Tau uptake in agrammatic primary progressive aphasia with and without apraxia of speech.

BACKGROUND AND PURPOSE: The non-fluent/agrammatic variant of primary progressive aphasia (agPPA) is a heterogeneous diagnosis wherein some individuals have apraxia of speech (AOS). When agPPA includes AOS, a tauopathy is the likely underlying pathology. Recently, [18F]AV-1451 was developed for the in-vivo assessment of tau. In this study, we compared patterns of tau tracer uptake in patients with agPPA with and without AOS. METHODS: Nine patients with agPPA (four without AOS) underwent tau positron emission tomography imaging with [18F]AV-1451. Uptake of [18F]AV-1451 was assessed as cortical to cerebellar crus ratio (standard uptake value ratio) in cortical regions of interest measured using the MCALT atlas and compared voxel-wise in SPM12. Each patient was age- and sex-matched to three controls. RESULTS: The agPPA without AOS showed uptake in the left frontal and temporal lobes, whereas agPPA with AOS showed uptake in the bilateral supplementary motor areas, frontal lobes, precuneus and precentral gyrus relative to controls. The left precentral gyrus had uptake in agPPA with AOS relative to those without AOS. CONCLUSIONS: This cross-sectional study suggests that [18F]AV-1451 uptake in the precentral gyrus is implicated in AOS in agPPA.

Association between exposure to anaesthesia and surgery and long-term cognitive trajectories in older adults: report from the Mayo Clinic Study of Aging.

BACKGROUND: The link between exposure to general anaesthesia and surgery (exposure) and cognitive decline in older adults is debated. We hypothesised that it is associated with cognitive decline. METHODS: We analysed the longitudinal cognitive function trajectory in a cohort of older adults. Models assessed the rate of change in cognition over time, and its association with exposure to anaesthesia and surgery. Analyses assessed whether exposure in the 20 yr before enrolment is associated with cognitive decline when compared with those unexposed, and whether post-enrolment exposure is associated with a change in cognition in those unexposed before enrolment. RESULTS: We included 1819 subjects with median (25th and 75th percentiles) follow-up of 5.1 (2.7-7.6) yr and 4 (3-6) cognitive assessments. Exposure in the previous 20 yr was associated with a greater negative slope compared with not exposed (slope: -0.077 vs -0.059; difference: -0.018; 95% confidence interval: -0.032, -0.003; P=0.015). Post-enrolment exposure in those previously unexposed was associated with a change in slope after exposure (slope: -0.100 vs -0.059 for post-exposure vs pre-exposure, respectively; difference: -0.041; 95% confidence interval: -0.074, -0.008; P=0.016). Cognitive impairment could be attributed to declines in memory and attention/executive cognitive domains. CONCLUSIONS: In older adults, exposure to general anaesthesia and surgery was associated with a subtle decline in cognitive z-scores. For an individual with no prior exposure and with exposure after enrolment, the decline in cognitive function over a 5 yr period after the exposure would be 0.2 standard deviations more than the expected decline as a result of ageing. This small cognitive decline could be meaningful for individuals with already low baseline cognition.

Clinicopathologic heterogeneity in frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) due to microtubule-associated protein tau (MAPT) p.P301L mutation, including a patient with globular glial tauopathy.

AIM: The p.P301L mutation in microtubule-associated protein tau (MAPT) is a common cause of frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17). We compare clinicopathologic features of five unrelated and three related (brother, sister and cousin) patients with FTDP-17 due to p.P301L mutation. METHODS: Genealogical, clinical, neuropathologic and genetic data were reviewed from eight individuals. RESULTS: The series consisted of five men and three women with an average age of death of 58 years (52-65 years) and average disease duration of 9 years (3-14 years). The first symptoms were those of behavioural variant frontotemporal dementia in seven patients and semantic variant of primary progressive aphasia in one. Three patients were homozygous for the MAPT H1 haplotype; five had H1/H2 genotype. The apolipoprotein E genotype was ϵ3/ϵ3 in seven and ϵ3/ϵ4 in one. The average brain weight was 1015 g (876-1188 g). All had frontotemporal lobar or more diffuse cortical atrophy. Except for one patient, the hippocampus and parahippocampal gyrus had minimal atrophy, whereas there was atrophy of middle and inferior temporal gyri. Dentate fascia neuronal dispersion was identified in three patients, two of whom had epilepsy. In one patient there was extensive white matter tau involvement with Gallyas-positive globular glial inclusions typical of globular glial tauopathy (GGT). CONCLUSIONS: This clinicopathologic study shows inter- and intra-familial clinicopathologic heterogeneity of FTDP-17 due to MAPT p.P301L mutation, including GGT in one patient.

