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

TAK-915, a phosphodiesterase 2A inhibitor, ameliorates the cognitive impairment associated with aging in rodent models

Changes in the cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) signaling are implicated in older people with dementia. Drugs that modulate the cAMP/cGMP levels in the brain might therefore provide new therapeutic options for the treatment of cognitive impairment in aging and elderly with dementia. Phosphodiesterase 2A (PDE2A), which is highly expressed in the forebrain, is one of the key phosphodiesterase enzymes that hydrolyze cAMP and cGMP. In this study, we investigated the effects of PDE2A inhibition on the cognitive functions associated with aging, such as spatial learning, episodic memory, and attention, in rats with a selective, brain penetrant PDE2A inhibitor, N-{(1S)-1-[3-fluoro-4-(trifluoromethoxy)phenyl]-2-methoxyethyl-7-methoxy-2-oxo-2,3-dihydropyrido[2,3-b]pyrazine-4(1H)-carboxamide (TAK-915). Repeated treatment with TAK-915 (3 mg/kg/day, p.o. for 4 days) significantly reduced escape latency in aged rats in the Morris water maze task compared to the vehicle treatment. In the novel object recognition task, TAK-915 (1, 3, and 10 mg/kg, p.o.) dose-dependently attenuated the non-selective muscarinic antagonist scopolamine-induced memory deficits in rats. In addition, oral administration of TAK-915 at 10 mg/kg significantly improved the attentional performance in middle-aged, poorly performing rats in the 5-choice serial reaction time task. These findings suggest that PDE2A inhibition in the brain has the potential to ameliorate the age-related cognitive decline.

Can we predict amyloid deposition by objective cognition and regional cerebral blood flow in patients with subjective cognitive decline?

BACKGROUND

Subjective cognitive decline (SCD) may herald the first symptoms of Alzheimer's disease (AD) whereas individuals with beta-amyloid (Aβ) deposition are regarded as a high-risk group for AD. Recently, amyloid positron emission tomography (PET) studies have demonstrated clinical and cognitive feature differences between Aβ-positive and negative SCD, but details of their differences remain unclear. We aimed to investigate the relationships among Aβ deposition, clinical, and cognitive features in patients with SCD.

METHODS

Forty-two patients with SCD (22 women, 74.5 ± 4.7 years) were examined using fluorine-18 florbetaben PET and were divided into Aβ-positive (n = 10) and negative (n = 32) groups. We compared cognitive and psychological outcomes, and single photon emission computed tomography (SPECT) imaging data between the two groups. In addition, a linear regression analysis was performed to assess relationships between the severity of SCD and neuropsychological tests, affective scores, and demographic factors.

RESULTS

The rate of score changes from the immediate recall to delayed recall in the logical memory subtest of the Wechsler's Memory Scale Revised were different between the groups (P = 0.04). However, the binary logistic regression analysis showed no significant differences between the two. In addition, the severity of SCD was significantly strong in women (P = 0.002). Furthermore, within the Aβ-negative group, subjective memory loss correlated with word fluency category score (P = 0.023) and apathy scale (P = 0.037).

CONCLUSIONS

No significant differences were observed between Aβ-positive and -negative SCD on any of the neuropsychological measures, clinical measures, or SPECT imaging. Further, the severity of SCD was not predicted by the symptoms of anxiety, depression, or neuropsychological examination.

Touchscreen games to detect cognitive impairment in senior adults. A user-interaction pilot study

INTRODUCTION

Alzheimer's disease is a degenerative brain disease and the most common cause of dementia. Today, 47 million people live with dementia worldwide. This number is projected to increase to more than 131 million by 2050, as populations age. Therefore, the World Health Organization considers serious cognitive deterioration a public health priority.

OBJECTIVES

Advanced cognitive evaluation mechanisms are needed to help make an early diagnosis. These new mechanisms should overcome the limitations of current neuropsychological tests, including delayed detection; being perceived as intrusive; being non-ecological; being dependent on confounding factors; or their administration being expensive, among others. A promising novel approach consists of the introduction of serious games based on virtual reality and machine learning able to assess cognitive traits relevant to the diagnosis of mild cognitive impairment and Alzheimer's disease.

METHODS

As a result of a preliminary pilot experiment, promising evidence was obtained about the predictive power of this solution. However, for these new serious games to be effective, evidence has to be gathered on the player experience by senior adults, avoiding the limitations of traditional tests at the same time. This study addresses these aspects with the participation of 74 senior users and 15 test administrators.

RESULTS

Main findings confirm the usability and playability of Panoramix, a game battery designed according to the principles discussed above, its technological acceptability and its accessibility. For example, in relation to acceptability, the game battery was scored 4.39 in a 5-point scale, while its average usability score was 4.45 regardless of socio-cultural level or previous experience with digital technologies. In addition, health professionals confirm both, usability and playability, levels with an average score of 6.5 in a 7-point scale. Participants' willingness of using this kind of systems for cognitive evaluation was also confirmed.

CONCLUSION

Promising results obtained pave the way for additional work to confirm the diagnostic validity according to clinical standards of these new cognitive assessment tools.

Decision support in patients with mild Alzheimer's disease

INTRODUCTION

Making advantageous decisions is a key competence of individuals of all ages. However, previous studies reported a reduction of this competence in patients with neurodegenerative diseases such as Alzheimer's disease, which is explained by impairments of executive functions such as cognitive flexibility or working memory. While previous findings from healthy participants with reduced executive functions showed that support can improve decision making under risk, the study at hand aimed to investigate this effect in patients with mild Alzheimer's disease (mAD).

