The free and cued selective reminding test for predicting progression to Alzheimer's disease in patients with mild cognitive impairment: A prospective longitudinal study

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.

Comparison of the Diagnostic Accuracy of Five Cognitive Screening Tests for Diagnosing Mild Cognitive Impairment in Patients Consulting for Memory Loss

Objectives: We aimed to evaluate and compare the diagnostic capacity of five cognitive screening tests for the diagnosis of mild cognitive impairment (MCI) in patients consulting by memory loss. Methods: A cross-sectional study involving 140 participants with a mean age of 74.42 ± 7.60 years, 87 (62.14%) women. Patients were classified as MCI or cognitively unimpaired according to a comprehensive neuropsychological battery. The diagnostic properties of the following screening tests were compared: Mini-Mental State Examination (MMSE), Addenbrooke's Cognitive Examination III (ACE-III) and Mini-Addenbrooke (M-ACE), Memory Impairment Screen (MIS), Montreal Cognitive Assessment (MoCA), and Rowland Universal Dementia Assessment Scale (RUDAS). Results: The area under the curve (AUC) was 0.861 for the ACE-III, 0.867 for M-ACE, 0.791 for MoCA, 0.795 for MMSE, 0.731 for RUDAS, and 0.672 for MIS. For the memory components, the AUC was 0.869 for ACE-III, 0.717 for MMSE, 0.755 for MoCA, and 0.720 for RUDAS. Cronbach's alpha was 0.827 for ACE-III, 0.505 for MMSE, 0.896 for MoCA, and 0.721 for RUDAS. Correlations with Free and Cued Selective Reminding Test were moderate with M-ACE, ACE-III, and MoCA, and moderate for the other tests. The M-ACE showed the best balance between diagnostic capacity and time of administration. Conclusions: ACE-III and its brief version M-ACE showed better diagnostic properties for the diagnosis of MCI than the other screening tests. MoCA and MMSE showed adequate properties, while the diagnostic capacity of MIS and RUDAS was limited.

Associations Between Free and Cued Selective Reminding Test and Cerebrospinal Fluid Biomarkers in Amnestic Mild Cognitive Impairment

Background

The Free and Cued Selective Reminding Test (FCSRT), assessing verbal episodic memory with controlled learning and semantic cueing, has been recommended for detecting the genuine encoding and storage deficits characterizing AD-related memory disorders.

Objective

The present study aims at investigating the ability of FCSRT in predicting cerebrospinal fluid (CSF) evidence of amyloid-β positivity in subjects with amnestic mild cognitive impairment (aMCI) and exploring its associations with amyloidopathy, tauopathy and neurodegeneration biomarkers.

Methods

120 aMCI subjects underwent comprehensive neurological and neuropsychological examinations, including the FCSRT assessment, and CSF collection; CSF Aβ42/40 ratio, p-tau181, and total-tau quantification were conducted by an automated CLEIA method on Lumipulse G1200. Based on the Aβ42/40 ratio value, subjects were classified as either A+ or A-.

Results

All FCSRT subitem scores were significantly lower in A+ group and significantly predicted the amyloid-β status, with Immediate Total Recall (ITR) being the best predictor. No significant correlations were found between FCSRT and CSF biomarkers in the A- aMCI group, while in the A+ aMCI group, all FCSRT subitem scores were negatively correlated with CSF p-tau181 and total-tau, but not with the Aβ42/40 ratio.

Conclusions

FCSRT confirms its validity as a tool for the diagnosis of AD, being able to predict the presence of amyloid-β deposition with high specificity. The associations between FCSRT subitem scores and CSF p-tau-181 and total-tau levels in aMCI due to AD could further encourage the clinical use of this simple and cost-effective test in the evaluation of individuals with aMCI.

