Preclinical prediction of AD using neuropsychological tests

NeuroBel: Spanish screening test for oral psycholinguistics disabilities in elderly people with mild cognitive impairment and early-stage Alzheimer's disease

INTRODUCTION

The NeuroBel is a short test that allows for psycholinguistic assessment of basic processes of oral comprehension and language production deterioration in the elderly. The objective is to carry out a pilot study of the initial reference values and cut-off points of this battery using a sample of Spanish elderly adults, with and without cognitive impairment, and detecting performance differences among them.

METHOD

NeuroBel consists of 8 tasks that analyze oral language functioning from the theoretical model proposed by the Psycholinguistic approach. Seventy-five Spanish monolingual adult-elderly participants of both genders. Of those, 25 with Alzheimer's disease (AD) in the initial phase, 25 with mild cognitive impairment (MCI) and 25 participants without cognitive impairment (Controls). All subjects were evaluated using NeuroBel.

RESULTS

There are significant differences between the three groups. The participants with AD are significantly worse in the total score of NeuroBel. A discriminant analysis shows that 86.7% of the cases appear correctly classified in the groups originally selected. Likewise, participants with MCI obtained results that are statistically significantly worse than the control group. NeuroBel shows a high correlation with the MMSE (.89) and Sensitivity (.96) in the determination of AD and cognitive deterioration (AD + MCI vs. Controls). The area under the ROC curve is .97 in the contrast of AD vs. Controls and .98 in the determination of cognitive deterioration (AD + MCI vs. Controls). The canonical discriminant functions and the precision cut-offs from the ROC analyses are also shown in the results.

CONCLUSIONS

NeuroBel is shown as a "very good" test in the detection of cognitive-linguistic impairment in elderly-adults.

Cognitive trajectories in relapsing-remitting multiple sclerosis: A longitudinal 6-year study

BACKGROUND

Information concerning longitudinal cognitive trajectories in multiple sclerosis (MS) is relatively scarce. Moreover, it is unclear which factors are associated with cognitive decline and what is the clinical impact of cognitive impairment (CI) in the long run.

OBJECTIVE

To investigate cognitive trajectories in relapsing-remitting multiple sclerosis (RRMS) patients, analyzing clinical and magnetic resonance imaging (MRI) predictors of cognitive decline.

METHODS

We enrolled 42 patients and 30 controls. They underwent brain MRI and clinical/neuropsychological evaluation at baseline and after 1, 2, and 6 years. We evaluated cognitive domains with principal component analysis and performed multivariable regression analyzing predictors of clinical/cognitive deterioration. We also performed repeated measures analysis to assess whether clinical progression was different according to CI at baseline.

RESULTS

A total of 23 (62.2%) patients deteriorated in combined cognitive domains after 6 years, most in processing speed and memory. The number of baseline impaired cognitive domains was strongly associated with 6-year cognitive (R² = 0.452; p < 0.001) and Expanded Disability Status Scale (EDSS) deterioration (R² = 0.263; p < 0.001). Patients with baseline CI in combined domains had worse clinical progression.

CONCLUSION

Isolated CI tends to become more widespread, affecting memory and processing speed alongside. The extent of baseline CI was the best predictor of both clinical and cognitive deterioration after 6 years.

The Executive Checklist (EC-10) - a new rating instrument for clinicians assessing dysexecutive behavior

Assessment of executive functions (EF) is often criticized for its lack of ecological validity. As a consequence, several self- and partner rating scales for EF have been developed, while rating scales designed for clinicians are lacking. We therefore developed the Executive Checklist (EC-10), a new rating scale for clinicians assessing dysexecutive behavior during neuropsychological assessment and examined its psychometric properties. Consecutive referrals from a memory clinic with subjective cognitive impairment (SCI; n = 27), mild cognitive impairment (MCI; n = 29), dementia (DEM; n = 16), as well as 11 healthy controls were assessed with the EC-10 while performing common neuropsychological tests. Results showed that the EC-10 had excellent inter-rater reliability, good internal consistency and modest relations to cognitive laboratory measures. The EC-10 increased the classification rate above and beyond the influence of neuropsychological tests when comparing patients with SCI and MCI or between cognitively impaired and non-impaired patients. Conclusively, the present study demonstrates that clinical observations can be quantified using the EC-10 and that this rating provides valuable information. As executive deficits are common in many neurological and neuropsychiatric disorders, validating the EC-10 in broader patient groups should be an important avenue for future research.

Rostral locus coeruleus integrity is associated with better memory performance in older adults

For decades, research into memory decline in human cognitive ageing has focused on neocortical regions, the hippocampus and dopaminergic neuromodulation. Recent findings indicate that the locus coeruleus (LC) and noradrenergic neuromodulation may also play an important role in shaping memory development in later life. However, technical challenges in quantification of LC integrity have hindered the study of LC-cognition associations in humans. Using high-resolution, neuromelanin-sensitive magnetic resonance imaging, we found that individual differences in learning and memory were positively associated with LC integrity across a variety of memory tasks in both younger (n = 66) and older adults (n = 228). Moreover, we observed functionally relevant age differences confined to rostral LC. Older adults with a more 'youth-like' rostral LC also showed higher memory performance. These findings link non-invasive, in vivo indices of LC integrity to memory in ageing and highlight the role of the LC norepinephrine system in the decline of cognition.

Distinct patterns of default mode and executive control network circuitry contribute to present and future executive function in older adults

Executive function (EF) performance in older adults has been linked with functional and structural profiles within the executive control network (ECN) and default mode network (DMN), white matter hyperintensities (WMH) burden and levels of Alzheimer's disease (AD) pathology. Here, we simultaneously explored the unique contributions of these factors to baseline and longitudinal EF performance in older adults. Thirty-two cognitively normal (CN) older adults underwent neuropsychological testing at baseline and annually for three years. Neuroimaging and AD pathology measures were collected at baseline. Separate linear regression models were used to determine which of these variables predicted composite EF scores at baseline and/or average annual change in composite ΔEF scores over the three-year follow-up period. Results demonstrated that low DMN deactivation, high ECN activation and WMH burden were the main predictors of EF scores at baseline. In contrast, poor DMN and ECN WM microstructure and higher AD pathology predicted greater annual decline in EF scores. Subsequent mediation analysis demonstrated that DMN WM microstructure uniquely mediated the relationship between AD pathology and ΔEF. These results suggest that functional activation patterns within the DMN and ECN and WMHs contribute to baseline EF while structural connectivity within these networks impact longitudinal EF performance in older adults.

Exercise and cognitive function in patients with end-stage kidney disease

In this review we summarize the research pertaining to the role of exercise in preventing cognitive decline in patients with end-stage kidney disease (ESKD). Impairment in cognitive function, especially in executive function, is common in patients with ESKD, and may worsen with maintenance dialysis as a result of retention of uremic toxins, recurrent cerebral ischemia, and high burden of inactivity. Cognitive impairment may lead to long-term adverse consequences, including dementia and death. Home-based and intradialytic exercise training (ET) are among the nonpharmacologic interventions identified to preserve cognitive function in ESKD. Additionally, cognitive training (CT) is an effective approach recently identified in this population. While short-term benefits of ET and CT on cognitive function were consistently observed in patients undergoing dialysis, more studies are needed to replicate these findings in diverse populations including kidney transplant recipients with long-term follow-up to better understand the health and quality of life consequences of these promising interventions. ET as well as CT are feasible interventions that may preserve or even improve cognitive function for patients with ESKD. Whether these interventions translate to improvements in quality of life and long-term health outcomes, including dementia prevention and better survival, are yet to be determined.

Screening for Cognitive Impairment in Geriatrics

There are many instruments for screening cognitive impairment. The common tools for screening cognitive impairment are categorized into 4 groups (very brief, brief, self-administered, and test batteries) in geriatrics. There are some tests used for specific tests of 6 cognitive domains (learning and memory, language, executive function, complex attention, and social cognition) by following the DSM-V criteria. Different settings, stages, conditions, and specific people need some specific tools for screening cognitive impairment. It must be noted that there is some harm in screening for cognitive impairment in geriatrics.