Postoperative delirium in elderly patients is associated with subsequent cognitive impairment.

BACKGROUND: We examined the risk for postoperative delirium (POD) in patients with mild cognitive impairment (MCI) or dementia, and the association between POD and subsequent development of MCI or dementia in cognitively normal elderly patients. METHODS: Patients ≥65 yr of age enrolled in the Mayo Clinic Study of Aging who were exposed to any type of anaesthesia from 2004 to 2014 were included. Cognitive status was evaluated before and after surgery by neuropsychological testing and clinical assessment, and was defined as normal or MCI/dementia. Postoperative delirium was detected with the Confusion Assessment Method for the intensive care unit. Logistic regression analyses were performed. RESULTS: Among 2014 surgical patients, 74 (3.7%) developed POD. Before surgery, 1667 participants were cognitively normal, and 347 met MCI/dementia criteria. The frequency of POD was higher in patients with pre-existing MCI/dementia compared with no MCI/dementia {8.7 vs 2.6%; odds ratio (OR) 2.53, [95% confidence interval (CI) 1.52-4.21]; P <0.001}. Postoperative delirium was associated with lower education [OR, 3.40 (95% CI, 1.60-7.40); P =0.002 for those with <12 vs ≥16 yr of schooling]. Of the 1667 patients cognitively normal at their most recent assessment, 1152 returned for postoperative evaluation, and 109 (9.5%) met MCI/dementia criteria. The frequency of MCI/dementia at the first postoperative evaluation was higher in patients who experienced POD compared with those who did not [33.3 vs 9.0%; adjusted OR, 3.00 (95% CI, 1.12-8.05); P =0.029]. CONCLUSIONS: Mild cognitive impairment or dementia is a risk for POD. Elderly patients who have not been diagnosed with MCI or dementia but experience POD are more likely to be diagnosed subsequently with MCI or dementia.

HMGCR is a genetic modifier for risk, age of onset and MCI conversion to Alzheimer's disease in a three cohorts study.

Several retrospective epidemiological studies report that utilization of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) inhibitors called statins at mid-life can reduce the risk of developing sporadic Alzheimer's disease (AD) by as much as 70%. Conversely, the administration of these inhibitors in clinically diagnosed subjects with AD confers little or no benefits over time. Here, we investigated the association between AD and HMGCR rs3846662, a polymorphism known to be involved in the regulation of HMGCR exon 13 skipping, in a founder population and in two distinct mixed North American populations of converting mild cognitively impaired (MCI) subjects (Alzheimer's disease Cooperative study (ADCS) and Alzheimer's disease Neuroimaging Initiative (ADNI) cohorts). Targeting more specifically women, the G allele negative (G-) AD subjects exhibit delayed age of onset of AD (P=0.017) and significantly reduced risk of AD (OR: 0.521; P=0.0028), matching the effect size reported by the apolipoprotein E type 2 variant. Stratification for APOE4 in a large sample of MCI patients from the ADCS cohort revealed a significant protective effect of G negative carriers on AD conversion 3 years after MCI diagnosis (odds ratio (OR): 0.554; P=0.041). Conversion rate among APOE4 carriers with the HMGCR's G negative allele was markedly reduced (from 76% to 27%) to levels similar to APOE4 non-carriers (27.14%), which strongly indicate protection. Conversion data from the independent ADNI cohort also showed significantly reduced MCI or AD conversion among APOE4 carriers with the protective A allele (P=0.005). In conclusion, HMGCR rs3846662 acts as a potent genetic modifier for AD risk, age of onset and conversion.

