Mild cognitive impairment: historical development and summary of research

Effects of a dual intervention (motor and virtual reality-based cognitive) on cognition in patients with mild cognitive impairment: a single-blind, randomized controlled trial

BACKGROUND

The increase in cases of mild cognitive impairment (MCI) underlines the urgency of finding effective methods to slow its progression. Given the limited effectiveness of current pharmacological options to prevent or treat the early stages of this deterioration, non-pharmacological alternatives are especially relevant.

OBJECTIVE

To assess the effectiveness of a cognitive-motor intervention based on immersive virtual reality (VR) that simulates an activity of daily living (ADL) on cognitive functions and its impact on depression and the ability to perform such activities in patients with MCI.

METHODS

Thirty-four older adults (men, women) with MCI were randomized to the experimental group (n = 17; 75.41 ± 5.76) or control (n = 17; 77.35 ± 6.75) group. Both groups received motor training, through aerobic, balance and resistance activities in group. Subsequently, the experimental group received cognitive training based on VR, while the control group received traditional cognitive training. Cognitive functions, depression, and the ability to perform activities of daily living (ADLs) were assessed using the Spanish versions of the Montreal Cognitive Assessment (MoCA-S), the Short Geriatric Depression Scale (SGDS-S), and the of Instrumental Activities of Daily Living (IADL-S) before and after 6-week intervention (a total of twelve 40-minutes sessions).

RESULTS

Between groups comparison did not reveal significant differences in either cognitive function or geriatric depression. The intragroup effect of cognitive function and geriatric depression was significant in both groups (p < 0.001), with large effect sizes. There was no statistically significant improvement in any of the groups when evaluating their performance in ADLs (control, p = 0.28; experimental, p = 0.46) as expected. The completion rate in the experimental group was higher (82.35%) compared to the control group (70.59%). Likewise, participants in the experimental group reached a higher level of difficulty in the application and needed less time to complete the task at each level.

CONCLUSIONS

The application of a dual intervention, through motor training prior to a cognitive task based on Immersive VR was shown to be a beneficial non-pharmacological strategy to improve cognitive functions and reduce depression in patients with MCI. Similarly, the control group benefited from such dual intervention with statistically significant improvements.

TRIAL REGISTRATION

ClinicalTrials.gov NCT06313931; https://clinicaltrials.gov/study/NCT06313931 .

An Examination of the Motives for Attributing and Interpreting Deception in People with Amnestic Mild Cognitive Impairment

The aim of the present study was to examine how a person with amnestic mild cognitive impairment perceives the phenomenon of deception. Amnestic mild cognitive impairment (aMCI) usually represents the prodromal phase of Alzheimer's disease (AD), with patients showing memory impairment but with normal activities of daily living. It was expected that aMCI patients would face difficulties in the attribution and interpretation of deceptive behavior due to deficits regarding their diagnosis. The main sample of the study consisted of 76 older adults who were patients of a daycare center diagnosed with aMCI. A sample of 55 highly educated young adults was also examined in the same experiment to qualitatively compare their performance with that of aMCI patients. Participants were assigned a scenario where a hypothetical partner (either a friend or a stranger) was engaged in a task in which the partner could lie to boost their earnings at the expense of the participant. The results showed that aMCI patients, even if they understood that something was going wrong, did not invest in interpretations of potential deception and tended to avoid searching for confirmative information related to the hypothetical lie of their partner compared to highly educated young adults. It seems that aMCI patients become somehow "innocent", and this is discussed in terms of cognitive impairment and/or socioemotional selectivity.

Sex-dependent differences in animal cognition

The differences in cognitive processes driven by biological sex are the issues that have gotten growing attention recently. Considering the increasing population suffering from various cognitive impairments and the development of therapeutic strategies, it is essential that we recognize the mechanisms responsible for discrepancies observed in male and female learning and memory functions. In this review, we discuss recent reports from preclinical studies on rodents regarding selected cognitive domains to explore the state of knowledge on sex-dependent differences and point to challenges encountered during such research. We focus on spatial, recognition, and emotional memory, as well as on executive functions, such as attention, cognitive flexibility, and working memory. This review will help to acknowledge sex-related differences in cognition and indicate some fields that lack sufficient data.

