Ventricular enlargement after moderate or severe head injury: a frequent and neglected problem

Subarachnoid Hemorrhage Depletes Calcitonin Gene-Related Peptide Levels of Trigeminal Neurons in Rat Dura Mater

Subarachnoid hemorrhage (SAH) remains a major cause of cerebrovascular morbidity, eliciting severe headaches and vasospasms that have been shown to inversely correlate with vasodilator calcitonin gene-related peptide (CGRP) levels. Although dura mater trigeminal afferents are an important source of intracranial CGRP, little is known about the effects of SAH on these neurons in preclinical models. The present study evaluated changes in CGRP levels and expression in trigeminal primary afferents innervating the dura mater 72 h after experimentally induced SAH in adult rats. SAH, eliciting marked damage revealed by neurological examination, significantly reduced the density of CGRP-immunoreactive nerve fibers both in the dura mater and the trigeminal caudal nucleus in the medulla but did not affect the total dural nerve fiber density. SAH attenuated ex vivo dural CGRP release by ~40% and in the trigeminal ganglion, reduced both CGRP mRNA levels and the number of highly CGRP-immunoreactive cell bodies. In summary, we provide novel complementary evidence that SAH negatively affects the integrity of the CGRP-expressing rat trigeminal neurons. Reduced CGRP levels suggest likely impaired meningeal neurovascular functions contributing to SAH complications. Further studies are to be performed to reveal the importance of impaired CGRP synthesis and its consequences in central sensory processing.

Structural neuroimaging markers of normal pressure hydrocephalus versus Alzheimer's dementia and Parkinson's disease, and hydrocephalus versus atrophy in chronic TBI-a narrative review

Introduction

Normal Pressure Hydrocephalus (NPH) is a prominent type of reversible dementia that may be treated with shunt surgery, and it is crucial to differentiate it from irreversible degeneration caused by its symptomatic mimics like Alzheimer's Dementia (AD) and Parkinson's Disease (PD). Similarly, it is important to distinguish between (normal pressure) hydrocephalus and irreversible atrophy/degeneration which are among the chronic effects of Traumatic Brain Injury (cTBI), as the former may be reversed through shunt placement. The purpose of this review is to elucidate the structural imaging markers which may be foundational to the development of accurate, noninvasive, and accessible solutions to this problem.

Methods

By searching the PubMed database for keywords related to NPH, AD, PD, and cTBI, we reviewed studies that examined the (1) distinct neuroanatomical markers of degeneration in NPH versus AD and PD, and atrophy versus hydrocephalus in cTBI and (2) computational methods for their (semi-) automatic assessment on Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) scans.

Results

Structural markers of NPH and those that can distinguish it from AD have been well studied, but only a few studies have explored its structural distinction between PD. The structural implications of cTBI over time have been studied. But neuroanatomical markers that can predict shunt response in patients with either symptomatic idiopathic NPH or post-traumatic hydrocephalus have not been reliably established. MRI-based markers dominate this field of investigation as compared to CT, which is also reflected in the disproportionate number of MRI-based computational methods for their automatic assessment.

Conclusion

Along with an up-to-date literature review on the structural neurodegeneration due to NPH versus AD/PD, and hydrocephalus versus atrophy in cTBI, this article sheds light on the potential of structural imaging markers as (differential) diagnostic aids for the timely recognition of patients with reversible (normal pressure) hydrocephalus, and opportunities to develop computational tools for their objective assessment.

Evolution of Severe Closed Head Injury: Assessing Ventricular Volume and Behavioral Measures at 30 and 90 Days Post-Injury

Background: Assessing functional outcomes in Severe Closed Head Injury (SCHI) is complex due to brain parenchymal changes. This study examines the Ventricles to Intracranial Volume Ratio (VBR) as a metric for these changes and its correlation with behavioral scales. Methods: Thirty-one SCHI patients were included. VBR was derived from CT scans at 3, 30, and 90 days post-injury and compared with Levels of Cognitive Functioning (LCF), Disability Rating Scale (DRS), and Early Rehabilitation Barthel Index (ERBI) assessments at 30 and 90 days. Results: Ten patients were excluded post-decompressive craniectomy or ventriculoperitoneal shunt. Findings indicated a VBR decrease at 3 days, suggesting acute phase compression, followed by an increase from 30 to 90 days, indicative of post-acute brain atrophy. VBR correlated positively with the Marshall score in the initial 72 h, positioning it as an early indicator of subsequent brain atrophy. Nevertheless, in contrast to the Marshall score, VBR had stronger associations with DRS and ERBI at 90 days. Conclusions: VBR, alongside behavioral assessments, presents a robust framework for evaluating SCHI progression. It supports early functional outcome correlations informing therapeutic approaches. VBR's reliability underscores its utility in neurorehabilitation for ongoing SCHI assessment and aiding clinical decisions.

Longitudinal Changes in Regional Brain Volumes and Cognition of Professional Fighters With Traumatic Encephalopathy Syndrome

BACKGROUND AND OBJECTIVES

Due to current limitations in diagnosing chronic traumatic encephalopathy (CTE) clinically, traumatic encephalopathy syndrome (TES) has been proposed as the clinical presentation of suspected CTE. This study aimed to determine whether there was an association between a clinical diagnosis of TES and subsequent temporal decline in cognitive or MRI volumetric measures.

METHODS

This was a secondary analysis of the Professional Athletes Brain Health Study (PABHS), inclusive of active and retired professional fighters older than 34 years. All athletes were adjudicated as TES positive (TES+) or TES negative (TES-) based on the 2021 clinical criteria. General linear mixed models were used to compare MRI regional brain volumes and cognitive performance between groups.

RESULTS

A total of 130 fighters met inclusion criteria for consensus conference. Of them, 52 fighters (40%) were adjudicated as TES+. Athletes with a TES+ diagnosis were older and had significantly lower education. Statistically significant interactions and between-group total mean differences were found in all MRI volumetric measurements among the TES+ group compared with those among the TES- group. The rate of volumetric change indicated a significantly greater increase for lateral (estimate = 5,196.65; 95% CI = 2642.65, 7750.66) and inferior lateral ventricles (estimate = 354.28; 95% CI = 159.90, 548.66) and a decrease for the hippocampus (estimate = -385.04, 95% CI = -580.47, -189.62), subcortical gray matter (estimate = -4,641.08; 95% CI = -6783.98, -2498.18), total gray matter (estimate = -26492.00; 95% CI = -50402.00, -2582.32), and posterior corpus callosum (estimate = -147.98; 95% CI = -222.33, -73.62). Likewise, the rate of cognitive decline was significantly greater for reaction time (estimate = 56.31; 95% CI = 26.17, 86.45) and other standardized cognitive scores in the TES+ group.

DISCUSSION

The 2021 TES criteria clearly distinguishes group differences in the longitudinal presentation of volumetric loss in select brain regions and cognitive decline among professional fighters 35 years and older. This study suggests that a TES diagnosis may be useful in professional sports beyond football, such as boxing and mixed martial arts. These findings further suggest that the application of TES criteria may be valuable clinically in predicting cognitive decline.

Intracranial compliance and volumetry in patients with traumatic brain injury

BACKGROUND

Cerebral edema (CE) and intracranial hypertension (IHT) are complications of numerous neurological pathologies. However, the study of CE and noninvasive methods to predict IHT remains rudimentary. This study aims to identify in traumatic brain injury (TBI) patients the relationship between the volume of the lateral ventricles and the parameters of the noninvasive intracranial pressure waveform (nICPW).

