Hosing of a Long Relativistic Particle Bunch in Plasma

Experimental results show that hosing of a long particle bunch in plasma can be induced by wakefields driven by a short, misaligned preceding bunch. Hosing develops in the plane of misalignment, self-modulation in the perpendicular plane, at frequencies close to the plasma electron frequency, and are reproducible. Development of hosing depends on misalignment direction, its growth on misalignment extent and on proton bunch charge. Results have the main characteristics of a theoretical model, are relevant to other plasma-based accelerators and represent the first characterization of hosing.

Controlled Growth of the Self-Modulation of a Relativistic Proton Bunch in Plasma

A long, narrow, relativistic charged particle bunch propagating in plasma is subject to the self-modulation (SM) instability. We show that SM of a proton bunch can be seeded by the wakefields driven by a preceding electron bunch. SM timing reproducibility and control are at the level of a small fraction of the modulation period. With this seeding method, we independently control the amplitude of the seed wakefields with the charge of the electron bunch and the growth rate of SM with the charge of the proton bunch. Seeding leads to larger growth of the wakefields than in the instability case.

Film or mirror? The exploration of narratives during the road from recognition to recovery of addictive disorders

Introduction

The examination of the cinematic metanarrative provides many possibilities for recovery-oriented addiction consultation. The key to efficiency can be the approach of the recipient’s point of view and attitude, with which the client can interpret his own traumas and life story retrospectively.

Objectives

Our aim is to show that the recognition, the turning points, the acknowledgement and the recovery from addiction can be described as a model in the deep structure of recovery stories. Can narrative research explore more deeply the main stages of recovery andidentity shaping, with the possible use of the film’s narrative technique?

Methods

12 recovering addicts were interviewed who have been clean for at least 4 years. Interviews covered the years spent as addicts and the path to recovery using the method of deductive metanarrative analysis.

Results

Based on the results of the analysis, elements of the film narrative could be found together major psychoanalysis concepts and literary theory models in the semi-structured interviews. Emotion control dysregulation all appear in the stories. Together these can be traced to a summary narrative and a historical line. Furthermore, the addicted person as a hero, the compulsion to repeat and its spookiness, and the role of the helpers also appear in the retrospective narratives without exception.

Conclusions

The well-structured, coherent recovery stories help the recoverer to reconstruct their self, to make the behavioral change permanent, thus reducing the chances of relapse. The film narrative and toolkit provide an opportunity based on similarities with the narrator’s framework, which can strengthen the recovering identity.

Disclosure

No significant relationships.

Transition between Instability and Seeded Self-Modulation of a Relativistic Particle Bunch in Plasma

We use a relativistic ionization front to provide various initial transverse wakefield amplitudes for the self-modulation of a long proton bunch in plasma. We show experimentally that, with sufficient initial amplitude [≥(4.1±0.4)  MV/m], the phase of the modulation along the bunch is reproducible from event to event, with 3%-7% (of 2π) rms variations all along the bunch. The phase is not reproducible for lower initial amplitudes. We observe the transition between these two regimes. Phase reproducibility is essential for deterministic external injection of particles to be accelerated.

Possible relationships of addictive disorders and attention deficit hyperactivity disorder (ADHD)

Introduction

One of the most recent topics in addictive disorders is videogame-use disorder which is continuously under research, especially in adolescents. The specific structure of digital games (immortality, infinity, etc.) can sensitize adolescents to the development of problematic use. The number of researches about problematic video game use has increased significantly during the last decade. In 2013, this problem was included among “Disorders requiring further research” in DSM-5, and it was also included in ICD-11 as a separate diagnostic category in 2019.

Objectives

We review studies investigating the association between the co-occurrence of ADHD and video game use in adolescents. We attempt to summarize new theoretical approaches to video game use disorder and the areas of present research.

Methods

We conducted a literature search in 4 databases (PubMed, Medline, Google Scholar, Web of Science) using keywords (ADHD, adolescents, video game use disorder, internet addiction, game addiction) over the past 5 years. Exclusion criteria were the following: publication date before 2014, adult population, or comorbidity beside ADHD.

Results

The comorbidity of video game use disorder and ADHD was frequent. Primarily cross-sectional studies examined the presence of hyperactivity, attention deficit, and impulsivity symptoms separately. The presence of attention deficit clearly showed an association with the development of video game use disorder.

