scholarly journals Role of Executive Functions in the Conversion from Mild Cognitive Impairment to Dementia

2020 ◽  
Vol 77 (2) ◽  
pp. 641-653
Author(s):  
Almudena Junquera ◽  
Estefanía García-Zamora ◽  
Javier Olazarán ◽  
Mario A. Parra ◽  
Sara Fernández-Guinea

Background: Recent research pointed to executive dysfunction as a potential early predictor of the progression of mild cognitive impairment (MCI) to dementia in Alzheimer’s clinical syndrome (ACS). Such cognitive impairments account for functional impairments in instrumental activities of daily living (IADL). Objective: The present study analyzes the contributions of executive functions to predict MCI–dementia progression in ACS. Methods: We assessed 145 participants, 51 cognitively unimpaired and 94 MCI. The latter were divided using the traditional, memory-based MCI classification (single domain amnestic, multidomain amnestic, and non-amnestic). Eight tests assessing executive functions were administered at baseline and at 1-year follow-up, together with cognitive screening tools and IADL measures. MCI patients were reclassified based on the outcomes from a K-mean cluster analysis which identified three groups. A simple lineal regression model was used to examine whether the classification based on executive functioning could more accurately predict progression to dementia a year later. Results: Clusters based on executive function deficits explained a significant proportion of the variance linked to MCI–dementia conversion, even after controlling for the severity of MCI at baseline (F(1, 68) = 116.25, p = 0.000, R2 = 0.63). Classical memory-based MCI classification failed to predict such a conversion (F(1, 68) = 5.09, p = 0.955, R2 = 0.07). Switching, categories generation, and planning were the executive functions that best distinguished between MCI converters and stable. Conclusion: MCI with a dysexecutive phenotype significantly predicts conversion to dementia in ACS a year later. Switching abilities and verbal fluency (categories) must be evaluated in MCI patients to assess risk of future dementia.

Author(s):  
Tarik Qassem ◽  
Mohamed S. Khater ◽  
Tamer Emara ◽  
Doha Rasheedy ◽  
Heba M. Tawfik ◽  
...  

<b><i>Background and Aims:</i></b> Mild cognitive impairment (MCI) represents an important point on the pathway to developing dementia and a target for early detection and intervention. There is a shortage of validated cognitive screening tools in Arabic to diagnose MCI. The aim of this study was to validate Addenbrooke’s Cognitive Examination-III (ACE-III) (Egyptian-Arabic version) in a sample of patients with MCI, to provide cut-off scores in Egyptian-Arabic speakers. <b><i>Methods:</i></b> A total of 24 patients with MCI and 54 controls were included in the study and were administered the Egyptian-Arabic version of the ACE-III. <b><i>Results:</i></b> There was a statistically significant difference (<i>p</i> &#x3c; 0.001) in the total ACE-III score between MCI patients (mean 75.83, standard deviation (SD) 8.1) and controls (mean 86.26, SD 6.74). There was also a statistically significant difference between MCI patients and controls in the memory, fluency, and visuospatial sub-scores of the ACE-III (<i>p</i> &#x3c; 0.05) but not in attention and language sub-scores. Using a receiver operator characteristic curve, the optimal cut-off score for diagnosing MCI on the ACE-III total score was 81, with 75% sensitivity, 82% specificity, and 80% accuracy. <b><i>Conclusions:</i></b> The results of this study provide objective validation of the Egyptian-Arabic version of the ACE-III as a screening tool for MCI, with good sensitivity, specificity, and accuracy that are comparable to other translated versions of the ACE-III in MCI.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nimantha Karunathilaka ◽  
Sarath Rathnayake

