Publications by authors named "Matt Wheatley"

Objectives: Studies have suggested intrapulmonary shunts may contribute to hypoxemia in COVID-19 acute respiratory distress syndrome (ARDS) with worse associated outcomes. We evaluated the presence of right-to-left (R-L) shunts in COVID-19 and non-COVID ARDS patients using a comprehensive hypoxemia workup for shunt etiology and associations with mortality.

Design: Prospective, observational cohort study.

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Electroencephalograms are commonly ordered by acute care doctors but not always understood. Other reviews have covered when and how to perform electroencephalograms. This primer has a different, unique, and complementary goal.

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Background: Medically-refractory trigeminal neuralgia (TN) can be treated successfully with operative intervention, but a significant proportion of patients are non-responders despite undergoing technically successful surgery. The thalamus is a key component of the trigeminal sensory pathway involved in transmitting facial pain, but the role of the thalamus in TN, and its influence on durability of pain relief after TN surgery, are relatively understudied. We aimed to test the hypothesis that variations in thalamic structure and metabolism are related to surgical non-response in TN.

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Objective: Neuropathological studies indicate that hippocampal sclerosis (HS) consists of three subtypes (ILAE types 1-3 HS). However, HS subtypes currently can only be diagnosed by pathological analysis of hippocampal tissue resected during epilepsy surgery or at autopsy. In vivo diagnosis of HS subtypes holds potential to improve our understanding of these variants in the ipsilateral as well as contralateral hippocampus.

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Objective: Hippocampal sclerosis (HS) is the most common pathology and best predictor of surgical outcome for medically refractory patients with temporal lobe epilepsy (TLE). Current clinical MRI methods can detect HS, but subfield pathology is poorly characterized, limiting accurate prediction of seizure-free outcomes after surgery. Diffusion tensor imaging (DTI) can probe regional microstructural changes associated with focal hippocampal pathology, but is typically limited by low-resolution whole-brain acquisitions.

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Background: Many medically-refractory trigeminal neuralgia patients are non-responders to surgical treatment. Few studies have explored how trigeminal nerve characteristics relate to surgical outcome, and none have investigated the relationship between subcortical brain structure and treatment outcomes.

Methods: We retrospectively studied trigeminal neuralgia patients undergoing surgical treatment with microvascular decompression.

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Objective: Diffusion tensor imaging (DTI) tractography is commonly used in neurosurgical practice but is largely limited to the preoperative setting. This is due primarily to image degradation caused by susceptibility artifact when conventional single-shot (SS) echo-planar imaging (EPI) DTI (SS-DTI) is acquired for open cranial, surgical position intraoperative DTI (iDTI). Readout-segmented (RS) EPI DTI (RS-DTI) has been reported to reduce such artifact but has not yet been evaluated in the intraoperative MRI (iMRI) environment.

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OBJECTIVE The aim of this study was to investigate long-term seizure outcome, rate of reoperation, and postoperative neuropsychological performance following selective amygdalohippocampectomy (SelAH) or anterior temporal lobectomy (ATL) in pediatric patients with medically refractory temporal lobe epilepsy (TLE). METHODS The authors performed a retrospective review of cases of medically refractory pediatric TLE treated initially with either SelAH or ATL. Standardized pre- and postoperative evaluation included seizure charting, surface and long-term video-electroencephalography, 1.

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Objectives: 1) Characterize the evolution of microstructural changes in the contralateral, non-operated hippocampus-using longitudinal diffusion tensor imaging (DTI)-following surgery for temporal lobe epilepsy (TLE). 2) Characterize the downstream extra-hippocampal volumetric changes of the fornix and mammillary bodies after TLE surgery. 3) Examine the relationship between these measures and seizure/cognitive outcome.

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Immune mechanisms have been increasingly recognized in the pathogenesis of hippocampal sclerosis (HS), but infiltration of cytotoxic T-cells and its pathological significance in patients with HS has not been explored. We examined 30 cases of surgically resected hippocampi, including 16 International League Against Epilepsy (ILAE) type 1, 9 ILAE type 2, 1 ILAE type 3 HS, and 4 ILAE No-HS, as well as 6 autopsy No-HS hippocampi. The HS hippocampi showed sparse to scattered CD8-positive T-cells, rare CD4-positive T-cells, and a modest increase in CD68-positive microglia/macrophages, which were significantly more numerous than those in the No-HS controls.

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Objective: Determine the extent and time course of volumetric changes in the contralateral hippocampus following surgery for medically refractory temporal lobe epilepsy (TLE).

Methods: Serial T1-weighted MRI brain scans were obtained in 26 TLE patients pre- and post-temporal lobe epilepsy surgery as well as in 12 control subjects of similar age. Patients underwent either anterior temporal lobectomy (ATL) or selective amygdalohippocampectomy (SAH).

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Observation Services (OS) was founded by emergency physicians in an attempt to manage "boarding" issues faced by emergency departments throughout the United States. As a result, OS have proven to be an effective strategy in reducing costs and decreasing lengths of stay while improving patient outcomes. When OS are appropriately leveraged for maximum efficiency, patients presenting to emergency departments with common disease processes can be effectively treated in a timely manner.