Face-to-face vs. Telerehabilitation language and cognitive training in patients with multi-domain amnestic mild cognitive impairment

The recent coronavirus emergency raised the question of whether telerehabilitation could be as effective as conventional face-to-face intervention. The aim of the present study was to compared language and cognitive training delivered to patients from a distance, through telecommunication systems, for the same intervention conducted on a face-to-face mode in patients with multi domain amnestic MCI (md-aMCI). To this end, 30 patients diagnosed with md-aMCI took part in the present study. The participants divided into two groups; one group received conventional face-to-face training and the other group received Telerehabilitation training. Both groups received language training using paper and pencil tasks and cognitive training using the Rehacom software. The training lasted 15 weeks and was delivered twice a week, for 60 minutes per session. The conventional face-to-face mode had a significant impact on cognitive (delayed and working memory, processing speed, executive function, and attention) and language domains (naming, word recognition, and semantic fluency). The telerehabilitation method had a beneficial impact on delayed memory, naming, and semantic fluency. The results of our study provide evidence that both telerehabilitation and face-to-face language and cognitive training seem to have a positive impact in patients with md-aMCI, with face-to-face training improving more domains than telerehabilitation.

Evaluation of the Efficacy and Feasibility of a Telerehabilitation Program Using Language and Cognitive Exercises in Multi-Domain Amnestic Mild Cognitive Impairment

OBJECTIVE

The aim of the present study was to investigate the efficacy and feasibility of a telerehabilitation program in multi-domain amnestic Mild Cognitive Impairment (md-aMCI). The study sample consisted of 30 patients with md-aMCI and aged 60-80 years.

METHODS

The participants were randomly divided into two groups. The Training Group (TG), which received cognitive training by using the RehaCom software as well as paper-pencil language training and the Control Group (CG) which received standard clinical care (e.g., psychotherapy or/and physiotherapy). Duration of the telerehabilitation intervention was 15 weeks (twice a week for 60 min/session).

RESULTS

Our results revealed that the neuropsychological performance of the TG group after the telerehabilitation intervention improved on a statistically significant level on the domains of delayed and working memory, confrontation naming, verbal fluency, and global cognition. Comparison between the TG and CG revealed a significant impact of the telerehabilitation program on the domains of memory (delay and working) and language (naming and verbal fluency) as well as global cognition performance.

CONCLUSION

The findings of the study are promising in that the telerehabilitation intervention appears to be a useful method in improving or stabilizing cognitive decline in md-aMCI individuals and was a particularly effective alternative approach during the period of the pandemic lockdown. Specifically, the beneficial impact of the telerehabilitation intervention on episodic memory (which is one of the first domains to show impairment in md-aMCI patients) provides us with hope and evidence that these types of interventions may be applied with similar success using face-to-face interventions.

User Experience during an Immersive Virtual Reality-Based Cognitive Task: A Comparison between Estonian and Italian Older Adults with MCI

Mild cognitive impairment (MCI) is an early stage of cognitive abilities loss and puts older adults at higher risk of developing dementia. Virtual reality (VR) could represent a tool for the early assessment of this pathological condition and for administering cognitive training. This work presents a study evaluating the acceptance and the user experience of an immersive VR application representing a supermarket. As the same application had already been assessed in Italy, we aimed to perform the same study in Estonia in order to compare the outcomes in the two populations. Fifteen older adults with MCI were enrolled in one Rehabilitation Center of Estonia and tried the supermarket once. Afterwards, they were administered questionnaires aimed at evaluating their technology acceptance, sense of presence, and cybersickness. Estonian participants reported low side effects and discrete enjoyment, and a sense of presence. Nonetheless, their intention to use the technology decreased after the experience. The comparison between Italian and Estonian older adults showed that cybersickness was comparable, but technology acceptance and sense of presence were significantly lower in the Estonian group. Thus, we argue that: (i) cultural and social backgrounds influence technology acceptance; (ii) technology acceptance was rather mediated by the absence of positive feelings rather than cybersickness.

Effectiveness of exercise and physical activity interventions to improve long-term patient-relevant cognitive and non-cognitive outcomes in people living with mild cognitive impairment: a protocol of a systematic review and meta-analysis

INTRODUCTION

Mild cognitive impairment (MCI) is a clinical syndrome characterised by persistent cognitive deficits that do not yet fulfil the criteria of dementia. Delaying the onset of dementia using secondary preventive measures such as physical activity and exercise can be a safe way of reducing the risk of further cognitive decline and maintaining independence and improving quality of life. The aim is to systematically review the literature to assess the effectiveness of physical activity and exercise interventions to improve long-term patient-relevant cognitive and non-cognitive outcomes in people living with MCI, including meta-analyses if applicable.