METHODS

This is an analytical, descriptive, and cross-sectional study with nonsurgical TBI patients. The monitoring of nICPW was performed with a mechanical strain gauge, and the volumetry of the lateral ventricles was calculated using the free 3D Slicer software, both during the acute phase of the injury. The linear model of fixed and random mixed effects with Gamma was used to calculate the influence of nICPW parameters (P2/P1 and time-to-peak [TTP]) values on volumetry.

RESULTS

Considering only the fixed effects of the sample, there was P = 0.727 (95% CI [-0.653; 0.364]) for the relationship between P2/P1 and volumetry and 0.727 (95% CI [-1.657; 1.305]) for TTP and volumetry. Considering the fixed and random effects, there was P = 8.5e-10 (95% CI [-0.759; 0.355]) for the relationship between P2/P1 and volumetry and 8.5e-10 (95% CI [-2.001; 0.274]) for TTP and volumetry.

CONCLUSION

The present study with TBI patients found association between nICPW parameters and the volume of the lateral ventricles in the 1st days after injury.

Multimodal Neuromonitoring and Neurocritical Care in Swine to Enhance Translational Relevance in Brain Trauma Research

Neurocritical care significantly impacts outcomes after moderate-to-severe acquired brain injury, but it is rarely applied in preclinical studies. We created a comprehensive neurointensive care unit (neuroICU) for use in swine to account for the influence of neurocritical care, collect clinically relevant monitoring data, and create a paradigm that is capable of validating therapeutics/diagnostics in the unique neurocritical care space. Our multidisciplinary team of neuroscientists, neurointensivists, and veterinarians adapted/optimized the clinical neuroICU (e.g., multimodal neuromonitoring) and critical care pathways (e.g., managing cerebral perfusion pressure with sedation, ventilation, and hypertonic saline) for use in swine. Moreover, this neurocritical care paradigm enabled the first demonstration of an extended preclinical study period for moderate-to-severe traumatic brain injury with coma beyond 8 h. There are many similarities with humans that make swine an ideal model species for brain injury studies, including a large brain mass, gyrencephalic cortex, high white matter volume, and topography of basal cisterns, amongst other critical factors. Here we describe the neurocritical care techniques we developed and the medical management of swine following subarachnoid hemorrhage and traumatic brain injury with coma. Incorporating neurocritical care in swine studies will reduce the translational gap for therapeutics and diagnostics specifically tailored for moderate-to-severe acquired brain injury.

Volumetric MRI Findings in Mild Traumatic Brain Injury (mTBI) and Neuropsychological Outcome

Region of interest (ROI) volumetric assessment has become a standard technique in quantitative neuroimaging. ROI volume is thought to represent a coarse proxy for making inferences about the structural integrity of a brain region when compared to normative values representative of a healthy sample, adjusted for age and various demographic factors. This review focuses on structural volumetric analyses that have been performed in the study of neuropathological effects from mild traumatic brain injury (mTBI) in relation to neuropsychological outcome. From a ROI perspective, the probable candidate structures that are most likely affected in mTBI represent the target regions covered in this review. These include the corpus callosum, cingulate, thalamus, pituitary-hypothalamic area, basal ganglia, amygdala, and hippocampus and associated structures including the fornix and mammillary bodies, as well as whole brain and cerebral cortex along with the cerebellum. Ventricular volumetrics are also reviewed as an indirect assessment of parenchymal change in response to injury. This review demonstrates the potential role and limitations of examining structural changes in the ROIs mentioned above in relation to neuropsychological outcome. There is also discussion and review of the role that post-traumatic stress disorder (PTSD) may play in structural outcome in mTBI. As emphasized in the conclusions, structural volumetric findings in mTBI are likely just a single facet of what should be a multimodality approach to image analysis in mTBI, with an emphasis on how the injury damages or disrupts neural network integrity. The review provides an historical context to quantitative neuroimaging in neuropsychology along with commentary about future directions for volumetric neuroimaging research in mTBI.

Association of sub-acute changes in plasma amino acid levels with long-term brain pathologies in a rat model of moderate-severe traumatic brain injury

Introduction

Traumatic brain injury (TBI) induces a cascade of cellular alterations that are responsible for evolving secondary brain injuries. Changes in brain structure and function after TBI may occur in concert with dysbiosis and altered amino acid fermentation in the gut. Therefore, we hypothesized that subacute plasma amino acid levels could predict long-term microstructural outcomes as quantified using neurite orientation dispersion and density imaging (NODDI).

Methods

Fourteen 8-10-week-old male rats were randomly assigned either to sham (n = 6) or a single moderate-severe TBI (n = 8) procedure targeting the primary somatosensory cortex. Venous blood samples were collected at days one, three, seven, and 60 post-procedure and NODDI imaging were carried out at day 60. Principal Component Regression analysis was used to identify time dependent plasma amino acid concentrations after in the subacute phase post-injury that predicted NODDI metric outcomes at day 60.

Results

The TBI group had significantly increased plasma levels of glutamine, arginine, alanine, proline, tyrosine, valine, isoleucine, leucine, and phenylalanine at days three-seven post-injury. Higher levels of several neuroprotective amino acids, especially the branched-chain amino acids (valine, isoleucine, leucine) and phenylalanine, as well as serine, arginine, and asparagine at days three-seven post-injury were also associated with lower isotropic diffusion volume fraction measures in the ventricles and thus lesser ventricular dilation at day 60.

Discussion

In the first such study, we examined the relationship between the long-term post-TBI microstructural outcomes across whole brain and the subacute changes in plasma amino acid concentrations. At days three to seven post-injury, we observed that increased plasma levels of several amino acids, particularly the branched-chain amino acids and phenylalanine, were associated with lesser degrees of ventriculomegaly and hydrocephalus TBI neuropathology at day 60 post-injury. The results imply that altered amino acid fermentation in the gut may mediate neuroprotection in the aftermath of TBI.

A single closed head injury in male adult mice induces chronic, progressive white matter atrophy and increased phospho-tau expressing oligodendrocytes

Traumatic brain injury (TBI) acutely damages the brain; this injury can evolve into chronic neurodegeneration. While much is known about the chronic effects arising from multiple mild TBIs, far less is known about the long-term effects of a single moderate to severe TBI. We found that a single moderate closed head injury to mice induces diffuse axonal injury within 1-day post-injury (DPI). At 14 DPI, injured animals have atrophy of ipsilesional cortex, thalamus, and corpus callosum, with bilateral atrophy of the dorsal fornix. Atrophy of the ipsilesional corpus callosum is accompanied by decreased fractional anisotropy and increased mean and radial diffusivity that remains unchanged between 14 and 180 DPI. Injured animals show an increased density of phospho-tau immunoreactive (pTau+) cells in the ipsilesional cortex and thalamus, and bilaterally in corpus callosum. Between 14 and 180 DPI, atrophy occurs in the ipsilesional ventral fornix, contralesional corpus callosum, and bilateral internal capsule. Diffusion tensor MRI parameters remain unchanged in white matter regions with delayed atrophy. Between 14 and 180 DPI, pTau+ cell density increases bilaterally in corpus callosum, but decreases in cortex and thalamus. The location of pTau+ cells within the ipsilesional corpus callosum changes between 14 and 180 DPI; density of all cells increases including pTau+ or pTau- cells. >90% of the pTau+ cells are in the oligodendrocyte lineage in both gray and white matter. Density of thioflavin-S+ cells in thalamus increases by 180 DPI. These data suggest a single closed head impact produces multiple forms of chronic neurodegeneration. Gray and white matter regions proximal to the impact site undergo early atrophy. More distal white matter regions undergo chronic, progressive white matter atrophy with an increasing density of oligodendrocytes containing pTau. These data suggest a complex chronic neurodegenerative process arising from a single moderate closed head injury.