Conclusions

Adolescents diagnosed with ADHD have a greater possibility of developing video game use disorder and/or problematic psychoactive substance users. More attention should be paid to this comorbidity in not only the diagnostic process, but also in the development of prevention programs.

Disclosure

No significant relationships.

Proton Bunch Self-Modulation in Plasma with Density Gradient

We study experimentally the effect of linear plasma density gradients on the self-modulation of a 400 GeV proton bunch. Results show that a positive or negative gradient increases or decreases the number of microbunches and the relative charge per microbunch observed after 10 m of plasma. The measured modulation frequency also increases or decreases. With the largest positive gradient we observe two frequencies in the modulation power spectrum. Results are consistent with changes in wakefields' phase velocity due to plasma density gradients adding to the slow wakefields' phase velocity during self-modulation growth predicted by linear theory.

Proton-driven plasma wakefield acceleration in AWAKE

In this article, we briefly summarize the experiments performed during the first run of the Advanced Wakefield Experiment, AWAKE, at CERN (European Organization for Nuclear Research). The final goal of AWAKE Run 1 (2013-2018) was to demonstrate that 10-20 MeV electrons can be accelerated to GeV energies in a plasma wakefield driven by a highly relativistic self-modulated proton bunch. We describe the experiment, outline the measurement concept and present first results. Last, we outline our plans for the future. This article is part of the Theo Murphy meeting issue 'Directions in particle beam-driven plasma wakefield acceleration'.

It Is Not Necessary to Discontinue Seizure Threshold-Lowering Medications Prior to Myelography

BACKGROUND AND PURPOSE

There is no consensus on whether patients undergoing myelography should discontinue medications that could lower their seizure threshold. The purpose of this study was to document the most commonly prescribed seizure threshold-lowering medications in patients undergoing myelography and determine whether withholding such medications decreases the incidence of seizures.

MATERIALS AND METHODS

We performed a retrospective observational study of all the myelograms obtained in 2016 at 2 affiliated hospitals. At hospital A, seizure threshold-lowering medications are discontinued before myelography, and prophylactic diazepam is given for all cervical myelograms. At hospital B, seizure threshold-lowering medications are not withheld before the procedure, and medical seizure prophylaxis is not implemented. The seizure threshold-lowering medications the patients were taking at the time of the procedure and postmyelographic seizure incidence were documented.

RESULTS

A total of 311 patients underwent myelography during 2016. One hundred eleven patients (36%) were on at least 1 seizure threshold-lowering medication, and 30 (10%) were on at least 2. The most common medications were duloxetine, sertraline, venlafaxine, bupropion, and trazodone. The most common tricyclic antidepressant was amitriptyline. Three patients across both sites had a controlled seizure disorder and were on antiepileptics. None of the patients at either hospital had seizures during or within 3 hours following any of the myelograms during the study period.

CONCLUSIONS

Continuing seizure threshold-lowering medications during myelography does not increase the risk of seizures. Screening for and withholding seizure threshold-lowering medications are not indicated for routine myelography.

High-frequency forced oscillations in neuronlike elements

We analyzed a generic relaxation oscillator under moderately strong forcing at a frequency much greater that the natural intrinsic frequency of the oscillator. Additionally, the forcing is of the same sign and, thus, has a nonzero average, matching neuroscience applications. We found that, first, the transition to high-frequency synchronous oscillations occurs mostly through periodic solutions with virtually no chaotic regimes present. Second, the amplitude of the high-frequency oscillations is large, suggesting an important role for these oscillations in applications. Third, the 1:1 synchronized solution may lose stability, and, contrary to other cases, this occurs at smaller, but not at higher frequency differences between intrinsic and forcing oscillations. We analytically built a map that gives an explanation of these properties. Thus, we found a way to substantially "overclock" the oscillator with only a moderately strong external force. Interestingly, in application to neuroscience, both excitatory and inhibitory inputs can force the high-frequency oscillations.