METHODS AND ANALYSIS

We will systematically search five electronic databases from 1995 onward to identify trials reporting on the effectiveness of physical activity and exercise interventions to improve long-term (12+ months) patient-relevant cognitive and non-cognitive outcomes in adults (50+ years) with MCI. Screening procedures, selection of eligible full-texts, data extraction and risk of bias assessment will be performed in dual-review mode. Additionally, the reporting quality of the exercise interventions will be assessed using the Consensus on Exercise Reporting Template. A quantitative synthesis will only be conducted if studies are homogeneous enough for effect sizes to be pooled. Where quantitative analysis is not applicable, data will be represented in a tabular form and synthesised narratively. People living with MCI will be involved in defining outcome measures most relevant to them in order to assess in how far randomised controlled trials report endpoints that matter to those concerned.

ETHICS AND DISSEMINATION

Results will be disseminated to both scientific and lay audiences by creating a patient-friendly video abstract. This work will inform professionals in primary care about the effectiveness of physical activity and exercise interventions and support them to make evidence-based exercise recommendations for the secondary prevention of dementia in people living with MCI. No ethical approval required.

PROSPERO REGISTRATION NUMBER

CRD42021287166.

Metabolic Disturbances Induced by Sleep Restriction as Potential Triggers for Alzheimer's Disease

Sleep has a major role in learning, memory consolidation, and metabolic function. Although it is known that sleep restriction increases the accumulation of amyloid β peptide (Aβ) and the risk to develop Alzheimer's disease (AD), the mechanism behind these effects remains unknown. In this review, we discuss how chronic sleep restriction induces metabolic and cognitive impairments that could result in the development of AD in late life. Here, we integrate evidence regarding mechanisms whereby metabolic signaling becomes disturbed after short or chronic sleep restriction in the context of cognitive impairment, particularly in the accumulation of Aβ in the brain. We also discuss the role of the blood-brain barrier in sleep restriction with an emphasis on the transport of metabolic signals into the brain and Aβ clearance. This review presents the unexplored possibility that the alteration of peripheral metabolic signals induced by sleep restriction, especially insulin resistance, is responsible for cognitive deficit and, subsequently, implicated in AD development.

Is Attention-Deficit/Hyperactivity Disorder a Risk Syndrome for Parkinson's Disease?

Recent epidemiological evidence indicates that diagnosis of attention-deficit/hyperactivity disorder (ADHD) is associated with increased risk for diseases of the basal ganglia and cerebellum, including Parkinson's disease (PD). The evidence reviewed here indicates that deficits in striatal dopamine are a shared component of the causal chains that produce these disorders. Neuropsychological studies of adult ADHD, prodromal PD, and early-stage PD reveal similar deficits in executive functions, memory, attention, and inhibition that are mediated by similar neural substrates. These and other findings are consistent with the possibility that ADHD may be part of the PD prodrome. The mechanisms that may mediate the association between PD and ADHD include neurotoxic effects of stimulants, other environmental exposures, and Lewy pathology. Understanding the nature of the association between PD and ADHD may provide insight into the etiology and pathogenesis of both disorders. The possible contribution of stimulants to this association may have important clinical and public health implications.

Impairment of Everyday Spatial Navigation Abilities in Mild Cognitive Impairment Is Weakly Associated with Reduced Grey Matter Volume in the Medial Part of the Entorhinal Cortex

BACKGROUND

Research in rodents identified specific neuron populations encoding information for spatial navigation with particularly high density in the medial part of the entorhinal cortex (ERC), which may be homologous with Brodmann area 34 (BA34) in the human brain.

OBJECTIVE

The aim of this study was to test whether impaired spatial navigation frequently occurring in mild cognitive impairment (MCI) is specifically associated with neurodegeneration in BA34.

METHODS

The study included baseline data of MCI patients enrolled in the Alzheimer's Disease Neuroimaging Initiative with high-resolution structural MRI, brain FDG PET, and complete visuospatial ability scores of the Everyday Cognition test (VS-ECog) within 30 days of PET. A standard mask of BA34 predefined in MNI space was mapped to individual native space to determine grey matter volume and metabolic activity in BA34 on MRI and on (partial volume corrected) FDG PET, respectively. The association of the VS-ECog sum score with grey matter volume and metabolic activity in BA34, APOE4 carrier status, age, education, and global cognition (ADAS-cog-13 score) was tested by linear regression. BA28, which constitutes the lateral part of the ERC, was used as control region.

