Biomedical Engineering and Bioengineering Commons^™

Visual Complexity Of The Time-Frequency Image Pinpoints The Epileptogenic Zone: An Unsupervised Deep-Learning Tool To Analyze Interictal Intracranial Eeg, Sarvagya Gupta

Graduate Masters Theses

Epilepsy, a prevalent neurological disorder characterized by recurrent seizures, continues to pose significant challenges in diagnosis and treatment, particularly among children. Despite substantial advancements in medical technology and treatment modalities, localization of the part of brain that causes seizures (Epileptogenic Zone) remains a difficult task. Intracranial EEG (iEEG) is often used to estimate the epileptogenic zone (EZ) in children with drugresistant epilepsy (DRE) and target it during surgery. Conventionally, iEEG signals are inspected in the time domain by human experts aiming to locate epileptiform activity.

Visual scrutiny of the iEEG time-frequency (TF) images can be an alternative way to review …

Seizure Detection Using Deep Learning, Information Theoretic Measures And Factor Graphs, Bahareh Salafian

Electronic Thesis and Dissertation Repository

Epilepsy is a common neurological disorder that disrupts normal electrical activity in the brain causing severe impact on patients’ daily lives. Accurate seizure detection based on long-term time-series electroencephalogram (EEG) signals has gained vital importance for epileptic seizure diagnosis. However, visual analysis of these recordings is a time-consuming task for neurologists. Therefore, the purpose of this thesis is to propose an automatic hybrid model-based /data-driven algorithm that exploits inter-channel and temporal correlations. Hence, we use mutual information (MI) estimator to compute correlation between EEG channels as spatial features and employ a carefully designed 1D convolutional neural network (CNN) to extract …

An Investigation Into The Development Of A Low Cost, Easy To Use Seizure Analysis Tool., Cody Dean

Masters Theses

The need for collaborating and sharing data and research between doctors, researchers, universities and patients has never been more necessary. We are seeing firsthand how a deadly virus can completely devastate the world in a matter of months and being able to react quickly is the top priority. Open source tools are making it possible to share research and learnings about viruses like COVID-19 across countries, industries, and universities and these tools and philosophies extend across all areas of medical research.

The amount of data that is being collected within the medical industry is increasing at an exponential rate and …

High Frequency Oscillations In The Epileptic Brain: Accurate Detection, Effect Of Vigilance State, And Sample Size Considerations, Amir Fared Partu Al-Bakri

Theses and Dissertations--Biomedical Engineering

About a third of all epilepsy patients may experience seizures that are resistant to medication. Surgical resection may be an option for some of these patients, but localization of the epileptogenic zone is difficult and expensive. For this process, the seizures must be observed and recorded in a clinical setting over several days. High-frequency oscillations (HFOs) have emerged as a possible biomarker for predicting the epileptogenic zone from a brief interictal recording of brain electrical activity without having to wait for seizures. The broad objective of this dissertation is to devise methods and criteria for accurate detection, sampling and localization …

Differentiating Epileptic From Psychogenic Nonepileptic Eeg Signals Using Time Frequency And Information Theoretic Measures Of Connectivity, Sarah Barnes

Masters Theses

Differentiating psychogenic nonepileptic seizures from epileptic seizures is a difficult task that requires timely recording of psychogenic events using video electroencephalography (EEG). Interpretation of video EEG to distinguish epileptic features from signal artifacts is error prone and can lead to misdiagnosis of psychogenic seizures as epileptic seizures resulting in undue stress and ineffective treatment with antiepileptic drugs. In this study, an automated surface EEG analysis was implemented to investigate differences between patients classified as having psychogenic or epileptic seizures. Surface EEG signals were grouped corresponding to the anatomical lobes of the brain (frontal, parietal, temporal, and occipital) and central coronal …

A Framework For Evaluating Cortical Architectural Anomalies In Temporal Lobe Epilepsy Patients, Hossein Rajali

Electronic Thesis and Dissertation Repository

Focal cortical dysplasia (FCD) are localized regions of malformed cerebral cortex that are frequently associated with drug-resistant epilepsy. Currently, there is a lack of research towards providing quantitative methods for characterizing minor abnormalities in cortical architecture, hindering efforts to determine whether removal affects surgical outcome, and define potential imaging correlates. In our work, we have developed a tool to extract relevant features associated with cortical architectural abnormalities that can deal with artifacts including cortical layer distortions and morphological differences caused by cortical folding effects, and processing artifacts due to improper sectioning. This framework was applied to detect abnormalities across multiple …

