Prevalence of amyloid-β pathology in distinct variants of primary progressive aphasia

OBJECTIVE

To estimate the prevalence of amyloid positivity, defined by positron emission tomography (PET)/cerebrospinal fluid (CSF) biomarkers and/or neuropathological examination, in primary progressive aphasia (PPA) variants.

METHODS

We conducted a meta-analysis with individual participant data from 1,251 patients diagnosed with PPA (including logopenic [lvPPA, n = 443], nonfluent [nfvPPA, n = 333], semantic [svPPA, n = 401], and mixed/unclassifiable [n = 74] variants of PPA) from 36 centers, with a measure of amyloid-β pathology (CSF [n = 600], PET [n = 366], and/or autopsy [n = 378]) available. The estimated prevalence of amyloid positivity according to PPA variant, age, and apolipoprotein E (ApoE) ε4 status was determined using generalized estimating equation models.

RESULTS

Amyloid-β positivity was more prevalent in lvPPA (86%) than in nfvPPA (20%) or svPPA (16%; p < 0.001). Prevalence of amyloid-β positivity increased with age in nfvPPA (from 10% at age 50 years to 27% at age 80 years, p < 0.01) and svPPA (from 6% at age 50 years to 32% at age 80 years, p < 0.001), but not in lvPPA (p = 0.94). Across PPA variants, ApoE ε4 carriers were more often amyloid-β positive (58.0%) than noncarriers (35.0%, p < 0.001). Autopsy data revealed Alzheimer disease pathology as the most common pathologic diagnosis in lvPPA (76%), frontotemporal lobar degeneration-TDP-43 in svPPA (80%), and frontotemporal lobar degeneration-TDP-43/tau in nfvPPA (64%).

INTERPRETATION

This study shows that the current PPA classification system helps to predict underlying pathology across different cohorts and clinical settings, and suggests that age and ApoE genotype should be considered when interpreting amyloid-β biomarkers in PPA patients. Ann Neurol 2018;84:737-748.

Validation of the Dépistage Cognitif de Québec: A New Cognitive Screening Tool for Atypical Dementias

Objective

This study aimed to validate and provide normative data for the Dépistage Cognitif de Québec (DCQ; www.dcqtest.org), a new cognitive screening tool for atypical dementias.

Method

The DCQ was developed by expert behavioral neurologists and clinical neuropsychologists based on updated criteria for Alzheimer's disease, primary progressive aphasia, and behavioral variant frontotemporal dementia. It targets five relevant domains: Memory, Visuospatial, Executive, Language, and Behavior. Validation was performed in a population-based sample of 410 healthy French-speaking Canadians aged between 50 and 89 years old. Normative data were derived from a subsample of 285 participants.

Results

Mean DCQ total score (out of 100) was 89.17 (SD = 7.36). Pearson's correlation coefficient showed a strong and significant correlation (r = .71, p < .001) with the Montreal Cognitive Assessment. Internal consistency for the cognitive domains assessed by Cronbach's alpha was satisfactory (.74). Test-retest reliability was adequate (Pearson's coefficient = . 70, p < .001) and interrater reliability, excellent (intraclass correlation = .99, p < .001). Normative data shown in percentiles were stratified by age and education.

Conclusions

This study suggests that the DCQ is a valid and reliable cognitive screening test. Application of the DCQ on populations with atypical dementias is underway to derive sensitivity and specificity values for various dementias.

Impact of a Student-Driven, Virtual Patient Application on Objective Structured Clinical Examination Performance: Observational Study

Background

Peer-assisted learning (PAL) refers to a learning activity whereby students of similar academic level teach and learn from one another. Groupe de perfectionnement des habiletés cliniques (Clinical Skills Improvement Group), a student organization at Université Laval, Canada, propelled PAL into the digital era by creating a collaborative virtual patient platform. Medical interviews can be completed in pairs (a student-patient and a student-doctor) through an interactive Web-based application, which generates a score (weighted for key questions) and automated feedback.

Objectives

The aim of the study was to measure the pedagogical impact of the application on the score at medical interview stations at the summative preclerkship Objective Structured Clinical Examination (OSCE).

Methods

We measured the use of the application (cases completed, mean score) in the 2 months preceding the OSCE. We also accessed the results of medical interview stations at the preclerkship summative OSCE. We analyzed whether using the application was associated with higher scores and/or better passing grades (≥60%) at the OSCE. Finally, we produced an online form where students could comment on their appreciation of the application.