RESULTS

The eligibility criteria led to inclusion of 379 MCI subjects. The VS-ECog sum score was negatively correlated with grey matter volume in BA34 (β= -0.229, p = 0.022) and age (β= -0.124, p = 0.036), and was positively correlated with ADAS-cog-13 (β= 0.175, p = 0.003). None of the other predictor variables contributed significantly.

CONCLUSION

Impairment of spatial navigation in MCI is weakly associated with BA34 atrophy.

Associations of 4AT with mobility, length of stay and mortality in hospital and discharge destination among patients admitted with hip fractures

BACKGROUND

the 4AT (Alertness, Abbreviated Mental Test-4, Attention and Acute change or fluctuating course), a tool to screen cognitive impairment and delirium, has recently been recommended by the Scottish Intercollegiate Guidelines Network. We examined its ability to predict health outcomes among patients admitted with hip fractures to a single hospital between January 2018 and June 2019.

METHODS

the 4AT was performed within 1 day after hip surgery. A 4AT score of 0 means unlikely delirium or severe cognitive impairment (reference group); a score of 1-3 suggests possible chronic cognitive impairment, without excluding possibility of delirium; a score ≥ 4 suggests delirium with or without chronic cognitive impairment. Logistic regression, adjusted for: age; sex; nutritional status; co-morbidities; polypharmacy; and anticholinergic burden, used the 4AT to predict mobility, length of stay (LOS), mortality and discharge destination, compared with the reference group.

RESULTS

from 537 (392 women, 145 men: mean = 83.7 ± standard deviation [SD] = 8.8 years) consecutive patients, 522 completed the 4AT; 132 (25%) had prolonged LOS (>2 weeks) and 36 (6.8%) died in hospital. Risk of failure to mobilise within 1 day of surgery was increased with a 4AT score ≥ 4 (OR = 2.4, 95% confidence interval [CI] = 1.3-4.3). Prolonged LOS was increased with 4AT scores of 1-3 (OR = 2.4, 95%CI = 1.4-4.1) or ≥4 (OR = 3.1, 95%CI = 1.9-6.7). In-patient mortality was increased with a 4AT score ≥ 4 (OR = 3.1, 95%CI = 1.2-8.2) but not with a 4AT score of 1-3. Change of residence on discharge was increased with a 4AT score ≥ 4 (OR = 3.1, 95%CI = 1.4-6.8). These associations persisted after excluding patients with dementia. 4AT score = 1-3 and ≥ 4 associated with increased LOS by 3 and 6 days, respectively.

CONCLUSIONS

for older adults with hip fracture, the 4AT independently predicts immobility, prolonged LOS, death in hospital and change in residence on discharge.

The associated volumes of sub-cortical structures and cognitive domain in patients of Mild Cognitive Impairment

This study aimed to explore the relationship between sub-cortical structures alterations and the cognitive domains in Mild Cognitive Impairment (MCI) patients, expected to find identifying sub-cortical structure markers of MCI progression to dementia. A total of 67 MCI patients (8 subjects refused to follow up) were recruited, who were divided into 21 stable MCI (sMCI) and 38 progress MCI (pMCI), according to cognitive assays. FreeSurfer software was used to perform volumetric measurements of the sub-cortical structures from 3.0 T magnetic resonance scans. Data revealed that pMCI subjects had lower scores in memory, language, executive and visual spatial compared with sMCI subjects. Compared with the sMCI group, the volume of the left thalamus, bilateral hippocampus, corpus callosum posterior and corpus callosum central was smaller in pMCI subjects. Partial correlation and general linear regression analysis showed that the left hippocampus was predicted region for memory, left thalamus was predicted region for language, executive and visual spatial. These current results suggest that the volumes of sub-cortical structures in stable MCI and progress MCI patients were heterogeneous. Among these regions, the left hippocampus was predicted region for memory, left thalamus was predicted region for language, executive and visual spatial, suggesting that these structures might be important for detecting the subtle effects of MCI patients' cognitive domain or to assess the effectiveness of therapeutic intervention for MCI.

