The Diagnostic Challenge of Young-Onset Dementia Syndromes and Primary Psychiatric Diseases: Results From a Retrospective 20-Year Cross-Sectional Study

Blood biomarker profiles in young-onset neurocognitive disorders: A cohort study

INTRODUCTION

Young-onset neurocognitive symptoms result from a heterogeneous group of neurological and psychiatric disorders which present a diagnostic challenge. To identify such factors, we analysed the Biomarkers in Younger-Onset Neurocognitive Disorders cohort, a study of individuals <65 years old presenting with neurocognitive symptoms for a diagnosis and who have undergone cognitive and biomarker analyses.

METHODS

Sixty-five participants (median age at assessment of 56 years, 45% female) were recruited during their index presentation to the Royal Melbourne Hospital Neuropsychiatry Centre, a tertiary specialist service in Melbourne, Australia, and categorized as either early-onset Alzheimer's disease (n = 18), non-Alzheimer's disease neurodegeneration (n = 23) or primary psychiatric disorders (n = 24). Levels of neurofilament light chain, glial fibrillary acidic protein and phosphorylated-tau 181, apolipoprotein E genotype and late-onset Alzheimer's disease polygenic risk scores were determined. Information-theoretic model selection identified discriminatory factors.

RESULTS

Neurofilament light chain, glial fibrillary acidic protein and phosphorylated-tau 181 levels were elevated in early-onset Alzheimer's disease compared with other diagnostic categories. A multi-omic model selection identified that a combination of cognitive and blood biomarkers, but not the polygenic risk score, discriminated between early-onset Alzheimer's disease and primary psychiatric disorders (area under the curve ⩾ 0.975, 95% confidence interval: 0.825-1.000). Phosphorylated-tau 181 alone significantly discriminated between early-onset Alzheimer's disease and non-Alzheimer's disease neurodegeneration causes (area under the curve = 0.950, 95% confidence interval: 0.877-1.00).

DISCUSSION

Discriminating between early-onset Alzheimer's disease, non-Alzheimer's disease neurodegeneration and primary psychiatric disorders causes of young-onset neurocognitive symptoms is possible by combining cognitive profiles with blood biomarkers. These results support utilizing blood biomarkers for the work-up of young-onset neurocognitive symptoms and highlight the need for the development of a young-onset Alzheimer's disease-specific polygenic risk score.

Accurate DNA Methylation Predictor for C9orf72 Repeat Expansion Alleles in the Pathogenic Range

The hexanucleotide (G 4 C 2 ) repeat expansion in the promoter region of C9orf72 is the most frequent genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). In this study, we conducted a genome-wide DNA methylation (DNAm) analysis using EPIC version 2 (EPICv2) arrays on an FTD cohort comprising 27 carriers and 250 non-carriers of the pathogenic C9orf72 repeat expansion from the Amsterdam Dementia Cohort. We identified differentially methylated CpGs probes associated with the pathogenic C9orf72 expansion and used these findings to create a DNAm Least Absolute Shrinkage and Selection Operator (LASSO) predictor to identify repeat expansion carriers. Eight CpG sites at the C9orf72 locus were significantly differentially hypermethylated in repeat expansion carriers compared to non-carriers. The LASSO model predicted repeat expansion status with an average accuracy of 98.6%. The LASSO predictor was further validated in an independent cohort of 2,548 subjects with available EPICv2 data, identifying four C9orf72 repeat expansion carriers, subsequently confirmed by repeat-primed PCR. This result not only illustrates the accuracy of the DNAm predictor of C9orf72 repeat expansion carriers but also suggests that repeat expansion carriers may be more prevalent than expected. The identification of a highly accurate DNAm biomarker for a repeat expansion locus associated with neurodegenerative disorders may provide great value for studying this locus. The approach holds significant promise for investigating this and other repeat expansion loci, particularly given the growing interest in epigenetic epidemiological studies involving large cohorts with available DNAm data.

Graphical abstract optional

Biofluid biomarkers in distinguishing young-onset dementia from primary psychiatric disorders

PURPOSE OF REVIEW

There has been growing interest in the role of biofluid biomarkers to aid the diagnosis of dementia in older people. However, less attention has been given to younger people who have dementia (young-onset dementia), who frequently experience misdiagnoses of primary psychiatric disorders diagnostic delay and challenges accessing appropriate care.

