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Purpose of ReviewThe goal of this review is to describe the presenting features of fulminant idiopathic intracranial hypertension (IIH) and outline the multimodal approach to its treatment.Recent FindingsVenous sinus stenting may be an appropriate alternative to optic nerve sheath fenestration or cerebrospinal fluid shunting in select patients with fulminant IIH. Prompt surgical intervention maximizes the chance of visual recovery in patients with fulminant IIH.Summary“Fulminant IIH” is defined as intracranial hypertension with no secondary cause, severe vision loss within 4 weeks of symptom onset, and progressive vision loss over days. Rapid recognition of the fulminant phenotype of IIH by emergency department physicians, neurologists, and ophthalmologists is critical. Without appropriate triage and rapid medical and surgical intervention, patients with fulminant IIH are at high risk for profound, permanent vision loss. Prompt surgical intervention with optic nerve sheath fenestration, cerebrospinal fluid shunting, or venous sinus stenting minimizes the chance of poor visual outcome. If a delay is anticipated, serial lumbar punctures or temporary cerebrospinal fluid drainage and medical therapy may forestall irreversible vision loss.

Multiple sclerosis (MS) involves dysregulation of innate immune cells including monocytes, especially in progressive MS. Fatty acid binding proteins (FABP) are essential for fatty acid transport and metabolism in multiple cell types. FABP7, a brain-FABP, maintains metabolic function in astrocytes and neural stem cells, but the effect of FABP7 on monocytes is unknown. Here we find elevated levels of FABP7 in the serum and cerebrospinal fluid of patients with secondary progressive MS. Elevated serum FABP7 levels positively correlate with higher disability scores, brain lesion volumes, and lower brain volumes. FABP7 levels are increased in astrocytes from MS postmortem brain lesion. Mechanistically, in vitro treatment of FABP7 induces CD16, CD80 and IL-1β expression in monocytes via increased glycolysis. FABP7-induced gene expression reflects enhanced inflammation, chemotaxis and glucose metabolism in monocytes. In conclusion, we find that FABP7 induces pro-inflammatory profiles in monocytes, correlates with disability and represents a potential biomarker and therapeutic target for progressive MS. While immune dysregulation is acknowledged as causal for multiple sclerosis (MS), how monocytes contribute to MS etiology is still unclear. Here the authors analyze peripheral blood and cerebrospinal fluid samples as well as brain MRI image data from MS patients to implicate FABP7 in alteration of monocyte glycolysis, and as a potential marker for MS progression.

A 65-year-old man with Waldenström’s macroglobulinemia was evaluated because of an 8-day history of bilateral eye pain and decreased vision. He had decreased visual acuity, dyschromatopsia, visual field loss, a relative afferent pupillary defect, and an abnormal appearance of the optic disk. A diagnosis was made.

We examine the functional characteristics of auditory cortical areas that are sensitive to spatial cues in the human brain, and determine whether they can be dissociated from parietal lobe mechanisms. Three positron emission tomography (PET) experiments were conducted using a speaker array permitting quasi free-field sound presentation within the scanner. Posterior auditory cortex responded to sounds that varied in their spatial distribution, but only when multiple complex stimuli were presented simultaneously, implicating this cortical system in disambiguation of overlapping auditory sources. We also found that the right inferior parietal cortex is specifically recruited in localization tasks, and that its activity predicts behavioral performance, consistent with its involvement in sensorimotor integration and spatial transformation. These findings clarify the functional roles of posterior auditory and parietal cortices, and help to reconcile competing models of auditory cortical organization.

We used functional magnetic resonance adaptation (fMRA) to examine whether intra-voxel functional specificity may be present for first (L1)- and second (L2)-language processing. We examined within- and across-language adaptation for spoken words in English–French bilinguals who had acquired their L2 after the age of 4 years. Subjects listened to words presented binaurally through earphones. In two control conditions (one for each language), six identical words were presented to obtain maximal adaptation. The remaining six conditions each consisted of five words that were identical followed by a sixth word that differed. There were thus a total of eight experimental conditions: no-change (sixth word identical to first five); a change in meaning (different final word in L1); a change in language (final item translated into L2); a change in meaning and language (different final word in L2). The same four conditions were presented in L2. The study also included a silent baseline. At the neural level, within- and across-language word changes resulted in release from adaptation. This was true for separate analyses of L1 and L2. We saw no evidence for greater recovery from adaptation in across-language relative to within-language conditions. While many brain regions were common to L1 and L2, we did observe differences in adaptation for forward translation (L1 to L2) as compared to backward translation (L2 to L1). The results support the idea that, at the lexical level, the neural substrates for L1 and L2 in bilinguals are shared, but with some populations of neurons within these shared regions showing language-specific responses.

