Publications by authors named "David Darby"

Background: Upper limb dysfunction is a common debilitating feature of relapsing-remitting multiple sclerosis (RRMS). We aimed to examine the longitudinal trajectory of the iPad®-based Manual Dexterity Test (MDT) and predictors of change over time.

Methods: We prospectively enrolled RRMS patients (limited to Expanded Disability Status Scale (EDSS) < 4).

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Objective: Timely, accurate distinction between behavioural variant frontotemporal dementia (bvFTD) and primary psychiatric disorders (PPD) is a clinical challenge. Blood biomarkers such as neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) have shown promise. Prior work has shown NfL helps distinguish FTD from PPD.

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Article Synopsis
  • The study examines the types of diagnoses given to patients referred for frontal network impairments at a cognitive neurology clinic in Melbourne, specifically looking into cases suspected of frontotemporal dementia (FTD).
  • Out of 161 patients analyzed over a decade, the most common final diagnosis was an FTD syndrome, with behavioral variant FTD being the most frequent sub-type.
  • Other diagnoses included primary psychiatric disorders, vascular cognitive impairment, and Alzheimer's disease, with behavioral variant FTD patients showing higher rates of medical comorbidities.
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Deficits in memory performance have been linked to a wide range of neurological and neuropsychiatric conditions. While many studies have assessed the memory impacts of individual conditions, this study considers a broader perspective by evaluating how memory recall is differentially associated with nine common neuropsychiatric conditions using data drawn from 55 international studies, aggregating 15,883 unique participants aged 15-90. The effects of dementia, mild cognitive impairment, Parkinson's disease, traumatic brain injury, stroke, depression, attention-deficit/hyperactivity disorder (ADHD), schizophrenia, and bipolar disorder on immediate, short-, and long-delay verbal learning and memory (VLM) scores were estimated relative to matched healthy individuals.

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Introduction: Cognitive symptoms are reported commonly throughout all phases of a migraine; however, there is a paucity of objective cognitive profiling. Previous studies have been limited by practice effect, and variable populations.

Methods: Participants completed 1 month of daily testing with a computerised cognitive battery involving a simple reaction (SRT), choice reaction (CRT) and a working memory test (WM).

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Objective: Socio-emotional skills, including social competence and social cognition, form the basis for robust relationships and wellbeing. Despite their importance, these skills are poorly defined and measured, particularly in children with developmental vulnerabilities. As a consequence, targets for effective management and treatment remain unclear.

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Cognitive impairment in multiple sclerosis (MS) affects approximately 40-70% of patients and can have varying degrees of severity. Even mild cognitive impairment can impact on quality of life and productivity. Despite this, patients are not routinely screened or monitored for cognitive impairment in Australia due to a range of issues, with time and space being the main limiting factors.

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Background And Purpose: The validity, reliability, and longitudinal performance of the Patient-Determined Disease Steps (PDDS) scale is unknown in people with multiple sclerosis (MS) with mild to moderate disability. We aimed to examine the psychometric properties and longitudinal performance of the PDDS.

Methods: We included relapsing-remitting MS patients with an Expanded Disability Status Scale (EDSS) score of less than 4.

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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, = 42), bipolar affective disorder (BPAD, = 121), treatment-resistant schizophrenia (TRS, = 82), bvFTD ( = 22), and compared to the reference cohort (Control Group 2, = 1926, using GAMLSS modelling), and age-matched controls (Control Group 1, = 96, using general linear models).

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Article Synopsis
  • Researchers in neuroscience are using Big Data to improve the reliability and replication of cognitive studies, focusing on memory testing.
  • They conducted a mega-analysis with data from 53 studies, involving over 10,500 individuals, employing methods to harmonize data and reduce variability across different sites.
  • Their findings show that large-scale data sharing can enhance the reproducibility of research in behavioral sciences, and they offer a free conversion tool for this purpose.
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Article Synopsis
  • - A 30-something man with a fever and rash suddenly lost his vision, leading to a diagnosis of cortical blindness after neurological examination and MRI revealed issues in the occipital region.
  • - Further investigation uncovered a history of untreated systemic lupus erythematosus, which contributed to central nervous system lupus as the underlying cause of his visual loss.
  • - The patient was treated with pulse methylprednisolone and cyclophosphamide, resulting in a significant recovery of his vision within days, and he was managed with ongoing medications to prevent relapses.
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Background: Frontotemporal dementia (FTD) syndromes, mimics, phenocopy (phFTD), and slowly progressive behavioral variant FTD (bvFTD) can be difficult to distinguish clinically. Biomarkers such as neurofilament light chain (NfL) may be helpful.

