Free and cued selective reminding test predicts progression to Alzheimer’s disease in people with mild cognitive impairment

Cognitive markers of resilience to dementia in mild Neurocognitive Impairment: a meta- analysis

BACKGROUND

Numerous risk factors for dementia have been identified, but the concern of how cognitive functions in the mild Neurocognitive Impairment (mild NCI) stage predict dementia occurrence and incidence is still a matter of debate. The present paper aims to fill this gap by conducting an updated meta-analysis of studies examining the probability over time of developing dementia in relation to measures of global cognitive functioning, long-term verbal memory, complex attention, visuoconstructional ability, and language in the mild NCI stage.

METHODS

We conducted a systematic literature search up to March 2024 in PubMed, PsycINFO (PROQUEST), and Scopus databases. We used random-effects models to pool the ratio measure (odds, hazard, or risk ratios) for the association between cognitive domains and the risk of developing dementia in people with mild NCI.

RESULTS

The systematic search in electronic databases identified 44 relevant studies. Results showed that better performance in long-term verbal memory, visuoconstructional, and language abilities in individuals with mild NCI were associated with a lower risk of progression to dementia.

DISCUSSION

These findings might suggest that interventions aimed at preserving or enhancing these cognitive domains could be beneficial in delaying or preventing dementia onset, offering a potential therapeutic target for clinicians working with at-risk populations.

Entorhinal tau impairs short-term memory binding in preclinical Alzheimer's disease

OBJECTIVE

The entorhinal cortex (EC) is the first cortical region affected by tau pathology in Alzheimer's disease (AD), but its functions remain unclear. The EC is thought to support memory binding, which can be tested using the Visual Short-Term Memory Binding Test (VSTMBT). We aimed to test whether VSTMBT performance can identify individuals with preclinical AD before noticeable episodic memory impairment and whether these performances are related to amyloid (Aβ) pathology and/or EC tau burden.

METHODS

Ninety-four participants underwent the VSTMBT (including a shape-only condition (SOC) and a shape-color binding condition (SCBC)), standard neuropsychological assessment including the Preclinical Alzheimer Cognitive Composite (PACC5), an Aβ status examination, a 3D-T1 MRI and a [18F]-MK-6240 tau-PET scan. Participants were classified as follows: 54 Aβ-negative cognitively normal (Aβ - CN), 22 Aβ-positive CN (Aβ + CN, preclinical AD), and 18 Aβ + individuals with Mild Cognitive Impairment (Aβ + MCI, prodromal AD).

RESULTS

Aβ + CN individuals performed worse than Aβ-CN participants in the SCBC while the SOC only distinguished Aβ - CN from MCI participants. The SCBC performance was predicted by tau burden in the EC after adjusting for Aβ, white matter hypointensities, inferior temporal cortex (ITC) tau burden, age, sex, and education. The SCBC was more sensitive than the PACC5 in identifying CN individuals with a positive tau-PET scan.

CONCLUSION

Impaired visual short-term memory binding performance was evident from the preclinical stage of sporadic AD and related to tau pathology in the EC, suggesting that SCBC performance could detect early tau pathology in the EC among CN individuals.

Picture free and cued selective reminding test (P-FCSRT): A normative study for Chilean middle-aged and older adults

BackgroundThe Picture Free and Cued Selective Reminding Test (P-FCSRT) has proven useful in assessing episodic memory while controlling for interference from attentional processes. In Chile, studies have supported its diagnostic utility in detecting dementia in older adults, however, it lacks both normative data that account for the influence of age and educational level from mid-adulthood onwards, and the quantification of intrusive errors which have significant clinical value.ObjectiveThe aim of this study is to determine normative scores and intrusive errors for the P-FCSRT, controlling for sociodemographic factors (age and educational level) in the Chilean population.MethodsA total sample of 185 healthy participants from the Aging Mets cohort were recruited from three regions in Chile (Antofagasta, Santiago, and Puerto Montt). The P-FCSRT was administered to all participants. A multivariate regression-based normative approach was used to generate normative data, considering the effects of age, years of schooling, and sex.ResultsSignificant effects of age and years of schooling were found on P-FCSRT free recall, total recall, delayed recall, intrusions, and sensitivity to cues. Age had a distinct effect on each P-FCSRT dimension, whereas years of schooling had a consistent effect across them. Sex did not influence any P-FCSRT dimension.ConclusionsThis study is the first to provide normative data for the Chilean version of the P-FCSRT and will be beneficial for clinical neuropsychologists in improving the procedures for a more accurate assessment of episodic memory and related impairments.