Purpose Some patients with idiopathic intracranial hypertension (IIH) have cerebellar tonsillar herniation ≥ 5 mm mimicking Chiari malformation I (CMI), which can result in misdiagnosis and unjustified treatment. Our purpose was to identify IIH patients with tonsillar herniation ≥ 5 mm (IIH TH ) and compare with CMI patients to assess imaging findings that could distinguish the two conditions. Methods Ninety-eight patients with IIH, 81 patients with CMI, and 99 controls were retrospectively assessed. Two neuroradiologists blindly reviewed MR images. IIH TH patients were compared with CMI patients and controls regarding the extent of tonsillar herniation (ETH), bilateral transverse sinus stenosis (BTSS), hypophysis-sella ratio (HSR), and bilateral tortuosity of optic nerve (BTON). Results 13/98 (13.2%) IIH patients had tonsillar herniation ≥ 5 mm (IIH TH ) and were significantly younger and had higher BMI compared with CMI patients and controls. ETH was significantly less in the IIH TH than CMI (6.5 ± 2.4 mm vs. 10.9 ± 4.4 mm; p  < 0.001). BTSS and HSR < 0.5 were more common in IIH TH than CMI ( p  < 0.001 and p  = 0.003, respectively). No differences were seen between CMI and controls. BTON was significantly more common in IIH TH compared to control ( p  = 0.01) but not to the CMI ( p  = 0.36). Sensitivity and specificity to differentiate IIH TH from CMI were 69.2% and 96.1% for BTSS and 69.2% and 75.3% for HSR < 0.5. Conclusion The presence of BTSS and/or HSR < 0.5 in patients with ETH ≥ 5 mm should suggest further evaluation to exclude IIH before considering CMI surgery.

A 23-year-old woman presented with vertigo and vision loss affecting the right eye. Hearing loss and tinnitus of the right ear developed. Fluorescein angiography revealed delayed filling of two arteriolar branches in the right eye. A diagnosis was made.

When hyperbolic partial differential equations arising from convection and wave phenomena are solved using finite differences, a choice must be made on the boundary conditions and numerical boundary scheme (NBS) in order to minimize the reflected error. In this thesis, we attempt to rationalize this choice. We show that the boundary conditions and NBS naturally arise from a characteristic approach applied to a hyperbolic equation and apply these by a flux-vector splitting approach. The eigenvalue spectra of the semi-discretization matrices arising from finite-difference approximations to the linear convection equation, the Maxwell equations, and the Euler equations are computed to evaluate the stability of the overall spatial discretization. Numerical experiments are then used to evaluate the accuracy of each NBS and a first-order non-reflective boundary condition. Through this stability analysis and numerical experiments we demonstrate that the NBS's are effective in minimizing the reflected error and become more effective as the order of the NBS is increased. The results of the numerical experiments also suggest that the NBS provides a lower bound on the reflected error for equations requiring both the NBS and boundary condition. Finally, we find that, under most conditions, the error arising from a first-order non-reflective boundary condition dominates the error arising from the NBS.

Human activities have increased the global circulation of mercury, a potent neurotoxin. Mercury can be converted into methylmercury, which biomagnifies along aquatic food chains and leads to high exposure in fish-eating populations. Here we quantify temporal trends in the ocean-to-land transport of total mercury and methylmercury from fisheries and we estimate potential human mercury intake through fish consumption in 175 countries. Mercury export from the ocean increased over time as a function of fishing pressure, especially on upper-trophic-level organisms. In 2014, over 13 metric tonnes of mercury were exported from the ocean. Asian countries were important contributors of mercury export in the last decades and the western Pacific Ocean was identified as the main source. Estimates of per capita mercury exposure through fish consumption showed that populations in 38% of the 175 countries assessed, mainly insular and developing nations, were exposed to doses of methylmercury above governmental thresholds. Our study shows temporal trends and spatial patterns of Hg transport by fisheries. Given the high mercury intake through seafood consumption observed in several understudied yet vulnerable coastal communities, we recommend a comprehensive assessment of the health exposure risk of those populations.