Mild Cognitive Impairment: A Brief Review and Suggested Clinical Algorithm

Are subjective language complaints in memory clinic patients informative?

To diagnose mild cognitive impairment, it is crucial to understand whether subjective cognitive complaints reflect objective cognitive deficits. This question has mostly been investigated in the memory domain, with mixed results. Our study was one of the first to address it for language. Participants were 55-to-93-year-old memory clinic patients (n = 163). They filled in a questionnaire about subjective language and memory complaints and performed two language tasks (naming-by-definition and sentence comprehension). Greater language complaints were associated with two language measures, thus showing a moderate value in predicting language performance. Greater relative severity of language versus memory complaints was a better predictor, associated with three language performance measures. Surprisingly, greater memory complaints were associated with better naming, probably due to anosognosia in further disease progression or personality-related factors. Our findings highlight the importance of relative complaint severity across domains and, clinically, call for developing self-assessment questionnaires asking specific questions about multiple cognitive functions.

Human Leukocyte Antigen and microRNAs as Key Orchestrators of Mild Cognitive Impairment and Alzheimer's Disease: A Systematic Review

The expression of inflamma-miRs and human leukocyte antigen (HLA) haplotypes could indicate mild cognitive impairment (MCI) and Alzheimer's disease (AD). We used international databases to conduct a systematic review of studies on HLA variants and a meta-analysis of research on microRNAs (miRNAs). We aimed to analyze the discriminative value of HLA variants and miRNAs in MCI, AD and controls to evaluate the protective or causative effect of HLA in cognitive decline, establish the role of miRNAs as biomarkers for the early detection of AD, and find a possible link between miRNAs and HLA. Statistical analysis was conducted using Comprehensive Meta-analysis software, version 2.2.050 (Biostat Inc., Englewood, NJ, USA). The effect sizes were estimated by the logarithm base 2 of the fold change. The systematic review revealed that some HLA variants, such as HLA-B*4402, HLA-A*33:01, HLA-A*33:01, HLA-DPB1, HLA-DR15, HLA-DQB1*03:03, HLA-DQB1*06:01, HLA-DQB1*03:01, SNPs on HLA-DRB1/DQB1, and HLA-DQA1, predisposed to cognitive decline before the occurrence of AD, while HLA-A1*01, HLA-DRB1∗13:02, HLA-DRB1*04:04, and HLA-DRB1*04:01 demonstrated a protective role. The meta-analysis identified let-7 and miR-15/16 as biomarkers for the early detection of AD. The association between these two miRNA families and the HLA variants that predispose to AD could be used for the early screening and prevention of MCI.

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.

Cognitive and Neuroimaging Profiles of Older Adults With Attention Deficit/Hyperactivity Disorder Presenting to a Memory Clinic

OBJECTIVE

Some features of attention-deficit/hyperactivity disorder (ADHD) may resemble those of mild cognitive impairment (MCI) in older adults, contributing to diagnostic uncertainty in individuals seeking assessment in memory clinics. We systematically compared cognition and brain structure in ADHD and MCI to clarify the extent of overlap and identify potential features unique to each.

METHOD

Older adults from a Cognitive Neurology clinic (40 ADHD, 29 MCI, 37 controls) underwent neuropsychological assessment. A subsample (n = 80) underwent structural neuroimaging.

RESULTS

Memory was impaired in both patient groups, but reflected a storage deficit in MCI (supported by relatively smaller hippocampi) and an encoding deficit in ADHD (supported by frontal lobe thinning). Both groups displayed normal executive functioning. Semantic retrieval was uniquely impaired in MCI.

CONCLUSION

Although ADHD has been proposed as a dementia risk factor or prodrome, we propose it is rather a pathophysiologically-unique phenotypic mimic acting via overlap in memory and executive performance.

Exploring the Association between Multimorbidity and Cognitive Impairment in Older Adults Living in the Community: A Review of the Literature

Two-thirds of older adults have multimorbidity (MM), or co-occurrence of two or more medical conditions. Mild cognitive impairment (CI) is found in almost 20% of older adults and can lead to further cognitive decline and increased mortality. Older adults with MM are the primary users of home health care services and are at high risk for CI development; however, there is no validated cognitive screening tool used to assess the level of CI in home health users. Given the prevalence of MM and CI in the home health setting, we conducted a review of the literature to understand this association. Due to the absence of literature on CI in home health users, the review focused on the association of MM and CI in community-dwelling older adults. Search terms included home health, older adults, cognitive impairment, and multimorbidity and were applied to the databases PubMed, CINAHL, and PsychInfo leading to eight studies eligible for review. Results show CI is associated with MM in older adults of increasing age, among minorities, and in older adults with lower levels of education. Heart disease was the most prevalent disease associated with increased CI. Sleep disorders, hypertension, arthritis, and hyperlipidemia were also significantly associated with increased CI. The presence of MM and CI was associated with increased risk for death among older adults. Further research and attention are needed regarding the use and development of a validated cognitive assessment tool for home health users to decrease adverse outcomes in the older adult population.

