Mild cognitive impairment clinical trials

Effect of digital technology interventions for cognitive function improvement in mild cognitive impairment and dementia: A systematic review and meta-analysis

The development and commercialization of digital therapeutics are increasing. The aim of this study was to determine the effects of digital technology interventions on cognitive function, thereby providing evidence for the development and practical application of interventions to manage cognitive function in patients with mild cognitive impairment and dementia. We conducted a systematic review and meta-analysis of randomized controlled trials according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. Randomized controlled trials on digital technology interventions published until April 2023 were searched in PubMed, Embase, Cochrane Library, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases without a period limit. Articles that identified the effects of digital technology interventions on cognitive function improvement in dementia and mild cognitive impairment were integrated and analyzed. RevMan software 5.4 was used for quality assessment and meta-analysis. Twelve out of 708 studies were included in the review and meta-analysis. Digital technology interventions had significant effects on global cognitive function (standardized mean difference [SMD] = 0.31; 95% confidence interval [CI] = 0.04-0.57; p = 0.02; I² = 60%). In addition, these interventions had significant effects on neuropsychological characteristics, including attention (SMD = 1.17; 95% CI = 0.36-1.97; p = 0.004; I² = 84%), visuospatial perception (SMD = 0.68; 95% CI = 0.19-1.17; p = 0.006; I² = 57%), and memory (SMD = 0.45; 95% CI = 0.19-0.71; p = 0.0007; I² = 22%). The results suggest that digital technology interventions help improve cognitive function in patients with dementia and mild cognitive impairment.

Digital Cognitive Assessment Tests for Older Adults: Systematic Literature Review

BACKGROUND

The global health pandemic has affected the increasing older adult population, especially those with mental illnesses. It is necessary to prevent cases of cognitive impairment in adults early on, and this requires the support of information and communication technologies for evaluating and training cognitive functions. This can be achieved through computer applications designed for cognitive assessment.

OBJECTIVE

In this review, we aimed to assess the state of the art of the current platforms and digital test applications for cognitive evaluation, with a focus on older adults.

METHODS

A systematic literature search was conducted on 3 databases (Web of Science, PubMed, and Scopus) to retrieve recent articles on the applications of digital tests for cognitive assessment and analyze them based on the methodology used. Four research questions were considered. Through the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology, following the application of inclusion and exclusion criteria, a total of 20 articles were finally reviewed.

RESULTS

Some gaps and trends were identified regarding the types of digital applications and technologies used, the evaluated effects on cognitive domains, and the psychometric parameters and personal characteristics considered for validation.

CONCLUSIONS

Computerized tests (similar to paper-and-pencil tests) and test batteries (on computers, tablets, or web platforms) were the predominant types of assessments. Initial studies with simulators, virtual environments, and daily-life activity games were also conducted. Diverse validation methods and psychometric properties were observed; however, there was a lack of evaluations that involved specific populations with diverse education levels, cultures, and degrees of technology acceptance. In addition, these evaluations should consider emotional and usability aspects.

Gamma neuromodulation improves episodic memory and its associated network in amnestic mild cognitive impairment: a pilot study

Amnestic mild cognitive impairment (aMCI) is a predementia stage of Alzheimer's disease associated with dysfunctional episodic memory and limited treatment options. We aimed to characterize feasibility, clinical, and biomarker effects of noninvasive neurostimulation for aMCI. 13 individuals with aMCI received eight 60-minute sessions of 40-Hz (gamma) transcranial alternating current stimulation (tACS) targeting regions related to episodic memory processing. Feasibility, episodic memory, and plasma Alzheimer's disease biomarkers were assessed. Neuroplastic changes were characterized by resting-state functional connectivity (RSFC) and neuronal excitatory/inhibitory balance. Gamma tACS was feasible and aMCI participants demonstrated improvement in multiple metrics of episodic memory, but no changes in biomarkers. Improvements in episodic memory were most pronounced in participants who had the highest modeled tACS-induced electric fields and exhibited the greatest changes in RSFC. Increased RSFC was also associated with greater hippocampal excitability and higher baseline white matter integrity. This study highlights initial feasibility and the potential of gamma tACS to rescue episodic memory in an aMCI population by modulating connectivity and excitability within an episodic memory network.

The effect of plasma cortisol on hippocampal atrophy and clinical progression in mild cognitive impairment

Introduction

Both elevated cortisol and hippocampal volume have been linked to an increased risk for the development of Alzheimer's disease (AD). This longitudinal study assessed the effects of plasma cortisol on hippocampal atrophy and clinical progression rates in patients with mild cognitive impairment (MCI).

Methods

Patients with amnestic MCI (n = 304) were selected from the Alzheimer's Disease Neuroimaging Initiative (ADNI) based on availability of baseline plasma cortisol and hippocampal volume measures, assessed at baseline and during follow-ups. We investigated associations between plasma cortisol, hippocampal volume, and risk of clinical progression to AD over a study period of up to 100 months (mean follow-up time 36.8 months) using linear mixed models, Cox proportional hazards models, and Kaplan-Meier estimators.

Results

Plasma cortisol predicted greater hippocampal atrophy, such that participants with higher cortisol showed faster decline in hippocampal volume over time (interaction: β = -0.15, p = 0.004). Small hippocampal volume predicted a higher risk of clinical progression to AD (haard ratio [HR] = 2.15; confidence in terval [CI], 1.64-2.80; p < 0.001). A similar effect was not found for cortisol (HR = 1.206; CI, 0.82-1.37; p = 0.670) and there was no statistical evidence for an interaction between hippocampal volume and cortisol on clinical progression (HR = 0.81; CI, 0.57-0.17; p = 0.260).

Discussion

Our findings suggest that higher cortisol predicts higher hippocampal atrophy, which in turn is a risk factor for progression to AD. Regulation of the hypothalamic-pituitary-adrenal axis through stress-reducing lifestyle interventions might be a protective factor against hippocampal degeneration at the prodromal stage of AD.

The effects of herbal medicine (Jujadokseo-hwan) on quality of life in patients with mild cognitive impairment: Cost-effectiveness analysis alongside randomized controlled trial

Background

Mild cognitive impairment (MCI), the early stage of dementia, requires effective intervention for symptom management and improving patients' quality of life (QoL). Jujadokseo-hwan (JDH) is a Korean herbal medicine prescription used to improve MCI symptoms, such as memory deficit. This study evaluates the improvement in QoL through JDH. Alongside a clinical trial, it estimates the cost-effectiveness of JDH, compared to placebo, for MCI over 24 weeks.

Methods

Changes in QoL were measured using the EuroQol-5 Dimensions (EQ-5D) and Korean version QoL-Alzheimer's Disease (KQOL-AD). Direct medical and non-medical costs were surveyed and incremental cost-effectiveness ratios (ICER) per QALY for JDH were produced.

Results

In total, 64 patients were included in the economic evaluation (n = 35 in JDH, n = 29 in placebo). In the JDH group, EQ-5D and KQOL-AD improved by 0.020 (p = .318) and 3.40 (p = .011) over 24 weeks, respectively. In the placebo group, they increased by 0.001 (p=.920) and 1.07 (p=.130), respectively. The ICER was KRW 76,400,000 per QALY and KRW 108,000 per KQOL-AD for JDH, compared to the placebo group.

Conclusion

JDH is not considered a cost-effective treatment option compared with placebo; however, it positively affects QoL improvement in patients with MCI.

Is physical exercise effective at improving body structure & function and activity outcomes in individuals with Mild Cognitive Impairment? a systematic review with quality of evidence assessment

PURPOSE

To investigate the effect of physical exercise on body structure & function and activity outcomes in individuals with Mild Cognitive Impairment (MCI).