Olfactory Testing and Gray Matter Volume: A Combined Approach to Predict the Conversion to Alzheimer

Background/Objectives: Olfactory decline is common in normal aging and frequent in neurodegenerative diseases such as Alzheimer's disease (AD). Therefore, it has been suggested as a marker for the Mild Cognitive Impairment (MCI) progression to AD. Although suggested, the relationship between olfactory deficits and cerebral atrophy in MCI conversion to AD is still debated. This study aims at investigating the olfaction-related morphological and behavioural alterations in MCI in order to understand whether they can predict the progression to AD. Methods: Twenty-seven MCI patients and thirty-five healthy controls (HCs) took part in the study, with follow-up showing conversion to AD in thirteen patients (converter-MCI, cMCI). The Burgarth Sniffin' Sticks Tests (threshold-TT, discrimination-DT, identification-IT) assessed the olfactory capacities. The Voxel-Based Morphometry (VBM) analysis investigated the atrophic patterns. Results: The Receiving Operating Characteristics analyses demonstrated that DT and IT could distinguish HC from MCI (DT Area Under Curve-AUC = 0.8; IT AUC = 0.8), as well as cMCI from sMCI (stable) patients (DT AUC = 0.7; IT AUC = 0.6), similarly to memory and executive functions tests. Olfactory performance positively correlated with memory tests in sMCI (all rhos ≥ 0.8, all ps < 0.01), whereas it positively correlated with executive functions in cMCI (all rhos ≥ 0.6, all ps < 0.05). VBM results revealed distinct atrophic patterns in cMCI, especially in the olfactory cortex, that were already present at the MCI diagnosis, before AD conversion. A larger volume of the olfactory cortex was associated with better memory and executive functions. Conclusions: Quantitative olfactory and morphological patterns represent non-invasive, predictive biomarkers of the MCI progression to AD; thus, their assessments at MCI onset allows earlier interventions for MCI patients.

Education bias in typical brief cognitive tests used for the detection of dementia in elderly population with low educational level: a critical review

Dementia is a significant decline in cognition that interfere with independent, daily functioning. Dementia is a syndrome caused by a myriad and include primary neurologic, neuropsychiatric, and medical conditions. It has been projected that the prevalence of dementia will triple in the elderly population by the year 2050. Despite the benefits of early diagnosis, there is an effective under-detection of around 62% of people with mild cognitive impairment (MCI) or dementia. One of the factors associated with this problem is that diagnostic techniques are affected by the educational level of those evaluated. This is an important aspect to consider in the use of brief cognitive tests for the detection of dementia. This review presents and critically analyzes the available evidence regarding the effect of educational level on the diagnostic utility of three of the most widely used tools in the clinical setting: the Mini-mental Test Examination (MMSE), the Montreal Cognitive Assessment (MoCA), and the Addenbrooke's Cognitive Examination (ACE). Previous evidence shows that the tasks that require reading, writing, calculation, phonological fluency, and visuoconstruction are affected by educational level. These results lead to discourage the use of these tests in older people with less than 6 years of schooling. The development of brief cognitive tests appropriate for people with a low educational level is recommended. We posit that adequate cognitive tests should not consider tasks or items that resemble characteristics of academic contexts and should be more analogous to daily activities situations.

[A comprehensive study of Alzheimer's disease biomarkers in plasma and cerebrospinal fluid]

OBJECTIVE

To determine, evaluate, and analyze the diagnostic value of various laboratory biomarkers of Alzheimer's disease (AD) in blood and cerebrospinal fluid (CSF).

MATERIAL AND METHODS

The concentrations of 93 potential biomarkers in plasma and CSF were studied in patients with AD at various stages (n=53) and independently in the group at the predementia stage (n=15).

RESULTS

Statistically significant correlations of various directions (p≤0.05) were found between the coefficients characterizing the amyloidosis and neurodegeneration (Aβ-42/Aβ-40, phTau181/Aβ-42, phTau181/oTau, oTau/Aβ-42) with markers associated with neuroinflammation, vascular disorders, angiogenesis, neuroimaging changes, and neuropsychological indicators. Previous studies of markers associated with inflammation in CSF in AD patients have shown mixed results, and no markers have been introduced into clinical practice so far. Many biomarkers associated with two classical pathogenetic links and other pathophysiological processes have been identified.

CONCLUSION

Coefficients reflecting two main pathogenetic processes in CSF of AD patients (Aβ-42/Aβ-40, phTau181/Aβ-42, phTau181/oTau, oTau/Aβ-42) are the most informative for verifying two main links in the disease pathogenesis-amyloidogenesis and neurodegeneration. In the group of patients with amnestic mild cognitive impairment (aMCI), statistically significant relationships of cytokines associated with neuroinflammation, growth factors, and complement system protein with coefficients of amyloidosis and neurodegeneration in CSF, as well as PET, MRI, and neuropsychological tests were shown; therefore, these indicators can also be considered as potential diagnostic biomarkers of early stages and possible predictors of MCI conversion to dementia. Such markers as GFAP, apolipoprotein A1, GDF-15, IFN-γ, IL-5, IL-7, IL-8, IL-10, IL-12p70, IL-13, IL-17, VEGF, and complement C3 should be considered as objects for further research as biomarkers for early diagnosis.

Therapeutic agents for Alzheimer's disease: a critical appraisal

Alzheimer's disease (AD) is the most common form of dementia. Mutations in genes and precursors of β amyloid (Aβ) are found in the familial form of the disease. This led to the evaluation of seven monoclonal antibodies against Aβ in subjects with AD, two of which were approved for use by the FDA. They caused only a small improvement in cognitive function, probably because they were given to those with much more prevalent sporadic forms of dementia. They also have potentially serious adverse effects. Oxidative stress and elevated pro-inflammatory cytokines are present in all subjects with AD and are well correlated with the degree of memory impairment. Drugs that affect these processes include TNFα blocking antibodies and MAPK p38 inhibitors that reduce cognitive impairment when given for other inflammatory conditions. However, their adverse effects and inability to penetrate the brain preclude their use for dementia. Rosiglitazone is used to treat diabetes, a risk factor for AD, but failed in a clinical trial because it was given to subjects that already had dementia. Ladostigil reduces oxidative stress and suppresses the release of pro-inflammatory cytokines from activated microglia without blocking their effects. Chronic oral administration to aging rats prevented the decline in memory and suppressed overexpression of genes adversely affecting synaptic function in relevant brain regions. In a phase 2 trial, ladostigil reduced the decline in short-term memory and in whole brain and hippocampal volumes in human subjects with mild cognitive impairment and had no more adverse effects than placebo.

