Diagnostic Stability of Mild Cognitive Impairment, and Predictors of Reversion to Normal Cognitive Functioning

TMS-derived short afferent inhibition discriminates cognitive status in older adults without dementia

Aging is a complex and diverse biological process characterized by progressive molecular, cellular, and tissue damage, resulting in a loss of physiological integrity and heightened vulnerability to pathology. This biological diversity corresponds with highly variable cognitive trajectories, which are further confounded by genetic and environmental factors that influence the resilience of the aging brain. Given this complexity, there is a need for neurophysiological indicators that not only discern physiologic and pathologic aging but also closely align with cognitive trajectories. Transcranial Magnetic Stimulation (TMS) may have utility in this regard as a non-invasive brain stimulation tool that can characterize features of cortical excitability. Particularly, as a proxy for central cholinergic function, short-afferent inhibition (SAI) dysfunction is robustly associated with cognitive deficits in the latter stages of Alzheimer's Disease and Related Dementia (ADRD). In this study, we evaluated SAI in healthy young adults and older adults who, though absent clinical diagnoses, were algorithmically classified as cognitively normal (CN) or cognitively impaired (CI) according to the Jak/Bondi actuarial criteria. We report that SAI is preserved in the Old-CN cohort relative to the young adults, and SAI is significantly diminished in the Old-CI cohort relative to both young and CN older adults. Additionally, diminished SAI was significantly associated with impaired sustained attention and working memory. As a proxy measure for central cholinergic deficits, we discuss the potential value of SAI for discerning physiological and pathological aging.

Promising Strategies to Reduce the SARS-CoV-2 Amyloid Deposition in the Brain and Prevent COVID-19-Exacerbated Dementia and Alzheimer's Disease

The COVID-19 pandemic, caused by infection with the SARS-CoV-2 virus, is associated with cognitive impairment and Alzheimer's disease (AD) progression. Once it enters the brain, the SARS-CoV-2 virus stimulates accumulation of amyloids in the brain that are highly toxic to neural cells. These amyloids may trigger neurological symptoms in COVID-19. The meningeal lymphatic vessels (MLVs) play an important role in removal of toxins and mediate viral drainage from the brain. MLVs are considered a promising target to prevent COVID-19-exacerbated dementia. However, there are limited methods for augmentation of MLV function. This review highlights new discoveries in the field of COVID-19-mediated amyloid accumulation in the brain associated with the neurological symptoms and the development of promising strategies to stimulate clearance of amyloids from the brain through lymphatic and other pathways. These strategies are based on innovative methods of treating brain dysfunction induced by COVID-19 infection, including the use of photobiomodulation, plasmalogens, and medicinal herbs, which offer hope for addressing the challenges posed by the SARS-CoV-2 virus.

Interaction between Aβ and tau on reversion and conversion in mild cognitive impairment patients: After 2-year follow-up

Background

The role of amyloid-β (Aβ) and tau in reversion and conversion in patients with mild cognitive impairment (MCI) remains unclear. This study aimed to investigate the influence of cerebrospinal fluid (CSF) Aβ and tau on reversion and conversion and the temporal sequence of their pathogenicity in MCI patients.

Methods

179 MCI patients were recruited from the Alzheimer's Disease Neuroimaging Initiative database and classified into two groups based on cognitive changes after follow-up: reversal group (MCI to cognitively normal) and conversion group (MCI to Alzheimer's disease). CSF biomarkers and cognitive function were measured at baseline and 2-year follow-up. Partial correlation was used to analyze the association between CSF biomarkers and cognitive function, and multivariable logistic regression to identify independent risk factors for cognitive changes at baseline and 2-year follow-up. Receiver operating characteristic (ROC) curves were utilized to evaluate the predictive ability of these risk factors for cognitive changes.

Results

The differences in cognitive function and CSF biomarkers between the two groups remained consistent with baseline after 2-year follow-up. After controlling for confounding variables, there was still a correlation between CSF biomarkers and cognitive function at baseline and 2-year follow-up. Multivariable regression analysis found that at baseline, only Aβ level was independently associated with cognitive changes, while Aβ and tau were both predictive factors after 2-year follow-up. ROC curve analysis revealed that the combination of Aβ and tau [area under the curve (AUC) 0.91, sensitivity 84%, specificity 86%] in predicting cognitive changes after 2-year follow-up had better efficacy than baseline Aβ alone (AUC 0.81).

Conclusion

Aβ may precede Tau in causing cognitive changes, and the interaction between the two mediates cognitive changes in patients. This study provides new clinical evidence to support the view that Aβ pathology precedes tau pathology, which together contribute to the changes in cognitive function.

Predictors and outcomes of fluctuations in the clinical dementia rating scale

INTRODUCTION

Reversion, or change in cognitive status from impaired to normal, is common in aging and dementia studies, but it remains unclear what factors predict reversion.

METHODS

We investigated whether reverters, defined as those who revert from a Clinical Dementia Rating® (CDR®) scale score of 0.5 to CDR 0) differed on cognition and biomarkers from unimpaired participants (always CDR 0) and impaired participants (converted to CDR > 0 and had no reversion events). Models evaluated relationships between biomarker status, apolipoprotein E (APOE) ε4 status, and cognition. Additional models described predictors of reversion and predictors of eventual progression to CDR > 0.

RESULTS

CDR reversion was associated with younger age, better cognition, and negative amyloid biomarker status. Reverters that eventually progressed to CDR > 0 had more visits, were older, and were more likely to have an APOE ε4 allele.

DISCUSSION

CDR reversion occupies a transitional phase in disease progression between cognitive normality and overt dementia. Reverters may be ideal candidates for secondary prevention Alzheimer's disease (AD) trials.

HIGHLIGHTS

Reverters had more longitudinal cognitive decline than those who remained cognitively normal. Predictors of reversion: younger age, better cognition, and negative amyloid biomarker status. Reverting from CDR 0.5 to 0 is a risk factor for future conversion to CDR > 0. CDR reversion may be a transitional phase in Alzheimer's Disease progression. CDR reverters may be ideal for Alzheimer's disease secondary prevention trials.

Results of objective brushing data recorded from a powered toothbrush used by elderly individuals with mild cognitive impairment related to values for oral health

OBJECTIVES

The study aimed to investigate how the objective use of a powered toothbrush in frequency and duration affects plaque index, bleeding on probing, and periodontal pocket depth ≥ 4 mm in elderly individuals with MCI. A second aim was to compare the objective results with the participants' self-estimated brush use.

MATERIALS AND METHODS

Objective brush usage data was extracted from the participants' powered toothbrushes and related to the oral health variables plaque index, bleeding on probing, and periodontal pocket depth ≥ 4 mm. Furthermore, the objective usage data was compared with the participants' self-reported brush usage reported in a questionnaire at baseline and 6- and 12-month examination.

RESULTS

Out of a screened sample of 213 individuals, 170 fulfilled the 12-month visit. The principal findings are that despite the objective values registered for frequency and duration being lower than the recommended and less than the instructed, using powered toothbrushes after instruction and information led to improved values for PI, BOP, and PPD ≥ 4 mm in the group of elderly with MIC.