Temporal Horn Enlargements Predict Secondary Hydrocephalus Diagnosis Earlier than Evans' Index

The aim of this study was to identify early radiological signs of secondary hydrocephalus. We retrieved neuroradiological data from scans performed at various times in patients who underwent surgery for secondary hydrocephalus due to severe traumatic brain injury (TBI), subarachnoid haemorrhage (SAH), or brain tumour (BT). Baseline measurements, performed on the earliest images acquired after the neurological event (T0), included Evans’ index, the distance between frontal horns, and the widths of both temporal horns. The next neuroimage that showed an increase in at least one of these four parameters—and that lead the surgeon to act—was selected as an indication of ventricular enlargement (T1). Comparisons of T0 and T1 neuroimages showed increases in Evans’ index, in the mean frontal horn distance, and in the mean right and left temporal horn widths. Interestingly, in T1 scans, mean Evans’ index scores > 0.30 were only observed in patients with BT. However, the temporal horn widths increased up to ten-fold in most patients, independent of Evans’ index scores. In conclusion temporal horn enlargements were the earliest, most sensitive findings in predicting ventricular enlargement secondary to TBI, SAH, or BT. To anticipate a secondary hydrocephalus radiological diagnosis, clinicians should measure both Evans’ index and the temporal horn widths, to avoid severe disability and poor outcome related to temporal lobe damage.

Subacute cytokine changes after a traumatic brain injury predict chronic brain microstructural alterations on advanced diffusion imaging in the male rat

INTRODUCTION

The process of neuroinflammation occurring after traumatic brain injury (TBI) has received significant attention as a potential prognostic indicator and interventional target to improve patients' outcomes. Indeed, many of the secondary consequences of TBI have been attributed to neuroinflammation and peripheral inflammatory changes. However, inflammatory biomarkers in blood have not yet emerged as a clinical tool for diagnosis of TBI and predicting outcome. The controlled cortical impact model of TBI in the rodent gives reliable readouts of the dynamics of post-TBI neuroinflammation. We now extend this model to include a panel of plasma cytokine biomarkers measured at different time points post-injury, to test the hypothesis that these markers can predict brain microstructural outcome as quantified by advanced diffusion-weighted magnetic resonance imaging (MRI).

METHODS

Fourteen 8-10-week-old male rats were randomly assigned to sham surgery (n = 6) and TBI (n = 8) treatment with a single moderate-severe controlled cortical impact. We collected blood samples for cytokine analysis at days 1, 3, 7, and 60 post-surgery, and carried out standard structural and advanced diffusion-weighted MRI at day 60. We then utilized principal component regression to build an equation predicting different aspects of microstructural changes from the plasma inflammatory marker concentrations measured at different time points.

RESULTS

The TBI group had elevated plasma levels of IL-1β and several neuroprotective cytokines and chemokines (IL-7, CCL3, and GM-CSF) compared to the sham group from days 3 to 60 post-injury. The plasma marker panels obtained at day 7 were significantly associated with the outcome at day 60 of the trans-hemispheric cortical map transfer process that is a frequent finding in unilateral TBI models.

DISCUSSION

These results confirm and extend prior studies showing that day 7 post-injury is a critical temporal window for the reorganisation process following TBI. High plasma level of IL-1β and low plasma levels of the neuroprotective IL-7, CCL3, and GM-CSF of TBI animals at day 60 were associated with greater TBI pathology.

Traumatic brain injury augurs ill for prolonged deficits in the brain's structural and functional integrity following controlled cortical impact injury

Previous neuroimaging studies in rodents investigated effects of the controlled cortical impact (CCI) model of traumatic brain injury (TBI) within one-month post-TBI. This study extends this temporal window to monitor the structural–functional alterations from two hours to six months post-injury. Thirty-seven male Sprague–Dawley rats were randomly assigned to TBI and sham groups, which were scanned at two hours, 1, 3, 7, 14, 30, 60 days, and six months following CCI or sham surgery. Structural MRI, diffusion tensor imaging, and resting-state functional magnetic resonance imaging were acquired to assess the dynamic structural, microstructural, and functional connectivity alterations post-TBI. There was a progressive increase in lesion size associated with brain volume loss post-TBI. Furthermore, we observed reduced fractional anisotropy within 24 h and persisted to six months post-TBI, associated with acutely reduced axial diffusivity, and chronic increases in radial diffusivity post-TBI. Moreover, a time-dependent pattern of altered functional connectivity evolved over the six months’ follow-up post-TBI. This study extends the current understanding of the CCI model by confirming the long-term persistence of the altered microstructure and functional connectivity, which may hold a strong translational potential for understanding the long-term sequelae of TBI in humans.

Hydrocephalus and Cerebrospinal Fluid Analysis Following Severe Traumatic Brain Injury: Evaluation of a Prospective Cohort

The development of hydrocephalus after severe traumatic brain injury (TBI) is an under-recognized healthcare phenomenon and can increase morbidity. The current study aims to characterize post-traumatic hydrocephalus (PTH) in a large cohort. Patients were prospectively enrolled age 16-80 years old with Glasgow Coma Scale (GCS) score ≤8. Demographics, GCS, Injury Severity Score (ISS), surgery, and cerebrospinal fluid (CSF) were analyzed. Outcomes were shunt failure and Glasgow Outcome Scale (GOS) at 6 and 12-months. Statistical significance was assessed at p < 0.05. In 402 patients, mean age was 38.0 ± 16.7 years and 315 (78.4%) were male. Forty (10.0%) patients developed PTH, with predominant injuries being subdural hemorrhage (36.4%) and diffuse axonal injury (36.4%). Decompressive hemicraniectomy (DHC) was associated with hydrocephalus (OR 3.62, 95% CI (1.62-8.07), p < 0.01). Eighteen (4.5%) patients had shunt failure and proximal obstruction was most common. Differences in baseline CSF cell count were associated with increased shunt failure. PTH was not associated with worse outcomes at 6 (p = 0.55) or 12 (p = 0.47) months. Hydrocephalus is a frequent sequela in 10.0% of patients, particularly after DHC. Shunt placement and revision procedures are common after severe TBI, within the first 4 months of injury and necessitates early recognition by the clinician.

Diverse changes in microglia morphology and axonal pathology during the course of 1 year after mild traumatic brain injury in pigs

Over 2.8 million people experience mild traumatic brain injury (TBI) in the United States each year, which may lead to long-term neurological dysfunction. The mechanical forces that are caused by TBI propagate through the brain to produce diffuse axonal injury (DAI) and trigger secondary neuroinflammatory cascades. The cascades may persist from acute to chronic time points after injury, altering the homeostasis of the brain. However, the relationship between the hallmark axonal pathology of diffuse TBI and potential changes in glial cell activation or morphology have not been established in a clinically relevant large animal model at chronic time points. In this study, we assessed the tissue from pigs subjected to rapid head rotation in the coronal plane to generate mild TBI. Neuropathological assessments for axonal pathology, microglial morphological changes, and astrocyte reactivity were conducted in specimens out to 1-year post-injury. We detected an increase in overall amyloid precursor protein pathology, as well as periventricular white matter and fimbria/fornix pathology after a single mild TBI. We did not detect the changes in corpus callosum integrity or astrocyte reactivity. However, detailed microglial skeletal analysis revealed changes in morphology, most notably increases in the number of microglial branches, junctions, and endpoints. These subtle changes were most evident in periventricular white matter and certain hippocampal subfields, and were observed out to 1-year post-injury in some cases. These ongoing morphological alterations suggest persistent change in neuroimmune homeostasis. Additional studies are needed to characterize the underlying molecular and neurophysiological alterations, as well as potential contributions to neurological deficits.

