The nature and staging of attention dysfunction in early (minimal and mild) Alzheimer's disease: relationship to episodic and semantic memory impairment

ZORA robot to assist a caregiver in prospective memory tasks: A preliminary study

The objective of the present study was to evaluate the interest of an assistance robot to help caregivers manage the activities of daily living of institutionalized elderly people with Alzheimer's disease. Twenty-three institutionalized persons (60% women; average age 89; average MMSE score of 20.8) with Alzheimer Disease (AD) were recruited and invited to participate in prospective memory exercise sessions, conducted either by a caregiver or by a robot (assisted by a caregiver). They were divided into two groups equivalent in age, level of education and MMSE score. In addition, the sessions were recorded in order to compare the interaction behaviors of the 2 groups, using a validated observation grid. The results showed that: 1) prospective memory tasks are better performed when offered by the caregiver; 2) when strong help linked to the recovery index is provided to perform the tasks, the robot or caregiver no longer show significant differences; 3) participants interact more with the caregiver than with the robot. Our results confirm that the use of companion robots is a promising way to help caregivers manage the daily activities of people with Alzheimer's. However, to optimize this assistance, further investigations should be conducted to improve the fluidity of interactions between the patient and the robot.

Understanding the human conflict processing network: A review of the literature on direct neural recordings during performance of a modified stroop task

The Stroop Task is a well-known neuropsychological task developed to investigate conflict processing in the human brain. Our group has utilized direct intracranial neural recordings in various brain regions during performance of a modified color-word Stroop Task to gain a mechanistic understanding of non-emotional human conflict processing. The purpose of this review article is to: 1) synthesize our own studies into a model of human conflict processing, 2) review the current literature on the Stroop Task and other conflict tasks to put our research in context, and 3) describe how these studies define a network in conflict processing. The figures presented are reprinted from our prior publications and key publications referenced in the manuscript. We summarize all studies to date that employ invasive intracranial recordings in humans during performance of conflict-inducing tasks. For our own studies, we analyzed local field potentials (LFPs) from patients with implanted stereotactic electroencephalography (SEEG) electrodes, and we observed intracortical oscillation patterns as well as intercortical temporal relationships in the hippocampus, amygdala, and orbitofrontal cortex (OFC) during the cue-processing phase of a modified Stroop Task. Our findings suggest that non-emotional human conflict processing involves modulation across multiple frequency bands within and between brain structures.

The assessment of executive function abilities in healthy and neurodegenerative aging-A selective literature review

Numerous studies have examined executive function (EF) abilities in cognitively healthy older adults and those living with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Currently, there are no standard accepted protocols for testing specific EFs; thus, researchers have used their preferred tool, which leads to variability in assessments of decline in a particular ability across studies. Therefore, there is a need for guidance as to the most sensitive tests for assessing EF decline. A search of the most current literature published between 2000 and 2022 on EF studies assessing cognitively healthy older adults and individuals living with MCI and AD was conducted using PubMed/Medline, PsycINFO, Embase, Web of Science, and Google Scholar. Emphasis was placed on the EF's dual-tasking, inhibition, shifting or switching, and working memory updating. Many tasks and their outcomes were reviewed. Of particular importance was the difference in outcomes for tasks applied to the same group of participants. These various EF assessment tools demonstrate differences in effectively identifying decline in EF ability due to the aging process and neurodegenerative conditions, such as MCI and AD. This review identifies various factors to consider in using particular EF tasks in particular populations, including task demand and stimuli factors, and also when comparing differing results across studies.

Alterations of Audiovisual Integration in Alzheimer's Disease

Audiovisual integration is a vital information process involved in cognition and is closely correlated with aging and Alzheimer's disease (AD). In this review, we evaluated the altered audiovisual integrative behavioral symptoms in AD. We further analyzed the relationships between AD pathologies and audiovisual integration alterations bidirectionally and suggested the possible mechanisms of audiovisual integration alterations underlying AD, including the imbalance between energy demand and supply, activity-dependent degeneration, disrupted brain networks, and cognitive resource overloading. Then, based on the clinical characteristics including electrophysiological and imaging data related to audiovisual integration, we emphasized the value of audiovisual integration alterations as potential biomarkers for the early diagnosis and progression of AD. We also highlighted that treatments targeted audiovisual integration contributed to widespread pathological improvements in AD animal models and cognitive improvements in AD patients. Moreover, investigation into audiovisual integration alterations in AD also provided new insights and comprehension about sensory information processes.

Deep Learning of Speech Data for Early Detection of Alzheimer's Disease in the Elderly

BACKGROUND

Alzheimer's disease (AD) is the most common form of dementia, which makes the lives of patients and their families difficult for various reasons. Therefore, early detection of AD is crucial to alleviating the symptoms through medication and treatment.

OBJECTIVE

Given that AD strongly induces language disorders, this study aims to detect AD rapidly by analyzing the language characteristics.

MATERIALS AND METHODS

The mini-mental state examination for dementia screening (MMSE-DS), which is most commonly used in South Korean public health centers, is used to obtain negative answers based on the questionnaire. Among the acquired voices, significant questionnaires and answers are selected and converted into mel-frequency cepstral coefficient (MFCC)-based spectrogram images. After accumulating the significant answers, validated data augmentation was achieved using the Densenet121 model. Five deep learning models, Inception v3, VGG19, Xception, Resnet50, and Densenet121, were used to train and confirm the results.

RESULTS

Considering the amount of data, the results of the five-fold cross-validation are more significant than those of the hold-out method. Densenet121 exhibits a sensitivity of 0.9550, a specificity of 0.8333, and an accuracy of 0.9000 in a five-fold cross-validation to separate AD patients from the control group.

CONCLUSIONS

The potential for remote health care can be increased by simplifying the AD screening process. Furthermore, by facilitating remote health care, the proposed method can enhance the accessibility of AD screening and increase the rate of early AD detection.

Diminished activation of excitatory neurons in the prelimbic cortex leads to impaired working memory capacity in mice

BACKGROUND

Working memory capacity impairment is an early sign of Alzheimer's disease, but the underlying mechanisms remain unclear. Clarifying how working memory capacity is affected will help us better understand the pathological mechanism of Alzheimer's disease. We used the olfactory working memory capacity paradigm to evaluate memory capacity in 3-month-old 5XFAD (an animal model of Alzheimer's disease) mice. Immunofluorescence staining of the prefrontal cortex was performed to detect the number of FOS-positive neurons, calmodulin-dependent protein kinase II-positive neurons, and glutamate decarboxylase-positive neurons in the prelimbic cortex and infralimbic cortex. A chemogenetic method was then used to modulate the inhibition and activation of excitatory neurons in the prelimbic cortex of wild-type and 5XFAD mice and to measure the memory capacity of mice.

RESULTS

Working memory capacity was significantly diminished in 5XFAD mice compared to littermate wild-type mice. Neuronal activation of the prelimbic cortex, but not the infralimbic cortex, was attenuated in 5XFAD mice performing the olfactory working memory capacity task. Subsequently, the FOS-positive neurons were co-localized with both calmodulin-dependent protein kinase II-positive neurons and glutamate decarboxylase-positive neurons. The results showed that the activation of excitatory neurons in the prelimbic cortex was correlated with working memory capacity in mice. Our results further demonstrate that the chemogenetic inhibition of prelimbic cortex excitatory neurons resulted in reduced working memory capacity in wild-type mice, while the chemogenetic activation of prelimbic cortex excitatory neurons improved the working memory capacity of 5XFAD mice.

CONCLUSION

The diminished activation of prelimbic cortex excitatory neurons in 5XFAD mice during task performance is associated with reduced working memory capacity, and activation modulation of excitatory neurons by chemogenetic methods can improve memory capacity impairment in 5XFAD mice. These findings may provide a new direction for exploring Alzheimer's disease therapeutic approaches.