Alterations of Effective Connectivity Patterns in Mild Cognitive Impairment: An MEG Study

Neuroimaging techniques have demonstrated over the years their ability to characterize the brain abnormalities associated with different neurodegenerative diseases. Among all these techniques, magnetoencephalography (MEG) stands out by its high temporal resolution and noninvasiveness. The aim of the present study is to explore the coupling patterns of resting-state MEG activity in subjects with mild cognitive impairment (MCI). To achieve this goal, five minutes of spontaneous MEG activity were acquired with a 148-channel whole-head magnetometer from 18 MCI patients and 26 healthy controls. Inter-channel relationships were investigated by means of two complementary coupling measures: coherence and Granger causality. Coherence is a classical method of functional connectivity, while Granger causality quantifies effective (or causal) connectivity. Both measures were calculated in the five conventional frequency bands: delta (δ, 1-4 Hz), theta (θ, 4-8 Hz), alpha (α, 8-13 Hz), beta (β, 13-30 Hz), and gamma (γ, 30-45 Hz). Our results showed that connectivity values were lower for MCI patients than for controls in all frequency bands. However, only Granger causality revealed statistically significant differences between groups (p-values < 0.05, FDR corrected Mann-Whitney U-test), mainly in the beta band. Our results support the role of MCI as a disconnection syndrome, which elicits early alterations in effective connectivity patterns. These findings can be helpful to identify the neural substrates involved in prodromal stages of dementia.

Expectant futures and an early diagnosis of Alzheimer's disease: Knowing and its consequences

Efforts to diagnose Alzheimer's disease (AD) at earlier stages as a means to managing the risks of an ageing population, dominate scientific research and healthcare policy in the UK. It is anticipated that early diagnosis will maximise treatment options and enable patients to 'prepare for their future' in terms of care. Drawing on qualitative data gathered across an out-patient memory service and in-patient hospital in the UK, the purpose of this paper is to examine the ways in which the hopeful promissory claims of early diagnosis as it maintains the dominant biomedical model for managing AD, are negotiated by healthcare practitioners. Developing the analytical standpoint of the sociology of expectations, this paper demonstrates that early diagnosis has the potential to 'close off' hopeful promissory visions of the future in two ways. Firstly, it (re)produces the fearful anticipations of AD built around expectations concerning the ageing future 'self', and secondly it produces uncertainty in terms of the availability of care as material resource. Whilst practitioners account for the uncertainties and anxieties it produces for patients and their families, they also convey a sense of ambivalence concerning early diagnosis. This article captures the internal conflicts and contradictions inherent to practitioners' perspectives regarding the repercussions of early diagnosis and concludes by arguing that it effaces the uncertainties and anxieties that it produces in practice as it restricts the co-existence of narratives for making sense of memory loss beyond 'loss of self', and fails to recognise care as a viable alternative for managing AD.

Olfactory evaluation in Mild Cognitive Impairment: correlation with neurocognitive performance and endothelial function

Mild Cognitive Impairment (MCI) is an intermediate condition between normal aging and dementia, associated with an increased risk of progression into the latter within months or years. Olfactory impairment, a well-known biomarker for neurodegeneration, might be present in the condition early, possibly representing a signal for future pathological onset. Our study aimed at evaluating olfactory function in MCI and healthy controls in relation to neurocognitive performance and endothelial function. A total of 85 individuals with MCI and 41 healthy controls, matched for age and gender, were recruited. Olfactory function was assessed by Sniffin' Sticks Extended Test (Burghart, Medizintechnik, GmbH, Wedel, Germany). A comprehensive neurocognitive assessment was performed. Endothelial function was assessed by flow-mediated dilation (FMD) of the brachial artery by ultrasound. MCI individuals showed an impaired olfactory function compared to controls. The overall olfactory score is able to predict MCI with a good sensitivity and specificity (70.3 and 77.4% respectively). In MCI, olfactory identification score is correlated with a number of neurocognitive abilities, including overall cognitive status, dementia rating, immediate and delayed memory, visuospatial ability and verbal fluency. FMD was reduced in MCI (2.90 ± 2.15 vs. 3.66 ± 1.96%, P = 0.016) and was positively associated with olfactory identification score (ρ_s =0.219, P = 0.025). The association remained significant after controlling for age, gender, and smoking. In conclusion, olfactory evaluation is able to discriminate between MCI and healthy individuals. Systemic vascular dysfunction might be involved, at least indirectly, in olfactory dysfunction in MCI.