METHODS

Six databases were searched from inception until January 2021. Randomized controlled trials (RCTs) comparing physical exercise with a control group were included.

RESULTS

Fourteen RCTs were included. Three types of physical exercise were identified: aerobic (AE), resistance (RE), and multimodal (ME). Regarding body structure & function outcomes, evidence for RE was very low and with effect for improvement in upper limb muscle strength and very low and without effect for lower limbs. For improvement in postural balance, evidence was very low and with effect with AE and very low and without effect with RE and ME. Evidence for cardiorespiratory function was very low and without effect with AE and RE. Regarding activity outcomes, evidence was low and without effect for mobility with AE and very low and without effect with RE and ME.

CONCLUSIONS

Physical exercise promoted improvements in body structure & function outcomes in individuals with MCI. Resistance exercise improvement upper limb muscle strength and AE enhanced postural balance. In contrast, physical exercise did not promote a significant benefit in activity outcomes.Implications for rehabilitationResults of this systematic review have shown that physical exercise promoted improvements in body structure & function outcomes in individuals with Mild Cognitive Impairment (MCI).Resistance exercise with elastic bands for approximately 60 minutes twice a week for a total of three months improved upper limb muscle strength.Aerobic exercise with walking for approximately 60 minutes twice per week for a total of six months enhanced postural balance.Considering the potential benefits identified in this systematic review, physical exercise can be recommended for individuals with MCI.We also highlight the importance of the use of the International Classification of Functioning, Disability and Health for rehabilitation planning.

A review on Alzheimer's disease classification from normal controls and mild cognitive impairment using structural MR images

Alzheimer's disease (AD) is an irreversible neurodegenerative brain disorder that degrades the memory and cognitive ability in elderly people. The main reason for memory loss and reduction in cognitive ability is the structural changes in the brain that occur due to neuronal loss. These structural changes are most conspicuous in the hippocampus, cortex, and grey matter and can be assessed by using neuroimaging techniques viz. Positron Emission Tomography (PET), structural Magnetic Resonance Imaging (MRI) and functional MRI (fMRI), etc. Out of these neuroimaging techniques, structural MRI has evolved as the best technique as it indicates the best soft tissue contrast and high spatial resolution which is important for AD detection. Currently, the focus of researchers is on predicting the conversion of Mild Cognitive Impairment (MCI) into AD. MCI represents the transition state between expected cognitive changes with normal aging and Alzheimer's disease. Not every MCI patient progresses into Alzheimer's disease. MCI can develop into stable MCI (sMCI, patients are called non-converters) or into progressive MCI (pMCI, patients are diagnosed as MCI converters). This paper discusses the prognosis of MCI to AD conversion and presents a review of structural MRI-based studies for AD detection. AD detection framework includes feature extraction, feature selection, and classification process. This paper reviews the studies for AD detection based on different feature extraction methods and machine learning algorithms for classification. The performance of various feature extraction methods has been compared and it has been observed that the wavelet transform-based feature extraction method would give promising results for AD classification. The present study indicates that researchers are successful in classifying AD from Normal Controls (N_rmC) but, it still requires a lot of work to be done for MCI/ N_rmC and MCI/AD, which would help in detecting AD at its early stage.

Vesicular Glutamate Transporter Changes in the Cortical Default Mode Network During the Clinical and Pathological Progression of Alzheimer's Disease

BACKGROUND

Altered glutamatergic neurotransmission may contribute to impaired default mode network (DMN) function in Alzheimer's disease (AD). Among the DMN hub regions, frontal cortex (FC) was suggested to undergo a glutamatergic plasticity response in prodromal AD, while the status of glutamatergic synapses in the precuneus (PreC) during clinical-neuropathological AD progression is not known.

OBJECTIVE

To quantify vesicular glutamate transporter VGluT1- and VGluT2-containing synaptic terminals in PreC and FC across clinical stages of AD.

METHODS

Unbiased sampling and quantitative confocal immunofluorescence of cortical VGluT1- and VGluT2-immunoreactive profiles and spinophilin-labeled dendritic spines were performed in cases with no cognitive impairment (NCI), mild cognitive impairment (MCI), mild-moderate AD (mAD), or moderate-severe AD (sAD).

RESULTS

In both regions, loss of VGluT1-positive profile density was seen in sAD compared to NCI, MCI, and mAD. VGluT1-positive profile intensity in PreC did not differ across groups, while in FC it was greater in MCI, mAD, and sAD compared to NCI. VGluT2 measures were stable in PreC while FC had greater VGluT2-positive profile density in MCI compared to sAD, but not NCI or mAD. Spinophilin measures in PreC were lower in mAD and sAD compared to NCI, while in FC they were stable across groups. Lower VGluT1 and spinophilin measures in PreC, but not FC, correlated with greater neuropathology.

CONCLUSION

Frank loss of VGluT1 in advanced AD relative to NCI occurs in both DMN regions. In FC, an upregulation of VGluT1 protein content in remaining glutamatergic terminals may contribute to this region's plasticity response in AD.

Analysis of the Clock-Reading Ability in Patients with Cognitive Impairment: Comparison of Analog Clocks and Digital Clocks

Background: Time disorientation is one of the main symptoms observed in patients with dementia; however, their clock-reading ability has not been fully reported. Objective: This study aimed to investigate the clock-reading ability of both digital and analog clocks in patients with dementia. We newly devised the clock-reading test (CRT) and the number-reading test (NRT) to assess cognitive factors that may affect clock-reading ability. Furthermore, the discriminating power of the CRT was calculated. Methods: 104 participants were categorized based on their Mini-Mental State Examination (MMSE) scores as follows: subjective cognitive decline ∼ mild cognitive impairment (SCD∼MCI, N = 43), early Alzheimer’s disease (AD) (N = 26), and middle-to-late AD (N = 35). Their cognitive abilities were evaluated using the clock-drawing test (CDT), CRT, and NRT. Results: Cognitive decline leads to impairment of clock-reading ability which is more pronounced in the analog clocks than digital ones. This deficit in clock-reading is attributed to a loss of semantic memory regarding clocks at all stages. Additionally, visuospatial dysfunction and reduced ability of number recognition may lead to deficit in clock-reading in the advanced stage of AD. The discriminating power of the CRT (analog) (AUC = 0.853) was high enough to detect cognitive decline. Conclusion: Digital clocks are more readable by patients with dementia. Since reading clocks is closely associated with daily life, the CRT has proved to be a useful tool. A decline of analog clock-reading may be an early detector for the onset of dementia in elderly patients.

Can mild cognitive impairment with depression be improved merely by exercises of recall memories accompanying everyday conversation? A longitudinal study 2016-2019

Purpose

The purpose of this study is to find out a simple cognitive intervention method to use MCI and suffering people with depression. As the elderly society increases around the world, the number of elderly people with diseases and dementia is increasing rapidly. Mild cognitive impairment (MCI), a pre-stage to dementia, is a critical treatment time to slow disease progression. However, there is currently no appropriate medication. Furthermore, MCI patients with depression are more difficult to treat.

Design/methodology/approach

To overcome these problems, the authors confirmed improvements and delayed effects in MCI patients in this study for three years through cognitive intervention, demonstrating its effectiveness. Cognitive interventions were conducted for memory retrieval and steadily stimulated the brain by performing tasks to solve problems during daily conversations.

Findings

As a result, the intervention group retained mini-mental state examination and Montreal cognitive assessment scores on the domains of cognitive function and also instrumental activities of daily living in the domain of motion compared to the non-intervention group. Moreover, significant improvements in geriatric depression scales-15 and quality-of-life scales enabled the patients to maintain stable living compared to before the intervention. In addition, the intervention group showed a change in patterns that allowed them to voluntarily devote time to going out at the end of the study.