Effects of Tai Chi combined with tDCS on cognitive function in patients with MCI: a randomized controlled trial

Background

Mild cognitive impairment (MCI) is a critical stage of dementia. Previous reviews have suggested that physical exercise combined with non-invasive brain stimulation is more beneficial for improving cognitive function. However, no targeted studies have confirmed the effect of Tai Chi combined with transcranial direct current stimulation (tDCS) on the improvement of cognitive function in patients with MCI. Thus, this randomized trial was conducted to assess the effect of Tai Chi combined with tDCS on the cognitive performance of patients with MCI.

Methods

From April 2018 to February 2020, a randomized, single-blind clinical trial was conducted, involving 180 participants with MCI who were divided into four intervention groups: Tai Chi combined with tDCS (TCT), Tai Chi combined with sham tDCS (TCS), walking combined with tDCS (WAT), and walking combined with sham tDCS (WAS). All participants were assessed at baseline and 12 weeks for global cognitive function, memory, attention, and executive function.

Results

At baseline, there were no significant differences in age, gender, education duration, body mass index, or the Baker Depression Inventory among the four groups (P ≥ 0.05). After 12 weeks of intervention, the TCT group showed greater improvements in MOCA scores, memory quotient scores, and digit-symbol coding task reaction time compared to the TCS, WAS, and WAT groups (P < 0.05). The TCT group also had a shorter Stroop test color reaction time compared to the WAS and WAT groups (P < 0.05), a higher increase in Auditory Verbal Learning Test-immediate recall than the TCS and WAT groups (P < 0.05), a shorter visual reaction time than the TCS group (P < 0.05), and a shorter sustained attention time compared to the WAT group (P < 0.05).

Conclusion

Tai Chi combined with tDCS effectively improves global cognitive performance, memory, execution function, and attention in patients with MCI. These findings suggest the potential clinical use of Tai Chi combined with tDCS as a physical exercise combined with a non-invasive brain stimulation intervention to improve cognitive function in older adults with MCI.

Clinical trial registration

ChiCTR1800015629.

Longitudinal assessment of cognitive function in the APPswe/PS1dE9 mouse model of Alzheimer's-related beta-amyloidosis

Preclinical models of Alzheimer's disease (AD)-related cognitive decline can be useful for developing therapeutics. The current study longitudinally assessed short-term memory, using a delayed matching-to-position (DMTP) task, and attention, using a 3-choice serial reaction time (3CSRT) task, from approximately 18 weeks of age through death or 72 weeks of age in APPswe/PS1dE9 mice, a widely used mouse model of AD-related amyloidosis. Both transgenic (Tg) and non-Tg mice exhibited improvements in DMTP accuracy over time. Breaks in testing reduced DMTP accuracy but accuracy values quickly recovered in both Tg and non-Tg mice. Both Tg and non-Tg mice exhibited high accuracy in the 3CSRT task with breaks in testing briefly reducing accuracy values equivalently in the 2 genotypes. The current results raise the possibility that deficits in Tg APPswe/PS1dE9 mice involve impairments in learning rather than declines in established performances. A better understanding of the factors that determine whether deficits develop will be useful for designing evaluations of potential pharmacotherapeutics and may reveal interventions for clinical application.

Comprehensive review of task-based neuroimaging studies of cognitive deficits in Alzheimer's disease using electrophysiological methods

With an aging population, cognitive decline and neurodegenerative disorders are an emerging public health crises with enormous, yet still under-recognized burdens. Alzheimer's disease (AD) is the most common type of dementia, and the number of cases is expected to dramatically rise in the upcoming decades. Substantial efforts have been placed into understanding the disease. One of the primary avenues of research is neuroimaging, and while positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) are most common, crucial recent advancements in electrophysiological methods such as magnetoencephalography (MEG) and electroencephalography (EEG) have provided novel insight into the aberrant neural dynamics at play in AD pathology. In this review, we outline task-based M/EEG studies published since 2010 using paradigms probing the cognitive domains most affected by AD, including memory, attention, and executive functioning. Furthermore, we provide important recommendations for adapting cognitive tasks for optimal use in this population and adjusting recruitment efforts to improve and expand future neuroimaging work.

Functional and structural alterations of dorsal attention network in preclinical and early-stage Alzheimer's disease

OBJECTIVES

Subjective cognitive decline (SCD) and amnestic mild cognitive impairment (aMCI) are known as the preclinical and early stage of Alzheimer's disease (AD). The dorsal attention network (DAN) is mainly responsible for the "top-down" attention process. However, previous studies mainly focused on single functional modality and limited structure. This study aimed to investigate the multimodal alterations of DAN in SCD and aMCI to assess their diagnostic value in preclinical and early-stage AD.

METHODS

Resting-state functional magnetic resonance imaging (MRI) was carried out to measure the fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), and functional connectivity (FC). Structural MRI was used to calculate the gray matter volume (GMV) and cortical thickness. Moreover, receiver-operating characteristic (ROC) analysis was used to distinguish these alterations in SCD and aMCI.

RESULTS

The SCD and aMCI groups showed both decreased ReHo in the right middle temporal gyrus (MTG) and decreased GMV compared to healthy controls (HCs). Especially in the SCD group, there were increased fALFF and increased ReHo in the left inferior occipital gyrus (IOG), decreased fALFF and increased FC in the left inferior parietal lobule (IPL), and reduced cortical thickness in the right inferior temporal gyrus (ITG). Furthermore, functional and structural alterations in the SCD and aMCI groups were closely related to episodic memory (EM), executive function (EF), and information processing speed (IPS). The combination of multiple indicators of DAN had a high accuracy in differentiating clinical stages.

CONCLUSIONS

Our current study demonstrated functional and structural alterations of DAN in SCD and aMCI, especially in the MTG, IPL, and SPL. Furthermore, cognitive performance was closely related to these significant alterations. Our study further suggested that the combined multiple indicators of DAN could be acted as the latent neuroimaging markers of preclinical and early-stage AD for their high diagnostic value.

Mitochondria: how eminent in ageing and neurodegenerative disorders?

Numerous factors are implicated in the onset and progression of ageing and neurodegenerative disorders, with defects in cell energy supply and free radicals regulation designated as being the main functions of mitochondria and highly accentuated in plentiful studies. Hence, analysing the role of mitochondria as one of the main factors implicated in these disorders could undoubtedly come in handy with respect to disease prevention and treatment. In this review, first, we will explore how mitochondria account for neurodegenerative disorders and ageing and later will draw the various pathways contributing to mitochondrial dysfunction in their distinct way. Also, we will discuss the deviation-countering mechanisms, particularly mitophagy, a subset of autophagy known as a much larger cellular defence mechanism and regulatory system, along with its potential therapeutic effects. Last but not least, we will be highlighting the mitochondrial transfer experiments with animal models of neurodegenerative disorders.

P. edulis Extract Protects Against Amyloid-β Toxicity in Alzheimer's Disease Models Through Maintenance of Mitochondrial Homeostasis via the FOXO3/DAF-16 Pathway

Alzheimer's disease (AD) is a common and devastating disease characterized by pathological aggregations of beta-amyloid (Aβ) plaques extracellularly, and Tau tangles intracellularly. While our understandings of the aetiologies of AD have greatly expanded over the decades, there is no drug available to stop disease progression. Here, we demonstrate the potential of Passiflora edulis (P. edulis) pericarp extract in protecting against Aβ-mediated neurotoxicity in mammalian cells and Caenorhabditis elegans (C. elegans) models of AD. We show P. edulis pericarp protects against memory deficit and neuronal loss, and promotes longevity in the Aβ model of AD via stimulation of mitophagy, a selective cellular clearance of damaged and dysfunctional mitochondria. P. edulis pericarp also restores memory and increases neuronal resilience in a C. elegans Tau model of AD. While defective mitophagy-induced accumulation of damaged mitochondria contributes to AD progression, P. edulis pericarp improves mitochondrial quality and homeostasis through BNIP3/DCT1-dependent mitophagy and SOD-3-dependent mitochondrial resilience, both via increased nuclear translocation of the upstream transcriptional regulator FOXO3/DAF-16. Further studies to identify active molecules in P. edulis pericarp that could maintain neuronal mitochondrial homeostasis may enable the development of potential drug candidates for AD.