CONCLUSIONS

Despite lower brush frequency and duration than the generally recommended, using a powered toothbrush improved oral health. The objective brush data recorded from the powered toothbrush correlates poorly with the self-estimated brush use.

CLINICAL RELEVANCE

Using objective brush data can become one of the factors in the collaboration to preserve and improve oral health in older people with mild cognitive impairment.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05941611, retrospectively registered 11/07/2023.

Analysis of Convergent Validity of Performance-Based Activities of Daily Living Assessed by PA-IADL Test in Relation to Traditional (Standard) Cognitive Assessment to Identify Older Adults with Mild Cognitive Impairment

Difficulty in performing instrumental activities of daily living (IADLs) is currently considered an important indicator of cognitive impairment in the elderly. A non-experimental case-control investigation was conducted to assess the convergent validity of the PA-IADL with traditional (standard) cognitive assessment tests in its ability to identify adults with mild cognitive impairment. The analysis of the data was carried out by means of various multivariate statistical tests, and the sequence in its execution led to the conclusion that 8 of the 12 Tasks that make up the PA-IADL allow for the identification of people with mild cognitive impairment (MCI) to the same extent as traditional cognitive assessment tests and regardless of age. Age was found to be a moderating variable in the performance of the eight tasks; however, the results allow us to hypothesize that people with MCI experience a significant decline when it happens but thereafter, the deterioration that occurs does so at the same rate as the deterioration experienced by healthy people. They also allow us to hypothesize that the difference in the cognitive skills required by the eight functional tasks, and therefore also in the cognitive skills required by the traditional (standard) tests of a person with MCI compared to a person of the same age without MCI (Healthy), is approximately 10 years. These hypotheses have remarkable relevance and should be tested via longitudinal research. In the meantime, the results highlight the importance of the IADL assessment for the diagnosis of MCI as a complement to the standard cognitive assessment.

Grey matter volume and CSF biomarkers predict neuropsychological subtypes of MCI

There is increasing evidence of different subtypes of individuals with mild cognitive impairment (MCI). An important line of research is whether neuropsychologically-defined subtypes have distinct patterns of neurodegeneration and cerebrospinal fluid (CSF) biomarker composition. In our study, we demonstrated that MCI participants of the ADNI database (N = 640) can be discriminated into 3 coherent neuropsychological subgroups. Our clustering approach revealed amnestic MCI, mixed MCI, and cluster-derived normal subgroups. Furthermore, classification modeling revealed that specific predictive features can be used to differentiate amnestic and mixed MCI from cognitively normal (CN) controls: CSF Aβ142 concentration for the former and CSF Aβ1-42 concentration, tau concentration as well as grey matter atrophy (especially in the temporal and occipital lobes) for the latter. In contrast, participants from the cluster-derived normal subgroup exhibited an identical profile to CN controls in terms of cognitive performance, brain structure, and CSF biomarker levels. Our comprehensive data analytics strategy provides further evidence that multimodal neuropsychological subtyping is both clinically and neurobiologically meaningful.

Screening strategies and dynamic risk prediction models for Alzheimer's disease

BACKGROUND

Characterizing the progression from Mild cognitive impairment (MCI) to Alzheimer's disease (AD) is essential for early AD prevention and targeted intervention. Our goal was to construct precise screening schemes for individuals with different risk of AD and to establish prognosis models for them.

METHODS

We constructed a retrospective cohort by reviewing individuals with baseline diagnosis of MCI and at least one follow-up visits between November 2005 and May 2021. They were stratified into high-risk and low-risk groups with longitudinal cognitive trajectory. Then, we established a screening framework and obtained optimal screening strategies for two risk groups. Cox and random survival forest (RSF) models were developed for dynamic prognosis prediction.

RESULTS

In terms of screening strategies, the combination of Clinical Dementia Rating Sum of Boxes (CDRSB) and hippocampus volume was recommended for the high-risk MCI group, while the combination of Alzheimer's Disease Assessment Scale Cognitive 13 items (ADAS13) and FAQ was recommended for low-risk MCI group. The concordance index (C-index) of the Cox model for the high-risk group was 0.844 (95% CI: 0.815-0.873) and adjustments for demographic information and APOE ε4. The RSF model incorporating longitudinal ADAS13, FAQ, and demographic information and APOE ε4 performed for the low-risk group.

CONCLUSION

This precise screening scheme will optimize allocation of medical resources and reduce the economic burden on individuals with low risk of MCI. Moreover, dynamic prognosis models may be helpful for early identification of individuals at risk and clinical decisions, which will promote the secondary prevention of AD.

Effect of Music Interventions on Cognitive Function in Older Adults With Mild Cognitive Impairment: A Systematic Review

The purpose of the current systematic review was to examine the effects of music interventions on cognitive function in older adults with mild cognitive impairment (MCI). A systematic search of CINAHL, PubMed, PsycINFO, and Web of Science databases was performed. Studies examining the effects of music interventions on cognitive function in older adults with MCI were included. Narrative synthesis for cognitive outcomes postintervention was performed. A total of 11 articles met inclusion criteria. Music interventions significantly improved global cognitive function, verbal fluency, executive function, and spatial function in older adults with MCI. Included studies were heterogeneous in terms of the type of intervention, cognitive assessment tool, and intervention duration. Six studies were at risk of bias due to missing data and confounding factors. Our findings suggest that music interventions can be an effective strategy to improve cognitive function for older adults with MCI. However, findings should be interpreted with caution. More rigorous studies with various types of music interventions investigating cognitive domain-specific effects are needed. [Research in Gerontological Nursing, 16(5), 259-268.].

Fluctuations in Cognitive Test Scores and Loss to Follow-Up in Community-Dwelling Older Adults: The IRIDE Cohort Study

INTRODUCTION

We examined the relationship between previous fluctuations in Mini-Mental State Examination (MMSE) scores, future changes in MMSE scores, and attrition from follow-up surveys, which helps in a more comprehensive interpretation of repeatedly collected MMSE scores.

METHODS

This 4-year longitudinal study included 2,073 community-dwelling older adults aged ≥65 years in Japan. The MMSE was administered at baseline (T0), 2 years (T1), and 4 years (T2) follow-up. We performed multinomial logistic regression analysis with the dependent variable, indicating the change in MMSE score from T1 to T2 (categorized as increase, no change [reference category], and decrease) and attrition at T2. The independent variables included the change in MMSE scores from T0 to T1 and MMSE scores at T0 and T1.

RESULTS

The mean MMSE score was 29 across the three time points. A one-point decrease in MMSE score from T0 to T1 was associated with 79% (95% confidence interval: 1.62, 1.97) higher odds of an increase in MMSE score from T1 to T2 and 28% (1.17, 1.40) higher odds of attrition at T2. A one-point decrement in the MMSE score at T0 and T1 was also associated with an increase in the MMSE score from T1 to T2 and attrition at T2.