Single-photon emission computed tomography (SPECT) perfusion and neuropsychological performance in mild cognitive impairment

Single-photon emission computed tomography (SPECT) is an affordable neuroimaging technique that measures cerebral perfusion and has been utilized repeatedly in aging populations. However, we are aware of no studies to date examining relationships between SPECT imaging and comprehensive neuropsychological evaluations in a clinical sample of patients with mild cognitive impairment (MCI). Participants were 124 older adults with MCI (age, M = 75.07 years, SD = 7.65; years of education, M = 14.03, SD = 3.09; 60.2% female) who underwent neuropsychological evaluations and brain SPECT scans as part of their routine clinical care. Based on SPECT interpretations, participants were grouped by suspected etiology (i.e., the neuroradiologists noted that hypoperfusion patterns were most consistent with Alzheimer's disease, AD; frontotemporal lobar degeneration, FTLD; or other disease processes) and regional hypoperfusion (e.g., frontal, temporal, right/left hemisphere). Neuropsychological tests were grouped into domain scores (i.e., attention/processing speed, language, visuospatial, memory, executive; verbal/nonverbal). Consistent with a priori predictions, patients with an AD pattern of hypoperfusion scored lower than comparison groups on the attention/processing speed (partial χ² = 0.10) and memory (partial χ² = 0.07) composites. More patients with the AD-hypoperfusion signal met criteria for amnestic MCI (82%) than did those with a non-AD pattern (70%); this result approached statistical significance (p = .07). Contrary to hypotheses, patients whose SPECT scans were most consistent with FTLD did not underperform on the executive composite, and most regional analyses were nonsignificant. When integrating SPECT data into their clinical conceptualizations of MCI, neuropsychologists should place more weight on AD patterns of hypoperfusion, while de-emphasizing data suggestive of FTLD or regional pathology. Alternative neurodiagnostic markers may be more informative in these instances.

Motoric Cognitive Risk Syndrome: Prevalence and Risk of Cognitive Impairment in a Population Studied in the Mexican Health and Aging Study 2012-2015

OBJECTIVES

The aim of this study was to determine the prevalence of Motoric Cognitive Risk (MCR) syndrome, describe associated risk factors and to determine the risk of progression to cognitive impairment after three years of follow-up, in a sample of Mexican older adults.

DESIGN

A prospective panel study of health and aging in Mexico.

SETTING AND PARTICIPANTS

Baseline and follow-up information was obtained from the Mexican Health and Aging Study's 2012 and 2015 waves. A total of 726 subjects aged 60 years or older with normal cognition at baseline were classified into 4 groups: 1) with MCR, 2) with memory complaint only, 3) with slow gait speed only and, 4) without MCR. Cox regression analysis controlling for confounder factors was performed to determine the risk of progression to cognitive impairment in the MCR group.

MEASURES

Data such as gait speed, functional status and cognitive performance (standardized by age and sex in Mexican population) was collected.

RESULTS

MCR prevalence was 14.3%. When compared with non-MCR subjects, the presence of MCR was associated with older age (p<0.01), lower educational status (p=0.05), having two or more comorbidities (p<0.05) and diabetes mellitus diagnosis (p<0.05). At follow-up and after adjusting for confounders, MCR was associated with a 2.4-fold increased risk (95% CI: 1.28-4.26, p=.000) of cognitive impairment.

CONCLUSIONS

MCR syndrome increases the risk of cognitive impairment in Mexican older adults. Simple measurements such as gait evaluation in subjects with memory complaints could allow early identification of those at risk of developing cognitive impairment.

An investigation into the prevalence of cognitive impairment and the performance of older adults in Guilan province

Introduction: The escalating rate of old people with a functional impairment in Iran and the weakness of the family support due to the diminishing of family size have increased the demand for long-term care for the elderly with cognitive impairment (CI).

Objective: The purpose of this research is to explore the frequency of cognitive impairment in the elderly and its association with their daily functional impairment and disability.

Method: This is a cross-sectional and descriptive-analytic study conducted in 2016-2017. The study sample consisted of 393 elderly people who were 60 years old or older who live in of Guilan different counties. Samples were selected by using multi-stage cluster sampling. Subsequently, data were analyzed by using the Chi-square test and correlation and regression analysis conducted in SPSS 22.

Results: It was observed that 4.3, 28.6, and 37% of the subjects suffered from severe, moderate, and mild cognitive impairment, respectively. Cognitive impairment had a significant relationship with daily functioning and activities requiring special tools. Moreover, cognitive impairment in women, people with low education, and those over 70 years old was more common, and the difference between them was significant (p <0.001). Also, disability was significantly greater in the elderly with cognitive impairment.

Conclusion: Many old people need to be cared for after the appearance of cognitive impairment. Therefore, appropriate screening of cognitive impairments is conducive to early diagnosis and prevention of executive functioning problems.

The 12-Word Philadelphia Verbal Learning Test Performances in Older Adults: Brain MRI and Cerebrospinal Fluid Correlates and Regression-Based Normative Data

Background/Aims

This study evaluated neuroimaging and biological correlates, psychometric properties, and regression-based normative data of the 12-word Philadelphia Verbal Learning Test (PVLT), a list-learning test.

Methods

Vanderbilt Memory and Aging Project participants free of clinical dementia and stroke (n = 230, aged 73 ± 7 years) completed a neuropsychological protocol and brain MRI. A subset (n = 111) underwent lumbar puncture for analysis of Alzheimer's disease (AD) and axonal integrity cerebrospinal fluid (CSF) biomarkers. Regression models related PVLT indices to MRI and CSF biomarkers adjusting for age, sex, race/ethnicity, education, APOE-ε4 carrier status, cognitive status, and intracranial volume (MRI models). Secondary analyses were restricted to participants with normal cognition (NC; n = 127), from which regression-based normative data were generated.

Results

Lower PVLT performances were associated with smaller medial temporal lobe volumes (p < 0.05) and higher CSF tau concentrations (p < 0.04). Among NC, PVLT indices were associated with white matter hyperintensities on MRI and an axonal injury biomarker (CSF neurofilament light; p < 0.03).

Conclusion

The PVLT appears sensitive to markers of neurodegeneration, including temporal regions affected by AD. Conversely, in cognitively normal older adults, PVLT performance seems to relate to white matter disease and axonal injury, perhaps reflecting non-AD pathways to cognitive change. Enhanced normative data enrich the clinical utility of this tool.

Validity of a novel computerized screening test system for mild cognitive impairment

ABSTRACTBackground:The mobile screening test system for screening mild cognitive impairment (mSTS-MCI) was developed for clinical use. However, the clinical usefulness of mSTS-MCI to detect elderly with MCI from those who are cognitively healthy has yet to be validated. Moreover, the comparability between this system and traditional screening tests for MCI has not been evaluated.

OBJECTIVE

The purpose of this study was to examine the validity and reliability of the mSTS-MCI and confirm the cut-off scores to detect MCI.

METHOD

The data were collected from 107 healthy elderly people and 74 elderly people with MCI. Concurrent validity was examined using the Korean version of Montreal Cognitive Assessment (MoCA-K) as a gold standard test, and test-retest reliability was investigated using 30 of the study participants at four-week intervals. The sensitivity, specificity, positive predictive value, and negative predictive value (NPV) were confirmed through Receiver Operating Characteristic (ROC) analysis, and the cut-off scores for elderly people with MCI were identified.

RESULTS

Concurrent validity showed statistically significant correlations between the mSTS-MCI and MoCA-K and test-rests reliability indicated high correlation. As a result of screening predictability, the mSTS-MCI had a higher NPV than the MoCA-K.

CONCLUSIONS

The mSTS-MCI was identified as a system with a high degree of validity and reliability. In addition, the mSTS-MCI showed high screening predictability, indicating it can be used in the clinical field as a screening test system for mild cognitive impairment.

Dementia, Alzheimer's Disease, and Mortality after Hemodialysis Initiation

BACKGROUND AND OBJECTIVES

Older patients with ESKD experience rapid declines in executive function after initiating hemodialysis; these impairments might lead to high rates of dementia and Alzheimer's disease in this population. We estimated incidence, risk factors, and sequelae of diagnosis with dementia and Alzheimer's disease among older patients with ESKD initiating hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We studied 356,668 older (age ≥66 years old) patients on hemodialysis (January 1, 2001 to December 31, 2013) from national registry data (US Renal Data System) linked to Medicare. We estimated the risk (cumulative incidence) of diagnosis of dementia and Alzheimer's disease and studied factors associated with these disorders using competing risks models to account for death, change in dialysis modality, and kidney transplant. We estimated the risk of subsequent mortality using Cox proportional hazards models.

