The autonomic nervous system and the regulation of arterial tone in migraine

Reconceptualizing autonomic function testing in migraine: a systematic review and meta-analysis

BACKGROUND

Autonomic nervous system (ANS) testing has aided in our ability to evaluate autonomic dysfunction in migraine patients. We reviewed the literature in multiple databases which investigate ANS function in migraine patients and healthy subjects.

METHODS

This systematic review and meta-analysis examined the respective deep breathing, Valsalva manoeuvre, orthostatic and isometric challenge results, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-analyses of Observational Studies in Epidemiology (MOOSE) statements.

RESULTS

Seven articles met all inclusion criteria. Fixed-effects meta-analysis showed migraine patients (n = 424), collectively, had lower interictal autonomic test results compared with healthy controls (n = 268). In detail, this was true for the standardized mean difference (g) of deep breathing (g= -0.32; 95% confidence interval (CI) -0.48, -0.16), orthostatic challenge (g= -0.28; 95% CI -0.44, -0.13) and isometric challenge (g= -0.55; 95% CI -0.71, -0.39) and for the difference of means (MD) of the Valsalva ratio (MD = -0.17; 95% CI -0.23, -0.10).

CONCLUSIONS

Interictal ANS dysfunction can be identified in migraine patients when compared to healthy controls. These findings indicate the importance to evaluate ANS function in migraine patients - especially, as migraine-specific prophylactic therapies (such as anti-calcitonin gene-related peptide (CGRP) antibodies) may affect the function of the ANS.

Craniofacial Autonomic Dysfunction in Migraine: Implications for Treatment and Prognosis

BACKGROUND

Craniofacial autonomic signs and symptoms (CASS) are relatively underrecognized in the evaluation of migraine headache. Yet, these features provide insight into diagnostic criterion, therapeutic approaches, and overarching disease burden.

EVIDENCE ACQUISITION

This review aims to summarize relevant literature evaluating autonomic dysfunction, with focus on CASS, in migraine through targeted literature searches in PubMed. Full articles of original data published between 1974 and 2019 were identified using MeSH terms with no search limits.

RESULTS

Although CASS are typically clinically evaluated by subjective patient report, investigational measures of cranial autonomic function have identified marked distinctions between headache attack and attack-free intervals. The presence of CASS during an attack does not differ based on age, sex, or presence of aura. Unilateral CASS may be predictive of longer, more frequent, and/or severe attacks and often co-occur with sensory dysfunction such as allodynia and photophobia. Although limited research has been performed to evaluate targeted therapeutics for migraine with CASS, triptans and onabotulinumtoxinA may demonstrate greater effects in this group.

CONCLUSIONS

Migraine remains a debilitating disorder with significant community-wide impacts, necessitating continued evaluation of contributing features. Consideration of CASS provides important insight into potential treatment approaches and the effectiveness of novel therapeutic interventions aimed at improving overall disease burden. However, further investigation is needed to fully understand primary craniofacial features in migraine, and how these might inform individualized treatment decisions.

Fabrication of polyvinyl alcohol based fast dissolving oral strips of sumatriptan succinate and metoclopramide HCL

Migraine is a throbbing condition, usually associated with nausea and vomiting and requires concurrent administration of anti-migraine along with anti-emetic therapy. The current study was undertaken with an aim to fabricate fast dissolving oral strips (FDOSs) containing Sumatriptan succinate (anti-migraine) and Metoclopramide HCl (anti-emetic) in combination without involving any superdisintegrant. Hydrophilic polymer polyvinyl alcohol (PVA) was used alone with three concentrations of 100, 125, and 150 mg using variable concentrations of glycerol. The solvent casting technique was employed to formulate FDOSs and were evaluated for surface morphology, mechanical properties, surface pH, % moisture content, disintegration time (DT), total dissolving time (TDT), drug contents, and dissolution profile. PVA (150 mg) with 5% glycerol concentration gave best formulation results. FDOSs have exhibited good tensile strength with smooth and uniform surface morphology. DT was ranged from 7.7 to 28 s; while TDT was from 26.4 to 77.6 s. Both polymer and plasticizer concentrations were found to be influencing the characteristics of the strips. Dissolution studies were carried out in distilled water for 15 min and all the formulations have shown released more than 50% drug within first 2 min thereby highlighting the usefulness of FDOSs for the delivery of both drugs in combination significantly. Optimized combination of ingredients was found to be suitable for the formulation of FDOSs for simultaneous delivery of Metoclopramide HCl and Sumatriptan succinate.

Low-frequency facial hemodynamic oscillations distinguish migraineurs from non-headache controls

Background

Surface imaging is a promising, noninvasive approach to assess regional perfusion in craniovascular disorders such as migraine.

Methods

We used optical imaging to examine differences in facial blood volume at baseline and in response to ammonia inhalation (a noxious stimulus), as well as standardized measures of cardiovascular autonomic function, in healthy, non-headache controls (n = 43) and in interictal migraine subjects (n = 22).

Results

Resting facial cutaneous oscillation (FCO) frequency was significantly different in migraine compared to healthy controls. Following ammonia inhalation, healthy controls showed a significant increase in resting FCO frequency, whereas this response was not significant in the migraine group. Standardized autonomic reflex parameters did not differ significantly between study groups, and facial cutaneous activity did not correlate with standardized cardiovascular autonomic reflex parameters, suggesting potentially different regulation.