CONCLUSION

Focusing on cognitive fluctuation for 2 years, rather than cognitive function at a point in time, would have no remarkable advantage when focusing on future cognitive function and attrition. Our results emphasize the need for further studies to identify factors that distinguish between those who continue to attend follow-up surveys and show improvements in cognitive test scores and those who drop out.

Analysis of Why Alzheimer's Dementia Never Spontaneously Reverses, Suggests the Basis for Curative Treatment

A paradox regarding Alzheimer's dementia (AD) and mild cognitive impairment (MCI) is thats spontaneous cure of AD has never been reported, whereas spontaneous cure for MCI occurs fequently. This article analyzes what accounts for this difference. It holds that it is not merely because, for any condition, a stage is reached beyond which it cannot be reversed, since even widely metastatic cancer would be curable were there effective chemotherapy and rheumatoid arthritis became controllable when immune-suppressant treatment was introduced; thus, so could AD be reversible via effective therapy. The analysis presented leads to an explanation of the paradox that is in four categories: (1) levels of transforming growth factor-β are significantly reduced after the transition from MCI to AD; (2) levels of Wnt/β-catenin are significantly reduced after the transition; (3) there is altered epidermal-mesenchymal transition (EMT) in neurons after the transition; (4) there may be risk factors that are either newly operative or pre-existing but worsened at the time of transition, that are particular to individual patients. It is suggested that addressing and ameliorating all of those four categories might cure AD. Medications to address and ameliorate each of the four categories are described.

Acquisition and consolidation of verbal learning and episodic memory as predictors of the conversion from mild cognitive impairment to probable Alzheimer's disease

Verbal episodic memory tests assess memory performance using total learning scores. The analysis of inter-trial indices such as gained (GA) and lost (LA) access can provide additional information on the acquisition and consolidation processes. The main objetive was to determine whether the GA and LA indices, derived from a word-list verbal episodic memory test are useful for predicting cognitive impairment in aging. 60 older people aged was divided into 3 groups: cognitively healthy, stable Mild Cognitive Impairment (MCI) and MCI converting to probable Alzheimer's disease (MCI-conv). The results showed that GA and LA measures are independent from the traditional measures -total score of correct answers-. Logistic regression showed that these values are predictive of the conversion over time and could be a cognitive marker of conversion from MCI to AD. This suggests that the GA index, which shows acquisition processes in word-list tests, may be a marker of cognitive impairment.

Use of a powered toothbrush to improve oral health in individuals with mild cognitive impairment

OBJECTIVES

The aim of the study is to investigate whether the use of a powered toothbrush could maintain oral health by reducing the dental plaque (PI), bleeding on probing (BOP), and periodontal pocket depth (PPD) ≥4 mm in a group of individuals with MCI and also if changes in oral health affect various aspects of quality of life.

BACKGROUND

People with cognitive impairment tend to have poor oral hygiene and poorer Quality of life. In the present study, the participants were asked to use a powered toothbrush for at least 2 min morning and evening and no restrictions were given against the use of other oral care products. The participant survey conducted at each examination demonstrated that 61.2% of participants at baseline claimed to have experience of using a powered toothbrush, 95.4% at 6 months and 95% after 12 months. At the same time, the use of manual toothbrushes dropped from 73.3% to 44.7% from baseline to the 12-month check-up. This shows that several participants continue to use the manual toothbrush in parallel with the powered toothbrush, but that there is a shift towards increased use of the powered toothbrush. Removal of dental biofilm is essential for maintaining good oral health. We investigated whether using a powered toothbrush reduces the presence of dental plaque, bleeding on probing and periodontal pockets ≥4 mm in a group of older individuals with mild cognitive impairment.

MATERIALS AND METHODS

Two hundred and thirteen individuals with the mean age of 75.3 years living without official home care and with a Mini-Mental State Examination (MMSE) score between 20 and 28 and a history of memory problems in the previous six months were recruited from the Swedish site of a multicenter project, Support Monitoring And Reminder Technology for Mild Dementia (SMART4MD) and screened for the study. The individuals received a powered toothbrush and thorough instructions on how to use it. Clinical oral examinations and MMSE tests were conducted at baseline, 6 and 12 months.

RESULTS

One hundred seventy participants, 36.5% women and 63.5% men, completed a 12-month follow-up. The use of a powered toothbrush resulted, for the entire group, in a significant decrease in plaque index from 41% at baseline to 31.5% after 12 months (P < .000). Within the same time frame, the values for bleeding on probing changed from 15.1% to 9.9% (P < .000) and the percentage of probing pocket depths ≥4 mm from 11.5% to 8.2% (P < .004). The observed improvements in the Oral Health Impact Profile 14 correlate with the clinical improvements of oral health.

CONCLUSION

The use of a powered toothbrush was associated with a reduction of PI, BOP and PPD over 12 months even among individuals with low or declining MMSE score. An adequately used powered toothbrush maintain factors that affect oral health and oral health-related Quality of Life in people with mild cognitive impairment.

Air pollution and plasma amyloid beta in a cohort of older adults: Evidence from the Ginkgo Evaluation of Memory study

Air pollution has been linked to Alzheimer's disease and related dementias (ADRD), but the mechanisms connecting air pollution to ADRD have not been firmly established. Air pollution may cause oxidative stress and neuroinflammation and contribute to the deposition of amyloid beta (Aβ) in the brain. We examined the association between fine particulate matter<2.5 μm in diameter (PM2.5), particulate matter<10 μm in diameter (PM10), nitrogen dioxide (NO2), and plasma based measures of Aβ1-40, Aβ1-42 and Aβ1-42/Aβ1-40 using data from 3044 dementia-free participants of the Ginkgo Evaluation of Memory Study (GEMS). Air pollution exposures were estimated at residential addresses that incorporated address histories dating back to 1980, resulting in one-, five-, 10- and 20- year exposure averages. Aβ was measured at baseline (2000-2002) and then again at the end of the study (2007-2008) allowing for linear regression models to assess cross-sectional associations and linear random effects models to evaluate repeated measures. After adjustment for socio-demographic and behavioral covariates, we found small positive associations between each air pollutant and Aβ1-40 but no association with Aβ1-42 or the ratio measures in cross sectional analysis. In repeat measures analysis, we found larger positive associations between each air pollutant and all three outcomes. We observed a 4.43% (95% CI 3.26%, 5.60%) higher Aβ1-40 level, 9.73% (6.20%, 13.38%) higher Aβ1-42 and 1.57% (95% CI: 0.94%, 2.20%) higher Aβ1-42/Aβ1-40 ratio associated with a 2 µg/m3 higher 20-year average PM2.5. Associations with other air pollutants were similar. Our study contributes to the broader evidence base on air pollution and ADRD biomarkers by evaluating longer air pollution exposure averaging periods to better mimic disease progression and provides a modifiable target for ADRD prevention.