RESULTS

The 1- and 5-year risks of diagnosed dementia accounting for competing risks were 4.6% and 16% for women, respectively, and 3.7% and 13% for men, respectively. The corresponding Alzheimer's disease diagnosis risks were 0.6% and 2.6% for women, respectively, and 0.4% and 2.0% for men, respectively. The strongest independent risk factors for diagnosis of dementia and Alzheimer's disease were age ≥86 years old (dementia: hazard ratio, 2.11; 95% confidence interval, 2.04 to 2.18; Alzheimer's disease: hazard ratio, 2.11; 95% confidence interval, 1.97 to 2.25), black race (dementia: hazard ratio, 1.70; 95% confidence interval, 1.67 to 1.73; Alzheimer's disease: hazard ratio, 1.78; 95% confidence interval, 1.71 to 1.85), women (dementia: hazard ratio, 1.10; 95% confidence interval, 1.08 to 1.12; Alzheimer's disease: hazard ratio, 1.12; 95% confidence interval, 1.08 to 1.16), and institutionalization (dementia: hazard ratio, 1.36; 95% confidence interval, 1.33 to 1.39; Alzheimer's disease: hazard ratio, 1.10; 95% confidence interval, 1.05 to 1.15). Older patients on hemodialysis with a diagnosis of dementia were at 2.14-fold (95% confidence interval, 2.07 to 2.22) higher risk of subsequent mortality; those with a diagnosis of Alzheimer's disease were at 2.01-fold (95% confidence interval, 1.89 to 2.15) higher mortality risk.

CONCLUSIONS

Older patients on hemodialysis are at substantial risk of diagnosis with dementia and Alzheimer's disease, and carrying these diagnoses is associated with a twofold higher mortality.

Differences in road-crossing decisions between healthy older adults and patients with Alzheimer's disease

INTRODUCTION

This study investigated the differences in road-crossing behavior among healthy older adults and patients with Alzheimer's disease (AD).

METHOD

Twelve pedestrians with mild AD and 24 age-, gender-, and education-matched controls were examined with a battery of cognitive, visual, and motor tests. Using a simulated two-lane, one-way road-crossing situation, we determined the remaining time and safety margin for each participant in traffic situations involving different vehicle speeds (40 km/h vs. 60 km/h vs. 80 km/h), time gaps (5 s vs. 7 s vs. 9 s), and time of day (dusk vs. midday).

RESULTS

We found that patients with AD were more vulnerable to traffic crash while crossing the road than healthy older adults (Odds Ratio = 2.50, P < 0.05). Compared with healthy older adults, patients with AD were more severely affected by daylight conditions, faster vehicle speed, and shorter time gap. Participants in both groups had a significantly higher risk of unsafe crossing behavior if they had lower scores on the Mini-Mental State Examination (MMSE), Complex Figure Test - recall (CFT-Recall), Trail Making Test (TMT) B-A, Useful Field of View (UFOV) - total, and Visual Form Discrimination (VFD). We also found that when given a long enough time gap (9 s), patients with AD and healthy older adults used similar safe road-crossing behaviors, independent of other factors.

PRACTICAL APPLICATIONS

These results provide important suggestions for road design for patients with AD and healthy older adults during road-crossing.

Size matters: Grey matter brain reserve predicts executive functioning in the elderly

Preserved executive functioning (EF) is crucial for daily functioning in the elderly and it appears to predict dementia development. We sought to clarify the role of atrophy-corrected cortical grey matter (GM) volume as a potential brain reserve (BR) marker for EF in the elderly. In total, 206 pre-surgical subjects (72.50 ± 4.95 years; mean MMSE score 28.50) were investigated. EF was primarily assessed using the Trail Making Test B (TMT B). Global/ lobar GM volumes were acquired with T1 MP-RAGE. Adjusting for key covariates including a brain atrophy index (i.e. brain parenchymal fraction), multiple linear regression analysis was used to study associations of GM volumes and TMT B. All GM volumes - most notably of global GM - were significantly associated with TMT B independently of GM atrophy (ß = -0.201 to -0.275, p = 0.001-0.012). Using atrophy-corrected GM volume as an estimate of maximal GM size in youth may serve as a BR predictor for cognitive decline in future studies investigating BR in the elderly.

Neurocognitive functioning is associated with functional independence in newly diagnosed patients with temporal lobe glioma

BACKGROUND

Cancer and treatment-related neurocognitive dysfunction has the potential to significantly disrupt the lives of survivors. While neurocognitive functioning is known to predict aspects of patient-reported quality of life in individuals with glioma, little is known regarding the association between neurocognitive functioning and clinician-rated functional independence.

METHODS

Newly diagnosed patients with glioma in the left (n = 73; 49% glioblastoma) or right (n = 30; 57% glioblastoma) temporal lobe completed comprehensive neuropsychological testing. Clinicians rated patient functional independence using the Functional Independence Measure (FIM) and Karnofsky Performance Status (KPS) scale. Correlational and regression analyses were conducted to determine relationships between neurocognitive functioning and functional independence.

RESULTS

Tests of verbal learning, executive function, and language comprehension were moderately to strongly associated with clinician-rated functional independence, particularly for items pertaining to need for assistance with memory, problem-solving, and language functions. Stepwise linear regression showed that tests of verbal learning, executive functioning, and language comprehension predicted FIM ratings, together accounting for 40% of variance (P < .001). A test of executive functioning also predicted KPS scores and accounted for 19% of variance (P < .001).

CONCLUSIONS

In patients with newly diagnosed temporal lobe glioma, neurocognitive functioning is associated with functional independence. Verbal learning, executive functioning, and language comprehension demonstrated the strongest associations across both measures of functional independence. These findings provide support for the ecological validity of neuropsychological assessment by demonstrating the real-world clinical significance of objectively assessed neurocognitive functioning in glioma patients.

TOMMORROW neuropsychological battery: German language validation and normative study

Introduction

Assessment of preclinical Alzheimer's disease (AD) requires reliable and validated methods to detect subtle cognitive changes. The battery of standardized cognitive assessments that is used for diagnostic criteria for mild cognitive impairment due to AD in the TOMMORROW study have only been fully validated in English-speaking countries. We conducted a validation and normative study of the German language version of the TOMMORROW neuropsychological test battery, which tests episodic memory, language, visuospatial ability, executive function, and attention.

Methods

German-speaking cognitively healthy controls (NCs) and subjects with AD were recruited from a memory clinic at a Swiss medical center. Construct validity, test-retest, and alternate form reliability were assessed in NCs. Criterion and discriminant validities of the cognitive measures were tested using logistic regression and discriminant analysis. Cross-cultural equivalency of performance of the German language tests was compared with English language tests.

Results

A total of 198 NCs and 25 subjects with AD (aged 65-88 years) were analyzed. All German language tests discriminated NCs from persons with AD. Episodic memory tests had the highest potential to discriminate with almost twice the predictive power of any other domain. Test-retest reliability of the test battery was adequate, and alternate form reliability for episodic memory tests was supported. For most tests, age was a significant predictor of group effect sizes; therefore, normative data were stratified by age. Validity and reliability results were similar to those in the published US cognitive testing literature.

Discussion

This study establishes the reliability and validity of the German language TOMMORROW test battery, which performed similarly to the English language tests. Some variations in test performance underscore the importance of regional normative values. The German language battery and normative data will improve the precision of measuring cognition and diagnosing incident mild cognitive impairment due to AD in clinical settings in German-speaking countries.

Identification of Successful Cognitive Aging in the Alzheimer's Disease Neuroimaging Initiative Study

The present prospective observational study aimed to identify the existence of successful cognitive agers among a group of well-defined cognitively healthy older adults (n = 354, mean age = 75 years), and to examine baseline individual-level predictors and associated health outcomes over time. Episodic memory (EM) and executive function (EF) composite scores and multiple health outcomes were obtained annually over 5 years. Potential individual-level predictors that were related to Alzheimer's disease pathology or genetic risk, neurodegeneration, and vascular risks were collected at baseline. Three latent classes with matched age and education were identified using growth mixture modeling: a group of participants who exhibited high, stable EM and EF (40.7% of the sample, "successful agers"); a group who had initial high cognitive performance that declined over time (21.2%, "declining agers"); and a group who had normal (EM) or poor (EF) but stable cognitive performance over time (38.1%, "low stable agers"). The group classification predicted significant differences in the incidence of global cognitive impairment, the development of at least one depressive symptom, and everyday functional impairment. Sex, apolipoprotein E allele 4, amyloid-β1-42, and t-tau significantly contributed to the difference in cognitive trajectories between the successful agers and the other two groups. Characterizing successful cognitive agers who are relatively resistant to both tau and amyloid pathology provides potential pathways for promoting successful cognitive aging and preventing cognitive decline.

