abstract: Intracranial pressure is an important parameter to monitor, and elevated intracranial pressure can be life threatening. Elevated intracranial pressure is indicative of distress in the brain attributed by conditions such as aneurysm, traumatic brain injury, brain tumor, hydrocephalus, stroke, or meningitis. Electrocorticography (ECoG) recordings are invaluable in understanding epilepsy and detecting seizure zones. However, ECoG electrodes cause a foreign body mass effect, swelling, and pneumocephaly, which results in elevation of intracranial pressure (ICP). Thus, the aim of this work is to design an intracranial pressure monitoring system that could augment ECoG electrodes. A minimally invasive, low-cost epidural intracranial pressure monitoring system is developed for this purpose, using a commercial pressure transducer available for biomedical applications. The system is composed of a pressure transducer, sensing cup, electronics, and data acquisition system. The pressure transducer is a microelectromechanical system (MEMS)-based die that works on piezoresistive phenomenon with dielectric isolation for direct contact with fluids. The developed system was bench tested and verified in an animal model to confirm the efficacy of the system for intracranial pressure monitoring. The system has a 0.1 mmHg accuracy and a 2% error for the 0-10 mmHg range, with resolution of 0.01 mmHg. This system serves as a minimally invasive (2 mm burr hole) epidural ICP monitor, which could augment existing ECoG electrode arrays, to simultaneously measure intracranial pressure along with the neural signals. This device could also be employed with brain implants that causes elevation in ICP due to tissue - implant interaction often leading to edema. This research explores the concept and feasibility for integrating the sensing component directly on to the ECoG electrode arrays. / Dissertation/Thesis / Masters Thesis Bioengineering 2015

Intracranial pressure (ICP) is an important monitoring modality in the clinical management of several neurological diseases carrying the risk of fatal intracranial hypertension. However, this parameter is not always considered due to its invasive assessment. In this scenario, a non-invasive estimation of ICP (nICP) may be essential, and indeed it has become a Holy Grail in Clinical Neurosciences: extensively searched, albeit never found. This thesis is devoted to the assessment, applications and development of transcranial Doppler (TCD)-based non-invasive methods for ICP and cerebral perfusion pressure (CPP) monitoring. The thesis is divided into three sections: I) The accuracy of existing TCD-based nICP estimators in various scenarios of varying ICP (traumatic brain injury, rise of ICP during plateau waves, and rise in ICP induced by infusion of cerebrospinal fluid during infusion test). The estimators of nICP consisted of a mathematical black box model, methods based on non-invasive CPP, and a method based on TCD pulsatility index. II) The feasibility of the best performing nICP estimator in clinical practice, including patients with closed TBI and brain midline shift, patients with acute liver failure during liver transplant surgery, and patients during non-neurosurgical surgery in the beach chair position. III) The description and assessment of a novel methodology for non-invasive assessment of cerebral perfusion pressure (nCPP) based on spectral arterial blood volume accounting. As main results, TCD-based non-invasive methods could replicate changes in direct ICP across time confidently, and could provide reasonable accuracy in comparison to the standard invasive techniques. Furthermore, in feasibility studies, nICP in association with other TCD physiological parameters provided a comprehensive interpretation of cerebral haemodynamics in conditions presenting impairment of cerebral blood flow circulation. The new method of nCPP estimation could identify changes in CPP across time reliably in conditions of decreasing and increasing CPP. These findings support the use of TCD-based nICP methods in a variety of clinical conditions requiring management of ICP and brain perfusion. More importantly, the low costs associated with nICP methods, since TCD is a widely available medical device, could contribute to its widespread use as a reliable alternative for ICP monitoring in everyday clinical practice.

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 95-109).

Patients with a brain injury must overcome a central neurological insult and a systematic metabolic response. The systematic response includes hypermetabolism, hypercatabolism, altered vascular permeability, increased hormone and cytokine release, altered gastric emptying, altered mineral metabolism and altered immune status. This response may initiate mechanisms which lead to secondary brain injury and may adversely affect the function of other organs. Last two decades have improved our knowledge of pathophysiology in patients with primary and secondary brain injury including traumatic contusions. In a moment of injury, primary brain injury which is traumatic contusion can not be therapeutically prevented it can only have a preventive effect. Secondary brain injury can be therapeutically affected although both types of injuries have common pathophysiological signs of disturbed metabolism on cells and subcellular level. Research methods based on molecular biology opens a new zone of research reaction of central neurological system for trauma or ischemia with effort to get involved immediately at the beginning of developing adverse pathophysiological cascade leading to a death of neurotic cell. The brain contusion is a primary centre of brain injury with anatomic changes which can be graphically proved. In...