Associating faces with names and meals as a biomarker of early AD in cognitively healthy individuals

The Learning and Associative Memory (LAM) test is a face-name associative memory test created to detect early Alzheimer's disease (AD). In a recent study, it was administered to cognitively healthy individuals with different levels of amyloid-β (Aβ) and tau burden. The key findings for LAM were: 1) selective correlations with Aβ levels, 2) unique discriminatory power between A + and A- individuals, 3) significantly higher areas under the curve in receiver operating curve analysis. Future research should focus on comparing performance on the LAM and face-name associative memory tests to determine the most effective method for detecting early signs of AD.

Forgetting rate for the familiarity and recollection components of recognition in amnestic mild cognitive impairment: A longitudinal study

Here we aimed to investigate the rate of forgetting of the familiarity and recollection components of recognition in patients at the onset of medial temporal lobe (MTL) pathology and destined to convert to Alzheimer's disease (AD). For this purpose, we conducted a longitudinal study of 13 patients who were diagnosed with amnestic mild cognitive impairment (a-MCI) at the first assessment and followed-up for 3 years. During this time, five patients converted to AD and eight remained in a stable condition of cognitive impairment. A group of 15 healthy subjects were enrolled as the control group (HC). In order to separately quantify the contribution of recollection and familiarity to recognition memory performance, the experimental sample was submitted to a modified version of Huppert and Piercy's procedure that included a Remember/Know paradigm. Data demonstrated that both stable and converter a-MCI patients forgot memory traces relative to the familiarity components of recognition at the same rate as HC. Conversely, converter a-MCI patients showed accelerated long-term forgetting specifically for the recollection component of recognition compared to stable a-MCI and HC. This is the first empirical demonstration that familiarity and recollection components of declarative memory are subject to different rates of forgetting in a-MCI patients as a function of their longitudinal clinical outcome. Our finding of accelerated long-term forgetting of the recollection component of recognition disclosed by converter a-MCI patients suggests that atrophy in the MTL not only interferes with the storage aspects but also disrupts the consolidation of memory traces.

Development of a prediction model of conversion to Alzheimer's disease in people with mild cognitive impairment: the statistical analysis plan of the INTERCEPTOR project

BACKGROUND

In recent years, significant efforts have been directed towards the research and development of disease-modifying therapies for dementia. These drugs focus on prodromal (mild cognitive impairment, MCI) and/or early stages of Alzheimer's disease (AD). Literature evidence indicates that a considerable proportion of individuals with MCI do not progress to dementia. Identifying individuals at higher risk of developing dementia is essential for appropriate management, including the prescription of new disease-modifying therapies expected to become available in clinical practice in the near future.

METHODS

The ongoing INTERCEPTOR study is a multicenter, longitudinal, interventional, non-therapeutic cohort study designed to enroll 500 individuals with MCI aged 50-85 years. The primary aim is to identify a biomarker or a set of biomarkers able to accurately predict the conversion from MCI to AD dementia within 3 years of follow-up. The biomarkers investigated in this study are neuropsychological tests (mini-mental state examination (MMSE) and delayed free recall), brain glucose metabolism ([18F]FDG-PET), MRI volumetry of the hippocampus, EEG brain connectivity, cerebrospinal fluid (CSF) markers (p-tau, t-tau, Aβ1-42, Aβ1-42/1-40 ratio, Aβ1-42/p-Tau ratio) and APOE genotype. The baseline visit includes a full cognitive and neuropsychological evaluation, as well as the collection of clinical and socio-demographic information. Prognostic models will be developed using Cox regression, incorporating individual characteristics and biomarkers through stepwise selection. Model performance will be evaluated in terms of discrimination and calibration and subjected to internal validation using the bootstrapping procedure. The final model will be visually represented as a nomogram.

DISCUSSION

This paper contains a detailed description of the statistical analysis plan to ensure the reproducibility and transparency of the analysis. The prognostic model developed in this study aims to identify the population with MCI at higher risk of developing AD dementia, potentially eligible for drug prescriptions. The nomogram could provide a valuable tool for clinicians for risk stratification and early treatment decisions.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03834402. Registered on February 8, 2019.

LAM Test: A New Cognitive Marker for Early Detection in Preclinical Alzheimer's Disease

Background

With the arrival of disease-modifying treatments, it is mandatory to find new cognitive markers that are sensitive to Alzheimer's disease (AD) pathology in preclinical stages.

Objective

To determine the utility of a newly developed Learning and Associative Memory face test: LAM test. This study examined the relationship between AD cerebrospinal fluid (CSF) biomarkers and performance on LAM test, and assessed its potential clinical applicability to detect subtle changes in cognitively healthy subjects at risk for AD.