Conclusions

This approach to the assessment of craniofacial hemodynamic function appears to exhibit differing mechanisms from previously available techniques, and represents a promising new physiological biomarker for the study of craniofacial vascular function in migraine and potentially other craniovascular disorders.

Right-to-left shunts and hormonal therapy influence cerebral vasomotor reactivity in patients with migraine with aura

Patent Foramen Ovale and impaired cerebral hemodynamics were proposed among the pathophysiological mechanisms explaining the increased risk for stroke in patients with Migraine with Aura (MA). Our study aimed at comparing the vasomotor reactivity (VMR) of the anterior and the posterior cerebral circulation in patients with Migraine with Aura, in patients with acute vascular ischemic accidents, and in controls. We hypothesized that VMR in MA patients is preserved in the anterior circulation and reduced in the posterior circulation. We prospectively assessed with Transcranial Doppler the vasomotor reactivity to breath holding of the Middle and Posterior Cerebral Arteries (MCA, PCA) in MA patients, in acute vascular patients and healthy controls. We also evaluated the possible effect of clinical characteristics of MA (attack frequency, aura length or type, disease history), vascular factors and the presence of right-to-left shunt on VMR. Diverging from our hypothesis, MA patients displayed a higher breath-holding index (BHI) than controls in the MCA (1.84±0.47%/s vs 1.53±0.47%/s, p = .001) as well as in the PCA (1.87±0.65%/s vs 1.47±0.44%/s, p < .001). In MA patients, MCA BHI was higher in those with large right-to-left shunts (2.09±0.42 vs 1.79±0.47, p = .046) and lower in those taking estrogens (1.30±0.30%/s vs 1.9±0.45%/s, p = .009). We did not observe an effect of MA characteristics on BHI. The increased BHI in MA patients with large right-to-left shunts could be explained by the vasoactive effect in the cerebral circulation of substances bypassing the deactivating pulmonary filters or by a constitutional trait of the vascular system associating persistent right-to-left shunts and hyper-reactive hemodynamics. Our results discourage the hypothesis that altered hemodynamics contribute to increasing the stroke risk in all MA patients. However, estrogens can lower VMR, curtailing the hemodynamic resources of MA patients.

Parasympathetic Nervous System Dysfunction, as Identified by Pupil Light Reflex, and Its Possible Connection to Hearing Impairment

CONTEXT

Although the pupil light reflex has been widely used as a clinical diagnostic tool for autonomic nervous system dysfunction, there is no systematic review available to summarize the evidence that the pupil light reflex is a sensitive method to detect parasympathetic dysfunction. Meanwhile, the relationship between parasympathetic functioning and hearing impairment is relatively unknown.

OBJECTIVES

To 1) review the evidence for the pupil light reflex being a sensitive method to evaluate parasympathetic dysfunction, 2) review the evidence relating hearing impairment and parasympathetic activity and 3) seek evidence of possible connections between hearing impairment and the pupil light reflex.

METHODS

Literature searches were performed in five electronic databases. All selected articles were categorized into three sections: pupil light reflex and parasympathetic dysfunction, hearing impairment and parasympathetic activity, pupil light reflex and hearing impairment.

RESULTS

Thirty-eight articles were included in this review. Among them, 36 articles addressed the pupil light reflex and parasympathetic dysfunction. We summarized the information in these data according to different types of parasympathetic-related diseases. Most of the studies showed a difference on at least one pupil light reflex parameter between patients and healthy controls. Two articles discussed the relationship between hearing impairment and parasympathetic activity. Both studies reported a reduced parasympathetic activity in the hearing impaired groups. The searches identified no results for pupil light reflex and hearing impairment.

DISCUSSION AND CONCLUSIONS

As the first systematic review of the evidence, our findings suggest that the pupil light reflex is a sensitive tool to assess the presence of parasympathetic dysfunction. Maximum constriction velocity and relative constriction amplitude appear to be the most sensitive parameters. There are only two studies investigating the relationship between parasympathetic activity and hearing impairment, hence further research is needed. The pupil light reflex could be a candidate measurement tool to achieve this goal.

Vagally mediated heart rate variability in headache patients—a systematic review and meta-analysis

Objective

Vagal nerve activity—indexed by heart rate variability (HRV)—has been linked to altered pain processing and inflammation, both of which may underpin headache disorders and lead to cardiovascular disease (CVD). Here we examined the evidence for differences in parasympathetic (vagal) activity indexed by time- and frequency-domain measures of HRV in patients with headache disorders compared to healthy controls (HCs).

Methods

A systematic review and meta-analysis was conducted on studies investigating group differences in vagally mediated HRV (vmHRV) including time- (root-mean-square of successive R-R-interval differences (RMSSD)) and frequency- (high-frequency HRV) domain measures. Studies eligible for inclusion were identified by a systematic search of the literature, based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

Results

Seven studies reporting a total of 10 comparisons of patients with headache disorders (HF-HRV n = 67, RMSSD n = 122) and HCs (HF-HRV n = 64, RMSSD n = 125) were eligible for inclusion. Random-effects meta-analysis revealed a significant main effect on RMSSD ( Z = 2.03, p = 0.04; Hedges’ g = −0.63; 95% CI (−1.24, –0.02); k = 6) and similar pooled effect size estimates for HF-HRV when breathing was controlled ( g = −0.30; 95% CI (−0.69; 0.10)) but not when breathing was not controlled ( g = 0.02; 95% CI (−0.69; 0.74)). Controlling for breathing had no effect on RMSSD.

