Evaluating the relationship between right-to-left shunt and white matter hyperintensities in migraine patients: A systematic review and meta-analysis

The prevalence of positive right to left shunt in migraine patients with and without aura: A new single-center study in China

BACKGROUND

Recently, many studies have reported that there may be association between positive right-to-left shunt (RLS) and migraine, especially Migraine with aura (MA) patients. However, these researches are mostly limited in Western country. And the latest study describing the prevalence of RLS in Chinese patients with migraine was conducted five years ago. It indicated the significant higher rate of positive RLS in MA patients than migraine without aura(MWOA) group. However, no consistent results were observed according to our daily work.

OBJECTIVE

To investigate the prevalence and grade of RLS in migraine patients with and without aura and to evaluate the potential association between positive RLS and migraine with aura.

METHODS

A total of 91 migraine patients were involved, including 57 MWOA patients and 34 MA patients. MWOA and MA were diagnosed according to the International Classification of Headache Disorders, 3rd edition (beta version) (ICHD-3). Contrast transcranial Doppler ultra-sound (cTCD) was used to assess the prevalence of positive RLS, the associations between RLS and presence of aura.

RESULTS

The overall prevalence of RLS in migraine patients was 35.2%. In MA group, 44.1% (15/34) were positive for RLS overall, higher than MWOA group (29.8%,17/57). However, the differences were not significant (P = 0.167). And there were no marked differences in the prevalence of large, middle and small shunt between MA and MWOA patients.

CONCLUSION

Our study suggested MA patients have the slightly higher prevalence of positive RLS than MWOA patients in China. However, there were no significant differences, which was different from the previous studies. Our findings suggested the negative association between the positive RLS and migraine with aura.

Evaluating migraine with typical aura with neuroimaging

Objective

To provide an up-to-date narrative literature review of imaging in migraine with typical aura, as a means to understand better migraine subtypes and aura biology.

Background

Characterizing subtypes of migraine with typical aura and appreciating possible biological differences between migraine with and without aura, are important to understanding the neurobiology of aura and trying to advance personalized therapeutics in this area through imaging biomarkers. One means of doing this over recent years has been the use of increasingly advanced neuroimaging techniques.

Methods

We conducted a literature review of neuroimaging studies in migraine with aura, using a PubMed search for terms 'imaging migraine', 'aura imaging', 'migraine with aura imaging', 'migraine functional imaging' and 'migraine structural imaging'. We collated the findings of the main studies, excluding small case reports and series with n < 6, and have summarized these and their implications for better understanding of aura mechanisms.

Results

Aura is likely mediated by widespread brain dysfunction in areas involving, but not limited to, visual cortex, somatosensory and insular cortex, and thalamus. Higher brain excitability in response to sensory stimulation and altered resting-state functional connectivity in migraine sufferers with aura could have a genetic component. Pure visual aura compared to visual aura with other sensory or speech symptoms as well, may involve different functional reorganization of brain networks and additional mitochondrial dysfunction mediating more aura symptoms.

Conclusion

There is a suggestion of at least some distinct neurobiological differences between migraine with and without aura, despite the shared phenotypic similarity in headache and other migraine-associated symptoms. It is clear from the vast majority of aura phenotypes being visual that there is a particular predisposition of the occipital cortex to aura mechanisms. Why this is the case, along with the relationships between cortical spreading depression and headache, and the reasons why aura does not consistently present in affected individuals, are all important research questions for the future.