Vestibular contribution to spatial encoding.

Determining the spatial relation between objects and our location in the surroundings is essential for survival. Vestibular inputs provide key information about the position and movement of our head in the three-dimensional space, contributing to spatial navigation. Yet, their role in encoding spatial localisation of environmental targets remains to be fully understood. We probed the accuracy and precision of healthy participants' representations of environmental space by measuring their ability to encode the spatial location of visual targets (Experiment 1). Participants were asked to detect a visual light and then walk towards it. Vestibular signalling was artificially disrupted using stochastic galvanic vestibular stimulation (sGVS) applied selectively during encoding targets' location. sGVS impaired the accuracy and precision of locating the environmental visual targets. Importantly, this effect was specific to the visual modality. The location of acoustic targets was not influenced by vestibular alterations (Experiment 2). Our findings indicate that the vestibular system plays a role in localising visual targets in the surrounding environment, suggesting a crucial functional interaction between vestibular and visual signals for the encoding of the spatial relationship between our body position and the surrounding objects.

How path integration abilities of blind people change in different exploration conditions.

For animals to locate resources and stay safe, navigation is an essential cognitive skill. Blind people use different navigational strategies to encode the environment. Path integration significantly influences spatial navigation, which is the ongoing update of position and orientation during self-motion. This study examines two separate things: (i) how guided and non-guided strategies affect blind individuals in encoding and mentally representing a trajectory and (ii) the sensory preferences for potential navigational aids through questionnaire-based research. This study first highlights the significant role that the absence of vision plays in understanding body centered and proprioceptive cues. Furthermore, it also underscores the urgent need to develop navigation-assistive technologies customized to meet the specific needs of users.

The Techniques of Blood Purification in the Treatment of Sepsis and Other Hyperinflammatory Conditions.

Even in the absence of strong indications deriving from clinical studies, the removal of mediators is increasingly used in septic shock and in other clinical conditions characterized by a hyperinflammatory response. Despite the different underlying mechanisms of action, they are collectively indicated as blood purification techniques. Their main categories include blood- and plasma processing procedures, which can run in a stand-alone mode or, more commonly, in association with a renal replacement treatment. The different techniques and principles of function, the clinical evidence derived from multiple clinical investigations, and the possible side effects are reviewed and discussed along with the persisting uncertainties about their precise role in the therapeutic armamentarium of these syndromes.

The Role of the Intravenous IgA and IgM-Enriched Immunoglobulin Preparation in the Treatment of Sepsis and Septic Shock.

Polyclonal Intravenous Immunoglobulins (IvIg) are often administered to critically ill patients more as an act of faith than on the basis of relevant clinical studies. This particularly applies to the treatment of sepsis and septic shock because the current guidelines recommend against their use despite many investigations that have demonstrated their beneficial effects in different subsets of patients. The biology, mechanisms of action, and clinical experience related to the administration of IvIg are reviewed, which aim to give a more in-depth understanding of their properties in order to clarify their possible indications in sepsis and septic shock patients.

Spatial Sensory References for Vestibular Self-Motion Perception.

While navigating through the surroundings, we constantly rely on inertial vestibular signals for self-motion along with visual and acoustic spatial references from the environment. However, the interaction between inertial cues and environmental spatial references is not yet fully understood. Here we investigated whether vestibular self-motion sensitivity is influenced by sensory spatial references. Healthy participants were administered a Vestibular Self-Motion Detection Task in which they were asked to detect vestibular self-motion sensations induced by low-intensity Galvanic Vestibular Stimulation. Participants performed this detection task with or without an external visual or acoustic spatial reference placed directly in front of them. We computed the d prime ( d ' ) as a measure of participants' vestibular sensitivity and the criterion as an index of their response bias. Results showed that the visual spatial reference increased sensitivity to detect vestibular self-motion. Conversely, the acoustic spatial reference did not influence self-motion sensitivity. Both visual and auditory spatial references did not cause changes in response bias. Environmental visual spatial references provide relevant information to enhance our ability to perceive inertial self-motion cues, suggesting a specific interaction between visual and vestibular systems in self-motion perception.

Waterhouse-Friderichsen syndrome following a dog bite in an asplenic patient: case report and review of the literature.