Mild Cognitive Impairment, Reversion Rates, and Associated Factors: Comparison of Two Diagnostic Approaches

BACKGROUND

As mild cognitive impairment (MCI) is typically used to identify prodromal stages of dementia, it is essential to identify MCI criteria with high diagnostic stability and prediction of dementia. Moreover, further investigation into pinpointing key factors for reversion is required to foresee future prognosis of MCI patients accurately.

OBJECTIVE

To explore disparities in diagnostic stability by examining reversion rates produced by two operationalizations of the MCI definition: the widely applied Petersen criteria and a version of the Neuropsychological (NP) criteria and to identify cognitive, lifestyle, and health related factors for reversion.

METHODS

MCI was retrospectively classified in a sample from the Swedish community-based study Good Aging in Skåne with the Petersen criteria (n = 744, median follow-up = 7.0 years) and the NP criteria (n = 375, median follow-up, 6.7 years), respectively. Poisson regression models estimated the effect of various factors on the likelihood of incident reversion.

RESULTS

Reversion rates were 323/744 (43.4%, 95% confidence intervals (CI): 39.8; 47.0) and 181/375 (48.3% 95% CI: 43.2; 53.5) for the Petersen criteria and NP criteria, respectively. Participants with impairment in a single cognitive domain, regular alcohol consumption, living with someone, older age, and lower body mass index had a higher likelihood of reverting to normal.

CONCLUSION

Reversion rates were similar for Petersen and NP criteria indicating that one definition is not superior to the other regarding diagnostic stability. Additionally, the results highlight important aspects such as multiple domain MCI, cohabitation, and the role of alcohol on predicting the trajectory of those diagnosed with MCI.

Mild Cognitive Impairment: Diagnosis and Subtypes

Mild cognitive impairment (MCI) is a clinical diagnosis based on subjective cognitive decline, objective cognitive impairment, and relative preservation of activities of daily living. The diagnosis may be established via clinical interview, collateral history from an informant, and psychometric examination. Various consensus groups have proposed criteria for MCI in Alzheimer's disease (AD), Parkinson's disease, dementia with Lewy bodies, and vascular cognitive impairment. These diagnostic criteria have subtle but important differences. Criteria for subjective decline vary according to whether memory is impaired or whether impairment in any cognitive domain is sufficient. There are also differences with respect to whether the subjective decline is noted by the patient, a carer, or a clinician. The precise thresholds for classifying objective cognitive impairment also vary between various diagnostic criteria. There are also differences in the description of functional abilities. Once established, the diagnosis of MCI may be refined to 1 of 4 subtypes based on the pattern of cognitive impairment. The 4 subtypes are defined according to whether or not memory is impaired and whether 1 or more cognitive domains are impaired. Once a diagnosis of MCI has been made, the patient and the family should be counseled about social and legal implications as well as strategies for reducing the risk of progression to dementia. The main utilities of MCI as a nosology are to understand the natural history of neurodegenerative disorders such as AD, to identify those at increased risk of progressing to develop dementia, and to identifying individuals for putative treatments.

Selenoprotein P Concentrations in the Cerebrospinal Fluid and Serum of Individuals Affected by Amyotrophic Lateral Sclerosis, Mild Cognitive Impairment and Alzheimer’s Dementia

Selenoprotein P, a selenium-transporter protein, has been hypothesized to play a role in the etiology of neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and Alzheimer’s dementia (AD). However, data in humans are scarce and largely confined to autoptic samples. In this case–control study, we determined selenoprotein P concentrations in both the cerebrospinal fluid (CSF) and the serum of 50 individuals diagnosed with ALS, 30 with AD, 54 with mild cognitive impairment (MCI) and of 30 controls, using sandwich enzyme-linked immunosorbent assay (ELISA) methods. We found a positive and generally linear association between CSF and serum selenoprotein P concentrations in all groups. CSF selenoprotein P and biomarkers of neurodegeneration were positively associated in AD, while for MCI, we found an inverted-U-shaped relation. CSF selenoprotein P concentrations were higher in AD and MCI than in ALS and controls, while in serum, the highest concentrations were found in MCI and ALS. Logistic and cubic spline regression analyses showed an inverse association between CSF selenoprotein P levels and ALS risk, and a positive association for AD risk, while an inverted-U-shaped relation with MCI risk emerged. Conversely, serum selenoprotein P concentrations were positively associated with risk of all conditions but only in their lower range. Overall, these findings indicate some abnormalities of selenoprotein P concentrations in both the central nervous system and blood associated with ALS and neurocognitive disorders, though in different directions. These alterations may reflect either phenomena of etiologic relevance or disease-induced alterations of nutritional and metabolic status.

Cognitive reserve and risk of mobility impairment in older adults

BACKGROUND

Cognitive reserve (CR) protects against cognitive decline and dementia but its relation to mobility impairment has not been established. To address this important gap in the literature, we conducted a longitudinal investigation to test the hypothesis that higher baseline CR was associated with a lower risk of developing mobility impairment in older adults.

METHODS

Participants were dementia-free older adults who received brain magnetic resonance imaging and had gait speed assessments during follow-up. Using the residuals approach, CR was computed as the variance in the Modified Mini-Mental Status Examination total score, that was left after accounting for structural brain integrity, education, and race. Mobility impairment was defined using a validated cutoff score in gait speed of 0.8 m/s. Logistic regression models using general estimating equations were utilized to examine longitudinal associations between baseline CR and the risk of developing mobility impairment across repeated assessments.

RESULTS

Of the participants (n = 237; mean age = 82 years; %female = 56%) who were free of mobility impairment at baseline, 103 developed mobility impairment during follow-up (mean = 3.1 years). Higher CR at baseline was associated with a lower risk of developing incident mobility impairment-odds ratio (OR) = 0.819, 0.67-0.98, p = 0.038 (unadjusted); OR = 0.815, 0.67-0.99, p = 0.04 (adjusted for socio-demographic variables and depression); OR = 0.819, 0.68-0.88, p = 0.035 (adjusted for illness history); OR = 0.824, 0.68-0.99, p = 0.045 (adjusted for white matter hyperintensities); OR = 0.795, 0.65-0.95, p = 0.016 (adjusted for falls history).

CONCLUSION

Higher CR at baseline was protective against developing incident mobility impairment during follow-up among community-residing older adults.

The Clinical Course of Early and Late Mild Cognitive Impairment

Introduction

Amnestic mild cognitive impairment (MCI) can be classified as either early MCI (EMCI) or late MCI (LMCI) according to the severity of memory impairment. The aim of this study was to compare the prognosis and clinical course between EMCI and LMCI.

Methods

Between January 2009 and December 2017, a total of 418 patients with MCI and 146 subjects with normal cognition were recruited from a memory clinic. All the patients received at least two series of neuropsychological evaluations each year and were categorized as either EMCI or LMCI according to Alzheimer's Disease Neuroimaging Initiative 2 (ADNI2) criteria.