Research limitations/implications

This study was originally planned to compare the rates of transmission from MCI to dementia by tracking over five years (2016–2021). However, due to the impact of COVID-19, which began to spread around the world in 2020, further face-to-face visits and cognitive intervention became impossible. Thus, only half of the data in the existing plans were collected. Although it is difficult to present accurate results for the rate of transmission from MCI to dementia, the tendency was confirmed, indicating sufficient implications as an intervention.

Originality/value

This study was originally planned to compare the rates of transmission from MCI to dementia by tracking three years (2016–2019). The authors had studied for long-term effect.

Higher-Level Executive Functions in Healthy Elderly and Mild Cognitive Impairment: A Systematic Review

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. MCI exhibits cognitive, behavioral, psychological symptoms. The executive functions (EFs) are key functions for everyday life and physical and mental health and allow for the behavior to adapt to external changes. 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). 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. A total of 73 studies were identified. The results indicate that 65.8% of the studies confirm significant EFs alterations in MCI (56.8% planning, 50% reasoning, 100% problem solving, 71.4% fluid intelligence). These results seem to highlight a strong prevalence of higher-level executive functions deficits in MCI elderly than in healthy elderly.

Predictors of Cognitive Function in Community-Dwelling Older Adults by Age Group: Based on the 2017 National Survey of Older Korean Adults

Owing to a growing older adult population, dementia is emerging as an important health issue. Given that maintaining cognitive functions is crucial for the prevention of dementia, this study aimed to identify the predictors of cognitive function in community-dwelling older adults, through a secondary data analysis of the 2017 National Survey of Older Koreans. A total of 9836 participants were classified into three age groups—young-old (65–74 years), old-old (75–84 years), and oldest-old (≥85 years)—and were separately analyzed using multiple linear regression models. The final model explained 28.0%, 35.0%, and 37.0% of variance in cognitive function in the three age groups, respectively. The most potent predictors of cognitive function in the young-old were electronic device-based activities, instrumental activities of daily living (IADL), and nutrition management; the predictors for the old-old group were electronic device-based activities, IADL, and dementia screening, and those for the oldest-old group were frequency of contact with acquaintances, traveling, and religion. Thus, age group-specific interventions are needed to effectively promote cognitive function among older adults. Digital literacy education, use of community-based elderly welfare programs, opportunities for social interactions, and physical activities can help older adults in maintaining a functional status and muscle strengthening.

Neuropsychological Study in Patients with Spinal Cord Injuries

The present investigation was designed to determinate the nature, pattern, and extent of cognitive deficits in a group of participants with subacute and chronic spinal cord injury (SCI). Methods: A cross-sectional study was conducted in both patients with subacute and chronic SCI. Different cognitive functions were evaluated through a neuropsychological protocol designed for this purpose, taking into account the patient’s emotional state. Results: A total of 100 patients suffering a spinal cord injury were evaluated. There were no differences between the two groups when age, sex, level of education, and region of origin were studied. The chronic injured patients obtained lower scores in the neuropsychological evaluation protocol respective to the subacute injured patients. Conclusions: Subjects with chronic spinal cord injury presented a cognitive profile that differed greatly in the number of altered cognitive functions as well as in their magnitude from the subacute spinal cord injured patient profile. Moreover, cognitive dysfunction may be important beyond the end of the first stage of rehabilitation as it can affect an individual’s quality of life and possible integration in society.

[Prediction Models of Mild Cognitive Impairment Using the Korea Longitudinal Study of Ageing]

PURPOSE

The purpose of this study was to compare sociodemographic characteristics of a normal cognitive group and mild cognitive impairment group, and establish prediction models of Mild Cognitive Impairment (MCI).

METHODS

This study was a secondary data analysis research using data from "the 4th Korea Longitudinal Study of Ageing" of the Korea Employment Information Service. A total of 6,405 individuals, including 1,329 individuals with MCI and 5,076 individuals with normal cognitive abilities, were part of the study. Based on the panel survey items, the research used 28 variables. The methods of analysis included a χ²-test, logistic regression analysis, decision tree analysis, predicted error rate, and an ROC curve calculated using SPSS 23.0 and SAS 13.2.

RESULTS

In the MCI group, the mean age was 71.4 and 65.8% of the participants was women. There were statistically significant differences in gender, age, and education in both groups. Predictors of MCI determined by using a logistic regression analysis were gender, age, education, instrumental activity of daily living (IADL), perceived health status, participation group, cultural activities, and life satisfaction. Decision tree analysis of predictors of MCI identified education, age, life satisfaction, and IADL as predictors.

CONCLUSION

The accuracy of logistic regression model for MCI is slightly higher than that of decision tree model. The implementation of the prediction model for MCI established in this study may be utilized to identify middle-aged and elderly people with risks of MCI. Therefore, this study may contribute to the prevention and reduction of dementia.

Differential Diagnoses and Clinical Implications of Medication Nonadherence in Older Patients with Chronic Kidney Disease: A Review

Older adults with chronic kidney disease (CKD) often have many comorbidities, which requires them to take multiple medications. As the number of daily medications prescribed increases, the risk for polypharmacy increases. Understanding and improving medication adherence in this patient population is vital to avoiding the drug-related adverse events of polypharmacy. The primary objective of this review is to summarize the existing literature and to understand the factors leading to medication nonadherence in older patients with CKD. In this review, we discuss the prevalence of polypharmacy, the current lack of consensus on the incidence of medication nonadherence, the heterogeneity of assessing medication adherence, and the most common differential diagnoses for medication nonadherence in this population. Specifically, the most common differential diagnoses for medication nonadherence in older adults with CKD are (1) medication complexity; (2) cognitive impairment; (3) low health literacy; and (4) systems-based barriers. We provide tailored strategies to address these differential diagnoses and subsequently improve medication adherence. The clinical implications include deprescribing to decrease medication complexity and polypharmacy, utilizing a team-based approach to identify and support patients with cognitive impairment, enriching communication between health providers and patients with low health literacy, and improving health care access to address systems-based barriers. Further research is needed to determine the effects of addressing these differential diagnoses and medication adherence in older adults with CKD.

Executive functions in the elderly with mild cognitive impairment: a systematic review on motor and cognitive inhibition, conflict control and cognitive flexibility

Background: Mild Cognitive Impairment (MCI) is a syndrome characterised by mild cognitive decline, on one or more domains, but which does not compromise daily functions. Several studies have investigated the relationship between MCI and deficit in executive functions (EFs) but, unlike robust evidence in the mnestic domain, the nature of executive deficits in the MCI population remains uncertain.Objectives: This systematic review aims to evaluate EFs in patients with MCI, considering inhibition (motor and cognitive), conflict control and cognitive flexibility.Method: The databases used for the search were PUBMED, PsycINFO, PsycARTICLES and MEDLINE. Eligibility criteria: use of specific paradigms for EFs assessment ('Wisconsin Card Sorting Test', 'Stroop Task', 'Go/No-Go Task', 'Flanker Task'); age over 65, studies published in English. Exclusion criteria: presence of dementia; psychiatric disorders; stroke; cranial trauma; inclusion of participants with MCI in groups with healthy elderly or those with dementia.Results: Fifty-five studies were selected, namely: Stroop Task (N = 30), WCST (N = 14), Go/No-Go (N = 9), Flanker Task (N = 2). Results have shown in people with MCI deficits in all the EFs considered.Conclusions: The results of this review support the applicability of the four experimental tasks examined for the study of EFs in people with MCI. These paradigms are useful in research, diagnosis and therapeutic purposes, allowing obtaining an articulated EFs profile that can compromise the daily life in elderly. These EFs are not generally evaluated by standard assessment of MCI, but their evaluation can lead to a better knowledge of MCI and help in the diagnosis and treatment.