Ducks in space: from nonlinear absolute instability to noise-sustained structures in a pattern-forming system

A subcritical pattern-forming system with nonlinear advection in a bounded domain is recast as a slow-fast system in space and studied using a combination of geometric singular perturbation theory and numerical continuation. Two types of solutions describing the possible location of stationary fronts are identified, whose origin is traced to the onset of convective and absolute instability when the system is unbounded. The former are present only for non-zero upstream boundary conditions and provide a quantitative understanding of noise-sustained structures in systems of this type. The latter correspond to the onset of a global mode and are present even with zero upstream boundary conditions. The role of canard trajectories in the nonlinear transition between these states is clarified and the stability properties of the resulting spatial structures are determined. Front location in the convective regime is highly sensitive to the upstream boundary condition, and its dependence on this boundary condition is studied using a combination of numerical continuation and Monte Carlo simulations of the partial differential equation. Statistical properties of the system subjected to random or stochastic boundary conditions at the inlet are interpreted using the deterministic slow-fast spatial dynamical system.

Canards in a minimal piecewise-linear square-wave burster

We construct a piecewise-linear (PWL) approximation of the Hindmarsh-Rose (HR) neuron model that is minimal, in the sense that the vector field has the least number of linearity zones, in order to reproduce all the dynamics present in the original HR model with classical parameter values. This includes square-wave bursting and also special trajectories called canards, which possess long repelling segments and organise the transitions between stable bursting patterns with n and n + 1 spikes, also referred to as spike-adding canard explosions. We propose a first approximation of the smooth HR model, using a continuous PWL system, and show that its fast subsystem cannot possess a homoclinic bifurcation, which is necessary to obtain proper square-wave bursting. We then relax the assumption of continuity of the vector field across all zones, and we show that we can obtain a homoclinic bifurcation in the fast subsystem. We use the recently developed canard theory for PWL systems in order to reproduce the spike-adding canard explosion feature of the HR model as studied, e.g., in Desroches et al., Chaos 23(4), 046106 (2013).

Response to interferon-beta treatment in multiple sclerosis patients: a genome-wide association study

Up to 50% of multiple sclerosis (MS) patients do not respond to interferon-beta (IFN-β) treatment and determination of response requires lengthy clinical follow-up of up to 2 years. Response predictive genetic markers would significantly improve disease management. We aimed to identify IFN-β treatment response genetic marker(s) by performing a two-stage genome-wide association study (GWAS). The GWAS was carried out using data from 151 Australian MS patients from the ANZgene/WTCCC2 MS susceptibility GWAS (responder (R)=51, intermediate responders=24 and non-responders (NR)=76). Of the single-nucleotide polymorphisms (SNP) that were validated in an independent group of 479 IFN-β-treated MS patients from Australia, Spain and Italy (R=273 and NR=206), eight showed evidence of association with treatment response. Among the replicated associations, the strongest was observed for FHIT (Fragile Histidine Triad; combined P-value 6.74 × 10^-6) and followed by variants in GAPVD1 (GTPase activating protein and VPS9 domains 1; combined P-value 5.83 × 10^-5) and near ZNF697 (combined P-value 8.15 × 10^-5).

Abstract W P87: Characteristics of T-cells Infiltrating Ruptured Intracranial Aneurysm

Introduction: Recently the role of adaptive immunity has been implied by microarray studies. But the results are contradictory. T-cell infiltration is a frequent histological finding in ruptured IA, T-cell phenotype, characteristic and true quantitation remains unknown. We preformed a prospective study to determine the subpopulation and expression of activation markers of T-cells infiltrating ruptured IA in relation to peripheral blood.

Hypothesis: IA have different subsets and activation levels of T-cells than peripheral blood.

Methods: We collected the tissue of ruptured IA of 8 patients operated on within 24 hours after subarachnoid hemorrhage symptoms onset. IA tissue was digested, stained with fluorescently labeled monoclonal antibodies and submitted to flow cytometry. In addition we collected and analyzed venous blood from 6 age, sex and risk factor-matched controls.

Results: CD4+ cells are less prevalent in IA tissue than in peripheral blood (42.14±17.28 vs. 65.88±5.32%; p=0.011), while there was no difference in CD8+ T-cells infiltrating IA (30.28±9.07 vs. 27.78±5.45%; p=0.585), and double negative (CD4-CD8-CD3+) T-cells were more prevalent in wall of IA than in circulation, (15.68±11.94 vs. 2.81±1.32%; p=0.026). Importantly, CD4+ infiltrating IA wall showed higher expression of HLA-DR (25.9±6.42 vs. 9.19± 3.58%; p<0.001) higher expression of CD 69 (26.8±19.66 vs. 2.73±0.93%; p=0.014). Similarly, there significantly more CD8+ cells showed HLA-DR+ in the IA than in blood. (45.96±15.57 vs. 22.47±11.46%; p=0.018) and CD69 (30.32±22.73 vs. 5.03±1.55%; p=0.022). Double negative cells in IA also had higher expression of HLA-DR (46.56±21.40 vs. 22.58±5.1%; p=0.025), CD69 (31.05±16.79 vs. 7.83±2.05%; p=0.016).