RECENT FINDINGS

We describe 12 studies from the previous 2 years of which the majority have investigated the role of neurofilament light chain protein (NfL) in blood and cerebrospinal fluid in distinguishing young-onset dementia from primary psychiatric disorders. Synaptic and astrocytic biomarkers were also investigated. Sample sizes ranged from n = 46 to n = 999 and studies were mostly from Australia and the Netherlands.

SUMMARY

The major finding from this review was that NfL has very high sensitivity and specificity in differentiating a range of young-onset dementias (Alzheimer's dementia, behavioural-variant frontotemporal dementia) from PPD (schizophrenia, bipolar affective and major depressive disorders). NfL is easily accessible via the blood, so there is significant potential that a blood test could be available to make this dichotomisation. Further research is required to support clinical translation such as changes of NfL with disease progression and standardising analytic techniques.

Factors associated with true-positive and false-positive diagnoses of behavioural variant frontotemporal dementia in 100 consecutive referrals from specialist physicians

BACKGROUND

The behavioural variant of frontotemporal dementia (bvFTD) is a challenging diagnosis due to overlapping symptoms with psychiatric and other neurological conditions. Accordingly, misdiagnosis is common. The present study aimed to identify clinical factors contributing to misdiagnoses of bvFTD by specialist physicians.

METHODS

We retrospectively analysed 100 consecutive referrals by specialist physicians (primarily psychiatrists, neurologists and geriatricians) to a tertiary cognitive disorders clinic specializing in frontotemporal lobar degenerative disorders. Patients were included if the referring specialist suspected bvFTD or if bvFTD was confirmed as the final diagnosis. Diagnostic factors were assessed by comparing the initial referral information with final clinical diagnoses.

RESULTS

Of the 100 patients, 34 were true-positive and 66 were false-positive for bvFTD. False-positive diagnoses were often based on misinterpretation of neuroimaging, particularly nuclear imaging (FDG-PET and HMPAO-SPECT), where subjective interpretation errors led to incorrect bvFTD diagnoses in 32 patients. Cognitive testing also contributed to misdiagnosis, with formal neuropsychological testing incorrectly leading to a bvFTD diagnosis in 20 patients. Patients with prior psychiatric histories were more likely to be misdiagnosed. Observable behavioural features of bvFTD and physical neurological signs were significantly more prevalent in true-positive patients.

CONCLUSIONS

Misinterpretation of neuroimaging and cognitive testing, in particular formal neuropsychological testing, significantly contributed to false-positive bvFTD diagnoses. Physicians should be cautious not to over-interpret neuroimaging and neuropsychology studies and be wary of patients with prior psychiatric histories. In contrast, greater weight should be placed on objective clinical observations of behavioural signs of bvFTD and the emergence of physical neurological signs.

Plasma neurofilament light outperforms glial fibrillary acidic protein in differentiating behavioural variant frontotemporal dementia from primary psychiatric disorders

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. Few studies have assessed NfL together with GFAP.

METHODS

We investigated plasma GFAP and NfL levels in participants with bvFTD, bipolar affective disorder (BPAD), major depressive disorder (MDD), treatment-resistant schizophrenia (TRS), healthy controls (HC), adjusting for age and sex. We compared ability of GFAP and NfL to distinguish bvFTD from PPD.

RESULTS

Plasma GFAP levels were significantly (all p < 0.001) elevated in bvFTD (n = 22, mean (M) = 273 pg/mL) compared to BPAD (n = 121, M = 96 pg/mL), MDD (n = 42, M = 105 pg/mL), TRS (n = 82, M = 67.9 pg/mL), and HC (n = 120, M = 76.8 pg/mL). GFAP distinguished bvFTD from all PPD with an area under the curve (AUC) of 0.85, 95 % confidence interval [0.76, 0.95]. The optimal cut-off of 105 pg/mL was associated with 73 % specificity and 86 % sensitivity. NfL had AUC 0.95 [0.91, 0.99], 13.3 pg/mL cut-off, 88 % specificity, 86 % sensitivity, and was superior to GFAP (p = 0.02863) and combination of GFAP and NfL (p = 0.04726).

CONCLUSIONS

This study found elevated GFAP levels in bvFTD compared to a large cohort of PPD, but NfL levels exhibited better performance in this distinction. These findings extend the literature on GFAP in bvFTD and build evidence for plasma NfL as a useful biomarker to assist with distinguishing bvFTD from PPD. Utilisation of NfL may improve timely and accurate diagnosis of bvFTD.

