Altered Cardiovascular Reactivity to Mental Stress But Not to Cold Pressure Test in Migraine

(Headache 2010;50:133‐137) Objectives.— This study assessed cardiovascular reactivity to mental stress and cold pressure test in migraineurs and controls. It compared the cardiovascular reactivity between patients with migraine with aura and patients with migraine without aura. Background.— Several studies have assessed the autonomic nervous system functioning and cardiovascular responses to stressor stimuli in migraine. Cold pressure test and sustained attention tasks are distinct forms of induced stress. It is still unknown if patients with migraine have distinct patterns of response to sustained attention tasks and cold pressure test, since no previous studies have evaluated the cardiovascular responses to these 2 distinct types of stress in the same population of migraine patients. Methods.— Two distinct protocols were used to induce cardiovascular reactivity. Mental stress was induced by using a Stroop test card, a procedure involving the maintenance of the attention control. The other protocol was the cold pressure test. The blood pressure and heart rate were digitally recorded in rest and test phases. The mean elevation and the variance of blood pressure and heart rate were compared between groups. Results.— Patients with migraine had higher rest systolic blood pressure and lower heart rate induced by mental stress than controls. There were no differences between migraineurs and controls with cold pressure test. There were no differences between migraineurs with and without aura. Conclusion.— There was a significantly different pattern of cardiovascular reactivity between migraineurs and controls with mental stress but not with cold pressure test. Distinct central nervous system structures are involved in these 2 types of stress. A distinct pattern of activation of the prefrontal cortex—periaqueductal gray matter circuit in migraine may explain a singular autonomic reactivity to mental stress in this disease.     

Autonomic Nervous System Dysfunction in Common Migraine

SYNOPSIS
Common migraine has been related to both dysfunction of the autonomic nervous system (A.N.S.) in the regulation of cerebral vasomotor tonicity and to neurotic and depressive tendencies. In the present study 86 normal healthy controls and 50 patients with common migraine were studied in order to determine whether tonic or phasic central autonomic nervous system dysfunction was concomitant with migraine during a headache-free, medication-free interval. pupillometry was employed to measure relevant parameters of sympathetic and parasympathetic activity at rest and during the cold pressor test. Concomitantly, measurements of neuroticism, anxiety and depression were also obtained.
Migraineurs were not identifiably different from controls with respect to tonic sympathetic or parasympathetic activity nor were they distinguishable on measures of supranuclear inhibition. However, 70% of migraineurs manifested phasic hyposympathetic activity in response to the cold pressor test. These migraineurs also demonstrated more neurotic and depressive tendencies. The physiological dysfunction was shown to differentiate the groups of migraineurs after personality variables were statistically controlled by a covariance multiple regression analysis.
Results of the study are discussed in relationship to cerebral blood flow and permeability of the cerebral vasculature.     

