Medicine (Austin & Northern Health) - Research Publications

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    Learn how to interpret and use intracranial EEG findings
    Frauscher, B ; Mansilla, D ; Abdallah, C ; Astner-Rohracher, A ; Beniczky, S ; Brazdil, M ; Gnatkovsky, V ; Jacobs, J ; Kalamangalam, G ; Perucca, P ; Ryvlin, P ; Schuele, S ; Tao, J ; Wang, Y ; Zijlmans, M ; McGonigal, A (WILEY, 2024-02)
    Epilepsy surgery is the therapy of choice for many patients with drug-resistant focal epilepsy. Recognizing and describing ictal and interictal patterns with intracranial electroencephalography (EEG) recordings is important in order to most efficiently leverage advantages of this technique to accurately delineate the seizure-onset zone before undergoing surgery. In this seminar in epileptology, we address learning objective "1.4.11 Recognize and describe ictal and interictal patterns with intracranial recordings" of the International League against Epilepsy curriculum for epileptologists. We will review principal considerations of the implantation planning, summarize the literature for the most relevant ictal and interictal EEG patterns within and beyond the Berger frequency spectrum, review invasive stimulation for seizure and functional mapping, discuss caveats in the interpretation of intracranial EEG findings, provide an overview on special considerations in children and in subdural grids/strips, and review available quantitative/signal analysis approaches. To be as practically oriented as possible, we will provide a mini atlas of the most frequent EEG patterns, highlight pearls for its not infrequently challenging interpretation, and conclude with two illustrative case examples. This article shall serve as a useful learning resource for trainees in clinical neurophysiology/epileptology by providing a basic understanding on the concepts of invasive intracranial EEG.
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    Door-to-diuretic time and mortality in patients with acute heart failure: A systematic review and meta-analysis.
    Sampaio Rodrigues, T ; Garcia Quarto, LJ ; Nogueira, SC ; Theuerle, JD ; Farouque, O ; Burrell, LM ; Koshy, AN (Elsevier BV, 2024-03)
    Early decongestion therapy with intravenous diuretics may be associated with improved outcomes in acute heart failure (AHF), however data is conflicting. This meta-analysis sought to evaluate the impact of door-to-IV diuretic (D2D) time on mortality in patients with AHF. Pooled estimates from observational studies comprising 28,124 patients, early IV diuresis (reference time 30-105 minutes) was associated with a 23% reduction in 30-day mortality in AHF (OR 0.77; 95% CI 0.64-0.93), despite no significant in-hospital death reduction (OR 0.84; 95% CI 0.57-1.24).
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    Prevalence of Arm Weakness, Pre-Stroke Outcomes and Other Post-Stroke Impairments Using Routinely Collected Clinical Data on an Acute Stroke Unit
    Dalton, EJ ; Jamwal, R ; Augoustakis, L ; Hill, E ; Johns, H ; Thijs, V ; Hayward, KS (SAGE PUBLICATIONS INC, 2024-02)
    INTRODUCTION: The prevalence of upper limb motor weakness early post-stroke may be changing, which can have clinical and research implications. Our primary aim was to describe the prevalence of upper limb motor weakness early post-stroke, with a secondary aim to contextualize this prevalence by describing pre-stroke outcomes, other post-stroke impairments, functional activities, and discharge destination. METHODS: This cross-sectional observational study extracted clinical data from confirmed stroke patients admitted to a metropolitan stroke unit over 15-months. The primary upper limb weakness measure was Shoulder Abduction and Finger Extension (SAFE) score. Demographics (eg, age), clinical characteristics (eg, stroke severity), pre-stroke outcomes (eg, clinical frailty), other post-stroke impairments (eg, command following), functional activities (eg, ambulation), and discharge destination were also extracted. RESULTS: A total of 463 participants had a confirmed stroke and SAFE score. One-third of patients received ≥1 acute medical intervention(s). Nearly one-quarter of patients were classified as frail pre-stroke. Upper limb weakness (SAFE≤8) was present in 35% [95% CI: 30%-39%] at a median of 1-day post-stroke, with 22% presenting with mild-moderate weakness (SAFE5-8). The most common other impairments were upper limb coordination (46%), delayed recall (41%), and upper limb sensation (26%). After a median 3-day acute stroke stay, 52% of the sample were discharged home. CONCLUSION: Upper limb weakness was present in just over a third (35%) of the sample early post-stroke. Data on pre-stroke outcomes and the prevalence of other post-stroke impairments highlights the complexity and heterogeneity of stroke recovery. Further research is required to tease out meaningful recovery phenotypes and their implications.