Methods

We studied eighty cognitively healthy volunteers from the Valdecilla cohort. 61% were women and the mean age was 67.34 years (±6.416). All participants underwent a lumbar puncture for determination of CSF biomarkers and an extensive neuropsychological assessment, including performance on learning and associative memory indices of the LAM-test after 30 min and after 1 week, and two classic word lists to assess verbal episodic memory: the Rey Auditory Verbal Learning Test (RAVLT) and the Free and Cued Selective Reminding Test (FCSRT). We analyzed cognitive performance according to amyloid status (A+ versus A-) and to ATN model (A-T-N-; A+T-N-; A+T+N-/A+T+N+).

Results

Performance on the LAM-test was significantly correlated with CSF Aβ ratio. A+ participants performed worse on both learning (mean difference = 2.19, p = 0.002) and memory LAM measures than A- (mean difference = 2.19, p = 0.004). A decline in performance was observed along the Alzheimer's continuum, with significant differences between ATN groups.

Conclusions

Our findings suggest that LAM test could be a useful tool for the early detection of subjects within the AD continuum, outperforming classical memory tests.

Mild cognitive impairment identification based on motor and cognitive dual-task pooled indices

OBJECTIVE

This study investigates the possibility of adopting motor and cognitive dual-task (MCDT) approaches to identify subjects with mild cognitive impairment (MCI) and subjective cognitive impairment (SCI).

METHODS

The upper and lower motor performances of 44 older adults were assessed using the SensHand and SensFoot wearable system during three MCDTs: forefinger tapping (FTAP), toe-tapping heel pin (TTHP), and walking 10 m (GAIT). We developed five pooled indices (PIs) based on these MCDTs, and we included them, along with demographic data (age) and clinical scores (Frontal Assessment Battery (FAB) scores), in five logistic regression models.

RESULTS

Models which consider cognitively normal adult (CNA) vs MCI subjects have accuracies that range from 67% to 78%. The addition of clinical scores stabilised the accuracies, which ranged from 85% to 89%. For models which consider CNA vs SCI vs MCI subjects, there are great benefits to considering all three regressors (age, FAB score, and PIs); the overall accuracies of the three-class models range between 50% and 59% when just PIs and age are considered, whereas the overall accuracy increases by 18% when all three regressors are utilised.

CONCLUSION

Logistic regression models that consider MCDT PIs and age have been effective in distinguishing between CNA and MCI subjects. The inclusion of clinical scores increased the models' accuracy. Particularly high performances in distinguishing among CNA, SCI, and MCI subjects were obtained by the TTHP PI. This study suggests that a broader framework for MCDTs, which should encompass a greater selection of motor tasks, could provide clinicians with new appropriate tools.

Memory markers in the continuum of the Alzheimer's clinical syndrome

BACKGROUND

The individual and complementary value of the Visual Short-Term Memory Binding Test (VSTMBT) and the Free and Cued Selective Reminding Test (FCSRT) as markers to trace the AD continuum was investigated. It was hypothesised that the VSTMBT would be an early indicator while the FCSRT would inform on imminent progression.

METHODS

Healthy older adults (n=70) and patients with mild cognitive impairment (MCI) (n=80) were recruited and followed up between 2012 and 2017. Participants with at least two assessment points entered the study. Using baseline and follow-up assessments four groups were defined: Older adults who were healthy (HOA), with very mild cognitive but not functional impairment (eMCI), and with MCI who did and did not convert to dementia (MCI converters and non-converters).

RESULTS

Only the VSTMBT predicted group membership in the very early stages (HOA vs eMCI). As the disease progressed, the FCSRT became a strong predictor excluding the VSTMB from the models. Their complementary value was high during the mid-prodromal stages and decreased in stages closer to dementia.

DISCUSSION

The study supports the notion that neuropsychological assessment for AD needs to abandon the notion of one-size-fits-all. A memory toolkit for AD needs to consider tools that are early indicators and tools that suggest imminent progression. The VSTMBT and the FSCRT are such tools.

Harmonizing neuropsychological assessment for mild neurocognitive disorders in Europe

INTRODUCTION

Harmonized neuropsychological assessment for neurocognitive disorders, an international priority for valid and reliable diagnostic procedures, has been achieved only in specific countries or research contexts.

METHODS

To harmonize the assessment of mild cognitive impairment in Europe, a workshop (Geneva, May 2018) convened stakeholders, methodologists, academic, and non-academic clinicians and experts from European, US, and Australian harmonization initiatives.

RESULTS

With formal presentations and thematic working-groups we defined a standard battery consistent with the U.S. Uniform DataSet, version 3, and homogeneous methodology to obtain consistent normative data across tests and languages. Adaptations consist of including two tests specific to typical Alzheimer's disease and behavioral variant frontotemporal dementia. The methodology for harmonized normative data includes consensus definition of cognitively normal controls, classification of confounding factors (age, sex, and education), and calculation of minimum sample sizes.

DISCUSSION

This expert consensus allows harmonizing the diagnosis of neurocognitive disorders across European countries and possibly beyond.