FASTKD2 is associated with memory and hippocampal structure in older adults.

Memory impairment is the cardinal early feature of Alzheimer's disease, a highly prevalent disorder whose causes remain only partially understood. To identify novel genetic predictors, we used an integrative genomics approach to perform the largest study to date of human memory (n=14 781). Using a genome-wide screen, we discovered a novel association of a polymorphism in the pro-apoptotic gene FASTKD2 (fas-activated serine/threonine kinase domains 2; rs7594645-G) with better memory performance and replicated this finding in independent samples. Consistent with a neuroprotective effect, rs7594645-G carriers exhibited increased hippocampal volume and gray matter density and decreased cerebrospinal fluid levels of apoptotic mediators. The MTOR (mechanistic target of rapamycin) gene and pathways related to endocytosis, cholinergic neurotransmission, epidermal growth factor receptor signaling and immune regulation, among others, also displayed association with memory. These findings nominate FASTKD2 as a target for modulating neurodegeneration and suggest potential mechanisms for therapies to combat memory loss in normal cognitive aging and dementia.

APOE and BCHE as modulators of cerebral amyloid deposition: a florbetapir PET genome-wide association study.

Deposition of amyloid-ß (Aß) in the cerebral cortex is thought to be a pivotal event in Alzheimer's disease (AD) pathogenesis with a significant genetic contribution. Molecular imaging can provide an early noninvasive phenotype, but small samples have prohibited genome-wide association studies (GWAS) of cortical Aß load until now. We employed florbetapir ((18)F) positron emission tomography (PET) imaging to assess brain Aß levels in vivo for 555 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI). More than six million common genetic variants were tested for association to quantitative global cortical Aß load controlling for age, gender and diagnosis. Independent genome-wide significant associations were identified on chromosome 19 within APOE (apolipoprotein E) (rs429358, P=5.5 × 10(-14)) and on chromosome 3 upstream of BCHE (butyrylcholinesterase) (rs509208, P=2.7 × 10(-8)) in a region previously associated with serum BCHE activity. Together, these loci explained 15% of the variance in cortical Aß levels in this sample (APOE 10.7%, BCHE 4.3%). Suggestive associations were identified within ITGA6, near EFNA5, EDIL3, ITGA1, PIK3R1, NFIB and ARID1B, and between NUAK1 and C12orf75. These results confirm the association of APOE with Aß deposition and represent the largest known effect of BCHE on an AD-related phenotype. BCHE has been found in senile plaques and this new association of genetic variation at the BCHE locus with Aß burden in humans may have implications for potential disease-modifying effects of BCHE-modulating agents in the AD spectrum.

Brain atrophy over time in genetic and sporadic frontotemporal dementia: a study of 198 serial magnetic resonance images.

BACKGROUND AND PURPOSE: The aim of our study was to determine the utility of longitudinal magnetic resonance imaging (MRI) measurements as potential biomarkers in the main genetic variants of frontotemporal dementia (FTD), including microtubule-associated protein tau (MAPT) and progranulin (GRN) mutations and C9ORF72 repeat expansions, as well as sporadic FTD. METHODS: In this longitudinal study, 58 subjects were identified who had at least two MRI and MAPT mutations (n = 21), GRN mutations (n = 11), C9ORF72 repeat expansions (n = 11) or sporadic FTD (n = 15). A total of 198 serial MRI measurements were analyzed. Rates of whole brain atrophy were calculated using the boundary shift integral. Regional rates of atrophy were calculated using tensor-based morphometry. Sample size estimates were calculated. RESULTS: Progressive brain atrophy was observed in all groups, with fastest rates of whole brain atrophy in GRN, followed by sporadic FTD, C9ORF72 and MAPT. All variants showed greatest rates in the frontal and temporal lobes, with parietal lobes also strikingly affected in GRN. Regional rates of atrophy across all lobes were greater in GRN compared to the other groups. C9ORF72 showed greater rates of atrophy in the left cerebellum and right occipital lobe than MAPT, and sporadic FTD showed greater rates in the anterior cingulate than C9ORF72 and MAPT. Sample size estimates were lowest using temporal lobe rates in GRN, ventricular rates in MAPT and C9ORF72, and whole brain rates in sporadic FTD. CONCLUSION: These data support the utility of using rates of atrophy as outcome measures in future drug trials in FTD and show that different imaging biomarkers may offer advantages in the different variants of FTD.