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    Expanding the phenotype of Kleefstra syndrome: speech, language and cognition in 103 individuals
    Morison, LD ; Kennis, MGP ; Rots, D ; Bouman, A ; Kummeling, J ; Palmer, E ; Vogel, AP ; Liegeois, F ; Brignell, A ; Srivastava, S ; Frazier, Z ; Milnes, D ; Goel, H ; Amor, DJ ; Scheffer, IE ; Kleefstra, T ; Morgan, AT (BMJ PUBLISHING GROUP, 2024-01-30)
    OBJECTIVES: Speech and language impairments are core features of the neurodevelopmental genetic condition Kleefstra syndrome. Communication has not been systematically examined to guide intervention recommendations. We define the speech, language and cognitive phenotypic spectrum in a large cohort of individuals with Kleefstra syndrome. METHOD: 103 individuals with Kleefstra syndrome (40 males, median age 9.5 years, range 1-43 years) with pathogenic variants (52 9q34.3 deletions, 50 intragenic variants, 1 balanced translocation) were included. Speech, language and non-verbal communication were assessed. Cognitive, health and neurodevelopmental data were obtained. RESULTS: The cognitive spectrum ranged from average intelligence (12/79, 15%) to severe intellectual disability (12/79, 15%). Language ability also ranged from average intelligence (10/90, 11%) to severe intellectual disability (53/90, 59%). Speech disorders occurred in 48/49 (98%) verbal individuals and even occurred alongside average language and cognition. Developmental regression occurred in 11/80 (14%) individuals across motor, language and psychosocial domains. Communication aids, such as sign and speech-generating devices, were crucial for 61/103 (59%) individuals including those who were minimally verbal, had a speech disorder or following regression. CONCLUSIONS: The speech, language and cognitive profile of Kleefstra syndrome is broad, ranging from severe impairment to average ability. Genotype and age do not explain the phenotypic variability. Early access to communication aids may improve communication and quality of life.
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    Stuttering associated with a pathogenic variant in the chaperone protein cyclophilin 40
    Morgan, AT ; Scerri, TS ; Vogel, AP ; Reid, CA ; Quach, M ; Jackson, VE ; McKenzie, C ; Burrows, EL ; Bennett, MF ; Turner, SJ ; Reilly, S ; Horton, SE ; Block, S ; Kefalianos, E ; Frigerio-Domingues, C ; Sainz, E ; Rigbye, KA ; Featherby, TJ ; Richards, KL ; Kueh, A ; Herold, MJ ; Corbett, MA ; Gecz, J ; Helbig, I ; Thompson-Lake, DGY ; Liegeois, FJ ; Morell, RJ ; Hung, A ; Drayna, D ; Scheffer, IE ; Wright, DK ; Bahlo, M ; Hildebrand, MS (OXFORD UNIV PRESS, 2023-12-01)
    Stuttering is a common speech disorder that interrupts speech fluency and tends to cluster in families. Typically, stuttering is characterized by speech sounds, words or syllables which may be repeated or prolonged and speech that may be further interrupted by hesitations or 'blocks'. Rare variants in a small number of genes encoding lysosomal pathway proteins have been linked to stuttering. We studied a large four-generation family in which persistent stuttering was inherited in an autosomal dominant manner with disruption of the cortico-basal-ganglia-thalamo-cortical network found on imaging. Exome sequencing of three affected family members revealed the PPID c.808C>T (p.Pro270Ser) variant that segregated with stuttering in the family. We generated a Ppid p.Pro270Ser knock-in mouse model and performed ex vivo imaging to assess for brain changes. Diffusion-weighted MRI in the mouse revealed significant microstructural changes in the left corticospinal tract, as previously implicated in stuttering. Quantitative susceptibility mapping also detected changes in cortico-striatal-thalamo-cortical loop tissue composition, consistent with findings in affected family members. This is the first report to implicate a chaperone protein in the pathogenesis of stuttering. The humanized Ppid murine model recapitulates network findings observed in affected family members.