Migraine: a chronic sympathetic nervous system disorder

OBJECTIVES: To determine the degree of diagnostic and clinical similarity between chronic sympathetic nervous system disorders and migraine. BACKGROUND: Migraine is an episodic syndrome consisting of a variety of clinical features that result from dysfunction of the sympathetic nervous system. During headache-free periods, migraineurs have a reduction in sympathetic function compared to nonmigraineurs. Sympathetic nervous system dysfunction is also the major feature of rare neurological disorders such as pure autonomic failure and multiple system atrophy. There are no known reports in the medical literature, however, comparing sympathetic nervous system function in individuals with migraine, pure autonomic failure, and multiple system atrophy. METHODS: A detailed review of the literature was performed to compare the results of a wide variety of diagnostic tests and clinical signs that have been described in these 3 heretofore unrelated disorders. RESULTS: The data indicate that migraine shares significant diagnostic and clinical features with both pure autonomic failure and multiple system atrophy, yet represents a distinct subtype of chronic sympathetic dysfunction. Migraine is most similar to pure autonomic failure in terms of reduced supine plasma norepinephrine levels, peripheral adrenergic receptor supersensitivity, and clinical symptomatology directly related to sympathetic nervous system dysfunction. The peripheral sympathetic nervous system dysfunction is much more severe in pure autonomic failure than in migraine. Migraine differs from both pure autonomic failure and multiple system atrophy in that migraineurs retain the ability, although suboptimal, to increase plasma norepinephrine levels following physiological stressors. CONCLUSIONS: The major finding of the present study is that migraine is a disorder of chronic sympathetic dysfunction, sharing many diagnostic and clinical characteristics with pure autonomic failure and multiple system atrophy. However, the sympathetic nervous system dysfunction in migraine differs from pure autonomic failure and multiple system atrophy in that occurs in an anatomically intact system. It is proposed that the sympathetic dysfunction in migraine relates to an imbalance of sympathetic co-transmitters. Specifically, it is suggested that a migraine attack is characterized by a relative depletion of sympathetic norepinephrine stores in conjunction with an increase in the release of other sympathetic cotransmitters such as dopamine, prostaglandins, adenosine triphosphate, and adenosine. An enhanced understanding of the sympathetic dysfunction in migraine may help to more effectively diagnose, prevent, and/or treat migraine and other types of headache.     

The vestibulo-collic reflex is abnormal in migraine

Interictal evoked central nervous system responses are characterized in migraineurs by a deficit of habituation, at both cortical and subcortical levels. The click-evoked vestibulo-collic reflex (VCR) allows the assessment of otolith function and an oligosynaptic pathway linking receptors in the saccular macula to motoneurons of neck muscles. Three blocks of 75 averaged responses to monaural 95-dB normal hearing level 3-Hz clicks were recorded over the contracted ipsilateral sternocleidomastoid muscle in 25 migraineurs between attacks and 20 healthy subjects, without vestibular symptoms. Amplitudes, raw and corrected for baseline electromyography, were significantly smaller in migraine patients. Whereas in healthy volunteers the VCR habituated during stimulus repetition (-4.96% +/- 14.3), potentiation was found in migraineurs (4.34% +/- 15.3; P = 0.04). The combination with a reduced mean amplitude does not favour vestibular hyperexcitability as an explanation for the habituation deficit in migraine, but rather an abnormal processing of repeated stimuli in the reflex circuit.     

Correlation between abnormal brain excitability and emotional symptomatology in paediatric migraine

We investigated a possible correlation between brain excitability in children with migraine and tension-type headache (TTH) and their behavioural symptomatology, assessed by using the Child Behaviour Checklist (CBCL). The mismatch negativity (MMN) and P300 response were recorded in three successive blocks to test the amplitude reduction of each response from the first to the third block (habituation). MMN and P300 habituation was significantly lower in migraineurs and TTH children than in control subjects (two-way anova : P  < 0.05). In migraineurs, but not in TTH patients, significant positive correlations between the P300 habituation deficit and the CBCL scores were found ( P  < 0.05), meaning that the migraineurs with the most reduced habituation showed also the worst behavioural symptomatology. To the best of our knowledge, this is the first study showing a correlation between neurophysiological abnormality and emotional symptomatology in migraine, suggesting a role of the latter in producing the migrainous phenotype.     

Central Nervous System Underpinnings of Sensory Hypersensitivity in Migraine: Insights from Neuroimaging and Electrophysiological Studies

