Prevalence, characteristics, and survival of frontotemporal lobar degeneration syndromes

LATE-NC Stage 3: a diagnostic rubric to differentiate severe LATE-NC from FTLD-TDP

A diagnostic rubric is required to distinguish between limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC) and frontotemporal lobar degeneration with TDP-43 inclusions (FTLD-TDP). In LATE-NC Stage 3, TDP-43 proteinopathy is present in the middle frontal gyrus (MFG), thus posing a potential diagnostic challenge in differentiating these severe LATE-NC cases from FTLD-TDP. LATE-NC Stage 3 cases and other TDP-43 proteinopathies were analyzed from the University of Kentucky (total n = 514 with TDP-43 pathology assessed), The 90+ Study at the University of California Irvine (n = 458), and the Mayo Clinic (n = 5067) brain banks. Digital pathology was used to quantify pathology burden in a select subset of cases (n = 51), complemented by a previously-described manual counting method and expert neuropathologic examinations to evaluate qualitative features such as FTLD-TDP types and subtypes of neuronal cytoplasmic inclusions (NCIs). To evaluate clinical and genetic characteristics of LATE-NC Stage 3, data were analyzed from the National Alzheimer's Coordinating Center (NACC) Neuropathology Data set and correlated with findings from the Alzheimer's Disease Genetics Consortium (ADGC). When using TDP-43 proteinopathy quantification in the MFG as a diagnostic criterion, more than 90% of cases could be classified as either LATE-NC Stage 3 or FTLD-TDP. Diagnostically challenging scenarios included a subset of FTLD-TDP Type B cases with relatively mild MFG TDP-43 pathology and a novel non-LATE-NC, non-FTLD-TDP pathologic subtype with severe MFG TDP-43 pathology. Taking these potential pitfalls into account, a classification schema was developed that could correctly diagnose all included cases. There was no difference in the Alzheimer's disease pathological load in LATE-NC Stages 2 versus 3. In genetic analyses, the GRN (rs5848) risk allele was preferentially associated with LATE-NC Stage 3, whereas TMEM106B and APOE risk-associated variants were not. In conclusion, LATE-NC Stage 3 could be differentiated reliably from FTLD-TDP and other TDP-43-opathies, based on a data-driven diagnostic rubric.

Selective cellular and regional vulnerability in frontotemporal lobar degeneration: a scoping review

The three main types of frontotemporal lobar degeneration (FTLD) are characterized by the accumulation of abnormal proteins, namely tau, TDP-43 and FUS. The distribution of these proteins within different human brain regions is well known, as is the range of morphological variability of the cellular inclusions they form. Compared to the extensive knowledge that exists about distinct protein aggregates in FTLD, surprisingly little is known about the specific cell (sub)types that these inclusions affect. Even less is known about disease-specific abnormalities other than protein inclusions in affected and unaffected areas. These are non-trivial knowledge gaps. First, knowing which cell subtypes are vulnerable or resilient to the development of pathological protein inclusions is crucial to understand the cellular disease mechanisms. Second, mounting evidence suggests that non-cell autonomous mechanisms may play important roles in neurodegenerative conditions. For example, astrocytic tau pathology is associated with synaptic loss in corticobasal degeneration but not in progressive supranuclear palsy. Furthermore, changes that are more difficult and time-consuming to quantify, for example loss of a specific neuronal subtype that does not develop pathological inclusions, remain virtually unexplored and their relevance for disease progression are unknown. This scoping review is an attempt to collate all histological evidence from human studies that address the question of cell-specific vulnerability in the most common FTLD subtypes. By taking a systematic approach including various brain cell types such as neurons and their subtypes as well as astrocytes, microglia and oligodendrocytes and the entire central nervous system with its affected and unaffected regions, this review summarizes the current status in the field and highlights important knowledge gaps.

2024 VCP International Conference: Exploring multi-disciplinary approaches from basic science of valosin containing protein, an AAA+ ATPase protein, to the therapeutic advancement for VCP-associated multisystem proteinopathy

Valosin-containing protein (VCP/p97) is a ubiquitously expressed AAA+ ATPase associated with numerous protein-protein interactions and critical cellular functions including protein degradation and clearance, mitochondrial homeostasis, DNA repair and replication, cell cycle regulation, endoplasmic reticulum-associated degradation, and lysosomal functions including autophagy and apoptosis. Autosomal-dominant missense mutations in the VCP gene may result in VCP-associated multisystem proteinopathy (VCP-MSP), a rare degenerative disorder linked to heterogeneous phenotypes including inclusion body myopathy (IBM) with Paget's disease of bone (PDB) and frontotemporal dementia (FTD) or IBMPFD, amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), parkinsonism, Charcot-Marie Tooth disease (CMT), and spastic paraplegia. The complexity of VCP-MSP makes collaboration among stakeholders essential and necessitates a multi-disciplinary approach. The 2024 VCP International Conference was hosted at Caltech between February 22 and 25. Co-organized by Cure VCP Disease and Dr. Tsui-Fen Chou, the meeting aimed to center the patient as a research partner, harmonize diverse stakeholder engagement, and bridge the gap between basic and clinical neuroscience as it relates to VCP-MSP. Over 100 multi-disciplinary experts attended, ranging from basic scientists to clinicians to patient advocates. Attendees discussed genetics and clinical presentation, cellular and molecular mechanisms underlying disease, therapeutic approaches, and strategies for future VCP research. The conference included three roundtable discussions, 29 scientific presentations, 32 scientific posters, nine patient and caregiver posters, and a closing discussion forum. The following conference proceedings summarize these sessions, highlighting both the identified gaps in knowledge and the significant strides made towards understanding and treating VCP diseases.

My experience of person-centered and personalized care in early-stage primary progressive aphasia

Primary progressive aphasia (PPA) is a neurodegenerative brain disorder characterized by declining language ability. It is a rare, often young-onset dementia with a devastating impact on the work and personal activities of those affected. At present there is no cure or disease-modifying therapy for PPA nor any way to arrest or slow the underlying progressive brain degeneration. Throughout the course of the condition any treatment must therefore be palliative-designed to manage symptoms and improve the quality of life of the affected person. The majority of those affected receive little or no follow-up care after diagnosis, particularly in the early stage of the disease. There is very little information in the medical literature about person-centered care designed to improve the quality of life of people with PPA written from the perspective of those living with this condition. I received an early and accurate clinical diagnosis of the nonfluent/agrammatic variant of PPA, supported by imaging. I am fortunate to have benefited from exemplary individualized care from a multidisciplinary medical team from the onset of my difficulties with language. In this paper, I discuss my lived experience of all aspects of this personalized and person-centered care, describing how it was founded on shared decision-making and a holistic, dementia-inclusive approach encompassing the physical, mental, emotional, psychosocial and spiritual dimensions of living with an incurable neurodegenerative disease.

Alzheimer mimicry: LATE and PART

Alzheimer's disease (AD) is the main cause of dementia and accounts for 60% of dementia syndromes in people older than 75 years. The correct classification of AD and non-AD cases is mandatory to study disease mechanisms or new treatment possibilities. A typical clinical picture of AD consists of a progressive cognitive decline, with primary memory impairment. Structural, functional, and molecular brain imaging, along with CSF biomarkers of amyloid pathology, neurodegeneration, and the presence of a vulnerability-associated APOE genotype, support the diagnosis of AD. Use of biomarkers have led to the identification of individuals with mild cognitive impairment who are amyloid-negative addressing a conceptually separate clinical entity named suspected non-Alzheimer disease pathophysiology (SNAP). Clinical presentation and progression of SNAP can mimic AD which makes the final diagnosis and possible treatment uncertain in up to 30% of cases in clinical centers that are not using biomarkers. These non-AD pathologies are common with advancing age both in cognitively impaired and clinically normal elderly people and include Argyrophilic Grain Disease (ARG), Tangle Predominant Dementia and TDP-43 proteinopathy. The terms Primary age-related tauopathy (PART) and Limbic-dominant TDP-43 age-related encephalopathy (LATE) have been proposed as the most common and useful biological and emerging clinical construct to describe this phenomenon in > 80 years old individuals. Current evidence underlines the limitations of existing diagnostic tools, which remain inadequate for fully capturing the complexities of these conditions. Addressing these diagnostic ambiguities is crucial for assigning accurate diagnoses, reducing frequent misdiagnoses of AD, and implementing appropriate therapeutic strategies for elderly patients with mild cognitive impairment and dementia.

Exosomes as Biomarkers and Therapeutic Agents in Neurodegenerative Diseases: Current Insights and Future Directions

Neurodegenerative diseases (NDs) like Alzheimer's, Parkinson's, and ALS rank among the most challenging global health issues, marked by substantial obstacles in early diagnosis and effective treatment. Current diagnostic techniques frequently demonstrate inadequate sensitivity and specificity, whilst conventional treatment strategies encounter challenges related to restricted bioavailability and insufficient blood-brain barrier (BBB) permeability. Recently, exosomes-nanoscale vesicles packed with proteins, RNAs, and lipids-have emerged as promising agents with the potential to reshape diagnostic and therapeutic approaches to these diseases. Unlike conventional drug carriers, they naturally traverse the BBB and can deliver bioactive molecules to affected neural cells. Their molecular cargo can influence cell signaling, reduce neuroinflammation, and potentially slow neurodegenerative progression. Moreover, exosomes serve as non-invasive biomarkers, enabling early and precise diagnosis while allowing real-time disease monitoring. Additionally, engineered exosomes, loaded with therapeutic molecules, enhance this capability by targeting diseased neurons and overcoming conventional treatment barriers. By offering enhanced specificity, reduced immunogenicity, and an ability to bypass physiological limitations, exosome-based strategies present a transformative advantage over existing diagnostic and therapeutic approaches. This review examines the multifaceted role of exosomes in NDDs, emphasizing their diagnostic capabilities, intrinsic therapeutic functions, and transformative potential as advanced treatment vehicles.

Assessing Co-Localization of ITM2B With Alzheimer's Disease and Limbic-Predominant Age-Related TDP-43 Encephalopathy Neuropathologic Changes

Mutations in the Integral membrane protein 2B (ITM2B) gene are linked to the development of familial British and Danish dementias, two relatively early-onset dementia disorders known also to be associated with Tau neurofibrillary tangles (NFTs). However, to date, the involvement of ITM2B in limbic-predominant age-related TDP-43 encephalopathy neuropathologic changes (LATE-NC) remains unclear. To address this question, we used brain samples from the University of Kentucky Alzheimer's Disease Research Center community-based autopsy cohort. We investigated the patterns and co-localizations of ITM2B immunohistochemistry in subiculum, CA1, CA2, CA3 and dentate gyrus of the hippocampus from brains with Alzheimer's disease neuropathologic changes (ADNC), LATE-NC, and comorbid ADNC+LATE-NC, as well as low-pathology controls (n = 4 per disease state). There was frequent co-localization between ITM2B protein and intracellular Tau pathology in ADNC; however, there was a far weaker rate of co-localization between ITM2B and TDP-43 pathology. There also was, as previously described, an association between ITM2B immunostaining and neuritic-appearing amyloid plaques. Additionally, co-localization of intracellular ITM2B pathology with Thioflavin-S in NFTs suggested a potential role for ITM2B in marking neurons undergoing transition from relatively healthy (early NFT-bearing cells) to more severely affected (later NFT-bearing) cellular disease states. This study indicates that ITM2B has a relatively specific pattern of involvement in Tau-related neurodegeneration and in neuritic amyloid plaques, while implying minimal, if any, role for ITM2B in the synergistic relationship between Tau and TDP-43 pathologies.