Strong diagnostic performance of plasma ptau217 for CSF biomarker-defined young-onset Alzheimer disease in a diagnostically heterogeneous clinical cohort

OBJECTIVE

We investigated diagnostic utility of phosphorylated tau 217 and 181 (ptau217, ptau181), glial fibrillary acidic protein (GFAP), amyloid beta 42 and 40 (Aβ42, Aβ40), and neurofilament light (NfL) to distinguish biomarker-defined Alzheimer disease (AD) from non-AD conditions, in a heterogenous clinical cohort of younger people.

METHODS

Plasma biomarkers were analysed using ultrasensitive technology, and compared in patients with CSF Alzheimer disease profiles (A+T+) to other CSF profiles (Other).

RESULTS

Seventy-nine patients were included, median age 60.8 years: 16 A+T+, 63 Other. Ptau217, ptau181, GFAP were significantly elevated in A+T+ compared to Other (3.67 vs 1.12 pg/mL, 3.87 vs 1.79 pg/mL, 189 vs 80 pg/mL, respectively). ptau217 distinguished AD from Other with 90% accuracy (88% specificity, 100% sensitivity). ptau217 also demonstrated strong diagnostic performance for clinically diagnosed AD.

CONCLUSIONS

Plasma ptau217 has strong diagnostic performance in distinguishing CSF biomarker-defined AD in a clinically relevant, younger cohort of people with symptoms, adding further weight for a simple diagnostic blood test for AD as a cause of a patient's symptoms.

The Diagnostic Challenges of Late-onset Neuropsychiatric Symptoms and Early-onset Dementia: A Clinical and Neuropathological Case Study

The emergence of new-onset neuropsychiatric symptoms in middle age presents a diagnostic challenge, particularly when differentiating between a primary psychiatric disorder and an early neurodegenerative disease. The discrepancy between bedside clinical diagnosis and subsequent neuropathological findings in such cases further highlights the difficulty of accurately predicting pathology, especially when there are no evident focal lesions or changes in brain volume. Here we present the case of a 59-year-old woman with inconclusive neuroimaging who exhibited pronounced neuropsychiatric and behavioral symptoms initially suggestive of a mood disorder, then of behavioral variant frontotemporal dementia. However, upon autopsy, we identified coexisting Lewy body disease pathology and tau-related changes, including argyrophilic grain disease and primary age-related tauopathy. This case illustrates the challenges encountered when diagnosing late-onset neuropsychiatric symptoms, emphasizes the link between such symptoms and early-onset dementia and argyrophilic grain disease, and contributes to our understanding of the impact of mixed neuropathology in this population. Accurate diagnosis is essential for the development of molecular-specific therapies and, as well as for accurate prognosis and enrollment in clinical trials.

Plasma and CSF neurofilament light chain distinguish neurodegenerative from primary psychiatric conditions in a clinical setting

INTRODUCTION

People with neurodegenerative disorders (ND) frequently face diagnostic delay and misdiagnosis. We investigated blood and cerebrospinal fluid (CSF) neurofilament light chain (NfL) to distinguish ND from primary psychiatric disorders (PPD), a common challenge in clinical settings.

METHODS

Plasma and CSF NfL levels were measured and compared between groups, adjusting for age, sex, and weight.

RESULTS

A total of 337 participants were included: 136 ND, 77 PPD, and 124 Controls. Plasma NfL was 2.5-fold elevated in ND compared to PPD and had strong diagnostic performance (area under the curve, [AUC]: 0.86, 81%/85% specificity/sensitivity) that was comparable to CSF NfL (2-fold elevated, AUC: 0.89, 95%/71% specificity/sensitivity). Diagnostic performance was especially strong in younger people (40- < 60 years). Additional findings were cutoffs optimized for sensitivity and specificity, and issues important for future clinical translation.

CONCLUSIONS

This study adds important evidence for a simple blood-based biomarker to assist as a screening test for neurodegeneration and distinction from PPD, in clinical settings.

HIGHLIGHTS

NfL levels were significantly higher in ND versus PPD. Plasma NfL showed strong diagnostic performance, comparable to CSF NfL, to distinguish ND from PPD. Diagnostic performance was higher in younger people, where diagnostic challenges are greater. Further research is needed on analytical and reference range factors, for clinical translation. These findings support a simple screening blood test for neurodegeneration.