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    Diagnostic Utility of Genome-wide DNA Methylation Analysis in Genetically Unsolved Developmental and Epileptic Encephalopathies and Refinement of a CHD2 Episignature.
    LaFlamme, CW ; Rastin, C ; Sengupta, S ; Pennington, HE ; Russ-Hall, SJ ; Schneider, AL ; Bonkowski, ES ; Almanza Fuerte, EP ; Galey, M ; Goffena, J ; Gibson, SB ; Allan, TJ ; Nyaga, DM ; Lieffering, N ; Hebbar, M ; Walker, EV ; Darnell, D ; Olsen, SR ; Kolekar, P ; Djekidel, N ; Rosikiewicz, W ; McConkey, H ; Kerkhof, J ; Levy, MA ; Relator, R ; Lev, D ; Lerman-Sagie, T ; Park, KL ; Alders, M ; Cappuccio, G ; Chatron, N ; Demain, L ; Genevieve, D ; Lesca, G ; Roscioli, T ; Sanlaville, D ; Tedder, ML ; Hubshman, MW ; Ketkar, S ; Dai, H ; Worley, KC ; Rosenfeld, JA ; Chao, H-T ; Undiagnosed Diseases Network, ; Neale, G ; Carvill, GL ; University of Washington Center for Rare Disease Research, ; Wang, Z ; Berkovic, SF ; Sadleir, LG ; Miller, DE ; Scheffer, IE ; Sadikovic, B ; Mefford, HC (Cold Spring Harbor Laboratory, 2023-10-12)
    Sequence-based genetic testing currently identifies causative genetic variants in ∼50% of individuals with developmental and epileptic encephalopathies (DEEs). Aberrant changes in DNA methylation are implicated in various neurodevelopmental disorders but remain unstudied in DEEs. Rare epigenetic variations ("epivariants") can drive disease by modulating gene expression at single loci, whereas genome-wide DNA methylation changes can result in distinct "episignature" biomarkers for monogenic disorders in a growing number of rare diseases. Here, we interrogate the diagnostic utility of genome-wide DNA methylation array analysis on peripheral blood samples from 516 individuals with genetically unsolved DEEs who had previously undergone extensive genetic testing. We identified rare differentially methylated regions (DMRs) and explanatory episignatures to discover causative and candidate genetic etiologies in 10 individuals. We then used long-read sequencing to identify DNA variants underlying rare DMRs, including one balanced translocation, three CG-rich repeat expansions, and two copy number variants. We also identify pathogenic sequence variants associated with episignatures; some had been missed by previous exome sequencing. Although most DEE genes lack known episignatures, the increase in diagnostic yield for DNA methylation analysis in DEEs is comparable to the added yield of genome sequencing. Finally, we refine an episignature for CHD2 using an 850K methylation array which was further refined at higher CpG resolution using bisulfite sequencing to investigate potential insights into CHD2 pathophysiology. Our study demonstrates the diagnostic yield of genome-wide DNA methylation analysis to identify causal and candidate genetic causes as ∼2% (10/516) for unsolved DEE cases.
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    Atherosclerosis on CT coronary angiography and the risk of long-term cardiovascular events after liver transplantation.