The Persian Version of the Quick Mild Cognitive Impairment Screen (Qmci-Pr): Psychometric Properties among Middle-Aged and Older Iranian Adults

Brief cognitive screening instruments are used to identify patients presenting with cognitive symptoms that warrant further assessment. This study aimed to evaluate the reliability and validity of the Persian version of the Quick Mild Cognitive Impairment (Qmci-Pr) among middle-aged and older Iranian adults. Consecutive patients aged ≥55 years and caregivers attending with them as normal controls (NCs) were recruited from geriatric outpatient clinics and a hospital in Tehran, Iran. All patients completed the Qmci-Pr before completing an independent detailed neuropsychological assessment and staging using the Clinical Dementia Rating (CDR) Scale. NCs underwent the same assessment. In all, 92 participants with a median age of 70 years (±13) were available. Of these, 20 participants were NCs, 24 had subjective memory complaints (SMC), 24 had mild cognitive impairment (MCI), and 24 had Alzheimer's disease (AD). The Qmci-Pr had good accuracy in differentiating SMC and NC from MCI (area under the curve (AUC): 0.80 (0.69-0.91)) and in identifying cognitive impairment (MCI and mild AD) (AUC: 0.87 (0.80-0.95)) with a sensitivity of 88% and specificity of 80%, at an optimal cut-off of <53/100. The Qmci-Pr is an accurate short cognitive screening impairment for separating NC and patients with SMC from MCI and identifying cognitive impairment. Further research with larger samples and comparison with other widely used instruments such as the Montreal Cognitive Assessment is needed. Given its established brevity, the Qmci-Pr is a useful screen for Iranian adults across the spectrum of cognitive decline.

Comparison of Urinary Alzheimer-Associated Neural Thread Protein (AD7c-NTP) Levels Between Patients With Amnestic and Nonamnestic Mild Cognitive Impairment

Urinary Alzheimer-associated neural thread protein (AD7c-NTP) is a potential biomarker of Alzheimer disease (AD) or mild cognitive impairment (MCI). It is still unclear whether the urinary levels of AD7c-NTP are different between patients with amnestic MCI (aMCI) and nonamnestic MCI (naMCI). The present study aimed to explore the differences in urinary levels of AD7c-NTP between patients with aMCI and naMCI. Forty-six patients with MCI were divided into aMCI group (n = 23) and naMCI group (n = 23). The mean level of urinary AD7c-NTP in the aMCI group (32.75 ± 10.0 µg/mL) was significantly higher than that in the naMCI group (25.34 ± 9.0 µg/mL; P = .011). As far as we know, the present study is the first to show that individuals with aMCI have higher levels of urinary AD7c-NTP than those with naMCI, suggesting that urinary AD7c-NTP may be a potential biomarker to help identify patients with aMCI and naMCI.

Comparison between FCSRT and LASSI-L to Detect Early Stage Alzheimer's Disease

BACKGROUND

The Free and Cued Selective Reminding Test (FCSRT) is the most accurate test for the diagnosis of prodromal Alzheimer's disease (AD). Recently, a novel cognitive test, the Loewenstein-Acevedo Scale for Semantic Interference and Learning (LASSI-L), has been developed in order to provide an early diagnosis.

OBJECTIVE

To compare the diagnostic accuracy of the FCSRT and the LASSI-L for the diagnosis of AD in its preclinical and prodromal stages using 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) as a reference.

METHODS

Fifty patients consulting for subjective memory complaints without functional impairment and at risk for AD were enrolled and evaluated using FCSRT, LASSI-L, and FDG-PET. Participants were evaluated using a comprehensive neurological and neuropsychological protocol and were assessed with the FCSRT and LASSI-L. FDG-PET was acquired concomitantly and used for classification of patients as AD or non-AD according to brain metabolism using both visual and semi-quantitative methods.

RESULTS

LASSI-L scores allowed a better classification of patients as AD/non-AD in comparison to FCSRT. Logistic regression analysis showed delayed recall and failure to recovery from proactive semantic interference from LASSI-L as independent statistically significant predictors, obtaining an area under the curve of 0.894. This area under the curve provided a better discrimination than the best FCSRT score (total delayed recall, area under the curve 0.708, p = 0.029).

CONCLUSIONS

The LASSI-L, a cognitive stress test, was superior to FCSRT in the prediction of AD features on FDG-PET. This emphasizes the possibility to advance toward an earlier diagnosis of AD from a clinical perspective.

The Link between Potassium and Mild Cognitive Impairment in Mexican-Americans

Background

Recent evidence suggests that increasing dietary intake of minerals reduces the risk of dementia. This study aimed to examine the relationship between potassium and diagnosis of mild cognitive impairment (MCI) in a sample of older Mexican-Americans from rural and urban populations.