Cognitive stimulation program in mild cognitive impairment A randomized controlled trial

Non-pharmacological cognitive interventions in mild cognitive impairment have demonstrated promising results in preventing or delaying cognitive impairment and functional disability. Cognitive stimulation seems to improve and maintain cognitive and social activity.

Three months of multimodal training contributes to mobility and executive function in elderly individuals with mild cognitive impairment, but not in those with Alzheimer's disease: A randomized controlled trial

OBJECTIVE

To investigate the effects of a 12-week multimodal physical exercise program on global cognition, executive function and mobility in elderly people with mild cognitive impairment (MCI) or Alzheimer's disease (AD).

DESIGN

Randomized controlled trial (RCT) of two groups in parallel; single-blind.

METHOD

Patients were allocated to a control group (CG; n = 28 comprising MCI = 14 and AD = 14) and an exercise group (EG; n = 28 comprising MCI = 14 and AD = 14). The participants' physical and cognitive abilities were evaluated before and three months after the intervention. The training consisted of a 1-hour supervised program of multimodal physical exercises (aerobic, strength, balance and flexibility) of moderate intensity, delivered twice a week.

RESULTS

The independent t-test of the delta (Δ = post-intervention - pre-intervention) was used to compare the groups (CG x EG) for each diagnosis (MCI and AD). There was a significant difference only in the simple task mobility test (ΔCG: -0.18 ± 0.53; ΔEG: -1.05 ± 0.57; P =  0.03) and in the verbal fluency (ΔCG: -1.30 ± 2.49; ΔEG: 3.16 ± 1.72, P =  0.05) of the elderly with MCI, showing a beneficial effect of the multimodal exercise in this group.

CONCLUSION

Our findings indicate that a 12-week multimodal physical exercise program contributed to improvements in the mobility and executive function of elderly individuals with MCI, but not of those with AD. Although more RCTs are needed, physical exercise should be recommended to those in the early stages of neurocognitive disorder.

Functional Connectivity Changes Across the Spectrum of Subjective Cognitive Decline, Amnestic Mild Cognitive Impairment and Alzheimer's Disease

The abnormality occurs at molecular, cellular as well as network levels in patients with Alzheimer’s disease (AD) prior to diagnosis. Most previous connectivity studies were conducted at 1 out of 3 (local, meso and global) scales in subjects covering only part of the entire AD spectrum (subjective cognitive decline, SCD; amnestic mild cognitive impairment, aMCI; and then fully manifest AD). Data interpretation within the framework of disease progression is therefore difficult. The current study included 3 age- and sex-matched cohorts: SCD (n = 32), aMCI (n = 37) and fully-established AD (n = 30). A group of healthy elderly subjects (n = 40) were included as a normal control (NC). Network connectivity was examined at the local (degree centrality), meso [subgraph centrality (SC)], and global (eigenvector and page-rank centralities) levels. As compared to NC, SCD subjects had isolated decrease of SC in primary (somatomotor and visual) networks. aMCI subjects had decreased centralities at all three scales in associative (frontoparietal control, dorsal attention, limbic and default) networks. AD subjects had increased centrality at the global scale in all seven networks. There was a positive association between Montreal Cognitive Assessment (MoCA) scores and DC in the frontoparietal control network in SCD, a negative relationship between Mini-Mental State Examination (MMSE) scores and EC in the somatomotor network in AD. These findings suggest that the primary network is impaired as early as in SCD. Impairment in the associative network also starts at the local level at this stage and may contribute to the cognitive decline. As associative network impairment extends from local to meso and global scales in aMCI, compensatory mechanisms in the primary network are activated.

Loss of biliverdin reductase-A favors Tau hyper-phosphorylation in Alzheimer's disease

Hyper-active GSK-3β favors Tau phosphorylation during the progression of Alzheimer's disease (AD). Akt is one of the main kinases inhibiting GSK-3β and its activation occurs in response to neurotoxic stimuli including, i.e., oxidative stress. Biliverdin reductase-A (BVR-A) is a scaffold protein favoring the Akt-mediated inhibition of GSK-3β. Reduced BVR-A levels along with increased oxidative stress were observed early in the hippocampus of 3xTg-AD mice (at 6 months), thus suggesting that loss of BVR-A could be a limiting factor in the oxidative stress-induced Akt-mediated inhibition of GSK-3β in AD. We evaluated changes of BVR-A, Akt, GSK-3β, oxidative stress and Tau phosphorylation levels: (a) in brain from young (6-months) and old (12-months) 3xTg-AD mice; and (b) in post-mortem inferior parietal lobule (IPL) samples from amnestic mild cognitive impairment (MCI), from AD and from age-matched controls. Furthermore, similar analyses were performed in vitro in cells lacking BVR-A and treated with H₂O₂. Reduced BVR-A levels along with: (a) increased oxidative stress; (b) reduced GSK-3β inhibition; and (c) increased Tau Ser404 phosphorylation (target of GSK-3β activity) without changes of Akt activation in young mice, were observed. Similar findings were obtained in MCI, consistent with the notion that this is a molecular mechanism disrupted in humans. Interestingly, cells lacking BVR-A and treated with H₂O₂ showed reduced GSK-3β inhibition and increased Tau Ser404 phosphorylation, which resulted from a defect of Akt and GSK-3β physical interaction. Reduced levels of Akt/GSK-3β complex were confirmed in both young 3xTg-AD and MCI brain. We demonstrated that loss of BVR-A impairs the neuroprotective Akt-mediated inhibition of GSK-3β in response to oxidative stress, thus contributing to Tau hyper-phosphorylation in early stage AD. Such changes potential provide promising therapeutic targets for this devastating disorder.

Altered Whole-Brain Structural Covariance of the Hippocampal Subfields in Subcortical Vascular Mild Cognitive Impairment and Amnestic Mild Cognitive Impairment Patients

The hippocampus plays important roles in memory processing. However, the hippocampus is not a homogeneous structure, which consists of several subfields. The hippocampal subfields are differently affected by many neurodegenerative diseases, especially mild cognitive impairment (MCI). Amnestic mild cognitive impairment (aMCI) and subcortical vascular mild cognitive impairment (svMCI) are the two subtypes of MCI. aMCI is characterized by episodic memory loss, and svMCI is characterized by extensive white matter hyperintensities and multiple lacunar infarctions on magnetic resonance imaging. The primary cognitive impairment in svMCI is executive function, attention, and semantic memory. Some variations or disconnections within specific large-scale brain networks have been observed in aMCI and svMCI patients. The aim of this study was to investigate abnormalities in structural covariance networks (SCNs) between hippocampal subfields and the whole cerebral cortex in aMCI and svMCI patients, and whether these abnormalities are different between the two groups. Automated segmentation of hippocampal subfields was performed with FreeSurfer 5.3, and we selected five hippocampal subfields as the seeds of SCN analysis: CA1, CA2/3, CA4/dentate gyrus (DG), subiculum, and presubiculum. SCNs were constructed based on these hippocampal subfield seeds for each group. Significant correlations between hippocampal subfields, fusiform gyrus (FFG), and entorhinal cortex (ERC) in gray matter volume were found in each group. We also compared the differences in the strength of structural covariance between any two groups. In the aMCI group, compared to the normal controls (NC) group, we observed an increased association between the left CA1/CA4/DG/subiculum and the left temporal pole. Additionally, the hippocampal subfields (bilateral CA1, left CA2/3) significantly covaried with the orbitofrontal cortex in the svMCI group compared to the NC group. In the aMCI group compared to the svMCI group, we observed decreased association between hippocampal subfields and the right FFG, while we also observed an increased association between the bilateral subiculum/presubiculum and bilateral ERC. These findings provide new evidence that there is altered whole-brain structural covariance of the hippocampal subfields in svMCI and aMCI patients and provide insights to the pathological mechanisms of different MCI subtypes.