The more we know about the circulation of CSF through ventricle system, brain parenchyma, subarachnoideal space and the development of intracranial pressure (ICP), the more we understand different pathologies and pathological processes of the central cervous system. The knowledge about the basic hydrodynamic charecteristics of craniospinal system is a key factor for understanding a wide range of pathological situations affecting CNS, these are for example intracranial hypertension, normal pressure hydrocephalus and syringomyelia. In the presented paper, we are presenting a newly developed measuring system Visionbrain that enables us to gain the biological data and consequently to analyse them. At the same time, the results of such measurements were used to specify the compertmental model of CSF circulation. The model devides craniospinal system into five divisions - two intracranial and three spinal. Such model is the third generation of this model and, compared to the older version, it includes two intracranial veins. Thanks to this stucture, the model enables us simultaneous modeling of heart and respiratory pulsations of CSF. Compared to the other published models, it also includes defined structure of spinal part. The model is derived using laws of conservation and it encompasses pressure...

Submitted by JOÃO AUGUSTO LEONEL DE SOUZA null (desouza.ja@gmail.com) on 2016-09-09T16:38:02Z No. of bitstreams: 1 Dissertação final.pdf: 1556586 bytes, checksum: e53dadd03ff83fdae3ae4b4e49d912ac (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-09-13T13:15:00Z (GMT) No. of bitstreams: 1 souza_jal_me_jabo.pdf: 1556586 bytes, checksum: e53dadd03ff83fdae3ae4b4e49d912ac (MD5) / Made available in DSpace on 2016-09-13T13:15:00Z (GMT). No. of bitstreams: 1 souza_jal_me_jabo.pdf: 1556586 bytes, checksum: e53dadd03ff83fdae3ae4b4e49d912ac (MD5) Previous issue date: 2016-05-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A mielografia é muito realizada na prática veterinária, entretanto, existem importantes efeitos adversos associados a ela. O objetivo da presente pesquisa foi avaliar os possíveis efeitos sobre a pressão subaracnoide, parâmetros cardiorrespiratórios (TC, FR, FC, PAS, PAD, PAM, EtCO2, SpO2, InspISO e FeISO) e do índice de pressão-volume (PVI) em ovelhas hígidas submetidas à mielografia lombar. Foram utilizados 8 ovinos fêmeas sadios, os quais foram pré-medicados com Midazolan (0,5 mg/Kg), indução anestésica com Propofol (3-6 mg/Kg) e manutenção anestésica com Isoflurano. Primeiramente, os animais foram submetidos à punção da cisterna magna para monitoramento da pressão subaracnoide (Sap). Ato contínuo, foi realizado a mielografia lombar por meio da aplicação de Iohexol (300 mg/mL, taxa de 4,1 mL/min e dose de 0,4 mL/Kg). Os momentos estudados foram: imediatamente após a estabilização anestésica (M0), durante a punção lombar (M1), dois, quatro e seis minutos após a aplicação do contraste (M2, M3 e M4, respectivamente). A Sap foi colhida imediatamente após à punção atlanto-occipital (Sap0), o maior valor durante a aplicação do meio de contraste (Sapmax), dois, quatro e seis minutos após a aplicação do meio de contraste (Sap2, Sap3 e Sap4, respectivamente). Constataram-se diferenças significativas a 5% de confiança entre os momentos as variáveis: TC, PAS, PAD, PAM, InspISO, FeISO Sap e PPC pelo teste de Tukey. Com a correlação de Pearson TC/FR, FC/SpO2, FC/FR, FR/PAS, FR/PAD, FR/PAM, FR/PPC, Sap/PAS, PAD/Sap, PAM/Sap, EtCO2/SPO2, EtCO2/InsplSO, PAD/PAS, PAS/PAM, PAM/PAD, FelSO/InsplSO e Sap/PPC. Com base nos resultados concluímos que os valores de PVI, para a espécie ovina, com a metodologia empregada foi de 17,91 mL. Durante a realização da mielografia lombar ocorre aumento significativo da Sap (média de 101,87 mmHg), provocando grave redução da PPC. / The myelography is very accomplished in veterinary practice, however there are significant adverse effects associated with it. The aim of this research was to evaluate the possible effects of subarachnoid pressure, cardiorespiratory parameters (TC, FR, FC, PAS, PAD, PAM, EtCO2, SpO2, InspISO and FeISO) and pressure-volume index (PVI) in sheep otherwise healthy undergoing lumbar myelography. 8 healthy female sheep were used, which were pre-medicated with midazolam (0.5 mg / kg) anesthetic induction with propofol (3-6 mg / kg) and anesthesia maintained with isoflurane. First, the animals were submitted to the puncture of the cisterna magna and pressure monitoring. Subsequently, the lumbar myelography was performed by application of iohexol (300 mg / ml at rate 4.1 ml / min and a dose of 0.4 ml / kg). The time points studied were: immediately after anesthetic stabilization (M0) during a lumbar puncture (M1), two, four and six minutes after application of contrast (M2, M3 and M4, respectively). Subarachnoid pressure (Sap) was taken immediately after the atlanto-occipital punch (Sap0), the largest value during application of the contrast medium (Sapmax), two, four and six minutes after application of the contrast medium (SAP2, Sap3 and Sap4, respectively). They found significant differences at 5% confidence between times the variables TC, PAS, PAD, PAM, InspISO, FeISO Sap and PPC by Tukey test. With the Pearson correlation TC/FR, FC/SpO2, FC/FR, FR/PAS, FR/PAD, FR/PAM, FR/PPC, Sap/PAS, PAD/Sap, PAM/Sap, EtCO2/SPO2, EtCO2/InsplSO, PAD/PAS, PAS/PAM, PAM/PAD, FelSO/InsplSO and Sap/PPC Based on the results we conclude that the PVI values for the sheep, the methodology employed was 17.91 mL, close to normal values for adults of the human species. While performing the lumbar myelography is significant increase in Sap (average of 101.87 mmHg), causing severe reduction in PPC.

