Objective: To perform a meta-analysis of migraine biomarkers in cerebrospinal fluid (CSF) and of corresponding blood concentrations. Methods: We conducted a systematic search for studies that measured biochemical compounds in CSF of chronic or episodic migraineurs and non-headache controls. Subsequent searches retrieved studies with blood measurements of selected CSF biomarkers. If a compound was assessed in three or more studies, results were pooled in a meta-analysis with standardised mean differences (SMD) as effect measures. Results: Sixty-two compounds were measured in 40 CSF studies. Most important results include: increased glutamate (five studies, SMD 2.22, 95% CI: 1.30, 3.13), calcitonin gene-related peptide (CGRP) (three studies, SMD: 3.80, 95% CI: 3.19, 4.41) and nerve growth factor (NGF) (three studies, SMD: 6.47, 95% CI: 5.55, 7.39) in chronic migraine patients and decreased b-endorphin (b-EP) in both chronic (four studies, SMD: -1.37, 95% CI: -1.80, -0.94) and interictal episodic migraine patients (three studies, SMD: -1.12, 95% CI: -1.65, -0.58). In blood, glutamate (interictal) and CGRP (chronic, interictal and ictal) were increased and b-EP (chronic, interictal and ictal) was decreased. Conclusions: Glutamate, b-EP, CGRP and NGF concentrations are altered in CSF and, except for NGF, also in blood of migraineurs. Future research should focus on the pathophysiological roles of these compounds in migraine.

ObjectiveTo evaluate pharmacologic treatment options for visual snow and to report prevalence of comorbid diseases.MethodsMedical charts of patients with a diagnosis of visual snow at the neurology outpatient clinic were reviewed on prescribed medication, and comorbid migraine, tinnitus, and psychiatric conditions including depression and anxiety.ResultsFrom 2007 to 2018, 58 patients were diagnosed with visual snow. Comorbid migraine was present in 51.7% of patients, lifetime depression in 41.4%, and lifetime anxiety in 44.8%. Lamotrigine was prescribed most frequently (26/58) and resulted in partial remission of symptoms in 5/26 (19.2%). No patients reported complete remission. Adverse events occurred in 13/26 (50.0%) patients. None of the other prescribed drugs (valproate [n = 7], topiramate [n = 4], acetazolamide [n = 2], flunarizine [n = 1]) led to improvement except for topiramate in one patient, who discontinued, however, because of adverse events.ConclusionsOf medication prescribed (lamotrigine, valproate, acetazolamide, flunarizine), only lamotrigine afforded some improvement in a small minority of patients. Migraine, depression, anxiety, and tinnitus were common comorbid diseases.Classification of evidenceThis study provides Class IV evidence that for some patients with visual snow, lamotrigine resulted in partial remission of symptoms.

Patients with visual snow see countless small dots in the entire visual field. These dots are continuously present, and patients often describe it as seeing "TV static" [1]. Diagnosis is made after exclusion of secondary causes of pan-field visual disturbances, such as lesions in the visual pathway and retina. Most patients report additional visual symptoms such as (i) palinopsia, (ii) enhanced entoptic

Semantic knowledge graphs composed of information integrated from multiple and varying sources can assist researchers in identifying potential disease biomarkers.

The endocannabinoid system has emerged as a crucial regulator of synaptic communication in the CNS (1-3). Dysregulation of this system is implicated in various neurological and psychiatric disorders, such as neuroinflammation, stroke, brain trauma, anxiety, and depression (4-8). The endocannabinoid system consists of endogenous lipid messengers (endocannabinoids) that activate two distinct cannabinoid (CB) (CB 1 and CB 2 ) receptors and the en-

Migraine is a common headache disorder characterized by often-severe headaches that may be preceded or accompanied by a variety of visual symptoms. Although a typical migraine aura is not difficult to diagnose, patients with migraine may report several other visual symptoms, such as prolonged or otherwise atypical auras, “visual blurring”, “retinal migraine”, “ophthalmoplegic migraine”, photophobia, palinopsia, and “visual snow”. Here, we provide a short overview of these symptoms and what is known about the relationship with migraine pathophysiology. For some symptoms, the association with migraine is still debated; for other symptoms, recent studies indicate that migraine mechanisms play a role.

Headache disorders, characterized by recurrent headache, are among the most common disorders of the nervous system. Primary headache disorders are by definition not the result of any other underlying disease or process. In this chapter the current status of cerebrospinal fluid (CSF) research and applications for clinical practice for the three main primary headaches - migraine, cluster headache, and tension-type headache - will be described. Primary headaches are clinically diagnosed disorders, with typically normal routine CSF measurements. Research in these headaches has been focused on identifying pathophysiologic pathways with a wide array of measured molecules. CSF research in the headache field is still in the discovery phase, with most studies performed in migraine and with unreplicated findings for most of the identified molecules. From a clinical standpoint it would be of great value if CSF biomarkers could be used as disorder-specific biomarkers for difficult primary headache cases, or to predict treatment responsiveness or risk for headache chronification. These applications are currently not yet feasible. For future research into CSF biomarkers for primary headache disorders, two different strategies should be employed: hypothesis-driven and nonhypothesis-driven biochemical research, to show new avenues for treatment strategies and develop prediction models for clinical use.

IntroductionMetabolic profiling of cerebrospinal fluid (CSF) is a promising technique for studying brain diseases. Measurements should reflect the in vivo situation, so ex vivo metabolism should be avoided.ObjectiveTo investigate the effects of temperature (room temperature vs. 4 °C), centrifugation and ethanol, as anti-enzymatic additive during CSF sampling on concentrations of glutamic acid, glutamine and other endogenous amines.MethodsCSF samples from 21 individuals were processed using five different protocols. Isotopically-labeled alanine, isoleucine, glutamine, glutamic acid and dopamine were added prior to sampling to trace any degradation. Metabolomics analysis of endogenous amines, isotopically-labeled compounds and degradation products was performed with a validated LC–MS method.ResultsThirty-six endogenous amines were quantified. There were no statistically significant differences between sampling protocols for 31 out of 36 amines. For GABA there was primarily an effect of temperature (higher concentrations at room temperature than at 4 °C) and a small effect of ethanol (lower concentrations if added) due to possible degradation. O-phosphoethanolamine concentrations were also lower when ethanol was added. Degradation of isotopically-labeled compounds (e.g. glutamine to glutamic acid) was minor with no differences between protocols.ConclusionMost amines can be considered stable during sampling, provided that samples are cooled immediately to 4 °C, centrifuged, and stored at − 80 °C within 2 h. The effect of ethanol addition for more unstable metabolites needs further investigation. This was the first time that labeled compounds were used to monitor ex vivo metabolism during sampling. This is a useful strategy to study the stability of other metabolites of interest.Electronic supplementary materialThe online version of this article (10.1007/s11306-018-1333-0) contains supplementary material, which is available to authorized users.