Impaired Functional Criticality of Human Brain during Alzheimer's Disease Progression

The progression of Alzheimer’s Disease (AD) has been proposed to comprise three stages, subjective cognitive decline (SCD), mild cognitive impairment (MCI), and AD. Was brain dynamics across the three stages smooth? Was there a critical transition? How could we characterize and study functional criticality of human brain? Based on dynamical characteristics of critical transition from nonlinear dynamics, we proposed a vertex-wise Index of Functional Criticality (vIFC) of fMRI time series in this study. Using 42 SCD, 67 amnestic MCI (aMCI), 34 AD patients as well as their age-, sex-, years of education-matched 54 NC, our new method vIFC successfully detected significant patient-normal differences for SCD and aMCI, as well as significant negative correlates of vIFC in the right middle temporal gyrus with total scores of Montreal Cognitive Assessment (MoCA) in SCD. In comparison, standard deviation of fMRI time series only detected significant differences between AD patients and normal controls. As an index of functional criticality of human brain derived from nonlinear dynamics, vIFC could serve as a sensitive neuroimaging marker for future studies; considering much more vIFC impairments in aMCI compared to SCD and AD, our study indicated aMCI as a critical stage across AD progression.

'It's definitely not Alzheimer's': Perceived benefits and drawbacks of a mild cognitive impairment diagnosis

OBJECTIVES

To understand the perceived benefits and drawbacks of a mild cognitive impairment (MCI) diagnosis from the perspective of those living with the label.

METHODS

Participants were included if they had recently (within 6 months) received a MCI diagnosis. We also recruited close family members to gain their perspectives. Each was interviewed separately with a semi-structured topic guide covering three areas: (1) experience of cognitive impairments and changes in the individual; (2) impact of cognitive impairment(s) on daily activities and social relationships; and (3) experience of the diagnosis process and living with the label. Transcribed interviews were stored in Nvivo^® . Grounded theory procedures of memo writing, open coding, constant comparison, and focused coding were used to derive conceptual themes.

RESULTS

Eighteen dyads were interviewed. The overarching themes surrounding diagnosis benefits and drawbacks were as follows: (1) emotional impact of the diagnosis; (2) practical benefits and limitations of the diagnosis, in terms of (a) understanding one's symptoms and (b) access to clinical support. Although participants were glad to have clinical support in place, they expressed frustration at the lack of clarity, and the lack of available treatments for MCI. Consequently, living with MCI can be characterized as an ambivalent experience.

CONCLUSION

As a clinical label, MCI appears to have little explanatory power for people living with cognitive difficulties. Work is needed to clarify how clinicians and patients communicate about MCI, and how people can be helped to live well with the label. Despite an emerging body of prognostic studies, people with MCI are likely to continue living with significant uncertainty. Statement of contribution What is already known on this subject? Mild cognitive impairment is a state of cognitive decline between normal cognitive ageing and dementia. This clinical category has been an important domain of academic debate over recent years. From a clinical perspective, diagnosing MCI is a helpful way to enable communication between health professionals, and a diagnosis can be important for patients in need of support and education. However, diagnosis can be fraught with difficulties, while patients have reported significant uncertainty about the label. This study aimed to examine the perceived benefits and drawbacks of receiving a MCI diagnosis. What does this study add? The emotional impact of a MCI diagnosis is complex and raised conflicting and fluctuating emotions in our participants' accounts - most notably worry and relief. Participants were glad to have clinical support available to call on; however, they were frustrated at the lack of 'treatments' available for MCI and were often anxious to slow any cognitive decline down Health psychologists will have an important role to play in understanding and improving clinical communication about MCI.

Classification of Alzheimer's disease using unsupervised diffusion component analysis

The goal of this study is automated discrimination between early stage Alzheimer's disease (AD) magnetic resonance imaging (MRI) and healthy MRI data. Unsupervised Diffusion Component Analysis, a novel approach based on the diffusion mapping framework, reduces data dimensionality and provides pattern recognition that can be used to distinguish AD brains from healthy brains. The new algorithm constructs coordinates as an extension of diffusion maps and generates efficient geometric representations of the complex structure of the MRI data. The key difference between our method and others used to classify and detect AD early in its course is our nonlinear and local network approach, which overcomes calibration differences among different scanners and centers collecting MRI data and solves the problem of individual variation in brain size and shape. In addition, our algorithm is completely automatic and unsupervised, which could potentially be a useful and practical tool for doctors to help identify AD patients.

Dysexecutive syndrome in amnesic mild cognitive impairment: a multicenter study

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Automated identification of dementia using medical imaging: a survey from a pattern classification perspective

In this review paper, we summarized the automated dementia identification algorithms in the literature from a pattern classification perspective. Since most of those algorithms consist of both feature extraction and classification, we provide a survey on three categories of feature extraction methods, including the voxel-, vertex- and ROI-based ones, and four categories of classifiers, including the linear discriminant analysis, Bayes classifiers, support vector machines, and artificial neural networks. We also compare the reported performance of many recently published dementia identification algorithms. Our comparison shows that many algorithms can differentiate the Alzheimer’s disease (AD) from elderly normal with a largely satisfying accuracy, whereas distinguishing the mild cognitive impairment from AD or elderly normal still remains a major challenge.

Hippocampal plasticity during the progression of Alzheimer's disease

Neuroplasticity involves molecular and structural changes in central nervous system (CNS) throughout life. The concept of neural organization allows for remodeling as a compensatory mechanism to the early pathobiology of Alzheimer's disease (AD) in an attempt to maintain brain function and cognition during the onset of dementia. The hippocampus, a crucial component of the medial temporal lobe memory circuit, is affected early in AD and displays synaptic and intraneuronal molecular remodeling against a pathological background of extracellular amyloid-beta (Aβ) deposition and intracellular neurofibrillary tangle (NFT) formation in the early stages of AD. Here we discuss human clinical pathological findings supporting the concept that the hippocampus is capable of neural plasticity during mild cognitive impairment (MCI), a prodromal stage of AD and early stage AD.

Synaptic change in the posterior cingulate gyrus in the progression of Alzheimer's disease

Mild cognitive impairment (MCI) is considered to be an early stage in the progression of Alzheimer's disease (AD) providing an opportunity to investigate brain pathogenesis prior to the onset of dementia. Neuroimaging studies have identified the posterior cingulate gyrus (PostC) as a cortical region affected early in the onset of AD. This association cortex is involved in a variety of different cognitive tasks and is intimately connected with the hippocampal/entorhinal cortex region, a component of the medial temporal memory circuit that displays early AD pathology. We quantified the total number of synapses in lamina 3 of the PostC using unbiased stereology coupled with electron microscopy from short postmortem autopsy tissue harvested from cases at different stage of AD progression. Individuals in the early stages of AD showed a significant decline in synaptic numbers compared to individuals with no cognitive impairment (NCI). Subjects with MCI exhibited synaptic numbers that were between the AD and NCI cohorts. Adjacent tissue was evaluated for changes in both pre and postsynaptic proteins levels. Individuals with MCI demonstrated a significant loss in presynaptic markers synapsin-1 and synaptophysin and postsynaptic markers PSD-95 and SAP-97. Levels of [3H]PiB binding was significantly increased in MCI and AD and correlated strongly with levels of synaptic proteins. All synaptic markers showed a significant association with Mini-Mental Status Examination scores. These results support the idea that the PostC synaptic function is affected during the prodromal stage of the disease and may underlie some of the early clinical sequelae associated with AD.

Instrumental activities of daily living performance and role satisfaction in people with and without mild cognitive impairment: a pilot project

OBJECTIVE

We investigated differences in observed performance of instrumental activities of daily living (IADLs) and self-reported satisfaction with social role performance between people with amnestic mild cognitive impairment (a-MCI) and age- and gender-matched control participants.