Whereas considerable data have been generated about the pathophysiology of pain processing during migraine attacks, relatively little is known about the neural basis of sensory hypersensitivity. In migraine, the term “hypersensitivity” encompasses different and probably distinct pathophysiological aspects of sensory sensitivity. During attacks, many patients have enhanced sensitivity to visual, auditory and/or olfactory stimuli, which can enhance headache while interictally, migraineurs often report abnormal sensitivity to environmental stimuli that can cause nonpainful discomfort. In addition, sensorial stimuli can influence and trigger the onset of migraine attacks. The pathophysiological mechanisms and the origin of such sensitivity (individual predisposition to develop migraine disease or consequence of repeated migraine attacks) are ill understood. Functional neuroimaging and electrophysiological studies allow for noninvasive measures of neuronal responses to external stimuli and have contributed to our understanding of mechanisms underlying sensory hypersensitivity in migraine. The purpose of this review is to present pivotal neuroimaging and neurophysiological studies that explored the basal state of brain responsiveness to sensory stimuli in migraineurs, the alterations in habituation and attention to sensory inputs, the fluctuations of responsiveness to sensory stimuli before and during migraine attacks, and the relations between sensory hypersensitivity and clinical sensory complaints.     

Contact heat evoked potentials and habituation measured interictally in migraineurs

Background

A lack of habituation of different evoked potential modalities in migraine patients in-between attacks has been suggested.

Methods

This study investigates cortical response after painful stimuli evaluated by contact heat evoked potentials (CHEPs) and quantitative sensory testing (QST) during the migraine-free interval. We enrolled 22 migraine patients and 22 healthy subjects.

Results

Cortical potentials after contact heat stimulation of the cheeks and the volar forearm at a temperature of 51°C showed significantly reduced A-δ-amplitudes in patients and healthy controls. When the subjects’ attention was drawn to an arithmetic task, a partial lack of habituation of amplitude could be seen in migraine patients. QST did not show any difference between migraineurs and controls.

Conclusion

Our findings can be primarily deemed to demonstrate that patients and healthy controls show significantly lower amplitudes while performing the calculation task. Without performing the calculation task we could not show the expected lack of habituation in migraineurs. Yet, while performing the calculation task our results partly suggest that hypothesis.     

Cerebrovascular response to repetitive visual stimulation in interictal migraine with aura

Cortical hypersensitivity and absent habituation to different stimuli have been observed in migraine patients. These features might also be transmitted to the cerebral vasoreactivity, but results are conflicting so far. Transcranial Doppler ultrasound (TCD) was used to assess cerebral blood flow velocity (CBFV) changes in the middle (MCA) and posterior cerebral arteries (PCA) in relation to repetitive checkerboard visual stimulation. Stimulation consisted of 10 consecutive cycles, each comprising 10 s stimulation and 10 s rest. TCD recordings were analysed using stimulus-related averaging algorithm. Data of 19 interictal migraineurs with aura were compared to those of 19 headache-free healthy volunteers. The CBFV increase in PCA and in MCA during visual stimulation was significantly larger and steeper in migraineurs than in controls (P = 0.017 and P = 0.005). The response in PCA remained stable over the 10 stimulation cycles, both in migraineurs and in controls. The response in MCA was stable only in migraineurs. In controls it decreased over the last 5 stimulation cycles compared with the first 5 cycles (P = 0.04). Migraineurs with aura exhibit a larger cerebrovascular response to repetitive visual stimulation compared to headache-free subjects. A reduced adaptation to environmental stimuli in migraine is suggested, since there was no habituation in migraineurs in contrast to healthy controls.     

Elevated audiovisual temporal interaction in patients with migraine without aura

Background

Photophobia and phonophobia are the most prominent symptoms in patients with migraine without aura. Hypersensitivity to visual stimuli can lead to greater hypersensitivity to auditory stimuli, which suggests that the interaction between visual and auditory stimuli may play an important role in the pathogenesis of migraine. However, audiovisual temporal interactions in migraine have not been well studied. Therefore, our aim was to examine auditory and visual interactions in migraine.

Methods

In this study, visual, auditory, and audiovisual stimuli with different temporal intervals between the visual and auditory stimuli were randomly presented to the left or right hemispace. During this time, the participants were asked to respond promptly to target stimuli. We used cumulative distribution functions to analyze the response times as a measure of audiovisual integration.

Results

Our results showed that audiovisual integration was significantly elevated in the migraineurs compared with the normal controls (p < 0.05); however, audiovisual suppression was weaker in the migraineurs compared with the normal controls (p < 0.05).