Results

Of the 206 students completing the preclerkship summative OSCE, 170 (82.5%) were registered users on the application, completing a total of 3133 cases (18 by active user in average, 7 minutes by case in average). The appreciation questionnaire was answered online by 45 students who mentioned appreciating the intuitive, easy-to-use, and interactive design, the diversity of cases, and the automated feedback. Using the application was associated with reduced reported stress, improved scores (P=.04), and improved passing rates (P=.11) at the preclerkship summative OSCE.

Conclusions

This study suggests that PAL can go far beyond small-group teaching, showing students’ potential to create helpful pedagogical tools for their peers.

Finger-to-Nose Test Findings in Alzheimer's Disease

The finger-to-nose test is routinely performed during the clinical assessment of patients with cognitive impairments. Although widely known to screen for cerebellar dysfunction by unmasking appendicular ataxia, we have found that this test could also be interpreted from a cognitive perspective. We describe two typical signs observed at the finger-to-nose test in Alzheimer's disease (AD) patients: the "second finger syndrome" and the "distal pressure sign". By retrospectively reviewing the medical records 461 patients followed at our academic memory clinic, we found that these signs are commonplace in AD, but not in vascular dementia or subjective cognitive impairment.

Smartphone Usage Patterns by Canadian Neurosurgery Residents: A National Cross-Sectional Survey

BACKGROUND

Smartphones and their apps are used ubiquitously in medical practice. However, in some cases their use can be at odds with current patient data safety regulations such as Canada's Personal Health Information Protection Act of 2004. To assess current practices and inform mobile application development, we sought to better understand mobile device usage patterns among Canadian neurosurgery residents.

METHODS

Through the Canadian Neurosurgery Research Collaborative, an online survey characterizing smartphone ownership and usage patterns was developed and sent to all Canadian neurosurgery resident in April of 2016. Questionnaires were collected and completed surveys analyzed.

RESULTS

Of 146 eligible residents, 76 returned completed surveys (52% response rate). Of these 99% of respondents owned a smartphone, with 79% running on Apple's iOS. Four general mobile uses were identified: 1) communication between members of the medical team, 2) decision support, 3) medical reference, and 4) documentation through medical photography. Communication and photography were areas where the most obvious breaches in the Canadian Personal Health Information Protection Act were noted, with 89% of respondents taking pictures of patients' radiologic studies and 75% exchanging them with Short Message System. Hospital policies had no impact on user behaviors.

CONCLUSIONS

Smartphones are used daily by most neurosurgery residents. Identified usage patterns are associated with perceived gains in efficacy and challenges in privacy and data reliability. We believe creating and improving workflows that address these usage patterns has a greater potential to improve privacy than changing policies and enforcing regulations.

Clinical Utility of Amyloid PET Imaging in the Differential Diagnosis of Atypical Dementias and Its Impact on Caregivers

Recent studies have supported a role for amyloid positron emission tomography (PET) imaging in distinguishing Alzheimer's disease (AD) pathology from other pathological protein accumulations leading to dementia. We investigated the clinical utility of amyloid PET in the differential diagnosis of atypical dementia cases and its impact on caregivers. Using the amyloid tracer 18F-NAV4694, we prospectively scanned 28 patients (mean age 59.3 y, s.d. 5.8; mean MMSE 21.4, s.d. 6.0) with an atypical dementia syndrome. Following a comprehensive diagnostic workup (i.e., history taking, neurological examination, blood tests, neuropsychological evaluation, MRI, and FDG-PET), no certain diagnosis could be arrived at. Amyloid PET was then conducted and classified as positive or negative. Attending physicians were asked to evaluate whether this result led to a change in diagnosis or altered management. They also reported their degree of confidence in the diagnosis. Caregivers were met after disclosure of amyloid PET results and completed a questionnaire/interview to assess the impact of the scan. Our cohort was evenly divided between positive (14/28) and negative (14/28) 18F-NAV4694 cases. Amyloid PET resulted in a diagnostic change in 9/28 cases (32.1%: 17.8% changed from AD to non-AD, 14.3% from non-AD to AD). There was a 44% increase in diagnostic confidence. Altered management occurred in 71.4% (20/28) of cases. Knowledge of amyloid status improved caregivers' outcomes in all domains (anxiety, depression, disease perception, future anticipation, and quality of life). This study suggests a useful additive role for amyloid PET in atypical cases with an unclear diagnosis beyond the extensive workup of a tertiary memory clinic. Amyloid PET increased diagnostic confidence and led to clinically significant alterations in management. The information gained from that test was well received by caregivers and encouraged spending quality time with their loved ones.

