Citations

Objective Age of symptom onset is highly variable in familial frontotemporal lobar degeneration (f‐FTLD). Accurate prediction of onset would inform clinical management and trial enrollment. Prior studies indicate that individualized maps of brain atrophy can predict conversion to dementia in f‐FTLD. We used a Bayesian linear mixed‐effect (BLME) prediction method for identifying accelerated brain volume loss to predict conversion to dementia. Methods Participants included 234 asymptomatic or prodromal carriers of C9orf72 , GRN , or MAPT mutations (including 21 dementia converters) with ≥3 longitudinal magnetic resonance imaging (MRI) T1‐weighted scans. The BLME models established individual voxel‐wise gray matter trajectories using the first 2 scans. Person‐specific clusters of accelerated volume loss were estimated in subsequent scans and tested as predictors of dementia conversion compared with other approaches in time‐varying Cox proportional hazard models covarying for age. Receiver‐operating characteristic (ROC) curves estimated utility of cluster volume in discriminating which participants converted to dementia within 24 months. Results The BLME cluster volume predicted conversion to dementia in f‐FTLD mutation carriers overall and separately in C9orf72 , GRN , and MAPT , with comparable hazard ratios observed for atrophy W‐maps and regional volumes. Within a 24‐month timeframe, BLME cluster volume discriminated dementia converters from non‐converters with larger areas under the curve (AUCs) than other approaches. Interpretation Bayesian‐modeled individualized atrophy scores predict dementia progression among asymptomatic f‐FTLD mutation carriers and may have increased utility compared with other structural imaging methods when studying individuals over shorter timeframes that align with clinical trial design. ANN NEUROL 20269999:n/a–n/a

Abstract Background Frontotemporal dementia (FTD) with right anterior temporal lobe (RATL) predominant atrophy is an emerging area of interest. Recent findings by the International Working Group (IWG) have identified this subtype as having a distinct clinical profile within the FTD spectrum (Ulugut et al., 2024, A&D). However, its genetic and pathological underpinnings remain unexplored in large, multicultural cohorts. Methods Retrospective analyses encompassing clinical, genetic, pathological, and neuroimaging data from 23 IWG sites across 13 countries in Asia, Middle East, Europe, North and South America were conducted. The study included 444 patients with FTD exhibiting predominant RATL atrophy. Results Genetic screening was performed on 51% ( n = 225) of the cohort for at least the major frontotemporal lobar degeneration (FTLD) mutations including microtubule‐associated protein tau ( MAPT ), progranulin ( GRN ), and chromosome 9 open reading frame 72 ( C9orf72 ), or dementia panels encompassing extended sets of genes. Of these, 81% were sporadic, showing negative results for the screened genes and a modified Goldman Score of ≥ 3, indicating a negative family history for dementia. The MAPT mutation was the most common genetic variant, identified in 7% of the screened cases (Figure 1). Pathological confirmation was available for 63 patients. Among the sporadic cases, transactive response DNA‐binding protein 43 type C (TDP‐C) pathology was most prevalent (60%, n = 32), while tau‐MAPT pathology was most common in the genetic cases (38%, n = 16). Fifteen cases did not fit neatly into genetic or sporadic categories, displaying heterogeneous pathologies (Figure 2). At the initial visit, compared to genetic cases, patients with TDP‐C pathology were older, and more frequently exhibited semantic deficits, with less frequent attention difficulties and executive dysfunction. No differences were observed in sex distribution, symptom duration or disease severity between genetic and sporadic TDP‐C cases. However, left handedness was more common in TDP‐C cases (14%) compared to genetic cases (5%). Conclusion While FTD with RATL atrophy primarily appears sporadic, a significant proportion of cases exhibit genetic variants. These sporadic and genetic subtypes display distinct neuropathological features and clinical manifestations. Given the implications for therapeutic strategies, precise clinical and molecular subtyping is critical for enhancing patient management and ensuring appropriate enrollment in clinical trials.