Prodromal Alzheimer's Disease: Global Cognition, Cue Efficiency, and Cerebrospinal Fluid Neurofilament Light Values Predict Short-Term Conversion to Dementia

Background

Predicting which patients with prodromal AD (pAD) will imminently convert to dementia may be paramount in a memory clinical setting, especially with potential disease-modifying therapies on the horizon.

Objective

To explore a practical tool for this prediction, combining cognitive tests and cerebrospinal fluid (CSF) biomarkers.

Methods

We designed a longitudinal prospective, observational, and multicenter study, enrolling patients with pAD. Inclusion criteria comprised memory complaints, Mini-Mental State Examination (MMSE) score of≥22, memory impairment as indicated by the Free and Cued Selective Reminding Test with Immediate Recall (FCSRT + IR) and/or TMA-93, Clinical Dementia Rating-Global Score (CDR-GS) of 0.5, and positive CSF Aβ42/Aβ40 ratio (<0.095, Euroimmun). The primary outcome was the conversion to dementia (CDR-GS≥1) within the first year of follow-up, referred to as "short-term conversion". A multiple regression logistic model was adopted to design the "Predict Short-Term Conversion" (PSTC) score.

Results

Between 2020 and 2022, 83 patients were recruited. The median age was 74, with 49.4% being women. Twenty-five (30.1%) patients were classified as short-term converters. The PSTC score incorporated baseline scores on MMSE ( ≤24 = 3, >24 = 0) and FCSRT + IR Total Recall ( ≤14 = 4, >14 = 0), and CSF neurofilament light chains (NfLs) concentrations (β=0.001299). The PSTC score demonstrated an area under the curve of 0.78 (95% CI: 0.67-0.90, p < 0.001), with a cutoff value of 5.14 presenting 76% sensitivity and 80% specificity.

Conclusions

The PSTC score, comprising two relatively brief cognitive test scores and NfLs CSF concentrations, could be useful for predicting short-term converters among patients diagnosed with pAD.

Association of Stages of Objective Memory Impairment With Incident Symptomatic Cognitive Impairment in Cognitively Normal Individuals

BACKGROUND AND OBJECTIVES

Increasing evidence indicates that a subset of cognitively normal individuals has subtle cognitive impairment at baseline. We sought to identify them using the Stages of Objective Memory Impairment (SOMI) system. Symptomatic cognitive impairment was operationalized by a Clinical Dementia Rating (CDR) ≥0.5. We hypothesized that incident impairment would be higher for participants with subtle retrieval impairment (SOMI-1), higher still for those with moderate retrieval impairment (SOMI-2), and highest for those with storage impairment (SOMI-3/4) after adjusting for demographics and APOE ε4 status. A secondary objective was to determine whether including biomarkers of β-amyloid, tau pathology, and neurodegeneration in the models affect prediction. We hypothesized that even after adjusting for in vivo biomarkers, SOMI would remain a significant predictor of time to incident symptomatic cognitive impairment.

METHODS

Among 969 cognitively normal participants, defined by a CDR = 0, from the Knight Alzheimer Disease Research Center, SOMI stage was determined from their baseline Free and Cued Selective Reminding Test scores, 555 had CSF and structural MRI measures and comprised the biomarker subgroup, and 144 of them were amyloid positive. Cox proportional hazards models tested associations of SOMI stages at baseline and biomarkers with time to incident cognitive impairment defined as the transition to CDR ≥0.5.

RESULTS

Among all participants, the mean age was 69.35 years, 59.6% were female, and mean follow-up was 6.36 years. Participants in SOMI-1-4 had elevated hazard ratios for the transition from normal to impaired cognition in comparison with those who were SOMI-0 (no memory impairment). Individuals in SOMI-1 (mildly impaired retrieval) and SOMI-2 (moderately impaired retrieval) were at nearly double the risk of clinical progression compared with persons with no memory problems. When memory storage impairment emerges (SOMI-3/4), the hazard ratio for clinical progression increased approximately 3 times. SOMI stage remained an independent predictor of incident cognitive impairment after adjusting for all biomarkers.