Conclusions

Our findings further objectively support the notion that migraineurs without aura are hypersensitive to external visual and auditory stimuli. Our study offers a new quantitative and objective method to evaluate hypersensitivity to audio-visual stimuli in patients with migraine.     

Autonomic dysfunction in migraineurs

Objective.—To evaluate autonomic function and sympathovagal balance in migraineurs and healthy controls.
Background.—The pathophysiology of migraine is still largely unknown. An imbalance of the autonomic nervous system could explain many of the clinical manifestations of the disorder.
Materials and Methods.—We undertook autonomic function tests in 17 women suffering from migraine (8 with aura) (average age 36 ± 7 years) and 16 healthy women (average age 34 ± 7 years). Autonomic nervous system studies consisted of tests of sympathetic function (the quantitative sudomotor axon reflex test, beat-to-beat blood pressure responses to the Valsalva maneuver, sustained handgrip, cold pressor test, and head-up tilt and tests of parasympathetic function (heart rate responses to deep breathing and the Valsalva maneuver). The data from the tilt test were further evaluated by time-frequency analysis (Wigner distribution).
Results.—Subjects with migraine with aura had a smaller increase of mean blood pressure during phase IV of the Valsalva maneuver ( P <0.05) and a lower blood pressure increment during the handgrip test ( P =0.08); their time-frequency distribution showed reduced power at the nonrespiratory frequencies in the R-R interval at both minutes 1 ( P <0.03) and 5 ( P <0.04) of head-up tilt. Sympathovagal balance (a ratio of spectral power of nonrespiratory frequency variations in blood pressure to that at respiratory frequency variations in the R-R interval) was significantly increased in migraineurs, both with and without aura, by 10 minutes of head-up tilt.
Conclusion.—Subjects with migraine with aura had resting supine sympathetic hypofunction and intact parasympathetic function. With head-up tilt, sympathovagal balance is increased. The dynamic alterations in autonomic nervous system function may contribute to the development of aura in patients with migraine.     

Visual, long-latency auditory and brainstem auditory evoked potentials in migraine: relation to pattern size, stimulus intensity, sound and light discomfort thresholds and pre-attack state

We aimed to estimate primary sensory evoked potential (EP) amplitude, amplitude-intensity functions and habituation in migraine patients compared with healthy control subjects and to investigate the possible relation to check size, sound and light discomfort thresholds, and the time to the next attack. Amplitudes of cortical visual evoked potentials (VEP, check size 8' and 33'), cortical long latency auditory evoked potential (AEP NIP1; 40, 55 and 70 dB SL tones) and brainstem auditory evoked potential (BAEP wave IV-V; 40, 55 and 65 dB SL clicks) were recorded and analysed in a blind and balanced design. The difference between the response to the first and the second half of the stimulus sequence was used as a measure of habituation. Twenty-one migraine patients (16 women and five men, mean age 39.3 years, six with aura, 15 without aura) and 22 sex- and age-matched healthy control subjects were studied (18 women and four men, mean age 39.5 years). Low sound discomfort threshold correlated significantly with low levels of BAEP wave IV-V amplitude habituation (r = -0.30, P = 0.05). VEP an AEP amplitudes, habituation, and amplitude-intensity function (ASF) slopes did not differ between groups when ANOVA main factors were considered. Control group VEP habituation was found for small check stimuli (P = 0.04), while potentiation was observed for medium sized checks (P = 0.02). The eight migraine patients who experienced headache within 24 h after the test tended to have increased BAEP wave IV-V ASF slopes (P = 0.08). This subgroup did also have a significant VEP habituation to small checks (P = 0.04). No correlation was found between different modalities. These results suggest that: (i) VEP habituation/potentiation state and brainstem activatio state may depend on the attack-interval cycle in migraine; (ii) VEP habituation/ potentiation may depend on spatial stimulus frequency; (iii) phonophobia (and possibly photophobia) may depend more on subcortical (brainstem) function than on cortical mechanisms; (iv) low cortical preactivation in migraine could not be confirmed; (v) EP habituation and ASF analysis may reflect sensory modality-specific, not generalized, central nervous system states in migraine and healthy control subjects.     