Post-traumatic hydrocephalus - incidence, risk factors, treatment, and clinical outcome

OBJECTIVES

Post-traumatic hydrocephalus (PTH) is well-known after traumatic brain injury (TBI), but there is limited evidence regarding patient selection for ventriculo-peritoneal (VP)-shunt treatment. In this study, we investigated the incidence and risk factors for PTH and the indication for and outcome after shunt treatment.

MATERIALS AND METHODS

In this retrospective study, 836 TBI patients, treated at our neurointensive care (NIC) unit at Uppsala university hospital, Sweden, between 2008 and 2018, were included. Demography, admission status, radiology, treatments, and outcome variables were evaluated.

RESULTS

Post-traumatic ventriculomegaly occurred in 46% of all patients at NIC discharge. Twenty-nine (3.5%) patients received a VP-shunt. Lower GCS M at admission, greater amount of subarachnoid hemorrhage, meningitis, decompressive craniectomy (DC), and ventriculomegaly at NIC discharge were risk factors for receiving a VP-shunt. Fourteen of the PTH patients showed impeded recovery or low-pressure hydrocephalus symptoms, of whom 13 experienced subjective clinical improvement after shunt treatment. Five PTH patients showed deterioration in consciousness, of whom four improved following shunt treatment. Five DC patients received a shunt due to subdural hygromas (n =2) or external brain herniation (n = 3), of whom two patients improved following treatment. Five patients were vegetative with concurrent ventriculomegaly and these patients did not have any positive shunt response. Altogether, 19 (66%) PTH patients improved after shunt surgery.

CONCLUSION

Post-traumatic ventriculomegaly was common, but few developed symptomatic PTH and received a VP-shunt. Patients with low-pressure hydrocephalus symptoms had the best shunt response, whereas patients with suspected vegetative state exhibited a minimal shunt response.

Incidence of post-traumatic hydrocephalus in traumatic brain injury patients that underwent DC versus those that were managed without DC: A systematic review and meta-analysis

Introduction

There is an ongoing debate whether Decompressive Craniectomy (DC) serves as an independent risk factor for the development of Post-traumatic Hydrocephalus (PTH).

Research question

The aim of this systematic review and meta-analysis was to compare the incidence of PTH in TBI patients that underwent DC versus those that were managed without DC.

Materials and methods

The literature was systematically reviewed to identify studies with specific inclusion criteria: (1) Randomized Controlled Trials and observational studies with more than 10 patients in each study arm, (2) comparing the incidence of PTH, (3) in patients aged ≥15 years old, (4) that either underwent DC or received other treatment (non-DC). (5) Only studies in English were included and (6) no restrictions were applied on publication date. The pooled Odds Ratio (OR) and Confidence Interval (CI) were calculated. The quality of the included studies was assessed using the ROBINS and RoB 2.0 tools.

Results

Evidence from six articles was synthesized, incorporating data from 2522 patients. A statistically significant higher occurrence of PTH [OR (95% CI): 4.84 (2.51, 9.31); Pz ​< ​0.00001] was identified in patients undergoing DC for TBI when compared to those that were managed without DC. The same was true when only patients with severe TBI were included in the analysis [OR (95% CI): 2.87 (1.85, 4.43); Pz ​< ​0.00001].

Discussion and conclusion

Our study has shown, within limitations, a clear association between DC and PTH. Further prospective studies, providing high-quality evidence, are needed to definitively establish any causative relationship between DC and PTH.

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TBIs are associated with the development of PTH.

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Patients undergoing decompressive craniectomy are more likely to develop PTH.

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Further studies should be conducted to establish a causative relationship.

Blast exposure predisposes the brain to increased neurological deficits in a model of blast plus blunt traumatic brain injury

Soldiers are often exposed to more than one traumatic brain injury (TBI) over the course of their service. In recent years, more attention has been drawn to the increased risk of neurological deficits caused by the 'blast plus' polytrauma, which typically is a blast trauma combined with other forms of TBI. In this study, we investigated the behavioral and neuronal deficits resulting from a blast plus injury involving a mild-moderate blast followed by a mild blunt trauma using the fluid percussion injury model. We identified that the blast injury predisposed the brain to increased cognitive deficits, chronic ventricular enlargement, increased neurodegeneration at acute time points and chronic neuronal loss. Interestingly, a single blast and single blunt injury differed in their onset and manifestation of cognitive and regional neuronal loss. We also identified the presence of cleaved RIP1 from caspase 8 mediated apoptosis in the blunt injury while the blast injury did not activate immediate apoptosis but led to decreased hilar neuronal survival over time.

Long-term Outcomes and Risk Factors Related to Hydrocephalus After Intracerebral Hemorrhage

Hydrocephalus after intracerebral hemorrhage (ICH) is a common and treatable complication. However, the long-term outcomes and factors for predicting hydrocephalus have seldom been studied. The goal of this study was to determine the long-term outcomes and analyze the risk factors of hydrocephalus after ICH. A consecutive series of 1342 patients with ICH were reviewed from 2010 to 2016 to identify significant risk factors for hydrocephalus. Patients with a first-ever ICH without any prior diagnosis of hydrocephalus after ICH were followed up for survival status and cause of death. Risk factors for hydrocephalus were evaluated by using logistic regression analysis. Out of a total of 1342 ICH patients, 120 patients (8.9%) had hydrocephalus. The risk factors for hydrocephalus (≤ 3 days) were infratentorial hemorrhage (p = 0.000), extension to ventricles (p = 0.000), greater ICH volume (p = 0.09), and hematoma expansion (p = 0.01). Extension to ventricles (p = 0.022) was the only independent risk factor for hydrocephalus (4-13 days), while extension to ventricles (p = 0.028), decompressive craniotomy (p = 0.032), and intracranial infection (p = 0.001) were independent predictors of hydrocephalus (≥ 14 days). Patients were followed up for a median of 5.2 years (IQR 3.3-7.3 years). Estimated all-cause mortality was significantly higher in the ICH patients with hydrocephalus than that without hydrocephalus (HR 3.22, 95% CI 2.42-4.28; p = 0.000). Fifty-nine (49.2%) died and 40 (33.3%) had a favorable outcome in patients with hydrocephalus. Of all deaths, 30.5% were from ICH and 64.4% from infection. Hydrocephalus is a frequent complication of ICH and most commonly occurs at the onset of ICH. Patients with hydrocephalus show relatively higher mortality. ClinicalTrials.gov Identifier: NCT02135783 (May 7, 2014).

Development of normal pressure hydrocephalus following post-traumatic external hydrocephalus in an adult patient

We report the case of 74-year-old patient suspected of post-traumatic external hydrocephalus (EH) following a mild traumatic brain injury with a progressive neurological decline and a concomitant enlargement of subarachnoid spaces without ventriculomegaly on CT scan. A lumbar puncture revealed raised ICP and a careful CSF withdrawal was performed, resulting in an immediate neurological improvement, confirming the diagnosis of EH. During the 20-month follow-up, the patient presented progressive signs of normal pressure hydrocephalus (NPH): gait and cognitive decline, ventriculomegaly and the lumbar infusion study confirmed disturbed CSF dynamics. The patient underwent a ventriculoperitoneal shunt surgery, resulting in a long-lasting improvement.