Abstract Objective Recent evidence demonstrates that obesity is associated with developing cognitive impairment. However, evidence related to the assessment of mild cognitive impairment (MCI) in people with obesity is limited. Therefore, this systematic review aimed to examine evidence concerning the screening of MCI in people with obesity from the general population. Method We conducted a systematic search of CINHAL, EMBASE, MEDLINE, PsycINFO and PubMed electronic databases for observational studies to assess MCI in people with obesity from the general population. PRISMA guideline was followed. The articles published from January 2011 to July 2021 were included. Results Database search found 3104 sources. After the screening process, two articles from China and Egypt were included. The main age groups assessed were middle-aged adulthood and older adulthood. There were no studies undertaken in young adults or across the life span. Obesity was assessed by body mass index. MCI was assessed by cognitive screening tools; Mini-mental State Examination and Addenbrooke’s Cognitive Examination. The prevalence of MCI in people with obesity was 18.5 % and 42.9 % in Chinese and Egyptian studies, respectively. Only one study supported a positive association between MCI and obesity. Conclusions Limited studies were found on screening MCI in people with obesity in the general population. The available evidence was not adequate to explain the overall prevalence, possible associations, and the best tool for assessing MCI in people with obesity. Expanding screening studies for MCI in people with obesity in the general population is essential.


2021 ◽  
Vol 5 (1) ◽  
pp. 207-211
Author(s):  
Marwan Sabbagh ◽  
Justin Miller ◽  
Stephen Jones ◽  
Aaron Ritter ◽  
Jiong Shi ◽  
...  

Background: Informant-based measures are effective screening tools for cognitive impairment. The Alzheimer’s Questionnaire (AQ) is a subjective, informant-based measure that detects amnestic mild cognitive impairment (aMCI) and Alzheimer’s disease (AD) with high sensitivity and specificity and has been shown to predict amyloid burden. Objective: To determine whether informant-based report of cognitive decline correlates with hippocampal volume changes in MCI and AD. Methods: Retrospective chart review of 139 clinically referred patients with clinical diagnoses of aMCI or mild dementia due to AD was conducted. Diagnostic status (clinical diagnosis made by a neurologist), NeuroQuant measured MRI brain with percentile rank hippocampal volume, Montreal Cognitive Assessment (MoCA) total, AQ-Total score, and demographic variables were extracted from medical records. Spearman correlation was used to assess the relationship between hippocampal volume and AQ-Total. The AQ was used to assign diagnostic status. Thus, the relationship between the AQ and diagnostic status was excluded. Results: The sample include 88 female and 51 male participants. The mean age was 74.37±9.45, mean MOCA was 22.65±4.18, mean education was 14.80±3.35, and mean AQ score was 10.54±5.22. Hippocampal volume and the AQ correlation was r = –0.33 [95%CI –0.47 to –0.17], p < 0.0001. Conclusion: In a mixed-clinical sample of patients presenting to an outpatient memory disorders center, higher endorseme-nts of functional impairments by caregivers were significantly associated with smaller hippocampal volumes. When used in conjunction with other available measures, these findings further support the role of the AQ in clinical decision-making and demonstrate an additional relationship between clinical measures and volumetric MRI.


Author(s):  
Ilaria Corbo ◽  
Maria Casagrande

Mild Cognitive Impairment (MCI) is a clinical syndrome characterized by a moderate decline in one or more cognitive functions with a preserved autonomy in daily life activities [1]. MCI exhibits cognitive, behavioral, psychological symptoms [2]. The executive functions (EFs) are a set of key functions for everyday life and physical and mental health; and allow adapting the behavior to external changes [3-5]. Higher-level executive functions develop from basic EFs (inhibition, working memory, attentional control, and cognitive flexibility). They are planning, reasoning, problem- solving, and fluid intelligence (Gf) [3]. This systematic review investigates the relationship between higher-level executive functions and healthy and pathological aging, assuming the role of executive functions deficits as a predictor of cognitive decline. The systematic review was conducted according to the PRISMA Statement [6-7]. A total of 73 studies were identified. The results indicate that 65.8% of the studies confirm significant EFs alterations in MCI (100% problem solving, 71.4% fluid intelligence, 56.8% planning, 50% reasoning). These results seem to highlight a strong prevalence of higher-level executive functions deficits in MCI elderly than in healthy elderly.