Scoring systems for the Clock Drawing Test: A historical review

The Clock Drawing Test (CDT) is a simple neuropsychological screening instrument that is well accepted by patients and has solid psychometric properties. Several different CDT scoring methods have been developed, but no consensus has been reached regarding which scoring method is the most accurate. This article reviews the literature on these scoring systems and the changes they have undergone over the years. Historically, different types of scoring systems emerged. Initially, the focus was on screening for dementia, and the methods were both quantitative and semi-quantitative. Later, the need for an early diagnosis called for a scoring system that can detect subtle errors, especially those related to executive function. Therefore, qualitative analyses began to be used for both differential and early diagnoses of dementia. A widely used qualitative method was proposed by Rouleau et al. (1992). Tracing the historical path of these scoring methods is important for developing additional scoring systems and furthering dementia prevention research.

Longitudinal FDG-PET features for the classification of Alzheimer's disease

The majority of existing computer-aided diagnosis (CAD) schemes for Alzheimer's disease (AD) rely on the analysis of biomarkers at a single time-point, ignoring the progressive nature of the disorder. Recently, a method was proposed by Gray et al. [1] for the multi-region analysis of longitudinal fluorodeoxyglucose positron emission tomography (FDG-PET) images which reported classification improvements by using regional signal intensities combined with regional change over a 12 month period. In this paper we extend the approach proposed in [1] to the analysis of the entire brain pattern. Compared to [1], our method uses voxel-wise differences and avoids segmentation of the images into regions of interest. For our study, FDG-PET scans at the baseline and at 12-month follow-up of cognitively normal (CN), mild cognitive impairment (MCI) and AD subjects were retrieved from the Alzheimer's disease neuroimaging initiative (ADNI) database. For both AD and MCI identification, the best classification results were achieved by combining cross-sectional and longitudinal information rather than using only the cross-sectional data. Furthermore, the longitudinal voxel-based analysis outperformed multi-region analysis.

Examination of Variables That May Affect the Relationship Between Cognition and Functional Status in Individuals with Mild Cognitive Impairment: A Meta-Analysis

The objective of this meta-analysis was to improve understanding of the heterogeneity in the relationship between cognition and functional status in individuals with mild cognitive impairment (MCI). Demographic, clinical, and methodological moderators were examined. Cognition explained an average of 23% of the variance in functional outcomes. Executive function measures explained the largest amount of variance (37%), whereas global cognitive status and processing speed measures explained the least (20%). Short- and long-delayed memory measures accounted for more variance (35% and 31%) than immediate memory measures (18%), and the relationship between cognition and functional outcomes was stronger when assessed with informant-report (28%) compared with self-report (21%). Demographics, sample characteristics, and type of everyday functioning measures (i.e., questionnaire, performance-based) explained relatively little variance compared with cognition. Executive functioning, particularly measured by Trails B, was a strong predictor of everyday functioning in individuals with MCI. A large proportion of variance remained unexplained by cognition.

Treatment for mild cognitive impairment: a systematic review and meta-analysis

BACKGROUND

The effectiveness of treatments for mild cognitive impairment is uncertain. The aim of this review was to evaluate the effectiveness and harms of treatment for mild cognitive impairment in adults 65 years of age and older.

METHODS

We searched MEDLINE, Embase and Cochrane Central (December 2012-December 2014); citations from 2 systematic reviews were considered for inclusion. We included randomized controlled trials involving community-dwelling adults aged 65 years and older with a diagnosis of mild cognitive impairment. Studies reporting on cognition, function, behaviour, global status, mortality and adverse events for treatment with pharmacologic and nonpharmacologic interventions were included.

RESULTS

Seventeen studies were included. Cholinesterase inhibitor studies evaluating cognition (Alzheimer's Disease Assessment Scale, cognition subscale) showed no difference between intervention and control groups (mean difference [MD] -0.33, 95% CI -0.73 to 0.06]; one behavioural study showed no significant effect on cognition (Alzheimer's Disease Assessment Scale, cognition subscale) for the intervention group when compared to controls (MD -0.60, (95% CI -1.44 to 0.24), and one study on vitamin E showed no difference between intervention and control groups (MD 0.85, 95% CI -0.32 to 2.02). With the Mini-Mental State Examination, cholinesterase inhibitors showed no difference between intervention and control groups (MD 0.17, 95% CI -0.13 to 0.47); behavioural studies showed a significant difference favouring intervention (MD 1.01, 95% CI 0.25 to 1.77), and studies of dietary supplements and/or vitamins showed no difference between intervention and control groups (MD 0.20, 95% CI -0.04 to 0.43). Pharmacologic studies showed no difference in serious adverse events (risk ratio 0.98, 95% CI 0.86 to 1.10). No serious adverse events were reported for nonpharmacologic interventions.