Conclusion

vmHRV is reduced in patients with headache disorders, findings associated with a medium effect size. Suggestions for future research in this area are provided, emphasizing a need to investigate the impact of headache disorders and commonly comorbid conditions—including mental disorders—as well as the investigation of the risk for CVD in migraine in particular. We further emphasize the need for large-scale studies to investigate HRV as a mechanism mediating the association of migraine and CVD.

Assessment of atrial electromechanical delay in patients with migraine

Evidence suggests that symptoms of migraine are related to the involvement of the autonomic nervous system. Data on atrial conduction system are limited in migraineurs. We aimed to assess atrial electromechanical delay using tissue Doppler imaging (TDI) in patients with migraine. Forty-five migraine patients and age- and sex-matched 26 control subjects were enrolled in the study. All the patients and controls underwent resting surface electrocardiogram (ECG) and TDI. The maximum P-wave duration (Pmax), minimum P-wave duration (Pmin) and P-wave dispersion (Pd) were measured from the 12-lead ECG. Atrial conduction time was determined from the lateral mitral annulus (PA lateral), septal mitral annulus (PA septal), and lateral tricuspid annulus (PA tricuspid) by TDI. Interatrial (PA lateral-PA tricuspid) and intraatrial (PA septal-PA tricuspid) electromechanical delays were calculated. Pd was significantly higher in migraine patients than in controls (p < 0.05), whereas Pmax and Pmin were not different between both groups (p > 0.05). PA lateral and PA septal durations were significantly higher in migraine patients than in controls (p < 0.001 and p < 0.05, respectively). However, PA tricuspid duration was similar between the groups (p > 0.05). Both interatrial and intraatrial conduction times were delayed in migraineurs as compared to the controls (p < 0.001). Interatrial delay and intraatrial delay variables were found as an independent risk factors separately on predicting atrial conduction abnormalities in migraineurs. An interatrial delay of 18 ms and an intraatrial delay of 5 ms were found to be cutoff values in ROC analysis (p < 0.001). This is the first report to provide a hypothetical suggestion that there is an atrial electromechanical delay in patients with migraine.

Panayiotopoulos syndrome: a case series from Turkey

The aim of the study was to evaluate the demographic, clinical, and EEG characteristics of patients with Panayiotopoulos syndrome (PS) and the course of their illness. Thirty-eight patients followed up with a diagnosis of PS between January 2011 and December 2013 were evaluated. We found high rates of personal history of febrile convulsions, breath-holding spells, and family history of febrile convulsions, afebrile convulsion/epilepsy, migraine, and breath-holding spells. Seizures started before the age of eight in 87% of the patients, and the mean age at seizure onset was 4.6 years. Seizures were sleep-related in 81.5%, and autonomic status was seen in a third of the patients. The number of seizures was between 2 and 10 in 66% of the patients. The most common symptoms were ictus emeticus, eye/head deviation, and altered consciousness. Rolandic features were seen in 26% of the patients, and visual symptoms in 5%. Multifocal epileptiform discharges on EEG were identified in 84% of the patients. Two or more antiepileptic drugs were required in only 13% of the patients. Evolution to electrical status epilepticus in sleep and Gastaut-type epilepsy were seen in patients with more than ten seizures. The high rates of febrile convulsions, afebrile convulsions/epilepsy, migraine, and breath-holding spells in the patients and families suggest the importance of genetic factors and, perhaps, a common pathogenesis. However, the high rates of febrile convulsions and breath-holding spells in patients can be related to a misdiagnosis because of the similar symptoms. Despite its disturbing symptoms, PS is a benign epileptic syndrome requiring multiple antiepileptic drug use only in a small proportion of patients.

Sphenopalatine ganglion neuromodulation in migraine: what is the rationale?

OBJECTIVE

The objective of this article is to review the prospect of treating migraine with sphenopalatine ganglion (SPG) neurostimulation.

BACKGROUND

Fuelled by preliminary studies showing a beneficial effect in cluster headache patients, the potential of treating migraine with neurostimulation has gained increasing interest within recent years, as current treatment strategies often fail to provide adequate relief from this debilitating headache. Common migraine symptoms include lacrimation, nasal congestion, and conjunctival injection, all parasympathetic manifestations. In addition, studies have suggested that parasympathetic activity may also contribute to the pain of migraineurs. The SPG is the largest extracranial parasympathetic ganglion of the head, innervating the meninges, lacrimal gland, nasal mucosa, and conjunctiva, all structures involved in migraine with cephalic autonomic symptoms.

CONCLUSION

We propose two possible mechanisms of action: 1) interrupting the post-ganglionic parasympathetic outflow to inhibit the pain and cephalic autonomic symptoms, and 2) modulating the sensory processing in the trigeminal nucleus caudalis. To further explore SPG stimulation in migraineurs as regards therapeutic potential and mode of action, randomized clinical trials are warranted.