Connectivity Analysis Of Electroencephalograms In Epilepsy, Panuwat Janwattanapong

FIU Electronic Theses and Dissertations

This dissertation introduces a novel approach at gauging patterns of informa- tion flow using brain connectivity analysis and partial directed coherence (PDC) in epilepsy. The main objective of this dissertation is to assess the key characteristics that delineate neural activities obtained from patients with epilepsy, considering both focal and generalized seizures. The use of PDC analysis is noteworthy as it es- timates the intensity and direction of propagation from neural activities generated in the cerebral cortex, and it ascertains the coefficients as weighted measures in formulating the multivariate autoregressive model (MVAR). The PDC is used here as a feature extraction …

Brain Connectivity Networks For The Study Of Nonlinear Dynamics And Phase Synchrony In Epilepsy, Hoda Rajaei

FIU Electronic Theses and Dissertations

Assessing complex brain activity as a function of the type of epilepsy and in the context of the 3D source of seizure onset remains a critical and challenging endeavor. In this dissertation, we tried to extract the attributes of the epileptic brain by looking at the modular interactions from scalp electroencephalography (EEG). A classification algorithm is proposed for the connectivity-based separation of interictal epileptic EEG from normal. Connectivity patterns of interictal epileptic discharges were investigated in different types of epilepsy, and the relation between patterns and the epileptogenic zone are also explored in focal epilepsy.

A nonlinear recurrence-based method is …

Identification Of The Seizure Onset Zone By Auto-Regressive Model Residual Modulation Applied To Intracranial Eeg And Its Correlation To Channels With High Preponderances Of Detected Hfos, Allison L. Rogutich

Masters Theses

The objective of this thesis was to examine the ability of the Autoregressive Model Residual Modulation (ARRm) method to identify the Seizure Onset Zone (SOZ) in intracranial electroencephalogram (iEEG) of patients with refractory epilepsy. Patients who have not become seizure free after multiple trials of antiepileptic drugs (AEDs) may seek treatment through epilepsy surgery. Cortical electrodes are implanted directly on the cerebral cortex, then iEEG is collected. A specialized neurologist reviews the iEEG, then in consultation with the neurosurgeon, the SOZ is determined and areas of the brain may be chosen for resection. The success rate of epilepsy surgery varies, …

Sleep And Thermoregulation: A Study Of The Effect Of Ambient Temperature Manipulation On Mouse Sleep Architecture, Asma'a A. Ajwad

Theses and Dissertations--Biomedical Engineering

Good quality sleep is essential for mental and physical health. Inadequate sleep impacts memory consolidation, learning and cognition, immune function, autonomic regulation, physical performance, and other vital functions. In many neurological disorders that are associated with sleep problems such as epilepsy and Alzheimer’s disease, changes in brain circuitry affect sleep-wake regulation mechanisms; this is reflected in anomalous sleep-wake architecture and usually accompanied by poor sleep depth. Thus, over many years, many approaches have been tried in humans and animal models with the goal of improving sleep quality. Unfortunately, each of those approaches comes with limitations or side effects. Thus, there …

Developing An Imaging Biomarker To Detect Aberrant Brain Connectivity In Individual Patients, Esther Cox

Master's Theses (2009 -)

Resting state functional MRI (rsfMRI) has been proven to be a valuable tool in clinical applications such as pre-surgical mapping, but there is not yet a functional and usable algorithm that can be used by physicians in a clinical setting to evaluate an individual patient for diseases and aberrant brain connectivity. If a physician wants to evaluate a patient in this way, the rsfMRI data must be looked at “by hand,” i.e. the physician must manually evaluate the data and identify the functional ICN’s and whether they are normal or aberrant. An algorithm that would automate this process and supplement …

Histological Quantification In Temporal Lobe Epilepsy, Charlotte Anne Blinston

Electronic Thesis and Dissertation Repository

Approximately 30 percent of epilepsy patients suffer from refractory temporal lobe epilepsy which is commonly treated with resection of the epileptogenic tissue. However, surgical treatment presents many challenges in locating the epileptogenic focus and thus not all patients become seizure-free following surgery. Advances in techniques can lead to improved localization of the epileptogenic zone and may be validated by correlating MRI with neuropathology of the excised cortical tissue. Focal cortical dysplasias are a neuropathological group of cortical malformations that are often found in cases of refractory epilepsy, however, they are subtle and difficult to quantify. The purpose of this research …