Conclusion: The tissue of ruptured IA is highly infiltrated by T-cells which show high expression of activation markers such as CD69 or HLA-DR. The importance of these cells to immunopathogenesis of intracranial aneurysm rupture should be further characterized.

Astrocytoma malignum in glioblastoma multiforme vertens with long term survival--case report and a literature review

Glioblastoma multiforme is the most common and most lethal pri- mary malignant tumor of the central nervous system. It can develop as a primary tumor or by transformation from its precursor--anaplastic astrocytoma which occurs less frequently but the prognosis is also unfavorable. Authors report a case of a 36-year-old man with "astrocytoma malignum in glioblastoma multiforme vertens" in the left frontal lobe. The mass, around 5 cm in diameter was resected by craniotomy 8 years ago. The patient received adiuvant radiation therapy concomitanly with temozolomide. He still stays asymptomatic, with no focal neurologic defects. There is no recurrence in the magnetic resonance imaging.

Inflection, canards and excitability threshold in neuronal models

A technique is presented, based on the differential geometry of planar curves, to evaluate the excitability threshold of neuronal models. The aim is to determine regions of the phase plane where solutions to the model equations have zero local curvature, thereby defining a zero-curvature (inflection) set that discerns between sub-threshold and spiking electrical activity. This transition can arise through a Hopf bifurcation, via the so-called canard explosion that happens in an exponentially small parameter variation, and this is typical for a large class of planar neuronal models (FitzHugh-Nagumo, reduced Hodgkin-Huxley), namely, type II neurons (resonators). This transition can also correspond to the crossing of the stable manifold of a saddle equilibrium, in the case of type I neurons (integrators). We compute inflection sets and study how well they approximate the excitability threshold of these neuron models, that is, both in the canard and in the non-canard regime, using tools from invariant manifold theory and singularity theory. With the latter, we investigate the topological changes that inflection sets undergo upon parameter variation. Finally, we show that the concept of inflection set gives a good approximation of the threshold in both the so-called resonator and integrator neuronal cases.

Interleukin 6-174G>C polymorphism and risk of aneurysmal subarachnoid hemorrhage: case-control study and meta-analysis

OBJECTIVES

Vascular inflammation contributes to the pathogenesis of aneurysmal subarachnoid hemorrhage (aSAH). Interleukin 6 (IL6) is a proinflammatory cytokine involved in many vascular pathologies. Two studies analyzing an association of the functional IL6 gene -174G>C promoter polymorphism with aSAH provided inconsistent results. The aim of this study was to investigate whether this IL6 polymorphism is associated with aSAH in a Polish population.

MATERIAL AND METHODS

We genotyped 276 aSAH patients and 581 unrelated control subjects. All were of Caucasian origin. In addition, a meta-analysis combining results of the current and previously published studies was conducted.

RESULTS

The distribution of IL6 genotypes and alleles did not differ significantly between aSAH (GG - 29.7%, GC - 50.0%, CC - 20.2%, G - 54.7%) and control subjects (GG - 32.0%, GC - 47.3%, CC - 20.7%, G - 44.3%). In the meta-analysis, the IL6-174G>C polymorphism was not associated with aSAH risk either.

CONCLUSIONS

We failed to find an association between the IL6 -174G>C polymorphism and aSAH in analyzed European populations.

Colloid cysts of the third ventricle. Endoscopic and open microsurgical management

BACKGROUND AND PURPOSE

The endoscopic approach to colloid cysts of the third ventricle is receiving increasing interest. However, its effectiveness is a matter of discussion. The aim of the study was to present direct and long-term outcome after endoscopy of colloid cyst vs microsurgery.