Behavioral and neural effects of temporoparietal high-definition transcranial direct current stimulation in logopenic variant primary progressive aphasia: a preliminary study

Background

High-definition-tDCS (HD-tDCS) is a recent technology that allows for localized cortical stimulation, but has not yet been investigated as an augmentative therapy while targeting the left temporoparietal cortex in logopenic variant PPA (lvPPA). The changes in neuronal oscillatory patterns and resting-state functional connectivity in response to HD-tDCS also remains poorly understood.

Objective

We sought to investigate the effects of HD-tDCS with phonologic-based language training on language, cognition, and resting-state functional connectivity in lvPPA.

Methods

We used a double-blind, within-subject, sham-controlled crossover design with a 4-month between-treatment period in four participants with lvPPA. Participants completed language, cognitive assessments, and imaging with magnetoencephalography (MEG) and resting-state functional MRI (fMRI) prior to treatment with either anodal HD-tDCS or sham targeting the left supramarginal gyrus over 10 sessions. Language and cognitive assessments, MEG, and fMRI were repeated after the final session and at 2 months follow-up. Preliminary data on efficacy was evaluated based on relative changes from baseline in language and cognitive scores. Language measures included metrics derived from spontaneous speech from picture description. Changes in resting-state functional connectivity within the phonological network were analyzed using fMRI. Magnitudes of source-level evoked responses and hemispheric laterality indices from language task-based MEG were used to assess changes in cortical engagement induced by HD-tDCS.

Results

All four participants were retained across the 4-month between-treatment period, with satisfactory blinding of participants and investigators throughout the study. Anodal HD-tDCS was well tolerated with a side effect profile that did not extend past the immediate treatment period. No benefit of HD-tDCS over sham on language and cognitive measures was observed in this small sample. Functional imaging results using MEG and fMRI indicated an excitatory effect of anodal HD-tDCS compared to sham and suggested that greater temporoparietal activation and connectivity was positively associated with language outcomes.

Conclusion

Anodal HD-tDCS to the inferior parietal cortex combined with language training appears feasible and well tolerated in participants with lvPPA. Language outcomes may be explained by regression to the mean, and to a lesser degree, by ceiling effects and differences in baseline disease severity. The intervention has apparent temporoparietal correlates, and its clinical efficacy should be further studied in larger trials.

Clinical trial registration

ClinicalTrials.gov, Number NCT03805659.

Distinct spatiotemporal atrophy patterns in corticobasal syndrome are associated with different underlying pathologies

Although the corticobasal syndrome was originally most closely linked with the pathology of corticobasal degeneration, the 2013 Armstrong clinical diagnostic criteria, without the addition of aetiology-specific biomarkers, have limited positive predictive value for identifying corticobasal degeneration pathology in life. Autopsy studies demonstrate considerable pathological heterogeneity in corticobasal syndrome, with corticobasal degeneration pathology accounting for only ∼50% of clinically diagnosed individuals. Individualized disease stage and progression modelling of brain changes in corticobasal syndrome may have utility in predicting this underlying pathological heterogeneity, and in turn improve the design of clinical trials for emerging disease-modifying therapies. The aim of this study was to jointly model the phenotypic and temporal heterogeneity of corticobasal syndrome, to identify unique imaging subtypes based solely on a data-driven assessment of MRI atrophy patterns and then investigate whether these subtypes provide information on the underlying pathology. We applied Subtype and Stage Inference, a machine learning algorithm that identifies groups of individuals with distinct biomarker progression patterns, to a large cohort of 135 individuals with corticobasal syndrome (52 had a pathological or biomarker defined diagnosis) and 252 controls. The model was fit using volumetric features extracted from baseline T1-weighted MRI scans and then used to subtype and stage follow-up scans. The subtypes and stages at follow-up were used to validate the longitudinal consistency of the baseline subtype and stage assignments. We then investigated whether there were differences in associated pathology and clinical phenotype between the subtypes. Subtype and Stage Inference identified at least two distinct and longitudinally stable spatiotemporal subtypes of atrophy progression in corticobasal syndrome; four-repeat-tauopathy confirmed cases were most commonly assigned to the Subcortical subtype (83% of individuals with progressive supranuclear palsy pathology and 75% of individuals with corticobasal-degeneration pathology), whilst those with Alzheimer's pathology were most commonly assigned to the Fronto-parieto-occipital subtype (81% of individuals). Subtype assignment was stable at follow-up (98% of cases), and individuals consistently progressed to higher stages (100% stayed at the same stage or progressed), supporting the model's ability to stage progression. By jointly modelling disease stage and subtype, we provide data-driven evidence for at least two distinct and longitudinally stable spatiotemporal subtypes of atrophy in corticobasal syndrome that are associated with different underlying pathologies. In the absence of sensitive and specific biomarkers, accurately subtyping and staging individuals with corticobasal syndrome at baseline has important implications for screening on entry into clinical trials, as well as for tracking disease progression.

Frontotemporal dementia. How to deal with its diagnostic complexity?

INTRODUCTION

Frontotemporal dementia (FTD) encompasses a group of heterogeneous neurodegenerative disorders. Aside from genetic cases, its diagnosis is challenging, particularly in the early stages when symptoms are ambiguous, and structural neuroimaging does not reveal characteristic patterns.

AREAS COVERED

The authors performed a comprehensive literature search through MEDLINE, Scopus, and Web of Science databases to gather evidence to aid the diagnostic process for suspected FTD patients, particularly in early phases, even in sporadic cases, ranging from established to promising tools. Blood-based biomarkers might help identify very early neuropathological stages and guide further evaluations. Subsequently, neurophysiological measures reflecting functional changes in cortical excitatory/inhibitory circuits, along with functional neuroimaging assessing brain network, connectivity, metabolism, and perfusion alterations, could detect specific changes associated to FTD even decades before symptom onset. As the neuropathological process advances, cognitive-behavioral profiles and atrophy patterns emerge, distinguishing specific FTD subtypes.

EXPERT OPINION

Emerging disease-modifying therapies require early patient enrollment. Therefore, a diagnostic paradigm shift is needed - from relying on typical cognitive and neuroimaging profiles of advanced cases to widely applicable biomarkers, primarily fluid biomarkers, and, subsequently, neurophysiological and functional neuroimaging biomarkers where appropriate. Additionally, exploring subjective complaints and behavioral changes detected by home-based technologies might be crucial for early diagnosis.

Noninvasive Brain Stimulation in Primary Progressive Aphasia with and Without Concomitant Speech and Language Therapy: Systematic Review and Meta-analysis

Primary progressive aphasias (PPA) represent a group of neurodegenerative conditions affecting verbal communication abilities for which no effective medication is currently available. Noninvasive brain stimulation (NiBS) has been mainly explored as adjunctive therapy to conventional speech and language therapy (SLT) with promising results. The present meta-analysis of randomized-controlled trials (RCTs) aims to evaluate the efficacy of NiBS in PPA patients on a range of linguistic tasks (naming, phonemic fluency, semantic fluency). A literature search was carried out using EMBASE and PUBMED, searching for multi-session RCTs administering NiBS on PPA patients as stand-alone or with SLT. The results were not significant overall, indicating a null difference between the active and the sham condition on language functions; pooled effects tended to be higher in parallel than in crossover studies and for follow-ups than post-treatment. In the naming analyses, the combined effects for the studies that coupled NiBS with SLT were slightly higher than the overall effect at each time point, although not significant. These results need to be considered with caution given the low number of included studies and small sample sizes, but offer relevant indications for future research in terms of optimal treatment protocols and personalization of therapies.

Predicting survival rate by plasma biomarkers and clinical variables in syndromes associated with frontotemporal lobar degeneration

INTRODUCTION

Modeling the survival rate in syndromes associated with frontotemporal lobar degeneration (FTLD) is essential to assess disease trajectories.

METHODS

In 262 patients with FTLD, we considered plasma neurofilament light chain (NfL), glial fibrillary acidic protein, brain-derived tau, phosphorylated tau217 and amyloid beta (Aβ42/Aβ40). The FTLD Survival Score (FTLD-SS) was calculated by the β coefficients of the variables independently associated with survival rate.

RESULTS

Increased plasma NfL levels (p < 0.001), older age at evaluation (p = 0.002), positive family history (p = 0.04), and motor phenotypes (p < 0.001) were associated with reduced survival. The predictive validity of FTLD-SS was 0.75 (95% confidence interval, 0.59-0.91) at 1 year.

DISCUSSION

Survival rate in FTLD is shaped by intensity of neurodegeneration (using plasma NfL as proxy) together with certain clinical variables. The FTLD-SS may serve as a simple tool for survival rate estimation and for patient stratification in clinical trials.

HIGHLIGHTS

Plasma neurofilament light chain and clinical variables can predict survival in frontotemporal lobar degeneration (FTLD)-associated syndromes. FTLD Survival Score (FTLD-SS), computed with survival predictors, may serve as a simple tool for patient stratification. FTLD-SS is associated with greater atrophy in frontal and putamen areas.

MRI classification of progressive supranuclear palsy, Parkinson disease and controls using deep learning and machine learning algorithms for the identification of regions and tracts of interest as potential biomarkers

BACKGROUND

Quantitative magnetic resonance imaging (MRI) analysis has shown promise in differentiating neurodegenerative Parkinsonian syndromes and has significantly advanced our understanding of diseases like progressive supranuclear palsy (PSP) in recent years.

OBJECTIVE

The aim of this study was to develop, implement and compare MRI analysis algorithms based on artificial intelligence (AI) that can differentiate PSP not only from healthy controls but also from Parkinson disease (PD), by analyzing changes in brain structure and microstructure. Specifically, this study focused on identifying regions of interest (ROIs) and tracts of interest (TOIs) that are crucial for the algorithms to provide clinically relevant performance indices for the distinction between disease variants.

METHODS

MR data comprised diffusion tensor imaging (DTI - tractwise fractional anisotropy statistics (TFAS)) and T1-weighted (T1-w) data (texture analysis of the corpus callosum (CC)). One subject sample with 74 PSP patients and 63 controls was recorded at 3.0T at multiple sites. The other sample came from a single site, consisting of 66 PSP patients, 66 PD patients, and 44 controls, recorded at 1.5T. Four different machine learning algorithms (ML) and a deep learning (DL) neural network approach using Tensor Flow were implemented for the study. The training of the algorithms was performed on 80 % of the data, which included the entire single-site data and parts of the multiple-site data. The validation process was conducted on the remaining data, thereby consistently separating training and validation data.