Abstract Background Agitation is a clinically significant symptom contributing to behavioral and psychological symptoms of dementia (BPSD) but is poorly understood across the different syndromes related to Frontotemporal Lobar Degeneration (FTLD). This study investigates sex differences in agitation across FTLD‐related syndromes and its relationship to various neuropsychiatric symptoms (NPS). Method We analyzed data from 1,654 participants (916 males, 738 females; average ages 65.8 and 65.9, respectively) from the National Alzheimer's Coordinating Center (NACC) and ARTFL‐LEFFTDS Longitudinal Frontotemporal Lobar Degeneration (ALLFTD) study with a FTLD‐related syndrome: behavioral variant FTD (bvFTD), Primary Progressive Aphasia (non‐fluent variant (nfvPPA), semantic variant (svPPA)), Corticobasal syndrome (CBS) and Progressive Supranuclear Palsy (PSP). Participants’ symptoms were assessed using the Neuropsychiatric Inventory (NPI). Prevalence ratios and odds ratios were computed to assess the likelihood of NPS comorbidities when agitation was present in males and females. Principal Component Analysis (PCA) was performed to identify NPS associated with agitation and how they varied by sex. Result Males were more likely to experience anxiety (bvFTD: p <0.001, CBS: p <0.01, PSP: p <0.0001), apathy (nfvPPA: p <0.01, PSP: p <0.01), depression (bvFTD: p <0.0001, PSP<0.01), disinhibition (nfvPPA: p <0.0001), PSP: p <0.001), and motor symptoms (bvFTD: p <0.01, CBS: p <0.01) when agitation was present. In contrast, females had a higher likelihood of experiencing disinhibition in svPPA ( p <0.001). These findings suggest that agitation is associated with a wider range of NPS in males than in females. Agitation and NPS are especially prominent in males with PSP. Conclusion This study reveals significant sex differences in NPS in FTLD‐related syndromes when agitation is present. Males and especially PSP, are more likely to experience a broader range of NPS in association with agitation. These findings underscore the need for further investigation into the underlying mechanisms driving these sex differences, particularly focusing on the neurobiological impact of agitation, the recognition of symptoms in the presence of greater behavioral disturbances, and potential variations from informant reports. Understanding these factors will provide valuable insights into the role of agitation in the presentation of NPS across FTLD‐related syndromes. Ultimately, addressing these gaps will enhance our ability to effectively treat and manage agitation in both male and female patients with FTLD‐related syndromes.

Abstract Background Staging disease severity in dementia research requires input from an informant. The Clinical Dementia Rating Sum of Boxes (CDR) is the most used instrument for staging in Alzheimer's Disease (AD); but has been expanded to stage patients with frontotemporal lobar degeneration (FTLD) with the CDR PLUS NACC‐FTLD. An informant effect on the CDR has been reported in AD. The aim of this study is to evaluate whether informant characteristics influence the CDR PLUS NACC‐FTLD in a large cohort of participants with frontotemporal dementia (FTD). Method We included participants with a FTLD‐related syndrome from the ALLFTD study. We included participants with a CDR PLUS NACC‐FTLD higher than 0, information on the Montreal Cognitive Assessment (MoCA) scores, and the Neuropsychiatric Inventory Questionnaire (NPI‐Q). We performed a conditional growth model using multilevel linear regression analysis. We performed an exploratory stratified analysis by patient sex. Result We included 1411 participants, totalling 2063 visits. The patient's age at the initial visit was 64.7±9.4 years and 44.0% were females. Females were 69.2% of the informants, and the relationship was 79.1% spouse or partner, 10.6% children, 4.1% were siblings and 6.2% other. The CDR PLUS NACC‐FTLD scores were affected by informant characteristics. The CDR PLUS NACC‐FTLD scores were 0.41 (CI 95%:0.08 to 0.75) higher with female informants. The frequency of visits was associated with a CDR PLUS NACC‐FTLD score 0.86 higher (CI 95%:0.17 to 0.56) when visiting at least once a week, 1.46 higher (CI 95%:0.46 to 2.47) when visiting daily, and 0.83 higher (CI 95%:0.06 to 1.60) when living with the patient compared with visiting less than once a week. As expected, CDR‐FLTD scores increased with lower MoCA and higher NPI‐Q scores. In the stratified analysis by sex, we found that female informant was associated with higher CDR PLUS NACC‐FTLD scores only when patients were male. Conclusion We found that the CDR PLUS NACC‐FTLD is influenced by informant sex and frequency of visits in patients with FTLD‐related syndromes. These results are similar to those observed in AD patients and underscore the need to recognize that informant characteristics may impact dementia severity scales.