DNAJC13 p.Asn855Ser mutation screening in Parkinson's disease and pathologically confirmed Lewy body disease patients.

BACKGROUND: Recently, a novel mutation in exon 24 of DNAJC13 gene (p.Asn855Ser, rs387907571) has been reported to cause autosomal dominant Parkinson's disease (PD) in a multi-incident Mennonite family. METHODS: In the present study the mutation containing exon of the DNAJC13 gene has been sequenced in a Caucasian series consisting of 1938 patients with clinical PD and 838 with pathologically diagnosed Lewy body disease (LBD). RESULTS: Our sequence analysis did not identify any coding variants in exon 24 of DNAJC13. Two previously described variants in intron 23 (rs200204728 and rs2369796) were observed. CONCLUSION: Our results indicate that the region surrounding the DNAJC13 p.Asn855Ser substitution is highly conserved and mutations in this exon are not a common cause of PD or LBD among Caucasian populations.

Mild cognitive impairment: a concept in evolution.

The construct of mild cognitive impairment (MCI) has evolved over the past 10 years since the publication of the new MCI definition at the Key Symposium in 2003, but the core criteria have remained unchanged. The construct has been extensively used worldwide, both in clinical and in research settings, to define the grey area between intact cognitive functioning and clinical dementia. A rich set of data regarding occurrence, risk factors and progression of MCI has been generated. Discrepancies between studies can be mostly explained by differences in the operationalization of the criteria, differences in the setting where the criteria have been applied, selection of subjects and length of follow-up in longitudinal studies. Major controversial issues that remain to be further explored are algorithmic versus clinical classification, reliability of clinical judgment, temporal changes in cognitive performances and predictivity of putative biomarkers. Some suggestions to further develop the MCI construct include the tailoring of the clinical criteria to specific populations and to specific contexts. The addition of biomarkers to the clinical phenotypes is promising but requires deeper investigation. Translation of findings from the specialty clinic to the population setting, although challenging, will enhance uniformity of outcomes. More longitudinal population-based studies on cognitive ageing and MCI need to be performed to clarify all these issues.

Whole-exome sequencing and imaging genetics identify functional variants for rate of change in hippocampal volume in mild cognitive impairment.

Whole-exome sequencing of individuals with mild cognitive impairment, combined with genotype imputation, was used to identify coding variants other than the apolipoprotein E (APOE) ε4 allele associated with rate of hippocampal volume loss using an extreme trait design. Matched unrelated APOE ε3 homozygous male Caucasian participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) were selected at the extremes of the 2-year longitudinal change distribution of hippocampal volume (eight subjects with rapid rates of atrophy and eight with slow/stable rates of atrophy). We identified 57 non-synonymous single nucleotide variants (SNVs) which were found exclusively in at least 4 of 8 subjects in the rapid atrophy group, but not in any of the 8 subjects in the slow atrophy group. Among these SNVs, the variants that accounted for the greatest group difference and were predicted in silico as 'probably damaging' missense variants were rs9610775 (CARD10) and rs1136410 (PARP1). To further investigate and extend the exome findings in a larger sample, we conducted quantitative trait analysis including whole-brain search in the remaining ADNI APOE ε3/ε3 group (N=315). Genetic variation within PARP1 and CARD10 was associated with rate of hippocampal neurodegeneration in APOE ε3/ε3. Meta-analysis across five independent cross sectional cohorts indicated that rs1136410 is also significantly associated with hippocampal volume in APOE ε3/ε3 individuals (N=923). Larger sequencing studies and longitudinal follow-up are needed for confirmation. The combination of next-generation sequencing and quantitative imaging phenotypes holds significant promise for discovery of variants involved in neurodegeneration.