Clinicodemographic and Psychosocial Factors Related to Presentation or Severity of Delusions of Theft among Females with Amnestic Mild Cognitive Impairment and Alzheimer's Disease

Objectives: We examined the clinicodemographic and psychosocial factors that relate to the presentation and severity of delusions of theft among female patients with amnestic mild cognitive impairment (a-MCI) and Alzheimer's disease (AD).Methods: We enrolled a total of 177 female patients with a-MCI or AD, of whom 40 presented with delusions of theft. We compared the differences in clinicodemographic and psychosocial factors of the 40 patients (delusions of theft group) with 50 age- and Mini-Mental State Examination (MMSE)-matched controls without delusions (control group). Furthermore, we identified the factors associated with the presentation of delusions of theft using a general linear model (GLM). The severity of delusions of theft was calculated using the Neuropsychiatric Inventory Questionnaire, and correlations between the clinicodemographic and psychosocial factors were examined.Results: Between the two groups, the delusions of theft group had lower scores on the Physical Self-Maintenance Scale and instrumental activities of daily living (IADL) and higher scores on the Japanese version of the Zarit Caregiver Burden Interview (ZBI-J) than the control group. GLM analysis revealed that the IADL score was related to the presentation of delusions of theft. The severity of delusions of theft correlated with the MMSE and the ZBI-J scores in the delusions of theft group.Conclusions: The two groups had several differences regarding clinicodemographic and psychosocial factors. Furthermore, lower IADL scores were related to symptom presentation. Symptom severity correlated with cognitive functioning and caregiver burden.Clinical Implications: In the determination of treatment or care, differences in these factors should be considered.

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.

Attentional network changes in subjective cognitive decline

BACKGROUND

Subjective cognitive decline (SCD) is known as the intermediate stage between normal cognitive aging and mild cognitive impairment (MCI). Although elderly with SCD usually perform close to normal in standardized tests, the detailed function of attention networks in this group has not been studied yet.

AIMS

The purpose of this study was to investigate the performance of attention networks, as a possible indicator of cognitive disorder, in older individuals with subjective memory complaint and MCI.

METHOD

The attention network test (ANT) was used to examine and compare the performance of three attention networks of alerting, orientation, and executive control in 17 elderly with SCD, 30 multiple domain amnestic MCI subjects, and 15 healthy controls.

RESULTS

Although the orienting network had almost the same performance in all groups (p = 0.25), the performance of alerting (p = 0.01) and executive control networks (p = 0.02) were significantly different among the three groups: the SCD group performed poorly in both networks compared with the controls and did not differ significantly from the MCI group (p ≥ 0.05). However, controlling for general age-related slowing abolished the group difference in executive control index. More importantly, our results showed that alerting network that was affected in SCD group had high sensitivity in differentiating this group from controls (0.94%).

CONCLUSION

Our data suggest that despite normal performance in neuropsychological tests, the SCD elderly may face significant degrees of attention processing problems, especially in maintaining alerting to external stimuli which might be helpful in diagnosing individuals at risk and designing proper attention-based interventions.

Retention and impairment of neurocognitive functions in mild cognitive impairment and Alzheimer's disease with a comprehensive neuropsychological test

AIM

MATRICS Consensus Cognitive Battery was developed by the National Institute of Mental Health to establish acceptance criteria for measuring cognitive changes in schizophrenia and can be used to assess cognitive functions in other psychiatric disorders. We used a Japanese version of MATRICS Consensus Cognitive Battery to explore the changes in multiple cognitive functions in patients with mild cognitive impairment and mild Alzheimer's disease.

METHODS

We administered the Japanese version of MATRICS Consensus Cognitive Battery to 11 patients with mild cognitive impairment (MCI), 11 patients with Alzheimer's disease, and 27 healthy controls. All Japanese versions of MATRICS Consensus Cognitive Battery domain scores were converted to t-scores using sample means and standard deviations and were compared for significant performance differences among healthy control, MCI, and mild Alzheimer's disease groups.

RESULTS

Compared with healthy controls, patients with MCI and mild Alzheimer's disease demonstrated the same degree of impairment to processing speed, verbal learning, and visual learning. Reasoning and problem-solving showed significant impairments only in mild Alzheimer's disease. Verbal and visual abilities in working memory showed different performances in the MCI and mild Alzheimer's disease groups, with the Alzheimer's disease group demonstrating significantly more deficits in these domains. No significant difference was found among the groups in attention/vigilance and social cognition.

CONCLUSIONS

The Japanese version of MATRICS Consensus Cognitive Battery can be used to elucidate the characteristics of cognitive dysfunction of normal aging, MCI, and mild dementia in clinical practice.

Lost in Time: Temporal Monitoring Elicits Clinical Decrements in Sustained Attention Post-Stroke

OBJECTIVES

Mental fatigue, 'brain fog', and difficulties maintaining engagement are commonly reported issues in a range of neurological and psychiatric conditions. Traditional sustained attention tasks commonly measure this capacity as the ability to detect target stimuli based on sensory features in the auditory or visual domains. However, with this approach, discrete target stimuli may exogenously capture attention to aid detection, thereby masking deficits in the ability to endogenously sustain attention over time.

METHODS

To address this, we developed the Continuous Temporal Expectancy Task (CTET) where individuals continuously monitor a stream of patterned stimuli alternating at a fixed temporal interval (690 ms) and detect an infrequently occurring target stimulus defined by a prolonged temporal duration (1020 ms or longer). As such, sensory properties of target and non-target stimuli are perceptually identical and differ only in temporal duration. Using the CTET, we assessed stroke survivors with unilateral right hemisphere damage (N = 14), a cohort in which sustained attention deficits have been extensively reported.

RESULTS

Stroke survivors had overall lower target detection accuracy compared with neurologically healthy age-matched older controls (N = 18). Critically, stroke survivors performance was characterised by significantly steeper within-block performance decrements, which occurred within short temporal windows (˜3 ½ min), and were restored by the break periods between blocks.

CONCLUSIONS

These findings suggest that continuous temporal monitoring taxes sustained attention processes to capture clinical deficits in this capacity over time, and outline a precise measure of the endogenous processes hypothesised to underpin sustained attention deficits following right hemisphere stroke.

Dysfunctional Interaction Between the Dorsal Attention Network and the Default Mode Network in Patients With Type 2 Diabetes Mellitus

The risk of cognitive impairment in patients with type 2 diabetes mellitus (T2DM) is significantly higher than that in the general population, but the exact neurophysiological mechanism underlying this is still unclear. An abnormal change in the intrinsic anticorrelation of the dorsal attention network (DAN) and the default mode network (DMN) is thought to be the mechanism underlying cognitive deficits that occur in many psychiatric disorders, but this association has rarely been tested in T2DM. This study explored the relationship between the interaction patterns of the DAN-DMN and clinical/cognitive variables in patients with T2DM. Forty-four patients with T2DM and 47 sex-, age-, and education-matched healthy controls (HCs) underwent neuropsychological assessments, independent component analysis (ICA), and functional network connection analysis (FNC). The relationship of DAN-DMN anticorrelation with the results of a battery of neuropsychological tests was also assessed. Relative to the HC group, the DMN showed decreased functional connectivity (FC) in the right precuneus, and the DAN showed decreased FC in the left inferior parietal lobule (IPL) in patients with T2DM. Subsequent FNC analysis revealed that, compared with the HC group, the T2DM patients displayed significantly increased inter-network connectivity between the DAN and DMN. These abnormal changes were correlated with the scores of multiple neuropsychological assessments (P < 0.05). These findings indicate abnormal changes in the interaction patterns of the DAN-DMN may be involved in the neuropathology of attention and general cognitive dysfunction in T2DM patients.