Sumatriptan in migraine with unilateral cranial autonomic symptoms: an open study

OBJECTIVE: To investigate the response to sumatriptan in migraineurs with unilateral cranial autonomic symptoms such as lacrimation, eye redness, eyelid edema, nasal congestion, and rhinorrhea. BACKGROUND: Given the potential large-scale recruitment of peripheral neurovascular 5-HT1B/1D receptors consequent to the activation of the trigeminal autonomic reflex in such patients, the presence of unilateral cranial autonomic symptoms may predict a positive response to sumatriptan. METHODS: Seventy-two consecutive migraineurs with unilateral cranial autonomic symptoms were given sumatriptan 50-mg tablets to treat 1 migraine attack and were asked to record their clinical response to the drug at different time points. End points were pain-relief and pain-free response at 1 and 2 hours. RESULTS: Pain relief was reported by 47 patients (65.3%) at 1 hour and by 59 (81.9%) at 2 hours. Pain-free response was reported by 22 patients (30.6%) at 1 hour and by 44 (61.1%) at 2 hours. Responsiveness to sumatriptan did not correlate with the type or number of unilateral cranial autonomic symptoms, demographic characteristics, prophylactic treatments, use of contraceptives, or concomitant tension-type headache. CONCLUSIONS: Migraineurs with unilateral cranial autonomic symptoms seem to respond to sumatriptan better than other migraineurs. The presence of unilateral cranial autonomic symptoms may predict a positive response to the triptans.     

Lack of cold pressor test-induced effect on visual-evoked potentials in migraine

In patients with migraine, the various sensory stimulation modalities, including visual stimuli, invariably fail to elicit the normal response habituation. Whether this lack of habituation depends on abnormal activity in the sub-cortical structures responsible for processing incoming information as well as nociception and antinociception or on abnormal cortical excitability per se remains debateable. To find out whether inducing tonic pain in the hand by cold pressure test (CPT) alters the lack of visual-evoked potential (VEP) habituation in migraineurs without aura studied between attacks we recorded VEPs in 19 healthy subjects and in 12 migraine patients during four experimental conditions: baseline; no-pain (hand held in warm water, 25°C); pain (hand held in cold water, 2–4°C); and after-effects. We measured P100 amplitudes from six blocks of 100 sweeps, and assessed habituation from amplitude changes between the six sequential blocks. In healthy subjects, the CPT decreased block 1 VEP amplitude and abolished the normal VEP habituation (amplitude decrease to repeated stimulation) in patients with migraine studied between attacks; it left block 1 VEP amplitude and abnormal VEP habituation unchanged. These findings suggest that the interictal cortical dysfunction induced by migraine prevents the cortical changes induced by tonic painful stimulation both during pain and after pain ends. Because such cortical changes presumably reflect plasticity mechanisms in the stimulated cortex, our study suggests altered plasticity of sensory cortices in migraine. Whether this abnormality reflects abnormal functional activity in the subcortical structures subserving tonic pain activation remains conjectural.     

Interictal potentiation of passive "oddball" auditory event-related potentials in migraine

We have studied habituation of the P3a component of the passive "oddball" auditory event-related potential which reflects automatic processing of a "novel" stimulus in 24 patients suffering from migraine without aura and in 21 healthy volunteers. Three blocks of responses to 160 standard and to 40 novel tones were sequentially averaged at Cz and analyzed for latencies and peak-to-peak amplitudes. Latencies of components N1 and P2 elicited by standard tones and of components N1, P2, N2, and P3a elicited by novel tones were not significantly different between sequential blocks or between subject groups, nor were mean N1-P2 amplitudes. The N2-P3a amplitude tended to be lower in migraine, but not significantly so. The most striking result in migraineurs was a significant potentiation of N2-P3a in successive blocks, contrasting with an habituation in controls. Our previous evoked- and event-related potential studies and the present one suggest that deficient habituation, or even potentiation, represents interictally a fundamental dysfunction of cortical information processing in migraine, which might increase energy demands and play a role in etiopathogenesis.     