Methods

The sample was formed of a total of 139 participants with MCI and 371 normal controls from two independent cohorts: a rural cohort (Facing Rural Obstacles to Healthcare Now through Intervention, Education and Research [Project FRONTIER]) and an urban cohort (the Health and Aging Brain among Latino Elders [HABLE] study). Serum electrolytes examined were sodium and potassium. Age and education were entered in the model as covariates.

Results

Across both cohorts, the Project FRONTIER (OR = 3.1; p = 0.01) and the HABLE Project (OR = 2.0; p = 0.04), the results indicated that serum potassium levels significantly increased the risk of diagnosis of MCI.

Conclusion

Our finding suggested a link between serum potassium levels and a diagnosis of MCI in Mexican-Americans. The results of this study support a previous research which has suggested that the risk factors for MCI may vary by ethnicity.

Cognitive rehabilitation in patients with nonamnestic mild cognitive impairment

Background:

The nonamnesic type of mild cognitive impairment (na-MCI) is predementia state with subtle decline incognitive domains except memory. Although cognitive rehabilitation (CR) has been investigated in amnesic type of MCI, we could not find any trial that rehabilitated na-MCI exclusively. We studied the effectiveness of CR on na-MCI.

Materials and Methods:

This study was a blinded, randomized clinical trial. Individuals with age of 60 years or more, complete self-directedness and diagnosis of na-MCI, based on Neuropsychiatry Unit Cognitive assessment tool, were selected. The 51 patients were randomly assigned into three groups: CR, lifestyle (LS) modification, and the control group (CG). Neuropsychological tests for executive functioning were assessed at the baseline, after the interventions, and 6 months later.

Results:

The mean score of the “design fluency” test increased significantly in CR, compared to LS and CG (P = 0.007). In “five-point” test, mean score increased significantly in CR (P = 0.03). There was higher mean score of Behavioral Rating Inventory of Executive Function for adults in CR (P = 0.01).

Conclusion:

Consideration of the MCI subtypes allows us to target specific cognitive domains, such as information processing, for better CR outcome. CR may result in better performance of executive functioning of daily living.

Validation of the Montreal Cognitive Assessment (MoCA) in Spanish as a screening tool for mild cognitive impairment and mild dementia in patients over 65 years old in Bogotá, Colombia

OBJECTIVE

The Montreal Cognitive Assessment (MoCA) was developed as a simple screening tool for cognitive impairment. This study is the first validation in Latin America of the MoCA in Spanish (MoCA-S), which was developed in Colombia (South America).

METHODS

Aiming to perform the first validation of the MoCA-S, we developed a study of concordance by conformity to assess the MoCA-S compared with diagnostic consensus by interdisciplinary assessment in the Memory Clinic (the best diagnostic method available) and to evaluate the psychometric properties of the MoCA-S. A total of 193 subjects were evaluated, 109 of whom were patients, including 26 who met the mild cognitive impairment (MCI) clinical criteria, based on neuropsychological testing, and 83 who had mild dementia (MD). The remaining 84 participants were healthy subjects from the community.

RESULTS

The psychometric evaluation of the MoCA-S was appropriate. Using a cutoff score of ≥ 23, the MoCA had sensitivities of 76.0% to detect MCI and 92.7% to detect MD and a specificity of 79.8%. The percentage of patients clearly labeled by the MoCA-S was 85%.

CONCLUSION

The MoCA-S is a valid screening tool and is useful for identifying MCI and MD in Colombia. The MoCA-S is valid and adequate for application in Colombia with good internal consistency, inter-observer reliability, and content validity. However, the average educational level was high in this study; thus, caution should be exercised when extrapolating these results to individuals with lower educational levels.

Cognitive profiles in patients with multi-infarct dementia: an omani study

Background

Studies on neurocognitive impairment among patients presenting with multi-infarct dementia (MID) have received little attention from non-Western societies, and the Arab world is no exception. To our knowledge, this is the first study to characterize neurocognitive, affective and vegetative functioning in patients with MID in Oman.

Methods

In this study, we recruited 20 Omani patients presenting with MID and age- and gender-matched controls at the outpatient clinic of the Department of Behavioral Medicine, Sultan Qaboos University Hospital, Sultan Qaboos University, Muscat, Oman. In addition to the collection of clinical and demographic information, various cognitive batteries were administered to the consenting participants, including those indexing nonverbal reasoning abilities, working memory (attention, concentration and recall) and executive functioning. Questionnaires that elicit the affective range and the quality of sleep were also administered.

Results

Compared with the matched healthy subjects, the patients diagnosed with MID significantly differed in the presently operationalized indices of visuospatial function, semantic memory and affective and vegetative functioning. In contrast, episodic memory and some attentional capacities were not significantly different compared with the control subjects.

Conclusions

The present study was explorative and clinically designed to describe neurocognitive functioning in patients with MID seeking consultation at a tertiary care center in Oman. Our data are necessary for planning and setting up community services and health care programs for demented patients in a society where dementia is a growing silent epidemic.