MATERIAL AND METHODS

Medical records of 23 patients with colloid cysts were retrospectively analyzed. This group consists of 10 patients treated endoscopically and 13 patients treated using a transcortical-transventricular approach. Sex and age distributions were similar in both groups. Clinically, symptoms of raised intracranial pressure predominated. All patients had hydrocephalus. Tumour diameter ranged from 1.5 to 3 cm. Mean follow-up period was 31 months.

RESULTS

In 6/10 endoscopically treated patients, tumours were completely removed. In 3 patients, small capsule remnants, adherent to the choroid plexus and veins, were left. In one case, a portion of capsule, obstructing the intraventricular foramen, was finally removed microsurgically. Postoperatively, 2 patients complained of memory deficits, which became permanent in one case. One patient developed temporary mutism. In one case, with symptoms of hydrocephalus without colloid cyst recurrence, a ventriculoperitoneal shunt was implanted 6 months after the initial surgery. In all microsurgically treated patients tumours were completely removed. One patient was reoperated because of intracerebral haematoma. Two patients suffered from temporary hemiparesis and 2 developed epilepsy. Within one year after surgery 3 patients were shunted because of hydrocephalus; one patient required antiepileptic treatment.

CONCLUSIONS

The endoscopic approach to colloid cysts of the third ventricle is safe, effective and carries a low complication rate. Endoscopy may be recommended as a treatment option.

[Comparison of two surgical methods as to early results in chronic subdural hematoma]

OBJECTIVE

Despite general agreement among neurosurgeons concerning operative treatment in chronic subdural hematoma (CSDH), the optimal procedure remains controversial. Two surgical approaches are available: evacuation of hematoma fluid by trepanation; craniotomy and removal of hematoma with surrounding membranes. The main goal of this study was to compare the results of treatment in CSDH depending on the method of surgery.

MATERIAL AND METHODS

This retrospective study was done basing on case histories and computed tomography findings in 433 patients with CSDH operated between 1983 and 2003 at the Department ofNeurotraumatology, Jagiellonian University. Altogether, 495 neurosurgical procedures were done. Hematoma was managed by burr hole evacuation in 333 cases and by craniotomy in 162 cases.

RESULT

Neurological grading on discharge indicated that trepanation produced significantly better results than craniotomy.

CONCLUSIONS

(1) In comparison with literature data and by separate evaluation, the results of treatment in CSDH at the Department of Neurotraumatology were good in trepanation and craniotomy groups alike. (2) Literature data and case histories of the present study demonstrate that burr hole evacuation is the preferred method of treatment in CSDH. (3) In the overwhelming majority of cases, computed tomography fails to identify CSDH patients necessitating craniotomy.

[Chronic subdural hematoma: a review of the literature. Part 1]

The first part of this publication is a review of the literature on the history, etiopathogenesis, clinical signs, and diagnosis of chronic subdural hematoma (CSDH). The incidence rate of CSDH is 2-11 cases per 100000 inhabitants. In spite of many anatomopathologic and biochemical studies, the pathomechanism of CSDH has not been fully explained. Although head computed tomography is the method of choice for the diagnosis of CSDH, magnetic resonance imaging can provide much more structural information on the hematoma. The pathophysiology of mental changes and hemiparesis in CSDH remains unclear. However, disturbances of cerebral haemodynamics seem to play a major role.

[Influence of anticoagulants on the appearance of chronic subdural hematoma]

In recent years in the Department of Neurotraumatology in Cracow it has been noticed the frequent connection between appearance of chronic subdural hematoma (CSDH) and treatment by anticoagulant medications. The aim of this study is to draw attention to the problem of insufficient control of anticoagulants consumption, especially by patients treated for cardiovascular system diseases that increases the risk of bleeding and CSDH development. The paper is based on data from questionnaires that was sent to patients with CSDH, cured in the Department of Neurotraumatology form 2004 to 2005. Analyzed was the group of 51 patients with chronic subdural hematoma; 37 individuals (72.5%) confirmed taking acetylsalicylic acid in the period of 3 months before admission to the Department, 9 (17.6%) patients answered that they were taking low-molecular weight heparin. One patient (1.9%) was taking chronically derivative of cumarin. The authors would inform that anticoagulant treatment might favour increase of chronic subdural hematoma incidence. It's especially important, because the average life expectancy has been prolonged in Poland and there are more people taking acetylsalicylic acid. This can be an epidemiological problem in future.