A Pragmatic, Investigator-Driven Process for Disclosure of Amyloid PET Scan Results to ADNI-4 Research Participants.

BACKGROUND: Prior studies of Alzheimer's disease (AD) biomarker disclosure have answered important questions about individuals' safety after learning and comprehending their amyloid PET results; however, these studies have typically employed highly structured disclosure protocols and focused on the psychological impact of disclosure (e.g., anxiety, depression, and suicidality) in homogeneous populations. More work is needed to develop flexible disclosure protocols and study outcomes in ethnoculturally representative samples. METHODS: The Alzheimer's Disease Neuroimaging Initiative (ADNI) is formally incorporating amyloid PET disclosure into the newest protocol (ADNI-4). Participants across the cognitive spectrum who wish to know their amyloid PET results may learn them. The pragmatic disclosure process spans four timepoints: (1) a pre-disclosure visit, (2) the PET scan and its read, (3) a disclosure visit, and (4) a post-disclosure check-in. This process applies to all participants, with slight modifications to account for their cognitive status. In designing this process, special emphasis was placed on utilizing investigator discretion. Participant measures include perceived risk of dementia, purpose in life, and disclosure satisfaction. Investigator assessment of the disclosure visit (e.g., challenges encountered, topics discussed, etc.) is also included. RESULTS: Data collection is ongoing. Results will allow for more robust characterization of the impact of learning amyloid PET results on individuals and describe the perspectives of investigators. CONCLUSION: The pragmatic design of the disclosure process in ADNI-4 coupled with the novel participant and investigator data will inform future disclosure practices. This is especially important as disclosure of biomarker results expands in research and care.

Midbrain atrophy is not a biomarker of progressive supranuclear palsy pathology.

BACKGROUND AND PURPOSE: Midbrain atrophy is a characteristic feature of progressive supranuclear palsy (PSP), although it is unclear whether it is associated with the PSP syndrome (PSPS) or PSP pathology. The aim of the present study was to determine whether midbrain atrophy is a useful biomarker of PSP pathology, or whether it is only associated with typical PSPS. METHODS: All autopsy-confirmed subjects were identified with the PSP clinical phenotype (i.e. PSPS) or PSP pathology and a volumetric MRI. Of 24 subjects with PSP pathology, 11 had a clinical diagnosis of PSPS (PSP-PSPS), and 13 had a non-PSPS clinical diagnosis (PSP-other). Three subjects had PSPS and corticobasal degeneration pathology (CBD-PSPS). Healthy control and disease control groups (i.e. a group without PSPS or PSP pathology) and a group with CBD pathology and corticobasal syndrome (CBD-CBS) were selected. The midbrain area was measured in all subjects. [Correction added on 21 June 2013, after first online publication: the abbreviation of corticobasal degeneration pathology was changed from CBD-PSP to CBD-PSPS.] RESULTS: The midbrain area was reduced in each group with clinical PSPS (with and without PSP pathology). The group with PSP pathology and non-PSPS clinical syndromes did not show reduced midbrain area. Midbrain area was smaller in the subjects with PSPS than in those without PSPS (P < 0.0001), with an area under the receiver operator curve of 0.99 (0.88, 0.99). A midbrain area cut-point of 92 mm(2) provided optimum sensitivity (93%) and specificity (89%) for differentiation. CONCLUSION: Midbrain atrophy is associated with the clinical presentation of PSPS, but not with the pathological diagnosis of PSP in the absence of clinical PSPS. This finding has important implications for the utility of midbrain measurements as diagnostic biomarkers for PSP pathology.

Lecanemab: Appropriate Use Recommendations.

