Publications by authors named "Peter Ljubenkov"

Article Synopsis
  • Diminished activity in the parasympathetic nervous system, particularly baseline respiratory sinus arrhythmia, is linked to empathy issues in individuals with frontotemporal dementia (FTD), especially those with left frontoinsula dysfunction.
  • In a study involving 102 participants, including asymptomatic and symptomatic carriers of the C9orf72 gene mutation, researchers found that those with symptomatic FTD exhibited significantly lower respiratory sinus arrhythmia compared to other groups, indicating disrupted parasympathetic activity.
  • Results showed a correlation between lower respiratory sinus arrhythmia and greater behavioral symptom severity as well as reduced empathic concern, suggesting that parasympathetic deficits might play a role in the progression of FTD.
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Article Synopsis
  • The study aimed to identify fluid biomarkers in cerebrospinal fluid (CSF) for progressive supranuclear palsy (PSP) to aid in developing new therapies, utilizing advanced proteomic analysis methods.
  • Researchers analyzed a total of 136 participants across various groups, comparing individuals with PSP (Richardson syndrome) against healthy controls, using sophisticated platforms to assess the presence of specific proteins (SOMAmers) in CSF.
  • Findings revealed that many SOMAmers were differentially expressed in PSP patients, indicating potential biomarkers, with three significant biological pathways linked to disease progression identified, including synaptic functions and cytokine interactions.
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Objectives: To evaluate the effect of Alzheimer's disease (AD) -related biomarker change on clinical features, brain atrophy and functional connectivity of patients with corticobasal syndrome (CBS) and progressive supranuclear palsy (PSP).

Methods: Data from patients with a clinical diagnosis of CBS, PSP, and AD and healthy controls were obtained from the 4-R-Tauopathy Neuroimaging Initiative 1 and 2, the Alzheimer's Disease Neuroimaging Initiative, and a local cohort from the Toronto Western Hospital. Patients with CBS and PSP were divided into AD-positive (CBS/PSP-AD) and AD-negative (CBS/PSP-noAD) groups based on fluid biomarkers and amyloid PET scans.

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Article Synopsis
  • Lewy body disease (LBD) is involved in various neurodegenerative syndromes, and the αSyn-SAA assay shows excellent sensitivity and specificity for diagnosing cortical LBD cases.
  • However, the assay has lower sensitivity in amygdala-predominant and brainstem-predominant LBD cases, though positive results may indicate early disease progression.
  • Overall, the αSyn-SAA assay offers precise diagnosis of LBD and may help identify co-pathologies, which could influence treatment outcomes and aid in clinical trials.
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Tau PET has enabled the visualization of paired helical filaments of 3 or 4 C-terminal repeat tau in Alzheimer disease (AD), but its ability to detect aggregated tau in frontotemporal lobar degeneration (FTLD) spectrum disorders is uncertain. We investigated 2-(2-([F]fluoro)pyridin-4-yl)-9-pyrrolo[2,3-b:4,5c']dipyridine ([F]PI-2620), a newer tracer with ex vivo evidence for binding to FTLD tau, in a convenience sample of patients with suspected FTLD and AD using a static acquisition protocol and parametric SUV ratio (SUVr) images. We analyzed [F]PI-2620 PET data from 65 patients with clinical diagnoses associated with AD or FTLD neuropathology; most (60/65) also had amyloid-β (Aβ) PET.

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Importance: Plasma phosphorylated tau217 (p-tau217), a biomarker of Alzheimer disease (AD), is of special interest in corticobasal syndrome (CBS) because autopsy studies have revealed AD is the driving neuropathology in up to 40% of cases. This differentiates CBS from other 4-repeat tauopathy (4RT)-associated syndromes, such as progressive supranuclear palsy Richardson syndrome (PSP-RS) and nonfluent primary progressive aphasia (nfvPPA), where underlying frontotemporal lobar degeneration (FTLD) is typically the primary neuropathology.

Objective: To validate plasma p-tau217 against positron emission tomography (PET) in 4RT-associated syndromes, especially CBS.