Faulty Adaptation to Repeated Face-Name Associative Pairs in Mild Cognitive Impairment is Predictive of Cognitive Decline

OBJECTIVE

We examined BOLD (Blood-Oxygen-Level Dependent) activity reduction upon stimuli repetition of face-name pairs in older adults with amnestic (aMCI) and non-amnestic (naMCI) mild cognitive impairment diagnosed using a comprehensive actuarial method, and relationships between activity reduction and behavioral indices.

METHOD

Twenty-nine cognitively healthy older adults (CHs) and 20 with MCI (n = 12 aMCI; n = 8 naMCI) underwent functional MRI event-related imaging, a comprehensive neuropsychological battery, and 1-year follow-up exam. During scanning, participants were shown face-name pairs 1-3 times and administered a post-scan recognition task.

RESULTS

The MCI group demonstrated less activity reduction upon repetition of face-name pairs within the MTL and other regions compared to CHs. Less activity reduction was associated with poorer Time 1 neuropsychological performance for the CH group and poorer post-scan recognition performance for the MCI group. Less activity reduction was related to poorer neuropsychological performance at Time 2 in the MCI group. Within MCIs, those with aMCI demonstrated less activity reduction upon repetition of face-name pairs than those with naMCI.

CONCLUSIONS

Distinct patterns of brain activity were identified in the MCI group compared to CHs, and aMCI compared to naMCI. Activated regions were not restricted to traditional memory circuitry, implicating a wider network of regions involved in the encoding of associative tasks. Findings add support to the hypothesis that lack of reduced BOLD activity reflects "faulty adaptation" to repeated stimuli and that reduction in activity represents successful encoding processes. They also provide further support for use of the face-name paradigm as a marker of prodromal Alzheimer's disease, and method to distinguish between MCI subtypes.

Longitudinal evaluation of Tau-P301L transgenic mice reveals no cognitive impairments at 17 months of age

Introduction

Tau is a microtubule-associated binding protein implicated in neurodegenerative tauopathies, including frontotemporal dementia (FTD) and Alzheimer's disease (AD). These diseases result in the intracellular accumulation of hyperphosphorylated tau in the form of neurofibrillary tangles, the presence of which is associated with cognitive deficits.

Methods

We conducted a longitudinal behavioral study to provide a profile of the TgTau(P301L)23027 transgenic mouse in multiple cognitive domains across multiple ages. P301L is the tau mutation most frequently observed in patients with frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17) and this mouse model recapitulates the progressive development of glial and neurofibrillary tangles, and associated cerebral atrophy observed in patients. We examined frontal cortex-dependent executive function and attention with the touchscreen 5-choice serial reaction time test (5-CSRTT) and assessed the function of temporal cortical structures using novel object recognition (OR).

Results

Despite using sensitive tasks, there were no apparent changes in executive function, attention, or recognition memory in the transgenic mice from 5 to 17 months of age.

Conclusions

This study represents the first comprehensive longitudinal analysis of cognition in the TgTauP301L mouse model and suggests that this model is not ideal for studying early attention and recognition memory impairments associated with tauopathy. However, spatial and object recognition memory impairments were observed during follow-up assessments when the mice were 18 and 21 months, respectively. These impairments are consistent with previous publications, and with a dementia-like phenotype in these mice when aged.

Neuropsychological Measures that Predict Progression from Mild Cognitive Impairment to Alzheimer's type dementia in Older Adults: a Systematic Review and Meta-Analysis

This study aimed to determine the extent to which cognitive measures can predict progression from mild cognitive impairment (MCI) to Alzheimer’s type dementia (AD), assess the predictive accuracy of different cognitive domain categories, and determine whether accuracy varies as a function of age and length of follow-up. We systematically reviewed and meta-analyzed data from longitudinal studies reporting sensitivity and specificity values for neuropsychological tests to identify individuals with MCI who will develop AD. We searched articles in Medline, Cochrane, EMBASE, PsycINFO, and the Web of Science. Methodological quality was assessed using the STARDem and QUADAS standards. Twenty-eight studies met the eligibility criteria (2365 participants) and reported predictive values from 61 neuropsychological tests with a 31-month mean follow-up. Values were pooled to provide combined accuracy for 14 cognitive domains. Many domains showed very good predictive accuracy with high sensitivity and specificity values (≥ 0.7). Verbal memory measures and many language tests yielded very high predictive accuracy. Other domains (e.g., executive functions, visual memory) showed better specificity than sensitivity. Predictive accuracy was highest when combining memory measures with a small set of other domains or when relying on broad cognitive batteries. Cognitive tests are excellent at predicting MCI individuals who will progress to dementia and should be a critical component of any toolkit intended to identify AD at the pre-dementia stage. Some tasks are remarkable as early indicators, whereas others might be used to suggest imminent progression.

Beta-amyloid and Cortical Thickness Reveal Racial Disparities in Preclinical Alzheimer's Disease

African Americans are two to four times more likely to develop dementia as Non-Hispanic Whites. This increased risk among African Americans represents a critical health disparity that affects nearly 43 million Americans. The present study tested the hypothesis that older African Americans with elevated beta-amyloid would show greater neurodegeneration (smaller hippocampal volumes and decreased cortical thickness) than older Non-Hispanic Whites with elevated beta-amyloid. Data from the Harvard Aging Brain Study (HABS) were used to form a group of older African Americans and two matched groups of Non-Hispanic White adults. Amyloid-positive African Americans had decreased cortical thickness in most of the Alzheimer's disease (AD) signature regions compared with amyloid-positive Non-Hispanic Whites. This factor was negatively correlated with age and white matter hypointensities. Using support vector regression, we also found some evidence that African Americans have an older "brain age" than Non-Hispanic Whites. These findings suggest that African Americans might be more susceptible to factors causing neurodegeneration, which then might accelerate the rate of a diagnosis of AD.

Longitudinal Assessment of Self- and Informant-Subjective Cognitive Complaints in a Sample of Healthy Late-Middle Aged Adults Enriched with a Family History of Alzheimer's Disease

OBJECTIVES

The purpose of this study was to investigate the longitudinal trajectory of self- and informant-subjective cognitive complaints (SCC), and to determine if SCC predict longitudinal changes in objective measures (OM) of cognitive function.

METHODS

The study included healthy and cognitively normal late middle-aged adults enriched with a family history of AD who were evaluated at up to three visits over a 4-year period. At each visit (Visit 1-3), self- and informant-SCC and OM were evaluated. Linear mixed models were used to determine if the longitudinal rate of change of self- and informant-SCC were associated with demographic variables, depressive symptoms, family history (FH), and apolipoprotein epsilon 4 (APOE4) status. The same modeling approach was used to examine the effect of Visit 1 SCC on longitudinal cognitive change after controlling for the same variables.

RESULTS

At Visit 1, more self-SCC were associated with fewer years of education and more depressive symptoms. SCC were also associated with poorer performance on cognitive measures, such that more self-SCC at Visit 1 were associated with poorer performance on memory and executive functioning measures at Visit 1, while more informant-SCC were associated with faster rate of longitudinal decline on a measure of episodic learning and memory. FH and APOE4 status were not associated with SCC.

DISCUSSION

Self- and informant-SCC showed an association with OM, albeit over different time frames in our late middle-aged sample. Additional longitudinal follow-up will likely assist in further clarifying these relationships as our sample ages and more pronounced cognitive changes eventually emerge. (JINS, 2017, 23, 617-626).

Problems in Classifying Mild Cognitive Impairment (MCI): One or Multiple Syndromes?

As the conceptual, methodological, and technological advances applied to dementias have evolved the construct of mild cognitive impairment (MCI), one problem encountered has been its classification into subtypes. Here, we aim to revise the concept of MCI and its subtypes, addressing the problems of classification not only from the psychometric point of view or by using alternative methods, such as latent class analysis, but also considering the absence of normative data. In addition to the well-known influence of certain factors on cognitive function, such as educational level and cultural traits, recent studies highlight the relevance of other factors that may significantly affect the genesis and evolution of MCI: subjective memory complaints, loneliness, social isolation, etc. The present work will contemplate the most relevant attempts to clarify the issue of MCI categorization and classification, combining our own data with that from recent studies which suggest the role of relevant psychosocial factors in MCI.