[Importance of perimetric differential diagnostics in patients with primary open-angle glaucoma]

Functional deficits in glaucomatous optic neuropathy are, apart from other disturbances in the visual field, typically detected with achromatic perimetry as a well accepted gold standard. With the development of new perimetric devices and strategies (e.g. short wave perimetry, frequency doubling perimetry and flicker perimetry) individually different patterns of scotomas in the different perimetric devices could be recognized. The reasons for this could be a different sensitivity reaction of the ganglion cell subpopulations to an increased intraocular pressure as well as an influence of the underlying systemic diseases. To obtain a differentiated detection of the functional loss in the visual field in glaucoma, the use of different perimetric methods seems to be reasonable and helpful.

Rizatriptan in migraineurs with unilateral cranial autonomic symptoms: a double-blind trial

The objective and background is to confirm in a double-blind, placebo-controlled study the high triptan response rates we had previously reported in an open study in migraine patients with unilateral cranial autonomic symptoms. In this randomized, double-blind, placebo-controlled study 80 migraineurs with unilateral cranial autonomic symptoms were assigned to receive rizatriptan 10 mg wafer or placebo (ratio 1:1) and treated for a single moderate or severe migraine attack. The primary endpoints were pain freedom at 2 h and total migraine freedom at 2 h. Secondary endpoints included pain relief, no associated symptoms and sustained pain freedom or relief. Significantly more patients reported pain freedom at 2 h after taking rizatriptan (54 %) than after placebo (8 %) (therapeutic gain 46 % [28 %; 64 %]; P < 0.001). Similarly, significantly more patients reported total migraine freedom at 2 h after rizatriptan (51 %) than after placebo (8 %) (therapeutic gain 43 % [26 %; 61 %]; P < 0.001). Rizatriptan was also more effective than placebo on most secondary endpoints. We confirm in a placebo-controlled study our previous data suggesting that the presence of unilateral cranial autonomic symptoms in migraineurs predicts a positive response to triptans, probably owing to intense trigeminal peripheral afferent activation which strongly recruits peripheral neurovascular 5-HT1B/1D receptors. Acute and preventive pharmacological trials in migraine should focus also on this subset of migraine patients.

Prevalence of red ear syndrome in juvenile primary headaches

BACKGROUND

Previous studies have suggested a relationship between 'red ear syndrome' (RES) and pediatric migraine. Aims of this study were (i) to assess the frequency, specificity and sensitivity of RES in a population of pediatric migraineurs and (ii) to establish the pathophysiological mechanisms of RES associated with migraine.

METHODS AND RESULTS

A total of 226 children suffering from headache (aged 4-17 years) were enrolled. One hundred and seventy-two (76.4%) were affected by migraine, the remaining 54 (23.6%) by other primary headaches. RES was followed significantly more frequently by migraine (23.3%; p < .0001), and was characterized by high specificity and positive predictive value (96.3 and 95.3%, respectively). According to the univariate statistical analysis, RES showed a statistically significant association with male gender, throbbing quality of the pain, vomiting and phonophobia. It was confirmed by a multivariate stepwise logistic regression model only for the throbbing quality of the pain, vomiting and male gender.

CONCLUSIONS

Our study showed that (i) in children, RES is a highly specific sign for migraine. In addition, the evidence of an association of RES with some migraine features partially provoked by the parasympathetic system supports the hypothesis of a shared pathophysiological background (e.g. via the activation of the trigeminal-autonomic reflex).

The in vivo Effect of VIP, PACAP-38 and PACAP-27 and mRNA Expression of Their Receptors in Rat Middle Meningeal Artery

The parasympathetic nervous system is probably involved in migraine pathogenesis. Its activation releases a mixture of signalling molecules including vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP), which subsequently stimulate VPAC1, VPAC2 and PAC1 receptors. The objective of the present study was to investigate the in vivo effect of VIP, PACAP-27, PACAP-38, the selective VPAC1 agonist ([Lys15, Arg16, Leu27]-VIP(1–7)-GRF(8–27)) and a PAC1 agonist, maxadilan on rat middle meningeal artery (MMA) diameter using the closed cranial window model. Selective antagonists were used for further characterization of the responses. Reverse transcriptase-polymerase chain reaction experiments were also conducted to determine expression of mRNA of PACAP receptors in the MMA. The results showed that VIP, PACAP-38, PACAP-27 and the VPAC1 specific agonist evoked significant dilations with the rank order of potency; VIP = PACAP-38 > PACAP-27 = [Lys15, Arg16, Leu27]-VIP(1–7)-GRF(8–27). Significant inhibition of dilation was only observed for the VPAC1 antagonist PG97–269 on PACAP-38-induced dilation of MMA. The VPAC2 antagonist PG99–465 and PAC1 antagonist PACAP(6–38) did not significantly block VIP- or PACAP-induced dilation. Expression of mRNA of all three receptors was detected in the MMA. In conclusion, the VPAC1 receptor seems to be predominant in mediating MMA dilation. A selective VPAC1 antagonist may be a candidate molecule in the treatment of migraine headache.