Lecanemab (Leqembi®) is approved in the United States for the treatment of Alzheimer's disease (AD) to be initiated in early AD (mild cognitive impairment [MCI] due to AD or mild AD dementia) with confirmed brain amyloid pathology. Appropriate Use Recommendations (AURs) are intended to help guide the introduction of new therapies into real-world clinical practice. Community dwelling patients with AD differ from those participating in clinical trials. Administration of lecanemab at clinical trial sites by individuals experienced with monoclonal antibody therapy also differs from the community clinic-based administration of lecanemab. These AURs use clinical trial data as well as research and care information regarding AD to help clinicians administer lecanemab with optimal safety and opportunity for effectiveness. Safety and efficacy of lecanemab are known only for patients like those participating in the phase 2 and phase 3 lecanemab trials, and these AURs adhere closely to the inclusion and exclusion criteria of the trials. Adverse events may occur with lecanemab including amyloid related imaging abnormalities (ARIA) and infusion reactions. Monitoring guidelines for these events are detailed in this AUR. Most ARIA with lecanemab is asymptomatic, but a few cases are serious or, very rarely, fatal. Microhemorrhages and rare macrohemorrhages may occur in patients receiving lecanemab. Anticoagulation increases the risk of hemorrhage, and the AUR recommends that patients requiring anticoagulants not receive lecanemab until more data regarding this interaction are available. Patients who are apolipoprotein E ε4 (APOE4) gene carriers, especially APOE4 homozygotes, are at higher risk for ARIA, and the AUR recommends APOE genotyping to better inform risk discussions with patients who are lecanemab candidates. Clinician and institutional preparedness are mandatory for use of lecanemab, and protocols for management of serious events should be developed and implemented. Communication between clinicians and therapy candidates or those on therapy is a key element of good clinical practice for the use of lecanemab. Patients and their care partners must understand the potential benefits, the potential harms, and the monitoring requirements for treatment with this agent. Culture-specific communication and building of trust between clinicians and patients are the foundation for successful use of lecanemab.

Voxel-based morphometry in patients with obsessive-compulsive behaviors in behavioral variant frontotemporal dementia.

BACKGROUND AND PURPOSE: Obsessions and compulsive (OC) behaviors are a frequent feature of behavioral variant frontotemporal dementia (bvFTD), but their structural correlates have not been definitively established. METHODS: Patients with bvFTD presenting to the Mayo Clinic Alzheimer's Disease Research Center were recruited. Each patient's caregiver was given the Yale-Brown Obsessive-Compulsive scale (YBOCS) to document the type and presence of OC behaviors and to rate their severity. All subjects underwent standardized magnetic resonance imaging (MRI) that was evaluated using voxel-based morphometry (VBM). Seventeen patients with bvFTD were recruited, and 11 were included in the study and compared with 11 age- and gender-matched controls. Six were excluded for lack of MRI at the time of survey or a pre-existing neurodegenerative condition. RESULTS: Nine of the 11 reported OC behaviors, with the most frequent compulsions being checking, hoarding, ordering/arranging, repeating rituals, and cleaning. In the VBM analysis, total YBOCS score correlated with gray matter loss in the bilateral globus pallidus, left putamen, and in the lateral temporal lobe, particularly the left middle and inferior temporal gyri (P < 0.001 uncorrected for multiple comparisons). CONCLUSIONS: Obsessive-compulsive behaviors were frequent among these patients. The correlation with basal ganglia atrophy may point to involvement of frontal subcortical neuronal networks. Left lateral temporal lobe volume loss probably reflects the number of MAPT mutation patients included but also provides additional data implicating temporal lobe involvement in OC behaviors.

Senolytic Therapy to Modulate the Progression of Alzheimer's Disease (SToMP-AD): A Pilot Clinical Trial.

