Melbourne School of Psychological Sciences - Research Publications
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ItemPlasma neurofilament light in behavioural variant frontotemporal dementia compared to mood and psychotic disorders(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.
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ItemMethodological considerations for observational studies of treatment effectiveness in neurology: a clinician's guide(BMJ PUBLISHING GROUP, 2024-05)Data from cohorts, registries, randomised trials, electronic medical records and administrative claims databases have increasingly been used to inform the use of therapies for neurological diseases. While novel sophisticated methods are enabling us to use existing data to guide treatment decisions, the complexity of statistical methodology is making appraisal of clinical evidence increasingly demanding. In this narrative review, we provide a brief overview of the most commonly used methods for evaluation of treatment effectiveness in neurology. This primer discusses complementarity of randomised and non-randomised study designs, sources of observational data, different forms of bias and the appropriate mitigation strategies, statistical significance, Bayesian approaches and provides an overview of multivariable regression models, propensity score-based models, causal inference, mediation analysis and Mendelian randomisation.
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ItemNo Preview AvailableA phase 1b open label study of sodium selenate as a diseaseāmodifying treatment for behavioural variant frontoātemporal dementia(Wiley, 2021-12)Abstract Background Hyperphosphorylated tau is a pathological hallmark of ā¼45% of behavioural variant frontotemporal dementia (bvFTD). For this reason, hyperphosphorylated tau represents a promising treatment target for this population. Sodium selenate stimulates the PP2A enzyme, which directly dephosphorylates hyperphosphorylated tau. This Phase 1b, openālabelled, study investigated sodium selenate as a diseaseāmodifying treatment for patients with bvFTD. Method Twelve patients with bvFTD were treated with sodium selenate (15mg tds) for twelve months. Participants underwent a cognitive and behavioural battery, MRI, lumbar puncture and safety assessments at screening, baseline, and at regular intervals following treatment commencement. Adverse events were monitored via diary cards between clinic visits. Result All 12 patients completed the study. Safety analysis found that sodium selenate was safe and well tolerated, with no study withdrawals. Commonly reported mildāmoderate adverse events were nail changes (n=6), muscles aches (n=4), headache, fatigue, hair loss and fall (n=3). Five patients reduced their dose to 10mg tds due to adverse events. No treatmentārelated serious adverse events occurred. Analyses of efficacy data are ongoing. A mixedāeffects analysis showed an overall small but significant decline on cognition and behaviour, including total NUCOG score (b=ā0.18, 95% CI=ā0.28ā0.08) Cambridge Behavioural Index (b=0.32, 95% CI=0.18ā0.46) and Carer Burden Scale score (b=0.1, 95% CI = 0.02ā0.18). Percentage change in wholeābrain volume from baseline to week 52 ranged from ā0.26% to ā6.51% (n=7 >ā1.8%, n=4 <ā1.8%). Plasma tau levels (n=6) did not change from baseline (3.73Ā±0.26pg/mL) to week 52 (4.66Ā±0.24pg/mL). CSF tau also showed no change from baseline (167.8Ā±11.2pg/mL) to week 52 (156.1Ā±2.49pg/mL). Although not significant, the directional changes are in line with the proposed mechanism of sodium selenate. Exploratory analyses of ārespondersā (brain volume change >ā1.8%, n=7) found no change in NUCOG total score (b=ā0.03, 95% CI ā0.14ā0.07) or CBS score (b=ā0.05, 95% CI ā0.04ā0.13) over time. Conclusion Sodium selenate is safe and well tolerated in patients with bvFTD. Exploratory analyses indicate it may reduce atrophy and halt cognitive decline in a subset of bvFTD patients. Sodium selenate should be further investigated as a potential treatment for bvFTD, and biomarkers to identify the subset of āresponderā patients explored.