METHOD

We measured observed performance of 14 IADLs using the Independence, Safety, and Adequacy domains of the Performance Assessment of Self-Care Skills (PASS) and the Patient-Reported Outcomes Measurement Information Systems (PROMIS) to examine satisfaction with social role performance.

RESULTS

Total PASS scores were significantly lower in participants with a-MCI (median=40.6) than in control participants (median=44.2; p=.006). Adequacy scores were also significantly lower. No significant differences were found between groups on the PROMIS measures.

CONCLUSION

IADL differences between groups were related more to errors in adequacy than to safety and independence. Occupational therapy practitioners can play a key role in the diagnosis and treatment of subtle IADL deficits in people with MCI.

Multimodal prediction of conversion to Alzheimer's disease based on incomplete biomarkers

Background

This study investigates the prediction of mild cognitive impairment-to-Alzheimer's disease (MCI-to-AD) conversion based on extensive multimodal data with varying degrees of missing values.

Methods

Based on Alzheimer's Disease Neuroimaging Initiative data from MCI-patients including all available modalities, we predicted the conversion to AD within 3 years. Different ways of replacing missing data in combination with different classification algorithms are compared. The performance was evaluated on features prioritized by experts and automatically selected features.

Results

The conversion to AD could be predicted with a maximal accuracy of 73% using support vector machines and features chosen by experts. Among data modalities, neuropsychological, magnetic resonance imaging, and positron emission tomography data were most informative. The best single feature was the functional activities questionnaire.

Conclusion

Extensive multimodal and incomplete data can be adequately handled by a combination of missing data substitution, feature selection, and classification.

Reliability of a novel serious game using dual-task gait profiles to early characterize aMCI

Background: As the population of older adults is growing, the interest in a simple way to detect characterize amnestic mild cognitive impairment (aMCI), a prodromal stage of Alzheimer’s disease (AD), is becoming increasingly important. Serious game (SG) -based cognitive and motor performance profiles while performing everyday activities and dual-task walking (DTW) “motor signatures” are two very promising markers that can be detected in predementia states. We aim to compare the consistency, or conformity, of measurements made by a custom SG with DTW (NAV), a SG without DTW (DOT), neuropsychological measures and genotyping as markers for early detection of aMCI.

Methods: The study population included three groups: early AD (n = 86), aMCI (n = 65), and healthy control subjects (n = 76), who completed the custom SG tasks in three separate sessions over a 3-month period. Outcome measures were neuropsychological data across-domain and within-domain intra-individual variability (IIV) and DOT and NAV latency-based and accuracy-based IIV. IIV reflects a transient, within-person change in behavioral performance, either during different cognitive domains (across-domain) or within the same domain (within-domain). Test–retest reliability of the DOT and NAV markers were assessed using an intraclass correlation (ICC) analysis.

Results: Results indicated that performance data, such as the NAV latency-based and accuracy-based IIV, during the task displayed greater reliability across sessions compared to DOT. During the NAV task-engagement, the executive function, planning, and motor performance profiles exhibited moderate to good reliability (ICC = 0.6–0.8), while during DOT, executive function and spatial memory accuracy profiles exhibited fair to moderate reliability (ICC = 0.3–0.6). Additionally, reliability across tasks was more stable when three sessions were used in the ICC calculation relative to two sessions.

Discussion: Our findings suggest that “motor signature” data during the NAV tasks were a more reliable marker for early diagnosis of aMCI than DOT. This result accentuates the importance of utilizing motor performance data as a metric for aMCI populations where memory decline is often the behavioral outcome of interest. In conclusion, custom SG with DTW performance data provide an ecological and reliable approach for cognitive assessment across multiple sessions and thus can be used as a useful tool for tracking longitudinal change in observational and interventional studies on aMCI.

Coalition Against Major Diseases/European Medicines Agency biomarker qualification of hippocampal volume for enrichment of clinical trials in predementia stages of Alzheimer's disease

BACKGROUND

Regulatory qualification of a biomarker for a defined context of use provides scientifically robust assurances to sponsors and regulators that accelerate appropriate adoption of biomarkers into drug development.

METHODS

The Coalition Against Major Diseases submitted a dossier to the Scientific Advice Working Party of the European Medicines Agency requesting a qualification opinion on the use of hippocampal volume as a biomarker for enriching clinical trials in subjects with mild cognitive impairment, incorporating a scientific rationale, a literature review and a de novo analysis of Alzheimer's Disease Neuroimaging Initiative data.

RESULTS

The literature review and de novo analysis were consistent with the proposed context of use, and the Committee for Medicinal Products for Human Use released an opinion in November 2011.

CONCLUSIONS

We summarize the scientific rationale and the data that supported the first qualification of an imaging biomarker by the European Medicines Agency.

Factors that influence activities of daily living in the elderly with probable dementia

The purpose of this study was to identify the factors that influence activities of daily living (ADL) in the elderly with probable dementia. The participants were 152 older adults who voluntarily visited a hospital to participate in a national dementia free screening programme. General characteristics, health-related characteristics, ADL, Mini-Mental State Examination Korean Consortium (MMSE-KC) and the Geriatric Depression Scale (GDS) score were evaluated in this study. The data were analysed using independent t-tests, Pearson's correlation and stepwise multiple regression. The ADL score of the participants was 14.3, and 88.2% of the participants were severe cognitive disorder. ADL scores were positively related with MMSE-KC scores (r = 0.35, P < 0.001) and negatively with GDS scores (r = -0.20, P = 0.014). Factors that influenced ADL were faecal and urinary incontinence, regularity of exercise, MMSE-KC score and stroke history; these five variables explained 30.8% of the ADL score for the elderly with probable dementia. Multidisciplinary interventions are essential to improve the ADL and prevent deterioration of cognitive function in elderly patients with probable dementia.

Grey-matter volume as a potential feature for the classification of Alzheimer's disease and mild cognitive impairment: an exploratory study

Specific patterns of brain atrophy may be helpful in the diagnosis of Alzheimer's disease (AD). In the present study, we set out to evaluate the utility of grey-matter volume in the classification of AD and amnestic mild cognitive impairment (aMCI) compared to normal control (NC) individuals. Voxel-based morphometric analyses were performed on structural MRIs from 35 AD patients, 27 aMCI patients, and 27 NC participants. A two-sample two-tailed t-test was computed between the NC and AD groups to create a map of abnormal grey matter in AD. The brain areas with significant differences were extracted as regions of interest (ROIs), and the grey-matter volumes in the ROIs of the aMCI patients were included to evaluate the patterns of change across different disease severities. Next, correlation analyses between the grey-matter volumes in the ROIs and all clinical variables were performed in aMCI and AD patients to determine whether they varied with disease progression. The results revealed significantly decreased grey matter in the bilateral hippocampus/parahippocampus, the bilateral superior/middle temporal gyri, and the right precuneus in AD patients. The grey-matter volumes were positively correlated with clinical variables. Finally, we performed exploratory linear discriminative analyses to assess the classifying capacity of grey-matter volumes in the bilateral hippocampus and parahippocampus among AD, aMCI, and NC. Leave-one-out cross-validation analyses demonstrated that grey-matter volumes in hippocampus and parahippocampus accurately distinguished AD from NC. These findings indicate that grey-matter volumes are useful in the classification of AD.

Can a novel computerized cognitive screening test provide additional information for early detection of Alzheimer's disease?

BACKGROUND

Virtual reality testing of everyday activities is a novel type of computerized assessment that measures cognitive, executive, and motor performance as a screening tool for early dementia. This study used a virtual reality day-out task (VR-DOT) environment to evaluate its predictive value in patients with mild cognitive impairment (MCI).