Results

In total, our study included 161 patients with EMCI, 258 with LMCI, and 146 subjects with normal cognition as controls (NCs). The mean follow-up duration was 3.55 ± 2.18 years (range: 1–9). In a first-year follow-up assessment, 54 cases (32.8%) of EMCI and 16 (5%) of LMCI showed a normal cognitive status. There was no significant difference between the first year EMCI reverter and NCs in terms of dementia-free survival and further cognitive decline. However, first-year LMCI reverters still had a higher risk of cognitive decline during the following evaluations. Until the last follow-up, annual dementia conversion rates were 1.74, 4.33, and 18.6% in the NC, EMCI, and LMCI groups, respectively. The EMCI and LMCI groups showed a higher rate of progression to dementia (log-rank test, p < 0.001) than normal subjects. Compared with NCs, patients in the LMCI group showed a significantly faster annual decline in global cognition [annual rate of change for the mini-mental status examination (MMSE) score: −1.035, p < 0.001]) and all cognitive domains, while those in the EMCI group showed a faster rate of decline in global cognitive function (annual rate of change for the MMSE score: −0.299, p = 0.001).

Conclusion

It is important to arrange follow-up visits for patients with MCI, even in the EMCI stage. One-year short-term follow-up may provide clues about the progression of cognitive function and help to identify relatively low-risk EMCI subjects.

Progression to Dementia or Reversion to Normal Cognition in Mild Cognitive Impairment as a Function of Late-Onset Neuropsychiatric Symptoms

BACKGROUND AND OBJECTIVES

Mild cognitive impairment (MCI) is an at-risk state for dementia; however, not all individuals with MCI transition to dementia, and some revert to normal cognition (NC). Here, we investigate whether mild behavioral impairment (MBI), the late-life onset of persistent neuropsychiatric symptoms (NPS), improves the prognostic specificity of MCI.

METHODS

Participants with MCI from the National Alzheimer's Coordinating Center Uniform Data Set were included. NPS were operationalized with the Neuropsychiatric Inventory Questionnaire to identify participants without NPS and those with MBI (persistent, late-onset NPS). Individuals with late-onset NPS not meeting the MBI persistence criterion (NPS_NOT_MBI) were retained for secondary analyses. Progression to dementia, stable MCI, and reversion to NC after 3 years of follow-up were defined per National Institute on Aging-Alzheimer's Association and Petersen criteria.

RESULTS

The primary sample consisted of 739 participants (NPS- n = 409 and MBI+ n = 330; 75.16 ± 8.6 years old, 40.5% female). After 3 years, 238 participants (33.6%) progressed to dementia, and 90 (12.2%) reverted to NC. Compared to participants without NPS, participants with MBI were significantly more likely to progress to dementia (adjusted odds ratio [AOR] 2.13, 95% CI 1.52-2.99), with an annual progression rate of 14.7% (vs 8.3% for participants with MCI without NPS). Compared to participants without NPS, participants with MBI were less likely to revert to NC (AOR 0.48, 95% CI 0.28-0.83, 2.5% vs 5.3% annual reversion rate). The NPS_NOT_MBI group (n = 331, 76.5 ± 8.6 years old, 45.9% female) were more likely to progress to dementia (AOR 2.18, 95% CI 1.56-3.03, 14.3% annual progression rate) but not less likely to revert to NC than those without NPS. Accordingly, both NPS_NOT_MBI and MBI+ participants had lower Mini-Mental State Examination scores than NPS- participants after 3 years.

DISCUSSION

Late-onset NPS improve the specificity of MCI as an at-risk state for progression to dementia. However, only persistent late-onset NPS are associated with a lower likelihood of reversion to NC, with transient NPS (i.e., NPS_NOT_MBI) not differing from the NPS- group. Clinical prognostication can be improved by incorporating late-onset NPS, especially those that persist (i.e., MBI), into risk assessments. Clinical trials may benefit from enrichment with these higher-risk participants with MCI.

CoGNIT Automated Tablet Computer Cognitive Testing in Patients With Mild Cognitive Impairment: Feasibility Study

Background

Early diagnosis of cognitive disorders is becoming increasingly important. Limited resources for specialist assessment and an increasing demographical challenge warrants the need for efficient methods of evaluation. In response, CoGNIT, a tablet app for automatic, standardized, and efficient assessment of cognitive function, was developed. Included tests span the cognitive domains regarded as important for assessment in a general memory clinic (memory, language, psychomotor speed, executive function, attention, visuospatial ability, manual dexterity, and symptoms of depression).

Objective

The aim of this study was to assess the feasibility of automatic cognitive testing with CoGNIT in older patients with symptoms of mild cognitive impairment (MCI).

Methods

Patients older than 55 years with symptoms of MCI (n=36) were recruited at the research clinic at the Blekinge Institute of Technology (BTH), Karlskrona, Sweden. A research nurse administered the Mini-Mental State Exam (MMSE) and the CoGNIT app on a tablet computer. Technical and testing issues were documented.

Results

The test battery was completed by all 36 patients. One test, the four-finger–tapping test, was performed incorrectly by 42% of the patients. Issues regarding clarity of instructions were found in 2 tests (block design test and the one finger-tapping test). Minor software bugs were identified.

Conclusions

The overall feasibility of automatic cognitive testing with the CoGNIT app in patients with symptoms of MCI was good. The study highlighted tests that did not function optimally. The four-finger–tapping test will be discarded, and minor improvements to the software will be added before further studies and deployment in the clinic.

The role of brain-derived neurotrophic factor and the neurotrophin receptor p75NTR in age-related brain atrophy and the transition to Alzheimer's disease

Alzheimer's disease is a neurodegenerative condition that is potentially mediated by synaptic dysfunction before the onset of cognitive impairments. The disease mostly affects elderly people and there is currently no therapeutic which halts its progression. One therapeutic strategy for Alzheimer's disease is to regenerate lost synapses by targeting mechanisms involved in synaptic plasticity. This strategy has led to promising drug candidates in clinical trials, but further progress needs to be made. An unresolved problem of Alzheimer's disease is to identify the molecular mechanisms that render the aged brain susceptible to synaptic dysfunction. Understanding this susceptibility may identify drug targets which could halt, or even reverse, the disease's progression. Brain derived neurotrophic factor is a neurotrophin expressed in the brain previously implicated in Alzheimer's disease due to its involvement in synaptic plasticity. Low levels of the protein increase susceptibility to the disease and post-mortem studies consistently show reductions in its expression. A desirable therapeutic approach for Alzheimer's disease is to stimulate the expression of brain derived neurotrophic factor and potentially regenerate lost synapses. However, synthesis and secretion of the protein are regulated by complex activity-dependent mechanisms within neurons, which makes this approach challenging. Moreover, the protein is synthesised as a precursor which exerts the opposite effect of its mature form through the neurotrophin receptor p75NTR. This review will evaluate current evidence on how age-related alterations in the synthesis, processing and signalling of brain derived neurotrophic factor may increase the risk of Alzheimer's disease.