A Lack of Practice Effects on Memory Tasks Predicts Conversion to Alzheimer Disease in Patients With Amnestic Mild Cognitive Impairment

The aim of the current study was to test the accuracy of practice effects, that is, improvement in test performance due to repeated neuropsychological evaluations, in identifying patients with amnestic mild cognitive impairment (a-MCI) at greater risk of conversion to Alzheimer disease (AD). For this purpose, we conducted a longitudinal study of 54 patients diagnosed with a-MCI at the first assessment and followed-up for 4 years. During this time, 18 patients converted to AD. Baseline and 6- to 12-month follow-up performances on a large set of neuropsychological tests were analyzed to determine their diagnostic ability to predict later conversion to dementia. Results demonstrate that a lack of practice effects on episodic memory tests is an accurate prognostic indicator of late conversion to AD in a-MCI patients. In fact, even though the performance of both groups was substantially comparable at the baseline evaluation, stable a-MCI patients greatly improved their memory performance at retest after 6 to 12 months; instead, scores of converter a-MCI remained stable or decreased passing from baseline to follow-up. Standardized z-change scores on memory tasks, which were computed as a reliable measure of performance change, classified group membership with very good overall accuracy, which was higher than the classification of converter and stable a-MCIs provided by baseline or follow-up scores. We hypothesize that the lack of practice effects on memory tasks mirrors the early involvement of medial temporal lobe areas in converter a-MCI that are fundamental for the consolidation of new memory traces.

Decreased Alpha Peak Frequency Is Linked to Episodic Memory Impairment in Pathological Aging

The Free and Cued Selective Reminding Test (FCSRT) is a largely validated neuropsychological test for the identification of amnestic syndrome from the early stage of Alzheimer's disease (AD). Previous electrophysiological data suggested a slowing down of the alpha rhythm in the AD-continuum as well as a key role of this rhythmic brain activity for episodic memory processes. This study therefore investigates the link between alpha brain activity and alterations in episodic memory as assessed by the FCSRT. For that purpose, 37 patients with altered FCSRT performance underwent a comprehensive neuropsychological assessment, supplemented by 18F-fluorodeoxyglucose positron emission tomography/structural magnetic resonance imaging (18FDG-PET/MR), and 10 min of resting-state magnetoencephalography (MEG). The individual alpha peak frequency (APF) in MEG resting-state data was positively correlated with patients' encoding efficiency as well as with the efficacy of semantic cues in facilitating patients' retrieval of previous stored word. The APF also correlated positively with patients' hippocampal volume and their regional glucose consumption in the posterior cingulate cortex. Overall, this study demonstrates that alterations in the ability to learn and store new information for a relatively short-term period are related to a slowing down of alpha rhythmic activity, possibly due to altered interactions in the extended mnemonic system. As such, a decreased APF may be considered as an electrophysiological correlate of short-term episodic memory dysfunction accompanying pathological aging.

The efficacy of the picture version of the free and cued selective reminding test to detect significant neurocognitive deficits in a Chilean population

The picture version of the Free and cued selective reminding test with immediate recall is a test adept at measuring the memory encoding and the effect of semantic cues. Furthermore, it is sensitive to detect early dementia stages. This study aimed to obtain psychometric properties of visual Buschke and Grober The Free and Cued Selective Reminding Test (FCSRT) in healthy older adults, mild neurocognitive disorders, and major neurocognitive subjects on a Chilean population.

METHOD

226 participants were included, 113 healthy older adults (HOA), 65 mild neurocognitive disorder (NCD) subjects, and 48 major NCD. Each individual was assessed with the same protocol.

RESULTS

The observed area under the curve (AUC) was higher than .90 in all the FCSRT measures in the major cognitive disorders and healthy older people.

CONCLUSION

according to the AUCs, it was shown that Free Recall, Sensitivity to Cueing Index, and Delay Recall of the FCSRT are suitable to detect major neurocognitive disorders.

Challenges to recruitment of participants with MCI in a multicentric neuropsychological study

BACKGROUND

Data on recruitment of Mild Cognitive Impairment (MCI) samples are seldom reported and this issue can be an important source of research waste.

AIM

To describe the recruitment challenges and reasons for non-eligibility faced during a bi-centre clinical study assessing the predictive value of a neuropsychological battery of the progression to dementia.

METHODS

Potential MCI participants were identified from databases of the two memory clinics based in Milan (Italy) and invited to the screening assessment.

RESULTS

About 50% of the cases initially identified were ineligible according to inclusion/exclusion criteria and the two sites took 22 months to recruit the planned 150 people. The main reasons for non-eligibility were the MMSE score (41%), age (14%), presence of cerebrovascular disorders (9%), perceptual deficits (6%), neurological (6%) or psychiatric (4%) comorbidities and low education (5%).

CONCLUSION

Awareness of the reasons for exclusion and of the time needed to recruit the planned sample would provide hints for the planning of future studies on MCI.

Deficits in short-term memory binding are detectable in individuals with brain amyloid deposition in the absence of overt neurodegeneration in the Alzheimer's disease continuum

The short-term memory binding (STMB) test involves the ability to hold in memory the integration between surface features, such as shapes and colours. The STMB test has been used to detect Alzheimer's disease (AD) at different stages, from preclinical to dementia, showing promising results. The objective of the present study was to verify whether the STMB test could differentiate patients with distinct biomarker profiles in the AD continuum. The sample comprised 18 cognitively unimpaired (CU) participants, 30 mild cognitive impairment (MCI) and 23 AD patients. All participants underwent positron emission tomography (PET) with Pittsburgh compound-B labelled with carbon-11 ([¹¹C]PIB) assessing amyloid beta (Aβ) aggregation (A) and 18fluorine-fluorodeoxyglucose ([¹⁸F]FDG)-PET assessing neurodegeneration (N) (A-N- [n = 35]); A+N- [n = 11]; A+ N+ [n = 19]). Participants who were negative and positive for amyloid deposition were compared in the absence (A-N- vs. A+N-) of neurodegeneration. When compared with the RAVLT and SKT memory tests, the STMB was the only cognitive task that differentiated these groups, predicting the group outcome in logistic regression analyses. The STMB test showed to be sensitive to the signs of AD pathology and may represent a cognitive marker within the AD continuum.