Heart rate recovery in migraine and tension-type headache

OBJECTIVE

There are reports proposing that migraine and tension-type headache (TTH) may affect the autonomic nervous system (ANS). Abnormalities in both sympathetic and parasympathetic nervous system have been suggested in migraineurs. However, in TTH, reports on the ANS function are limited and only associated with sympathetic system. Techniques for evaluating parasympathetic activity are more limited when compared with sympathetic function. Hence, the aim of the study was to measure heart rate recovery (HRR), an index of vagal activity, in migraine, TTH, and control subjects.

METHODS

Forty-seven episodic migraine, 10 episodic TTH, 11 chronic TTH, and 25 control subjects underwent exercise tolerance test according to modified Bruce protocol, and HRR at 1 minute and 3 minutes (HRR1 and HRR3) were calculated.

RESULTS

The HRR 1 and 3 were found to be similar in 3 groups of subjects. However, resting heart rate of migraine and chronic TTH were found to be higher than episodic TTH, but not different from the control group.

CONCLUSION

These results suggest that parasympathetic function has not been affected in migraine and TTH patients. However, sympathetic tonus, which is evaluated by resting heart rate, is higher in migraine and chronic TTH than in episodic TTH.

Cardiovascular responses to cognitive stress in patients with migraine and tension-type headache

BACKGROUND

The purpose of this study was to investigate the temporal relationship between autonomic changes and pain activation in migraine and tension-type headache induced by stress in a model relevant for everyday office-work.

METHODS

We measured pain, blood pressure (BP), heart rate (HR) and skin blood flow (BF) during and after controlled low-grade cognitive stress in 22 migraineurs during headache-free periods, 18 patients with tension-type headache (TTH) and 44 healthy controls. The stress lasted for one hour and was followed by 30 minutes of relaxation.

RESULTS

Cardiovascular responses to cognitive stress in migraine did not differ from those in control subjects. In TTH patients HR was maintained during stress, whereas it decreased for migraineurs and controls. A trend towards a delayed systolic BP response during stress was also observed in TTH. Finger BF recovery was delayed after stress and stress-induced pain was associated with less vasoconstriction in TTH during recovery.

CONCLUSION

It is hypothesized that TTH patients have different stress adaptive mechanisms than controls and migraineurs, involving delayed cardiovascular adaptation and reduced pain control system inhibition.

Effect of sympathetic and parasympathetic mediators on the release of calcitonin gene-related peptide and prostaglandin E from rat dura mater, in vitro

Although not without controversy, an influence of the autonomic nervous system in headache is a matter for current debate. A possible contact site of autonomic and sensory nerves is the dura mater, where they form a dense network accompanying blood vessels. We investigated interactions between autonomic and nociceptive fibres by measuring release of calcitonin gene-related peptide (CGRP) and prostaglandin E2 (PGE2) from the dura mater, in vitro. The parasympathomimetic agent carbachol did not change basal release of CGRP or PGE2, whereas it diminished release induced by a mixture of inflammatory mediators. Norepinephrine did not change induced release of CGRP or PGE2, nor basal release of CGRP. However, basal release of PGE2 was enhanced by norepinephrine, and this enhancement was reduced by serotonin through 5-HT(1D) receptors. We conclude that sympathetic transmitters may control nociceptor sensitivity via increased basal PGE2 levels, a possible mechanism to facilitate headache generation. Parasympathetic transmitters may reduce enhanced nociceptor activity.

Profil autonomique des patients migraineux

OBJECT

Dysfunction of autonomic nervous system (ANS) is implicated in the genesis and persistence of migraine. The objective of this study was to compare autonomic nervous system (ANS) profile of migraineurs during headache-free periods to a group of normal subjects based on cardio-vascular reactivity.

METHODS

Patients with migraine according to the criteria of IHS 2004 were selected for the study. After a 30 min resting blood pressure (BP), the following standard tests were performed: deep-breathing (DB), hand grip (HG) of 15 s and 3 min, valsalva maneuver, echo stress, (ES) and tilt test (TT). Results were compared to 44 normal subjects, age similar, 37 female, (84.1%) using the Student test, with P < 0.005 as significant.

RESULTS

Thirty-two patients (27 female (84.38%), 16-51 years, mean 40.41 +/- 7.8) were studied. Twenty-two patients (69%) had systolic blood pressure below 94 mmHg and 25 patients (78%) had diastolic blood pressure below 60 mmHg. Compared to normal, migraineurs exhibited a significantly higher vagal response (P < 0.001) and a significantly lower alpha sympathetic response, central by using ES as well as peripheral by using HG of 3 min (P < 0.001).

CONCLUSIONS

Autonomic cardiovascular reactivity of patients with migraine showed a vagal hyperactivity and a deficiency of the alpha sympathetic system. This leads to further studies with new therapeutical approaches.

Decreased vasoreactivity to right cerebral hemisphere pressure in migraine without aura: a near-infrared spectroscopy study

OBJECTIVE

Several studies have reported changes in cerebrovascular reactivity during the interictal period of migraine. To characterize mechanisms of migraine, we compared changes in total haemoglobin (THbl) and regional oxygen saturation (rSO(2)) of the right and left frontal lobes in response to intracranial pressure changes during the interictal period of migraine.