Examining the Progressive Behavior and Neuropathological Outcomes Associated with Chronic Repetitive Mild Traumatic Brain Injury in Rats

While the physical and behavioral symptomologies associated with a single mild traumatic brain injury (mTBI) are typically transient, repetitive mTBIs (RmTBI) have been associated with persisting neurological deficits. Therefore, this study examined the progressive changes in behavior and the neuropathological outcomes associated with chronic RmTBI through adolescence and adulthood in male and female Sprague Dawley rats. Rats experienced 2 mTBIs/week for 15 weeks and were periodically tested for changes in motor behavior, cognitive function, emotional disturbances, and aggression. Brain tissue was examined for neuropathological changes in ventricle size and presentation of Iba1 and GFAP. We did not see progressively worse behavioral impairments with the accumulation of injuries or time, but did find evidence for neurological and functional change (motor disturbance, reduced exploration, reduced aggression, alteration in depressive-like behavior, deficits in short-term working memory). Neuropathological assessment of RmTBI animals identified an increase in ventricle size, prolonged changes in GFAP, and sex differences in Iba1, in the corpus callosum, thalamus, and medial prefrontal cortex. Telomere length reduced exponentially as the injury load increased. Overall, chronic RmTBI did not result in accumulating behavioral impairment, and there is a need to further investigate progressive behavioral changes associated with repeated injuries in adolescence and young adulthood.

Factors associated with the development and outcome of hydrocephalus after decompressive craniectomy for traumatic brain injury

Posttraumatic hydrocephalus (PTH) is common in patients undergoing decompressive craniectomy (DC) for traumatic brain injury (TBI), but the incidence, mechanisms, and risk factors have not been fully elucidated. This study aimed to determine the incidence of and the factors associated with PTH. We retrospectively reviewed patients who underwent DC for TBI at our institute between January 2014 and December 2018. We identified and compared the demographic, clinical, and radiological data, and 12-month functional outcome (as assessed by the Glasgow Outcome Scale [GOS]) between patients who developed PTH and those who did not. Logistic regression analyses were performed to identify risk factors for PTH. Additionally, the influence of PTH on unfavorable functional outcome was analyzed. PTH developed in 18 (18.95%) of the 95 patients who survived at 1 month after DC. A multivariate analysis indicated that postoperative intraventricular hemorrhage (odds ratio [OR] 4.493, P = 0.020), postoperative subdural hygroma (OR 4.074, P = 0.021), and postoperative hypothermia treatment (OR 9.705, P = 0.010) were significantly associated with PTH. The 12-month functional outcome significantly differed between the patients who developed PTH and those who did not (P = 0.049). Patients who developed PTH had significantly poorer 12-month functional outcomes than those who did not (P = 0.049). Another multivariate analysis indicated that subdural hemorrhage (OR 6.814, P = 0.031) and the presence of at least one dilated pupil before DC (OR 8.202, P = 0.000) were significantly associated with unfavorable functional outcomes (GOS grades 1-3). Although the influence of PTH (OR 5.122, P = 0.056) was not statistically significant in the multivariate analysis, it had a great impact on unfavorable functional outcomes. PTH considerably affects functional outcomes at 12 months after DC for TBI. Furthermore, postoperative imaging findings such as intraventricular hemorrhage and subdural hygroma can predict the development of PTH; therefore, careful observation is required during the follow-up period.

(-)-Phenserine Ameliorates Contusion Volume, Neuroinflammation, and Behavioral Impairments Induced by Traumatic Brain Injury in Mice

Traumatic brain injury (TBI), a major cause of mortality and morbidity, affects 10 million people worldwide, with limited treatment options. We have previously shown that (-)-phenserine (Phen), an acetylcholinesterase inhibitor originally designed and tested in clinical phase III trials for Alzheimer's disease, can reduce neurodegeneration after TBI and reduce cognitive impairments induced by mild TBI. In this study, we used a mouse model of moderate to severe TBI by controlled cortical impact to assess the effects of Phen on post-trauma histochemical and behavioral changes. Animals were treated with Phen (2.5 mg/kg, IP, BID) for 5 days started on the day of injury and the effects were evaluated by behavioral and histological examinations at 1 and 2 weeks after injury. Phen significantly attenuated TBI-induced contusion volume, enlargement of the lateral ventricle, and behavioral impairments in motor asymmetry, sensorimotor functions, motor coordination, and balance functions. The morphology of microglia was shifted to an active from a resting form after TBI, and Phen dramatically reduced the ratio of activated to resting microglia, suggesting that Phen also mitigates neuroinflammation after TBI. While Phen has potent anti-acetylcholinesterase activity, its (+) isomer Posiphen shares many neuroprotective properties but is almost completely devoid of anti-acetylcholinesterase activity. We evaluated Posiphen at a similar dose to Phen and found similar mitigation in lateral ventricular size increase, motor asymmetry, motor coordination, and balance function, suggesting the improvement of these histological and behavioral tests by Phen treatment occur via pathways other than anti-acetylcholinesterase inhibition. However, the reduction of lesion size and improvement of sensorimotor function by Posiphen were much smaller than with equivalent doses of Phen. Taken together, these results show that post-injury treatment with Phen over 5 days significantly ameliorates severity of TBI. These data suggest a potential development of this compound for clinical use in TBI therapy.

[CSF shunting surgery in patients with post-traumatic hydrocephalus in the vegetative status and minimally conscious state: analysis of its efficacy and safety]

The development of post-traumatic hydrocephalus (PTH) after severe traumatic brain injury can cause, in some cases, severe impairment of consciousness and prevent rehabilitation of patients. The influence of cerebrospinal fluid (CSF) circulation disorders on processes of consciousness recovery is a fundamental problem that requires in-depth research. The issues of differential diagnosis, results of surgical treatment of PTH, and its complications in patients in the vegetative status (VS) and minimally conscious state (MCS) remain poorly covered.

MATERIAL AND METHODS

We performed a retrospective analysis of the long-term outcomes of surgical treatment in 82 PTH patients in the VS (38 cases) and MCS (44 cases).

RESULTS

A significant clinical improvement occurred in 60.6% of VS patients and in 65.9% of MCS patients. The rate of shunt infection was high and amounted to 21.05% in the group of VS patients and 20.4% in the group of MCS patients. The rate of shunt system dysfunction was 26.05% in the first group and 20.4% in the second group. Postoperative mortality (associated directly with treatment complications) was 3.6%. Total mortality was 10.9%.

DISCUSSION

The positive effect of shunting surgery in patients with gross impairment of consciousness was associated with transition to higher levels of consciousness. The high rate of complications, especially infections, was due to a serious condition of patients and comorbidities, in particular chronic infection foci. Shunt system dysfunction was not a factor of the adverse outcome of surgical treatment because rarely led to irreversible consequences, but required repeated surgery. Mortality after shunting surgery was significantly higher in patients with gross impairment of consciousness than in other groups of patients. We found a correlation between deaths in VS patients and shunt infection in the postoperative period.

CONCLUSION

CSF shunting surgery is an important step in surgical rehabilitation of PTH patients. To assess the contribution of various risk factors to the development of shunt infection and to develop measures reducing its rate, further prospective studies are needed.