Anticholinergic Drug Use and Risk to Cognitive Performance in Older Adults with Questionable Cognitive Impairment: A Cross-Sectional Analysis

BACKGROUND

Age-associated decline in central cholinergic activity makes older adults susceptible to the harmful effects of anticholinergic (AC) medications; however, there is an inadequate understanding of the association and possible effects of AC drugs on cognition. This cross-sectional study examines the associations of AC medications on cognition among older adults with questionable cognitive impairment (QCI).

METHODS

For this cross-sectional study, we used a multicenter database of community-dwelling older adults (N = 7351) aged 60+ years with QCI, from September 2005 to March 2014, as the baseline data. The Anticholinergic Drug Scale was used to categorize AC drug load into no, low, or moderate/high groups. Individuals with a Clinical Dementia Rating-Sum of Boxes score between 0.5 and 2.5 were identified as having QCI, while cognitive performance was evaluated using the Neuropsychological Test Battery. The mean z-scores of neuropsychological tests were grouped into a global cognition score.

RESULTS

Participants who took AC medications were older, largely female, and had a higher prevalence of incontinence than those without AC exposure. Global cognition was significantly greater in the moderate/high-AC group than the no-AC group (-0.23 ± 0.53 vs. -0.32 ± 0.53). Multivariable linear regression showed that the global cognition score among the low- and moderate/high-AC groups, compared with the no-AC group, was 0.064 higher (p = 0.006 and p = 0.12, respectively).

CONCLUSIONS

This cross-sectional study indicates that older adults with QCI who were exposed to AC medications might have higher global cognitive scores than those without AC exposure. The observed associations indicate that older adults might experience some beneficial cognitive effects from AC drugs, possibly due to the therapeutic effects of these medications in controlling comorbidities, thus outweighing their adverse effects on cognition.

Group-Level Progressive Alterations in Brain Connectivity Patterns Revealed by Diffusion-Tensor Brain Networks across Severity Stages in Alzheimer's Disease

Alzheimer's disease (AD) is a chronically progressive neurodegenerative disease highly correlated to aging. Whether AD originates by targeting a localized brain area and propagates to the rest of the brain across disease-severity progression is a question with an unknown answer. Here, we aim to provide an answer to this question at the group-level by looking at differences in diffusion-tensor brain networks. In particular, making use of data from Alzheimer's Disease Neuroimaging Initiative (ADNI), four different groups were defined (all of them matched by age, sex and education level): G1 (N1 = 36, healthy control subjects, Control), G2 (N2 = 36, early mild cognitive impairment, EMCI), G3 (N3 = 36, late mild cognitive impairment, LMCI) and G4 (N4 = 36, AD). Diffusion-tensor brain networks were compared across three disease stages: stage I (Control vs. EMCI), stage II (Control vs. LMCI) and stage III (Control vs. AD). The group comparison was performed using the multivariate distance matrix regression analysis, a technique that was born in genomics and was recently proposed to handle brain functional networks, but here applied to diffusion-tensor data. The results were threefold: First, no significant differences were found in stage I. Second, significant differences were found in stage II in the connectivity pattern of a subnetwork strongly associated to memory function (including part of the hippocampus, amygdala, entorhinal cortex, fusiform gyrus, inferior and middle temporal gyrus, parahippocampal gyrus and temporal pole). Third, a widespread disconnection across the entire AD brain was found in stage III, affecting more strongly the same memory subnetwork appearing in stage II, plus the other new subnetworks, including the default mode network, medial visual network, frontoparietal regions and striatum. Our results are consistent with a scenario where progressive alterations of connectivity arise as the disease severity increases and provide the brain areas possibly involved in such a degenerative process. Further studies applying the same strategy to longitudinal data are needed to fully confirm this scenario.

Is "Learning" episodic memory? Distinct cognitive and neuroanatomic correlates of immediate recall during learning trials in neurologically normal aging and neurodegenerative cohorts

Although commonly interpreted as a marker of episodic memory during neuropsychological exams, relatively little is known regarding the neurobehavior of "total learning" immediate recall scores. Medial temporal lobes are clearly associated with delayed recall performances, yet immediate recall may necessitate networks beyond traditional episodic memory. We aimed to operationalize cognitive and neuroanatomic correlates of total immediate recall in several aging syndromes. Demographically-matched neurologically normal adults (n=91), individuals with Alzheimer's disease (n=566), logopenic variant primary progressive aphasia (PPA) (n=34), behavioral variant frontotemporal dementia (n=97), semantic variant PPA (n=71), or nonfluent/agrammatic variant PPA (n=39) completed a neurocognitive battery, including the CVLT-Short Form trials 1-4 Total Immediate Recall; a majority subset also completed a brain MRI. Regressions covaried for age and sex, and MMSE in cognitive and total intracranial volume in neuroanatomic models. Neurologically normal adults demonstrated a heterogeneous pattern of cognitive associations with total immediate recall (executive, speed, delayed recall), such that no singular cognitive or neuroanatomic correlate uniquely predicted performance. Within the clinical cohorts, there were syndrome-specific cognitive and neural associations with total immediate recall; e.g., semantic processing was the strongest cognitive correlate in svPPA (partial r=0.41), while frontal volumes was the only meaningful neural correlate in bvFTD (partial r=0.20). Medial temporal lobes were not independently associated with total immediate recall in any group (ps>0.05). Multiple neurobehavioral systems are associated with "total learning" immediate recall scores that importantly differ across distinct clinical syndromes. Conventional memory networks may not be sufficient or even importantly contribute to total immediate recall in many syndromes. Interpreting learning scores as equivalent to episodic memory may be erroneous.

Making sense of self in Alzheimer's disease: reflective function and memory

OBJECTIVE

The current investigation examined the relationship between cognitive impairment and sense of self in Alzheimer's disease (AD).

METHOD

Forty-nine participants with dementia associated with AD were recruited through memory clinics in Victoria, Australia. The 26 participants of the healthy control sample were recruited from a retirement village. Self was measured via the Reflective Self-Function Scale - a theory of mind indicator that provides personal and social self-reflection scores. Cognitive assessment included measures of new learning, executive function, and speed of information processing.

RESULTS

A reduction in sense of self in mild AD was demonstrated in both personal and social domains, as compared to healthy adults of a similar age. With a focus on specific cognitive impairment relationships, new learning was found to predict personal self-reflection, whereas speed of information processing predicted social self-reflection capacity.

CONCLUSION

Findings suggest that deficits in new learning ability contribute to a reduced ability of people with early AD to understand their mental world and interpret thoughts, feelings, and beliefs about themselves. This impaired capacity to self-reflect will be intrusive in daily activities that require monitoring of current self-performance. Furthermore, with reduced speed of information processing found to impact on ability to reflect on social relations, individuals with AD are placed at risk of reduced ability to understand their social world, including communicating and interacting with others. Notwithstanding the overall group findings, individual variability was evident which reinforces the need for person-centred care in dementia.

Association of long-term patterns of depressive symptoms and attention/executive function among older men with and without human immunodeficiency virus

Older HIV-infected men are at higher risk for both depression and cognitive impairments, compared to HIV-uninfected men. We evaluated the association between longitudinal patterns of depressive symptoms and attention/executive function in HIV-infected and HIV-uninfected men aged 50+ years to understand whether HIV infection influenced the long-term effect of depression on attention/executive function. Responses to the Center for Epidemiologic Studies-Depression scale and attention/executive function tests (Trail Making Test Part B and Symbol Digit Modalities Test) were collected semiannually from May 1986 to April 2015 in 1611 men. Group-based trajectory models, stratified by HIV status, were used to identify latent patterns of depressive symptoms and attention/executive function across 12 years of follow-up. We identified three depression patterns for HIV-infected and HIV-uninfected men (rare/never 50.0 vs. 60.6%, periodically depressed 29.6 vs. 24.5%, chronic high 20.5 vs.15.0%, respectively) and three patterns of attention/executive function for HIV-infected and HIV-uninfected men (worst-performing 47.4 vs. 45.1%; average 41.9 vs. 47.0%; best-performing 10.7 vs. 8.0%, respectively). Multivariable logistic regression models were used to assess associations between depression patterns and worst-performing attention/executive function. Among HIV-uninfected men, those in the periodically depressed and chronic high depressed groups had higher odds of membership in the worst-performing attention/executive function group (adjusted odds ratio [AOR] = 1.45, 95% CI 1.04, 2.03; AOR = 2.25, 95% CI 1.49, 3.39, respectively). Among HIV-infected men, patterns of depression symptoms were not associated with patterns of attention/executive function. Results suggest that HIV-uninfected, but not HIV-infected, men with chronic high depression are more likely to experience a long-term pattern of attention/executive dysfunction.