DISCUSSION

SOMI predicts the transition from normal cognition to incident symptomatic cognitive impairment (CDR ≥0.5). The results support the use of SOMI to identify those cognitively normal participants most likely to develop incident cognitive impairment who can then be referred for biomarker screening.

Associations of Stages of Objective Memory Impairment With Amyloid PET and Structural MRI: The A4 Study

BACKGROUND AND OBJECTIVES

The goal of this work was to investigate the neuroimaging correlates of the Stages of Objective Memory Impairment (SOMI) system operationalized with the Free and Cued Selective Reminding Test (FCSRT), a widely used episodic memory measure.

METHODS

The FCSRT begins with a study phase in which items (e.g., grapes) are identified in response to unique semantic cues (e.g., fruit) that are used in the test phase to prompt recall of items not retrieved by free recall. There are 3 test trials of the 16 items (maximum 48). Data from 4,484 cognitively unimpaired participants from the Anti-Amyloid Treatment in Asymptomatic Alzheimer's (A4) study were used. All participants had amyloid PET imaging, and a subset of 1,262 β-amyloid (Aβ)-positive had structural MRIs. We compared the Aβ mean cortical standardized uptake value ratio (SUVR) and volumetric measures of hippocampus, parahippocampal gyrus, entorhinal cortex, and inferior temporal cortex between the 5 SOMI stages.

RESULTS

Participants had a mean age of 71.3 (SD 4.6) years; 40.6% were male; and 34.6% were APOE ε4 positive. Half had no memory impairment; the other half had retrieval deficits, storage limitations, or both. Analysis of covariance in the entire sample while controlling for age, sex, education, and APOE ε4 showed that individuals in higher SOMI stages had higher global amyloid SUVR (p < 0.001). Both SOMI-4 and -3 subgroups had higher amyloid SUVR than SOMI-0 and SOMI-1 subgroups. Individuals in higher SOMI stages had smaller hippocampal volume (p = 0.003), entorhinal cortex (p < 0.05), and inferior temporal lobes (p < 0.05), but there was no difference between parahippocampal gyrus volume of different SOMI stages. Pairwise comparison of SOMI subgroups showed that the SOMI-4, -3, and -2 subgroups had smaller hippocampal volume than the SOMI-0 and -1 subgroup. The SOMI-4 subgroup had significantly smaller entorhinal cortex and smaller inferior temporal lobe compared to all other groups.

DISCUSSION

Presence of Alzheimer disease pathology is closely related to memory impairment according to SOMI stages in the cognitively unimpaired sample of A4. Results from structural MRIs suggest that memory storage impairment (SOMI-3 and -4) is present when there is widespread medial temporal lobe atrophy.

TRIAL REGISTRATION INFORMATION

ClinicalTrials.gov identifier: NCT02008357.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that, in normal older individuals, higher stages of memory impairment assessed with FCSRT were associated with higher amyloid imaging burden and lower volume of hippocampus, entorhinal cortex, and inferior temporal lobes.

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.

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.

Predicting progression to Alzheimer's disease in subjects with amnestic mild cognitive impairment using performance on recall and recognition tests

The research of reliable procedures for predicting cognitive decline or stability in persons with amnestic mild cognitive impairment (a-MCI) is a major goal for the early identification of subjects in the prodromal stages of dementia. The aim of this study was to evaluate whether different memory performances on two procedures commonly used for the neuropsychological assessment of episodic memory (i.e., free recall and recognition) might be a key in predicting a-MCI patients' subsequent progression to Alzheimer's disease (AD). For this purpose, 80 patients diagnosed with a-MCI at the first assessment and followed-up for at least 3 years were included. During this time, 41 subjects remained in a stable condition of cognitive impairment or improved (stable-MCI) and 39 patients converted to AD dementia (converter-MCI). Sixty-two age- and education-matched healthy individuals were also recruited as healthy controls (HC). Baseline memory performance on the free recall (5th immediate and 15-min delayed) and yes/no recognition (the sensitivity measure d') of a 15-word list were analyzed. Results showed that stable-MCIs forgot significantly more information from immediate to delayed recall of the word list than HC, but exhibited a pronounced improvement of memory performance in the recognition test format. On the contrary, converter-MCIs showed diminished sensitivity in benefiting from cues for recognizing studied words. Word list recognition correctly classified group membership with good overall accuracy, which was higher compared to the classification of converter and stable a-MCIs provided by free recall; therefore, it could be a useful diagnostic tool for predicting progression to AD dementia from the prodromal stage.