Clinical Feature and Outcomes of Secondary Hydrocephalus Caused by Head Trauma

Objective

Post-traumatic hydrocephalus (PTH) is a frequent and serious complication following brain injury. The incidence of PTH varies greatly among studies. The purpose of this study was to investigate the incidence and treatment of PTH in patients with head trauma.

Methods

We examined 956 patients with head trauma who visited our center from January 2012 to December 2015. The hydrocephalus diagnosis was based on radiologic findings and clinical features, and patients were classified into the mild (Group 1, Glasgow Coma Scale score [GCS] 13–15), moderate (Group 2, GCS 9–12), or severe (Group 3, GCS 3–8) brain injury group according to their GCS at admission. To compare these groups, we used age, gender, radiologic findings, PTH developmental period, and postoperative results (Glasgow Outcome Scale).

Results

Of the 956 patients, 24 (2.5%) developed PTH. PTH occurred in 11 (1.4%), 3 (5.6%), and 10 (7.0%) patients in Groups 1, 2, and 3, respectively. Of the 24 patients with PTH, 22 (91.7%) developed PTH within 12 weeks post-trauma; the higher the GCS, the later the onset, and the lower the GCS, the earlier the onset (p=0.019). Twenty-one patients underwent ventriculoperitoneal shunting, and 13 had improved symptoms.

Conclusion

The incidence of PTH cannot be ignored. The possibility of PTH needs to be considered in patients with head trauma and appropriate follow-up should be undertaken. PTH is a treatable complication and patients' quality of life and neurological status can be improved if the appropriate treatment is selected and applied.

[Modern diagnostics and treatment of posttraumatic hydrocephalus]

One of the frequent consequences of severe traumatic brain injury is posttraumatic hydrocephalus that not only hampers the processes of consciousness recovery, rehabilitation, and social adaptation of patients but also is the cause of disability. Pathological processes underlying the clinical picture of posttraumatic hydrocephalus and the relationship between CSF circulation disorders and structural changes in the brain substance have not been adequately studied. Of particular importance are patients in the chronic vegetative or minimally conscious state, recovery from which is blocked by posttraumatic hydrocephalus. The question of reversibility of impaired consciousness depending on the disease duration has remained open. High risks of purulent-inflammatory complications of shunting surgery are especially important in patients with chronic infection foci (tracheostomy, gastrostomy, epicystostomy, prolonged bladder catheterization, pressure ulcers, etc.), but their actual effect on the shunting outcomes has not been revealed. Posttraumatic hydrocephalus remains a topical neurosurgical problem requiring clarification of its diagnostic criteria, differentiation from atrophy-related ventriculomegaly, and comprehensive development of pathogenetic and therapeutic aspects.

Factors associated with shunt-dependent hydrocephalus after decompressive craniectomy for traumatic brain injury

OBJECTIVE Posttraumatic hydrocephalus (PTH) affects 11.9%-36% of patients undergoing decompressive craniectomy (DC) and is an important cause of morbidity after traumatic brain injury (TBI). Early diagnosis and treatment of PTH can prevent further neurological compromise in patients who are recovering from TBI. There is limited data on predictors of shunting for PTH after DC for TBI. METHODS Prospectively collected data from the erythropoietin severe TBI randomized controlled trial were studied. Demographic, clinical, and imaging data were analyzed for enrolled patients who underwent a DC. All head CT scans during admission were reviewed and assessed for PTH by the Gudeman criteria or the modified Frontal Horn Index ≥ 33%. The presence of subdural hygromas was categorized as unilateral/bilateral hemispheric or interhemispheric. Using L1-regularized logistic regression to select variables, a multiple logistic regression model was created with ventriculoperitoneal shunting as the binary outcome. Statistical significance was set at p < 0.05. RESULTS A total of 60 patients who underwent DC were studied. Fifteen patients (25%) underwent placement of a ventriculoperitoneal shunt for PTH. The majority of patients underwent unilateral decompressive hemicraniectomy (n = 46, 77%). Seven patients (12%) underwent bifrontal DC. Unilateral and bilateral hemispheric hygromas were noted in 31 (52%) and 7 (11%) patients, respectively. Interhemispheric hygromas were observed in 19 patients (32%). The mean duration from injury to first CT scan showing hemispheric subdural hygroma and interhemispheric hygroma was 7.9 ± 6.5 days and 14.9 ± 11.7 days, respectively. The median duration from injury to shunt placement was 43.7 days. Multivariate analysis showed that the presence of interhemispheric hygroma (OR 63.6, p = 0.001) and younger age (OR 0.78, p = 0.009) were significantly associated with the need for a shunt after DC. CONCLUSIONS The presence of interhemispheric subdural hygromas and younger age were associated with shunt-dependent hydrocephalus after DC in patients with severe TBI.

Laquinimod attenuates inflammation by modulating macrophage functions in traumatic brain injury mouse model

Background

Traumatic brain injury (TBI) is a critical public health and socio-economic problem worldwide. A growing body of evidence supports the involvement of inflammatory events in TBI. It has been reported that resident microglia and infiltrating monocytes promote an inflammatory reaction that leads to neuronal death and eventually behavioral and cognitive impairment. Currently, there is no effective treatment for TBI and the development of new therapeutic strategies is a scientific goal of highest priority. Laquinimod, an orally administered neuroimmunomodulator initially developed for the treatment of multiple sclerosis, might be a promising neuroprotective therapy for TBI. Herein, we aim to investigate the hypothesis that laquinimod will reduce the central nervous system (CNS) damage caused by TBI.

Methods

To test our hypothesis, Ccr2^rfp/+Cx3cr1^gfp/+ mice were submitted to a moderate TBI induced by fluid percussion. Sham controls were submitted only to craniotomy. Mice were treated daily by oral gavage with laquinimod (25 mg/kg) 7 days before and 3 days after TBI. The brains of mice treated or not treated with laquinimod were collected at 3 and 120 days post injury, and brain morphological changes, axonal injury, and neurogenesis were evaluated by microscopy analysis. We also isolated microglia from infiltrating monocytes, and the expression of immune gene mRNAs were analyzed by employing a quantitative NanoString nCounter technique.

Results

Laquinimod prevented ventricle enlargement caused by TBI in the long term. Immunohistochemical analyses revealed decreased axonal damage and restored neurogenesis in the laquinimod-treated TBI group at early stage (3 days post injury). Notably, laquinimod inhibited the monocytes infiltration to the brain. Hierarchial clustering demonstrated that the microglial gene expression from the TBI group treated with laquinimod resembles the sham group more than the TBI-water control group.

Conclusions

Administration of laquinimod reduced lesion volume and axonal damage and restored neurogenesis after TBI. Laquinimod might be a potential therapy strategy to improve TBI long-term prognosis.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1075-y) contains supplementary material, which is available to authorized users.

Decompressive craniectomy and CSF disorders in children

INTRODUCTION

Decompressive craniectomy (DC) is a lifesaving procedure but is associated to several post-operative complications, namely cerebrospinal fluid (CSF) dynamics impairment. The aim of this multicentric study was to evaluate the incidence of such CSF alterations after DC and review their impact on the overall outcome.

MATERIAL AND METHODS

We performed a retrospective multicentric study to analyze the CSF disorders occurring in children aged from 0 to 17 years who had undergone a DC for traumatic brain injury (TBI) in the major Departments of Pediatric Neurosurgery of France between January 2006 and August 2016.