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ItemNo Preview AvailableThe diagnostic challenge among young onset dementia syndromes and primary psychiatric diseases: Results of a retrospective, 20āyear crossāsectional study(Wiley, 2021-12)Abstract Background Distinguishing a dementia syndrome from a primary psychiatric disease in younger patients can be challenging and may lead to diagnostic change over time. The aim of this study was to examine diagnostic stability in a cohort of patients with youngerāonset neurocognitive disorders. Method We retrospectively reviewed records of patients that were admitted to our unit between 2000 and 2019, were followedāup for ā„12 months and received a diagnosis of young onset dementia at any time point. Initial diagnosis included Alzheimer disease (AD)ātype dementia (n= 30), frontotemporal dementia (FTD) syndromes (n=44), vascular dementia (VaD, n=7), mild cognitive impairment (MCI, n= 10), primary psychiatric diseases (n=6) and other conditions such as Lewy Body Dementia (n=30). Result In a total of n=127 patients, 49 (39%) changed their initial diagnoses during followāup. Behavioural variant FTD (bvFTD) was the least stable diagnosis, followed by dementia not otherwise specified and MCI. Compared to patients with a stable diagnosis, those who changed exhibited: a higher cognitive score at baseline, a longer followāup period, greater delay to final diagnosis, and no family history of dementia. Patients switching from a neurodegenerative to a psychiatric diagnosis more likely had a long psychiatric history, while those changing from a psychiatric to a neurodegenerative diagnosis had a recent manifestation of psychiatric symptoms. Conclusion Misdiagnosis in younger patients with neurocognitive disorders is not uncommon, especially in cases of behavioural variant FTD. Lateāonset psychiatric symptoms may be the harbinger to a neurodegenerative disease. Close followāup and monitoring of these patients are necessary.
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ItemEffect of Disease-Modifying Therapy on Disability in Relapsing-Remitting Multiple Sclerosis Over 15 Years(LIPPINCOTT WILLIAMS & WILKINS, 2021-02-02)OBJECTIVE: To test the hypothesis that immunotherapy prevents long-term disability in relapsing-remitting multiple sclerosis (MS), we modeled disability outcomes in 14,717 patients. METHODS: We studied patients from MSBase followed for ā„1 year, with ā„3 visits, ā„1 visit per year, and exposed to MS therapy, and a subset of patients with ā„15-year follow-up. Marginal structural models were used to compare the cumulative hazards of 12-month confirmed increase and decrease in disability, Expanded Disability Status Scale (EDSS) step 6, and the incidence of relapses between treated and untreated periods. Marginal structural models were continuously readjusted for patient age, sex, pregnancy, date, disease course, time from first symptom, prior relapse history, disability, and MRI activity. RESULTS: A total of 14,717 patients were studied. During the treated periods, patients were less likely to experience relapses (hazard ratio 0.60, 95% confidence interval [CI] 0.43-0.82, p = 0.0016), worsening of disability (0.56, 0.38-0.82, p = 0.0026), and progress to EDSS step 6 (0.33, 0.19-0.59, p = 0.00019). Among 1,085 patients with ā„15-year follow-up, the treated patients were less likely to experience relapses (0.59, 0.50-0.70, p = 10-9) and worsening of disability (0.81, 0.67-0.99, p = 0.043). CONCLUSION: Continued treatment with MS immunotherapies reduces disability accrual by 19%-44% (95% CI 1%-62%), the risk of need of a walking aid by 67% (95% CI 41%-81%), and the frequency of relapses by 40-41% (95% CI 18%-57%) over 15 years. This study provides evidence that disease-modifying therapies are effective in improving disability outcomes in relapsing-remitting MS over the long term. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that, for patients with relapsing-remitting MS, long-term exposure to immunotherapy prevents neurologic disability.
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ItemEffectiveness of multiple disease-modifying therapies in relapsing-remitting multiple sclerosis: causal inference to emulate a multiarm randomised trial(BMJ PUBLISHING GROUP, 2023-12)BACKGROUND: Simultaneous comparisons of multiple disease-modifying therapies for relapsing-remitting multiple sclerosis (RRMS) over an extended follow-up are lacking. Here we emulate a randomised trial simultaneously comparing the effectiveness of six commonly used therapies over 5 years. METHODS: Data from 74 centres in 35 countries were sourced from MSBase. For each patient, the first eligible intervention was analysed, censoring at change/discontinuation of treatment. The compared interventions included natalizumab, fingolimod, dimethyl fumarate, teriflunomide, interferon beta, glatiramer acetate and no treatment. Marginal structural Cox models (MSMs) were used to estimate the average treatment effects (ATEs) and the average treatment effects among the treated (ATT), rebalancing the compared groups at 6-monthly intervals on age, sex, birth-year, pregnancy status, treatment, relapses, disease duration, disability and disease course. The outcomes analysed were incidence of relapses, 12-month confirmed disability worsening and improvement. RESULTS: 23ā236 eligible patients were diagnosed with RRMS or clinically isolated syndrome. Compared with glatiramer acetate (reference), several therapies showed a superior ATE in reducing relapses: natalizumab (HR=0.44, 95% CI=0.40 to 0.50), fingolimod (HR=0.60, 95% CI=0.54 to 0.66) and dimethyl fumarate (HR=0.78, 95% CI=0.66 to 0.92). Further, natalizumab (HR=0.43, 95% CI=0.32 to 0.56) showed a superior ATE in reducing disability worsening and in disability improvement (HR=1.32, 95% CI=1.08 to 1.60). The pairwise ATT comparisons also showed superior effects of natalizumab followed by fingolimod on relapses and disability. CONCLUSIONS: The effectiveness of natalizumab and fingolimod in active RRMS is superior to dimethyl fumarate, teriflunomide, glatiramer acetate and interferon beta. This study demonstrates the utility of MSM in emulating trials to compare clinical effectiveness among multiple interventions simultaneously.