"ET Plus": Instability of the Diagnosis During Prospective Longitudinal Follow-up of Essential Tremor Cases

Background: A recent consensus statement introduced the term "ET plus". Although investigators have quantified the prevalence of ET plus in cross-sectional studies, patients with ET plus have not been tracked longitudinally; hence, there is no understanding of its stability over time. Methods: We present prospective, longitudinal phenotypic data on an ET cohort that was followed regularly at 18-month intervals (T1, T2, T3, T4) for up to 64 months. We assigned an ET or ET plus diagnosis to each case at each time interval. Results: There were 201 participants at baseline. The proportion with ET plus increased from 58.7% at baseline to 72.1% at T4 (p = 0.046). Of 172 (85.6%) who received a diagnosis of ET plus at one or more time intervals, the diagnosis was unstable (e.g., with reversion) in 62 (36.0%). We also assessed the stability of the clinical features of ET plus. Rest tremor was the most unstable clinical feature of ET plus; it was present in 59 participants, among whom it reverted from present to absent in 23 (39.0%). By contrast, for "memory impairment" (i.e., either mild cognitive impairment or dementia), the proportion who reverted from present to absent was only 21.3%. Conclusion: These data support our two a priori hypotheses: (1) the prevalence of ET plus would increase progressively, as it likely represents a more advanced stage of ET, and (2) the ET plus diagnosis would not be stable over time, as cases would fluctuate with respect to their phenotypic features and their assigned diagnoses.

Variability in Cognitive Performance on Mobile Devices Is Sensitive to Mild Cognitive Impairment: Results From the Einstein Aging Study

Background and Objective: Within-person variability in cognitive performance has emerged as a promising indicator of cognitive health with potential to distinguish normative and pathological cognitive aging. We use a smartphone-based digital health approach with ecological momentary assessments (EMA) to examine differences in variability in performance among older adults with mild cognitive impairment (MCI) and those who were cognitively unimpaired (CU). Method: A sample of 311 systematically recruited, community-dwelling older adults from the Einstein Aging Study (Mean age = 77.46 years, SD = 4.86, Range = 70-90; 67% Female; 45% Non-Hispanic White, 40% Non-Hispanic Black) completed neuropsychological testing, neurological assessments, and self-reported questionnaires. One hundred individuals met Jak/Bondi criteria for MCI. All participants performed mobile cognitive tests of processing speed, visual short-term memory binding, and spatial working memory on a smartphone device up to six times daily for 16 days, yielding up to 96 assessments per person. We employed heterogeneous variance multilevel models using log-linear prediction of residual variance to simultaneously assess cognitive status differences in mean performance, within-day variability, and day-to-day variability. We further tested whether these differences were robust to the influence of environmental contexts under which assessments were performed. Results: Individuals with MCI exhibited greater within-day variability than those who were CU on ambulatory assessments that measure processing speed (p < 0.001) and visual short-term memory binding (p < 0.001) performance but not spatial working memory. Cognitive status differences in day-to-day variability were present only for the measure of processing speed. Associations between cognitive status and within-day variability in performance were robust to adjustment for sociodemographic and contextual variables. Conclusion: Our smartphone-based digital health approach facilitates the ambulatory assessment of cognitive performance in older adults and the capacity to differentiate individuals with MCI from those who were CU. Results suggest variability in mobile cognitive performance is sensitive to MCI and exhibits dissociative patterns by timescale and cognitive domain. Variability in processing speed and visual short-term memory binding performance may provide specific detection of MCI. The 16-day smartphone-based EMA measurement burst offers novel opportunity to leverage digital technology to measure performance variability across frequent assessments for studying cognitive health and identifying early clinical manifestations of cognitive impairment.

Magnetic Resonance Imaging in Stable Mild Cognitive Impairment, Prodromal Alzheimer's Disease, and Prodromal Dementia with Lewy Bodies

INTRODUCTION

Fifteen percent of people with mild cognitive impairment (MCI) will progress to dementia within 2 years. There is increasing focus on the evaluation of biomarkers which point towards the underlying pathology. This enables better prediction of clinical outcomes. Early diagnosis of the dementia subtype is crucial for appropriate management and accurate prognosis. The aim of this study was to compare MRI measures in stable mild cognitive impairment patients (stable-MCI), prodromal Alzheimer's disease (pro-AD), and prodromal dementia with Lewy bodies (pro-DLB).

METHODS

Out of 1,814 patients assessed in Essex memory clinic between 2002 and 2017, 424 had MCI at baseline with follow-up data. All patients underwent comprehensive clinical and cognitive assessment at each assessment. MRI scans were acquired at patients' baseline assessment, corresponding to the time of initial MCI clinical diagnosis. Patients were grouped according to their diagnosis at the end of follow-up. All baseline scans were visually rated according to established rating scales for medial temporal atrophy (MTA), global cortical atrophy (GCA), and white matter lesions (WMLs).

RESULTS

MRI scans were available for 28 pro-DLB patients and were matched against 27 pro-AD and 28 stable-MCI patients for age, sex, and education. The mean follow-up duration was 34 months for the pro-AD group, 27 months for the pro-DLB group, and 21 months for the stable-MCI group. MTA scores were significantly greater in pro-AD patients compared to pro-DLB (p = 0.047) and stable-MCI patients (p = 0.012). There was no difference on GCA or WMLs between pro-AD, pro-DLB, and stable-MCI.

CONCLUSIONS

This study indicates that a simple visual rating of MTA at the stage of MCI already differs at a group level between patients that progress to AD, DLB, or continue to be stable-MCI. This could aid clinicians to differentiate between MCI patients who are likely to develop AD, versus those who might progress to DLB or remain stable.

Processing speed is affected by early impairment in kidney function in the general elder population

Background

Chronic kidney disease, cardiovascular disease, and cognitive dysfunction are common in the elder population. There is evidence of a connection between these conditions, possibly by a shared vascular pathogenesis. Processing speed is commonly impaired in cerebrovascular disease.

Methods

The data was obtained from the population based study “Good aging in Skåne” (GÅS), and included 905 individuals (mean age = 68 years). We investigated the impact of impaired kidney function at baseline on the development of dementia, MCI, and impairment in specific cognitive domains at follow up 6 years later, using logistic regression models. Impaired kidney function was defined as GFR < 60 ml/min/1,73 m². GFR was estimated from creatinine and cystatin C, using the CKD-EPI formula. Function in the cognitive domains learning and memory, language, complex attention, executive function, perceptual-motor, as well as meta-memory, and global cognitive function, was assessed using a neuropsychological test battery consisting of 12 tests. We compared the test results from follow up, with the results obtained at baseline, using linear regression models in order to assess changes in performance in cognitive domains.

Results

At follow up, 14 and 158 participants had developed dementia and MCI, respectively. We did not find evidence that moderately impaired eGFR at baseline increased the odds of dementia or MCI. A decline in processing speed was associated with impaired kidney function.

Conclusions

The effect on processing speed could represent early vascular implications on cognition. Even at moderately impaired kidney function, overview of cardiovascular risk factors could potentially prevent further cognitive impairment.