Individual Differences in Cognitive Function in Older Adults Predicted by Neuronal Selectivity at Corresponding Brain Regions

Relating individual differences in cognitive abilities to neural substrates in older adults is of significant scientific and clinical interest, but remains a major challenge. Previous functional magnetic resonance imaging (fMRI) studies of cognitive aging have mainly focused on the amplitude of fMRI response, which does not measure neuronal selectivity and has led to some conflicting findings. Here, using local regional heterogeneity analysis, or Hcorr , a novel fMRI analysis technique developed to probe the sparseness of neuronal activations as an indirect measure of neuronal selectivity, we found that individual differences in two different cognitive functions, episodic memory and letter verbal fluency, are selectively related to Hcorr -estimated neuronal selectivity at their corresponding brain regions (hippocampus and visual-word form area, respectively). This suggests a direct relationship between cognitive function and neuronal selectivity at the corresponding brain regions in healthy older adults, which in turn suggests that age-related neural dedifferentiation might contribute to rather than compensate for cognitive decline in healthy older adults. Additionally, the capability to estimate neuronal selectivity across brain regions with a single data set and link them to cognitive performance suggests that, compared to fMRI-adaptation-the established fMRI technique to assess neuronal selectivity, Hcorr might be a better alternative in studying normal aging and neurodegenerative diseases, both of which are associated with widespread changes across the brain.

Neuropsychological measures that detect early impairment and decline in preclinical Alzheimer disease

Identifying which neuropsychological measures detect early cognitive changes associated with Alzheimer disease (AD), brain pathology would be helpful clinically for the diagnosis of early AD and for the design of clinical trials. We evaluated which neuropsychological measures in our cognitive battery are most strongly associated with cerebrospinal fluid (CSF) biomarkers of AD brain pathology. We studied a large cohort (n = 233) of middle-to older-aged community-dwelling individuals (mean age 61 years) who had no clinical symptoms of dementia and underwent baseline CSF collection at baseline. Participants completed a battery of 9 neuropsychological measures at baseline and then every 1 to 3 years. CSF tau/Aβ42 was associated with baseline performance on 5/9 neuropsychological measures, especially measures of episodic memory, and longitudinal performance on 7/9 neuropsychological measures, especially measures of global cognition. The free recall portion of the Free and Cued Selective Reminding Task (FCSRT-free) detected declining cognition in the high CSF tau/Aβ42 group the earliest, followed by another measure of episodic memory and a sequencing task.

Implementation of subjective cognitive decline criteria in research studies

INTRODUCTION

Subjective cognitive decline (SCD) manifesting before clinical impairment could serve as a target population for early intervention trials in Alzheimer's disease (AD). A working group, the Subjective Cognitive Decline Initiative (SCD-I), published SCD research criteria in the context of preclinical AD. To successfully apply them, a number of issues regarding assessment and implementation of SCD needed to be addressed.

METHODS

Members of the SCD-I met to identify and agree on topics relevant to SCD criteria operationalization in research settings. Initial ideas and recommendations were discussed with other SCD-I working group members and modified accordingly.

RESULTS

Topics included SCD inclusion and exclusion criteria, together with the informant's role in defining SCD presence and the impact of demographic factors.

DISCUSSION

Recommendations for the operationalization of SCD in differing research settings, with the aim of harmonization of SCD measurement across studies are proposed, to enhance comparability and generalizability across studies.

Optimizing Neuropsychological Assessments for Cognitive, Behavioral, and Functional Impairment Classification: A Machine Learning Study

Subjects with Alzheimer's disease (AD) show loss of cognitive functions and change in behavioral and functional state affecting the quality of their daily life and that of their families and caregivers. A neuropsychological assessment plays a crucial role in detecting such changes from normal conditions. However, despite the existence of clinical measures that are used to classify and diagnose AD, a large amount of subjectivity continues to exist. Our aim was to assess the potential of machine learning in quantifying this process and optimizing or even reducing the amount of neuropsychological tests used to classify AD patients, also at an early stage of impairment. We investigated the role of twelve state-of-the-art neuropsychological tests in the automatic classification of subjects with none, mild, or severe impairment as measured by the clinical dementia rating (CDR). Data were obtained from the ADNI database. In the groups of measures used as features, we included measures of both cognitive domains and subdomains. Our findings show that some tests are more frequently best predictors for the automatic classification, namely, LM, ADAS-Cog, AVLT, and FAQ, with a major role of the ADAS-Cog measures of delayed and immediate memory and the FAQ measure of financial competency.

Association of Increased Serum ACE Activity with Logical Memory Ability in Type 2 Diabetic Patients with Mild Cognitive Impairment

Background: Angiotensin-converting enzyme (ACE) is involved in the chronic complications of type 2 diabetes mellitus (T2DM) and Alzheimer's disease. This study aimed to assess the pathogenetic roles of ACE and the genetic predisposition of its insertion/deletion (I/D) polymorphism in mild cognitive impairment (MCI) among T2DM patients.

Methods: A total of 210 T2DM patients were enrolled. Among these patients, 116 satisfied the MCI diagnostic criteria and 94 exhibited healthy cognition. The cognitive functions of the patients were extensively assessed. The serum level and activity of ACE were measured via enzyme-linked immunosorbent assay and ultraviolet spectrophotography. The single-nucleotide polymorphisms of I/D gene of ACE were analyzed.

Results: The serum level and activity of ACE in diabetic MCI patients (p = 0.022 and p = 0.008, respectively) were both significantly higher than those in the healthy controls. A significant negative correlation was found between their ACE activity and logical memory test score (LMT) (p = 0.002). Multiple stepwise regression iterated the negative correlation between ACE activity and LMT score (p = 0.035). Although no significant difference was found in the genotype or allele distribution of ACE I/D polymorphism between the groups, the serum levels and activity of ACE were higher in the DD group than in the ID and II groups (p < 0.05).

Conclusions: Serum ACE activity could better predict logical memory in T2DM patients than ACE level. Further investigations on a large population size are necessary to test whether the D-allele of the ACE gene polymorphism is susceptible to memory deterioration.

Alzheimer's disease: The influence of age on clinical heterogeneity through the human brain connectome

INTRODUCTION

One major factor that influences the heterogeneity of Alzheimer's disease (AD) is age: younger AD patients more frequently exhibit atypical forms of AD. We propose that this age-related heterogeneity can be understood better by considering age-related differences in atrophy in the context of large-scale brain networks subserving cognitive functions that contribute to memory.

METHODS

We examined data from 75 patients with mild AD dementia from Alzheimer's Disease Neuroimaging Initiative. These individuals were chosen because they have cerebrospinal fluid amyloid and p-tau levels in the range suggesting the presence of AD neuropathology, and because they were either younger than age 65 years early-onset AD (EOAD) or age 80 years or older late-onset AD (LOAD).

RESULTS

In the EOAD group, the most prominent atrophy was present in the posterior cingulate cortex, whereas in the LOAD group, atrophy was most prominent in the medial temporal lobe. Structural covariance analysis showed that the magnitude of atrophy in these epicenters is strongly correlated with a distributed atrophy pattern similar to distinct intrinsic connectivity networks in the healthy brain. An examination of memory performance in EOAD dementia versus LOAD dementia demonstrated relatively more prominent impairment in encoding in the EOAD group than in the LOAD group, with similar performance in memory storage in LOAD and EOAD but greater impairment in semantic memory in LOAD than in EOAD.

DISCUSSION

The observations provide novel insights about age as a major factor contributing to the heterogeneity in the topography of AD-related cortical atrophy.

