headache disorders were classified according to the current 1988 criteria of the International Headache Society (IHS); 54.9% of the patients suffered from migraine, 33.9% from tension‐type headache, 1.9% from secondary headache, and 3.4% had non‐classifiable headache. A further 5.9% of the patients were not classified due to incomplete questionnaires.

Placebo-controlled comparison of effervescent acetylsalicylic acid, sumatriptan and ibuprofen in the treatment of migraine attacks.

Acetylsalicylic acid (ASA) in combination with metoclopramide has been frequently used in clinical trials in the acute treatment of migraine attacks. Recently the efficacy of a new high buffered formulation of 1000 mg effervescent ASA without metoclopramide compared to placebo has been shown. To further confirm the efficacy of this new formulation in comparison with a triptan and a nonsteroidal anti-inflammatory drug (ibuprofen) a three-fold crossover, double-blind, randomized trial with 312 patients was conducted in Germany, Italy and Spain. Effervescent ASA (1000 mg) was compared to encapsulated sumatriptan (50 mg), ibuprofen (400 mg) and placebo. The percentage of patients with reduction in headache severity from moderate or severe to mild or no pain (primary endpoint) was 52.5% for ASA, 60.2% for ibuprofen, 55.8% for sumatriptan and 30.6% for placebo. All active treatments were superior to placebo (P < 0.0001), whereas active treatments were not statistically different. The number of patients who were pain-free at 2 h was 27.1%, 33.2%, 37.1% and 12.6% for those treated with ASA, ibuprofen, sumatriptan or placebo, respectively. The difference between ASA and sumatriptan was statistically significant (P = 0.025). With respect to other secondary efficacy criteria and accompanying symptoms no statistically significant differences between ASA and ibuprofen or sumatriptan were found. Drug-related adverse events were reported in 4.1%, 5.7%, 6.6% and 4.5% of patients treated with ASA, ibuprofen sumatriptan or placebo. This study showed that 1000 mg effervescent ASA is as effective as 50 mg sumatriptan and 400 mg ibuprofen in the treatment of migraine attacks regarding headache relief from moderate/severe to mild/no pain at 2 h. Regarding pain-free at 2 h sumatriptan was most effective.

Abnormal brain processing of cutaneous pain in patients with chronic migraine.

&NA; Syndromes with chronic daily headache include chronic migraine (CM). The reason for the transformation of migraine into chronic daily headache is still unknown. In this study, we aimed to evaluate heat pain thresholds and event‐related potentials following CO2‐laser thermal stimulation (LEPS) in hand and facial regions in patients with CM, to show changes in nociceptive brain responses related to dysfunction of pain elaboration at the cortical level. The results were compared with findings from normal control subjects and from subjects who suffer from migraine without aura. The effects of stimulus intensity, subjective pain perception and attention were monitored and compared with features of the LEPS. Twenty‐five CM patients, 15 subjects suffering from migraine without aura and 15 normal control subjects were enrolled in the study. LEPS amplitude variation was reduced in CM patients with respect to the perceived stimulus intensity, in comparison with migraine without aura patients and control subjects. In both headache groups, the distraction from the painful laser stimulus induced by an arithmetic task failed to suppress the LEPS amplitude, in comparison with control subjects. These results suggest an abnormal cortical processing of nociceptive input in CM patients, which could lead to the chronic state of pain. In both headache groups, an inability to reduce pain elaboration during an alternative cognitive task emerged as an abnormal behaviour probably predisposing to migraine.

Abnormal brain processing of cutaneous pain in migraine patients during the attack.

We examined cutaneous pain thresholds using CO(2) laser stimuli during migraine attacks, and defined the evoked cortical potential characteristics. Ten patients without aura were studied during attacks and for at least 72 h subsequently. Pain stimuli were generated on the dorsum of both hands and the right and left supraorbital zones, using pulses from a CO(2) laser. Absolute latencies of scalp potentials were measured at the highest peak of each response component, and the peak-to-peak amplitudes of N2a-P2 components were recorded. Cutaneous pain thresholds were significantly reduced on both the symptomatic and non-symptomatic sides during the attack, in comparison with the headache-free phase. The N2a-P2 complexes also increased in amplitude during attacks in comparison with the pain-free side. Thus, cutaneous hyperalgesia occurs during migraine attack, and is subtended by central sensitization phenomena, probably involving the cortex.