TMA-93 Validation by Alzheimer's Disease Biomarkers: A Comparison with the Free and Cued Selective Reminding Test on a Biobank Sample

BACKGROUND

The Memory Associative Test TMA-93 examines visual relational binding, characteristically affected in early-AD stages.

OBJECTIVE

We aim to validate the TMA-93 by biomarkers determination and compare its diagnostic characteristics with the Free and Cued Selective Reminding Test (FCSRT).

METHODS

Retrospective analysis of a Biobank database. Patients' records initially consulted for memory complaints, scored MMSE≥22, had TMA-93 and FCSRT tested, and AD biomarker determination (Amyloid-PET or CSF), either positive or negative, were selected. As cutoffs, we considered the 10-percentile for TMA-93 (P10/TMA-93), and "total free recall" (TFR) 21/22, total recall (TR) 43/44, and Cued Index < 0.77 for FCSRT from previous Spanish validation and normative studies. Diagnostic utilities were calculated using ROC curves and compared by the DeLong method. We studied if one test improved the other test's prediction, following a forward stepwise logistic regression model.

RESULTS

We selected 105 records: 64 "positive" and 41 "negative" biomarkers. TMA-93 total score diagnostic utility (AUC = 0.72; 95%CI:0.62-0.82) was higher than those of the FCSRT: TFR (AUC = 0.70; 95%CI: 0.60-0.80), TR (AUC = 0.63; 95%CI:0.53-0.74), and Cued Index (AUC = 0.62; 95%CI:0.52-0.73). The P10/TMA-93 cutoff showed 86%sensitivity, similar to that of the most sensitive FCSRT cutoff (TFR21/22, 89%) and 29%specificity, lower than that of the most specific FCSRT cutoff (Cued Index < 0.77, 57%). 32.8%of the positive-biomarker group scored above CI/0.77 but below p10TMA-93. The addition of TMA-93 total score to FCSRT variables improved significantly the biomarkers results' prediction.

CONCLUSION

TMA-93 demonstrated "reasonable" diagnostic utility, similar to FCSRT, for discriminating AD biomarker groups. TMA-93 total score improved the AD biomarker result prediction when added to FCSRT variables.

The Role of Free and Cued Selective Reminding Test in Predicting [18F]Florbetaben PET Results in Mild Cognitive Impairment and Mild Dementia

BACKGROUND

Free and Cued Selective Reminding Test (FCSRT) is a reliable cognitive marker for Alzheimer's disease (AD), and the identification of neuropsychological tests sensitive to the early signs of AD pathology is crucial both in research and clinical practice.

OBJECTIVE

The study aimed to ascertain the ability of FCSRT in predicting the amyloid load as determined from amyloid PET imaging (Amy-PET) in patients with cognitive disorders.

METHODS

For our purpose, 79 patients (71 MCI, 8 mild dementia) underwent a complete workup for dementia, including the FCSRT assessment and a [18F]florbetaben PET scan. FCSRT subitem scores were used as predictors in different binomial regression models.

RESULTS

Immediate free recall and delayed free recall were the best predictors overall in the whole sample; whereas in patients <76 years, all models further improved with immediate total recall (ITR) and Index of Sensitivity of Cueing (ISC) resulting the most accurate in anticipating Amy-PET results, with a likelihood of being Amy-PET positive greater than 85% for ITR and ISC scores of less than 25 and 0.5, respectively.

CONCLUSION

FCSRT proved itself to be a valid tool in dementia diagnosis, also being able to correlate with amyloid pathology. The possibility to predict Amy-PET results through a simple and reliable neuropsychological test might be helpful for clinicians in the dementia field, adding value to a paper and pencil tool compared to most costly biomarkers.

Innovative motor and cognitive dual-task approaches combining upper and lower limbs may improve dementia early detection

Motor and Cognitive Dual-Task (MCDT) represents an innovative chance to assess Mild Cognitive Impairment (MCI). We compare two novel MCDTs, fore-finger tapping (FTAP), toe-tapping (TTHP), to gold standards for cognitive screening (Mini-Mental State Examination-MMSE), and to a well-established MCDT (GAIT). We administered the aforementioned MCDTs to 44 subjects (MCIs and controls). Motor parameters were extracted, and correlations with MMSE investigated. Logistic regression models were built, and AUC areas computed. Spearman's correlation demonstrated that FTAP and TTHP significantly correlate with MMSE, at each cognitive load. AUC areas computed report similar (FTAP, 0.87), and even higher (TTHP, 0.97) capability to identify MCIs, if compared to GAIT (0.92). We investigated the use of novel MCDT approaches to assess MCI, aiming to enrich the clinical repertoire with objective and non-invasive tools. Our protocol shows good correlations with MMSE, and reaches high performances in identifying MCI, adopting simpler exercises.