METHODS

Twelve right-handed migraineurs without aura and twelve age- and sex-matched healthy volunteers were asked to perform a head-down maneuver to increase intracranial venous pressure. Initial THbl was designated as 1.0, and all subsequent THbl measurements, which was proportional to the change in cerebral blood flow, were expressed as a value relative to this baseline.

RESULTS

The head-down maneuver resulted in a significantly smaller increase in right-sided THbl in migraineurs when compared to volunteers (migraineurs, -0.1+/-0.04; volunteers, 30+/-13; P=0.027), but there was no significant difference in left-sided THbl when comparing migraineurs and volunteers. Further, the head-down maneuver produced a significantly smaller increase in right-sided THbl than in left-sided THbl in migraineurs (right side, -0.1+/-0.04; left side, 0.35+/-0.08; P<0.0001), but produced a significantly greater increase in right-sided THbl than in left-sided THbl in volunteers (right side, 30+/-13; left side, 0.44+/-0.13; P=0.030). The head-down maneuver resulted in a smaller decrease in right-sided rSO(2) in migraineurs when compared to volunteers (migraineurs, -4.1+/-2.2%; volunteers, -16+/-9.1%), but produced a significantly greater decrease in left-sided rSO(2) in migraineurs when compared to volunteers (migraineurs, -1.3+/-1.1%; volunteers, 2.8+/-0.63%; P=0.0037).

CONCLUSIONS

These data indicate that pressure-related vasoreactivity is suppressed in the right hemisphere of migraineurs during the interictal period.

SIGNIFICANCE

The suppression of vasoreactivity in the right hemisphere might be related to the pathogenesis of migraine.

Impairment of parasympathetic baroreflex responses in migraine patients

OBJECTIVES

The aim of this study was to assess baroreflex regulation of the heart rate and blood vessels in migraine patients in comparison with healthy controls.

METHODS

In 30 migraine patients who were in a headache-free phase, aged 34 +/- 2 years, and 30 healthy controls, aged 34 +/- 3 years, we applied oscillatory neck suction at 0.1 Hz to assess the sympathetic modulation of the heart and blood vessels and at 0.2 Hz to assess the effect of parasympathetic stimulation on the heart. Breathing was paced at 0.25 Hz. Electrocardiographic RR-intervals, blood pressure and respiration were continuously recorded. Responses to the baroreflex stimulations were assessed as the changes in power of the RR-interval and blood pressure fluctuations at the relevant stimulating frequency from the baseline values.

RESULTS

Systolic and diastolic blood pressure responses to the 0.1 Hz neck suction pressure were not significantly different between the patients and controls. The RR-interval oscillatory response to 0.2 Hz neck suction was significantly less (P < 0.05) in the migraine patients (4.45 +/- 0.27 ln ms2) compared with the controls (5.48 +/- 0.36 ln ms2).

CONCLUSION

These results suggest that baroreflex-mediated cardiovagal responses are reduced in migraine patients. However, the sympathetic-mediated baroreflex control of the blood vessels is intact in the migraine patients. The autonomic nervous system may have a role in the pathophysiology of migraine.

Preliminary experience with dexmedetomidine in the treatment of cyclic vomiting syndrome

Cyclic vomiting syndrome (CVS) is a chronic, recurrent disorder of unknown etiology characterized by episodes of nausea and vomiting lasting hours or days and separated by symptom-free intervals of weeks to months. Although several different therapeutic regimens have been suggested for CVS, there remains no standard, effective regimen. In many cases, management of vomiting episodes includes the use of potent sedatives that induce prolonged durations of sedation and sleep. Dexmedetomidine is an alpha(2) adrenergic agonist with an increased specificity for the alpha(2) versus the alpha(1) receptor when compared with clonidine. Several physiologic effects have been demonstrated with dexmedetomidine including sedation, anxiolysis, analgesia, and blunting of the sympathetic nervous system. We report, for the first time, successful use of dexmedetomidine to treat CVS in 3 pediatric-aged patients. Potential mechanisms for its efficacy and future potential as a therapeutic agent for CVS are discussed.

Relationship between pain and autonomic phenomena in headache and other pain conditions

Involvement of the (efferent) autonomic nervous system in the generation of pain is ongoing matter of debate. Based on clinical and experimental observations, there are good arguments that the sympathetic nervous system may be involved in pain following trauma, with and without nerve lesion, at an extremity, such as in complex regional pain syndrome type I and II. However, the mechanisms involved are in many cases still unclear. In various types of headache there is no convincing evidence that the sympathetic nervous system is involved in the generation of pain, although these pains may be accompanied by considerable autonomic reactions which are dependent on activity in sympathetic neurons. Migraine and headaches with autonomic symptoms are accompanied by autonomic reactions which are dependent on activity in cranial parasympathetic neurons. Whether parasympathetic neurons innervating cranial blood vessels are involved in activation or sensitization of trigemino-vascular afferents is discussed and needs experimental verification.

Comparative study of anxiety, depression, somatization, functional disability, and illness attribution in adolescents with chronic fatigue or migraine

OBJECTIVE

To compare adolescents with migraine, unexplained profound chronic fatigue of >6 months duration, and normal school controls on measures of anxiety, depression, somatization, functional disability, and illness attribution.