Predictive Modeling of the Progression of Alzheimer's Disease with Recurrent Neural Networks

The number of service visits of Alzheimer's disease (AD) patients is different from each other and their visit time intervals are non-uniform. Although the literature has revealed many approaches in disease progression modeling, they fail to leverage these time-relevant part of patients' medical records in predicting disease's future status. This paper investigates how to predict the AD progression for a patient's next medical visit through leveraging heterogeneous medical data. Data provided by the National Alzheimer's Coordinating Center includes 5432 patients with probable AD from August 31, 2005 to May 25, 2017. Long short-term memory recurrent neural networks (RNN) are adopted. The approach relies on an enhanced "many-to-one" RNN architecture to support the shift of time steps. Hence, the approach can deal with patients' various numbers of visits and uneven time intervals. The results show that the proposed approach can be utilized to predict patients' AD progressions on their next visits with over 99% accuracy, significantly outperforming classic baseline methods. This study confirms that RNN can effectively solve the AD progression prediction problem by fully leveraging the inherent temporal and medical patterns derived from patients' historical visits. More promisingly, the approach can be customarily applied to other chronic disease progression problems.

Neural correlates of episodic memory in the Memento cohort

Introduction

The free and cued selective reminding test is used to identify memory deficits in mild cognitive impairment and demented patients. It allows assessing three processes: encoding, storage, and recollection of verbal episodic memory.

Methods

We investigated the neural correlates of these three memory processes in a large cohort study. The Memento cohort enrolled 2323 outpatients presenting either with subjective cognitive decline or mild cognitive impairment who underwent cognitive, structural MRI and, for a subset, fluorodeoxyglucose–positron emission tomography evaluations.

Results

Encoding was associated with a network including parietal and temporal cortices; storage was mainly associated with entorhinal and parahippocampal regions, bilaterally; retrieval was associated with a widespread network encompassing frontal regions.

Discussion

The neural correlates of episodic memory processes can be assessed in large and standardized cohorts of patients at risk for Alzheimer's disease. Their relation to pathophysiological markers of Alzheimer's disease remains to be studied.

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This is the largest cohort ever to be used in the study of the morpho-metabolic correlates of episodic memory in human, ensuring the validity of the obtained results.

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We found that encoding of information is linked to a posterior network previously evidenced to support working memory.

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The storage process was mainly supported in our study by medial temporal regions.

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Spontaneous retrieval of stimuli implicated broad neural networks including the frontal regions.

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These associations were particularly strong in APOE ε4 carriers suggesting that the free and selective reminding test is useful to detect Alzheimer's disease at an early stage.

Predicting dementia using socio-demographic characteristics and the Free and Cued Selective Reminding Test in the general population

BACKGROUND

Our study aimed to determine whether the consideration of socio-demographic features improves the prediction of Alzheimer's dementia (AD) at 5 years when using the Free and Cued Selective Reminding Test (FCSRT) in the general older population.

METHODS

Our analyses focused on 2558 subjects from the prospective Three-City Study, a cohort of community-dwelling individuals aged 65 years and over, with FCSRT scores. Four "residual scores" and "risk scores" were built that included the FCSRT scores and socio-demographic variables. The predictive performance of crude, residual and risk scores was analyzed by comparing the areas under the ROC curve (AUC).