Transition from mild cognitive impairment to normal cognition: Determining the predictors of reversion with multi-state Markov models

INTRODUCTION

The theoretical framework of the Alzheimer's disease continuum considers transition between stages in a unidirectional manner. Here we examine the rate of reversion from mild cognitive impairment (MCI) to normal cognition (NC) and explore a set of potential variables associated with this phenomenon.

METHODS

A total of 985 Spanish community-dwelling individuals aged 70 years and over at baseline were monitored for 5 years. During this time, 173 MCI and 36 dementia cases were identified. Multi-state Markov models were performed to characterize transitions between states through the dementia continuum.

RESULTS

The rate of reversion from MCI to NC was 11%. There were significant non-modifiable (age, socioeconomic status, or apolipoprotein E) and modifiable factors (cognitive training or absence of affective symptoms) associated with reversion.

DISCUSSION

Overall, our results highlight that the likelihood of progression from MCI to dementia is very similar to that of reversion from MCI to NC.

Validity Evidence for the Research Category, "Cognitively Unimpaired - Declining," as a Risk Marker for Mild Cognitive Impairment and Alzheimer's Disease

While clinically significant cognitive impairment is the key feature of the symptomatic stages of the Alzheimer's disease (AD) continuum, subtle cognitive decline is now known to occur years before a clinical diagnosis of mild cognitive impairment (MCI) or dementia due to AD is made. The primary aim of this study was to examine criterion validity evidence for an operational definition of "cognitively unimpaired-declining" (CU-D) in the Wisconsin Registry for Alzheimer's Prevention (WRAP), a longitudinal cohort study following cognition and risk factors from mid-life and on. Cognitive status was determined for each visit using a consensus review process that incorporated internal norms and published norms; a multi-disciplinary panel reviewed cases first to determine whether MCI or dementia was present, and subsequently whether CU-D was present, The CU-D group differed from CU-stable (CU-S) and MCI on concurrent measures of cognition, demonstrating concurrent validity. Participants who changed from CU-S to CU-D at the next study visit demonstrated greater declines than those who stayed CU-S. In addition, those who were CU-D were more likely to progress to MCI or dementia than those who were CU-S (predictive validity). In a subsample with positron emission tomography (PET) imaging, the CU-D group also differed from the CU-S and MCI/Dementia groups on measures of amyloid and tau burden, indicating that biomarker evidence of AD was elevated in those showing sub-clinical (CU-D) decline. Together, the results corroborate other studies showing that cognitive decline begins long before a dementia diagnosis and indicate that operational criteria can detect subclinical decline that may signal AD or other dementia risk.

Prevalence of Mild Cognitive Impairment in the Lothian Birth Cohort 1936

BACKGROUND

The Lothian Birth Cohort 1936 (LBC1936) is a highly phenotyped longitudinal study of cognitive and brain ageing. Given its substantial clinical importance, we derived an indicator of mild cognitive impairment (MCI) and amnestic and nonamnestic subtypes at 3 time points.

METHODS

MCI status was derived at 3 waves of the LBC1936 at ages 76 (n=567), 79 (n=441), and 82 years (n=341). A general MCI category was derived as well as amnestic MCI (aMCI) and nonamnestic MCI (naMCI). A comparison was made between MCI derivations using normative data from the LBC1936 cohort versus the general UK population.

RESULTS

MCI rates showed a proportional increase at each wave between 76 and 82 years from 15% to 18%. Rates of MCI subtypes also showed a proportional increase over time: aMCI 4% to 6%; naMCI 12% to 16%. Higher rates of MCI were found when using the LBC1936 normative data to derive MCI classification rather than UK-wide norms.

CONCLUSIONS

We found that MCI and aMCI rates in the LBC1936 were consistent with previous research. However, naMCI rates were higher than expected. Future LBC1936 research should assess the predictive factors associated with MCI prevalence to validate previous findings and identify novel risk factors.

European Academy of Neurology/European Alzheimer's Disease Consortium position statement on diagnostic disclosure, biomarker counseling, and management of patients with mild cognitive impairment

BACKGROUND AND PURPOSE

Careful counseling through the diagnostic process and adequate postdiagnostic support in patients with mild cognitive impairment (MCI) is important. Previous studies have indicated heterogeneity in practice and the need for guidance for clinicians.

METHODS

A joint European Academy of Neurology/European Alzheimer's Disease Consortium panel of dementia specialists was appointed. Through online meetings and emails, positions were developed regarding disclosing a syndrome diagnosis of MCI, pre- and postbiomarker sampling counseling, and postdiagnostic support.

RESULTS

Prior to diagnostic evaluation, motives and wishes of the patient should be sought. Diagnostic disclosure should be carried out by a dementia specialist taking the ethical principles of "the right to know" versus "the wish not to know" into account. Disclosure should be accompanied by written information and a follow-up plan. It should be made clear that MCI is not dementia. Prebiomarker counseling should always be carried out if biomarker sampling is considered and postbiomarker counseling if sampling is carried out. A dementia specialist knowledgeable about biomarkers should inform about pros and cons, including alternatives, to enable an autonomous and informed decision. Postbiomarker counseling will depend in part on the results of biomarkers. Follow-up should be considered for all patients with MCI and include brain-healthy advice and possibly treatment for specific underlying causes. Advice on advance directives may be relevant.

CONCLUSIONS

Guidance to clinicians on various aspects of the diagnostic process in patients with MCI is presented here as position statements. Further studies are needed to enable more evidence-based and standardized recommendations in the future.

Neuropsychological test validation of speech markers of cognitive impairment in the Framingham Cognitive Aging Cohort

AIM

Although clinicians primarily diagnose dementia based on a combination of metrics such as medical history and formal neuropsychological tests, recent work using linguistic analysis of narrative speech to identify dementia has shown promising results. We aim to build upon research by Thomas JA & Burkardt HA et al. (J Alzheimers Dis. 2020;76:905-22) and Alhanai et al. (arXiv:1710.07551v1. 2020) on the Framingham Heart Study (FHS) Cognitive Aging Cohort by 1) demonstrating the predictive capability of linguistic analysis in differentiating cognitively normal from cognitively impaired participants and 2) comparing the performance of the original linguistic features with the performance of expanded features.

METHODS

Data were derived from a subset of the FHS Cognitive Aging Cohort. We analyzed a sub-selection of 98 participants, which provided 127 unique audio files and clinical observations (n = 127, female = 47%, cognitively impaired = 43%). We built on previous work which extracted original linguistic features from transcribed audio files by extracting expanded features. We used both feature sets to train logistic regression classifiers to distinguish cognitively normal from cognitively impaired participants and compared the predictive power of the original and expanded linguistic feature sets, and participants' Mini-Mental State Examination (MMSE) scores.

RESULTS

Based on the area under the receiver-operator characteristic curve (AUC) of the models, both the original (AUC = 0.882) and expanded (AUC = 0.883) feature sets outperformed MMSE (AUC = 0.870) in classifying cognitively impaired and cognitively normal participants. Although the original and expanded feature sets had similar AUC, the expanded feature set showed better positive and negative predictive value [expanded: positive predictive value (PPV) = 0.738, negative predictive value (NPV) = 0.889; original: PPV = 0.701, NPV = 0.869].