The Differential Effects of Alzheimer's Disease and Lewy Body Pathology on Cognitive Performance: a Meta-analysis

Differential diagnosis of Alzheimer's disease (AD) from normal aging and other dementia etiologies is imperative for disease specific treatment options and long-term care planning. Neuropathological confirmation is the gold standard for neurodegenerative disease diagnosis, yet most published studies examining the use of neuropsychological tests in the differential diagnosis of dementia rely upon clinical diagnostic outcomes. The present study undertook a meta-analytic review of the literature to identify cognitive tests and domains that allow for the differentiation of individuals with AD pathology from individuals with dementia with Lewy Bodies (DLB) pathology and pathology-free individuals. A comprehensive literature search yielded 14 studies that met the inclusion criteria for the present meta-analysis. Six studies comprised 222 decedents with AD compared to 433 normal controls, and eight studies comprised 431 cases of AD compared to 155 decedents with DLB. Results revealed that the effect of having neuropathologically confirmed AD versus DLB lowered performance in the memory domain, and having DLB decreased performance in the visuospatial domain. No single test differed significantly across the AD and DLB groups. For the AD and pathology free comparison, results indicated that that AD was associated with poorer performance on the memory and language domains. With respect to specific cognitive tests, AD produced lower scores on list learning tests, category fluency, and the Digit Symbol substitution test. The limited number of studies meeting inclusion criteria warrants formulation of guidelines for reporting in clinico-pathological studies; suggested guidelines are provided.

A comparison of theoretical and statistically derived indices for predicting cognitive decline

INTRODUCTION

Both theoretical and statistically derived approaches have been used in research settings for predicting cognitive decline.

METHODS

Fifty-eight cognitively normal (NC) and 71 mild cognitive impairment (MCI) subjects completed a comprehensive cognitive battery for up to 5 years of follow-up. Composite indices of cognitive function were derived using a classic theoretical approach and exploratory factor analysis (EFA). Cognitive variables comprising each factor were averaged to form the EFA composite indices. Logistic regression was used to investigate whether these cognitive composites can reliably predict cognitive outcomes.

RESULTS

Neither method predicted decline in NC. The theoretical memory, executive, attention, and language composites and the EFA-derived "attention/executive" and "verbal memory" composites were significant predictors of decline in MCI. The best models achieved an area under the curve of 0.94 in MCI.

CONCLUSIONS

The theoretical and the statistically derived cognitive composite approaches are useful in predicting decline in MCI but not in NC.

Diffusion Tensor Imaging Predictors of Episodic Memory Decline in Healthy Elders at Genetic Risk for Alzheimer's Disease

OBJECTIVES

White matter (WM) integrity within the mesial temporal lobe (MTL) is important for episodic memory (EM) functioning. The current study investigated the ability of diffusion tensor imaging (DTI) in MTL WM tracts to predict 3-year changes in EM performance in healthy elders at disproportionately higher genetic risk for Alzheimer's disease (AD).

METHODS

Fifty-one cognitively intact elders (52% with family history (FH) of dementia and 33% possessing an Apolipoprotein E ε4 allelle) were administered the Rey Auditory Verbal Learning Test (RAVLT) at study entry and at 3-year follow-up. DTI scanning, conducted at study entry, examined fractional anisotropy and mean, radial and axial diffusion within three MTL WM tracts: uncinate fasciculus (UNC), cingulate-hippocampal (CHG), and fornix-stria terminalis (FxS). Correlations were performed between residualized change scores computed from RAVLT trials 1-5, immediate recall, and delayed recall scores and baseline DTI measures; MTL gray matter (GM) and WM volumes; demographics; and AD genetic and metabolic risk factors.

RESULTS

Higher MTL mean and axial diffusivity at baseline significantly predicted 3-year changes in EM, whereas baseline MTL GM and WM volumes, FH, and metabolic risk factors did not. Both ε4 status and DTI correlated with change in immediate recall.

CONCLUSIONS

Longitudinal EM changes in cognitively intact, healthy elders can be predicted by disruption of the MTL WM microstructure. These results are derived from a sample with a disproportionately higher genetic risk for AD, suggesting that the observed WM disruption in MTL pathways may be related to early neuropathological changes associated with the preclinical stage of AD. (JINS, 2016, 22, 1005-1015).

Interference Impacts Working Memory in Mild Cognitive Impairment

Mild cognitive impairment (MCI) is considered a transitional stage between healthy aging and dementia, specifically Alzheimer's disease (AD). The most common cognitive impairment of MCI includes episodic memory loss and difficulties in working memory (WM). Interference can deplete WM, and an optimal WM performance requires an effective control of attentional resources between the memoranda and the incoming stimuli. Difficulties in handling interference lead to forgetting. However, the interplay between interference and WM in MCI is not well-understood and needs further investigation. The current study investigated the effect of interference during a WM task in 20 MCIs and 20 healthy elder volunteers. Participants performed a delayed match-to-sample paradigm which consisted in two interference conditions, distraction and interruption, and one control condition without any interference. Results evidenced a disproportionate impact of interference on the WM performance of MCIs, mainly in the presence of interruption. These findings demonstrate that interference, and more precisely interruption, is an important proxy for memory-related deficits in MCI. Thus, the current findings reveal novel evidence regarding the causes of WM forgetting in MCI patients, associated with difficulties in the mechanisms of attentional control.

A diffusion model analysis of episodic recognition in preclinical individuals with a family history for Alzheimer's disease: The adult children study

OBJECTIVE

A family history of Alzheimer's disease (AD) increases the risk of developing AD and can influence the accumulation of well-established AD biomarkers. There is some evidence that family history can influence episodic memory performance even in cognitively normal individuals. We attempted to replicate the effect of family history on episodic memory and used a specific computational model of binary decision making (the diffusion model) to understand precisely how family history influences cognition. Finally, we assessed the sensitivity of model parameters to family history controlling for standard neuropsychological test performance.

METHOD

Across 2 experiments, cognitively healthy participants from the Adult Children Study completed an episodic recognition test consisting of high- and low-frequency words. The diffusion model was applied to decompose accuracy and reaction time (RT) into latent parameters which were analyzed as a function of family history.

RESULTS

In both experiments, individuals with a family history of AD exhibited lower recognition accuracy and this occurred in the absence of an apolipoprotein E (APOE) ε4 allele. The diffusion model revealed this difference was due to changes in the quality of information accumulation (the drift rate) and not differences in response caution or other model parameters. This difference remained after controlling for several standard neuropsychological tests.

CONCLUSIONS

These results confirm that the presence of a family history of AD confers a subtle cognitive deficit in episodic memory as reflected by decreased drift rate that cannot be attributed to APOE. This measure may serve as a novel cognitive marker of preclinical AD.

Alzheimer's Disease: Prototype of Cognitive Deterioration, Valuable Lessons to Understand Human Cognition

It is important for neurologists to become more familiar with neuropsychological evaluation for Alzheimer disease. The growth of this method in research, as an available, inexpensive, and noninvasive diagnostic approach, which can be administered even by non-specialist-trained examiners, makes this knowledge more necessary than ever. Such knowledge has a basic role in planning national programs in primary health care systems for prevention and early detection of Alzheimer disease. This is more crucial in developing countries, which have higher rates of dementia prevalence along with cardiovascular risk factors, lack of public knowledge about dementia, and limited social support. In addition compared to the neurological hard signs which are tangible and measurable, the concept of cognition seems to be more difficult for the neurologists to evaluate and for the students to understand. Dementia in general and Alzheimer's disease as the prototype of cognitive disorders specifically, play an important role to explore all domains of human cognition through its symptomatology and neuropsychological deficits.

Posteromedial hyperactivation during episodic recognition among people with memory decline: findings from the WRAP study

Episodic memory decline is one of the earliest preclinical symptoms of AD, and has been associated with an upregulation in the BOLD response in the prodromal stage (e.g. MCI) of AD. In a previous study, we observed upregulation in cognitively normal (CN) subjects with subclinical episodic memory decline compared to non-decliners. In light of this finding, we sought to determine if a separate cohort of Decliners will show increased brain activation compared to Stable subjects during episodic memory processing, and determine whether the BOLD effect was influenced by cerebral blood flow (CBF) or gray matter volume (GMV). Individuals were classified as a "Decliner" if scores on the Rey Auditory Verbal Learning Test (RAVLT) consistently fell ≥ 1.5 SD below expected intra- or inter-individual levels. FMRI was used to compare activation during a facial recognition memory task in 90 Stable (age = 59.1) and 34 Decliner (age = 62.1, SD = 5.9) CN middle-aged adults and 10 MCI patients (age = 72.1, SD = 9.4). Arterial spin labeling and anatomical T1 MRI were used to measure resting CBF and GMV, respectively. Stables and Decliners performed similarly on the episodic recognition memory task and significantly better than MCI patients. Compared to Stables, Decliners showed increased BOLD signal in the left precuneus on the episodic memory task that was not explained by CBF or GMV, familial AD risk factors, or neuropsychological measures. These findings suggest that subtle changes in the BOLD signal reflecting altered neural function may be a relatively early phenomenon associated with memory decline.