Brain Resources: How Semantic Cueing Works in Mild Cognitive Impairment due to Alzheimer's Disease (MCI-AD)

Semantic cues in the Free and Cued Selective Reminding Test (FCRST) play a key role in the neuropsychological diagnosis of Amnesic Mild Cognitive Impairment due to Alzheimer’s Disease (MCI-AD); however, the neural bases of their impact of recall abilities are only partially understood. Here, we thus decided to investigate the relationships between brain metabolism and the FCSRT Index of Sensitivity of Cueing (ISC) in patients with MCI-AD and in healthy controls (HC). Materials: Thirty MCI-AD patients (age: 74.7 ± 5.7 years; education: 9.6 ± 4.6 years, MMSE score: 24.8 ± 3.3, 23 females) and seventeen HC (age: 66.5 ± 11.1 years; education: 11.53 ± 4.2 years, MMSE score: 28.4 ± 1.14, 10 females) who underwent neuropsychological evaluation and brain F-18 fluorodeoxyglucose Positron Emission Tomography (FDG-PET) were included in the study. Results: ISC was able to differentiate HC from MCI-AD subjects as shown by a ROC analysis (AUC of 0.978, effect size Hedges’s g = 2.89). MCI-AD subjects showed significant hypometabolism in posterior cortices, including bilateral inferior Parietal Lobule and Precuneus and Middle Temporal gyrus in the left hemisphere (VOI-1) compared to HC. ISC was positively correlated with brain metabolism in a single cluster (VOI-2) spanning the left prefrontal cortex (superior frontal gyrus) and anterior cingulate cortex (ACC) in the patient group (R² = 0.526, p < 0.001), but not in HC. Mean uptake values of VOI-2 did not differ between HC and MCI-AD. The structural connectivity analysis showed that VOI-2 is connected with the temporal pole, the cingulate gyrus and the posterior temporal cortices in the left hemisphere. Conclusion: In MCI-AD, the relative preservation of frontal cortex metabolic levels and their correlation with the ISC suggest that the left frontal cortices play a significant role in maintaining a relatively good memory performance despite the presence of posterior hypometabolism in MCI-AD.

The Italian INTERCEPTOR Project: From the Early Identification of Patients Eligible for Prescription of Antidementia Drugs to a Nationwide Organizational Model for Early Alzheimer's Disease Diagnosis

Alzheimer's disease is the most common age-related neurodegenerative disorder and its burden on patients, families, and society grows significantly with lifespan. Early modifications of risk-enhancing lifestyles and treatment initiation expand personal autonomy and reduce management costs. Many clinical trials with potentially disease-modifying drugs are devoted to mild cognitive impairment (MCI) prodromal-to-Alzheimer's disease. The identification of biomarkers for early diagnosis may thus be crucial for early intervention and identification of high-risk subjects, the most appropriate target of new drugs as soon as they will be discovered. INTERCEPTOR is a strategic project by the Italian Ministry of Health and the Italian Medicines Agency (AIFA), aiming to validate the best combination (highly accurate, non-invasive, available on the whole national territory and financially sustainable) of biomarkers and organizational model for early diagnosis. 500 MCI subjects will be enrolled at baseline and followed-up for 3 years for at least 400 of them in order to define a "hub & spoke" nationwide model with recruiting (spokes) centers for MCI identification and expert (hubs) centers for risk diagnosis.

The use of Motor and Cognitive Dual-Task quantitative assessment on subjects with mild cognitive impairment: A systematic review

Dementia and Alzheimer's Disease (AD) represent a health emergency. The identification of valid and noninvasive markers to identify people with Mild Cognitive Impairment (MCI) is profoundly advocated. This review outlines the use of quantitative Motor and Cognitive Dual-Task (MCDT) on MCI, by technologies aid. We describe the framework and the most valuable researches, displaying the adopted protocols, and the available technologies. PubMed Central, Web of Science, and Scopus were inspected between January 2010 and May 2020. 1939 articles were found in the initial quest. Exclusion criteria allowed the selection of the most relevant papers; 38 papers were included. The articles, regarding four technological solutions "wearable sensors", "personal devices", "optokinetic systems", and "electronic walkways", are organized into three categories: "Quantitative MCDT", "MCDT Inspired by Neuropsychological Test", and "MCDT for MCI Stimulation". MCDT might furnish clinical landmarks, supplying aid for disease stratication, risk prediction, and intervention optimization. Such protocols could foster the use of data mining and machine learning techniques. Notwithstanding, there is still a need to standardize and harmonize such protocols.

A ketogenic drink improves cognition in mild cognitive impairment: Results of a 6-month RCT

Introduction

Counteracting impaired brain glucose metabolism with ketones may improve cognition in mild cognitive impairment (MCI).

Methods

Cognition, plasma ketone response, and metabolic profile were assessed before and 6 months after supplementation with a ketogenic drink containing medium chain triglyceride (ketogenic medium chain triglyceride [kMCT]; 15 g twice/day; n = 39) or placebo (n = 44).