Cognition and anatomy of adult Niemann-Pick disease type C: Insights for the Alzheimer field

Niemann-Pick disease type C (NPC) is a rare lysosomal storage disorder causing an intracellular lipid trafficking defect and varying damage to the spleen, liver, and central nervous system. The adult form, representing approximately 20% of the cases, is associated with progressive cognitive decline. Intriguingly, brains of adult NPC patients exhibit neurofibrillary tangles, a characteristic hallmark of Alzheimer's disease (AD). However, the cognitive, psychiatric, and neuropathological features of adult NPC and their relation to AD have yet to be explored. We systematically reviewed the literature on adult NPC with a particular focus on cognitive and neuroanatomical abnormalities. The careful study of cognition in adult NPC allows drawing critical insights in our understanding of the pathophysiology of AD as well as normal cognition.

Multicenter Validation of an MMSE-MoCA Conversion Table

BACKGROUND

Accumulating evidence points to the superiority of the MoCA over the MMSE as a cognitive screening tool. To facilitate the transition from the MMSE to the MoCA in clinical and research settings, authors have developed MMSE-MoCA conversion tables. However, it is unknown whether a conversion table generated from Alzheimer's disease (AD) patients would apply to patients with other dementia subtypes like vascular dementia or frontotemporal dementia. Furthermore, the reliability and accuracy of MMSE-MoCA conversion tables has not been properly evaluated.

METHOD

We retrospectively examined the MMSE-MoCA relationship in a large multicenter sample gathered from 3 Memory Clinics in Quebec, Canada (1492 patients). We produced an MMSE-MoCA conversion table using the equi-percentile method with log-linear smoothing. We then cross-validated our conversion table with the ADNI dataset (1202 patients) and evaluated its accuracy for future predictions.

RESULTS

The MMSE-MoCA conversion table is consistent with previously published tables and has an intra-class correlation of 0.633 with the ADNI sample. However, we found that the MMSE-MoCA relationship is significantly modified by diagnosis (P < .01), with dementia subtypes associated with a dysexecutive syndrome showing a trend towards higher MMSE than other dementia syndromes for a given MoCA score. The large width of 95% confidence interval (CI) for a new prediction suggests questionable reliability for clinical use.

CONCLUSION

In this study, we validated a conversion table between MMSE and MoCA using a large multicenter sample. Our results suggest caution in interpreting the tables in heterogeneous clinical populations, as the MMSE-MoCA relationship may be different across dementia subtypes.

Activity measurements of the radionuclides 18F and 64Cu for the NIST, USA in the ongoing comparisons BIPM.RI(II)-K4.F-18 and BIPM.RI(II)-K4.Cu-64

In 2016, comparisons of activity measurements of 18F and 64Cu using the Transfer Instrument of the International Reference System (SIRTI) took place at the National Institute of Standards and Technology (NIST, USA). This is the first SIRTI comparison for 64Cu. Ampoules containing about 27 kBq of 18F and 100 kBq of 64Cu solutions were measured in the SIRTI for about 5 and 1.5 half-lives, respectively. The NIST standardized the activity in the ampoules by ionization chamber measurements traceable to 4π(LS)β-γ anticoincidence measurements. The comparisons, identifiers BIPM.RI(II)-K4.F-18 and BIPM.RI(II)-K4.Cu-64, are linked to the corresponding BIPM.RI(II)-K1.F-18 and BIPM.RI(II)-K1.Cu-64 comparisons and degrees of equivalence with the respective key comparison reference values have been evaluated. The NIST replaces its earlier degree of equivalence for 18F obtained in the frame of the CCRI(II)-K3.F-18 comparison in 2001.

Risk Factors, Neuroanatomical Correlates, and Outcome of Neuropsychiatric Symptoms in Alzheimer's Disease

BACKGROUND

An integrative model of neuropsychiatric symptoms (NPS) in Alzheimer's disease (AD) is lacking.

OBJECTIVE

In this study, we investigated the risk factors, anatomy, biology, and outcomes of NPS in AD.

METHODS

181 subjects were included from the Alzheimer's Disease Neuroimaging Study (ADNI). NPS were assessed with the Neuropsychiatric Inventory Questionnaire at baseline and 6 months. NPI >3 was used as a threshold for NPS positivity. Three NPS courses were characterized: 1) minimal/absent (negative at 0 and 6 months, n = 77); 2) fluctuating (positive only at one time point, n = 53); 3) persistent (positive at both time points, n = 51). We examined the association between NPS course and family history of dementia, personal history of psychiatric disorders, cerebrospinal fluid biomarkers, atrophy patterns, as well as longitudinal cognitive and functional measures at 12 and 24 months (MMSE, CDR-SOB, FAQ).