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Background: Measuring systemic inflammatory markers may improve clinical prognosis and help identify targetable pathways for treatment in patients with autosomal dominant forms of frontotemporal lobar degeneration (FTLD).

Methods: We measured plasma concentrations of IL-6, TNFα and YKL-40 in pathogenic variant carriers () and non-carrier family members enrolled in the ARTFL-LEFFTDS Longitudinal Frontotemporal Lobar Degeneration consortium. We evaluated associations between baseline plasma inflammation and rate of clinical and neuroimaging changes (linear mixed effects models with standardised (z) outcomes).

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Unlike familial Alzheimer's disease, we have been unable to accurately predict symptom onset in presymptomatic familial frontotemporal dementia (f-FTD) mutation carriers, which is a major hurdle to designing disease prevention trials. We developed multimodal models for f-FTD disease progression and estimated clinical trial sample sizes in C9orf72, GRN and MAPT mutation carriers. Models included longitudinal clinical and neuropsychological scores, regional brain volumes and plasma neurofilament light chain (NfL) in 796 carriers and 412 noncarrier controls.

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-related leukoencephalopathy is an autosomal dominant neurodegenerative disease caused by mutations in the tyrosine kinase domain of the colony stimulating factor 1 receptor (CSF1R). Several studies have found that hematogenic stem cell transplantation is an effective disease modifying therapy however the literature regarding prodromal and early symptoms -related leukoencephalopathy is limited. We describe a 63-year-old patient with 4 years of repetitive scratching and skin picking behavior followed by 10 years of progressive behavioral, cognitive, and motor decline in a pattern suggesting behavioral variant of frontotemporal dementia.

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Background And Objectives: Changes in social behavior are common symptoms of frontotemporal lobar degeneration (FTLD) and Alzheimer disease syndromes. For early identification of individual patients and differential diagnosis, sensitive clinical measures are required that are able to assess patterns of behaviors and detect syndromic differences in both asymptomatic and symptomatic stages. We investigated whether the examiner-based Social Behavior Observer Checklist (SBOCL) is sensitive to early behavior changes and reflects disease severity within and between neurodegenerative syndromes.

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Background And Objectives: To determine how fully automated Elecsys CSF immunoassays for β-amyloid (Aβ) and tau biomarkers and an ultrasensitive Simoa assay for neurofilament light chain (NFL) correlate with neuropathologic changes of Alzheimer disease (AD) and frontotemporal lobar degeneration (FTLD).

Methods: We studied 101 patients with antemortem CSF and neuropathology data. CSF samples were collected a mean of 2.

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Importance: Histone deacetylase inhibitors have been repeatedly shown to elevate progranulin levels in preclinical models. This report describes the first randomized clinical trial of a histone deacetylase inhibitor in frontotemporal dementia (FTD) resulting from progranulin (GRN) gene variations.

Objective: To characterize the safety, tolerability, plasma pharmacokinetics, and pharmacodynamic effects of oral FRM-0334 on plasma progranulin and other exploratory biomarkers, including fluorodeoxyglucose (FDG)-positron emission tomography (PET), in individuals with GRN haploinsufficiency.

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Progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS; the most common phenotype of corticobasal degeneration) are tauopathies with a relentless course, usually starting in the mid-60s and leading to death after an average of 7 years. There is as yet no specific or disease-modifying treatment. Clinical deficits in PSP are numerous, involve the entire neuraxis, and present as several discrete phenotypes.

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Objective: We tested the hypothesis that plasma neurofilament light chain (NfL) identifies asymptomatic carriers of familial frontotemporal lobar degeneration (FTLD)-causing mutations at risk of disease progression.

Methods: Baseline plasma NfL concentrations were measured with single-molecule array in original (n = 277) and validation (n = 297) cohorts. , , and mutation carriers and noncarriers from the same families were classified by disease severity (asymptomatic, prodromal, and full phenotype) using the CDR Dementia Staging Instrument plus behavior and language domains from the National Alzheimer's Disease Coordinating Center FTLD module (CDR+NACC-FTLD).