The Waterhouse-Friderichsen syndrome represents a critical condition characterized by a septic shock associated with a disseminated intravascular coagulation causing the plugging of the microvascular network virtually all organs and systems, including the skin, the kidneys, the liver, and adrenal glands; the mortality rate is elevated, and survivors often must undergo multiple limb amputations. Here, we describe the uncommon case of an asplenic patient who developed this syndrome after a superficial wound caused by a dog bite causing an initial infection due to Capnocytophaga canimorsus that is part of the normal oral microbiome of pets. The clinical and pathological findings and the current and future therapeutic options are reviewed and discussed.

Interindividual differences influence multisensory processing during spatial navigation.

When moving through space, we encode multiple sensory cues that guide our orientation through the environment. The integration between visual and self-motion cues is known to improve navigation. However, spatial navigation may also benefit from multisensory external signals. The present study aimed to investigate whether humans combine auditory and visual landmarks with improving their navigation abilities. Two experiments with different cue reliability were conducted. In both, participants' task was to return an object to its original location by using landmarks, which could be visual-only, auditory-only, or audiovisual. We took error and variability of object relocation distance as measures of accuracy and precision. To quantify interference between cues and assess their weights, we ran a conflict condition with a spatial discrepancy between visual and auditory landmarks. Results showed comparable accuracy and precision when navigating with visual-only and audiovisual landmarks but greater error and variability with auditory-only landmarks. Splitting participants into two groups based on given unimodal weights revealed that only subjects who associated similar weights to auditory and visual cues showed precision benefit in audiovisual conditions. These findings suggest that multisensory integration occurs depending on idiosyncratic cue weighting. Future multisensory procedures to aid mobility must consider individual differences in encoding landmarks. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

How much I moved: Robust biases in self-rotation perception.

Vestibular cues are crucial to sense the linear and angular acceleration of our head in three-dimensional space. Previous literature showed that vestibular information precociously combines with other sensory modalities, such as proprioceptive and visual, to facilitate spatial navigation. Recent studies suggest that auditory cues may improve self-motion perception as well. The present study investigated the ability to estimate passive rotational displacements with and without virtual acoustic landmarks to determine how vestibular and auditory information interact in processing self-motion information. We performed two experiments. In both, healthy participants sat on a Rotational-Translational Chair. They experienced yaw rotations along the earth-vertical axis and performed a self-motion discrimination task. Their goal was to estimate both clockwise and counterclockwise rotations' amplitude, with no visual information available, reporting whether they felt to be rotated more or less than 45°. According to the condition, vestibular-only or audio-vestibular information was present. Between the two experiments, we manipulated the procedure of presentation of the auditory cues (passive vs. active production of sounds). We computed the point of subjective equality (PSE) as a measure of accuracy and the just noticeable difference (JND) as the precision of the estimations for each condition and direction of rotations. Results in both experiments show a strong overestimation bias of the rotations, regardless of the condition, the direction, and the sound generation conditions. Similar to previously found heading biases, this bias in rotation estimation may facilitate the perception of substantial deviations from the most relevant directions in daily navigation activities.

Immersive virtual reality interferes with default head-trunk coordination strategies in young children.

The acquisition of postural control is an elaborate process, which relies on the balanced integration of multisensory inputs. Current models suggest that young children rely on an 'en-block' control of their upper body before sequentially acquiring a segmental control around the age of 7, and that they resort to the former strategy under challenging conditions. While recent works suggest that a virtual sensory environment alters visuomotor integration in healthy adults, little is known about the effects on younger individuals. Here we show that this default coordination pattern is disrupted by an immersive virtual reality framework where a steering role is assigned to the trunk, which causes 6- to 8-year-olds to employ an ill-adapted segmental strategy. These results provide an alternate trajectory of motor development and emphasize the immaturity of postural control at these ages.

Kinetics of Immunoglobulins in Septic Shock Patients Treated With an IgM- and IgA-Enriched Intravenous Preparation: An Observational Study.