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ItemNo Preview AvailableCerebrospinal fluid neurofilament light predicts longitudinal diagnostic change in patients with psychiatric and neurodegenerative disorders(CAMBRIDGE UNIV PRESS, 2024-02)OBJECTIVE: People with neuropsychiatric symptoms often experience delay in accurate diagnosis. Although cerebrospinal fluid neurofilament light (CSF NfL) shows promise in distinguishing neurodegenerative disorders (ND) from psychiatric disorders (PSY), its accuracy in a diagnostically challenging cohort longitudinally is unknown. METHODS: We collected longitudinal diagnostic information (mean = 36 months) from patients assessed at a neuropsychiatry service, categorising diagnoses as ND/mild cognitive impairment/other neurological disorders (ND/MCI/other) and PSY. We pre-specified NfL > 582 pg/mL as indicative of ND/MCI/other. RESULTS: Diagnostic category changed from initial to final diagnosis for 23% (49/212) of patients. NfL predicted the final diagnostic category for 92% (22/24) of these and predicted final diagnostic category overall (ND/MCI/other vs. PSY) in 88% (187/212), compared to 77% (163/212) with clinical assessment alone. CONCLUSIONS: CSF NfL improved diagnostic accuracy, with potential to have led to earlier, accurate diagnosis in a real-world setting using a pre-specified cut-off, adding weight to translation of NfL into clinical practice.
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ItemNo Preview AvailableSelective perforant-pathway atrophy in Huntington disease: MRI analysis of hippocampal subfields(WILEY, 2023-09)INTRODUCTION: While individuals with Huntington disease (HD) show memory impairment that indicates hippocampal dysfunction, the available literature does not consistently identify structural evidence for involvement of the whole hippocampus but rather suggests that hippocampal atrophy may be confined to certain hippocampal subregions. METHODS: We processed T1-weighted MRI from IMAGE-HD study using FreeSurfer 7.0 and compared the volumes of the hippocampal subfields among 36 early motor symptomatic (symp-HD), 40 pre-symptomatic (pre-HD), and 36 healthy control individuals across three timepoints over 36āmonths. RESULTS: Mixed-model analyses revealed significantly lower subfield volumes in symp-HD, compared with pre-HD and control groups, in the subicular regions of the perforant-pathway: presubiculum, subiculum, dentate gyrus, tail, and right molecular layer. These adjoining subfields aggregated into a single principal component, which demonstrated an accelerated rate of atrophy in the symp-HD. Volumes between pre-HD and controls did not show any significant difference. In the combined HD groups, CAG repeat length and disease burden score were associated with presubiculum, molecular layer, tail, and perforant-pathway subfield volumes. Hippocampal left tail and perforant-pathway subfields were associated with motor onset in the pre-HD group. CONCLUSIONS: Hippocampal subfields atrophy in early symptomatic HD affects key regions of the perforant-pathway, which may implicate the distinctive memory impairment at this stage of illness. Their volumetric associations with genetic and clinical markers suggest the selective susceptibility of these subfields to mutant Huntingtin and disease progression.
