Continuous-time statistics and generalized relaxation equations

Using two simple examples, the continuous-time random walk as well as a two state Markov chain, the relation between generalized anomalous relaxation equations and semi-Markov processes is illustrated. This relation is then used to discuss continuous-time random statistics in a general setting, for statistics of convolution-type. Two examples are presented in some detail: the sum statistic and the maximum statistic

The differential diagnosis of chronic daily headaches: an algorithm-based approach

Chronic daily headaches (CDHs) refers to primary headaches that happen on at least 15 days per month, for 4 or more hours per day, for at least three consecutive months. The differential diagnosis of CDHs is challenging and should proceed in an orderly fashion. The approach begins with a search for “red flags” that suggest the possibility of a secondary headache. If secondary headaches that mimic CDHs are excluded, either on clinical grounds or through investigation, the next step is to classify the headaches based on the duration of attacks. If the attacks last less than 4 hours per day, a trigeminal autonomic cephalalgia (TAC) is likely. TACs include episodic and chronic cluster headache, episodic and chronic paroxysmal hemicrania, SUNCT, and hypnic headache. If the duration is ≥4 h, a CDH is likely and the differential diagnosis encompasses chronic migraine, chronic tension-type headache, new daily persistent headache and hemicrania continua. The clinical approach to diagnosing CDH is the scope of this review

Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant

Migraine research comes of age in the 21st century

Paroxysmal Cerebral Disorder

Migraine research comes of age in the 21st century

Paroxysmal Cerebral Disorder

Migraine and MTHFR C677T genotype in a population-based sample.

Contains fulltext : 50540.pdf (publisher's version ) (Closed access)OBJECTIVE: Migraine with aura is associated with increased risk of stroke. The MTHFR C677T genotype has been associated with increased risk of migraine in selected clinical samples and with elevated homocysteine, a risk factor for stroke. We assessed the association of the MTHFR C677T variant with migraine and the mediating effect of cardiovascular risk factors and metabolic markers of genotype status. METHODS: We compared adult migraineurs with aura (MA; n = 187), without aura (MO; n = 226), and nonmigraineurs (n = 1,212) from the population-based Genetic Epidemiology of Migraine study. RESULTS: Compared with the wild-type genotype, the T/T genotype was associated with increased odds of MA (odds ratio [OR], 2.05; 95% confidence interval, 1.2-3.4; p < 0.006), with a trend of increasing numbers of T alleles (OR, 1.40; 95% confidence interval, 1.1-1.8; p < 0.007). ORs were slightly attenuated after adjusting for homocysteine. INTERPRETATION: Risk of MA is associated with MTHFR C674T homozygosity, independent of other cardiovascular risk factors

Migraine, depression, and brain volume The AGES-Reykjavik Study

OBJECTIVE: To examine the joint association of migraine headache and major depressive disorder on brain volume in older persons without dementia. METHODS: Participants (n = 4,296, 58% women) from the population-based Age, Gene/Environment Susceptibility–Reykjavik Study were assessed for migraine headache in 1967–1991 (age 51 years [range 33–65]) according to modified International Classification of Headache Disorders–II criteria. In 2002–2006 (age 76 years [range 66–96]), lifetime history of major depressive disorder (depression) was diagnosed according to DSM-IV criteria, and full-brain MRI was acquired, which was computer postprocessed into total brain volume (TBV) (gray matter [GM], white matter [WM], white matter hyperintensities) and CSF volume for each study subject. We compared brain tissue volumes by headache categories with or without depression using linear regression, adjusting for intracranial volume and other factors. RESULTS: Compared with the reference group (no headache, no depression) TBV and WM and GM volumes were smaller in those with both migraine and depression (TBV −19.2 mL, 95% confidence interval [CI] −35.3, −3.1, p = 0.02; WM −12.8 mL, CI −21.3, −4.3, p = 0.003; GM −13.0 mL, CI −26.0, 0.1, p = 0.05) but not for those with migraine alone (TBV 0.4 mL, WM 0.2 mL, GM 0.6 mL) or depression alone (TBV −3.9 mL, WM −0.9 mL, GM −2.9 mL). CONCLUSIONS: Reporting both migraine and major depressive disorder was associated with smaller brain tissue volumes than having one or neither of these conditions. Migraineurs with depression may represent a distinct clinical phenotype with different long-term sequelae. Nonetheless, the number of subjects in the current study is relatively small and these findings need to be confirmed in future studies