Generalized Partial Directed Coherence And Centrality Measures In Brain Networks For Epileptogenic Focus Localization, Joshua Aaron Adkinson

Doctoral Dissertations

Accurate epileptogenic focus localization is required prior to surgical resection of brain tissue for treatment of patients with intractable temporal lobe epilepsy, a clinical need that is partially fulfilled to date through a subjective, and at times inconclusive, evaluation of the recorded electroencephalogram (EEG). Using brain connectivity analysis, patterns of causal interactions between brain regions were derived from multichannel EEG of 127 seizures in nine patients with focal, temporal lobe epilepsy (TLE). The statistically significant directed interactions in the reconstructed brain networks were estimated from three second intracranial multi-electrode EEG segments using the Generalized Partial Directed Coherence (GPDC) and validated …

Histological Characterization Of Inter Ictal Epileptiform Discharges Generating Brain Regions Using A Preclinical Model Of Focal Cortical Dysplasia, Abhay S. Deshmukh

FIU Electronic Theses and Dissertations

Current clinical practice of resective surgery in focal epilepsy involves electroencephalogram (EEG) brain source imaging to localize irritative brain areas from where Inter-ictal epileptiform discharges (IEDs) emerge, useful to localize the seizures-onset zones. Unfortunately, there are no previous systematic studies to characterize the pathophysiological mechanisms and abnormal cellular substrates in these irritative areas since histological data are available only from the final resective zones. To address this issue we applied a combination of EEG brain imaging described by Bae et al. (2015) using cutting-edge technology for high-density scalp EEG in rodents and histological analysis on a chronic rat model of …

The Effects Of Vagus Nerve Stimulation On Neuroinflammation In Epilepsy, Elizabeth A. St. Clair, Gabriel O Albors, Pedro Irazoqui Dr., Amy Brewster

The Summer Undergraduate Research Fellowship (SURF) Symposium

Epilepsy is a neurological disorder characterized by chronic, unexplainable seizures. Recurring epileptic seizures are associated with long-term structural damage and cognitive deficits, and can even lead to sudden, unexplainable death. Approximately 30% of epilepsy cases are not responsive to medication. Epileptic seizures often induce inflammation in the brain and may increase the frequency of future seizures, resulting in a detrimental cycle. Vagus nerve stimulation (VNS) is a non-pharmaceutical treatment method for epilepsy that has been shown to reduce inflammation in peripheral pathways. The role of VNS in the modulation of neuroinflammation has yet to be demonstrated experimentally. To explore this, …

Human Intracranial High Frequency Oscillation Detection Using Time Frequency Analysis And Its Relation To The Seizure Onset Zone, Riazul Islam

Masters Theses

One third of the patients diagnosed with focal epilepsy do not respond to antiepileptic drugs. For these patients the possible diagnosis options to give seizure freedom or at least reduce seizure frequencies significantly would be surgical resection or seizure interrupting implantable devices. The success of these procedures depends on accurate detection of the region causing seizure also known as epileptic zone. This requires detail pre-surgical evaluation including Invasive Video Electroencephalographic Monitoring (IVEM). The resulting great volume of intracranial Electroencephalography (iEEG) signal is visually examined by an expert epileptologist which can be time consuming, extremely complex, and not always effective. We …

Intraoperative Guidance For Pediatric Brain Surgery Based On Optical Techniques, Yinchen Song

FIU Electronic Theses and Dissertations

For most of the patients with brain tumors and/or epilepsy, surgical resection of brain lesions, when applicable, remains one of the optimal treatment options. The success of the surgery hinges on accurate demarcation of neoplastic and epileptogenic brain tissue. The primary goal of this PhD dissertation is to demonstrate the feasibility of using various optical techniques in conjunction with sophisticated signal processing algorithms to differentiate brain tumor and epileptogenic cortex from normal brain tissue intraoperatively.