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While behavioral variant frontotemporal dementia (bvFTD) and primary progressive aphasia (PPA) remain unrelenting and universally fatal conditions, there is a framework for supportive treatment in patients diagnosed with these frontotemporal dementia (FTD) syndromes and the larger spectrum of clinical syndromes associated with frontotemporal lobar degeneration (FTLD) pathology on autopsy. A managing physician has an important role in weighing therapeutic options, organizing caregiver support, and framing long-term expectations for patients and caregivers. Additionally, a dedicated neurologist may assist patients and caregivers in navigating a growing range of FTD research, including exciting opportunities in clinical therapeutic trials.

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Introduction: Amyloid-related imaging abnormalities (ARIA) are a common, dose-dependent effect of amyloid-targeting antibodies, strongly associated with the apolipoprotein E (APOE) ε4 allele.

Methods: We describe the clinical course and management of a 66-year-old white male (APOE ε4/ε4) enrolled in an observational study that included amyloid and tau positron emission tomography (PET), who received aducanumab through the ENGAGE clinical trial.

Results: Acute symptoms included headache and encephalopathy, and magnetic resonance imaging revealed ARIA-E and ARIA-H.

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Four-repeat tauopathies are a neurodegenerative disease characterized by brain parenchymal accumulation of a specific isoform of the protein tau, which gives rise to a wide breadth of clinical syndromes encompassing diverse symptomatology, with the most common syndromes being progressive supranuclear palsy-Richardson's and corticobasal syndrome. Despite the lack of effective disease-modifying therapies, targeted treatment of symptoms can improve quality of life for patients with 4-repeat tauopathies. However, managing these symptoms can be a daunting task, even for those familiar with the diseases, as they span motor, sensory, cognitive, affective, autonomic, and behavioral domains.

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Background: Progressive supranuclear palsy (PSP) is a neurodegenerative disease without approved therapies, and therapeutics are often tried off-label in the hope of slowing disease progression. Results from these experiences are seldom shared, which limits evidence-based knowledge to guide future treatment decisions.

Objectives: To describe an open-label experience, including safety/tolerability, and longitudinal changes in biomarkers of disease progression in PSP-Richardson's syndrome (PSP-RS) patients treated with either salsalate or young plasma and compare to natural history data from previous multicenter studies.

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Introduction: Identifying clinical measures that track disease in the earliest stages of frontotemporal lobar degeneration (FTLD) is important for clinical trials. Familial FTLD provides a unique paradigm to study early FTLD. Executive dysfunction is a clinically relevant hallmark of FTLD and may be a marker of disease progression.

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Introduction: The Advancing Research and Treatment for Frontotemporal Lobar Degeneration (ARTFL) and Longitudinal Evaluation of Familial Frontotemporal Dementia Subjects (LEFFTDS) consortia are two closely connected studies, involving multiple North American centers that evaluate both sporadic and familial frontotemporal dementia (FTD) participants and study longitudinal changes.

Methods: We screened the major dementia-associated genes in 302 sporadic and 390 familial (symptomatic or at-risk) participants enrolled in these studies.

Results: Among the sporadic patients, 16 (5.

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Introduction: Conventional Z-scores are generated by subtracting the mean and dividing by the standard deviation. More recent methods linearly correct for age, sex, and education, so that these "adjusted" Z-scores better represent whether an individual's cognitive performance is abnormal. Extreme negative Z-scores for individuals relative to this normative distribution are considered indicative of cognitive deficiency.

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Importance: Individuals with tuberous sclerosis complex can develop a progressive neuropsychiatric syndrome known as tuberous sclerosis-associated neuropsychiatric disorders. Tuberous sclerosis-associated neuropsychiatric disorders symptoms overlap with clinical criteria for frontotemporal dementia, yet the association between the 2 has not been explored.

Objective: To investigate the potential association between tuberous sclerosis-associated neuropsychiatric disorders and frontotemporal dementia.

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