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Aim: This case report provides insight into the function of the anterior prefrontal cortex (aPFC), specifically Brodmann Area 10 (BA10), and its interconnectivity.

Method: We present a 10-year-old patient with lesional epilepsy and ictal onset, localised to BA10 in the aPFC.

Results: Thirty-four seizures were recorded.

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Background: Rasmussen's encephalitis (RE) is an inflammatory encephalopathy of unknown cause defined by seizures with progressive neurological disabilities. Herein, the pathogenesis of RE was investigated focusing on inflammasome activation in the brain.

Methods: Patients with RE at the University of Alberta, Edmonton, AB, Canada, were identified and analyzed by neuroimaging, neuropsychological, molecular, and pathological tools.

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Numerous animal studies have shown the applicability of diffusion tensor imaging (DTI) to track Wallerian degeneration that occurs after injury to the neural fiber. Non-invasive biomarkers that may differentiate the early axonal breakdown and later myelin degradation have been attributed to either reduced parallel and elevated perpendicular diffusivity, respectively. While several human DTI studies have shown this potential at subacute and chronic time points, the diffusion changes that occur within the first week are unknown.

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The brain is assumed to be a sterile organ in the absence of disease although the impact of immune disruption is uncertain in terms of brain microbial diversity or quantity. To investigate microbial diversity and quantity in the brain, the profile of infectious agents was examined in pathologically normal and abnormal brains from persons with HIV/AIDS [HIV] (n = 12), other disease controls [ODC] (n = 14) and in cerebral surgical resections for epilepsy [SURG] (n = 6). Deep sequencing of cerebral white matter-derived RNA from the HIV (n = 4) and ODC (n = 4) patients and SURG (n = 2) groups revealed bacterially-encoded 16 s RNA sequences in all brain specimens with α-proteobacteria representing over 70% of bacterial sequences while the other 30% of bacterial classes varied widely.

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Background: The surgical removal of the epileptogenic zone in medically intractable seizures depends on accurate localization to minimize the neurological sequelae and prevent future seizures. To date, few studies have demonstrated the use of depth electrodes in a pediatric epilepsy population. Here, we report our study of pediatric epilepsy patients at our epilepsy center who were successfully operated for medically intractable seizures following the use of intracranial depth electrodes.

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Background: The glycoprotein, Syncytin-1, is encoded by a human endogenous retrovirus (HERV)-W env gene and is capable of inducing neuroinflammation. The specific allele(s) responsible for Syncytin-1 expression in the brain is uncertain. Herein, HERV-W env diversity together with Syncytin-1 abundance and host immune gene profiles were examined in the nervous system using a multiplatform approach.

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Tuberous sclerosis complex is an autosomal-dominant genetic disorder characterized by hamartomatous growth in various organs. Patients who have this disorder exhibit a high rate of epilepsy and cognitive problems. We investigated number of tubers, location, seizure types, and cognitive outcome, and we analyzed the relationships among them in our tuberous sclerosis patients in the Comprehensive Epilepsy Program at the University of Alberta.

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Epilepsy surgery is known to help children with intractable seizures. The effect of epilepsy surgery itself on cognition in childhood is less well studied. We report our experience at the University of Alberta Hospital on the effects of epilepsy surgery on cognition.

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While diffusion tensor imaging (DTI) has been extensively used to infer micro-structural characteristics of cerebral white matter in human conditions, correlations between human in vivo DTI and histology have not been performed. Temporal lobe epilepsy (TLE) patients with mesial temporal sclerosis (MTS) have abnormal DTI parameters of the fimbria-fornix (relative to TLE patients without MTS) which are presumed to represent differences in axonal/myelin integrity. Medically intractable TLE patients who undergo temporal lobe resection including the fimbria-fornix provide a unique opportunity to study the anatomical correlates of water diffusion abnormalities in freshly excised tissue.

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The most common surgical procedure for the mesial temporal lobe is the standard anterior temporal resection or what is commonly called the anterior temporal lobectomy. There are, however, a number of other more selective procedures for removal of the mesial temporal lobe structures (amygdala, hippocampus, and parahippocampal gyrus) that spare much of the lateral temporal neocortex. Included in these procedures collectively referred to as selective amygdalohippocampectomy are the transsylvian, subtemporal, and transcortical (trans-middle temporal gyrus) selective amygdalohippocampectomy.

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In children with medically intractable seizures, epilepsy surgery is now a widely accepted option. Successful discontinuation of antiepileptic drugs after epilepsy surgery has been reported in adults, but rarely in children. Surgical outcome and need for antiepileptic drugs after temporal and extratemporal lobe resection were retrospectively reviewed for 80 pediatric patients from the Comprehensive Epilepsy Program at the University of Alberta.

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Purpose: Bilateral white matter diffusion tensor imaging (DTI) abnormalities have been reported in patients with temporal lobe epilepsy (TLE) and unilateral mesial temporal sclerosis (MTS), but it is unknown whether these are functional or structural changes. We performed a longitudinal study in patients with unilateral MTS who were seizure-free for 1 year after surgery to determine whether the observed presurgical white matter diffusion abnormalities were reversible.

Methods: Eight TLE patients with unilateral MTS who were seizure-free after anterior temporal resection and 22 healthy subjects were recruited.

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