RESULTS

AD subjects with absent, fluctuating, or persistent NPS had similar CSF amyloid-β and tau levels. AD subjects with minimal/absent NPS had less personal history of psychiatric disorders (35%) than those with fluctuating (57%; p = 0.015) or persistent NPS (47%, not significant). At 24 months, AD subjects with persistent NPS had worse cognitive (MMSE; p = 0.05) and functional (CDR-SOB; p = 0.016) outcomes. Dorsolateral prefrontal atrophy was seen in persistent NPS, but not in fluctuating NPS.

CONCLUSIONS

Our results suggest that individuals with personal history of psychiatric disorders might be more vulnerable to develop NPS throughout the course of AD. The worst cognitive and functional outcomes associated with NPS in AD underscores the importance of monitoring NPS early in the disease course.

Normative Data for the Montreal Cognitive Assessment in Middle-Aged and Elderly Quebec-French People

OBJECTIVE

Given that aging is associated with higher risk of cognitive decline and dementia, improving early detection of cognitive impairment has become a research and clinical priority. The Montreal Cognitive Assessment (MoCA) is a screening instrument used to assess different aspects of cognition. Despite its widespread use, norms adjusted to the sociodemographics of Quebec-French people are not yet available. Such norms are however important because performance on neuropsychological tests varies according to sociodemographic variables including age, sex, and education. As such, the present study aimed to establish normative data for the MoCA in middle-aged and elderly Quebec-French population.

METHOD

For that purpose, 1,019 community-dwelling older adults aged between 41 and 98 were recruited. Participants from 12 recruiting sites completed the MoCA. Regression-based normative data were produced and cross-validated with a validation sample (n = 200).

RESULTS

Regression analyses indicated that older age, lower education level, and male sex were associated with poorer MoCA scores. The best predictive model included age (p < .001), education (p < .001), sex (p < .001), and a quadratic term for education (education X education; p < .001). This model explained a significant amount of variance of the MoCA score (p < .001, R2 = 0.26). A regression equation to calculate Z scores is presented.

CONCLUSIONS

This study provides normative data for the MoCA test in the middle-aged and elderly French-Quebec people. These data will facilitate more accurate detection and follow-up of the risk of cognitive impairment in this population, taking into account culture, age, education, and sex.

Mapping the initial DNA breaks in apoptotic Jurkat cells using ligation-mediated PCR

Apoptotic DNA degradation could be initiated by the accumulation of single-strand (ss) breaks in vulnerable chromatin regions, such as base unpairing regions (BURs), which might be preferentially targeted for degradation by both proteases and nucleases. We tested this hypothesis in anti-Fas-treated apoptotic Jurkat cells. Several nuclear proteins known for their association with both MARs and the nuclear matrix, that is, PARP, NuMA, lamin B and SATB1, were degraded, but the morphological rearrangement of the BUR-binding SATB1 protein was one of the earliest detected changes. Subsequently, we have identified several genes containing sequences homologous to the 25 bp BUR element of the IgH gene, a known SATB1-binding site, and examined the integrity of genomic DNA in their vicinity. Multiple ss breaks were found in close proximity to these sites relative to adjacent regions of DNA. Consistent with our prediction, the results indicated that the initiation of DNA cleavage in anti-Fas-treated Jurkat cells occurred within the BUR sites, which likely became accessible to endonucleases due to the degradation of BUR-binding proteins.

4-Hydroxytamoxifen is an isoform-specific inhibitor of orphan estrogen-receptor-related (ERR) nuclear receptors beta and gamma

Selective estrogen receptor modulators (SERMs) are synthetic molecules that exhibit tissue-specific activities. 4-hydroxytamoxifen (OHT) is a first generation SERM that functions as an antagonist in breast cancer cells but displays estrogen-like activities in the uterus and bone. The estrogen-receptor-related receptors (ERR) alpha, beta and gamma are orphan members of the superfamily of nuclear receptors. While the ERRs do not respond to natural estrogens, these receptors recognize the estrogen response element and have been shown to activate and repress gene expression in the absence of exogenously added ligand. Here we show that OHT disrupts the interaction between the orphan estrogen-receptor-related (ERR) receptors beta and gamma and a coregulator protein and abolishes the constitutive transcriptional activity of these receptors in transient transfection assays. In contrast, OHT has no effect on coregulator/ERR alpha interaction or its transcriptional activity. These results demonstrate the existence of a novel nuclear receptor-based pharmacological pathway that may contribute to the tissue-specific activities of OHT.