INTERPRETATION

Treatment of mild cognitive impairment with cholinesterase inhibitors showed no benefit when compared with a control group. A small cognitive benefit was observed using behavioural therapies when compared with the control group. However, the clinical significance of this small benefit remains uncertain. The current evidence does not support the use of cholinesterase inhibitors for treating mild cognitive impairment, and future high-quality research using a standardized approach is needed to affirm the finding of a small benefit on cognition that was observed for behavioural interventions.

REGISTRATION

PROSPERO no. CRD42014015431.

Cognitive frailty, a novel target for the prevention of elderly dependency

Frailty is a complex and heterogeneous clinical syndrome. Cognitive frailty has been considered as a subtype of frailty. In this study, we refine the definition of cognitive frailty based on existing reports about frailty and the latest progress in cognition research. We obtain evidence from the literature regarding the role of pre-physical frailty in pathological aging. We propose that cognitive impairment of cognitive frailty results from physical or pre-physical frailty and comprises two subtypes: the reversible and the potentially reversible. Reversible cognitive impairment is indicated by subjective cognitive decline (SCD) and/or positive fluid and imaging biomarkers of amyloid-β accumulation and neurodegeneration. Potentially reversible cognitive impairment is MCI (CDR=0.5). Based on the severity of cognitive impairment, it is possible to determine the primary and secondary preventative measures for cognitive frailty. We further determine whether SCD is a component of pre-clinical AD or the early stage of other neurodegenerative diseases, which is required for guiding personal clinical intervention.

The impact of early life factors on cognitive function in old age: The Hordaland Health Study (HUSK)

Background

Previous studies have shown that adverse conditions during fetal and early life are associated with lower performance on neurocognitive tests in childhood, adolescence and adult life. There is, however, a paucity in studies investigating these associations into old age. The aim was to investigate the impact of early life factors on cognitive function in old age by taking advantage of the potential for a linkage between a community survey and historical birth records.

Methods

A historical cohort study employing a linkage between a community survey of people aged 72–74 years with the participants’ birth records (n=346). Early life factors included anthropometric measures taken at birth, birth complications, parental socioeconomic status, and maternal health status. The main outcome was a z-scored composite cognitive score, based on test scores from Kendrick Object Learning Test, Trail Making Test A, a modified version of the Digit Symbol Test, Block Design, a modified version of Mini-Mental State Examination and an abridged version of the Controlled Oral Word Association Test (COWAT). The separate cognitive tests were also individually analysed in relation to measures identified at birth.

Results

Higher parental socioeconomic status (SES; based on father’s occupation) was associated with a higher value on the composite cognitive score (by 0.25 SD, p=0.0146) and higher Digit Symbol and Trail Making Test A performance. Higher head circumference at birth was associated with higher COWAT and Trail Making Test A performance. Both higher parental SES and head circumference at birth predicted cognitive function in old age independently of each other. There were no other consistent associations.

Conclusions

In general we found little evidence for a substantial role of early life factors on late-life cognitive function. However, there was some evidence for an association with parental SES status and head circumference on certain cognitive domains.

Clinical features of MCI: motor changes

Mild cognitive impairment (MCI) is a classification reserved for nondemented elderly individuals at increased risk for future decline to dementia, compared to those with normal cognition. Cognitive tests, particularly those assessing verbal recall, have been found to be useful in the identification of elderly people with MCI. We argue that a variety of motor/psychomotor evaluations are also sensitive to MCI. Motor assessments described as complex correctly categorize normal versus MCI elderly with comparable accuracies to those obtained by cognitive tests. Unlike performance on verbally based cognitive measures, motor-test scores appear to be relatively independent of educational attainment, indicating that the use of certain motor tests may be particularly valuable in the identification of MCI among elderly with widely varying educational backgrounds.