RESULTS

A random forest algorithm and a DL neural network classified PSP and healthy controls with accuracies of 92 % and 95 %, respectively. Particularly, DTI derived measures for the pons, midbrain tegmentum, superior cerebral peduncle, putamen, and CC contributed to high accuracies. Furthermore, DL neural network classification of PSP and PD with 86 % accuracy showed the importance of 19 structures. The four most important features were DTI derived measures for prefrontal white matter, the fasciculus frontooccipitalis, the midbrain tegmentum, and the CC area II. This DL network achieved a sensitivity of 88 % and specificity of 85 %, resulting in a Youden-index of 0.72.

CONCLUSION

The primary goal of the present study was to compare multiple ML-methods and a DL approach to identify the least necessary set of brain structures to classify PSP vs. controls and PSP vs. PD by ranking them in a hierarchical order of importance. That way, this study demonstrated the potential of AI approaches to MRI as possible diagnostic and scientific tools to differentiate variants of neurodegenerative Parkinsonism.

Post mortem validation and mechanistic study of UCB-J in progressive supranuclear palsy patients' brains

INTRODUCTION

Progressive supranuclear palsy (PSP) is a devastating 4R tauopathy affecting motor functions and is often misdiagnosed/underdiagnosed due to a lack of specific biomarkers. Synaptic loss is an eminent feature of tauopathies including PSP. Novel synaptic positron emission tomography tracer UCB-J holds great potential for early diagnosis; however, there is a substantial knowledge gap in terms of the mechanism and the extent and nature of synaptic loss in PSP.

METHODS

Here, we report an in-depth post mortem validation and mechanistic study of UCB-J in PSP and control brains using radioligand/autoradiography binding studies, alongside biochemical correlation analyses of synaptic markers.

RESULTS AND DISCUSSION

3H-UCB-J targeted synaptic vesicle protein 2A protein with high specificity and demonstrated a distinct interrelation with synaptic markers in PSP patients' brain regions. The loss of UCB-J binding in the early and severely affected globus pallidus of PSP patients' brains revealed deficits of glutamate/GABAergic synaptic terminals. Cortical and subcortical 4R tau load differentially impacted synaptic marker profiles across PSP patients, warranting further investigation.

HIGHLIGHTS

UCB-J targeted synaptic vesicle protein 2A with high specificity in progressive supranuclear palsy (PSP) brains and demonstrated a conserved single nM binding site across different brain regions. UCB-J depicted prominent synaptic loss at the synaptosome levels and revealed deficits of glutamate/GABAergic synaptic terminals in the early affected globus pallidus of PSP brains as compared to the control. Cortical and subcortical 4R tau load distinctly influenced synaptic markers profile across PSP patients and highlighted that presynaptic "ubiquitous" markers individually might not be able to represent the complete state of synaptic deficits/loss in PSP brains.

[Clinical guidelines «Cognitive disorders in the elderly and senile persons»]

Clinical guidelines «Cognitive disorders in the elderly and senile persons».

New criteria to predict LATE-NC in the clinical setting: Probable/Possible LATE and LANS

This review discusses terminology recently proposed for the classification of dementia and, more specifically, nosology related to aging-associated TDP-43 pathology: limbic-predominant age-related TDP-43 encephalopathy (LATE), and limbic-predominant amnestic neurodegenerative syndrome (LANS). While the "gold standard" for these clinical conditions is still LATE neuropathologic changes (LATE-NC), clinical criteria and biomarkers are evolving. The newly proposed clinical rubrics are discussed with emphasis on the need for terminology that acknowledges the distinctions between clinical syndrome-, molecular biomarker-, and pathologically defined disease concepts. As further progress is made on research into the specific biomarker-based detection and prediction of TDP-43 proteinopathy in the clinical setting, the definitions of "Probable" and "Possible" LATE are likely to become more useful clinically. For people interested in the pathological diagnoses or basic research related to LATE-NC, the relevant terminology remains unchanged by the newly proposed clinical criteria.

Caregiver perspectives enable accurate diagnosis of neurodegenerative disease

BACKGROUND

The history from a relative or caregiver is an important tool for differentiating neurodegenerative disease. We characterized patterns of caregiver questionnaire responses, at diagnosis and follow-up, on the Cambridge Behavioural Inventory (CBI).

METHODS

Data-driven multivariate analysis (n = 4952 questionnaires) was undertaken for participants (n = 2481) with Alzheimer's disease (typical/amnestic n = 543, language n = 50, and posterior cortical n = 50 presentations), Parkinson's disease (n = 740), dementia with Lewy bodies (n = 55), multiple system atrophy (n = 55), progressive supranuclear palsy (n = 422), corticobasal syndrome (n = 176), behavioral variant frontotemporal dementia (n = 218), semantic (n = 125) and non-fluent variant progressive aphasia (n = 88), and motor neuron disease (n = 12).

RESULTS

Item-level support vector machine learning gave high diagnostic accuracy between diseases (area under the curve mean 0.83), despite transdiagnostic changes in memory, behavior, and everyday function. There was progression in CBI subscores over time, which varied by diagnosis.

DISCUSSION

Our results highlight the differential diagnostic information for a wide range of neurodegenerative diseases contained in a simple, structured collateral history.

HIGHLIGHTS

We analyzed 4952 questionnaires from caregivers of 2481 participants with neurodegenerative disease. Behavioral and neuropsychiatric manifestations of neurodegenerative disease had overlapping diagnostic boundaries. Simple questionnaire response patterns were sufficient for accurate diagnosis of each disease. We reinforce the value of a collateral history to support a diagnosis of dementia. The Cambridge Behavioural Inventory is sensitive to change over time and suitable as an outcome measure in clinical trials.

Primary Progressive Aphasia in Italian and English: A Cross-Linguistic Cohort Study

BACKGROUND AND OBJECTIVES

Current formulations of primary progressive aphasia (PPA) derive largely from English-speaking patients. We hypothesized that language-specific characteristics influence PPA phenotypes in 2 contrasting languages: Italian and English.

METHODS

We undertook a retrospective, cross-sectional, observational comparison of 2 patient cohorts representing all major PPA syndromes, in London and Florence. Neuropsychological scores in a range of linguistic and general cognitive domains were normalized to native speaker controls and dichotomized as impaired/unimpaired. Proportions were compared using χ2 tests and adjusted for symptom duration and severity of cognitive impairment using logistic regression.

RESULTS

The cohorts comprised 106 (48.1% female) Italian speakers (14 nonfluent/agrammatic [nfvPPA], 20 semantic [svPPA], 41 logopenic variant [lvPPA], 31 mixed PPA [mPPA]) and 166 (45.2% female) English speakers (70 nfvPPA, 45 svPPA, 42 lvPPA, 9 mPPA). Comparing cohorts, the English cohort was younger (mean 62.7 [SD = 8.4] vs 65.9 [7.8] years; p = 0.003, Cohen d = 0.39), with longer symptom duration (4.6 [4.3] vs 3.1 [2.5] years; p = 0.048, d = 1.08), a higher proportion of nfvPPA cases (42% vs 13%, χ2 = 25.4, p < 0.001), and lower proportions of lvPPA (25% vs 38%, χ2 = 5.46, p = 0.019) and mPPA (5% vs 29%, χ2 = 29.3, p < 0.001). English-speaking nfvPPA patients had less frequent expressive agrammatism (46% vs 93%, p = 0.015, odds ratio [OR] 16.05, 95% CI 1.70-151.13) but more frequently impaired single-word comprehension (60% vs 8%, p = 0.013, OR 0.06, 95% CI 0.00-0.56). English svPPA patients had more frequent surface dyslexia (68% vs 30%, p = 0.046, OR 0.24, 95% CI 0.06-0.97) and dysgraphia (38% vs 10%, p = 0.021, OR 0.09, 95% CI 0.01-0.70) while English lvPPA patients had more frequently impaired single-word comprehension (89% vs 29%, p < 0.001, OR 0.05, 95% CI 0.01-0.28), word repetition (61% vs 26%, p = 0.020, OR 0.24, 95% CI 0.07-0.80), nonword repetition (78% vs 30%, p = 0.010, OR 0.18, 95% CI 0.05-0.06), nonverbal working memory (69% vs 36%, p = 0.005, OR 0.10, 95% CI 0.02-0.51), and visuomotor function (89% vs 25%, p < 0.001, OR 0.02, 95% CI 0.01-0.20).

DISCUSSION

Language-specific characteristics influenced PPA phenotypes, with more frequent expressive agrammatism in Italian (reflecting its morphologic complexity), more frequently impaired word processing in English (reflecting its articulatory, acoustic, and orthographic complexity), and increased prevalence of mPPA in Italian. These findings have implications for PPA diagnosis and management. Limitations of test heterogeneity and cohort size should be addressed in future, prospective, multicenter initiatives using cross-linguistic tools.

Statistical examination of shared loci in neuropsychiatric diseases using genome-wide association study summary statistics

Continued methodological advances have enabled numerous statistical approaches for the analysis of summary statistics from genome-wide association studies. Genetic correlation analysis within specific regions enables a new strategy for identifying pleiotropy. Genomic regions with significant 'local' genetic correlations can be investigated further using state-of-the-art methodologies for statistical fine-mapping and variant colocalisation. We explored the utility of a genome-wide local genetic correlation analysis approach for identifying genetic overlaps between the candidate neuropsychiatric disorders, Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), frontotemporal dementia, Parkinson's disease, and schizophrenia. The correlation analysis identified several associations between traits, the majority of which were loci in the human leukocyte antigen region. Colocalisation analysis suggested that disease-implicated variants in these loci often differ between traits and, in one locus, indicated a shared causal variant between ALS and AD. Our study identified candidate loci that might play a role in multiple neuropsychiatric diseases and suggested the role of distinct mechanisms across diseases despite shared loci. The fine-mapping and colocalisation analysis protocol designed for this study has been implemented in a flexible analysis pipeline that produces HTML reports and is available at: https://github.com/ThomasPSpargo/COLOC-reporter.

Comparing high definition transcranial direct current stimulation to left temporoparietal junction and left inferior frontal gyrus for logopenic primary progressive aphasia: A single-case study

Logopenic variant primary progressive aphasia (lvPPA) is characterized by word-finding deficits and phonologic errors in fluent speech. Transcranial direct current stimulation (tDCS) targeting either left temporoparietal junction (TPJ) or left inferior frontal gyrus (IFG) show evidence of improving language function in lvPPA. The present case study evaluated the effects of two separate rounds of high definition tDCS (HD-tDCS) (4 mA; 30 sessions) on language and functional neuroimaging in a 57-year-old woman with lvPPA. Stimulation was centred on two different regions across rounds: (1) left TPJ, and (2) left (IFG). Results showed an improved proportion of content to floorholder words during a naturalistic speech task through both rounds as well as change in confrontation naming after TPJ (improvement) and IFG (worsened) stimulation. fMRI connectivity during task showed left lateralized positive correlations following round 1 and anti-correlations with components of the default mode network following round 2. Resting state segregation of a language-associated functional network increased following both rounds, and task-based segregation of the same network increased following IFG stimulation. These results suggest that stimulation to both regions using HD-tDCS may improve language function in lvPPA, while simultaneously eliciting widespread changes beyond the targeted area in neuronal activity and functional connectivity.