Are migraineurs hypersensitive? A test of the stimulus processing disorder hypothesis

The concept of hypersensitivity in migraineurs was advanced mainly on the basis of studies on information processing in which increased amplitudes and reduced habituation in cortical evoked and event related potentials were found in migraine sufferers. The present investigation examined whether migraineurs exhibit hypersensitivity within three different experimental paradigms and various non electrocortical response parameters. Samples of 24 migraine, 19 tension-type headache sufferers, and 24 normal controls were compared regarding their subjective estimation of intensity and discomfort due to visual and acoustical stimuli. Subjects also participated in an experiment using the eyeblink startle response paradigm. In a last experimental task the Stroop test was applied. The trait variables emotionality, arousal, and extraversion were also measured. None of the experimental tasks revealed the predicted hypersensitivity of migraineurs in relation to the control samples. The series of experiments was conducted a second time with half of the participants in order to replicate the findings. The conclusions remained the same. The results of earlier studies on cortical processing can not be interpreted as demonstrating general hypersensitivity in the sense of a dispositional trait in migraine afflicted individuals irrespective of the involved response system.     

Median nerve somatosensory evoked potentials in migraine.

Eur J Neurol. 2002;9:227-232.
In visual evoked potential studies, habituation during stimulus repetition with the same stimulus at a constant intensity has been found to be abnormal in migraineurs between attacks. The purpose of this study was to investigate habituation of somatosensory evoked potentials (SEPs) and the effects of migraine on them. Eighty-five subjects were included in the study: 30 healthy volunteers (HVs) and 55 migraineurs [30 with migraine without aura (MO), 25 with migraine with aura (MA)]. During continuous stimulation at 3 Hz, four blocks of 100 responses were sequentially averaged of Erb's point (N9), cervical (N13), and cortical (N20) median nerve SEPs. Mean amplitude changes in the second, third and fourth blocks are expressed as percentages of the first block. There was habituation to N13 and N20 in the second, third and fourth blocks in HVs. In the migraine groups, there was no habituation; on the contrary, potentiation was found. This potentiation was statistically significant only in the second blocks for N13 (MO P   =  0.007, MA P   =  0.01 versus HVs). However, in both migraineur groups, the rate of N20 potentiations was statistically significant versus that in HVs for all blocks (all P < 0.05). It is concluded that whilst physiological habituation occurs in HVs for cervical and cortical SEPs, in migraine patients there is an interictal deficit of habituation of this sensory modality.
Comment: This interesting study confirms the lack of habituation to repetitive stimuli reported in migraineurs between attacks and extends this finding to somatosensory evoked potentials using median nerve stimulation. One might speculate that migraineurs lack a protective mechanism which modulates both cervical and cortical sensory inputs. DSM     

Digital plethysmographic responses to auditory stimuli in patients with vibration disease.

Digital plethysmographic responses to auditory stimuli in 15 healthy men and 82 patients with vibration disease were analyzed in order to clarify the functional conditions of autonomic nervous system in this disease. The auditory stimuli given to healthy men caused a rapid decrease in the amplitude of the plethysmograms. After cessation of the auditory stimuli the decreased amplitude recovered to the control value within 30 sec. In the patients with vibration disease, however, the recovery of the decreased amplitude was delayed. The plethysmographic changes in the patients with vibration disease were divided into 4 types: normal (N), intermediate (I), delayed (D) and poor response (P) types. Each type of I, D and P was altered to type N by treatments consisting of therapeutic exercises, hot spring cures and so on. All healthy men showed type N. There were no significant differences between the time courses of the recovery of the plethysmographic changes and the amplitudes of the plethysmograms before the auditory stimuli. The results obtained seem to indicate that the autonomic nervous system in the patient with vibration disease is in disorder, and that the digital plethysmography with auditory stimuli is instrumental to detect the functional changes in the autonomic nervous system.     