AbstractINTRODUCTIONHigher male prevalence in sporadic behavioral variant frontotemporal dementia (bvFTD) has been reported. We hypothesized differences in phenotypes between genetic and sporadic bvFTD females resulting in underdiagnosis of sporadic bvFTD females.METHODSWe included genetic and sporadic bvFTD patients from two multicenter cohorts. We compared behavioral and cognitive symptoms, and gray matter volumes, between genetic and sporadic cases in each sex.RESULTSFemales with sporadic bvFTD showed worse compulsive behavior (p = 0.026) and language impairments (p = 0.024) compared to females with genetic bvFTD (n = 152). Genetic bvFTD females had smaller gray matter volumes than sporadic bvFTD females, particularly in the parietal lobe.DISCUSSIONFemales with sporadic bvFTD exhibit a distinct clinical phenotype compared to females with genetic bvFTD. This difference may explain the discrepancy in prevalence between genetic and sporadic cases, as some females without genetic mutations may be misdiagnosed due to atypical bvFTD symptom presentation.Highlights Sex ratio is equal in genetic behavioral variant of frontotemporal dementia (bvFTD), whereas more males are present in sporadic bvFTD. Distinct neuropsychiatric phenotypes exist between sporadic and genetic bvFTD in females. Phenotype might explain the sex ratio difference between sporadic and genetic cases.

Abstract INTRODUCTION Sex differences are apparent in neurodegenerative diseases but have not been comprehensively characterized in frontotemporal dementia (FTD). METHODS Participants included 337 adults with autosomal dominant FTD enrolled in the ALLFTD Consortium. Clinical assessments and plasma were collected annually for up to 6 years. Linear mixed‐effects models investigated how sex and disease stage are associated with longitudinal trajectories of cognition, function, and neurofilament light chain (NfL). RESULTS While sex differences were not apparent at asymptomatic stages, females showed more rapid declines across all outcomes in symptomatic stages compared to males. In asymptomatic participants, the association between baseline NfL and clinical trajectories was weaker in females versus males, a difference that was not present in symptomatic participants. DISCUSSION In genetic FTD, females show cognitive resilience in early disease stages followed by steeper clinical declines later in the disease. Baseline NfL may be a less sensitive prognostic tool for clinical progression in females with FTD‐causing mutations. Highlights Females with genetic FTD exhibit overall steeper increases in plasma neurofilament light chain (NfL) than males. Females with genetic FTD outperform NfL levels in asymptomatic stages compared to males. Once symptomatic, females with genetic FTD decline more rapidly than males. Plasma NfL is a stronger prognostic marker in asymptomatic males than females.

Abstract The largest risk factor for dementia is age. Heterochronic blood exchange studies have uncovered age-related blood factors that demonstrate ‘pro-aging’ or ‘pro-youthful’ effects on the mouse brain. The clinical relevance and combined effects of these factors for humans is unclear. We examined five previously identified brain rejuvenation factors in cerebrospinal fluid of adults with autosomal dominant forms of frontotemporal dementia and sporadic Alzheimer’s disease. Our frontotemporal dementia cohort included 100 observationally followed adults carrying autosomal dominant frontotemporal dementia mutations (Mage = 49.6; 50% female; 43% C9orf72, 24% GRN, 33% MAPT) and 62 non-carriers (Mage = 52.6; 45% female) with cerebrospinal fluid analysed on Somascan, and longitudinal (Mvisits = 3 years, range 1–7 years) neuropsychological and functional assessments and plasma neurofilament light chain. Our Alzheimer’s disease cohort included 35 adults with sporadic Alzheimer’s disease (Mage = 69.4; 60% female) and 56 controls (Mage = 68.8, 50% female) who completed the same cerebrospinal fluid and clinical outcome measures cross-sectionally. Levels of C-C motif chemokine ligand 11, C-C motif chemokine ligand 2, beta-2-micorglobulin, bone gamma-carboxyglutamate protein (aka Osteocalcin) and colony stimulating factor 2 in cerebrospinal fluid were linearly combined into a composite score, with higher values reflecting ‘pro-youthful’ levels. In genetic frontotemporal dementia, higher baseline cerebrospinal fluid rejuvenation proteins predicted slower decline across cognitive, functional, and neurofilament light chain trajectories; estimates were similar across genotypes. In transdiagnostic analyses, higher cerebrospinal fluid rejuvenation proteins associated with better functional, cognitive, and neurofilament light chain outcomes in adults with sporadic Alzheimer’s disease. Proteins with pre-clinical evidence for brain rejuvenation show translational clinical relevance in adults with Alzheimer’s disease and related dementias and warrant further investigation.