Altered neurovascular coupling in semantic variant primary progressive aphasia

BACKGROUND

Semantic variant primary progressive aphasia (svPPA) is one of the main clinical phenotypes of frontotemporal lobar degeneration. Changes in both neuronal activity and cerebral perfusion have been observed in svPPA, suggesting a possible breakdown of neurovascular coupling (NVC).

OBJECTIVE

To investigate alterations in NVC and their correlations with clinical manifestations in svPPA patients.

METHODS

In this study, a cohort consisting of 19 subjects diagnosed with svPPA and 36 cognitively unimpaired controls (CUCs) have been enrolled for analysis. All participants underwent multimodal magnetic resonance imaging (MRI) scans, resting-state functional MRI and arterial spin labelling, and neuropsychological assessments. The amplitude of low-frequency fluctuations (ALFF) and cerebral blood flow (CBF) were obtained to measure neural activity and perfusion, respectively. The calculation of voxel CBF-ALFF correlation and CBF/ALFF ratio enables the assessment of global NVC and regional NVC, respectively. Correlations between the CBF/ALFF ratios and cognitive scores of the svPPA patients were analyzed. The relationships between the CBF/ALFF ratios and the cognitive performance of the svPPA patients were investigated through correlational analyses.

RESULTS

Compared with CUCs, svPPA patients had decreased global CBF-ALFF correlation coefficients (p < 0.001) and lower CBF/ALFF ratios in bilateral inferior temporal gyrus, fusiform gyrus, left temporal pole and middle temporal gyrus (p < 0.05). In svPPA patients, the CBF/ALFF ratios in the left inferior and middle temporal gyrus correlated positively with naming ability and general cognition, respectively.

CONCLUSIONS

The study indicate that NVC is disrupted in svPPA patients and is relevant to cognitive and language function.

Quality of life in patients with progressive supranuclear palsy: a review of literature and implications for practice

Progressive supranuclear palsy (PSP) is an atypical form of parkinsonism characterized by tauopathy, manifesting as oculomotor dysfunction, postural instability, akinesia, and cognitive/language impairments. The diagnosis and examination of PSP can be challenging, primarily due to the unclear and underexplored pathomechanisms involved, alongside absence of effective treatments. Clinical variants of PSP is the second most common form of neurodegenerative parkinsonism after Parkinson's disease (PD). It is defined by a symmetrical akinetic-rigid syndrome (atypical parkinsonism) and vertical supranuclear gaze palsy. In contrast to PD, PSP often presents with gait instability, backward falls, and cognitive and behavioral changes at early disease stages. The classification of PSP has evolved since Richardson, Steele, and Olszewski's initial reporting of the condition in 1963, which included a cohort of nine patients. Over the years, the definition of this disorder has evolved to encapsulate a group of patients with distinct clinical variants, notably the classical Richardson syndrome (RS) and several atypical phenotypes, each with significant implications for disease progression and quality of life (QoL). The 2017 Movement Disorder Society Diagnostic Criteria by Hoglinger et al., improved the sensitivity for detecting early and variant PSP presentations and provided more specific differential diagnoses for conditions such as PD and other forms of atypical parkinsonian syndromes. Owing to the growing interest in the disease's progression, evaluating the QoL for patients with PSP has become crucial. This review emphasizes the significance of QoL evaluation and its feasibility for practical implications, serving as an initial foundation for future research focused on the well-being of individuals affected by PSP. Progressive supranuclear palsy (PSP) is an atypical form of parkinsonism characterized by tauopathy, manifesting as oculomotor dysfunction, postural instability, akinesia, and cognitive/language impairments. Diagnosing PSP is challenging owing to the lack of tools for differential examination. Additionally, the pathomechanism of this disease is not sufficiently understood, and no treatment is currently available. Owing to the growing interest in the disease's progression, evaluating the quality of life (QoL) for patients with PSP has become crucial. This review emphasizes the significance of QoL evaluation and its feasibility for practical implications, serving as an initial foundation for future research focused on the well-being of individuals affected by PSP.

Pure LATE-NC: Frequency, clinical impact, and the importance of considering APOE genotype when assessing this and other subtypes of non-Alzheimer's pathologies

Pure limbic-predominant age-related TDP-43 encephalopathy neuropathologic changes (pure LATE-NC) is a term used to describe brains with LATE-NC but lacking intermediate or severe levels of Alzheimer's disease neuropathologic changes (ADNC). Focusing on pure LATE-NC, we analyzed data from the National Alzheimer's Coordinating Center (NACC) Neuropathology Data Set, comprising clinical and pathological information aggregated from 32 NIH-funded Alzheimer's Disease Research Centers (ADRCs). After excluding subjects dying with unusual conditions, n = 1,926 autopsied subjects were included in the analyses. For > 90% of these participants, apolipoprotein E (APOE) allele status was known; 46.5% had at least one APOE 4 allele. In most human populations, only 15-25% of people are APOE ε4 carriers. ADRCs with higher documented AD risk allele (APOE or BIN1) rates had fewer participants lacking ADNC, and correspondingly low rates of pure LATE-NC. Among APOE ε4 non-carries, 5.3% had pure LATE-NC, 37.0% had pure ADNC, and 3.6% had pure neocortical Lewy body pathology. In terms of clinical impact, participants with pure LATE-NC tended to die after having received a diagnosis of dementia: 56% died with dementia among APOE ε4 non-carrier participants, comparable to 61% with pure ADNC. LATE-NC was associated with increased Clinical Dementia Rating Sum of Boxes (CDR-SOB) scores, i.e. worsened global cognitive impairments, in participants with no/low ADNC and no neocortical Lewy body pathology (p = 0.0023). Among pure LATE-NC cases, there was a trend for higher LATE-NC stages to be associated with worse CDR-SOB scores (p = 0.026 for linear trend of LATE-NC stages). Pure LATE-NC was not associated with clinical features of disinhibition or primary progressive aphasia. In summary, LATE-NC with no or low levels of ADNC was less frequent than pure ADNC but was not rare, particularly among individuals who lacked the APOE 4 allele, and in study cohorts with APOE 4 frequencies similar to those in most human populations.

Dysphagia in progressive supranuclear palsy: A scoping review

Introduction

One of the most prevalent types of atypical parkinsonian syndrome is progressive supranuclear palsy (PSP). PSP is associated with early onset of dysphagia which can result in malnutrition, dehydration, and aspiration pneumonia, affecting quality of life and increasing mortality rate. To date, research describing dysphagia in PSP and its impact is scant.

Methods

The objective of this scoping review is to determine the characteristics of dysphagia in PSP, differences in dysphagia presentation according to PSP subtype, principal methods used for identifying and diagnosing dysphagia and the impact dysphagia has on quality of life in individuals with PSP. This review was conducted in accordance with the JBI methodology. Six electronic databases were searched.

Results

Of the 20 studies included, the most frequently reported characteristics of dysphagia were oral preparatory and oral phase difficulties. A variety of methods were used to identify and diagnose dysphagia including instrumental assessment (65%), patient reported scales (45%) and clinical swallow evaluation (20%). The most used instrumental assessment was videofluoroscopy (46%). Limited data was available describing characteristics of dysphagia according to the subtype of PSP. The impact that dysphagia has on quality of life was assessed in only one study.

Conclusion

A range of assessment methods are used to identify and diagnose dysphagia in patients with PSP. Further research is needed to investigate if particular characteristics are associated with certain PSP subtypes. Future studies should also measure the impact that dysphagia has on quality of life in this population.

A framework for translating tauopathy therapeutics: Drug discovery to clinical trials

The tauopathies are defined by pathological tau protein aggregates within a spectrum of clinically heterogeneous neurodegenerative diseases. The primary tauopathies meet the definition of rare diseases in the United States. There is no approved treatment for primary tauopathies. In this context, designing the most efficient development programs to translate promising targets and treatments from preclinical studies to early-phase clinical trials is vital. In September 2022, the Rainwater Charitable Foundation convened an international expert workshop focused on the translation of tauopathy therapeutics through early-phase trials. Our report on the workshop recommends a framework for principled drug development and a companion lexicon to facilitate communication focusing on reproducibility and achieving common elements. Topics include the selection of targets, drugs, biomarkers, participants, and study designs. The maturation of pharmacodynamic biomarkers to demonstrate target engagement and surrogate disease biomarkers is a crucial unmet need. HIGHLIGHTS: Experts provided a framework to translate therapeutics (discovery to clinical trials). Experts focused on the "5 Rights" (target, drug, biomarker, participants, trial). Current research on frontotemporal degeneration, progressive supranuclear palsy, and corticobasal syndrome therapeutics includes 32 trials (37% on biologics) Tau therapeutics are being tested in Alzheimer's disease; primary tauopathies have a large unmet need.

Clinical prognostic factors in progressive supranuclear palsy: Implications for clinical trials

BACKGROUND

Progressive supranuclear palsy (PSP) is a rare neurodegenerative disease with diverse clinical phenotypes, prompting the development of new diagnostic criteria known as the MDS-PSP classification. However, little is known about the prognostic value of this classification in order to better stratify patients for the clinical trials.

OBJECTIVE

To assess the impact of the different clinical phenotypes according to the MDS-PSP classification on prognosis using the clinical milestones of death, severe dysphagia, institutionalization, and need for walking aid.

METHODS

A prospective cohort of 205 PSP patients from Lille University Hospital was analyzed retrospectively. Patients were classified into different MSD-PSP phenotypes according to their clinical presentation after 3 years of follow-up. The milestones of death, severe dysphagia, institutionalization, and need for walking aid were recorded, and a survival analysis was performed to describe the prognosis of each disease presentation.

RESULTS

Median survival time was 6.4 (interquartile range (IQR): 4.8-8.6) years and mean diagnostic delay from symptom onset was 38.1 ± 22.5 months. PSP Richardson Syndrome (PSP-RS) had a poorer survival rate and a higher occurrence of severe dysphagia and need for walking aid compared to PSP variants such as PSP Parkinsonism (PSP-P), PSP postural instability without ocular motor dysfunction (PSP-PI), and other rare phenotypes.

CONCLUSIONS

PSP-RS has a less favorable prognosis compared to PSP variants stratified according to the MDS-PSP classification. This classification could assist in selecting patients for clinical trials and help design outcomes that account for the disease heterogeneity.

Regional cerebral blood flow in behavioral variant of FTD: hypoperfusion patterns and clinical associations

BACKGROUND

Findings from functional neuroimaging techniques, such as single-photon emission computed tomography (SPECT), may add useful evidence improving Frontotemporal Dementia (FTD) diagnosis. The aim of the present study was to investigate patterns of hypoperfusion in a group of patients diagnosed with the behavioral variant of FTD (bvFTD) and to explore the relationship between brain perfusion and clinical characteristics.