Objective: To assess the variations of the blood levels of immunoglobulins (Ig) in septic shock patients treated with an Ig preparation enriched in IgM and IgA (eIg). Design: The blood levels of Ig in survivors (S) and non-survivors (NS) of a group of septic shock patients were measured before the initial administration (D0) and 1 (D1), 4 (D4), and 7 (D7) days thereafter. The SAPS II score, the capillary permeability, the primary site of infection, the antibiotic appropriateness, and the outcome at 28 days were also assessed. Results: In the interval D0-D7, the IgM increased significantly only in the S while remained stable in NS; the IgA significantly increased in both groups; the IgG did not vary significantly in both groups. At D4, the capillary permeability significantly decreased in S but not in NS. Conclusions: The kinetics of the different classes of Ig after eIg were different between S and NS. This could be related either to (a) different capillary permeability in the two groups or to (b) higher Ig consumption in NS. Further studies to confirm the benefits of eIg in the treatment of sepsis syndrome and to define the specific target population and the correct eIg dose are warranted.

Prognostic significance of the interaction between abnormal umbilical and middle cerebral artery Doppler velocimetry in pregnancies complicated by fetal growth restriction.

OBJECTIVE: To evaluate the prognostic significance of the interaction between umbilical artery (UA) and middle cerebral artery (MCA) Doppler measurements in pregnancies complicated by fetal growth restriction (FGR). DESIGN: Cohort study. SETTING: Third-level Perinatology Center in Northern Italy. POPULATION: A study of 184 singleton pregnancies at 24-35 weeks' gestational age complicated by FGR and abnormal UA Doppler measurements. METHODS: FGR was diagnosed by serial ultrasonograms. Neonatal brain damage was defined as the presence of cystic leukomalacia or grade III-IV intraventricular hemorrhage. MAIN OUTCOME MEASURES: Perinatal death and neonatal brain damage. RESULTS: The prevalence of fetal/neonatal death or brain damage was 18.2% (16/88) in pregnancies with UA absent/reversed diastolic flow and 4.2% (4/96) in those with increased UA Doppler pulsatility. Stepwise logistic regression identified decreasing gestational age (OR=1.75, 95% confidence interval, CI=1.35-2.22) and absent/reversed UA blood flow (OR=3.34, 95% CI=1.1-10.9) as predictors of fetal/neonatal death or brain damage. A MCA pulsatility index below the 10th percentile was a risk factor for fetal/neonatal death or brain damage among women with absent/reversed UA diastolic flow (14/53 as compared to 2/35; OR=5.9, CI =1.4-40.3) but not in pregnancies with forward velocity (1/33 as compared to 3/63; OR=0.63, 95% CI=0.02-6.13, Synergy index=27.7, p=0.007). CONCLUSIONS: In pregnancies complicated by FGR and absent/reversed UA end diastolic flow, vasodilatation of the MCA is a risk factor for neonatal death or brain damage.

Preeclampsia and brain damage among preterm infants: a changed panorama in a 20-year analysis.

The purpose of this study was to compare the rates of preterm infant brain damage between preeclamptic and normotensive pregnancies during a 20-year period. A cohort study was performed of 1201 singleton pregnancies between 24 and 35 weeks gestation delivered at a single institution during the period 1984-2003. Preeclampsia was diagnosed according to standard criteria. Periventricular/intraventricular hemorrhage (PV-IVH) and periventricular leukomalacia were diagnosed by postnatal cranial ultrasound. Severe infant brain damage was defined as the presence of cystic periventricular leukomalacia and/or intraparenchymal hemorrhage or IVH with ventricular dilation. Logistic regression analysis was used to compute the rates of neonatal brain damage adjusting for potential confounders and to perform an interaction study. The crude rates of severe brain damage among the 329 preeclamptic pregnancies were 11.6% (five of 43) in the period 1984 to 1988 and 0.86% (one of 116) in the period 1999 to 2003 ( P for trend < 0.001). The adjusted decrement in the rate of severe brain damage per 5-year period was 65.7% (95% confidence interval [CI], 35.1 to 81.9). The crude rates of severe brain damage among the 872 normotensive pregnancies were 6.1% (eight of 132) in the period 1984 to 1988 and 3.4% (10 of 298) in the period 1999 to 2003 ( P for trend = 0.03). The adjusted decrement per 5-year period was 21.7 (95% CI, 10.6 to 31.4; P = 0.001 compared with infants born to mothers with preeclampsia). Multivariable analysis of interaction confirmed that, during the period of the study, the decrement in the rates of PV-IVH ( P for interaction = 0.04) and of severe brain damage ( P for interaction = 0.03) was higher among preeclamptic than normotensive pregnancies. At our institution, in the last two decades the decrement in the rates of PV-IVH and severe brain damage among preterm infants was significantly higher in preeclamptic than normotensive pregnancies.