METHODS

Adolescents referred to Children's Hospital and Regional Medical Center for behavioral treatment of migraine (n = 179) or evaluation of chronic fatigue (n = 97) were compared with a group of healthy controls of similar age and sex from a middle school (n = 32). Subjects completed the Spielberger State-Trait Anxiety Inventory-Trait Form, the Children's Depression Inventory, the Childhood Somatization Inventory, and estimated the number of school days missed in the past 6 months because of illness. Migraine and fatigued subjects completed an illness attribution questionnaire.

RESULTS

Subjects in the 3 groups were 56% to 70% female and ranged from 11 years old to 18 years old with a mean age of 14.0 +/- 2.0. Forty-six of the 97 chronically fatigued adolescents met 1994 Centers for Disease Control and Prevention (CDC) criteria for chronic fatigue syndrome (CDC-CFS), while 51 had idiopathic chronic fatigue syndrome (I-CFS) that did not meet full CDC criteria. Adolescents with migraine had significantly higher anxiety scores than those with I-CFS or controls and higher somatization scores than controls. Adolescents with CDC-CFS had significantly higher anxiety scores than those with I-CFS or controls, and higher depression and somatization scores than all other groups. There were significant differences between all groups for school days missed with CDC-CFS more than I-CFS more than migraine more than controls. Parents of adolescents with unexplained I-CFS had significantly lower attribution scores relating illness to possible psychological or stress factors than parents of adolescents with CDC-CFS or migraine.

CONCLUSIONS

Adolescents referred to an academic center for evaluation of unexplained chronic fatigue had greater rates of school absenteeism than adolescents with migraine or healthy controls. Those meeting CDC-CFS criteria had higher anxiety scores than controls and higher depression and somatization scores than migraineurs or controls. Parents of adolescents with I-CFS were less likely to endorse psychological factors as possibly contributing to their symptoms than parents of adolescents with CDC-CFS or migraine.

Cranial and peripheral interictal vascular changes in migraine patients

As migraine is associated with an increased risk for ischaemic stroke and peripheral vasospastic disorders, it was hypothesized that interictal vascular changes may be present in migraine patients. Using ultrasound and applanation tonometry, the cardiovascular properties of migraine patients were compared with those of matched control subjects. Vascular parameters of the carotid arteries, cardiac output and systemic vascular resistance did not differ between both groups. Right temporal artery diameter was larger in migraine patients (mean difference 101 micro m; 95% confidence interval (CI) 9/194 micro m; P = 0.033). At the brachial artery, migraine patients displayed a smaller distension (difference -24 micro m; 95% CI -45/-4 micro m; P = 0.021) and a decreased compliance (difference -0.025 mm2/kPa; 95% CI -0.047/-0.003 mm2/kPa; P = 0.024). Thus, migraine patients display an increased peripheral arterial stiffness. The presence of these interictal vascular changes suggests that migraine might be part of a more generalized vascular disorder.

The effect of rizatriptan, ergotamine, and their combination on human peripheral arteries: a double-blind, placebo-controlled, crossover study in normal subjects

AIMS

To compare the peripheral vasoconstrictor effects of ergotamine, rizatriptan, and their combination, in normal subjects.

METHODS

This was a double-blind, four-way, crossover study. Sixteen young male volunteers, selected as responders to the vasoconstrictor effect of 0.5 mg ergotamine i.v., were administered 10 mg oral rizatriptan, 0.25 mg i.v. ergotamine, 10 mg oral rizatriptan+0.25 mg i.v. ergotamine, and placebo. The vasoconstrictor effect on peripheral arteries was measured with strain gauge plethysmography up to 8 h after dosing. The 8 h assessment period was divided into two 4 h intervals to assess the immediate (0-4 h) vs sustained effect (4-8 h) of treatment.

RESULTS

For the 0-4 h interval, the decreases in peripheral systolic blood pressure gradients were: placebo (-1 mmHg [95% CI: -3, 1])<rizatriptan (-5 mmHg [95% CI: -7, -3])<ergotamine (-15 mmHg [95% CI: -16, -13])=rizatriptan+ergotamine (-15 mmHg [95% CI: -17, -13]). For the 4-8 h interval, the decreases were: placebo (-5 mmHg [95% CI: -8, -3])=rizatriptan (-8 mmHg [95% CI: -11, -5])<ergotamine (-26 mmHg [95% CI: -29, -24])=rizatriptan+ergotamine (-28 mmHg [95% CI: -31, -26]).

CONCLUSIONS

In normal subjects, rizatriptan 10 mg orally had only a small transient vasoconstrictor effect on peripheral arteries compared with the sustained and more pronounced effect of 0.25 mg i.v. ergotamine. Furthermore, rizatriptan exerted no additional effect on ergotamine-induced constriction of peripheral arteries when the two drugs were given in combination.

The abdominal brain and enteric nervous system

Conventional medical treatment for neurologic disorders such as epilepsy, migraine, and autism focuses on the brain. Although standard medical treatment is often helpful, the underlying causes of these disorders are not well understood. Furthermore, some individuals respond poorly or not at all to regular medicine. Evidence is accumulating in the medical literature that the enteric nervous system (ENS)-that part of the nervous system associated with the alimentary canal-also plays a role in these disorders. Historically, the concept of an autonomous abdominal nervous system was advocated by Byron Robinson, Johannis Langley, and Edgar Cayce. The work of these three prominent historical figures is considered along with modem view-points on the abdominal nervous system. Complementary therapies that address the nervous system of the abdomen have potential as useful adjuncts to conventional treatment for certain neurologic disorders.

