Slow perceptual processing at the core of developmental dyslexia: a parameter-based assessment of visual attention

The cognitive causes as well as the neurological and genetic basis of developmental dyslexia, a complex disorder of written language acquisition, are intensely discussed with regard to multiple-deficit models. Accumulating evidence has revealed dyslexics’ impairments in a variety of tasks requiring visual attention. The heterogeneity of these experimental results, however, points to the need for measures that are sufficiently sensitive to differentiate between impaired and preserved attentional components within a unified framework. This first parameter-based group study of attentional components in developmental dyslexia addresses potentially altered attentional components that have recently been associated with parietal dysfunctions in dyslexia. We aimed to isolate the general attentional resources that might underlie reduced span performance, i.e., either a deficient working memory storage capacity, or a slowing in visual perceptual processing speed, or both. Furthermore, by analysing attentional selectivity in dyslexia, we addressed a potential lateralized abnormality of visual attention, i.e., a previously suggested rightward spatial deviation compared to normal readers. We investigated a group of high-achieving young adults with persisting dyslexia and matched normal readers in an experimental whole report and a partial report of briefly presented letter arrays. Possible deviations in the parametric values of the dyslexic compared to the control group were taken as markers for the underlying deficit.The dyslexic group showed a striking reduction in perceptual processing speed (by 26% compared to controls) while their working memory storage capacity was in the normal range. In addition, a spatial deviation of attentional weighting compared to the control group was confirmed in dyslexic readers, which was larger in participants with a more severe dyslexic disorder. In general, the present study supports the relevance of perceptual processing speed in disorders of written language acquisition and demonstrates that the parametric assessment provides a suitable tool for specifying the underlying deficit within a unitary framework.     

Fibroblast growth factor signaling in the developing neuroendocrine hypothalamus

Fibroblast growth factor (FGF) signaling is pivotal to the formation of numerous central regions. Increasing evidence suggests FGF signaling also directs the development of the neuroendocrine hypothalamus, a collection of neuroendocrine neurons originating primarily within the nose and the ventricular zone of the diencephalon. This review outlines evidence for a role of FGF signaling in the prenatal and postnatal development of several hypothalamic neuroendocrine systems. The emphasis is placed on the nasally derived gonadotropin-releasing hormone neurons, which depend on neurotrophic cues from FGF signaling throughout the neurons’ lifetime. Although less is known about neuroendocrine neurons derived from the diencephalon, recent studies suggest they also exhibit variable levels of dependence on FGF signaling. Overall, FGF signaling provides a broad spectrum of cues that ranges from genesis, cell survival/death, migration, morphological changes, to hormone synthesis in the neuroendocrine hypothalamus. Abnormal FGF signaling will deleteriously impact multiple hypothalamic neuroendocrine systems, resulting in the disruption of diverse physiological functions.     

Experimental high-volume hemofiltration with predilutional tris-hydroxymethylaminomethane for correction of low tidal volume ventilation-induced acidosis

The most common method of controlling acidemia during lung‐protective ventilation is CO₂ removal with an extracorporeal lung assist (ECLA) system. Another possibility to prevent acidemia is based on intravenous (i.v.) application of tris‐hydroxymethyl‐aminomethane (3 mol/L, THAM) buffer, which can bind hydrogen protons and which can be removed from the body via renal replacement therapy (RRT). We investigated whether RRT combined with predilutional (prefilter) THAM‐application provides an alternative to ECLA for a rescue situation. For this, anesthetized pigs, 40 kg of body weight, six animals per group, underwent 5 h of acidemia (pH 7.19–7.24) induced by acid infusion and permissive hypercapnia (low tidal volume ventilation, PaCO₂ 80–90 mm Hg). Isovolemic, high‐volume hemofiltration (HVHF) was operated with predilutional THAM‐infusion for treatment. To evaluate adverse effects of this approach, we set up further groups: HVHF with postdilutional (post‐filter) THAM‐application; i.v.‐THAM without HVHF; normal pH homeostasis with HVHF. Acid‐base parameters, hemodynamics, renal function, and lung morphology were investigated. HVHF with predilutional THAM‐infusion of 8 mmol/kg/h allowed fast pH normalization, significant reduction in PaCO₂ to 56 mm Hg and tolerable hemodynamics. HVHF alone or lower dose i.v. THAM (2 mmol/kg/h) failed to produce a comparable result. A postdilutional THAM infusion reduced hemodynamic tolerability and increased lung edema formation. HVHF in pigs with normal acid‐base status resulted in a decreased base excess and urine acidification. In conclusion, predilutional THAM‐application and HVHF corrected the acid‐base disorder and improved pulmonary hemodynamics. Further studies are necessary to optimize the protocol including the dosage.     

Direct assessment of adherence and drug interactions in patients with hypertensive crisis—A cross‐sectional study in the Emergency Department

Though drug adherence is supposed to be low in hypertensive crisis (HTN‐C), there are no data available from direct adherence assessments. The aim of the present study was to evaluate adherence to prescribed antihypertensives and potential interactions of concomitant drugs and foods with prescribed antihypertensives in patients with HTN‐C by a direct evaluation via biochemical urine analysis. In the present cross‐sectional study, 100 patients with HTN‐C, admitted to the emergency department (ED), were included. A biochemical urine analysis using gas chromatography‐tandem mass spectrometry was performed. Out of 100 patients, 86 received antihypertensives. Urine analyses could be evaluated unambiguously in 62 patients. In 15 of these 62 patients (24%), a nonadherence could be demonstrated, and in 21 patients (34%), a partial nonadherence could be demonstrated. Patients with nonadherence or partial nonadherence showed a longer hypertension history (15[5‐22] vs 10[3‐15] years, P = 0.04) were prescribed more general medication (number 7.1 ± 3.4 vs 3.4 ± 1.8; P < 0.01) as well as antihypertensive drugs (number 2.8 ± 1.1 vs 1.5 ± 0.7, P < 0.01). A potential BP‐raising trigger by medications or food interaction was frequently detectable, predominantly with nonsteroidal anti‐inflammatory drugs (NSAIDs; n = 38), glucocorticoids (n = 8), antidepressants (n = 10), and licorice (n = 10). Nonadherence and partial nonadherence to prescribed antihypertensives might play a crucial role for the occurrence of HTN‐C. However, further case‐controlled studies are needed to confirm the present findings. Ingestion of concurrent over‐the‐counter drugs such as NSAIDs but also prescribed drugs as well as aliments may lead to critical BP elevation. In order to prevent HTN‐C, the present findings emphasize the importance for clinicians to pay attention to the issue of adherence and co‐medication.     

The wandering mind of men: ERP evidence for gender differences in attention bias towards attractive opposite sex faces

To examine the time course and automaticity of our attention bias towards attractive opposite sex faces, event-related potentials (ERPs) were recorded from 20 males and 20 females while they carried out a covert orienting task. Faces that were high, low or average in attractiveness, were presented in focus of attention, but were unrelated to task goals. Across the entire sample larger P2 amplitudes were found in response to both attractive and unattractive opposite sex faces, presumably reflecting early implicit selective attention to distinctive faces. In male but not female participants this was followed by an increased late slow wave for the attractive faces, signifying heightened processing linked to motivated attention. This latter finding is consistent with sexual strategy theory, which suggests that men and women have evolved to pursue different mating strategies with men being more attentive to cues such as facial beauty. In general, our ERP results suggest that, in addition to threat-related stimuli, other evolutionary-relevant information is also prioritized by our attention systems.