Deep Learning With 18F-Fluorodeoxyglucose-PET Gives Valid Diagnoses for the Uncertain Cases in Memory Impairment of Alzheimer's Disease

Objectives: Neuropsychological tests are an important basis for the memory impairment diagnosis in Alzheimer’s disease (AD). However, multiple memory tests might be conflicting within-subjects and lead to uncertain diagnoses in some cases. This study proposed a framework to diagnose the uncertain cases of memory impairment.

Methods: We collected 2,386 samples including AD, mild cognitive impairment (MCI), and cognitive normal (CN) using 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) and three different neuropsychological tests (Mini-Mental State Examination, Alzheimer’s Disease Assessment Scale-Cognitive Subscale, and Clinical Dementia Rating) from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). A deep learning (DL) framework using FDG-PET was proposed to diagnose uncertain memory impairment cases that were conflicting between tests. Subsequent ANOVA, chi-squared, and t-test were used to explain the potential causes of uncertain cases.

Results: For certain cases in the testing set, the proposed DL framework outperformed other methods with 95.65% accuracy. For the uncertain cases, its positive diagnoses had a significant (p < 0.001) worse decline in memory function than negative diagnoses in a longitudinal study of 40 months on average. In the memory-impaired group, uncertain cases were mainly explained by an AD metabolism pattern but mild in extent (p < 0.05). In the healthy group, uncertain cases were mainly explained by a non-energetic mental state (p < 0.001) measured using a global deterioration scale (GDS), with a significant depression-related metabolism pattern detected (p < 0.05).

Conclusion: A DL framework for diagnosing uncertain cases of memory impairment is proposed. Proved by longitudinal tracing of its diagnoses, it showed clinical validity and had application potential. Its valid diagnoses also provided evidence and explanation of uncertain cases based on the neurodegeneration and depression mental state.

A retrospective multicentre cohort study of the performances on attention tests in outpatients with cognitive dysfunctions without delirium

OBJECTIVE

Attention is the cardinal feature of delirium, but attentional domains may also be affected by dementia and its severity. It is, therefore, of interest to study the correlation between the severity of cognitive impairment in non-delirious patients and different measurements of attentional performance, to identify attention subdomains less affected by severity of cognitive impairment.

METHODS

Neuropsychological data from non-delirious outpatients (age ≥ 65 years), presenting at two memory clinics were analysed retrospectively. Scores for selective, divided, and sustained attention were correlated with cognitive impairment as defined by the score of the Mini-Mental State Examination.

RESULTS

A total of 1658 outpatients were included. The mean age was 77.15 (± 8.17) years, with a mean MMSE score of 22.67 (± 4.91). Compared to the type of attention, the tests that are less influenced by the severity of cognitive impairment are those of selective attention, in particular the Digit Span Forward (DSF).

CONCLUSIONS

This is the first study to correlate deficits in attention subdomains with the degree of cognitive impairment in non-delirious patients. The results suggest that measurements of selective attention (i.e. DSF) might be better suited to discriminate delirium from dementia. Indeed, a lower score on these tests might be indicative of an acute change and worsening of the baseline inattention and a longitudinal monitoring of these changes might be used to determine the delirium resolution.

Distinct profiles of functional connectivity density aberrance in Alzheimer's disease and mild cognitive impairment

INTRODUCTION

Investigating the neuroimaging changes from mild cognitive impairment (MCI) to Alzheimer's disease (AD) is of great significance. However, the details about the distinct functional characteristics of AD and MCI remain unknown.

METHODS

In this study, we investigated distinct profiles of functional connectivity density (FCD) differences between AD and MCI compared with the normal population, aiming to depict the progressive brain changes from MCI to AD. As a data-driven method, FCD measures the profiles of FC for the given voxel at different scales. Resting-state functional magnetic resonance imaging (fMRI) images were obtained from patients with AD and MCI and matched healthy controls (HCs). One-way ANCOVA was used to investigate (global, long-range, and local) FCD differences among the three groups followed by post-hoc analysis controlling age, sex, and head motion.

RESULTS

The three groups exhibited significant global FCD differences in the superior frontal gyrus. The post-hoc results further showed that patients with AD had a significant increase in global FCD values than those with MCI and HCs. Patients with MCI exhibited an increased trend compared with HCs. We further identified brain regions contributing to the observed global FCD differences by conducting seed-based FC analysis. We also identified that the observed global FCD differences were the additive effects of altered FC between the superior frontal gyrus and the posterior default model network.

DISCUSSION

These results depicted the global information communication capability impairment in AD and MCI providing a new insight into the progressive brain changes from MCI to AD.

Anticholinergic medication burden and cognitive function in participants of the ASPREE study

STUDY OBJECTIVE

What is the association between anticholinergic burden and specific domains of cognitive function in older adults who are initially without major cognitive impairment?

DESIGN

Post-hoc analysis of longitudinal observational data from the ASPirin in Reducing Events in the Elderly (ASPREE) study.

PATIENTS

19,114 participants from Australia and the United States aged 70 years and older (65 years and older for US minorities) were recruited and followed for a median of 4.7 years. At enrollment, participants were free of known cardiovascular disease, major physical disability, or dementia.

MEASUREMENTS

Cognitive assessments administered at baseline and biennially at follow-up visits included the Modified Mini-Mental State examination (3MS), Hopkins Verbal Learning Test-Revised (HVLT-R) delayed recall, Controlled Oral Word Association Test (COWAT), and Symbol Digit Modalities Test (SDMT). Anticholinergic burden was calculated at baseline using the Anticholinergic Cognitive Burden (ACB) scale and grouped as scores of 0 (no burden), 1-2 (low to moderate), or 3+ (high).

MAIN RESULTS

Linear mixed effects models were used to assess the relationship between ACB score and cognition over time. After adjusting for sex, age, education, minority status, smoking status, hypertension, diabetes, depression, chronic kidney disease, country, and frailty, participants with a high ACB score had worse performance over time for 3MS (Adjusted [Adj] B=-0.092, P=0.034), HVLT-R delayed recall (Adj B=-0.104, P<0.001), COWAT (Adj B=-0.151, P<0.001), and SDMT (Adj B=-0.129, P=0.026), than participants with an ACB score of 0. A low to moderate ACB score was also associated with worse performance over time for HVLT-R delayed recall (Adj B=-0.037, P=0.007) and COWAT (Adj B=-0.065, P=0.003), compared to those with no ACB.

CONCLUSIONS

Anticholinergic burden predicts worse cognitive function over time in initially dementia-free older adults, particularly for executive function (COWAT) and episodic memory (HVLT-R).

From aMCI to AD: The Role of Visuo-Spatial Memory Span and Executive Functions in Egocentric and Allocentric Spatial Impairments

A difficulty in encoding spatial information in an egocentric (i.e., body-to-object) and especially allocentric (i.e., object-to-object) manner, and impairments in executive function (EF) are typical in amnestic mild cognitive impairment (aMCI) and Alzheimer’s disease (AD). Since executive functions are involved in spatial encodings, it is important to understand the extent of their reciprocal or selective impairment. To this end, AD patients, aMCI and healthy elderly people had to provide egocentric (What object was closest to you?) and allocentric (What object was closest to object X?) judgments about memorized objects. Participants’ frontal functions, attentional resources and visual-spatial memory were assessed with the Frontal Assessment Battery (FAB), the Trail Making Test (TMT) and the Corsi Block Tapping Test (forward/backward). Results showed that ADs performed worse than all others in all tasks but did not differ from aMCIs in allocentric judgments and Corsi forward. Regression analyses showed, although to different degrees in the three groups, a link between attentional resources, visuo-spatial memory and egocentric performance, and between frontal resources and allocentric performance. Therefore, visuo-spatial memory, especially when it involves allocentric frames and requires demanding active processing, should be carefully assessed to reveal early signs of conversion from aMCI to AD.