Results

Free and cued recall (Trial 1; P = .047), verbal fluency (categories; P = .024), Boston Naming Test (total correct answers; P = .033), and the Trail‐Making Test (total errors; P = .017) improved significantly in the kMCT group compared to placebo (analysis of covariance; pre‐intervention score, sex, age, education, and apolipoprotein E4 as covariates). Some cognitive outcomes also correlated positively with plasma ketones. Plasma metabolic profile and ketone response were unchanged.

Conclusions

This kMCT drink improved cognitive outcomes in MCI, at least in part by increasing blood ketone level. These data support further assessment of MCI progression to Alzheimer's disease.

How Dominant Hand and Foot Dexterity May Reveal Dementia Onset: A Motor and Cognitive Dual-Task Study

The combined provision of an arising number of dementia cases, and the substantial absence of effective treatments, led the scientific community toward the identification of early phases of this condition. Such an effort aims at the recognition of therapeutic windows and the characterization of the disease's different grades. In the last years, Motor and Cognitive Dual-Tasks (MCDT) have been widely used to address the early diagnosis of several neurocognitive disorders, among which dementia. Here we present different protocols: the walking MCDT, the toe-tapping MCDT, and the forefinger-tapping MCDT. Moreover, each task has been performed under different cognitive conditions: no cognitive effort, counting backwards by 1, 3, and 7. In this work, we report the results obtained through the combination of different motor and cognitive tasks, and we present 2 brand-new MCDT protocols, attempting to identify a sweet-spot for early diagnosis of dementia.

Elevated Plasma microRNA-206 Levels Predict Cognitive Decline and Progression to Dementia from Mild Cognitive Impairment

The need for practical biomarkers for early diagnosis of Alzheimer’s disease (AD) remains largely unmet. Here we investigated the use of blood-based microRNAs as prognostic biomarkers for AD and their application in a novel electrochemical microfluidic device for microRNA detection. MicroRNA transcriptome was profiled in plasma from patients with mild cognitive impairment (MCI) and AD. MicroRNAs Let-7b and microRNA-206 were validated at elevated levels in MCI and AD, respectively. MicroRNA-206 displayed a strong correlation with cognitive decline and memory deficits. Longitudinal follow-ups over five years identified microRNA-206 increases preceding the onset of dementia. MicroRNA-206 was increased in unprocessed plasma of AD and MCI subjects, detected by our microfluidic device. While increased Let-7b levels in plasma may be used to identify patients with MCI, changes in plasma levels of microRNA-206 may be used to predict cognitive decline and progression towards dementia at an MCI stage. MicroRNA quantification via a microfluidic device could provide a practical cost-effective tool for the stratification of patients with MCI according to risk of developing AD.

Lost or unavailable? Exploring mechanisms that affect retrograde memory in mild cognitive impairment and Alzheimer's disease patients

Retrograde amnesia has been largely documented in patients with amnestic mild cognitive impairment (a-MCI) and Alzheimer's disease (AD). However, it is still not clear whether ineffectiveness in recalling past acquired information reflects loss of individual memory traces or failure to access specific stored traces. We aimed to disentangle the differential contribution of storage and retrieval processes to the pattern of retrograde amnesia in these patients. This issue was investigated in 18 a-MCI and 19 AD patients who were compared to 20 healthy controls. A novel questionnaire about public events was used; it consisted of two procedures (i.e., a free recall test and a true/false recognition test). Crucial differences emerged in the way the two groups of patients performed the experimental tasks. In fact, although both a-MCI and AD patients showed a similar pattern of impairment on the free recall test, a-MCI patients were able to normalise their performance on the recognition test, thus overcoming their deficits at the time of recall. Conversely, AD patients showed both reduced free recall ability and diminished sensitivity to benefit from recognition in recalling public events. Our findings suggest that the memory processes underlying RA were different for a-MCI and AD. Deficits in remote memory are prevalently explained by impaired retrieval abilities in a-MCI and by impaired storage in AD. This distinction between retrograde amnesia due to defective trace utilisation in a-MCI and trace storage in AD is consistent with the temporal unfolding of declining anterograde memory over the course of disease progression to AD.

Measuring gait speed to better identify prodromal dementia

Slow gait speed has been shown to predict incident dementia and cognitive decline in older individuals. We aimed to summarize the evidence concerning the association of slow gait speed with cognitive decline and dementia, and discuss the possible shared pathways leading to cognitive and motor impairments, under the unifying hypothesis that body and mind are intimately connected. This is a scoping review supported by a systematic search of the literature, performed on PubMed and Web of Science. Longitudinal studies providing information on the role of gait speed in the prediction of cognitive decline and dementia in cognitively intact people and in those with initial cognitive impairment were eligible. Of 39 studies selected, including overall 57,456 participants, 33 reported a significant association between gait speed and cognitive outcomes, including dementia. Neurodegenerative pathology and cerebrovascular burden may damage cerebral areas involved in both cognitive functions and motor control. At the same time, systemic conditions, characterized by higher cardiorespiratory, and metabolic and inflammatory burden, can affect a number of organs and systems involved in motor functions, including the brain, having ultimately an impact on cognition. The interplay of body and mind seems relevant during the development of cognitive decline and dementia. The measurement of gait speed may improve the detection of prodromal dementia and cognitive impairment in individuals with and without initial cognitive deficits. The potential applicability of such a measure in both clinical and research settings points at the importance of expanding our knowledge about the common underlying mechanisms of cognitive and motor decline.