    Sampaio Rodrigues, T ; Koshy, AN ; Gow, PJ ; Weinberg, L ; Cailes, B ; Testro, A ; Smith, G ; Lim, HS ; Teh, AW ; Lim, RP ; Farouque, O (Ovid Technologies (Wolters Kluwer Health), 2024-02-01)
    Computed tomography coronary angiography (CTCA) is increasingly utilized for preoperative risk stratification before liver transplantation (LT). We sought to assess the predictors of advanced atherosclerosis on CTCA using the recently developed Coronary Artery Disease-Reporting and Data System (CAD-RADS) score and its impact on the prediction of long-term major adverse cardiovascular events (MACE) following LT. We conducted a retrospective cohort study of consecutive patients who underwent CTCA for LT work-up between 2011 and 2018. Advanced atherosclerosis was defined as coronary artery calcium scores > 400 or CAD-RADS score ≥ 3 (≥50% coronary artery stenosis). MACE was defined as myocardial infarction, heart failure, stroke, or resuscitated cardiac arrest. Overall, 229 patients underwent CTCA (mean age 66 ± 5 y, 82% male). Of these, 157 (68.5%) proceeded with LT. The leading etiology of cirrhosis was hepatitis (47%), and 53% of patients had diabetes before transplant. On adjusted analysis, male sex (OR 4.6, 95% CI 1.5-13.8, p = 0.006), diabetes (OR 2.2, 95% CI 1.2-4.2, p = 0.01) and dyslipidemia (OR 3.1, 95% CI 1.3-6.9, p = 0.005) were predictors of advanced atherosclerosis on CTCA. Thirty-two patients (20%) experienced MACE. At a median follow-up of 4 years, CAD-RADS ≥ 3, but not coronary artery calcium scores, was associated with a heightened risk of MACE (HR 5.8, 95% CI 1.6-20.6, p = 0.006). Based on CTCA results, 71 patients (31%) commenced statin therapy which was associated with a lower risk of all-cause mortality (HR 0.48, 95% CI 0.24-0.97, p = 0.04). The standardized CAD-RADS classification on CTCA predicted the occurrence of cardiovascular outcomes following LT, with a potential to increase the utilization of preventive cardiovascular therapies.
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    The teratogenesis risk associated with antiseizure medication duotherapy in women with epilepsy.
    Vajda, FJE ; O'Brien, TJ ; Graham, JE ; Hitchcock, AA ; Perucca, P ; Lander, CM ; Eadie, MJ (Elsevier BV, 2024-02)
    PURPOSE: To investigate rates of occurrence of pregnancies associated with a foetal malformation (FM pregnancy rates) following simultaneous intrauterine exposure to two antiseizure medications in 524 pregnancies in women with epilepsy from the Australian Pregnancy Register who were treated simultaneously with various combinations and dosages of two antiseizure medications (duotherapy). RESULTS: FM pregnancy rates tended to be higher in those exposed simultaneously to two antiseizure medications, each of which was a statistically significant teratogen (valproate, topiramate, or carbamazepine), than when there was exposure to only one such teratogen. When there was exposure to only one such teratogen together with clonazepam or levetiracetam, for neither of which there was statistically significant evidence of heightened teratogenicity, the FM pregnancy rates also tended to be higher, but less so. When lamotrigine was the other component of the duotherapy with an established teratogen, FM pregnancy rates tended to be lower than that for the teratogen used as monotherapy. CONCLUSION: Leaving aside issues in relation to seizure control, our data suggest that it would be best to avoid using established teratogenic antiseizure medications (carbamazepine, valproate and topiramate) in combination with each other due to the increased FM risks. When combining an established teratogenic medication with a less teratogenic one, i.e. lamotrigine, levetiracetam or clonazepam, lamotrigine appears to be the safer option.