The Free Association Task: Proposal of a Clinical Tool for Detecting Differential Profiles of Semantic Impairment in Semantic Dementia and Alzheimer’s Disease

Backround and Objectives: It is widely agreed that patients suffering from Alzheimer’s disease (AD) and patients suffering from semantic dementia (SD) might fail clinically administered semantic tasks due to a different combination of underlying cognitive deficits: namely, degraded semantic representations in SD and degraded representations plus executive control deficit in AD. However, no easy administrable test or test battery for differentiating the semantic impairment profile in these populations has been devised yet. Materials and Methods: In this study, we propose a new easy administrable task based on a free association procedure (F-Assoc) to be used in conjunction with category fluency (Cat-Fl) and letter fluency (Lett-Fl) for quantifying pure representational and pure control deficits, thus teasing apart the semantic profile of SD and AD patients. Results: In a sample of 10 AD and 10 SD subjects, matched for disease severity, we show that indices of asymmetric performance contrasting F-Assoc and each of the two verbal fluency tasks yield a clearly distinguishable discrepancy pattern across SD and AD. We also provide empirical support for the validity of an asymmetry measure contrasting F-Assoc and Cat-FL as an index of control impairment. Conclusions: The present study suggests that the free association procedure provides a pure measure of degradation of semantic representations avoiding the confound of possible concomitant executive deficits.

Cognitive Impairment in Late-Life Depression: A Comparative Study of Healthy Older People, Late-Life Depression, and Mild Alzheimer's Disease Using Multivariate Base Rates of Low Scores

Late-Life Depression (LLD) is often associated with cognitive impairment. However, distinction between cognitive impairment due to LLD and those due to normal aging or mild Alzheimer's Disease (AD) remain difficult. The aim of this study was to present and compare the multivariate base rates of low scores in LLD, mild AD, and healthy control groups on a battery of neuropsychological tests. Participants (ages 60-89) were 352 older healthy adults, 390 patients with LLD, and 234 patients with mild AD (i.e., MMSE ≥ 20). Multivariate base rates of low scores (i.e., ≤ 5th percentile) were calculated for each participant group within different cognitive domains (verbal episodic memory, executive skills, mental processing speed, constructional praxis, and language/semantic memory). Obtaining at least one low score was relatively common in healthy older people controls (from 9.4 to 17.6%), and may thus result in a large number of false positives. By contrast, having at least two low scores was unusual (from 0.3 to 4.6%) and seems to be a more reliable criterion for identifying cognitive impairment in LLD. Having at least three low memory scores was poorly associated with LLD (5.9%) compared to mild AD (76.1%) and may provide a useful way to differentiate between these two conditions [χ ( 1 ) 2 = 329.8, p < 0.001; Odds Ratio = 50.7, 95% CI = 38.2-77.5]. The multivariate base rate information about low scores in healthy older people and mild AD may help clinicians to identify cognitive impairments in LLD patients, improve the clinical decision-making, and target those who require regular cognitive and clinical follow-up.

Elevated Plasma Free Fatty Acid Susceptible to Early Cognitive Impairment in Type 2 Diabetes Mellitus

BACKGROUND

Elevated free fatty acid (FFA) induces lipotoxicity, attributed to diabetes and cognitive decline. Sterol regulatory element-binding protein-1c (SREBP-1c) regulates lipid metabolism.

OBJECTIVE

We investigated the roles of FFA in mild cognitive impairment (MCI) of type 2 diabetes mellitus (T2DM) patients and determine its association with rs11868035 polymorphism.

METHODS

We recruited 191 Chinese T2DM patients into two groups through Montreal Cognitive Assessment. Demographic and clinical data were collected, multiple domain cognitive functions were tested, plasma FFA levels were measured through ELISA, and SREBP-1c rs11868035 genotype was detected using the Seqnome method.

RESULTS

In comparison with the healthy-cognition group (n = 128), the MCI group (n = 63) displayed lower glucose control (p = 0.012) and higher plasma FFA level (p = 0.021), which were independent risk factors of MCI in T2DM patients in multivariate regression analysis (OR = 1.270, p = 0.003; OR = 1.005, p = 0.036). Additionally, the plasma FFA levels of MCI patients were positively correlated with Stroop color word test-C time scores (r = 0.303, p = 0.021) and negatively related to apolipoprotein A1 levels (r = -0.311, p = 0.017), which are associated positively with verbal fluency test scores (r = 0.281, p = 0.033). Both scores reflected attention ability and executive function. Moreover, the G allele carriers of rs11868035 showed higher digit span test scores than non-carriers in T2DM patients (p = 0.019) but without correlation with plasma FFA levels.

CONCLUSION

In T2DM, elevated plasma level of FFA, when combined with lower apolipoprotein A1 level portends abnormal cholesterol transport, were susceptible to early cognitive impairment, especially for attention and execution deficits. The G allele of SREBP-1c rs11868035 may be a protective factor for memory.

Acute Exercise and Cognitive Function in Alzheimer's Disease

BACKGROUND

Many studies have shown the impact of acute aerobic exercises (AAE) on cognition in healthy adults or at a pre-dementia stage. Few studies, however, have explored the positive effects of AAE in moderate Alzheimer's disease (ADM) patients.

OBJECTIVE

Evaluating the effect of AAE on cognitive functions in ADM patients.

METHODS

Overall, 79 (age: 69.62±0.99) ADM patients were recruited. Participants were divided into three groups according to the task: aerobic exercises done alone or combined with cognitive games presented on a screen, and a control group who performed a reading task. The aerobic exercise protocol consisted of a 20-min cycling exercise of moderate intensity, corresponding to 60%of the individual target maximal heart rate recorded in a 6-minute walking test. The participants' cognition was monitored before and after the intervention using the Tower of Hanoi, Digit Span, and Stroop tasks.

RESULTS

After the exercise, the participants' attention in both the physical and combined groups improved for the Stroop, the forward and backward Digit Span tasks, as well as the time taken to solve the Tower of Hanoi, although no significant differences were found in the number of moves taken in the latter. By contrast, the control group did not show any significant improvement for most of the cognitive tasks after the reading session.

CONCLUSION

Current evidence suggests that AAE may help to improve cognitive functions in ADM patients. This improvement is enhanced when the exercise is combined with cognitive games. Safe and progressive types of exercises should be promoted among ADM patients.

The influence of visual attention on memory-based preferential choice

Many decisions rely on past experiences. Recent research indicates that people's choices are biased towards choosing better-remembered options, even if these options are comparatively unattractive (i.e., a memory bias). In the current study, we used eye tracking to compare the influence of visual attention on preferential choice between memory-based and non-memory-based decisions. Participants completed the remember-and-decide task. In this task, they first learned associations between screen locations and snack items. Then, they made binary choices between snack items. These snacks were either hidden and required recall (memory-based decisions), or they were visible (non-memory-based decisions). Remarkably, choices were more strongly influenced by attention in memory-based compared to non-memory-based decisions. However, visual attention did not mediate the memory bias on preferential choices. Finally, we adopt and expand a recently proposed computational model to provide a comprehensive description of the role of attention in memory-based decisions. In sum, the present work elucidates how visual attention interacts with episodic memory and preference formation in memory-based decisions.