AIMS OF STUDY: 1. To analyse the patients . who have been treated at Groote Schuur Hospital over the last seven years for Pseudotumor Cerebri. 2. To document the clinical features of this group of patients. 3. To determine the visual prognosis of this group. 4. To assess the forms of treatment that have been used in this group. 5. To review the literature with regard to: a) a comparison of the results of other studies with the present one. b) the pathophysiology of the condition. c) treatment of the syndrome. d) the visual prognosis of the syndrome.

The more we know about the circulation of CSF through ventricle system, brain parenchyma, subarachnoideal space and the development of intracranial pressure (ICP), the more we understand different pathologies and pathological processes of the central cervous system. The knowledge about the basic hydrodynamic charecteristics of craniospinal system is a key factor for understanding a wide range of pathological situations affecting CNS, these are for example intracranial hypertension, normal pressure hydrocephalus and syringomyelia. In the presented paper, we are presenting a newly developed measuring system Visionbrain that enables us to gain the biological data and consequently to analyse them. At the same time, the results of such measurements were used to specify the compertmental model of CSF circulation. The model devides craniospinal system into five divisions - two intracranial and three spinal. Such model is the third generation of this model and, compared to the older version, it includes two intracranial veins. Thanks to this stucture, the model enables us simultaneous modeling of heart and respiratory pulsations of CSF. Compared to the other published models, it also includes defined structure of spinal part. The model is derived using laws of conservation and it encompasses pressure...

Patients with a brain injury must overcome a central neurological insult and a systematic metabolic response. The systematic response includes hypermetabolism, hypercatabolism, altered vascular permeability, increased hormone and cytokine release, altered gastric emptying, altered mineral metabolism and altered immune status. This response may initiate mechanisms which lead to secondary brain injury and may adversely affect the function of other organs. Last two decades have improved our knowledge of pathophysiology in patients with primary and secondary brain injury including traumatic contusions. In a moment of injury, primary brain injury which is traumatic contusion can not be therapeutically prevented it can only have a preventive effect. Secondary brain injury can be therapeutically affected although both types of injuries have common pathophysiological signs of disturbed metabolism on cells and subcellular level. Research methods based on molecular biology opens a new zone of research reaction of central neurological system for trauma or ischemia with effort to get involved immediately at the beginning of developing adverse pathophysiological cascade leading to a death of neurotic cell. The brain contusion is a primary centre of brain injury with anatomic changes which can be graphically proved. In...

The brain, like many parts of the human body, can experience swelling, also known as cerebral edema. Cerebral edema may occur because of an injury, health related issues, tumors, or even high altitudes[1]. When cerebral edema occurs, a rise in intracranial pressure (ICP) becomes prevalent and may cause a serious threat. Without immediate treatment, increased intracranial pressure can prevent blood from flowing to the brain and depriving it of necessary oxygen it needs to function. A normal ICP is usually between 5-15 mmHg (666 Pa - 1333Pa). Any ICP observed to be above 20 mmHg (2666Pa) can be associated with brain ischemia and is usually treated[2, 3]. If prolonged, high intracranial pressures can be fatal. Current methods of measuring increased ICP are invasive and may involve drilling into the skull. Extreme invasive measures are not always suitable for certain situations. This thesis presents a study of a non-invasive sensor using piezoelectric PVDF wire to measure the ICP. The PVDF wire sensor is wrapped around the outer portion of the human head to measure the integrated hoop strain. Using this hoop strain, the pressure is then calculated from a known coupling factor of strain to pressure outputted from finite element modeling simulations. The coupling factor is then incorporated into a final calibration factor to calibrate the piezoelectric PVDF wire sensor from charge (Picocoulomb) to pressure (Pascal). These calibration factors are proven to be primarily dependent on the circumference of the human skull. Furthermore, part of this study analyzed the effectiveness and validity of the sensor due to asymmetries in the human skull. A comparison of analytical analysis results versus computational results using finite element modeling simulations show that the PVDF wire sensor neglects any asymmetries presented within the test subject. The results of this study show that this sensor will output correct ICP measurements of different subjects using appropriate calibration factors and is a viable option for measuring ICP non-invasively. / Master of Science