EEG features in juvenile migraine: topographic analysis of spontaneous and visual evoked brain electrical activity: a comparison with adult migraine.

Topographic analysis of spontaneous and steady-state visual evoked brain electrical activity was carried out between attacks in 82 migraine patients (40 youths and 42 adults). In adult migraine with aura a significant increase of delta rhythm percentage power was observed compared with migraine without aura and age-matched controls. Children suffering from migraine both with aura and without aura had an increased theta rhythm compared to normal controls. The presence of alpha interhemispheric asymmetry discriminated between migraine with aura and without aura, just as in adults. An increased amplitude of the SVEP F1 component with a tendency to the spread of visual reactivity was observed in juvenile migraine with and without aura; this pattern was not dissimilar from the one previously observed in adult migraine with and without aura. Abnormal photic driving in migraine is independent of age and type of migraine.

EEG spectral analysis in migraine without aura attacks.

In 16 patients suffering from migraine without aura, we examined quantitative EEG and steady-state visual evoked potentials (SSVEPs) at 27 Hz stimulation during the critical phase of migraine and in attack-free periods. The main spontaneous EEG abnormalities found during the critical phase were the slowing and asymmetry of the dominant frequency in the alpha range. The amplitude of the SSVEP F1 component was significantly reduced during the attack phase compared with the intercritical phase; in the latter condition the visual reactivity to 27 Hz stimulus was increased over almost the entire scalp compared with normal subjects. The EEG abnormalities confirm a fluctuating modification of alpha activity during the migraine attack, probably related to a functional disorder. The suppression of visual reactivity during the migraine attack could be related to a phenomenon of neuronal depolarization such as spreading depression, occurring in a situation of central neuronal increased excitability predisposing to migraine attacks.

Modulation of trigeminal reflex excitability in migraine: effects of attention and habituation on the blink reflex

Abstract The modulation of trigeminal reflex excitability in migraine patients was evaluated during the asymptomatic phase by studying the effects of attention, habituation and preconditioning stimulus on the R2 and R3 components of the blink reflex (BR). Fifty patients suffering from migraine without aura, 20 affected by migraine with aura and 35 sex- and age-matched controls were selected. In subgroups of migraine with-aura and without-aura patients, and normal controls, the blink reflex was elicited during different cognitive situations: (a) spontaneous mental activity; (b) stimulus anticipation; (c) recognition of target numbers. In the remaining subjects, R2 and R3 habituation was evaluated by repetitive stimulation at 1, 5, 10, 15, 20, 25 and 30 s intervals. The R2 and R3 recovery curves were also computed. A reduced R3 threshold with a normal pain threshold was found in migraine with-aura and without-aura patients; the R3 component was not significantly correlated with the pain thresholds in patients and controls. The R2 and R3 components were less influenced by the warning of the stimulus in migraine without-aura and migraine with-aura patients, in comparison with the control group. A slight increase of both R2 and R3 recovery after preconditioning stimulus was also observed in migraine patients, probably caused by a phenomenon of trigeminal hyperexcitability persisting after the last attack. The abnormal BR modulation by alerting expresses in migraine a dysfunction of adaptation capacity to environmental conditions, probably predisposing to migraine.

Zolmitriptan reverses blink reflex changes induced during the migraine attack in humans.

The question about the 5-hydroxytryptamine (5-HT)(1B-1D) receptors agonists, if the clinical efficacy in migraine attacks is linked with the action at the central level or at the peripheral one, is still unresolved. We evaluated the effects of zolmitriptan and sumatriptan on blink reflex in thirty migraine without aura patients during the attacks in order to assess the central action on the trigeminal system. Both drugs were effective in reducing headache severity compared to placebo. In the migraine attack an increased area of the R3 component on the pain side was observed; it was suppressed by zolmitriptan, which confirmed its action on the central trigeminal circuits, though the clinical relevance of this effect could be questioned.