MATERIALS AND METHODS

Brain perfusion of 23 bvFTD patients was measured with SPECT scintigraphy in lobes and Brodmann areas (BAs) and the NeurogamTM software was used for image analysis. To assess behavioral disturbances and dementia severity, patients' informants completed the Frontotempotal Behavioral Inventory and the Frontotemporal Dementia Rating Scale. Descriptive statistics were used for the detection of pathological hypoperfusion in lobes and selected BAs. Associations among patients' clinical characteristics and perfusion in lobes were explored via non-parametric correlations.

RESULTS

Participants presented pathological hypoperfusion in frontal, limbic and temporal lobes. The most prominent deficit was observed in limbic lobes, where all participants showed pathological hypoperfusion. Decreased perfusion was also observed in limbic, frontal and temporal BAs. Perfusion in the left and right frontal lobe was associated with behavioral disturbances and disease severity, which was also correlated with perfusion in right limbic, left and right temporal areas.

CONCLUSION

Patterns of limbic, frontal and temporal hypopefusion were reported in the present study, along with associations between brain perfusion, behavioral disturbance and severity of dementia. Perfusion patterns can help to understand further associated brain biomarkers, contributing to early diagnosis and intervention in bvFTD.

Frequency and Longitudinal Course of Behavioral and Neuropsychiatric Symptoms in Participants With Genetic Frontotemporal Dementia

BACKGROUND AND OBJECTIVES

Behavioral and neuropsychiatric symptoms are frequent in patients with genetic frontotemporal dementia (FTD). We aimed to describe behavioral and neuropsychiatric phenotypes in genetic FTD, quantify their temporal association, and investigate their regional association with brain atrophy.

METHODS

We analyzed data of pathogenic variant carriers in the chromosome 9 open reading frame 72 (c9orf72), progranulin (GRN), or microtubule-associated protein tau (MAPT) gene from the Genetic Frontotemporal dementia Initiative cohort study that enrolls both symptomatic pathogenic variant carriers and first-degree relatives of known carriers. Principal component analysis was performed to identify behavioral and neuropsychiatric clusters that were compared with respect to frequency and severity between groups. Associations between neuropsychiatric clusters and MRI-assessed atrophy were determined using voxel-based morphometry. We applied linear mixed effects and generalized linear mixed effects models to assess the longitudinal course of symptoms.

RESULTS

A total of 522 participants were included: 221 c9orf72 (138 presymptomatic), 213 GRN (157 presymptomatic), and 88 MAPT (62 presymptomatic) pathogenic variant carriers. Principal component analysis revealed 5 phenotypic clusters (67.6% of variance), labeled diverse behavioral, affective, psychotic, euphoric/hypersexual, and tactile hallucinations phenotype. In participants presenting behavioral or neuropsychiatric symptoms, affective symptoms were most frequent across groups (83.6%-88.1%), followed by diverse behavioral symptoms (68.4%-77.9%). In c9orf72 and GRN pathogenic variant carriers, psychotic symptoms (32.0% and 19.4%, respectively) were more frequent than euphoric/hypersexual symptoms (28.7% and 14.2%, respectively), which was the other way around in MAPT pathogenic variant carriers (28.6% and 23.8%). Although diverse behavioral symptoms were associated with gray and white matter frontotemporal atrophy, only a small atrophy cluster in the right thalamus was associated with psychotic symptoms. Euphoric/hypersexual symptoms were associated with atrophy in mesial temporal lobes, basal forebrain structures, and the striatum (p < 0.05). Estimated time to symptom onset, genetic group, education, and sex influenced behavioral and neuropsychiatric symptoms (p < 0.05). Particularly, in c9orf72 pathogenic variant carriers, psychotic symptoms may be starting decades before recognition of onset of illness.

DISCUSSION

We identified multiple clusters of behavioral and neuropsychiatric symptoms in participants with genetic FTD that relate to distinct cerebral atrophy patterns. Their severity depends on time, affected gene, sex, and education. These clinical-genetic associations can guide diagnostic evaluations and the design of clinical trials for new disease-modifying and preventive treatments.

Predictors of Care Home Admission and Survival Rate in Patients With Syndromes Associated With Frontotemporal Lobar Degeneration in Europe

BACKGROUND AND OBJECTIVES

Data on care home admission and survival rates of patients with syndromes associated with frontotemporal lobar degeneration (FTLD) are limited. However, their estimation is essential to plan trials and assess the efficacy of intervention. Population-based registers provide unique samples for this estimate. The aim of this study was to assess care home admission rate, survival rate, and their predictors in incident patients with FTLD-associated syndromes from the European FRONTIERS register-based study.

METHODS

We conducted a prospective longitudinal multinational observational registry study, considering incident patients with FTLD-associated syndromes diagnosed between June 1, 2018, and May 31, 2019, and followed for up to 5 years till May 31, 2023. We enrolled patients fulfilling diagnosis of the behavioral variant frontotemporal dementia (bvFTD), primary progressive aphasia (PPA), progressive supranuclear palsy (PSP) or corticobasal syndrome (CBS), and FTD with motor neuron disease (FTD-MND). Kaplan-Meier analysis and Cox multivariable regression models were used to assess care home admission and survival rates. The survival probability score (SPS) was computed based on independent predictors of survivorship.

RESULTS

A total of 266 incident patients with FTLD were included (mean age ± SD = 66.7 ± 9.0; female = 41.4%). The median care home admission rate was 97 months (95% CIs 86-98) from disease onset and 57 months (95% CIs 56-58) from diagnosis. The median survival was 90 months (95% CIs 77-97) from disease onset and 49 months (95% CIs 44-58) from diagnosis. Survival from diagnosis was shorter in FTD-MND (hazard ratio [HR] 4.59, 95% CIs 2.49-8.76, p < 0.001) and PSP/CBS (HR 1.56, 95% CIs 1.01-2.42, p = 0.044) compared with bvFTD; no differences between PPA and bvFTD were found. The SPS proved high accuracy in predicting 1-year survival probability (area under the receiver operating characteristic curve = 0.789, 95% CIs 0.69-0.87), when defined by age, European area of residency, extrapyramidal symptoms, and MND at diagnosis.

DISCUSSION

In FTLD-associated syndromes, survival rates differ according to clinical features and geography. The SPS was able to predict prognosis at individual patient level with an accuracy of ∼80% and may help to improve patient stratification in clinical trials. Future confirmatory studies considering different populations are needed.

Abnormal structural‒functional coupling patterning in progressive supranuclear palsy is associated with diverse gradients and histological features

The anatomy of the brain supports inherent processes, fostering mental abilities and eventually facilitating adaptive behavior. Recent studies have shown that progressive supranuclear palsy (PSP) is accompanied by alterations in functional and structural networks. However, how the structure and function of PSP coordinates change is not clear, and the relationships between structural‒functional coupling (SFC) and the gradient of hierarchical structure and cellular histology remain largely unknown. Here, we use neuroimaging data from two independent cohorts and a public histological dataset to investigate the relationships among the cellular histology, hierarchical structure, and SFC of PSP patients. We find that the SFC of the entire cortex in PSP is severely disrupted, with higher coupling in the visual network (VN). Moreover, coupling differences in PSP follow a macroscopic organizational principle from unimodal to transmodal gradients. Finally, we elucidate greater laminar differentiation in VN regions sensitive to SFC changes in PSP, which is related mainly to the higher cellular density and smaller size of the internal-granular layer. In conclusion, our findings provide an interpretable framework for understanding SFC changes in PSP and provide new insights into the consistency of structural and functional changes in PSP regarding hierarchical structure and cellular histology.

Clinical and molecular predictors of survival among atypical parkinsonian syndromes in a North African tertiary referral center

INTRODUCTION

Atypical Parkinsonian Syndromes(APS) are challenging neurodegenerative disorders due to their heterogeneous phenotypic overlaps.So far,there are no validated biomarkers that can accurately predict disease progression,and survival studies were highly different and contradictory.

AIM

To investigate clinical and molecular survival factors among Tunisian APS patients.

METHODS

A retrospective study included Tunisian APS-patients.Using clinical and molecular parameters,survival was explored by Kaplan-Meier analysis.

RESULTS

We included 409-APS patients divided into 166-DLB,112-PSP,81-MSA and 50-CBS.Survival rate was similar in synucleinopathies, while it differed in tauopathies,being shorter in PSP compared to CBS.Median survival in DLB was different according to gender(p = 0.0048),early parkinsonism and cognitive disorders. Among MSA, prognosis was worse in MSA-C-patients(p = 0.012) and those with stridor(p = 0.0049),oculomotor and neuropsychiatric disorders. For tauopathies, survival was shorter in PSP-RS(p = 0.027),cerebellar phenotype, those with tremor and swallowing problems at onset, early parkinsonism and memory impairment. For CBS,prognosis was worse in patients with tremor,swallowing and cognitive problems.Significant differences were noted in terms of survival across APS non-carriers of APOE-ε4(p < 0.001) as well APS patients carriers of MAPT-H1.PSP patients had lower survival rate according to MAPT haplotype carriage. Moreover, the number of copies had an influence as patients with H1/H2-MAPT profile had better prognosis than those with H1/H1.

CONCLUSION

This study determined survival rates in APS subgroups,which were comparable across synucleinopathies but shorter in PSP and longer in CBS.It also characterized demographic,phenotypic,and genetic profiles identifying more aggressive forms within APS subgroups.These findings address clinical gaps,aiding counseling for patients and families and guiding clinical management.Furthermore,they could facilitate patient stratification in clinical trials where mortality is an outcome measure.

Positive effects of speech and language therapy group interventions in primary progressive aphasia: A systematic review

BACKGROUND

Primary progressive aphasia (PPA) is a neurodegenerative condition characterised by a prominent and progressive deterioration in language abilities, which significantly impacts quality of life and interpersonal relationships. Speech and language therapy plays a crucial role in offering interventions. Group intervention is one mode of delivery that could benefit communication functioning and overall wellbeing of people with PPA (pwPPA) and their care partners. Group interventions are also more efficient than one-to-one intervention and may facilitate peer support.

AIMS

The aim of this review was to systematically evaluate the current evidence for the effectiveness of speech and language therapy groups for pwPPA and their care partners. Specifically, this paper considered three questions: 1.What evidence-based speech and language therapy groups for pwPPA and their care partners have been reported to date? 2.Are group communication interventions effective in improving quality of life and communication function for pwPPA and their care partners? 3.Are group communication interventions that are designed for people with communication difficulties of other aetiologies (such as stroke) effective for pwPPA? In addition, this review aimed to describe the structure and content of groups, including aims, disciplines involved, size and frequency of group meetings, and outcome measures.

METHODS

MEDLINE, CINAHL and PsycINFO were used to retrieve articles of interest. A total of 10 studies published between 2009 and 2022 met the eligibility criteria and therefore were included in this study. Data were extracted from the articles regarding the structure and content of groups.

MAIN CONTRIBUTION

Although evidence is currently limited, results suggest that speech and language therapy group intervention can improve specific linguistic processes, the use of communication strategies and psychosocial well-being. The importance of multidisciplinary input and care partners' involvement in groups was highlighted, along with the benefits of creative non-verbal activities as tools for self-expression. There is also initial evidence that telehealth group provision and one-off group sessions may be feasible and can benefit psychosocial well-being. Lastly, intentional recruitment and explicit education on different aphasia types are described as important when pwPPA participate in groups with mixed diagnoses.