Differences between episodic and semantic memory in predicting observation-based activities of daily living in mild cognitive impairment and Alzheimer's disease

Individuals with mild cognitive impairment (MCI) can often progress into Alzheimer's Disease (AD). Research suggests that decline in episodic memory and semantic memory, as well as functional abilities, can be sensitive in predicting disease progression. This study aimed to (a) investigate episodic and semantic memory performance differences between AD and MCI, (b) determine if memory performance predicts observation-based activities of daily living (ADLs), and (c) explore whether semantic memory mediates the relationship between episodic memory and ADLs. Fifty-eight AD, 53 MCI, and 72 healthy control participants were administered the Rey-O, California Verbal Learning Test, Animal Fluency Test, Boston Naming Test, and Direct Assessment of Functional Status (DAFS). The results revealed, first, that AD participants performed significantly lower than the MCI participants across semantic memory and episodic memory tasks, with the exception of the Boston Naming Test. Second, hierarchical-stepwise regression analyses found that semantic memory significantly predicted DAFS orientation, communication, and financial skills in AD, but episodic memory predicted shopping skills. Furthermore, semantic memory significantly predicted DAFS transportation skills in AD and MCI. Third, within the overall sample, semantic memory mediated the relationship between episodic memory and ADLs. Taken together, the findings suggest decline in semantic memory (as measured by confrontational naming and category fluency) and episodic memory (as measured by list and complex visual design learning and recall) may lead to decline in different and specific aspects of functional abilities in AD and MCI.

Effect of Acupuncture Stimulation of Hegu (LI4) and Taichong (LR3) on the Resting-State Networks in Alzheimer's Disease: Beyond the Default Mode Network

It was reported that acupuncture could treat Alzheimer's disease (AD) with the potential mechanisms remaining unclear. The aim of the study is to explore the effect of the combination stimulus of Hegu (LI4) and Taichong (LR3) on the resting-state brain networks in AD, beyond the default network (DMN). Twenty-eight subjects including 14 AD patients and 14 healthy controls (HCs) matched by age, gender, and educational level were recruited in this study. After the baseline resting-state MRI scans, the manual acupuncture stimulation was performed for 3 minutes, and then, another 10 minutes of resting-state fMRI scans was acquired. In addition to the DMN, five other resting-state networks were identified by independent component analysis (ICA), including left frontal parietal network (lFPN), right frontal parietal network (rFPN), visual network (VN), sensorimotor network (SMN), and auditory network (AN). And the impaired connectivity in the lFPN, rFPN, SMN, and VN was found in AD patients compared with those in HCs. After acupuncture, significantly decreased connectivity in the right middle frontal gyrus (MFG) of rFPN (P = 0.007) was identified in AD patients. However, reduced connectivity in the right inferior frontal gyrus (IFG) (P = 0.047) and left superior frontal gyrus (SFG) (P = 0.041) of lFPN and some regions of the SMN (the left inferior parietal lobula (P = 0.004), left postcentral gyrus (PoCG) (P = 0.001), right PoCG (P = 0.032), and right MFG (P = 0.010)) and the right MOG of VN (P = 0.003) was indicated in HCs. In addition, after controlling for the effect of acupuncture on HCs, the functional connectivity of the right cerebellum crus I, left IFG, and left angular gyrus (AG) of lFPN showed to be decreased, while the left MFG of IFPN and the right lingual gyrus of VN increased in AD patients. These findings might have some reference values for the interpretation of the combination stimulus of Hegu (LI4) and Taichong (LR3) in AD patients, which could deepen our understanding of the potential mechanisms of acupuncture on AD.

The Relationship Between Retinal Nerve Fiber Layer Thickness and Clinical Symptoms of Alzheimer's Disease

Background/Aim: Retinal nerve fiber layer (RNFL) thickness (RT), which can reflect the status of the retinal optic nerve cells, may be affected in patients with Alzheimer's disease (AD). There are few studies on the correlation of RT of patients with AD (AD-RT) with clinical symptoms of various cognitive domains, neuropsychiatric symptoms, and activities of daily living (ADL). This study is to investigate the relationships between RT and the abovementioned clinical symptoms of AD.

Methods: A total of 96 patients with AD were included in this study. RT was measured in these patients using optical coherence tomography (OCT). Demographic variables, RT, and clinical symptoms were compared between the normal and the abnormal AD-RT groups. Clinical symptoms, including cognitive symptoms, neuropsychiatric symptoms, and ADL, were evaluated using a series of rating scales.

Results: The relationships between RT and cognitive symptoms scores were analyzed in patients with AD. Reduced RT was found in 54.4% of patients with AD. The average RT, RT of the superior 1/2 quadrant, and RT of the inferior 1/2 quadrant of both eyes were all significantly decreased in the abnormal AD-RT group (p < 0.001). Overall cognitive function and performance in multiple cognitive domains, including memory, language, attention, and executive function, were also significantly impaired in the abnormal AD-RT group (p < 0.05). For lower RT value, the global cognitive function and the performance in multiple cognitive domains were worse. ADL was significantly compromised in patients with AD having lower RT values (p < 0.05).

Conclusions: Lower RT value appear to be correlated with cognitive impairment, and RT may be an indicator of cognitive decline in patients with AD. Further studies are required to confirm our findings.

Quantitative Longitudinal Predictions of Alzheimer's Disease by Multi-Modal Predictive Learning

BACKGROUND

Quantitatively predicting the progression of Alzheimer's disease (AD) in an individual on a continuous scale, such as the Alzheimer's Disease Assessment Scale-cognitive (ADAS-cog) scores, is informative for a personalized approach as opposed to qualitatively classifying the individual into a broad disease category.

OBJECTIVE

To evaluate the hypothesis that the multi-modal data and predictive learning models can be employed for future predicting ADAS-cog scores.

METHODS

Unimodal and multi-modal regression models were trained on baseline data comprised of demographics, neuroimaging, and cerebrospinal fluid based markers, and genetic factors to predict future ADAS-cog scores for 12, 24, and 36 months. We subjected the prediction models to repeated cross-validation and assessed the resulting mean absolute error (MAE) and cross-validated correlation (ρ) of the model.

RESULTS

Prediction models trained on multi-modal data outperformed the models trained on single modal data in predicting future ADAS-cog scores (MAE12, 24 & 36 months= 4.1, 4.5, and 5.0, ρ12, 24 & 36 months= 0.88, 0.82, and 0.75). Including baseline ADAS-cog scores to prediction models improved predictive performance (MAE12, 24 & 36 months= 3.5, 3.7, and 4.6, ρ12, 24 & 36 months= 0.89, 0.87, and 0.80).

CONCLUSION

Future ADAS-cog scores were predicted which could aid clinicians in identifying those at greater risk of decline and apply interventions at an earlier disease stage and inform likely future disease progression in individuals enrolled in AD clinical trials.

Assessing natural metalinguistic skills in people with Alzheimer's disease and frontotemporal dementia

OBJECTIVE

The aim of this paper is to assess whether the use of natural metalinguistic skills can be used to differentiate linguistic-communicative profiles of people with dementia (Alzheimer's disease and frontotemporal dementia in the behavioural and primary progressive aphasia variants) in the earliest stages of the disease.

METHOD

A sample of 180 people was selected. Sixty had Alzheimer's disease, 20 had frontotemporal dementia of the behavioural variant, and 40 had frontotemporal dementia of the primary progressive aphasia variant (20 had non-fluent primary progressive aphasia and 20 had semantic dementia). The control group was composed of 60 healthy people with ages, gender, and professions as similar as possible to those of the people in the dementia groups. All the participants were administered the Spanish adaptation of the Mini-Mental State Examination (MMSE) and the Global Deterioration Scale (GDS) to assess dementia severity. To assess the use of natural metalinguistic skills, a 40-item test (MetAphAs), specifically designed for this aim, was administered.

RESULTS

The test showed high internal validity and high positive correlations with the MMSE. Statistically significant differences were observed in the total scores on this test and in the scores on each of its sections, when comparing the whole group and the subgroups of people with dementia with the control group. Additionally, the scores on most of the sections of the MetAphAs test presented statistically significant differences when the different subgroups of people with dementia were compared.

CONCLUSIONS

A test like the MetAphAs, specifically designed to assess natural metalinguistic abilities, may be useful for obtaining differential communicative-linguistic profiles according to the type of dementia in the early stages of the disease. However, additional research is needed to obtain more conclusive results.