Preclinical studies indicate an age-associated accumulation of senescent cells across multiple organ systems. Emerging evidence suggests that tau protein accumulation, which closely correlates with cognitive decline in Alzheimer's disease and other tauopathies, drives cellular senescence in the brain. Pharmacologically clearing senescent cells in mouse models of tauopathy reduced brain pathogenesis. Compared to vehicle treated mice, intermittent senolytic administration reduced tau accumulation and neuroinflammation, preserved neuronal and synaptic density, restored aberrant cerebral blood flow, and reduced ventricular enlargement. Intermittent dosing of the senolytics, dasatinib plus quercetin, has shown an acceptable safety profile in clinical studies for other senescence-associated conditions. With these data, we proposed and herein describe the objectives and methods for a clinical vanguard study. This initial open-label clinical trial pilots an intermittent senolytic combination therapy of dasatinib plus quercetin in five older adults with early-stage Alzheimer's disease. The primary objective is to evaluate the central nervous system penetration of dasatinib and quercetin through analysis of cerebrospinal fluid collected at baseline and after 12 weeks of treatment. Further, through a series of secondary outcome measures to assess target engagement of the senolytic compounds and Alzheimer's disease-relevant cognitive, functional, and physical outcomes, we will collect preliminary data on safety, feasibility, and efficacy. The results of this study will be used to inform the development of a randomized, double-blind, placebo-controlled multicenter phase II trial to further explore of the safety, feasibility, and efficacy of senolytics for modulating the progression of Alzheimer's disease. Clinicaltrials.gov registration number and date: NCT04063124 (08/21/2019).

Alzheimer's Disease Clinical Trial Research Adaptation Following COVID-19 Pandemic Onset: National Sample of Alzheimer's Clinical Trial Consortium Sites.

BACKGROUND: The COVID-19 pandemic created challenges in clinical research operations that required immediate and lasting changes. OJBECTIVES: The purpose of this study was to explore adaptations to clinical trial research due to COVID-19 and develop a theoretical framework of emergent strategies related to pandemic mitigation in a national network of Alzheimer's disease clinical trial sites. DESIGN: This qualitative study used a grounded theory approach including semi-structured interviews, constant comparative methods, and multi-level, iterative coding. PARTICIPANTS: Twenty-six member sites of the Alzheimer's Clinical Trial Consortium participated with a total of 49 participants. RESULTS: Findings demonstrate processes of adaptation following COVID-19 onset including establishing safety as priority, focus on scientific preservation, accommodations (creating policies, leadership mindset, maintaining operations, and determining research procedures), and evaluation of changes throughout the course of the pandemic. Communication and maintaining integrity were vital throughout these processes. CONCLUSION: Processes of accommodation among clinical research sites during the pandemic provide critical insights and direction for future clinical trials development and emergent methods in Alzheimer's disease and other therapeutic areas.

Application of Digital Cognitive Biomarkers for Alzheimer's Disease: Identifying Cognitive Process Changes and Impending Cognitive Decline.

BACKGROUND: Recent Alzheimer's disease (AD) trials have faced significant challenges to enroll pre-symptomatic or early stage AD subjects with biomarker positivity, minimal or no cognitive impairment, and likelihood to decline cognitively during a short trial period. Our previous study showed that digital cognitive biomarkers (DCB), generated by a hierarchical Bayesian cognitive process (HBCP) model, were able to distinguish groups of cognitively normal individuals with impending cognitive decline from those without. We generated DCBs using only baseline Auditory Verbal Learning Test's wordlist memory (WLM) item response data from the Mayo Clinic Alzheimer's Disease Patient Registry. OBJECTIVES: To replicate our previous findings, using baseline ADAS-Cog WLM item response data from the Alzheimer's Disease Neuroimaging Initiative, and compare DCBs to traditional approaches for scoring word-list memory tests. DESIGN: Classified decliner subjects (n = 61) as those who developed amnestic MCI or AD dementia within 3 years of normal baseline assessment and non-decliner (n = 442) as those who did not. MEASURES: Evaluated the relative value of DCBs compared to traditional measures, using three analytic approaches to group differences: 1) logistic regression of summary scores per ADAS-Cog WLM task; 2) Bayesian modeling of summary scores; and 3) HBCP modeling to generate DCBs from item-level responses. RESULTS: The HBCP model produced posterior distributions of group differences, of which Bayes factor assessment identified three DCBs with notable group differences: Immediate Retrieval from Durable Storage, (BFds = 11.8, strong evidence); One-Shot Learning, (BFds = 4.5, moderate evidence); and Partial Learning (BFds = 2.9, weak evidence). In contrast, logistic regression of summary scores did not significantly discriminate between groups, and the Bayes factor assessment of modeled summary scores provided moderate evidence that the groups were equivalent (BFsd = 3.4, 3.1, 2.9, and 1.4, respectively). CONCLUSIONS: This study demonstrated DCBs' ability to distinguish , at baseline, between impending cognitive decline and non-decline groups where individuals in both groups were classified as cognitively normal. This validated findings from our previous study, demonstrating DCBs' advantages over traditional approaches. This study warrants further refinement of the HBCP DCBs to predict impending cognitive decline in individuals and other factors associated with AD, such as physical biomarker load.