Objective: To study plasma NfL levels in people with FTD syndromes and determine if plasma NfL can distinguish between FTD syndromes and phFTD.

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Background: In the clinical setting, identification of the genetic cause in patients with early-onset dementia (EOD) is challenging due to multiple types of genetic tests required to arrive at a diagnosis. Whole-genome sequencing (WGS) has the potential to serve as a single diagnostic platform, due to its superior ability to detect common, rare and structural genetic variation.

Methods: WGS analysis was performed in 50 patients with EOD.

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Introduction: Sodium selenate increases tau dephosphorylation through protein phosphatase 2 activation. Here we report an open-label Phase 1b study of sodium selenate as a disease-modifying treatment for behavioral variant frontotemporal dementia (bvFTD).

Methods: Twelve participants with bvFTD received sodium selenate (15 mg, three times a day) for 52 weeks.

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Background: Perceived cognitive impairment in MS is associated with adverse changes in employment capacity, sexual function, and aspects of daily living. Studies have shown relationships between perceived cognitive impairment and objective neuropsychological functioning and mood. Subjective cognitive performance in people with MS has not previously been compared to their objective performance on a computerised cognitive battery.

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Introduction: Progressive supranuclear palsy (PSP) is a neurodegenerative disorder for which there are currently no disease-modifying therapies. The neuropathology of PSP is associated with the accumulation of hyperphosphorylated tau in the brain. We have previously shown that protein phosphatase 2 activity in the brain is upregulated by sodium selenate, which enhances dephosphorylation.

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Stroke survivors are at high risk of dementia, associated with increasing age and vascular burden and with pre-existing cognitive impairment, older age. Brain atrophy patterns are recognised as signatures of neurodegenerative conditions, but the natural history of brain atrophy after stroke remains poorly described. We sought to determine whether stroke survivors who were cognitively normal at time of stroke had greater total brain (TBV) and hippocampal volume (HV) loss over 3 years than controls.

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Background And Objectives: Longitudinal cognitive trajectories in multiple sclerosis are heterogeneous and difficult to measure. We aimed to identify discrete longitudinal reaction time trajectories in relapsing-remitting multiple sclerosis using a computerized cognitive battery and to assess the association between trajectories of reaction time and disability progression.

Methods: All participants serially completed computerized reaction time tasks measuring psychomotor speed, visual attention, and working memory.

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Introduction: Behavioural variant frontotemporal dementia (bvFTD) is a neurodegenerative disorder often neuropathologically associated with the accumulation of abnormally hyperphosphorylated tau, for which there is currently no disease-modifying treatment. Previous work by our group has shown sodium selenate upregulates the activity of protein phosphatase 2 in the brain, increasing the rate of tau dephosphorylation. The objective of this study is to evaluate the efficacy and safety of sodium selenate as a disease-modifying treatment for bvFTD.

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Objectives: The criteria for objective memory impairment in mild cognitive impairment (MCI) are vaguely defined. Aggregating the number of abnormal memory scores (NAMS) is one way to operationalise memory impairment, which we hypothesised would predict progression to Alzheimer's disease (AD) dementia.

Methods: As part of the Australian Imaging, Biomarkers and Lifestyle Flagship Study of Ageing, 896 older adults who did not have dementia were administered a psychometric battery including three neuropsychological tests of memory, yielding 10 indices of memory.

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Background: Monitoring and screening of cognitive function in the ambulatory setting requires simple, brief cognitive tests that are reproducible. MSReactor (MSR) is a web-based platform that screens psychomotor (processing) speed, attention and working memory using a game-like interface. The Processing Speed Test (PST) is a validated computerized version of the Symbol Digit Modalities test (SDMT) and component of the Multiple Sclerosis Performance Test (MSPT).

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Background: Chronic migraine is a disabling condition, often associated with comorbidities including cognitive dysfunction, anxiety and depression. It is unclear whether cognitive complaints are associated with the underlying migraine pathophysiological process or related to drugs or comorbidities of depression and anxiety.

Objective: To evaluate cognitive changes in chronic migraine and assess reversibility of cognitive dysfunction following effective migraine treatment using onabotulinumtoxinA.

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Background: Multiple sclerosis (MS) cognitive tests are resource intensive and limited by practice effects that prevent frequent retesting. Brief, reliable and valid monitoring tools are urgently needed to detect subtle, subclinical cognitive changes in people with MS. Cognitive monitoring over time could contribute to a new definition of disease progression, supplementing routine clinical monitoring.

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