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ItemDisability accrual in primary and secondary progressive multiple sclerosis(BMJ Publishing Group, 2023-04-17)Background: Some studies comparing primary and secondary progressive multiple sclerosis (PPMS, SPMS) report similar ages at onset of the progressive phase and similar rates of subsequent disability accrual. Others report later onset and/or faster accrual in SPMS. Comparisons have been complicated by regional cohort effects, phenotypic differences in sex ratio and management and variable diagnostic criteria for SPMS. Methods: We compared disability accrual in PPMS and operationally diagnosed SPMS in the international, clinic-based MSBase cohort. Inclusion required PPMS or SPMS with onset at age ā„18 years since 1995. We estimated Andersen-Gill hazard ratios for disability accrual on the Expanded Disability Status Scale (EDSS), adjusted for sex, age, baseline disability, EDSS score frequency and drug therapies, with centre and patient as random effects. We also estimated ages at onset of the progressive phase (Kaplan-Meier) and at EDSS milestones (Turnbull). Analyses were replicated with physician-diagnosed SPMS. Results: Included patients comprised 1872 with PPMS (47% men; 50% with activity) and 2575 with SPMS (32% men; 40% with activity). Relative to PPMS, SPMS had older age at onset of the progressive phase (median 46.7 years (95% CI 46.2-47.3) vs 43.9 (43.3-44.4); p<0.001), greater baseline disability, slower disability accrual (HR 0.86 (0.78-0.94); p<0.001) and similar age at wheelchair dependence. Conclusions: We demonstrate later onset of the progressive phase and slower disability accrual in SPMS versus PPMS. This may balance greater baseline disability in SPMS, yielding convergent disability trajectories across phenotypes. The different rates of disability accrual should be considered before amalgamating PPMS and SPMS in clinical trials.
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ItemRituximab vs Ocrelizumab in Relapsing-Remitting Multiple Sclerosis(AMER MEDICAL ASSOC, 2023-08)IMPORTANCE: Ocrelizumab, a humanized monoclonal antibody targeted against CD20+ B cells, reduces the frequency of relapses by 46% and disability worsening by 40% compared with interferon beta 1a in relapsing-remitting multiple sclerosis (MS). Rituximab, a chimeric monoclonal anti-CD20 agent, is often prescribed as an off-label alternative to ocrelizumab. OBJECTIVE: To evaluate whether the effectiveness of rituximab is noninferior to ocrelizumab in relapsing-remitting MS. DESIGN, SETTING, AND PARTICIPANTS: This was an observational cohort study conducted between January 2015 and March 2021. Patients were included in the treatment group for the duration of study therapy and were recruited from the MSBase registry and Danish MS Registry (DMSR). Included patients had a history of relapsing-remitting MS treated with ocrelizumab or rituximab, a minimum 6 months of follow-up, and sufficient data to calculate the propensity score. Patients with comparable baseline characteristics were 1:6 matched with propensity score on age, sex, MS duration, disability (Expanded Disability Status Scale), prior relapse rate, prior therapy, disease activity (relapses, disability accumulation, or both), magnetic resonance imaging lesion burden (missing values imputed), and country. EXPOSURE: Treatment with ocrelizumab or rituximab after 2015. MAIN OUTCOMES AND MEASURES: Noninferiority comparison of annualized rate of relapses (ARRs), with a prespecified noninferiority margin of 1.63 rate ratio. Secondary end points were relapse and 6-month confirmed disability accumulation in pairwise-censored groups. RESULTS: Of the 6027 patients with MS who were treated with ocrelizumab or rituximab, a total of 1613 (mean [SD] age; 42.0 [10.8] years; 1089 female [68%]) fulfilled the inclusion criteria and were included in the analysis (898 MSBase, 715 DMSR). A total of 710 patients treated with ocrelizumab (414 MSBase, 296 DMSR) were matched with 186 patients treated with rituximab (110 MSBase, 76 DMSR). Over a pairwise censored mean (SD) follow-up of 1.4 (0.7) years, the ARR ratio was higher in patients treated with rituximab than in those treated with ocrelizumab (rate ratio, 1.8; 95% CI, 1.4-2.4; ARR, 0.20 vs 0.09; Pā<ā.001). The cumulative hazard of relapses was higher among patients treated with rituximab than those treated with ocrelizumab (hazard ratio, 2.1; 95% CI, 1.5-3.0). No difference in the risk of disability accumulation was observed between groups. Results were confirmed in sensitivity analyses. CONCLUSION: In this noninferiority comparative effectiveness observational cohort study, results did not show noninferiority of treatment with rituximab compared with ocrelizumab. As administered in everyday practice, rituximab was associated with a higher risk of relapses than ocrelizumab. The efficacy of rituximab and ocrelizumab administered at uniform doses and intervals is being further evaluated in randomized noninferiority clinical trials.
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