Migraine and white matter hyperintensities: The ARIC MRI study

OBJECTIVE: Migraine is associated with white matter hyperintensities (WMH) cross-sectionally, but its effect on WMH progression is uncertain. METHODS: Participants in the Atherosclerosis Risk in Communities cohort study (n = 10,924) completed a standardized headache questionnaire between 1993 and 1995. A subset of participants (n = 1,028) received 2 MRIs 8 to 12 years apart: once at the time of headache ascertainment, and again from 2004 to 2006. WMH were quantified using both a visually graded score (0-9) and semiautomated volumetric analysis. Linear and logistic regression models adjusted for age, sex, and other vascular risk factors were constructed. RESULTS: Individuals who had migraine without aura were cross-sectionally associated with an 87% greater odds of having a WMH score ≥3 than individuals without headache (adjusted odds ratio = 1.87; 95% confidence interval [CI]: 1.04, 3.37). Participants with migraine had an average of 2.65 cm(3) more WMH than those without headache (95% CI: 0.06, 5.24). However, there was no significant difference in WMH progression over the study period between individuals with and without migraine (1.58 cm(3) more progression for individuals with migraine compared to those without; 95% CI: -0.37, 3.53). CONCLUSION: Migraine is associated with WMH volume cross-sectionally but not with WMH progression over time. This suggests that the association between migraine and WMH is stable in older age and may be primarily attributable to changes occurring earlier in life, although further work is needed to confirm these findings

Primary radiation damage in silicon from the viewpoint of a machine learning interatomic potential

Characterization of the primary damage is the starting point in describing and predicting the irradiation-induced damage in materials. So far, primary damage has been described by traditional interatomic potentials in molecular dynamics simulations. Here, we employ a Gaussian approximation machine-learning potential (GAP) to study the primary damage in silicon with close to ab initio precision level. We report detailed analysis of cascade simulations derived from our modified Si GAP, which has already shown its reliability for simulating radiation damage in silicon. Major differences in the picture of primary damage predicted by machine-learning potential compared to classical potentials are atomic mixing, defect state at the heat spike phase, defect clustering, and recrystallization rate. Atomic mixing is higher in the GAP description by a factor of two. GAP shows considerably higher number of coordination defects at the heat spike phase and the number of displaced atoms is noticeably greater in GAP. Surviving defects are dominantly isolated defects and small clusters, rather than large clusters, in GAP's prediction. The pattern by which the cascades are evolving is also different in GAP, having more expanded form compared to the locally compact form with classical potentials. Moreover, recovery of the generated defects at the heat spike phase take places with higher efficiency in GAP. We also provide the attributes of the new defect cluster that we had introduced in our previous study. A cluster of four defects, in which a central vacancy is surrounded by three split interstitials, where the surrounding atoms are all 4-folded bonded. The cluster shows higher occurrence in simulations with the GAP potential. The formation energy of the defect is 5.57 eV and it remains stable up to 700 K, at least for 30 ps. The Arrhenius equation predicts the lifetime of the cluster to be 0.0725 mu s at room temperature.Peer reviewe

CANOMAD Presenting as Bilateral Sixth Nerve Palsies

A 67-year-old man reported 1 day of binocular horizontal diplopia associated with 1 week of bilateral periorbital pain, worse in the right eye. He felt otherwise well without any constitutional symptoms. Four days prior, he had undergone a partial right nephrectomy for grade II papillary renal cell carcinoma. Visual acuity was 20/20 in each eye, and the remainder of his ophthalmic examination was normal except for mildly limited abduction bilaterally, with a 16-prism diopter esotropia in primary gaze. Brain MRI, acetylcholine receptor antibodies, and thyroid-stimulating hormone level were normal

The Case-Control Study in Neuro-Ophthalmology

A case-control study is an observational epidemiologic study design that compares the prevalence of a risk factor or treatment exposure between 2 groups: those with a particular disease or condition of interest (cases), and a similar group that is at risk for this disease or condition but does not have it (controls). Because cases can be pooled across different centers and years of study, case-control studies are particularly well suited for studying rare diseases, which is frequently the case in neuro-ophthalmology. However, their inherently retrospective nature makes it challenging to establish temporality and to distinguish between association and causation. They are also susceptible to recall,selection, and confounding biases. It is therefore important for neuro-ophthalmologists to be familiar with the principles of case-control study design to critically appraise the neuro-ophthalmic epidemiologic literature. In this article, presented as a companion to Lin et al's" Idiopathic Intracranial Hypertension and Anemia: A Matched Case-Control Study"(1) and Rueløkke et al's "Optic Disc Drusen Associated Anterior Ischemic Optic Neuropathy: Prevalence of Comorbidities and Vascular Risk Factors" (2), we review the basics of case-control study design and highlight several common pitfalls in case-control studies for readers to consider when evaluating new studies

On Modified Burr XII-Inverse Weibull Distribution: Development, Properties, Characterizations and Applications

A flexible lifetime distribution with increasing, decreasing, inverted bathtub and modified bathtub hazard rate called Modified Burr XII-Inverse Weibull (MBXII-IW) is introduced and studied. The density function of MBXII-IW is exponential, left-skewed, right-skewed and symmetrical shaped.  Descriptive measures on the basis of quantiles, moments, order statistics and reliability measures are theoretically established. The MBXII-IW distribution is characterized via different techniques. Parameters of MBXII-IW distribution are estimated using maximum likelihood method. The simulation study is performed to illustrate the performance of the maximum likelihood estimates (MLEs). The potentiality of MBXII-IW distribution is demonstrated by its application to real data sets: serum-reversal times and quarterly earnings