METHODS

One hundred thirty-four patients with MCI were selected and compared with 75 healthy control subjects. Participants received an initial assessment that included VR-DOT, a neuropsychological evaluation, magnetic resonance imaging (MRI) scan, and event-related potentials (ERPs). After 12 months, participants were assessed again with MRI, ERP, VR-DOT, and neuropsychological tests.

RESULTS

At the end of the study, we differentiated two subgroups of patients with MCI according to their clinical evolution from baseline to follow-up: 56 MCI progressors and 78 MCI nonprogressors. VR-DOT performance profiles correlated strongly with existing predictive biomarkers, especially the ERP and MRI biomarkers of cortical thickness.

CONCLUSIONS

Compared with ERP, MRI, or neuropsychological tests alone, the VR-DOT could provide additional predictive information in a low-cost, computerized, and noninvasive way.

Hierarchical interactions model for predicting Mild Cognitive Impairment (MCI) to Alzheimer's Disease (AD) conversion

Identifying patients with Mild Cognitive Impairment (MCI) who are likely to convert to dementia has recently attracted increasing attention in Alzheimer's disease (AD) research. An accurate prediction of conversion from MCI to AD can aid clinicians to initiate treatments at early stage and monitor their effectiveness. However, existing prediction systems based on the original biosignatures are not satisfactory. In this paper, we propose to fit the prediction models using pairwise biosignature interactions, thus capturing higher-order relationship among biosignatures. Specifically, we employ hierarchical constraints and sparsity regularization to prune the high-dimensional input features. Based on the significant biosignatures and underlying interactions identified, we build classifiers to predict the conversion probability based on the selected features. We further analyze the underlying interaction effects of different biosignatures based on the so-called stable expectation scores. We have used 293 MCI subjects from Alzheimer's Disease Neuroimaging Initiative (ADNI) database that have MRI measurements at the baseline to evaluate the effectiveness of the proposed method. Our proposed method achieves better classification performance than state-of-the-art methods. Moreover, we discover several significant interactions predictive of MCI-to-AD conversion. These results shed light on improving the prediction performance using interaction features.

Rate of conversion from prodromal Alzheimer's disease to Alzheimer's dementia: a systematic review of the literature

Background

The purpose of this study was to summarize published estimates for conversion from mild cognitive impairment or amnestic mild cognitive impairment to Alzheimer's dementia. We carried out a systematic review of English language publications to identify cohort studies published since January 2006 that reported the risk or rate of conversion.

Summary

Thirty-two cohort studies were identified, of which 14 reported annualized conversion rates (ACRs). Conversions over 1 year ranged from 10.2 to 33.6% (5 studies, median: 19.0%), and over 2 years from 9.8 to 36.3% (7 studies, median: 18.6%). ACRs ranged from 7.5 to 16.5% (7 studies, median: 11.0%) per person-year for studies recruiting from clinics, and from 5.4 to 11.5% (7 studies, median: 7.1%) for community samples.

Key Message

Extensive variation was observed in conversion rates due to the population sampled, diagnostic criteria, and duration, and because many studies did not account for loss to follow-up.

Oestrogen receptor polymorphisms are an associated risk factor for mild cognitive impairment and Alzheimer disease in women APOE {varepsilon}4 carriers: a case-control study

OBJECTIVES

Examine the role of single nucleotide polymorphisms (SNPs) in the oestrogen receptor (ER) genes: rs9340799, rs2234693, rs2228480 (in the ESR1 gene) and rs4986938 (in the ESR2 gene) as a risk factor for amnesic mild cognitive impairment (MCIa) and Alzheimer's disease (AD) and its possible association with the apolipoprotein E (APOE) gene.

DESIGN

We have investigated the independent and combined association of different alleles of the oestrogen receptor genes and APOE*ε4 allele with cognitive impairment using a case-control design.

SETTING

Participants were prospectively recruited from the neurology departments of several Basque Country hospitals.

PARTICIPANTS

This study comprised 816 Caucasian participants who were aged 50 years and older: 204 MCIa, 350 sporadic patients with AD and 262 healthy controls.

PRIMARY AND SECONDARY OUTCOME MEASURES

Clinical criteria and neuropsychological tests were used to establish the diagnostic groups (MCIa, AD and healthy controls). A dichotomous variable was used for each allele and genotype and the association with MCIa and AD was established using Logistic Regression Models.

RESULTS

Neither alleles nor genotypes of SNPs rs9340799, rs2234693, rs2228480 and rs4986938 of oestrogen receptor genes (ESR1 and ESR2) are independently associated with the risk of MCIa or AD. However, the genetic profile created with the combination of the less represented alleles of these SNPs (expressed as XPAA) was associated with an increased risk for MCIa (OR=3.30, 95% CI 1.28 to 8.54, p=0.014) and AD (OR=5.16, 95% CI 2.19 to 12.14, p<0.001) in women APOE*ε4 allele carriers.

CONCLUSIONS

The less represented alleles of SNPs studied are associated with MCIa and AD in APOE*E4 carriers. In particular, the genetic profile created with the less represented alleles of ESR1 and ESR2 SNPs are associated with an increased risk for MCIa and AD in women APOEε4 allele carriers.

Disease progression model in subjects with mild cognitive impairment from the Alzheimer's disease neuroimaging initiative: CSF biomarkers predict population subtypes

AIM

The objective is to develop a semi-mechanistic disease progression model for mild cognitive impairment (MCI) subjects. The model aims to describe the longitudinal progression of ADAS-cog scores from the Alzheimer's disease neuroimaging initiative trial that had data from 198 MCI subjects with cerebrospinal fluid (CSF) information who were followed for 3 years.

METHOD

Various covariates were tested on disease progression parameters and these variables fell into six categories: imaging volumetrics, biochemical, genetic, demographic, cognitive tests and CSF biomarkers.

RESULTS

CSF biomarkers were associated with both baseline disease score and disease progression rate in subjects with MCI. Baseline disease score was also correlated with atrophy measured using hippocampal volume. Progression rate was also predicted by executive functioning as measured by the Trail B-test.

CONCLUSION

CSF biomarkers have the ability to discriminate MCI subjects into sub-populations that exhibit markedly different rates of disease progression on the ADAS-cog scale. These biomarkers can therefore be utilized for designing clinical trials enriched with subjects that carry the underlying disease pathology.

Neural correlates of saccadic inhibition in healthy elderly and patients with amnestic mild cognitive impairment

Performance on tasks that require saccadic inhibition declines with age and altered inhibitory functioning has also been reported in patients with Alzheimer's disease. Although mild cognitive impairment (MCI) is assumed to be a high-risk factor for conversion to AD, little is known about changes in saccadic inhibition and its neural correlates in this condition. Our study determined whether the neural activation associated with saccadic inhibition is altered in persons with amnestic mild cognitive impairment (aMCI). Functional magnetic resonance imaging (fMRI) revealed decreased activation in parietal lobe in healthy elderly persons compared to young persons and decreased activation in frontal eye fields in aMCI patients compared to healthy elderly persons during the execution of anti-saccades. These results illustrate that the decline in inhibitory functions is associated with impaired frontal activation in aMCI. This alteration in function might reflect early manifestations of AD and provide new insights in the neural activation changes that occur in pathological ageing.