Migraine is Associated With Altered Processing of Sensory Stimuli

Migraine is associated with derangements in perception of multiple sensory modalities including vision, hearing, smell, and somatosensation. Compared to people without migraine, migraineurs have lower discomfort thresholds in response to special sensory stimuli as well as to mechanical and thermal noxious stimuli. Likewise, the environmental triggers of migraine attacks, such as odors and flashing lights, highlight basal abnormalities in sensory processing and integration. These alterations in sensory processing and perception in migraineurs have been investigated via physiological studies and functional brain imaging studies. Investigations have demonstrated that migraineurs during and between migraine attacks have atypical stimulus-induced activations of brainstem, subcortical, and cortical regions that participate in sensory processing. A lack of normal habituation to repetitive stimuli during the interictal state and a tendency towards development of sensitization likely contribute to migraine-related alterations in sensory processing.     

Changes in visual-evoked potential habituation induced by hyperventilation in migraine

Hyperventilation is often associated with stress, an established trigger factor for migraine. Between attacks, migraine is associated with a deficit in habituation to visual-evoked potentials (VEP) that worsens just before the attack. Hyperventilation slows electroencephalographic (EEG) activity and decreases the functional response in the occipital cortex during visual stimulation. The neural mechanisms underlying deficient-evoked potential habituation in migraineurs remain unclear. To find out whether hyperventilation alters VEP habituation, we recorded VEPs before and after experimentally induced hyperventilation lasting 3 min in 18 healthy subjects and 18 migraine patients between attacks. We measured VEP P100 amplitudes in six sequential blocks of 100 sweeps and habituation as the change in amplitude over the six blocks. In healthy subjects, hyperventilation decreased VEP amplitude in block 1 and abolished the normal VEP habituation. In migraine patients, hyperventilation further decreased the already low block 1 amplitude and worsened the interictal habituation deficit. Hyperventilation worsens the habituation deficit in migraineurs possibly by increasing dysrhythmia in the brainstem-thalamo-cortical network.     

Acupuncture in migraine: investigation of autonomic effects

OBJECTIVE: A dysregulation of the autonomic nervous system is discussed as a pathogenetic factor in migraine. As acupuncture has been shown to exhibit considerable autonomic effects, we tested whether the clinical effects of acupuncture in migraine prophylaxis are mediated by changes of the autonomic regulation. METHODS: We simultaneously monitored changes of heart-rate variability (HRV) as an index of cardiac autonomic control and clinical improvement during an acupuncture treatment in 30 migraineurs. HRV was derived from spectral analysis of the electrocardiogram, which was performed before, during, and after the first and the last session of a series of 12 acupuncture sessions. Migraineurs were randomly allocated to 2 groups receiving either verum acupuncture (VA) or sham acupuncture (SA) treatment. RESULTS: Across the combined VA and SA groups, the clinical responders (with at least 50% reduction of migraine attacks) exhibited a decrease of the low-frequency (LF) power of HRV in the course of the treatment, which was not be observed in patients without clinical benefit. VA compared with SA induced a stronger decrease of high-frequency power. The mode of acupuncture, however, did not have an impact on the LF component of HRV or the clinical outcome. DISCUSSION: The data indicate, that VA and SA acupuncture might have a beneficial influence on the autonomic nervous system in migraineurs with a reduction of the LF power of HRV related to the clinical effect. This might be due to a reduction of sympathetic nerve activity. VA and SA induce different effects on the high-frequency component of HRV, which seem, however, not to be relevant for the clinical outcome in migraine.