Caudate atrophy on MRI is a characteristic feature of FTLD-FUS.

BACKGROUND AND PURPOSE: Frontotemporal lobar degeneration (FTLD) can be subdivided into those in which the abnormal protein is tau (FTLD-TAU), the TAR DNA binding protein 43 (FTLD-TDP) and the fused in sarcoma protein (FTLD-FUS). We have observed severe caudate atrophy at autopsy in FTLD-FUS, and hence, we aimed to determine whether caudate atrophy on MRI is a feature that can distinguish FTLD-FUS from FTLD-TDP and FTLD-TAU. METHODS: From a cohort of 207 cases of FTLD, we identified all cases of FTLD-FUS that had a volumetric antemortem head MRI (n = 3). Caudate and frontal lobe volumes were measured in all three cases using atlas-based parcellation and SPM5 and were compared to 10 randomly selected cases of FTLD-TDP and 10 randomly selected cases of FTLD-TAU. Total grey matter volumes were also calculated for all cases. RESULTS: The FTLD-FUS cases had significantly smaller caudate volumes (P = 0.02) yet similar frontal lobe grey matter volumes (P = 0.12) compared to FTLD-TDP and FTLD-TAU. Caudate volumes when corrected for total grey matter volume (P = 0.01) or frontal lobe grey matter volume (P = 0.01) were significantly smaller in FTLD-FUS than in FTLD-TDP and FTLD-TAU and showed no overlap with the other two groups. CONCLUSIONS: Caudate atrophy on MRI appears to be significantly greater in FTLD-FUS compared with FTLD-TDP and FTLD-TAU, suggesting that severe caudate atrophy may be a useful clinical feature to predict FTLD-FUS pathology.

Longitudinal Comparison of in Clinic and at Home Administration of the Cogstate Brief Battery and Demonstrated Practice Effects in the Mayo Clinic Study of Aging.

BACKGROUND: The Cogstate Brief Battery (CBB) is a computerized cognitive assessment that can be completed in clinic or at home. Design/Objective: This retrospective study investigated whether practice effects / performance trajectories of the CBB differ by location of administration. PARTICIPANTS/SETTING: Participants included 1439 cognitively unimpaired individuals age 50-75 at baseline participating in the Mayo Clinic Study of Aging (MCSA), a population-based study of cognitive aging. Sixty three percent of participants completed the CBB in clinic only and 37% completed CBB both in clinic and at home. MEASUREMENTS: The CBB consists of four subtests: Detection, Identification, One Card Learning, and One Back. Linear mixed effects models were used to evaluate performance trajectories in clinic and at home. RESULTS: Results demonstrated significant practice effects between sessions 1 to 2 for most CBB measures. Practice effects continued over subsequent testing sessions, to a lesser degree. Average practice effects/trajectories were similar for each location (home vs. clinic). One Card Learning and One Back accuracy performances were lower at home than in clinic, and this difference was large in magnitude for One Card Learning accuracy. Participants performed faster at home on Detection reaction time, although this difference was small in magnitude. CONCLUSIONS: Results suggest the location where the CBB is completed has an important impact on performance, particularly for One Card Learning accuracy, and there are practice effects across repeated sessions that are similar regardless of where testing is completed.