RESULTS

Out of 150 children, ranging in age between 7 months and 17 years, mean 10.75 years, who underwent a DC for TBI in 10 French pediatric neurosurgical centers. Sixteen (6 males, 10 females) (10.67%) developed CSF disorders following the surgical procedure and required an extrathecal CSF shunting. External ventricular drainage increased the risk of further complications, especially cranioplasty infection (p = 0.008).

CONCLUSION

CSF disorders affect a minority of children after DC for TBI. They may develop early after the DC but they may develop several months after the cranioplasty (8 months), consequently indicating the necessity of clinical and radiological close follow-up after discharge from the neurosurgical unit. External ventricular drainage and permanent CSF shunt placement increase significantly the risk of cranioplasty infection.

Hydrocephalus associated with childhood nonaccidental head trauma

OBJECTIVE

The incidence of posttraumatic ventriculomegaly (PTV) and shunt-dependent hydrocephalus after nonaccidental head trauma (NAHT) is unknown. In the present study, the authors assessed the timing of PTV development, the relationship between PTV and decompressive craniectomy (DC), and whether PTV necessitated placement of a permanent shunt. Also, NAHT/PTV cases were categorized into a temporal profile of delay in admission and evaluated for association with outcomes at discharge.

METHODS

The authors retrospectively reviewed the cases of patients diagnosed with NAHT throughout a 10-year period. Cases in which sequential CT scans had been obtained (n = 28) were evaluated for Evans' index to determine the earliest time ventricular dilation was observed. Discharge outcomes were assessed using the King's Outcome Scale for Childhood Head Injury score.

RESULTS

Thirty-nine percent (11 of 28) of the patients developed PTV. A low admission Glasgow Coma Scale (GCS) score predicted early PTV presentation (within < 3 days) versus a high GCS score (> 1 week). A majority of PTV/NAHT patients presented with a subdural hematoma (both convexity and interhemispheric) and ischemic stroke, but subarachnoid hemorrhage was significantly associated with PTV/NAHT (p = 0.011). Of 6 patients undergoing a DC for intractable intracranial pressure, 4 (67%) developed PTV (p = 0.0366). These patients tended to present with lower GCS scores and develop ventriculomegaly early. Only 2 patients developed hydrocephalus requiring shunt placement.

CONCLUSIONS

PTV presents early after NAHT, particularly after a DC has been performed. However, the authors found that only a few PTV/NAHT patients developed shunt-dependent hydrocephalus.

Posttraumatic Hydrocephalus as a Confounding Influence on Brain Injury Rehabilitation: Incidence, Clinical Characteristics, and Outcomes

OBJECTIVE

To describe incidence, clinical characteristics, complications, and outcomes in posttraumatic hydrocephalus (PTH) after traumatic brain injury (TBI) for patients treated in an inpatient rehabilitation program.

DESIGN

Cohort study with retrospective comparative analysis.

SETTING

Inpatient rehabilitation hospital.

PARTICIPANTS

All patients admitted for TBI from 2009 to 2013 diagnosed with PTH (N=59), defined as ventriculomegaly, delayed clinical recovery discordant with injury severity, hydrocephalus symptoms, or positive lumbar puncture results.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Primary measures were incidence of PTH and patient and injury characteristics. Secondary measures included frequency and timing of ventriculoperitoneal (VP) shunt, related complications, emergence from and duration of posttraumatic amnesia (PTA), Rancho Los Amigos Scale (RLAS) score, and FIM score at rehabilitation admission and discharge.

RESULTS

Of 701 patients with TBI admitted, 59 (8%) were diagnosed with PTH. Of these, the median age was 25 years, with 73% being men. At initial presentation, 52 (88%) did not follow commands. Fifty-two (90%) patients with PTH had a VP shunt placed. Median time from injury to shunt placement was 69 (range, 9-366) days. Seven (12%) patients with PTH experienced postsurgical seizure, 3 (6%) had shunt infection, and 7 (12%) had shunt malfunction. Thirty-six (61%) patients with PTH emerged from PTA during rehabilitation. Median total FIM score at rehabilitation admission was 20 (range, 18-76), and at discharge it was 43 (range, 18-118). Injury severity predicted outcome at rehabilitation admission, whereas shunt timing predicted outcome at rehabilitation discharge.

CONCLUSIONS

Incidence of PTH was observed in 8% of patients with TBI in inpatient rehabilitation. Earlier shunting predicted improved outcome during rehabilitation. Future studies should prospectively examine clinical decision rules, type, and timing of intervention and the coeffectiveness of rehabilitation treatment on outcomes.

Recovering two languages with the right hemisphere

Converging evidence suggests that the right hemisphere (RH) plays an important role in language recovery from aphasia after a left hemisphere (LH) lesion. In this longitudinal study we describe the neurological, cognitive, and linguistic profile of A.C., a bilingual who, after a severe traumatic brain injury, developed a form of fluent aphasia that affected his two languages (i.e., Romanian and Italian). The trauma-induced parenchymal atrophy led to an exceptional ventricular dilation that, gradually, affected the whole left hemisphere. A.C. is now recovering both languages relying only on his right hemisphere. An fMRI experiment employing a bilingual covert verb generation task documented the involvement of the right middle temporal gyrus in processes of lexical selection and access. This case supports the hypothesis that the RH plays a role in language recovery from aphasia when the LH has suffered massive lesions.

Homogeneous clusters of Alzheimer's disease patient population

Background

Identification of biomarkers for the Alzheimer’s disease (AD) is a challenge and a very difficult task both for medical research and data analysis.

Methods

We applied a novel clustering tool with the goal to identify subpopulations of the AD patients that are homogeneous in respect of available clinical as well as in respect of biological descriptors.

Results

The main result is identification of three clusters of patients with significant problems with dementia. The evaluation of properties of these clusters demonstrates that brain atrophy is the main driving force of dementia. The unexpected result is that the largest subpopulation that has very significant problems with dementia has besides mild signs of brain atrophy also large ventricular, intracerebral and whole brain volumes. Due to the fact that ventricular enlargement may be a consequence of brain injuries and that a large majority of patients in this subpopulation are males, a potential hypothesis is that such medical status is a consequence of a combination of previous traumatic events and degenerative processes.

Conclusions

The results may have substantial consequences for medical research and clinical trial design. The clustering methodology used in this study may be interesting also for other medical and biological domains.

Chronic Histopathological and Behavioral Outcomes of Experimental Traumatic Brain Injury in Adult Male Animals

The purpose of this review is to survey the use of experimental animal models for studying the chronic histopathological and behavioral consequences of traumatic brain injury (TBI). The strategies employed to study the long-term consequences of TBI are described, along with a summary of the evidence available to date from common experimental TBI models: fluid percussion injury; controlled cortical impact; blast TBI; and closed-head injury. For each model, evidence is organized according to outcome. Histopathological outcomes included are gross changes in morphology/histology, ventricular enlargement, gray/white matter shrinkage, axonal injury, cerebrovascular histopathology, inflammation, and neurogenesis. Behavioral outcomes included are overall neurological function, motor function, cognitive function, frontal lobe function, and stress-related outcomes. A brief discussion is provided comparing the most common experimental models of TBI and highlighting the utility of each model in understanding specific aspects of TBI pathology. The majority of experimental TBI studies collect data in the acute postinjury period, but few continue into the chronic period. Available evidence from long-term studies suggests that many of the experimental TBI models can lead to progressive changes in histopathology and behavior. The studies described in this review contribute to our understanding of chronic TBI pathology.