RESULTS

In total, 1750 subjects were seen 5 years after completing the FCSRT. AD was diagnosed in 116 of them. Compared with the crude free-recall score, the predictive performances of the residual score and of the risk score were not significantly improved (AUC: 0.83 vs 0.82 and 0.88 vs 0.89 respectively).

CONCLUSION

Using socio-demographic features in addition to the FCSRT does not improve its predictive performance for dementia or AD.

Cognitive Decline and Reorganization of Functional Connectivity in Healthy Aging: The Pivotal Role of the Salience Network in the Prediction of Age and Cognitive Performances

Normal aging is related to a decline in specific cognitive processes, in particular in executive functions and memory. In recent years a growing number of studies have focused on changes in brain functional connectivity related to cognitive aging. A common finding is the decreased connectivity within multiple resting state networks, including the default mode network (DMN) and the salience network. In this study, we measured resting state activity using fMRI and explored whether cognitive decline is related to altered functional connectivity. To this end we used a machine learning approach to classify young and old participants from functional connectivity data. The originality of the approach consists in the prediction of the performance and age of the subjects based on functional connectivity by using a machine learning approach. Our findings showed that the connectivity profile between specific networks predicts both the age of the subjects and their cognitive abilities. In particular, we report that the connectivity profiles between the salience and visual networks, and the salience and the anterior part of the DMN, were the features that best predicted the age. Moreover, independently of the age of the subject, connectivity between the salience network and various specific networks (i.e., visual, frontal) predicted episodic memory skills either based on a standard assessment or on an autobiographical memory task, and short-term memory binding. Finally, the connectivity between the salience and the frontal networks predicted inhibition and updating performance, but this link was no longer significant after removing the effect of age. Our findings confirm the crucial role of episodic memory and executive functions in cognitive aging and suggest a pivotal role of the salience network in neural reorganization in aging.

Exploring anterograde memory: a volumetric MRI study in patients with mild cognitive impairment

BACKGROUND

The aim of this volumetric study was to explore the neuroanatomical correlates of the Free and Cued Selective Reminding Test (FCSRT) and the Delayed Matching-to-Sample-48 items (DMS-48), two tests widely used in France to assess verbal and visual anterograde memory. We wanted to determine to what extent the two tests rely on the medial temporal lobe, and could therefore be predictive of Alzheimer's disease, in which pathological changes typically start in this region.

METHODS

We analysed data from a cohort of 138 patients with mild cognitive impairment participating in a longitudinal multicentre clinical research study. Verbal memory was assessed using the FCSRT and visual recognition memory was evaluated using the DMS-48. Performances on these two tests were correlated to local grey matter atrophy via structural MRI using voxel-based morphometry.

RESULTS

Our results confirm the existence of a positive correlation between the volume of the medial temporal lobe and the performance on the FCSRT, prominently on the left, and the performance on the DMS-48, on the right, for the whole group of patients (family-wise error, P < 0.05). Interestingly, this region remained implicated only in the subgroup of patients who had deficient scores on the cued recall of the FCSRT, whereas the free recall was associated with prefrontal aspects. For the DMS-48, it was only implicated for the group of patients whose performances declined between the immediate and delayed trial. Conversely, temporo-parietal cortices were implicated when no decline was observed. Within the medial temporal lobe, the parahippocampal gyrus was prominently involved for the FCSRT and the immediate trial of the DMS-48, whereas the hippocampus was solely involved for the delayed trial of the DMS-48.

CONCLUSIONS

The two tests are able to detect an amnestic profile of the medial temporal type, under the condition that the scores remain deficient after the cued recall of the FCSRT or decline on the delayed recognition trial of the DMS-48. Strategic retrieval as well as perceptual/attentional processes, supported by prefrontal and temporo-parietal cortices, were also found to have an impact on the performances. Finally, the implication of the hippocampus appears time dependent, triggered by a longer delay than the parahippocampus, rather than determined by the sense of recollection or the encoding strength associated with the memory trace.