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    Perisylvian and Hippocampal Anomalies in Individuals With Pathogenic GRIN2A Variants
    Thompson-Lake, DGY ; Liegeois, FJ ; Braden, RO ; Jackson, GD ; Turner, SJ ; Morison, L ; Hildebrand, M ; Scheffer, IE ; Morgan, AT (Wolters Kluwer, 2024-04)
    Background and Objectives: Pathogenic variants in GRIN2A are associated with a spectrum of epilepsy-aphasia syndromes (EASs). Seizures as well as speech and language disorders occur frequently but vary widely in severity, both between individuals and across the life span. The link between this phenotypic spectrum and brain characteristics is unknown. Specifically, altered brain networks at the root of speech and language deficits remain to be identified. Patients with pathogenic variants in GRIN2A offer an opportunity to interrogate the impact of glutamate receptor dysfunction on brain development. Methods: We characterized brain anomalies in individuals with pathogenic GRIN2A variants and EASs, hypothesizing alterations in perisylvian speech-language regions and the striatum. We compared structural MRI data from 10 individuals (3 children and 7 adults, 3 female) with pathogenic GRIN2A variants with data from age-matched controls (N = 51 and N = 203 in a secondary analysis). We examined cortical thickness and volume in 4 a priori hypothesized speech and language regions (inferior frontal, precentral, supramarginal, and superior temporal) and across the whole brain. Subcortical structures (hippocampus, basal ganglia, thalamus) and the corpus callosum were also compared. Results: Individuals with pathogenic GRIN2A variants showed increased thickness and volume in the posterior part of Broca's area (inferior frontal gyrus, pars opercularis). For thickness, the effects were bilateral but more pronounced in the left (large effect size, η2 = 0.37) than the right (η2 = 0.12) hemisphere. Both volume and thickness were also higher in the bilateral superior temporal region while the supramarginal region showed increased thickness only. Whole-brain analyses confirmed left-sided thickness increases in Broca's area, with additional increases in the occipital and superior frontal cortices bilaterally. Hippocampal volume was reduced in the left hemisphere. There were no age-dependent effects or corpus callosum group differences. Discussion: Anomalies in perisylvian regions, with largest differences in Broca's area, suggest an altered development of classical speech-language networks in GRIN2A-related EAS. Left hippocampal reduction suggests a role for this structure in early speech and language development and is consistent with GRIN2A gene expression in that region. Overall, elucidating the neural correlates of EAS provides insights into the impact of GRIN2A dysfunction, opening avenues for targeted intervention in developmental syndromes with compromised speech-language development.
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    Plasma neurofilament light in behavioural variant frontotemporal dementia compared to mood and psychotic disorders
    Eratne, D ; Kang, M ; Malpas, C ; Simpson-Yap, S ; Lewis, C ; Dang, C ; Grewal, J ; Coe, A ; Dobson, H ; Keem, M ; Chiu, W-H ; Kalincik, T ; Ooi, S ; Darby, D ; Brodtmann, A ; Hansson, O ; Janelidze, S ; Blennow, K ; Zetterberg, H ; Walker, A ; Dean, O ; Berk, M ; Wannan, C ; Pantelis, C ; Loi, SM ; Walterfang, M ; Berkovic, SF ; Santillo, AF ; Velakoulis, D (SAGE PUBLICATIONS LTD, 2024-01)
    OBJECTIVE: Blood biomarkers of neuronal injury such as neurofilament light (NfL) show promise to improve diagnosis of neurodegenerative disorders and distinguish neurodegenerative from primary psychiatric disorders (PPD). This study investigated the diagnostic utility of plasma NfL to differentiate behavioural variant frontotemporal dementia (bvFTD, a neurodegenerative disorder commonly misdiagnosed initially as PPD), from PPD, and performance of large normative/reference data sets and models. METHODS: Plasma NfL was analysed in major depressive disorder (MDD, n = 42), bipolar affective disorder (BPAD, n = 121), treatment-resistant schizophrenia (TRS, n = 82), bvFTD (n = 22), and compared to the reference cohort (Control Group 2, n = 1926, using GAMLSS modelling), and age-matched controls (Control Group 1, n = 96, using general linear models). RESULTS: Large differences were seen between bvFTD (mean NfL 34.9 pg/mL) and all PPDs and controls (all < 11 pg/mL). NfL distinguished bvFTD from PPD with high accuracy, sensitivity (86%), and specificity (88%). GAMLSS models using reference Control Group 2 facilitated precision interpretation of individual levels, while performing equally to or outperforming models using local controls. Slightly higher NfL levels were found in BPAD, compared to controls and TRS. CONCLUSIONS: This study adds further evidence on the diagnostic utility of NfL to distinguish bvFTD from PPD of high clinical relevance to a bvFTD differential diagnosis, and includes the largest cohort of BPAD to date. Using large reference cohorts, GAMLSS modelling and the interactive Internet-based application we developed, may have important implications for future research and clinical translation. Studies are underway investigating utility of plasma NfL in diverse neurodegenerative and primary psychiatric conditions in real-world clinical settings.