Beta-band modulation in the human hippocampus during a conflict response task

Objective Identify the role of beta-band (13-30 Hz) power modulation in the human hippocampus during conflict processing. Approach We investigated changes in the spectral power of the beta band (13-30 Hz) as measured by depth electrode leads in the hippocampus during a modified Stroop task in six patients with medically-refractory epilepsy. Previous work done with direct electrophysiological recordings in humans has shown hippocampal theta-band (3-8 Hz) modulation during conflict processing. Local field potentials (LFP) sampled at 2k Hz were used for analysis and a non-parametric cluster-permutation t-test was used to identify the time period and frequency ranges of significant power change during cue processing (i.e. post-stimulus, pre-response). Main Results In five of the six patients, we observe a statistically significant increase in hippocampal beta-band power during successful conflict processing in the incongruent trial condition (cluster-based correction for multiple comparisons, p < 0.05). There was no significant beta-band power change observed during the cue processing period of the congruent condition in the hippocampus of these patients. Significance The beta-power changes during conflict processing represented here are consistent with previous studies suggesting that the hippocampus plays a role in conflict processing, but it is the first time that the beta band has been shown to be involved in humans with direct electrophysiological evidence. We propose that beta-band modulation plays a role in successful conflict detection and automatic response inhibition in the human hippocampus as studied during a conflict response task.

Analysis of Neuropsychiatric Symptoms in Patients with Alzheimer's Disease Using Quantitative EEG and sLORETA

OBJECTIVE

The electrocortical activities associated with the neuropsychiatric symptoms (NPSs) of Alzheimer's disease (AD) were investigated using frequency-domain electroencephalography (EEG) spectral source analysis, and the potential electrocortical indices identified.

MATERIALS AND METHODS

Scalp EEG data were obtained from 51 patients with AD to investigate the presence of four NPS subdomains, hyperactivity, psychosis, affective symptoms, and apathy. EEG power spectra and the standardized low-resolution brain electromagnetic tomography (sLORETA)-localized EEG cortical sources were compared between the groups with and without the four NPS subdomains in eight frequency bands: 1-4, 4-8, 8-10, 10-12, 12-18, 18-20, 20-30, and 30-45 Hz.

RESULTS

The power spectral analysis of EEG data showed that AD patients with psychosis had lower values at the α2-band in most areas. In patients with apathy, the θ-to-β power ratio showed a greater activity over the frontal and central regions. The cortical source analysis using sLORETA revealed that patients with psychosis showed decreased values in the α2-band and patients with apathy showed higher δ-values, especially in the right frontal and temporal regions.

CONCLUSION

The results of the present study showed that both classical EEG spectral and EEG source analysis could differentiate patients with and without NPSs, especially psychosis and apathy subdomains. Spectral and sLORETA analyses provided information helpful for a better characterization in patients with NPSs.

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.

Semantic Priming in Mild Cognitive Impairment and Healthy Subjects: Effect of Different Time of Presentation of Word-Pairs

INTRODUCTION

Semantic memory is impaired in mild cognitive impairment (MCI). Twomain hypotheses about this finding are debated and refer to the degradation of stored knowledgeversus the impairment of semantic access mechanisms. The aim of our study is to evaluate semanticimpairment in MCI versus healthy subjects (HS) by an experiment evaluating semantic priming.

METHODS

We enrolled 27 MCI and 20 HS. MCI group were divided, according to follow up, intoconverters-MCI and non converters-MCI. The semantic task consisted of 108 pairs of words, 54 ofwhich were semantically associated. Stimuli were presented 250 or 900 ms later the appearance ofthe target in a randomized manner. Data were analyzed using factorial ANOVA.

RESULTS

Both HSand MCI answered more quickly for word than for non-word at both stimulus onset asynchrony(SOA) intervals. At 250 ms, both MCI and HS experienced a shorter time of response for relatedwordthan for unrelated words (priming effect), while only the converters-MCI subgroup lost thepriming effect. Further, we observed a rather larger Cohen's d effect size in non converters-MCIthan in converters-MCI.

CONCLUSION

Our data, and in particular the absence of a semantic primingeffect in converters-MCI, could reflect the impairment of semantic knowledge rather than theaccessibility of semantic stores in MCI individuals that progress to dementia.

Potential New Approaches for Diagnosis of Alzheimer's Disease and Related Dementias

Dementia is an umbrella term-caused by a large number of specific diagnoses, including several neurodegenerative disorders. Alzheimer's disease (AD) is now the most common cause of dementia in advanced countries, while dementia due to neurosyphilis was the leading cause a century ago. Many challenges remain for diagnosing dementia definitively. Some of these include variability of early symptoms and overlap with similar disorders, as well as the possibility of combined, or mixed, etiologies in some cases. Newer technologies, including the incorporation of PET neuroimaging and other biomarkers (genomics and proteomics), are being incorporated into revised diagnostic criteria. However, the application of novel diagnostic methods at clinical sites is plagued by many caveats including availability and access. This review surveys new diagnostic methods as well as remaining challenges-for clinical care and clinical research.

Subjective cognitive impairment: Functional MRI during a divided attention task

Background

Individuals with subjective cognitive impairment (SCI) have persistent memory complaints but normal neurocognitive performance. For some, this may represent a pre-mild cognitive impairment (MCI) stage of Alzheimer's disease (AD). Given that attentional deficits and associated brain activation changes are present early in the course of AD, we aimed to determine whether SCI is associated with brain activation changes during attentional processing.

Methods

Eleven SCI subjects and 10 controls completed a divided attention task during functional magnetic resonance imaging.

Results

SCI and control groups did not differ in sociodemographic, neurocognitive or behavioural measures. When group activation during the divided attention task was compared, the SCI group demonstrated increased activation in left medial temporal lobe, bilateral thalamus, posterior cingulate and caudate.

Conclusion

This pattern of increased activation is similar to the pattern of decreased activation reported during divided attention in AD and may indicate compensatory changes. These findings suggest the presence of early functional changes in SCI; longitudinal studies will help to further elucidate the relationship between SCI and AD.

Effects of neuropsychiatric symptoms of dementia on reductions in activities of daily living in patients with Alzheimer's disease

AIM

In patients with Alzheimer's disease (AD), cognitive impairments cause a progressive reduction in Activities of Daily Living (ADL). Neuropsychiatric symptoms (NPS) also appear in most patients; however, the association between NPS and reductions in ADL remains unclear. The present study evaluated whether NPS influence such reductions using two different ADL measures in patients with AD.

METHODS

Among 546 consecutive outpatients who visited the memory clinic at the Jikei University Kashiwa Hospital, we recruited 208 patients with AD and investigated the correlations between either the Physical Self-Maintenance Scale (PSMS) score or the Instrumental ADL (IADL) level, and each of the Behavioral Pathology in AD (Behave-AD) subscales. To clarify the causal relationships of these correlations, we then verified the associations between statistically significant demographic variables and the Behave-AD subscales as well as the two ADL scales (PSMS score and IADL percentage) using a general linear model.

RESULTS

Neither the PSMS nor the IADL results were significantly influenced by the aberrant motor behaviors score. However, the IADL was significantly influenced by the Mini-Mental State Exam (MMSE) score. Furthermore, diurnal rhythm disturbances and the interaction between diurnal rhythm disturbances score and the MMSE score significantly influenced the PSMS results.

CONCLUSION

Basic ADL reductions may be influenced by diurnal rhythm disturbances, in addition to cognitive impairments in patients with AD. Furthermore, the interaction between the diurnal rhythm disturbances score and cognitive function may also influence basic ADL. Geriatr Gerontol Int 2020; ••: ••-••.