In this dissertation, a new tissue differentiation algorithm was developed to detect brain tumors in vivo using a probe-based diffuse reflectance spectroscopy system. The system …

Multivariate Analysis Of Mr Images In Temporal Lobe Epilepsy, Diego H. Cantor-Rivera

Electronic Thesis and Dissertation Repository

Epilepsy stands aside from other neurological diseases because clinical patterns of progression are unknown: The etiology of each epilepsy case is unique and so it is the individual prognosis. Temporal lobe epilepsy (TLE) is the most frequent type of focal epilepsy and the surgical excision of the hippocampus and the surrounding tissue is an accepted treatment in refractory cases, specially when seizures become frequent increasingly affecting the performance of daily tasks and significantly decreasing the quality of life of the patient. The sensitivity of clinical imaging is poor for patients with no hippocampal involvement and invasive procedures such as the …

Experimental-Computational Analysis Of Vigilance Dynamics For Applications In Sleep And Epilepsy, Farid Yaghouby

Theses and Dissertations--Biomedical Engineering

Epilepsy is a neurological disorder characterized by recurrent seizures. Sleep problems can cooccur with epilepsy, and adversely affect seizure diagnosis and treatment. In fact, the relationship between sleep and seizures in individuals with epilepsy is a complex one. Seizures disturb sleep and sleep deprivation aggravates seizures. Antiepileptic drugs may also impair sleep quality at the cost of controlling seizures. In general, particular vigilance states may inhibit or facilitate seizure generation, and changes in vigilance state can affect the predictability of seizures. A clear understanding of sleep-seizure interactions will therefore benefit epilepsy care providers and improve quality of life in patients. …

Magnetic Resonance Imaging And Histology Correlation In The Neocortex In Temporal Lobe Epilepsy., Maged Goubran, Robert R Hammond, Sandrine De Ribaupierre, Jorge G Burneo, Seyed Mirsattari, David A Steven, Andrew G Parrent, Terry M Peters, Ali R Khan

Robarts Imaging Publications

OBJECTIVE: To investigate the histopathological correlates of quantitative relaxometry and diffusion tensor imaging (DTI) and to determine their efficacy in epileptogenic lesion detection for preoperative evaluation of focal epilepsy.

METHODS: We correlated quantitative relaxometry and DTI with histological features of neuronal density and morphology in 55 regions of the temporal lobe neocortex, selected from 13 patients who underwent epilepsy surgery. We made use of a validated nonrigid image registration protocol to obtain accurate correspondences between in vivo magnetic resonance imaging and histology images.

RESULTS: We found T1 to be a predictor of neuronal density in the neocortical gray matter (GM) …

Registration Of In-Vivo To Ex-Vivo Mri Of Surgically Resected Specimens: A Pipeline For Histology To In-Vivo Registration., Maged Goubran, Sandrine De Ribaupierre, Robert R Hammond, Catherine Currie, Jorge G Burneo, Andrew G Parrent, Terry M Peters, Ali R Khan

Robarts Imaging Publications

BACKGROUND: Advances in MRI have the potential to improve surgical treatment of epilepsy through improved identification and delineation of lesions. However, validation is currently needed to investigate histopathological correlates of these new imaging techniques. The purpose of this work is to develop and evaluate a protocol for deformable image registration of in-vivo to ex-vivo resected brain specimen MRI. This protocol, in conjunction with our previous work on ex-vivo to histology registration, completes a registration pipeline for histology to in-vivo MRI, enabling voxel-based validation of novel and existing MRI techniques with histopathology.

NEW METHOD: A combination of image-based and landmark-based 3D …

Quantitative Relaxometry And Diffusion Mri For Lateralization In Mts And Non-Mts Temporal Lobe Epilepsy., Ali R Khan, Maged Goubran, Sandrine De Ribaupierre, Robert R Hammond, Jorge G Burneo, Andrew G Parrent, Terry M Peters

Robarts Imaging Publications

We developed novel methodology for investigating the use of quantitative relaxometry (T1 and T2) and diffusion tensor imaging (DTI) for lateralization in temporal lobe epilepsy. Patients with mesial temporal sclerosis confirmed by pathology (N=8) and non-MTS unilateral temporal lobe epilepsy (N=6) were compared against healthy controls (N=19) using voxel-based analysis restricted to the anterior temporal lobes, and laterality indices for each MRI metric (T1, T2, fractional anisotropy (FA), mean diffusivity, axial and radial diffusivities) were computed based on the proportion of significant voxels on each side. The diffusivity metrics were the most lateralizing MRI metrics in MTS and non-MTS subsets, …

Detection Of Temporal Lobe Epilepsy Using Support Vector Machines In Multi-Parametric Quantitative Mr Imaging., Diego Cantor-Rivera, Ali R Khan, Maged Goubran, Seyed M Mirsattari, Terry M Peters

Robarts Imaging Publications

The detection of MRI abnormalities that can be associated to seizures in the study of temporal lobe epilepsy (TLE) is a challenging task. In many cases, patients with a record of epileptic activity do not present any discernible MRI findings. In this domain, we propose a method that combines quantitative relaxometry and diffusion tensor imaging (DTI) with support vector machines (SVM) aiming to improve TLE detection. The main contribution of this work is two-fold: on one hand, the feature selection process, principal component analysis (PCA) transformations of the feature space, and SVM parameterization are analyzed as factors constituting a classification …