A Novel Computerized Flexible Attention Test in Detecting Executive Dysfunction of Patients with Early-Onset Cognitive Impairment and Dementia

OBJECTIVE

The number of computer-based cognitive tests has increased in recent years, but there is a need for tests focusing on the assessment of executive function (EF), as it can be crucial for the identification of early-onset neurodegenerative disorders. This study aims to examine the ability of the Flexible Attention Test (FAT), a new computer-based test battery for detecting executive dysfunction of early-onset cognitive impairment and dementia patients.

METHOD

We analyzed the FAT subtask results in memory clinic patients with cognitive symptom onset at ≤65 years. The patients were divided into four groups: early onset dementia (EOD, n = 48), mild cognitive impairment due to neurological causes (MCI-n, n = 34), MCI due to other causes (MCI-o, n = 99), and subjective cognitive decline (SCD, n = 14). The test accuracy to distinguish EOD patients from other groups was examined, as well as correlations with pen-and-paper EF tests. We also reported the 12-months follow-up results.

RESULTS

The EOD and MCI-n patients performed significantly poorer (p ≤ .002) than those in the MCI-o and SCD groups in most of the FAT subtasks. The accuracies of the FAT subtasks to detect EOD from other causes were mainly moderate (0.34 ≤ area under the curve < 0.74). The FAT subtasks correlated logically with corresponding pen-and-paper EF tests (.15 ≤ r ≤ .75). No systematic learning effects were detected in the FAT performance at follow-up.

CONCLUSIONS

The FAT appears to be a promising method for the precise evaluation of EF and applicable distinguishing early-onset neurodegenerative disorders from patients with other causes of cognitive problems.

Younger people with dementia registered to public mental health services in Victoria, Australia

Objectives Individuals living with young-onset dementia fall through the gaps of adult and geriatric services. Given that non-cognitive symptoms of dementia in younger people are often psychiatric and behavioural in nature, these people may contact mental health services. There is sparse information investigating the frequency of people with young-onset dementia who contact mental health triage in Victoria. Methods Triage data were obtained from the Victorian Agency for Health Information. The data contained demographics for people registered with Victorian mental health services. Consumers who had an International Classification for Diseases code for dementia and were aged less than 65 years were identified as people with young-onset dementia. Using information of the frequency of people with young-onset dementia who were registered with each area-based mental health service, population census statistics were used to make estimates of the frequency of young-onset dementia. Results Of the 6172 people who had a dementia diagnosis, 1020 of them were aged less than 65 years and had young-onset dementia. There were proportionally more men who had young-onset dementia compared to women. There were more people with young-onset dementia registered to rural mental health services compared to metropolitan services. Conclusion Findings provide important information for service planning in Victoria. Recommendations include upskilling and education for the assessment of dementia for those clinicians who work in mental health services, particularly in rural regions.

Plasma extracellular vesicle tau and TDP-43 as diagnostic biomarkers in FTD and ALS

Minimally invasive biomarkers are urgently needed to detect molecular pathology in frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Here, we show that plasma extracellular vesicles (EVs) contain quantifiable amounts of TDP-43 and full-length tau, which allow the quantification of 3-repeat (3R) and 4-repeat (4R) tau isoforms. Plasma EV TDP-43 levels and EV 3R/4R tau ratios were determined in a cohort of 704 patients, including 37 genetically and 31 neuropathologically proven cases. Diagnostic groups comprised patients with TDP-43 proteinopathy ALS, 4R tauopathy progressive supranuclear palsy, behavior variant FTD (bvFTD) as a group with either tau or TDP-43 pathology, and healthy controls. EV tau ratios were low in progressive supranuclear palsy and high in bvFTD with tau pathology. EV TDP-43 levels were high in ALS and in bvFTD with TDP-43 pathology. Both markers discriminated between the diagnostic groups with area under the curve values >0.9, and between TDP-43 and tau pathology in bvFTD. Both markers strongly correlated with neurodegeneration, and clinical and neuropsychological markers of disease severity. Findings were replicated in an independent validation cohort of 292 patients including 34 genetically confirmed cases. Taken together, the combination of EV TDP-43 levels and EV 3R/4R tau ratios may aid the molecular diagnosis of FTD, FTD spectrum disorders and ALS, providing a potential biomarker to monitor disease progression and target engagement in clinical trials.