CONCLUSIONS

The literature on speech and language therapy group interventions for PPA shows promise of positive effects on communication function and psychosocial well-being of both pwPPA and their care partners. Speech and language therapists can consider these published interventions when designing and implementing similar groups, but more robust evidence is required to confirm the relative effectiveness of this approach.

WHAT THIS PAPER ADDS

What is already known on this subject Speech pathology led group intervention shows some promise in benefitting communication functioning and overall well-being of pwPPA and their carers, but there has been no systematic evaluation of all the evidence regarding the efficacy of speech and language therapy led groups. Establishing feasibility, acceptability and efficacy of speech and language therapy group interventions for pwPPA and their carers may present a valuable addition for managing this progressive language disability. What this paper adds to existing knowledge Although evidence is currently limited, results from this systematic review suggest that speech and language therapy led group intervention can improve specific linguistic processes, the use of communication strategies and psychosocial well-being for pwPPA and their carers. The importance of multidisciplinary input and carers' involvement in groups was highlighted, along with the benefits of creative non-verbal activities as tools for self-expression. There is also initial evidence that telehealth group provision for carers may be feasible and can benefit psychosocial wellbeing. Lastly, intentional recruitment and explicit education on different aphasia types are described as important when pwPPA participate in groups with mixed diagnoses. What are the potential or actual clinical implications of this work? A synthesis of the evidence base for speech and language therapy led PPA groups, as well as a description of the group components and formats, will be valuable for clinical service planning, and will guide future examination of group options for pwPPA and their carers. Speech and language therapists can also consider the research findings from this systematic review when designing and implementing similar groups in their local context.

Cerebral Glucose Metabolism Is a Valuable Predictor of Survival in Patients with Lewy Body Diseases

OBJECTIVE

Patients with Lewy body diseases have an increased risk of dementia, which is a significant predictor for survival. Posterior cortical hypometabolism on [18F]fluorodeoxyglucose positron emission tomography (PET) precedes the development of dementia by years. We therefore examined the prognostic value of cerebral glucose metabolism for survival.

METHODS

We enrolled patients diagnosed with Parkinson's disease (PD), Parkinson's disease with dementia, or dementia with Lewy bodies who underwent [18F]fluorodeoxyglucose PET. Regional cerebral metabolism of each patient was analyzed by determining the expression of the PD-related cognitive pattern (Z-score) and by visual PET rating. We analyzed the predictive value of PET for overall survival using Cox regression analyses (age- and sex-corrected) and calculated prognostic indices for the best model.

RESULTS

Glucose metabolism was a significant predictor of survival in 259 included patients (n = 118 events; hazard ratio: 1.4 [1.2-1.6] per Z-score; hazard ratio: 1.8 [1.5-2.2] per visual PET rating score; both p < 0.0001). Risk stratification with visual PET rating scores yielded a median survival of 4.8, 6.8, and 12.9 years for patients with severe, moderate, and mild posterior cortical hypometabolism (median survival not reached for normal cortical metabolism). Stratification into 5 groups based on the prognostic index revealed 10-year survival rates of 94.1%, 78.3%, 34.7%, 0.0%, and 0.0%.

INTERPRETATION

Regional cerebral glucose metabolism is a significant predictor of survival in Lewy body diseases and may allow an earlier survival prediction than the clinical milestone "dementia." Thus, [18F]fluorodeoxyglucose PET may improve the basis for therapy decisions, especially for invasive therapeutic procedures like deep brain stimulation in Parkinson's disease. ANN NEUROL 2024;96:539-550.

Behavioral Treatment for Speech and Language in Primary Progressive Aphasia and Primary Progressive Apraxia of Speech: A Systematic Review

Primary progressive aphasia (PPA) and primary progressive apraxia of speech (PPAOS) are neurodegenerative syndromes characterized by progressive decline in language or speech. There is a growing number of studies investigating speech-language interventions for PPA/PPAOS. An updated systematic evaluation of the treatment evidence is warranted to inform best clinical practice and guide future treatment research. We systematically reviewed the evidence for behavioral treatment for speech and language in this population. Reviewed articles were published in peer-reviewed journals through 31 May 2021. We evaluated level of evidence, reporting quality, and risk of bias using a modified version of the American Speech-Language Hearing Association (ASHA) Levels of Evidence, an appraisal point system, additional reporting quality and internal/external validity items, and, as appropriate, the Single Case Experimental Design Scale or the Physiotherapy Evidence Database - PsycBITE Rating Scale for Randomized and Non-Randomized Controlled Trials. Results were synthesized using quantitative summaries and narrative review. A total of 103 studies reported treatment outcomes for 626 individuals with PPA; no studies used the diagnostic label PPAOS. Most studies evaluated interventions for word retrieval. The highest-quality evidence was provided by 45 experimental and quasi-experimental studies (16 controlled group studies, 29 single-subject designs). All (k = 45/45) reported improvement on a primary outcome measure; most reported generalization (k = 34/43), maintenance (k = 34/39), or social validity (k = 17/19) of treatment for at least one participant. The available evidence supports speech-language intervention for persons with PPA; however, treatment for PPAOS awaits systematic investigation. Implications and limitations of the evidence and the review are discussed.

CSF Proteomics in Patients With Progressive Supranuclear Palsy

BACKGROUND AND OBJECTIVES

Identification of fluid biomarkers for progressive supranuclear palsy (PSP) is critical to enhance therapeutic development. We implemented unbiased DNA aptamer (SOMAmer) proteomics to identify novel CSF PSP biomarkers.

METHODS

This is a cross-sectional study in original (18 clinically diagnosed PSP-Richardson syndrome [PSP-RS], 28 cognitively healthy controls]), validation (23 PSP-RS, 26 healthy controls), and neuropathology-confirmed (21 PSP, 52 non-PSP frontotemporal lobar degeneration) cohorts. Participants were recruited through the University of California, San Francisco, and the 4-Repeat Neuroimaging Initiative. The original and neuropathology cohorts were analyzed with the SomaScan platform version 3.0 (5026-plex) and the validation cohort with version 4.1 (7595-plex). Clinical severity was measured with the PSP Rating Scale (PSPRS). CSF proteomic data were analyzed to identify differentially expressed targets, implicated biological pathways using enrichment and weighted consensus gene coexpression analyses, diagnostic value of top targets with receiver-operating characteristic curves, and associations with disease severity with linear regressions.

RESULTS

A total of 136 participants were included (median age 70.6 ± 8 years, 68 [50%] women). One hundred fifty-five of 5,026 (3.1%), 959 of 7,595 (12.6%), and 321 of 5,026 (6.3%) SOMAmers were differentially expressed in PSP compared with controls in original, validation, and neuropathology-confirmed cohorts, with most of the SOMAmers showing reduced signal (83.1%, 95.1%, and 73.2%, respectively). Three coexpression modules were associated with PSP across cohorts: (1) synaptic function/JAK-STAT (β = -0.044, corrected p = 0.002), (2) vesicle cytoskeletal trafficking (β = 0.039, p = 0.007), and (3) cytokine-cytokine receptor interaction (β = -0.032, p = 0.035) pathways. Axon guidance was the top dysregulated pathway in PSP in original (strength = 1.71, p < 0.001), validation (strength = 0.84, p < 0.001), and neuropathology-confirmed (strength = 0.78, p < 0.001) cohorts. A panel of axon guidance pathway proteins discriminated between PSP and controls in original (area under the curve [AUC] = 0.924), validation (AUC = 0.815), and neuropathology-confirmed (AUC = 0.932) cohorts. Two inflammatory proteins, galectin-10 and cytotoxic T lymphocyte-associated protein-4, correlated with PSPRS scores across cohorts.

DISCUSSION

Axon guidance pathway proteins and several other molecular pathways are downregulated in PSP, compared with controls. Proteins in these pathways may be useful targets for biomarker or therapeutic development.

Dysfluency in primary progressive aphasia: Temporal speech parameters

Analysing spontaneous speech in individuals experiencing fluency difficulties holds potential for diagnosing speech and language disorders, including Primary Progressive Aphasia (PPA). Dysfluency in the spontaneous speech of patients with PPA has mostly been described in terms of abnormal pausing behaviour, but the temporal features related to speech have drawn little attention. This study compares speech-related fluency parameters in the three main variants of PPA and in typical speech. Forty-three adults participated in this research, thirteen with the logopenic variant of PPA (lvPPA), ten with the non-fluent variant (nfvPPA), nine with the semantic variant (svPPA), and eleven who were healthy age-matched adults. Participants' fluency was assessed through a picture description task from which 42 parameters were computed including syllable duration, speaking pace, the duration of speech chunks (i.e. interpausal units, IPU), and the number of linguistic units per IPU and per second. The results showed that each PPA variant exhibited abnormal speech characteristics reflecting various underlying factors, from motor speech deficits to higher-level issues. Out of the 42 parameters considered, 37 proved useful for characterising dysfluency in the three main PPA variants and 35 in distinguishing among them. Therefore, taking into account not only pausing behaviour but also temporal speech parameters can provide a fuller understanding of dysfluency in PPA. However, no single parameter by itself sufficed to distinguish one PPA group from the other two, further evidence that dysfluency is not dichotomous but rather multidimensional, and that complementary multiparametric analyses are needed.

Pharmacotherapies for the Treatment of Progressive Supranuclear Palsy: A Narrative Review

Progressive supranuclear palsy (PSP) is a neurodegenerative disorder resulting from the deposition of misfolded and neurotoxic forms of tau protein in specific areas of the midbrain, basal ganglia, and cortex. It is one of the most representative forms of tauopathy. PSP presents in several different phenotypic variations and is often accompanied by the development of concurrent neurodegenerative disorders. PSP is universally fatal, and effective disease-modifying therapies for PSP have not yet been identified. Several tau-targeting treatment modalities, including vaccines, monoclonal antibodies, and microtubule-stabilizing agents, have been investigated and have had no efficacy. The need to treat PSP and other tauopathies is critical, and many clinical trials investigating tau-targeted treatments are underway. In this review, the PubMed database was queried to collect information about preclinical and clinical research on PSP treatment. Additionally, the US National Library of Medicine's ClinicalTrials.gov website was queried to identify past and ongoing clinical trials relevant to PSP treatment. This narrative review summarizes our findings regarding these reports, which include potential disease-modifying drug trials, modifiable risk factor management, and symptom treatments.