[Chronic subdural hematoma: a review of the literature. Part 2]

The second part of this review is concerned with methods and results of treatment in chronic subdural hematoma (CSDH). Surgical evacuation is the generally accepted approach to treatment in CSDH. There are two neurosurgical methods of evacuation: 1. Burr hole in the cranial vault and evacuation of hematoma fluid. 2. Craniotomy and removal of hematoma with surrounding membranes. According to the literature, priority should be given to burr hole evacuation of the hematoma on the following premises: 1. High effectiveness with lower risk of complications and better treatment outcome for trepanation. 2. Craniotomy with removal of hematoma membranes, although radical, does not eliminate the risk of recurrence of hematoma. 3. Reduction in the volume of hematoma fluid through the burr hole and drainage may lead to total resorption of hematoma together with membranes.

[A comparison of the results of treatment in young and elderly patients with chronic subdural hematoma depending on the method of surgery]

INTRODUCTION

Chronic subdural hematoma (CSDH) generally occurs in patients past the age of 50 years but may develop at any age, also in young persons. The aim of this study was to compare the results of treatment in young and elderly patients with CSDH depending on the method of surgery: burr hole (group A) or craniotomy (group B).

MATERIAL AND METHODS

This retrospective study was based on medical histories and computed tomography findings in patients with CSDH operated at the Department of Neurotraumatology, Jagiellonian University, in 1983-2003. Altogether, 114 patients were analyzed including 35 (30.7%) patients under the age of 40 years and 79 (69.3%) patients over the age of 75 years.

RESULTS

A significant correlation between the result of treatment and age of patients with CSDH was demonstrated. The best result (Glasgow Outcome Scale = 5) was achieved in 73.9% of young patients in the trepanation group and in 66.7% in the craniotomy group as opposed to just 15.5% of elderly patients in the trepanation group and 4.8% in the craniotomy group. The difference between young and elderly patients was significant (p = 0.00001 for burr hole surgery, p = 0.0006 for craniotomy). Burr hole evacuation offered better results than craniotomy.

CONCLUSIONS

(1) The results of treatment were much better in young than in elderly patients. (2) Comparison of the results of treatment of chronic subdural hematoma shows that burr hole surgery is the preferable procedure.

Morphological aspects of the traumatic chronic subdural hematoma capsule: SEM studies

The morphology of the outer and inner membranes of traumatic chronic subdural hematomas (CSDHs) surgically removed from eight patients was investigated by scanning electron microscopy (SEM). Hematomas were divided into three groups based on time that had passed from the initiation of trauma to surgery. Structure of the CSDHs showed gradual morphological changes of the developing hematoma capsule. They initially included angiogenic and aseptic inflammatory reactions followed by progressive involvement of fibroblasts-proliferating and producing collagen fibrils. Numerous capillaries suggesting formation of new blood vessels were observed mainly in young hematomas removed between 15 and 21 days after trauma. In "older" hematomas (40 days after trauma), more numerous capillaries and thin-walled sinusoids were accompanied by patent, larger diameter blood vessels. Within the fibrotic outer membrane of the "oldest" hematoma capsules (60 or more days after trauma), especially in the area over the hematoma cavity, blood vessels were frequently occluded by clots. The results suggest dynamic changes in cellular and vascular organization of traumatic CSDH capsules paralleling the progression in hematoma age.

[Results of multidisciplinary treatment of frontal sinus fractures]

BACKGROUND AND PURPOSE

The aim of the study was to present the results of our management of frontal sinus fractures.

MATERIALS AND METHODS

We analyzed records of 101 patients treated between 1996 and 2002, who sustained frontal sinus fractures. 7 patients were women and 94 were men. The average age of patients was 34 years. We analysed: circumstance of frontal sinus injury, frontal sinus fracture patterns, associated facial tissue and bone injuries, central nervous system injuries, perioperative management, timing of operation, surgical procedures and complications.

RESULTS

30 patients had anterior table fractures (type I), 51 had anterior and posterior table fractures (type II = 50, type IV = 1), 20 had posterior table fractures (type III). 22 patients were managed medically, 79 surgically. In 74 cases a combined, one-stage surgical procedure with neurosurgeons was performed, in 4 cases with an ophthalmologist, in 31 cases associated facial bone fractures were surgically managed. The average length of hospitalization was 16 days. There were 19 cases (24%) of postoperative complications, mostly early and late CSF leakage (12 patients). Inflammatory complications included acute frontal sinusitis (3 patients) and postoperative wound infection (1 patient).