The experiences and perspectives of older adult mental health professional staff teams when supporting people with young-onset dementia

Background. The diagnosis of young-onset dementia presents significant challenges both for the person and their families, which often differ from the challenges faced with late-onset dementia. Evidence of the experience of service users and carers tends to reveal a negative appraisal of the care received, citing longer diagnosis times, poor clinician knowledge and lack of age-appropriate care. However, evidence looking into staff experiences of supporting someone with young-onset dementia is relatively scarce. The aim of this study was to explore the experiences and reflections of health and social care staff who support people with young-onset dementia within older adult mental health services, and whether their knowledge of the systems they work in could reveal the existence of barriers or facilitators to young-onset dementia care. Methods. Health and social care professionals working with people and carers with young-onset dementia across England were remotely interviewed between September and December 2021. Data were analysed using inductive thematic analysis. Findings. Sixteen staff members were interviewed. Three themes were constructed with six sub-themes. The first theme related to the perception of greater complexity around young-onset dementia support. The second theme describes staff fears around their ability to effectively support people with young-onset dementia, including the perception that young-onset dementia requires specialist input. The final theme describes systemic and structural inefficiencies which provide additional challenges for staff. Conclusions. Providing effective support for people with young-onset dementia and their families requires adjustments both within the clinician role and mental health services. Staff considered young-onset dementia support to be a specialist intervention and felt the services they work for are suited to generic mental health and dementia provision. Findings are discussed with recommendations relating to developing a standardised model of dementia care for young-onset dementia which recognises and responds to the unique experiences of young-onset dementia.

Neuropsychological Profiles, Etiologies, and Medical Comorbidities in Early-Onset Dementia and Cognitive Impairment: A Memory Outpatient Clinic Cohort Study

Background

Although early-onset dementia (EOD) is associated with diagnostic challenges that differ from those of related to late-onset dementia, only limited studies have addressed the neuropsychological and health characteristics or specified the diagnoses underlying early-onset cognitive impairment in a real-world clinical setting.

Objective

To investigate the neuropsychological profiles, etiologies, and comorbidities of an unselected cohort of memory clinic patients (≤65 years at symptom onset).

Methods

The patients' (n = 210) diagnoses were determined based on comprehensive diagnostic workup. Medical comorbidities and neuropsychological profiles were compared between clinically relevant patient groups, namely early-onset dementia (n = 55), mild cognitive impairment due to vascular or suspected neurodegenerative (MCI-n, n = 35) or non-neurodegenerative (MCI-o, n = 106) etiologies, and subjective cognitive decline (n = 14).

Results

The most prevalent diagnoses were Alzheimer's disease (AD, 14%) and depression (11%). Multiple prior medical conditions were common (67%); however, EOD patients had fewer other diagnoses (p = 0.008) than MCI-o patients. Compared to other groups, EOD patients had more severe deficits (p < 0.001) on immediate and delayed memory, processing speed, symptom awareness, and global cognition. AD patients had weaker memory retention ability but less behavioral symptoms than frontotemporal dementia (FTD) patients (p≤0.05). Depression was associated with better immediate memory, symptom awareness, and global cognition than AD and FTD (p < 0.05).

Conclusions

EOD is associated with more severe and widespread neuropsychological deficits but fewer prior medical diagnoses than nondegenerative etiologies of cognitive impairment. AD and depression are common etiologies and the neuropsychological profiles are partly overlapping; however, memory, symptom awareness and global cognitive impairment measures may help in the differential diagnosis.

Determinants of Time to Diagnosis in Young-Onset Dementia

Timely diagnosis of young-onset dementia (YOD) is critical. This study aimed to identify factors that increased time to diagnosis at each stage of the diagnostic pathway. Participants were patients diagnosed with YOD (n = 40) and their care partners (n = 39). Information was obtained from questionnaires, and review of medical records. Mean time from symptom onset to YOD diagnosis was 3.6 ± 2 years. Suspicion of depression/anxiety at presentation was associated with significantly increased time from presentation to specialist referral. Neurologist-diagnosed YOD was the fastest route to a diagnosis, whereas diagnoses made by other specialists significantly increased the time from first specialist visit to diagnosis. By investigating multiple stages of the diagnostic pathway, we identified two factors that increased time to diagnosis: suspicion of depression/anxiety at presentation delayed specialist referral from primary care, and diagnosis by a specialist other than a neurologist delayed diagnosis of YOD.

Plasma neurofilament light in behavioural variant frontotemporal dementia compared to mood and psychotic disorders

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.