Sex differences in the severity of neuropsychiatric symptoms and their relationship with clinico-demographic and psychosocial factors in patients with amnestic mild cognitive impairment and mild Alzheimer's disease

Objectives: We examined differences in the severity of neuropsychiatric symptoms (NPS) according to sex and identified NPS-related clinico-demographic and psychosocial factors among community-living patients with amnestic-mild cognitive impairment (a-MCI) or mild Alzheimer's disease (AD).Method: Overall, 111 patients (44 males, 67 females) with mild a-MCI (n = 64) or mild AD (n = 47) were included. We divided the patients according to sex and compared their clinico-demographic and psychosocial factors, explored the severity of NPS using the subscales from the Neuropsychiatric Inventory-Questionnaire (NPI-Q), and further identified variables related to NPS.Results: Significant differences in several clinico-demographic and psychosocial characteristics were observed between the sexes. The severity of delusions was higher among females (mean, 0.48; SD, 1.60) than males (mean, 0.23; SD, 1.07; p = .02), while the severity of irritability was higher among males (mean, 0.97; SD, 1.92) than females (mean, 0.49; SD, 1.40; p = .03). The severity of delusions among females was related to the duration of cognitive decline (B = 0.37, p = .03), while the severity of irritability among males was related to general cognition (B = -0.40, p = .003).Conclusion: The severity of NPS among patients with a-MCI or mild AD differed according to sex. We identified NPS-related clinico-demographic factors among these patients. Sex differences should be considered when determining the need for NPS interventions.

Effects of Visual Aids for End-of-Life Care on Decisional Capacity of People With Dementia

Purpose This study evaluated the decision-making capacity of persons with mild and moderate dementia on end-of-life care when using visual aids. A secondary purpose was to learn whether the judges naive to the experimental conditions would rate participants' decisional abilities as better when augmented by visual aids, thereby validating the behavioral changes due to the use of these external support. Method Twenty older adults with mild and moderate dementia demonstrated Understanding, Expressing a Choice, Reasoning, and Appreciation of 2 medical vignettes under 2 counterbalanced conditions: verbal alone or verbal with visual aids. Transcripts were analyzed and scored to measure decisional skills. Twelve judges rated participants' decisional abilities using a 7-point Likert scale. Results Participants demonstrated significantly better overall decisional capacity in Understanding, Reasoning, and Appreciation when supported by visual aids during the decision-making process. No significant differences between conditions were found in Expressing a Choice, the decisional skill Logical Sequence under Reasoning, and Acknowledgment under Appreciation. Overall, the judges' ratings validated these outcomes; the judges' ratings reflected greater agreement in the visual condition than in the verbal condition. Conclusions Findings indicated that visual aids (a) improved the decision-making capacity of individuals with dementia in comprehending medical information, employing supportive reasons, and relating this information to his or her own situation and (b) contain the potential for judges who majored or are majoring in speech-language pathology to reach a stronger consensus when determining the decision-making capacity of individuals with dementia.

A smartphone-based test for the assessment of attention deficits in delirium: A case-control diagnostic test accuracy study in older hospitalised patients

BACKGROUND

Delirium is a common and serious acute neuropsychiatric syndrome which is often missed in routine clinical care. Inattention is the core cognitive feature. Diagnostic test accuracy (including cut-points) of a smartphone Delirium App (DelApp) for assessing attention deficits was assessed in older hospital inpatients.

METHODS

This was a case-control study of hospitalised patients aged ≥65 years with delirium (with or without pre-existing cognitive impairment), who were compared to patients with dementia without delirium, and patients without cognitive impairment. Reference standard delirium assessment, which included a neuropsychological test battery, was based on Diagnostic and Statistical Manual of Mental Disorders-5 criteria. A separate blinded assessor administered the DelApp arousal assessment (score 0-4) and attention task (0-6) yielding an overall score of 0 to 10 (lower scores indicate poorer performance). Analyses included receiver operating characteristic curves and sensitivity and specificity. Optimal cut-points for delirium detection were determined using Youden's index.

RESULTS

A total of 187 patients were recruited, mean age 83.8 (range 67-98) years, 152 (81%) women; n = 61 with delirium; n = 61 with dementia without delirium; and n = 65 without cognitive impairment. Patients with delirium performed poorly on the DelApp (median score = 4/10; inter-quartile range 3.0, 5.5) compared to patients with dementia (9.0; 5.5, 10.0) and those without cognitive impairment (10.0; 10.0, 10.0). Area under the curve for detecting delirium was 0.89 (95% Confidence Interval 0.84, 0.94). At an optimal cut-point of ≤8, sensitivity was 91.7% (84.7%, 98.7%) and specificity 74.2% (66.5%, 81.9%) for discriminating delirium from the other groups. Specificity was 68.3% (56.6%, 80.1%) for discriminating delirium from dementia (cut-point ≤6).

CONCLUSION

Patients with delirium (with or without pre-existing cognitive impairment) perform poorly on the DelApp compared to patients with dementia and those without cognitive impairment. A cut-point of ≤8/10 is suggested as having optimal sensitivity and specificity. The DelApp is a promising tool for assessment of attention deficits associated with delirium in older hospitalised adults, many of whom have prior cognitive impairment, and should be further validated in representative patient cohorts.

MouseBytes, an open-access high-throughput pipeline and database for rodent touchscreen-based cognitive assessment

Open Science has changed research by making data accessible and shareable, contributing to replicability to accelerate and disseminate knowledge. However, for rodent cognitive studies the availability of tools to share and disseminate data is scarce. Automated touchscreen-based tests enable systematic cognitive assessment with easily standardised outputs that can facilitate data dissemination. Here we present an integration of touchscreen cognitive testing with an open-access database public repository (mousebytes.ca), as well as a Web platform for knowledge dissemination (https://touchscreencognition.org). We complement these resources with the largest dataset of age-dependent high-level cognitive assessment of mouse models of Alzheimer’s disease, expanding knowledge of affected cognitive domains from male and female mice of three strains. We envision that these new platforms will enhance sharing of protocols, data availability and transparency, allowing meta-analysis and reuse of mouse cognitive data to increase the replicability/reproducibility of datasets.

Alzheimer's Disease, Visual Search, and Instrumental Activities of Daily Living: A Review and a New Perspective on Attention and Eye Movements

Many instrumental activities of daily living (IADLs), like cooking and managing finances and medications, involve finding efficiently and in a timely manner one or several objects within complex environments. They may thus be disrupted by visual search deficits. These deficits, present in Alzheimer's disease (AD) from its early stages, arise from impairments in multiple attentional and memory mechanisms. A growing body of research on visual search in AD has examined several factors underlying search impairments in simple arrays. Little is known about how AD patients search in real-world scenes and in real settings, and about how such impairments affect patients' functional autonomy. Here, we review studies on visuospatial attention and visual search in AD. We then consider why analysis of patients' oculomotor behavior is promising to improve understanding of the specific search deficits in AD, and of their role in impairing IADL performance. We also highlight why paradigms developed in research on real-world scenes and real settings in healthy individuals are valuable to investigate visual search in AD. Finally, we indicate future research directions that may offer new insights to improve visual search abilities and autonomy in AD patients.

Ghrelin in Alzheimer's disease: Pathologic roles and therapeutic implications

Ghrelin, which has many important physiological roles, such as stimulating food intake, regulating energy homeostasis, and releasing insulin, has recently been studied for its roles in a diverse range of neurological disorders. Despite the several functions of ghrelin in the central nervous system, whether it works as a therapeutic agent for neurological dysfunction has been unclear. Altered levels and various roles of ghrelin have been reported in Alzheimer's disease (AD), which is characterized by the accumulation of misfolded proteins resulting in synaptic loss and cognitive decline. Interestingly, treatment with ghrelin or with the agonist of ghrelin receptor showed attenuation in several cases of AD-related pathology. These findings suggest the potential therapeutic implications of ghrelin in the pathogenesis of AD. In the present review, we summarized the roles of ghrelin in AD pathogenesis, amyloid beta (Aβ) homeostasis, tau hyperphosphorylation, neuroinflammation, mitochondrial deficit, synaptic dysfunction and cognitive impairment. The findings from this review suggest that ghrelin has a novel therapeutic potential for AD treatment. Thus, rigorously designed studies are needed to establish an effective AD-modifying strategy.