Sensitivity and specificity of executive function tests for Alzheimer's disease

Decline in executive function (EF) occurs early in Alzheimer's disease (AD) and can interfere with daily functioning. Unfortunately, little is known about the relative ability of traditional EF tests to detect these cognitive changes. Given that timely diagnosis and intervention are essential to improving functional outcome in this population, our aim was to identify the specific EF measures that best differentiated mild dementia from normal aging. Thirty-one patients with mild AD and 31 controls were administered 7 EF tests. Findings indicated significant between-group differences on all measures except Wisconsin Card Sorting Test. The remaining 6 tests displayed fair to good accuracy discriminating between AD cases and controls. Only category fluency and Tower of London test remained in the final regression model that yielded the highest AUC of 0.90, which was not statistically different from that of either test alone. Overall, most of the tests employed were valid for assessing mild EF disturbances. Specifically, the two measures can be used in isolation for quick screening or in combination to facilitate a more in-depth evaluation of EF performance. This study contributes to clinical field by testifying to the validity of various EF tests to identify AD-related compromises in this cognitive domain.

Clinical utility of the K-T cancellation test in a memory clinic population

BACKGROUND/AIM

The K-T cancellation test (K-T) has been validated as a measure of executive functions (EF) but its clinical utility has not yet been examined. This study aimed to validate K-T in a memory clinic setting by examining its capacity to discriminate older adults with normal cognition (NC) from those with mild cognitive impairment (MCI) and Alzheimer's disease (AD).

METHOD

K-T was administered to 120 NC subjects, 146 patients with MCI, and 93 patients with AD. A one-way analysis of covariance was used to compare the correct cancellations of K-T between the groups. Linear regressions were run to identify significant demographic predictors of K-T for NC subjects and to determine the equation to calculate z scores for all subjects. The area under the curve (AUC), sensitivity (Se), specificity (Sp), and positive (PPV) and negative (NPV) predictive values were assessed to compare the diagnostic performance between K-T and the Mini-Mental State Examination (MMSE) for discrimination between NC subjects and patients with cognitive impairment.

RESULTS

After adjusting for age, education, and gender, the groups were significantly different from each other regarding the number of correct cancellations of K-T, F(2, 353) = 116.6, p < .001, η(2)p = .40. Compared to the NC group (Z = 0, SD = 1), the mean z score was -1.52 for the MCI group and -2.53 for the AD group, suggesting impaired performance for the patient groups. K-T showed a better diagnostic performance for discrimination between the NC subjects and the patients with MCI (AUC = .83; 95% CI [.79, .88]; Se = .79; Sp = .74; PPV = .79; NPV = .74), compared to that of MMSE (AUC = .74, 95% CI [.68, .80]; Se = .68; Sp = .73; PPV = .79; NPV = .64).

CONCLUSION

The K-T cancellation test showed a good diagnostic performance in discriminating cognitively normal older adults from cognitively impaired patients. Our findings support the clinical utility of K-T in geriatric neuropsychological assessment for detection of early cognitive impairment.

Biomarker clusters are differentially associated with longitudinal cognitive decline in late midlife

The ability to detect preclinical Alzheimer's disease is of great importance, as this stage of the Alzheimer's continuum is believed to provide a key window for intervention and prevention. As Alzheimer's disease is characterized by multiple pathological changes, a biomarker panel reflecting co-occurring pathology will likely be most useful for early detection. Towards this end, 175 late middle-aged participants (mean age 55.9 ± 5.7 years at first cognitive assessment, 70% female) were recruited from two longitudinally followed cohorts to undergo magnetic resonance imaging and lumbar puncture. Cluster analysis was used to group individuals based on biomarkers of amyloid pathology (cerebrospinal fluid amyloid-β42/amyloid-β40 assay levels), magnetic resonance imaging-derived measures of neurodegeneration/atrophy (cerebrospinal fluid-to-brain volume ratio, and hippocampal volume), neurofibrillary tangles (cerebrospinal fluid phosphorylated tau181 assay levels), and a brain-based marker of vascular risk (total white matter hyperintensity lesion volume). Four biomarker clusters emerged consistent with preclinical features of (i) Alzheimer's disease; (ii) mixed Alzheimer's disease and vascular aetiology; (iii) suspected non-Alzheimer's disease aetiology; and (iv) healthy ageing. Cognitive decline was then analysed between clusters using longitudinal assessments of episodic memory, semantic memory, executive function, and global cognitive function with linear mixed effects modelling. Cluster 1 exhibited a higher intercept and greater rates of decline on tests of episodic memory. Cluster 2 had a lower intercept on a test of semantic memory and both Cluster 2 and Cluster 3 had steeper rates of decline on a test of global cognition. Additional analyses on Cluster 3, which had the smallest hippocampal volume, suggest that its biomarker profile is more likely due to hippocampal vulnerability and not to detectable specific volume loss exceeding the rate of normal ageing. Our results demonstrate that pathology, as indicated by biomarkers, in a preclinical timeframe is related to patterns of longitudinal cognitive decline. Such biomarker patterns may be useful for identifying at-risk populations to recruit for clinical trials.

Dysexecutive syndrome in amnesic mild cognitive impairment: a multicenter study

BACKGROUND

Executive functions (EF) in Alzheimer's disease (AD), classically related to the prefrontal cortex, have been forgotten in mild stages, given more importance to temporal lobe associated disorders, such as memory. The study of disexecutive syndrome (DS) has been relegated to advanced stages of the disease. Our goal is to demonstrate that EF are already present in amnesic mild cognitive impairment (aMCI). Furthermore, we are interested in knowing whether poor scores in EF tests are related to the progression to AD or another kind of dementia.

METHODS

We studied patients with aMCI (n = 81) and healthy controls (n = 142) from neurological departments of several centers of Basque Country with a cross-sectional design. Patients underwent a complete neuropsychological evaluation, neuroimaging testing APOE genotype and 3 year of prospective follow-up.

RESULTS

In the first visit, patients with aMCI showed more alterations in tests that evaluate EF such as Stroop, trail-making and categorical verbal fluency. More alterations were also found in NPI scale (P <0.05). Stroop and Trail-Making test were not associated with the future development of AD, but fluency (p = 0.01) and apathy (p = 0.031) did. No patient developed a different kind of dementia different from AD.

CONCLUSIONS

DS is a broad concept not confined to frontal lobes, and can be found in early stages of aMCI. DS impacts negatively on patient autonomy and may have prognostic value.

Executive function subcomponents and their relations to everyday functioning in healthy older adults

Everyday functioning and its executive functioning cognitive correlates (i.e., switching, inhibition, and updating) were investigated in healthy older adults (HOAs) using multiple methods of functional status. In addition to whether computerized experimental tasks would better dissociate these subcomponents than neuropsychological measures of executive functioning, we were also interested in the contributions of both experimental and neuropsychological measures of executive function subcomponents to functional abilities. Seventy HOAs (45 young-old and 25 old-old) and 70 younger adults completed executive function and neuropsychological tests. In addition to self- and informant questionnaires of functional abilities, HOAs completed two performance-based measures. An aging effect was found on all executive function measures. Old-old older adults and their informants did not report more functional difficulties but demonstrated more difficulties on performance-based measures than did young-old participants. For the HOAs, after controlling for age and education, the neuropsychological measures of executive functioning, but not experimental measures, explained a significant amount of variance in the informant-report and both performance-based measures. Updating measures differentially predicted performance-based measures, while switching was important for questionnaire and performance-based measures. The contribution of executive functioning to functional status when measured with experimental measures specifically designed to isolate the executive subcomponent was not as strong as hypothesized. Further research examining the value of isolating executive function subcomponents in neuropsychological assessment and the prediction of functional abilities in older adults is warranted.