Diagnostic Instability Over Time in the Late-Onset Frontal Lobe Syndrome: When Can We Say it's FTD?

OBJECTIVES

Distinguishing sporadic behavioral variant of frontotemporal dementia (bvFTD) from late-onset primary psychiatric disorders (PPD) remains challenging with the lack of robust biomarkers. An early bvFTD misdiagnosis in PPD cases and vice-versa is common. Little is known about diagnostic (in)stability over longer period of time. We investigated diagnostic instability in a neuropsychiatric cohort up to 8 years after baseline visit and identified which clinical hallmarks contribute to diagnostic instability.

DESIGN

Diagnoses of participants of the late-onset frontal lobe (LOF) study were collected from the baseline visit (T0) and the 2-year follow-up visit (T2). Clinical outcomes were retrieved 5-8 years after baseline visit (Tfinal). Endpoint diagnoses were categorized into bvFTD, PPD and other neurological disorders (OND). We calculated the total amount of participants that switched diagnosis between T0-T2 and T2-Tfinal. Clinical records of participants that switched diagnosis were assessed.

RESULTS

Of the 137 patients that were included in the study, the final diagnoses at Tfinal were bvFTD 24.1% (n = 33), PPD 39.4% (n = 54), OND 33.6% (n = 46) and unknown 2.9% (n = 4). Between T0 and T2, a total of 29 (21.2%) patients switched diagnosis. Between T2 and Tfinal, 8 (5.8%) patients switched diagnosis. Prolonged follow-up identified few cases with diagnostic instability. Major contributors to diagnostic instability where a nonconverting diagnosis of possible bvFTD and a probable bvFTD diagnosis based on informant-based history and an abnormal FDG-PET scan whilst having a normal MRI.

CONCLUSION

Considering these lessons, a FTD diagnosis remains stable enough to conclude that 2 years is sufficient to say if a patient with late-life behavioral disorder has FTD.

Young-onset dementia diagnosis, management and care: a narrative review

Young-onset dementia comprises a heterogeneous range of dementias, with onset at less than 65 years of age. These include primary dementias such as Alzheimer disease, frontotemporal and vascular dementias; genetic/familial dementias; metabolic disorders; and secondary dementias such as those that result from alcohol use disorder, traumatic brain injury, and infections. The presentation of young-onset dementia is varied and may include cognitive, psychiatric and neurological symptoms. Diagnostic delay is common, with a frequent diagnostic conundrum being, "Is this young-onset dementia or is this psychiatric?". For assessment and accurate diagnosis, a thorough screen is recommended, such as collateral history and investigations such as neuroimaging, lumbar puncture, neuropsychology, and genetic testing. The management of young-onset dementia needs to be age-appropriate and multidisciplinary, with timely access to services and consideration of the family (including children).

Recent research advances in young-onset dementia

PURPOSE OF REVIEW

Young-onset dementia (YOD) refers to a dementia for which symptom onset occurs below the age of 65. This review summarizes the recent literature in this area, focusing on updates in epidemiology, diagnosis and service provision.

RECENT FINDINGS

In the last year, internationally, the prevalence of YOD was reported as 119 per 100 000, but this may vary according to population types. Although the commonest causes of YOD are Alzheimer's disease (AD) and frontotemporal dementia (FTD), there is increasing recognition that YOD is diagnostically and phenotypically broader than AD and FTD. YOD may be due to many other diseases (e.g. Huntington's disease, vascular dementia) whereas accumulation of the same protein (e.g. amyloid protein) may lead to different phenotypes of Alzheimer's disease (such as posterior cortical atrophy and behavioural-variant/frontal-variant AD). This heterogeneity of phenotypic presentation is also seen in YOD due to known genetic mutations. Biomarkers such as plasma and cerebrospinal fluid proteins, neuroimaging and genetics have shown promise in the early identification of YOD as well as providing further understanding behind the overlap between psychiatric and neurodegenerative conditions occurring in younger people. The management of YOD needs to consider age-specific issues for younger people with dementia and their family networks together with better integration with other health services such as aged, disability and improved access to services and financial assistance.

SUMMARY

These findings emphasize the need for early identification and appropriate age-specific and person-centred management for people with young-onset dementia.