Clinical criteria for a limbic-predominant amnestic neurodegenerative syndrome

Predominant limbic degeneration has been associated with various underlying aetiologies and an older age, predominant impairment of episodic memory and slow clinical progression. However, the neurological syndrome associated with predominant limbic degeneration is not defined. This endeavour is critical to distinguish such a syndrome from those originating from neocortical degeneration, which may differ in underlying aetiology, disease course and therapeutic needs. We propose a set of clinical criteria for a limbic-predominant amnestic neurodegenerative syndrome that is highly associated with limbic-predominant age-related TDP-43 encephalopathy but also other pathologic entities. The criteria incorporate core, standard and advanced features, including older age at evaluation, mild clinical syndrome, disproportionate hippocampal atrophy, impaired semantic memory, limbic hypometabolism, absence of neocortical degeneration and low likelihood of neocortical tau, with degrees of certainty (highest, high, moderate and low). We operationalized this set of criteria using clinical, imaging and biomarker data to validate its associations with clinical and pathologic outcomes. We screened autopsied patients from Mayo Clinic and Alzheimer's Disease Neuroimaging Initiative cohorts and applied the criteria to those with an antemortem predominant amnestic syndrome (Mayo, n = 165; Alzheimer's Disease Neuroimaging Initiative, n = 53) and who had Alzheimer's disease neuropathological change, limbic-predominant age-related TDP-43 encephalopathy or both pathologies at autopsy. These neuropathology-defined groups accounted for 35, 37 and 4% of cases in the Mayo cohort, respectively, and 30, 22 and 9% of cases in the Alzheimer's Disease Neuroimaging Initiative cohort, respectively. The criteria effectively categorized these cases, with Alzheimer's disease having the lowest likelihoods, limbic-predominant age-related TDP-43 encephalopathy patients having the highest likelihoods and patients with both pathologies having intermediate likelihoods. A logistic regression using the criteria features as predictors of TDP-43 achieved a balanced accuracy of 74.6% in the Mayo cohort, and out-of-sample predictions in an external cohort achieved a balanced accuracy of 73.3%. Patients with high likelihoods had a milder and slower clinical course and more severe temporo-limbic degeneration compared to those with low likelihoods. Stratifying patients with both Alzheimer's disease neuropathological change and limbic-predominant age-related TDP-43 encephalopathy from the Mayo cohort according to their likelihoods revealed that those with higher likelihoods had more temporo-limbic degeneration and a slower rate of decline and those with lower likelihoods had more lateral temporo-parietal degeneration and a faster rate of decline. The implementation of criteria for a limbic-predominant amnestic neurodegenerative syndrome has implications to disambiguate the different aetiologies of progressive amnestic presentations in older age and guide diagnosis, prognosis, treatment and clinical trials.

Cope PPA-Adaptation of the Biographic-Narrative Approach for Persons with Primary Progressive Aphasia: Protocol for Clinical Trial Design

Persons with primary progressive aphasia (PPA) often experience limitations in their quality of life (QoL). Some studies have shown positive effects of speech and language therapy on QoL in persons with PPA. However, there is still a lack of evidence for disorder-specific approaches for this important therapeutic goal. The biographic-narrative approach (narraktiv) has been shown to significantly improve QoL in persons with post-stroke aphasia. In the planned study, the biographic-narrative approach will be adapted for persons with PPA (Cope PPA), and its efficacy will be investigated. First, a focus group interview with five persons with PPA will be conducted to identify the wishes and needs of participants. Based on the results, the narraktiv manual according to Corsten et al. (2015) will be revised. Second, an efficacy study will be conducted according to the new Cope PPA manual with 24 persons with PPA in a waiting group control design. The primary outcome, QoL, will be assessed using questionnaires (Stroke and Aphasia Quality of Life Scale-39) and semistructured interviews. Depressive symptoms, life satisfaction and cognitive/communicative functioning will also be assessed. If Cope PPA proves efficacy, this study may help to improve the treatment of persons with PPA.

Age-specific prevalence of the different clinical presentations of AD and FTD in young-onset dementia

BACKGROUND

Studies have shown that the prevalence of all-variants Alzheimer's disease (AD) and frontotemporal dementia (FTD) both increase with age, even before the age of 65. However, it is not known whether their different clinical presentations all increase in prevalence with age in the same way.

METHODS

We studied the prevalence of the different clinical presentations of young-onset AD and FTD by 5-year age groups in a population-based study identifying all dementia patients with a diagnosis of AD and FTD and symptoms onset before age 65 in the Modena province, Italy. By using regression models of cumulative occurrences, we also estimated age-specific prevalence and compared the growth curves of the clinical presentations.

RESULTS

The prevalence of all-variants AD increased with age, from 18/1,000,000 in the 40-44 age group to 1411/1,000,000 in the 60-64 age group. The prevalence of all-variants FTD also increased with age, from 18/1,000,000 to 866/1,000,000. An estimation of age-specific prevalence functions of each clinical presentation showed that atypical non-amnestic AD and aphasic FTD grew the most in early ages, followed by the behavioural variant of FTD (bvFTD). Then, around the age of 60, amnestic AD took over and its age-specific prevalence continued to increase disproportionally compared to all the other clinical variants of AD and FTD, which, instead, started to decrease in prevalence.

CONCLUSIONS

Amnestic AD is the clinical presentation that increases the most with advancing age, followed by bvFTD, suggesting that there is a differential vulnerability to the effect of ageing within the same neurodegenerative disease.

'Communication is difficult': Speech, language and communication needs of people with young onset or rarer forms of non-language led dementia

BACKGROUND

People with behavioural variant frontotemporal dementia, Lewy body dementia, posterior cortical atrophy and young onset Alzheimer's disease may experience language and communication difficulties. However, the role of speech and language interventions for people with these non-language led dementias has received little attention.

AIMS

This study aimed to explore the experiences and perspectives of people living with these conditions, and their families, regarding their language and communication difficulties and how speech and language therapy could address these needs.

METHODS

This study employed a qualitative design to explore the experiences of people living with or caring for somebody with behavioural variant frontotemporal dementia, Lewy body dementia, posterior cortical atrophy or young onset Alzheimer's disease, and to understand their opinions about speech and language therapy. Participants were recruited from a support service connected to a dementia clinic to attend one of five focus group meetings. Videorecorded focus groups and interviews were transcribed, and reflexive thematic analysis was used to analyse data from people affected by each type of dementia.

RESULTS

A total of 25 participants were recruited to the study, with representation across the different forms of non-language led dementias. The four main themes identified were: (1) communication difficulties as a key difficulty, (2) loss and loneliness, (3) speech and language therapy, and (4) the role of the caregiver. Sixteen subthemes were also identified which highlighted individual issues across disease types.

DISCUSSION

Although all the forms of dementia studied here are not considered to be language-led, people with these conditions and/or their care partners identified speech, language and communication as common challenges. These communication difficulties were reported to have a negative impact on their social participation and mental health and participants felt speech and language interventions could help. There is a need for research exploring speech and language interventions developed for and with people with non-language led dementias and their care partners, to ensure they meet the needs of the people they are designed for.

WHAT THIS PAPER ADDS

What is already known on the subject People with primary progressive aphasia present with speech, language and communication difficulties, and several speech and language interventions have been developed to meet the needs of this population. However, people with non-language led dementias may also experience speech, language and communication difficulties, and little is known about interventions that may address these difficulties. What this paper adds to existing knowledge People living with or caring for somebody with behavioural variant frontotemporal dementia, Lewy body dementia, posterior cortical atrophy and young onset Alzheimer's disease report experiencing speech, language and communication difficulties that impact on the person with dementia's social participation and mood. Participants in this study also shared their opinions about how speech and language interventions could help, from the earliest stages of the disease. What are the potential or actual clinical implications of this work? Speech and language therapists need to address the individual speech, language and communication needs of people with dementias, even those that are not thought to be language-led. Current speech and language therapy service provision does not meet the needs of people with non-language led dementias and further research is required to develop interventions and services to meet these needs.

Comprehensive assessment of TDP-43 neuropathology data in the National Alzheimer's Coordinating Center database

TDP-43 proteinopathy is a salient neuropathologic feature in a subset of frontotemporal lobar degeneration (FTLD-TDP), in amyotrophic lateral sclerosis (ALS-TDP), and in limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC), and is associated with hippocampal sclerosis of aging (HS-A). We examined TDP-43-related pathology data in the National Alzheimer's Coordinating Center (NACC) in two parts: (I) availability of assessments, and (II) associations with clinical diagnoses and other neuropathologies in those with all TDP-43 measures available. Part I: Of 4326 participants with neuropathology data collected using forms that included TDP-43 assessments, data availability was highest for HS-A (97%) and ALS (94%), followed by FTLD-TDP (83%). Regional TDP-43 pathologic assessment was available for 77% of participants, with hippocampus the most common region. Availability for the TDP-43-related measures increased over time, and was higher in centers with high proportions of participants with clinical FTLD. Part II: In 2142 participants with all TDP-43-related assessments available, 27% of participants had LATE-NC, whereas ALS-TDP or FTLD-TDP (ALS/FTLD-TDP) was present in 9% of participants, and 2% of participants had TDP-43 related to other pathologies ("Other TDP-43"). HS-A was present in 14% of participants, of whom 55% had LATE-NC, 20% ASL/FTLD-TDP, 3% Other TDP-43, and 23% no TDP-43. LATE-NC, ALS/FTLD-TDP, and Other TDP-43, were each associated with higher odds of dementia, HS-A, and hippocampal atrophy, compared to those without TDP-43 pathology. LATE-NC was associated with higher odds for Alzheimer's disease (AD) clinical diagnosis, AD neuropathologic change (ADNC), Lewy bodies, arteriolosclerosis, and cortical atrophy. ALS/FTLD-TDP was associated with higher odds of clinical diagnoses of primary progressive aphasia and behavioral-variant frontotemporal dementia, and cortical/frontotemporal lobar atrophy. When using NACC data for TDP-43-related analyses, researchers should carefully consider the incomplete availability of the different regional TDP-43 assessments, the high frequency of participants with ALS/FTLD-TDP, and the presence of other forms of TDP-43 pathology.

A neuroanatomical and cognitive model of impaired social behaviour in frontotemporal dementia

Impaired social cognition is a core deficit in frontotemporal dementia (FTD). It is most commonly associated with the behavioural-variant of FTD, with atrophy of the orbitofrontal and ventromedial prefrontal cortex. Social cognitive changes are also common in semantic dementia, with atrophy centred on the anterior temporal lobes. The impairment of social behaviour in FTD has typically been attributed to damage to the orbitofrontal cortex and/or temporal poles and/or the uncinate fasciculus that connects them. However, the relative contributions of each region are unresolved. In this review, we present a unified neurocognitive model of controlled social behaviour that not only explains the observed impairment of social behaviours in FTD, but also assimilates both consistent and potentially contradictory findings from other patient groups, comparative neurology and normative cognitive neuroscience. We propose that impaired social behaviour results from damage to two cognitively- and anatomically-distinct components. The first component is social-semantic knowledge, a part of the general semantic-conceptual system supported by the anterior temporal lobes bilaterally. The second component is social control, supported by the orbitofrontal cortex, medial frontal cortex and ventrolateral frontal cortex, which interacts with social-semantic knowledge to guide and shape social behaviour.