Image Registration Of Ex-Vivo Mri To Sparsely Sectioned Histology Of Hippocampal And Neocortical Temporal Lobe Specimens., Maged Goubran, Cathie Crukley, Sandrine De Ribaupierre, Terence M Peters, Ali R Khan

Robarts Imaging Publications

Intractable or drug-resistant epilepsy occurs in up to 30% of epilepsy patients, with many of these patients undergoing surgical excision of the affected brain region to achieve seizure control. Recent magnetic resonance imaging (MRI) sequences and analysis techniques have the potential to detect abnormalities not identified with diagnostic MRI protocols. Prospective studies involving pre-operative imaging and collection of surgically-resected tissue provide a unique opportunity for verification and tuning of these image analysis techniques, since direct comparison can be made against histopathology, and can lead to better prediction of surgical outcomes and potentially less invasive procedures. To carry out MRI and …

Biomarkers For Brain Disorders Electrochemically Detected By Broderick Probe Microelectrodes/Biosensors, Waqas Saleem, Patricia A. Broderick

Publications and Research

Here, we present results from two independent studies carried out using Neuromolecular Imaging (NMI) with miniature BRODERICK PROBE® biosensors. In the first study, we imaged neurotransmitters and neurochemicals in human epilepsy patients intraoperatively during early and late neurodegeneration. In the second study, we imaged neurotransmitters and neurochemicals in an experimental murine model using animals with and without neurodegeneration caused by Parkinson’s disease (PD). We compared our results derived from animals with lesioned group (PD) with non-lesioned group (non-PD), using the same in vivo NMI paradigm. NMI biotechnology enabled neurotransmitters, neuropeptides and neurochemical imaging of dopamine (DA), serotonin (5-HT), homovanillic acid …

Computational Model Of Neuron-Astrocyte Interputational Model Of Neuron-Astrocyte Interactions During Focal Seizure Generationactions During Focal Seizure Generation, Davide Reato, Mario Cammarota, Lucas C. Parra, Giorgio Carmignoto

Publications and Research

Empirical research in the last decade revealed that astrocytes can respond to neurotransmitters with Ca2+ elevations and generate feedback signals to neurons which modulate synaptic transmission and neuronal excitability. This discovery changed our basic understanding of brain function and provided new perspectives for how astrocytes can participate not only to information processing, but also to the genesis of brain disorders, such as epilepsy. Epilepsy is a neurological disorder characterized by recurrent seizures that can arise focally at restricted areas and propagate throughout the brain. Studies in brain slice models suggest that astrocytes contribute to epileptiform activity by increasing neuronal excitability …

Methods For Detecting High-Frequency Oscillations In Ongoing Brain Signals: Application To The Determination Of Epileptic Seizure Onset Zones, Chiran Dilip Doshi

Master's Theses (2009 -)

Epilepsy is a neurological disorder with varied expression. Patients with focal onset seizures that are resistant to medications can benefit from ablative surgery. However, localization of the seizure onset zone (SOZ) and characterization of propagation to secondary areas can be challenging. The present study aimed at developing the appropriate signal processing methodology to detect bursts of interictal high-frequency oscillations (HFOs), as a possible signature of the SOZ, in patients with drug-resistant partial epilepsy. Additionally, invasive interictal and ictal intracranial electroencephalography (iEEG) data and non-invasive electromagnetic source imaging with magnetoencephalography (MEG) data from three subjects were analyzed. We developed a novel …

Fusion And Visualization Of Intraoperative Cortical Images With Preoperative Models For Epilepsy Surgical Planning And Guidance., A Wang, S M Mirsattari, A G Parrent, T M Peters

Robarts Imaging Publications

OBJECTIVE: During epilepsy surgery it is important for the surgeon to correlate the preoperative cortical morphology (from preoperative images) with the intraoperative environment. Augmented Reality (AR) provides a solution for combining the real environment with virtual models. However, AR usually requires the use of specialized displays, and its effectiveness in the surgery still needs to be evaluated. The objective of this research was to develop an alternative approach to provide enhanced visualization by fusing a direct (photographic) view of the surgical field with the 3D patient model during image guided epilepsy surgery.

MATERIALS AND METHODS: We correlated the preoperative plan …