Computerized tomographic study of normal Evans index in adult Nigerians

Background:

The evaluation of degree of ventricular enlargement should be based on established indices rather than on personal experience as this is highly subjective. Our aim was to establish normal values for Evans index in a Nigerian adult population as none has been found in the Nigerian medical literature.

Materials and Methods:

Axial computerized tomographic brain scans of 488 normal subjects were reviewed retrospectively. Of them, 319 (65.36%) of the patients were males and 169 (34.63%) were females; their ages ranged from 18 to 84 years with a mean age of 37.26 years. The images were acquired using a multi-slice GE Sigma excite scanner. Evans index was measured as the linear ratio of the total width of the frontal horns of the cerebral lateral ventricles to the maximum intracranial diameter.

Results:

The mean value for Evans index for the studied population was 0.252 ± 0.04. The EI increased with age and it was slightly higher among males. The difference in Evans value in males and females was not statistically significant. Individuals above 60 years old had the highest Evans values in both sexes.

Conclusion:

This study has established ranges of normal value for Evans index in a Nigerian population. It agrees with the diagnostic cut-off value of > 0.3 for hydrocephalus and it compares well with that of the Caucasians.

The influence of decompressive craniectomy on the development of hydrocephalus: a review

Decompressive craniectomy (DC) is widely used to treat intracranial hypertension following traumatic brain injury (TBI) or cerebral vascular disease. Many studies have discussed complications of this procedure, and hydrocephalus is a common complication of DC. To further evaluate the relationship between DC and hydrocephalus, a review of the literature was performed. Numerous complications may arise after DC, including contusion or hematoma expansion, epilepsy, herniation of the cortex through a bone defect, CSF leakage through the scalp incision, infection, subdural effusion, hydrocephalus and “syndrome of the trephined”. Several hydrocephalus predictors were identified; these included DC, distance from the midline, hygroma, age, injury severity, subarachnoid or intraventricular hemorrhage, delayed time to craniotomy, repeated operation, and duraplasity. However, results differed among studies. The impact of DC on hydrocephalus remains controversial.

Is decompressive craniectomy a risk factor for ventriculomegaly?

OBJECTIVE

Decompressive craniectomy (DC) is an established therapeutic option following severe traumatic brain injury (TBI). However, several delayed complications of DC have been reported, including ventriculomegaly, which can lead to poor patient outcomes. Nevertheless, ventriculomegaly can occur after TBI even without DC. The aim of the present study was to investigate the influence of DC on ventriculomegaly.

MATERIAL AND METHODS

Adult male Sprague-Dawley rats (300-400 g) were subjected to lateral fluid percussion injury using a fluid percussion device. Rats were randomly divided into four groups: sham, craniectomized without trauma (D group), traumatized without DC (FPI group), and craniectomized immediately after trauma (FPI + D group). On day 28 of recovery, ventricular volumes were measured by image analysis.

RESULTS

There was no significant difference in ventricular size between the sham group and the D group animals or between the FPI group and the FPI + D group animals.

CONCLUSION

These data suggest that DC may not be a risk factor for ventriculomegaly after TBI.

Traumatic subarachnoid hemorrhage: our current understanding and its evolution over the past half century

Traumatic brain injury (TBI) is a common cause of morbidity and mortality in the US, especially among the young. Primary injury in TBI is preventable, whereas secondary injury is treatable. As a result, considerable research efforts have been focused on elucidating the pathophysiology of secondary injury and determining various prognosticators in the hopes of improving final outcome by minimizing secondary injury. One such variable, traumatic subarachnoid hemorrhage (tSAH), has been the focus of many discussions over the past half century as numerous clinical studies have shown tSAH to be associated with adverse outcome. Whether the relationship of tSAH with poorer outcome in TBI is merely an epiphenomenon or a result of direct cause and effect is unclear. Some investigators believe that tSAH is merely a marker of severer TBI, while others argue that it directly causes deleterious effects such as vasospasm and ischemia. At the present time, no proven treatment regimen aimed specifically at decreasing the detrimental effects of tSAH exists, although calcium channel blockers traditionally thought to target vasospasm have shown some promises. Given that tSAH may primarily be an early indicator of associated and evolving brain injury, vigilant diagnostic surveillance including serial head CT and prevention of secondary brain damage owing to hypotension, hypoxia and intracranial hypertension may be more cost-effective than attempting to treat potential adverse sequelae associated with tSAH.

Facilitated assessment of tissue loss following traumatic brain injury

All experimental models of traumatic brain injury (TBI) result in a progressive loss of brain tissue. The extent of tissue loss reflects the injury severity and can be measured to evaluate the potential neuroprotective effect of experimental treatments. Quantitation of tissue volumes is commonly performed using evenly spaced brain sections stained using routine histochemical methods and digitally captured. The brain tissue areas are then measured and the corresponding volumes are calculated using the distance between the sections. Measurements of areas are usually performed using a general purpose image analysis software and the results are then transferred to another program for volume calculations. To facilitate the measurement of brain tissue loss we developed novel algorithms which automatically separate the areas of brain tissue from the surrounding image background and identify the ventricles. We implemented these new algorithms by creating a new computer program (SectionToVolume) which also has functions for image organization, image adjustments and volume calculations. We analyzed brain sections from mice subjected to severe focal TBI using both SectionToVolume and ImageJ, a commonly used image analysis program. The volume measurements made by the two programs were highly correlated and analysis using SectionToVolume required considerably less time. The inter-rater reliability was high. Given the extensive use of brain tissue loss measurements in TBI research, SectionToVolume will likely be a useful tool for TBI research. We therefore provide both the source code and the program as attachments to this article.

Post-traumatic hypoxia exacerbates neurological deficit, neuroinflammation and cerebral metabolism in rats with diffuse traumatic brain injury

Background

The combination of diffuse brain injury with a hypoxic insult is associated with poor outcomes in patients with traumatic brain injury. In this study, we investigated the impact of post-traumatic hypoxia in amplifying secondary brain damage using a rat model of diffuse traumatic axonal injury (TAI). Rats were examined for behavioral and sensorimotor deficits, increased brain production of inflammatory cytokines, formation of cerebral edema, changes in brain metabolism and enlargement of the lateral ventricles.

Methods

Adult male Sprague-Dawley rats were subjected to diffuse TAI using the Marmarou impact-acceleration model. Subsequently, rats underwent a 30-minute period of hypoxic (12% O₂/88% N₂) or normoxic (22% O₂/78% N₂) ventilation. Hypoxia-only and sham surgery groups (without TAI) received 30 minutes of hypoxic or normoxic ventilation, respectively. The parameters examined included: 1) behavioural and sensorimotor deficit using the Rotarod, beam walk and adhesive tape removal tests, and voluntary open field exploration behavior; 2) formation of cerebral edema by the wet-dry tissue weight ratio method; 3) enlargement of the lateral ventricles; 4) production of inflammatory cytokines; and 5) real-time brain metabolite changes as assessed by microdialysis technique.

Results

TAI rats showed significant deficits in sensorimotor function, and developed substantial edema and ventricular enlargement when compared to shams. The additional hypoxic insult significantly exacerbated behavioural deficits and the cortical production of the pro-inflammatory cytokines IL-6, IL-1β and TNF but did not further enhance edema. TAI and particularly TAI+Hx rats experienced a substantial metabolic depression with respect to glucose, lactate, and glutamate levels.

Conclusion

Altogether, aggravated behavioural deficits observed in rats with diffuse TAI combined with hypoxia may be induced by enhanced neuroinflammation, and a prolonged period of metabolic dysfunction.