Evaluation of neurocardiac signals in pediatric patients with cyclic vomiting syndrome through power spectral analysis of heart rate variability

OBJECTIVE

To investigate autonomic regulation of neurocardiac signals in pediatric patients with cyclic vomiting syndrome (CVS).

METHODS

Fourteen patients with CVS, ages 3 to 16 years, were screened to eliminate any underlying cause for their symptoms, although 11 of the 14 patients had a history of migraine in the immediate family. Analysis of autonomic regulation was accomplished through power spectral analysis of the beat-to-beat heart rate variability signal. Data from affected patients were compared with data from 38 control subjects, ages 5 to 16 years, by a one-way analysis of variance. A measure of sympathovagal balance was obtained by computing a ratio of power in the low-frequency band (0. 02-0.15 Hz) to the power in the high-frequency band (0.15-0.4 Hz).

RESULTS

Pediatric patients with CVS have an elevated sympathetic modulation of the sinus node as represented by the low frequency/high frequency ratio (1.45 +/- 0.42 in patients vs 0.89 +/- 0.29 in healthy control subjects, P <.001).

CONCLUSIONS

The patients with CVS we studied have an autonomic imbalance with enhanced sympathetic and diminished parasympathetic vagal modulation of the heart.

Cerebral syncope: loss of consciousness associated with cerebral vasoconstriction in the absence of systemic hypotension

Transcranial Doppler (TCD) ultrasonography done during head-upright tilt induced neurocardiogenic syncope has demonstrated that cerebral vasoconstriction occurs concomitant with (or precedes) loss of consciousness. This article demonstrates evidence that cerebral blood flow changes alone (vasoconstriction), in the absence of systemic hypotension, may result in syncope. Five patients (4 men, 1 woman; mean age 41 +/- 17 years) with recurrent unexplained syncope were evaluated by use of an upright tilt table test for 45 minutes with or without an infusion of low dose isoproterenol. TCDoppler ultrasonography was used to assess middle cerebral artery systolic velocity (Vs); diastolic velocity (Vd); mean velocity (Vm); and pulsatility index (PI = Vs = Vd/Vmean). Syncope occurred in five patients during the baseline tilt and in one patient during isoproterenol infusion. During tilt induced syncope, at an average mean arterial pressure of 89 +/- 16 mmHg, TCD sonography showed a 2% +/- 10% increase in systolic velocity; a 51% +/- 27% decrease in diastolic velocity; and a 131% +/- 87% increase in pulsatility index. One patient underwent continuous electroencephalographic recording during tilt, which demonstrated diffuse slow wave activity (indicating cerebral hypoxia) at the time of syncope concomitant with the aforementioned TCD changes in the absence of systemic hypotension. These findings reflect an increase in cerebrovascular resistance secondary to arteriolar vasoconstriction distal to the insonation point of the middle cerebral artery, that occurred concomitant with loss of consciousness and in the absence of systemic hypotension. We conclude that in some individuals abnormal baroreceptor responses triggered during orthostatic stress may result in a derangement of cerebral autoregulation leading to cerebral vasoconstriction with resultant cerebral hypoxia in the absence of systemic hypotension.

Power spectral analysis of heart rate and diastolic blood pressure variability in migraine with and without aura

Autonomic function in migraineurs during headache-free periods was studied by means of cardiovascular reflexes and power spectral analysis of heart rate and diastolic blood pressure variability. We examined 56 patients: 37 suffering from migraine without aura and 19 from migraine with aura. Cardiovascular responses to the tilt test and Valsalva manoeuvre showed a normal function of the overall baroreceptor reflex arc. Normal heart rate responses to Valsalva manoeuvre and deep breathing suggested an intact parasympathetic function. Power spectral analysis of both heart rate and diastolic blood pressure variability in basal conditions and during orthostatic test showed similar sympathovagal interactions modulating cardiovascular control in migraine patients and in controls.

Role of nitric oxide in the physiopathology of pain

Many painful disorders, including joint dysfunctions such as rheumatoid arthritis (RA) or temporomandibular joint disorders (TMD), are associated with hyperthermia of the overlying skin. The same is true of certain intractable chronic pain conditions, such as chronic orofacial pain, which may be associated with TMD. We suggest that this skin hyperthermia, caused by regional vasodilation, is induced by extravascular nitric oxide (NO). Extravascular NO can be produced in the affected joint by osteoblasts, chondrocytes, and macrophages, by mechanical stimulation of endothelial cells, or by stimulated neurons. In view of a strong correlation between pain and skin hyperthermia in these disorders, and the evidence that NO enhances the sensitivity of peripheral nociceptors, we also suggest that at least this kind of pain is associated with excessive local level of NO. This hypothesis can be verified by dynamic area telethermometry, assessing the effect of NO on the sympathetic nervous function. This mechanism, which is in line with the general role of NO as a mediator between different organ systems, also may be relevant to any pain associated with enhanced immune response. Clinical implications of the proposed mechanism are discussed.