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Migraine: will the circle (of Willis) be unbroken?

 

REPORT FROM THE AMERICAN ACADEMY OF NEUROLOGY (AAN) ANNUAL MEETING, PHILADELPHIA PA, APRIL 26-MAY 3, 2014 – It has been suggested that circle of Willis variants may contribute to the pathogenesis of migraine as a result of decreased or more variable regional cerebral blood flow (Cucchiara et al. Med Hypotheses 2008;70:860-87).

This has been investigated in the Anatomy and Cerebral Hemodynamic Evaluation of Migraine (ACHE-M) controlled study of migraine patients with and without aura (Cucchiara et al. PLoS One 2013;8:e71007).

An incomplete circle of Willis on MR angiography was significantly more common in migraine with aura compared to controls (32% vs. 13%); while migraine without aura had intermediate results (21%). An incomplete circle of Willis was more common in males compared to females (79% vs. 59%). However, an analysis of 156 subjects found no significant differences in global or regional cerebral blood flow on perfusion MRI, although there was greater asymmetry in hemispheric cerebral blood flow in migraine patients. The authors speculated that circle of Willis variants may allow for relative ischemia during situations of increased metabolic demand.

As a follow-up to that study, Cucchiara and colleagues have now examined the relationship between circle of Willis variants, cerebral blood flow and white matter hyperintensities (WMH) (AAN 2014; abstract P6.199). A high WMH load was more common in migraine than controls (23% vs. 17%), although differences were not significant. Increased WMH were not generally associated with lower cerebral blood flow, but migraine patients with aura and a high WMH load did appear to have lower cerebral blood flow.

Two prior studies using MR angiography have also reported an association between an incomplete circle of Willis and migraine (Bugnicourt et al. Headache 2009;49:879-886; Cavestro et al. Can J Neurol Sci 2011;38:494-499). Further investigations are needed to determine if circle of Willis variants contribute to the increased risk of ischemic stroke in migraine patients.

Guest Reviewer: Dr. Daniel Selchen, Head of Neurology, St. Michael’s Hospital, Toronto, Canada

Smaller studies in MS: vitamin D, fatigue and dietary salt

 

REPORT FROM THE AMERICAN ACADEMY OF NEUROLOGY (AAN) ANNUAL MEETING, PHILADELPHIA PA, APRIL 26-MAY 3, 2014 – For over 50 years, solar radiation and vitamin D have been implicated in the pathogenesis of MS (Acheson et al. Acta Psychiatr Scand Suppl 1960;35:132-147), in large part due to the latitude effect. However, the relevance of serum 25(OH)D levels and the virtues of vitamin D supplementation remain controversial. Read More

Traumatic brain injury in sports a focus of annual meeting

 

REPORT FROM THE AMERICAN ACADEMY OF NEUROLOGY (AAN) ANNUAL MEETING, PHILADELPHIA PA, APRIL 26-MAY 3, 2014 – There has been a growing recognition in the U.S. of the problem of sports-related traumatic brain injury (TBI), notably in children and adolescents. An analysis of the U.S. National Electronic Injury Surveillance database found  that the incidence of TBI-related Emergency Department visits increased 62% over a 10-year period, with 248,418 visits recorded in 2009 (Gilchrist J. MMR Weekly 2011;60:1337-1342). The estimated incidence of TBI visits was 298 per 100,000 population.

The highest TBI rates were seen in males aged 10-19 years. Long-term consequences of TBI include chronic traumatic encephalopathy, chronic post-concussion syndrome, chronic neurocognitive impairment, post-traumatic cognitive impairment or dementia, and post-traumatic parkinsonism. Read More

Abnormal cerebral activation in conversion disorder

 

REPORT FROM THE AMERICAN ACADEMY OF NEUROLOGY (AAN) ANNUAL MEETING, PHILADELPHIA PA, APRIL 26-MAY 3, 2014 – Conversion disorder, or the development of neurological symptoms originating in psychological factors, has undergone a shift in recent years, with neurologists playing a larger role in what was once the exclusive domain of psychiatrists.

When characterized as hysterical neurosis, the emphasis was on the psychogenic basis of symptoms. However, in the current iteration of the Diagnostic and Statistical Manual (DSM-5), the importance of changes in the functioning of the nervous system has been underlined. Thus, Conversion Disorder may also be considered as a Functional Neurological Symptom Disorder in DSM-V, and a critical component of diagnosis is a neurological exam that excludes organic signs and identifies positive signs of a functional disorder. One challenge, however, is that there are numerous clinical signs for functional neurological symptoms, but few of these have been validated (for a systematic review see Daum et al. J Neurol Neurosurg Psychiatry 2014;85:180-190). Read More