Carer burden and psychological distress in young-onset dementia: An Australian perspective

OBJECTIVES

Carer burden in dementia is associated with poor outcomes, including early nursing home placement for people with dementia and psychological distress for their carers. Carers of people with young-onset dementia (YOD) are particularly vulnerable to carer burden. Yet they are often overlooked by clinicians as dementia services are generally designed for older people. We sought to estimate the rate of burden and psychological distress in carers of YOD at a state-wide tertiary service based in Australia.

METHODS

We conducted a cross-sectional study examining 71 dyads from a Neuropsychiatry service. We collected patient demographic and clinical data including the Neuropsychiatry Unit Cognitive Assessment tool (NUCOG) and Mini-Mental State Examination (MMSE). Carer data, such as demographics and psychological distress, were obtained using Depression Anxiety Stress Scale 21 (DASS-21). Carer burden was rated using the Zarit Burden Inventory-short version (ZBI).

RESULTS

Higher carer burden, measured using ZBI, was associated with longer duration of dementia and greater severity of overall cognitive impairment. Carers who felt burdened reported higher levels of stress, depression, and anxiety measured using DASS-21. Multiple linear regression analysis found carer burden was independently predicted by duration of dementia, total cognition score and carers experiencing psychological stress.

DISCUSSION

We found that patient variables of dementia duration and cognitive impairment and carer variable of carer stress to be associated with carer burden. Poor executive function was associated with carer stress. Early identification and management of carer burden and psychological distress is important for outcomes. Ideally, this should be provided by a specialist YOD service.

Music and Psychology & Social Connections Program: Protocol for a Novel Intervention for Dyads Affected by Younger-Onset Dementia

Psychosocial interventions targeting the specific needs of people affected by younger-onset dementia are lacking. Younger-onset dementia refers to dementia where symptom onset occurs at less than 65 years old. Because of its occurrence in middle age, the impact on spouses is particularly marked and dyadic-based interventions are recommended. Music And Psychology & Social Connections (MAPS) is a novel online intervention, informed by the theory of adaptive coping by Bannon et al. (2021) for dyads affected by younger-onset dementia. MAPS combines therapeutic songwriting, cognitive behaviour therapy, and a private social networking group that focuses on the dyads. This will be a randomised controlled trial with a waitlist control. The primary aims are to assess whether MAPS improves depressive, anxiety, and stress symptoms in caregivers, with secondary aims to assess whether MAPS improves depressive symptoms in people with younger-onset dementia. The trial also aims to assess dyadic social connectedness; caregiver coping skills; and neuropsychiatric symptoms in people with younger-onset dementia. We will recruit 60 dyads to participate in a group-based weekly online program for 8 weeks facilitated by a credentialed music therapist and psychologist. Sessions 1 and 8 will include both caregivers and people with younger-onset dementia and Sessions 2–7 will involve separate group sessions for caregivers and those with dementia. There will be focus groups for qualitative feedback. Due to its online administration, MAPS has the potential to reach many dyads affected by younger-onset dementia.

Bias Investigation in Artificial Intelligence Systems for Early Detection of Parkinson's Disease: A Narrative Review

Background and Motivation: Diagnosis of Parkinson's disease (PD) is often based on medical attention and clinical signs. It is subjective and does not have a good prognosis. Artificial Intelligence (AI) has played a promising role in the diagnosis of PD. However, it introduces bias due to lack of sample size, poor validation, clinical evaluation, and lack of big data configuration. The purpose of this study is to compute the risk of bias (RoB) automatically.

METHOD

The PRISMA search strategy was adopted to select the best 39 AI studies out of 85 PD studies closely associated with early diagnosis PD. The studies were used to compute 30 AI attributes (based on 6 AI clusters), using AP(ai)Bias 1.0 (AtheroPointTM, Roseville, CA, USA), and the mean aggregate score was computed. The studies were ranked and two cutoffs (Moderate-Low (ML) and High-Moderate (MH)) were determined to segregate the studies into three bins: low-, moderate-, and high-bias.

RESULT

The ML and HM cutoffs were 3.50 and 2.33, respectively, which constituted 7, 13, and 6 for low-, moderate-, and high-bias studies. The best and worst architectures were "deep learning with sketches as outcomes" and "machine learning with Electroencephalography," respectively. We recommend (i) the usage of power analysis in big data framework, (ii) that it must undergo scientific validation using unseen AI models, and (iii) that it should be taken towards clinical evaluation for reliability and stability tests.

CONCLUSION

The AI is a vital component for the diagnosis of early PD and the recommendations must be followed to lower the RoB.