CONCLUSIONS

Multidisciplinary one-stage surgical treatment of patients suffering from frontal sinus fractures associated with central nervous system and facial injuries optimizes treatment results and minimizes postoperative complications. A significant reduction in early and late postoperative inflammatory complications confirms the efficiency of nasofrontal duct recanalization with frontal sinus reconstruction.

[The role of computerized rheoencephalography in the assessment of normal pressure hydrocephalus. Preliminary report]

BACKGROUND AND PURPOSE

It is generally agreed that the positive result of lumbar cerebrospinal fluid (CSF) withdrawal offers a reliable means for selection of patients likely to respond to shunting in normal pressure hydrocephalus (NPH). However the studies of cerebral hemodynamics in NPH are performed Routinely only in few neurosurgical centers. We therefore studied the effect of CSF withdrawal on cerebrovascular autoregulation (CVA) in this condition by means of computerized rheoencephalography [REG].

MATERIAL AND METHODS

The study group consisted of 27 patients with presumed posttraumatic NPH. In each patient both the tap test and infusion test were performed. Psychometric tests and rheoencephalographic examinations were made twice: before and after CSF withdrawal. The obvious restoration of the functional state of CVA after CSF withdrawal was considered as a positive result of the tap test.

RESULTS

Fourteen patients with a positive tap test and/or with resistance to CSF outflow (Rout) of more than 11 mmHg/ml/min were shunted. The improvement was obtained in 10 of them. Only one patient with a positive tap test did not improve.

CONCLUSIONS

Our study suggests that restoration of CVA after CSF withdrawal is associated with high likelihood of shunt success, but not vice versa. Evaluation of CVA using REG seems to offer a new diagnostic tool in selecting patients likely to respond to shunting. Further studies are necessary to optimize the amount of CSF withdrawal, the delay between CSF withdrawal and control examinations and methodology of neuropsychological examinations.

[Prognostic value of computerized rheoencephalography in chronic posttraumatic subdural hematoma: a preliminary report]

BACKGROUND AND PURPOSE

The results of treatment of chronic subdural hematoma (CSDH) are still regarded as unsatisfactory. Measurements of cerebral hemodynamics are increasingly used to elucidate the pathophysiology of mental disturbances and hemiparesis in CSDH. On the other hand the clinical studies of cerebrovascular autoregulation in this condition are almost nonexistent. This study was therefore conducted to assess the cerebral artery compliance and the status of the autoregulatory reserve in CSDH as well as their effect on the neurological outcome.

MATERIAL AND METHODS

Ten patients with posttraumatic CSDH were studied. The status of cerebrovascular autoregulation and compliance of arteries were investigated using computerized rheoencephalography (REG). A classification of the pulse waveform (REGpw) has been devised according to the number of inflection points in the ascending branch. The normal cases have corresponded with only one inflection point (category I). The presence of three or more inflection points was thought as characteristic for regressive changes of the arterial wall (category II). The capacity of autoregulatory reserve was estimated by studying the changes in amplitude of REGpw as a response to upper body-down tilting.

RESULTS

In all patients the REG examination revealed a reduction in autoregulatory reserve. In 3 patients with the worst clinical result of treatment bilateral impairment of cerebrovascular autoregulation was found. The reduction in compliance of arteries was revealed in 6 patients.

CONCLUSIONS

Our preliminary results indicate that bilateral impairment of the cerebral blood flow and the decrease in arterial compliance are of prognostic significance in patients with CSDH.

[Circadian rhythms of melatonin of patients with severe traumatic brain injury]

The study was performed on a group of 5 patients with severe traumatic brain injury and in 2 healthy volunteers as the controls. The examination began 2-5 days after injury. The management of the patients and controls did not affect the natural melatonin circadian rhythm. The first result obtained was the characteristic nocturnal increase of the melatonin level in the healthy subjects. In a group of 5 patients with the severe traumatic brain injury the differences between the day and night time were insignificant. The results of the present study indicate that the severe brain injury gives rise to serious disturbances of the melatonin secretion in the acute posttraumatic period. These disturbances are characterized by the absence of the natural melatonin circadian rhythm. Despite the small number of patients, the obtained results justify further studies.