CONCLUSIONS

Linguistic analysis has been shown to be a potentially powerful tool for clinical use in classifying cognitive impairment. This study expands the work of several others, but further studies into the plausibility of speech analysis in clinical use are vital to ensure the validity of speech analysis for clinical classification of cognitive impairment.

Validation of Indian Council of Medical Research Neurocognitive Tool Box in Diagnosis of Mild Cognitive Impairment in India: Lessons from a Harmonization Process in a Linguistically Diverse Society

BACKGROUND/AIMS

In a linguistically diverse country such as India, challenges remain with regard to diagnosis of early cognitive decline among the elderly, with no prior attempts made to simultaneously validate a comprehensive battery of tests across domains in multiple languages. This study aimed to determine the utility of the Indian Council of Medical Research-Neurocognitive Tool Box (ICMR-NCTB) in the diagnosis of mild cognitive impairment (MCI) and its vascular subtype (VaMCI) in 5 Indian languages.

METHODS

Literate subjects from 5 centers across the country were recruited using a uniform process, and all subjects were classified based on clinical evaluations and a gold standard test protocol into normal cognition, MCI, and VaMCI. Following adaptation and harmonization of the ICMR-NCTB across 5 different Indian languages into a composite Z score, its test performance against standards, including sensitivity and specificity of the instrument as well as of its subcomponents in diagnosis of MCI, was evaluated in age and education unmatched and matched groups.

RESULTS

Variability in sensitivity-specificity estimates was noted between languages when a total of 991 controls and 205 patients with MCI (157 MCI and 48 VaMCI) were compared due to a significant impact of age, education, and language. Data from a total of 506 controls, 144 patients with MCI, and 46 patients with VaMCI who were age- and education-matched were compared. Post hoc analysis after correction for multiple comparisons revealed better performance in controls relative to all-cause MCI. An optimum composite Z-score of -0.541 achieved a sensitivity of 81.1% and a specificity of 88.8% for diagnosis of all-cause MCI, with a high specificity for diagnosis of VaMCI. Using combinations of multiple-domain 2 test subcomponents retained a sensitivity and specificity of >80% for diagnosis of MCI.

CONCLUSIONS

The ICMR-NCTB is a "first of its kind" approach at harmonizing neuropsychological tests across 5 Indian languages for the diagnosis of MCI due to vascular and other etiologies. Utilizing multiple-domain subcomponents also retains the validity of this instrument, making it a valuable tool in MCI research in multilingual settings.

Cerebrovascular and Neurodegenerative Pathologies in Long-Term Stable Mild Cognitive Impairment

BACKGROUND

Mild cognitive impairment (MCI) is considered by some to be a prodromal phase of a progressive disease (i.e., neurodegeneration) resulting in dementia; however, a substantial portion of individuals (ranging from 5-30%) remain cognitively stable over the long term (sMCI). The etiology of sMCI is unclear but may be linked to cerebrovascular disease (CVD), as evidence from longitudinal studies suggest a significant proportion of individuals with vasculopathy remain stable over time.

OBJECTIVE

To quantify the presence of neurodegenerative and vascular pathologies in individuals with long-term (>5-year) sMCI, in a preliminary test of the hypothesis that CVD may be a contributor to non-degenerative cognitive impairment. We expect frequent vasculopathy at autopsy in sMCI relative to neurodegenerative disease, and relative to individuals who convert to dementia.

METHODS

In this retrospective study, using data from the National Alzheimer's Coordinating Center, individuals with sMCI (n = 28) were compared to those with MCI who declined over a 5 to 9-year period (dMCI; n = 139) on measures of neurodegenerative pathology (i.e., Aβ plaques, neurofibrillary tangles, TDP-43, and cerebral amyloid angiopathy) and CVD (infarcts, lacunes, microinfarcts, hemorrhages, and microbleeds).

RESULTS

Alzheimer's disease pathology (Aβ plaques, neurofibrillary tangles, and cerebral amyloid angiopathy) was significantly higher in the dMCI group than the sMCI group. Microinfarcts were the only vasculopathy associated with group membership; these were more frequent in sMCI.

CONCLUSION

The most frequent neuropathology in this sample of long-term sMCI was microinfarcts, tentatively suggesting that silent small vessel disease may characterize non-worsening cognitive impairment.

Predictors of Mild Cognitive Impairment Stability, Progression, or Reversion in the Lothian Birth Cohort 1936

BACKGROUND

Mild cognitive impairment (MCI) describes a borderland between healthy cognition and dementia. Progression to and reversion from MCI is relatively common but more research is required to understand the factors affecting this fluidity and improve clinical care interventions.

OBJECTIVE

We explore these transitions in MCI status and their predictive factors over a six-year period in a highly-phenotyped longitudinal study, the Lothian Birth Cohort 1936.

METHODS

MCI status was derived in the LBC1936 at ages 76 (n = 567) and 82 years (n = 341) using NIA-AA diagnostic guidelines. Progressions and reversions between healthy cognition and MCI over the follow-up period were assessed. Multinomial logistic regression assessed the effect of various predictors on the likelihood of progressing, reverting, or maintaining cognitive status.

RESULTS

Of the 292 participants who completed both time points, 41 (14%) participants had MCI at T1 and 56 (19%) at T2. Over the follow-up period, 74%remained cognitively healthy, 12%transitioned to MCI, 7%reverted to healthy cognition, and 7%maintained their baseline MCI status. Findings indicated that membership of these transition groups was affected by age, cardiovascular disease, and number of depressive symptoms.

CONCLUSION

Findings that higher baseline depressive symptoms increase the likelihood of reverting from MCI to healthy cognition indicate that there may be an important role for the treatment of depression for those with MCI. However, further research is required to identify prevention strategies for those at high risk of MCI and inform effective interventions that increase the likelihood of reversion to, and maintenance of healthy cognition.

Promising outcome measures of early Alzheimer's dementia in adults with Down syndrome

INTRODUCTION

Adults with Down syndrome (DS) are at high risk for developing Alzheimer's disease (AD) and its associated dementia, warranting the development of strategies to improve early detection when prevention is possible.

METHODS

Using a broad battery of neuropsychological assessments, informant interviews, and clinical record review, we evaluated the psychometrics of measures in a large sample of 561 adults with DS. We tracked longitudinal stability or decline in functioning in a subsample of 269 participants over a period of 3 years, all initially without indications of clinically significant aging-related decline.

RESULTS

Results identified an array of objective measures that demonstrated sensitivity in distinguishing individuals with incident "mild cognitive impairment" (MCI-DS) as well as subsequent declines occurring with incident dementia.

DISCUSSION

Several instruments showed clear promise for use as outcome measures for future clinical trials and for informing diagnosis of individuals suspected of experiencing early signs and symptoms of a progressive dementia process.