2016 ◽  
Vol 42 (1-2) ◽  
pp. 1-9 ◽  
Author(s):  
Frank G. van Rooij ◽  
Roy P.C. Kessels ◽  
Edo Richard ◽  
Frank-Erik De Leeuw ◽  
Ewoud J. van Dijk

Background: Although by definition a transient ischemic attack (TIA) lasts less than 24 h, many patients experience cognitive complaints beyond focal symptom resolution. However, their prevalence, causes and profile are unclear. We therefore performed a systematic review on cognitive impairment after TIA. Summary: Medline and Embase were searched for relevant studies. Risk of bias was assessed, and data synthesis was performed according to the severity of cognitive impairment. Thirteen studies were included, with considerable heterogeneity concerning methods and timing of cognitive testing. Confounding, detection bias and attrition were the main causes of a high risk of bias in several studies. The prevalence of post-TIA mild cognitive impairment ranged from 29 to 68%. Severe cognitive impairment was found in 8-22% of patients. Studies using a cognitive screening instrument and those performed shortly after TIA or several years later, reported the highest frequencies of impairment. Patients evaluated with a screening tool were substantially older than those who underwent a full neuropsychological assessment (weighted mean age difference 10.9 years). Based on limited data, the post-TIA cognitive profile showed prominent executive function deficits. Insufficient data refrained us from drawing conclusions on causality. The few studies that reported neuroimaging results found a minor correlation with cognitive impairment. Key Messages: Mild cognitive impairment is present in more than a third of the TIA patients and has a profile comparable with vascular cognitive impairment. Reported rates of post-TIA cognitive impairment are highly variable and higher frequencies are found with cognitive screening tools. Considerable heterogeneity and insufficient data limit further conclusions about potential causative factors.


2021 ◽  
Vol 55 (2) ◽  
pp. 79-91
Author(s):  
Yan Deng ◽  
Siqi Zhao ◽  
Guangwen Cheng ◽  
Jiajia Yang ◽  
Benchao Li ◽  
...  

<b><i>Background:</i></b> Mild cognitive impairment (MCI) induced the majority number of dementia patients. The prevalence of MCI in China varied across studies with different screening tools and diagnostic criteria. <b><i>Objective:</i></b> A systematic review and meta-analysis was conducted to estimate the pooled MCI prevalence among the population aged 55 years and older in China. <b><i>Methods:</i></b> PubMed, EMBASE, CNKI, Wanfang, CQVIP, and CBMdisc were searched for studies on prevalence of MCI among Chinese elderly between January 1, 1980, and February 10, 2020. The quality assessment was conducted via external validity, internal validity, and informativity, the pooled prevalence was calculated through the random-effect model, and the homogeneity was evaluated by Cochran’s <i>Q</i> test and <i>I</i><sup>2</sup>. <b><i>Results:</i></b> Fifty-three studies with 123,766 subjects were included. The pooled prevalence of MCI among Chinese elderly was 15.4% (95% CI: 13.5–17.4%). Subgroup analyses indicated that the prevalence calculated with different screening tools was 20.2% (95% CI: 15.1–25.9%) for Montreal Cognitive Assessment (MoCA) and 13.0% (95% CI: 10.7–15.5%) for Mini-Mental State Examination (MMSE). According to different diagnostic criteria, the prevalence was 14.8% (95% CI: 12.2–17.6%) for Petersen criteria, 15.0% (95% CI: 12.7–17.5%) for DSM-IV, and 21.2% (95% CI: 17.5–25.2%) for Chinese Expert Consensus on Cognitive Impairment (CECCI). Besides, women, older adults, illiterate people, rural residents, and those who lived with unhealthy lifestyles and morbidity showed higher prevalence. <b><i>Conclusions:</i></b> The prevalence of MCI in China was 15.4%, which varied by demographics, lifestyles, morbidity, screening tools, and diagnostic criteria. In further studies, screening tools and diagnosis criteria should be considered when estimating MCI prevalence.


2021 ◽  
pp. 1-15
Author(s):  
Manu J. Sharma ◽  
Brandy L. Callahan

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.


Neurocase ◽  
2012 ◽  
Vol 18 (4) ◽  
pp. 336-351 ◽  
Author(s):  
Samrah Ahmed ◽  
Celeste de Jager ◽  
Gordon Wilcock

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