Changes over time in memory, processing speed and clock drawing tests help to discriminate between vascular cognitive impairment, mild cognitive impairment and Alzheimer's disease

Measures of cognitive change over time may help to better discriminate between mild cognitive impairment, Alzheimer's disease and vascular cognitive impairment than single assessments. Our hypothesis was that performance in processing speed and executive function would decline with mild cognitive impairment and Alzheimer's disease. Subjects included 36 controls, 18 cases with mild cognitive impairment, eight with vascular cognitive impairment and 24 with Alzheimer's disease who were tested on a cognitive battery at two episodes with a 12-month interval. Changes in performance were determined for each group with paired means tests. Controls improved in pattern comparison speed and the CLOX, a clock-drawing task to detect dysexecutive function. Those with vascular cognitive impairment declined in letter comparison speed, but improved in paragraph recall. Alzheimer's disease patients declined in CLOX and the Hopkins Verbal Learning Test. The mild cognitive impairment group showed no significant changes. Alzheimer's disease patients on treatment declined in Hopkins Verbal Learning Test, while those without treatment declined in The Placing Test and CLOX. Processing speed decline may be a marker of cerebrovascular disease, while decline in memory and executive function was more evident with Alzheimer's disease.

Diagnosing Mild Cognitive Impairment (MCI) in clinical trials: a systematic review

OBJECTIVE

To describe how criteria for amnestic Mild Cognitive Impairment (aMCI) have been operationalised in randomised controlled clinical trials (RCTs).

DESIGN

Systematic review.

INFORMATION SOURCES

EMBASE, PubMed and PSYCHInfo were searched from their inception to February 2012. Electronic clinical trial registries were also searched (February 2012).

STUDY SELECTION

RCTs were included where participant selection was made using Petersen et al-defined aMCI. There was no restriction on intervention type or the outcome tested.

DATA EXTRACTION

For each trial, we extracted information on study design, demographics, exclusion criteria and the operationalisation strategy for the five aMCI diagnostic criteria including: (1) memory complaint, (2) normal general cognitive function, (3) memory impairment, (4) no functional impairment and (5) no dementia.

RESULTS

223 articles and 278 registered trials were reviewed, of which 22 met inclusion criteria. Various methods were applied for operationalising aMCI criteria resulting in variability in participant selection. Memory complaint and assessment of general cognitive function were the most consistently measured criteria. There was large heterogeneity in the neuropsychological methods used to determine memory impairment. It was not possible to assess the impact of these differences on case selection accuracy for dementia prediction. Further limitations include selective and unclear reporting of how each of the criteria was measured.

CONCLUSIONS

The results highlight the urgent need for a standardised approach to map aMCI. Lack of uniformity in clinical diagnosis, however, is not exclusively a problem for MCI but also for other clinical states such as dementia including Alzheimer's disease, Lewy Body, frontotemporal or vascular dementia. Defining a uniform approach to MCI classification, or indeed for any classification concept within the field of dementia, should be a priority if further trials are to be undertaken in the older aged population based on these concepts.

Huperzine A for mild cognitive impairment

BACKGROUND

Mild cognitive impairment (MCI) has been proposed as a condition of intermediate symptomatology between the cognitive changes of ageing and fully developed symptoms of dementia. Treatment in the stages of MCI may delay the deterioration of cognitive impairment and delay the progression to dementia. Currently, the treatments for Alzheimer's disease have been focused on increasing acetylcholine levels in the brain. However, these drugs have not been proven to be effective for MCI and have numerous side effects. Huperzine A may have some beneficial effects in MCI.

OBJECTIVES

To assess the clinical efficacy and safety of huperzine A for the treatment of patients with MCI.

SEARCH METHODS

We searched ALOIS: the Cochrane Dementia and Cognitive Improvement Group's Specialized Register on 23 May 2011 using the terms: huperzine, ayapin, scoparon. ALOIS contains records of clinical trials identified from monthly searches of a number of major healthcare databases, numerous trial registries and grey literature sources. Additional searches were also performed separately in MEDLINE, EMBASE, PsycINFO, LILACS, clinicalTrials.gov, the ICTRP (WHO portal), CENTRAL (The Cochrane Library) and Web of Science with Conference Proceedings.The following Chinese databases were searched: The Chinese Biomedical Database, VIP Chinese Science and Technique Journals Database, China National Knowledge Infrastructure and The Chinese Clinical Trials Register. In addition, we handsearched 20 Chinese traditional medicine journals from between 1970 and 1989.

SELECTION CRITERIA

Randomised, parallel-group, placebo-controlled trials comparing huperzine A with placebo in patients with MCI were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for their eligibility for inclusion.

MAIN RESULTS

No eligible trials were identified. In the absence of any suitable randomised placebo-controlled trials in this area, we were unable to perform a meta-analysis.

AUTHORS' CONCLUSIONS

The currently available evidence is insufficient to assess the potential for huperzine A in the treatment of MCI. Randomised double-blind placebo-controlled trials are needed.

Unbiased tensor-based morphometry: improved robustness and sample size estimates for Alzheimer's disease clinical trials

Various neuroimaging measures are being evaluated for tracking Alzheimer's disease (AD) progression in therapeutic trials, including measures of structural brain change based on repeated scanning of patients with magnetic resonance imaging (MRI). Methods to compute brain change must be robust to scan quality. Biases may arise if any scans are thrown out, as this can lead to the true changes being overestimated or underestimated. Here we analyzed the full MRI dataset from the first phase of Alzheimer's Disease Neuroimaging Initiative (ADNI-1) from the first phase of Alzheimer's Disease Neuroimaging Initiative (ADNI-1) and assessed several sources of bias that can arise when tracking brain changes with structural brain imaging methods, as part of a pipeline for tensor-based morphometry (TBM). In all healthy subjects who completed MRI scanning at screening, 6, 12, and 24months, brain atrophy was essentially linear with no detectable bias in longitudinal measures. In power analyses for clinical trials based on these change measures, only 39AD patients and 95 mild cognitive impairment (MCI) subjects were needed for a 24-month trial to detect a 25% reduction in the average rate of change using a two-sided test (α=0.05, power=80%). Further sample size reductions were achieved by stratifying the data into Apolipoprotein E (ApoE) ε4 carriers versus non-carriers. We show how selective data exclusion affects sample size estimates, motivating an objective comparison of different analysis techniques based on statistical power and robustness. TBM is an unbiased, robust, high-throughput imaging surrogate marker for large, multi-site neuroimaging studies and clinical trials of AD and MCI.

Four-year outcome of mild cognitive impairment: the contribution of executive dysfunction

OBJECTIVE

The contribution of executive cognition (EC) to the prediction of incident dementia remains unclear. This prospective study examined the predictive value of EC for subsequent cognitive decline in persons with mild cognitive impairment (MCI) over a 4-year period.

METHOD

One hundred forty-one persons with MCI (amnestic and nonamnestic, single- and multiple-domain) received a baseline and two biennial follow-up assessments. Eighteen tests, assessing six different aspects of EC, were administered at baseline and at 2-year follow-up, together with screening cognitive and daily functioning measures. Longitudinal logistic regression models and generalized estimating equations (GEE) were used to examine whether EC could predict progression to a Clinical Dementia Rating Scale (CDR; C. P. Hughes, L. Berg, W. L. Danziger, L. A. Coben, & R. L. Martin, 1982, A new clinical scale for the staging of dementia, British Journal of Psychiatry, Vol. 140, pp. 566-572) score of 1 or more over the 4-year period, first at the univariate level and then in the context of demographic and clinical characteristics, daily functioning measures, and other neurocognitive factors.

RESULTS

Over the 4-year period, 56% of MCI patients remained stable, 35% progressed to CDR ≥ 1, and 8% reverted to normal (CDR = 0). Amnestic MCI subtypes were not associated with higher rates of progression to dementia, whereas subtypes with multiple impairments were so associated. Eight out of the 18 EC measures, including all three measures assessing inhibition of prepotent responses, predicted MCI outcome at the univariate level. However, the multivariate GEE model indicated that age, daily functioning, and overall cognitive functioning best predicted progression to dementia.

CONCLUSION

Measures of EC (i.e., inhibitory control) are associated with MCI outcome. However, age and global measures of cognitive and functional impairment are better predictors of incident dementia.