Long-term, home-based transcranial direct current stimulation coupled with computerized cognitive training in frontotemporal dementia: A case report

We present the case of a 62-year-old woman with probable behavioral variant of frontotemporal dementia (bvFTD) with cognitive/language deficits who demonstrated improved performance on cognitive/language testing and in functional tasks following long-term, home-based transcranial direct current stimulation (tDCS) coupled with computerized cognitive training (CCT). The patient underwent home-based tDCS (anode on the left prefrontal cortex and cathode on the right homologue) for 46 sessions over 10 weeks along with CCT. On post-treatment testing, the patient improved by 3 points on the Mini-Mental State Exam (MMSE) (23 to 26). She also showed improvement on several cognitive/language tasks, such as immediate recall of single words and word pairs, total accurate words in sentence repetition, delayed recall, semantic processing, and sentence level comprehension. There was no decline in several other cognitive and language tasks. Family members reported subjective improvements in expressiveness, communication, and interaction with others as well as increased attention to grooming and style which contrasted with her pre-treatment condition. This report suggests that home-based tDCS combined with CCT for an extended period may slow decline, and improve cognitive/language performance and everyday function in FTD.

Error profiles of facial emotion recognition in frontotemporal dementia and Alzheimer's disease

OBJECTIVES

To identify the patterns of errors in facial emotion recognition in frontotemporal dementia (FTD) subtypes compared with Alzheimer's disease (AD) and healthy controls.

DESIGN

Retrospective analysis.

SETTING

Participants were recruited from FRONTIER, the frontotemporal dementia research group at the University of Sydney, Australia.

PARTICIPANTS

A total of 356 participants (behavioral-variant FTD (bvFTD): 62, semantic dementia (SD)-left: 29, SD-right: 14, progressive non-fluent aphasia (PNFA): 21, AD: 76, controls: 90) were included.

MEASUREMENTS

Facial emotion recognition was assessed using the Facial Affect Selection Task, a word-face matching task measuring recognition of the six basic emotions (anger, disgust, fear, happiness, sadness, and surprise), as well as neutral emotion, portrayed by black and white faces.

RESULTS

Overall, all clinical groups performed significantly worse than controls with the exception of the PNFA subgroup (p = .051). The SD-right group scored worse than all other clinical groups (all p values < .027) and the bvFTD subgroup performed worse than the PNFA group (p < .001). The most frequent errors were in response to the facial emotions disgust (26.1%) and fear (22.9%). The primary error response to each target emotion was identified; patterns of errors were similar across all clinical groups.

CONCLUSIONS

Facial emotion recognition is impaired in FTD and AD compared to healthy controls. Within FTD, bvFTD and SD-right are particularly impaired. Dementia groups cannot be distinguished based on error responses alone. Implications for future clinical diagnosis and research are discussed.

Non-pharmacological interventions for improving language and communication in people with primary progressive aphasia

BACKGROUND

Primary progressive aphasia (PPA) accounts for approximately 43% of frontotemporal dementias and is mainly characterised by a progressive impairment of speech and communication abilities. Three clinical variants have been identified: (a) non-fluent/agrammatic, (b) semantic, and (c) logopenic/phonological PPA variants. There is currently no curative treatment for PPA, and the disease progresses inexorably over time, with devastating effects on speech and communication ability, functional status, and quality of life. Several non-pharmacological interventions that may improve symptoms (e.g. different forms of language training and non-invasive brain stimulation) have been investigated in people with PPA.

OBJECTIVES

To assess the effects of non-pharmacological interventions for people with PPA on word retrieval (our primary outcome), global language functions, cognition, quality of life, and adverse events.

SEARCH METHODS

We searched the Cochrane Dementia and Cognitive Improvement Group's trial register, MEDLINE (Ovid SP), Embase (Ovid SP), four other databases and two other trial registers. The latest searches were run on 26 January 2024.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) evaluating the effects of non-pharmacological interventions in people with PPA.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

There were insufficient data available to conduct the network meta-analyses that we had originally planned (due to trial data being insufficiently reported or not reported at all, as well as the heterogeneous content of the included interventions). Therefore, we provide a descriptive summary of the included studies and results. We included 10 studies, with a total of 132 participants, evaluating non-pharmacological interventions. These were: transcranial direct current stimulation (tDCS) or repetitive transcranial magnetic stimulation (rTMS) as stand-alone treatments (used by two and one studies, respectively); tDCS combined with semantic and phonological word-retrieval training (five studies); tDCS combined with semantic word-retrieval training (one study); and tDCS combined with phonological word-retrieval training (one study). Results for our primary outcome of word retrieval were mixed. For the two studies that investigated the effects of tDCS as stand-alone treatment compared to placebo ("sham") tDCS, we rated the results as having very low-certainty evidence. One study found a significant beneficial effect on word retrieval after active tDCS; one study did not report any significant effects in favour of the active tDCS group. Five studies investigated tDCS administered to the dorsolateral prefrontal cortex, inferior frontal cortex, left frontotemporal region, or the temporoparietal cortex, combined with semantic and phonological word-retrieval training. The most consistent finding was enhancement of word-retrieval ability for trained items immediately after the intervention, when behavioural training was combined with active tDCS compared to behavioural training plus sham tDCS. We found mixed effects for untrained items and maintenance of treatment effects during follow-up assessments. We rated the certainty of the evidence as very low in all studies. One study investigated tDCS combined with semantic word-retrieval training. Training was provided across 15 sessions with a frequency of three to five sessions per week, depending on the personal preferences of the participants. tDCS targeted the left frontotemporal region. The study included three participants: two received 1 mA stimulation and one received 2 mA stimulation. The study showed mixed results. We rated it as very low-certainty evidence. One study investigated tDCS combined with phonological word-retrieval training. Training was again provided across 15 sessions over a period of three weeks. tDCS targeted the left inferior frontal gyrus. This study showed a significantly more pronounced improvement for trained and untrained words in favour of the group that had received active tDCS, but we rated the certainty of the evidence as very low. One study compared active rTMS applied to an individually determined target site to active rTMS applied to a control site (vertex) for effects on participants' word retrieval. This study demonstrated better word retrieval for active rTMS administered to individually determined target brain regions than in the control intervention, but we rated the results as having a very low certainty of evidence. Four studies assessed overall language ability, three studies assessed cognition, five studies assessed potential adverse effects of brain stimulation, and one study investigated quality of life.

AUTHORS' CONCLUSIONS

There is currently no high-certainty evidence to inform clinical decision-making regarding non-pharmacological treatment selection for people with PPA. Preliminary evidence suggests that the combination of active tDCS with specific language therapy may improve impaired word retrieval for specifically trained items beyond the effects of behavioural treatment alone. However, more research is needed, including high-quality RCTs with detailed descriptions of participants and methods, and consideration of outcomes such as quality of life, depressive symptoms, and overall cognitive functioning. Moreover, studies assessing optimal treatments (i.e. behavioural interventions, brain stimulation interventions, and their combinations) for individual patients and PPA subtypes are needed. We were not able to conduct the planned (network) meta-analyses due to missing data that could not be obtained from most of the authors, a general lack of RCTs in the field, and heterogeneous interventions in eligible trials. Journals should implement a mandatory data-sharing requirement to assure transparency and accessibility of data from clinical trials.

Limbic-predominant age-related TDP-43 encephalopathy (LATE-NC): Co-pathologies and genetic risk factors provide clues about pathogenesis

Limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC) is detectable at autopsy in more than one-third of people beyond age 85 years and is robustly associated with dementia independent of other pathologies. Although LATE-NC has a large impact on public health, there remain uncertainties about the underlying biologic mechanisms. Here, we review the literature from human studies that may shed light on pathogenetic mechanisms. It is increasingly clear that certain combinations of pathologic changes tend to coexist in aging brains. Although "pure" LATE-NC is not rare, LATE-NC often coexists in the same brains with Alzheimer disease neuropathologic change, brain arteriolosclerosis, hippocampal sclerosis of aging, and/or age-related tau astrogliopathy (ARTAG). The patterns of pathologic comorbidities provide circumstantial evidence of mechanistic interactions ("synergies") between the pathologies, and also suggest common upstream influences. As to primary mediators of vulnerability to neuropathologic changes, genetics may play key roles. Genes associated with LATE-NC include TMEM106B, GRN, APOE, SORL1, ABCC9, and others. Although the anatomic distribution of TDP-43 pathology defines the condition, important cofactors for LATE-NC may include Tau pathology, endolysosomal pathways, and blood-brain barrier dysfunction. A review of the human phenomenology offers insights into disease-driving mechanisms, and may provide clues for diagnostic and therapeutic targets.

Beauty and Paintings: Aesthetic Experience in Patients with Behavioral Variant Frontotemporal Dementia When Viewing Abstract and Concrete Paintings

We assessed the aesthetic experience of patients with behavioral variant frontotemporal dementia (bvFTD) to understand their ability to experience feelings of the sublime and to be moved when viewing paintings. We exposed patients with bvFTD and control participants to concrete and abstract paintings and asked them how moved they were by these paintings and whether the latter were beautiful or ugly. Patients with bvFTD declared being less moved than control participants by both abstract and concrete paintings. No significant differences were observed between abstract and concrete paintings in both patients with bvFTD and control participants. Patients with bvFTD provided fewer "beautiful" and more "ugly" responses than controls for both abstract and concrete paintings. No significant differences in terms of "beautiful" and "ugly" responses were observed between abstract and concrete paintings in both patients with bvFTD and control participants. These findings suggest disturbances in the basic affective experience of patients with bvFTD when they are exposed to paintings, as well as a bias in their ability to judge the aesthetic quality of paintings.

Introduction to Large Language Models (LLMs) for dementia care and research

Introduction

Dementia is a progressive neurodegenerative disorder that affects cognitive abilities including memory, reasoning, and communication skills, leading to gradual decline in daily activities and social engagement. In light of the recent advent of Large Language Models (LLMs) such as ChatGPT, this paper aims to thoroughly analyse their potential applications and usefulness in dementia care and research.

Method

To this end, we offer an introduction into LLMs, outlining the key features, capabilities, limitations, potential risks, and practical considerations for deployment as easy-to-use software (e.g., smartphone apps). We then explore various domains related to dementia, identifying opportunities for LLMs to enhance understanding, diagnostics, and treatment, with a broader emphasis on improving patient care. For each domain, the specific contributions of LLMs are examined, such as their ability to engage users in meaningful conversations, deliver personalized support, and offer cognitive enrichment. Potential benefits encompass improved social interaction, enhanced cognitive functioning, increased emotional well-being, and reduced caregiver burden. The deployment of LLMs in caregiving frameworks also raises a number of concerns and considerations. These include privacy and safety concerns, the need for empirical validation, user-centered design, adaptation to the user's unique needs, and the integration of multimodal inputs to create more immersive and personalized experiences. Additionally, ethical guidelines and privacy protocols must be established to ensure responsible and ethical deployment of LLMs.

Results

We report the results on a questionnaire filled in by people with dementia (PwD) and their supporters wherein we surveyed the usefulness of different application scenarios of LLMs as well as the features that LLM-powered apps should have. Both PwD and supporters were largely positive regarding the prospect of LLMs in care, although concerns were raised regarding bias, data privacy and transparency.

Discussion

Overall, this review corroborates the promising utilization of LLMs to positively impact dementia care by boosting cognitive abilities, enriching social interaction, and supporting caregivers. The findings underscore the importance of further research and development in this field to fully harness the benefits of LLMs and maximize their potential for improving the lives of individuals living with dementia.