METHOD

A group of elderly individuals diagnosed with mAD (n = 14; mean Mini-Mental State Examination, MMSE = 24.14, SD = 3.18) and a group of healthy age-matched controls (n = 14; mean MMSE = 29.29, SD = 1.98) performed the Game of Dice Task (GDT) three times (t₀, t_1, t₂) with intervals of five to nine days between each: The standard GDT plus other neurocognitive tasks (t₀), the GDT with decision support (t₁), and again the standard GDT (t₂).

RESULTS

At any time, mAD patients made more disadvantageous decisions than controls. However, the decision-making performance of mAD patients improved significantly with decision support. Interestingly, when the standard GDT was played again (t₂), mAD patients' performance remained similar to the performance in the GDT with decision support (t₁). GDT performance correlated consistently with executive function measures in the control group, but only at t₀ in the mAD group.

CONCLUSIONS

The findings indicate that supportive information about the riskiness of options can compensate for mAD-related deficits in decision making under risk. Thus, decision support can improve the quality of mAD patients' decisions. Further, it may prevent mAD patients from making highly risky decisions in similar situations in the future. The persistence of decision support should be further investigated as it has relevant implications for everyday decisions that include risks.

CHRM2 Genotype Affects Inhibitory Control Mechanisms During Cognitive Flexibility

The cholinergic system is one of the most important neurotransmitter systems, but knowledge about the relevance of the cholinergic muscarinergic receptor system for cognitive functions is still scarce. Evidence suggests that the cholinergic muscarinic 2 receptor (CHRM2) plays an important role in the processing of cueing/prior information that help to increase the efficacy of lower-level attentional processes. In the current study, we investigated whether this is also the case for higher-level cognitive flexibility mechanisms. To this end, we tested N = 210 healthy adults with a backward inhibition task, in which prior information needs to be used to guide cognitive flexibility mechanisms. Testing different polymorphisms of the CHRM2 gene, we found that variation in this gene play a role in cognitive flexibility. It could be demonstrated that rs8191992 TT genotype carriers are better able to suppress no longer relevant information and to use prior information for cognitive flexibility, compared to A allele carriers. We further found that rs2350780 GG genotype carriers performed worse than A allele carriers. The results broaden the relevance of the CHRM2 system for cognitive functions beyond attentional selection processes. Corroborating recent theories on the relevance of the cholinergic system for cognitive processes, these results suggest that CHRM2 is important to process of "prior information" needed to inform subsequent cognitive operations. Considering the importance of prior information for adaptive behavioral control, it is possible that CHRM2 also modulates other instances of higher-level cognitive processes as long as these require the processing of "prior information."

Course of Cognitive Functioning in Institutionalized Persons With Moderate to Severe Dementia: Evidence From the Severe Impairment Battery Short Version

OBJECTIVES

To adequately monitor the course of cognitive functioning in persons with moderate to severe dementia, relevant cognitive tests for the advanced dementia stages are needed. We examined the ability of a test developed for the advanced dementia stages, the Severe Impairment Battery Short version (SIB-S), to measure cognitive change over time. Second, we examined type of memory impairment measured with the SIB-S in different dementia stages.

METHODS

Participants were institutionalized persons with moderate to severe dementia (N = 217). The SIB-S was administered at 6-month intervals during a 2-year period. Dementia severity at baseline was classified according to Global Deterioration Scale criteria. We used mixed models to evaluate the course of SIB-S total and domain scores, and whether dementia stage at baseline affected these courses.

RESULTS

SIB-S total scores declined significantly over time, and the course of decline differed significantly between dementia stages at baseline. Persons with moderately severe dementia declined faster in mean SIB-S total scores than persons with moderate or severe dementia. Between persons with moderate and moderately severe dementia, there was only a difference in the rate of decline of semantic items, but not episodic and non-semantic items.

CONCLUSIONS

Although modest floor and slight ceiling effects were noted in severe and milder cases, respectively, the SIB-S proved to be one of few available adequate measures of cognitive change in institutionalized persons with moderate to severe dementia. (JINS, 2019, 25, 204-214).

Performance on bedside tests of attention and organized thinking in patients with dementia free from delirium

ABSTRACTObjectives:Bedside tests of attention and organized thinking were performed in patients with cognitive impairment or dementia but without delirium, to provide estimates of false positive rates for detecting delirium superimposed on dementia (DSD).

DESIGN AND SETTING

This cross-sectional study was conducted in outpatients and institutionalized patients without delirium representing a wide spectrum of severity of cognitive impairments.

PARTICIPANTS

Patients with dementia or a cognitive disorder according to DSM IV criteria, after exclusion of (suspected) delirium according to DSM IV criteria.

MEASUREMENTS

Tests for inattention and disorganized thinking from the CAM-ICU were assessed.

RESULTS

The sample included 163 patients (mean age 83 years (SD 6; 64% women)), with Alzheimer's disease as most prevalent (45%) diagnosis and a mean MMSE-score of 16.8 (SD 7.5). False positive rates of the test of attention varied from 0.04 in patients with normal to borderline cognitive function to 0.8 in those with severe dementia. The false positive rate of the test of disorganized thinking was zero in the normal to borderline group, increasing to 0.67 in patients with severe dementia. When combining test results false positive rates decreased to 0.03 in patients with MMSE scores above 9.

CONCLUSION

Use of simple bedside tests of attention and organized thinking for the clinical diagnosis of DSD will result in high rates of false positive observations if used regardless of the severity of dementia. However, if test results are combined they may be useful to exclude DSD in patients with minimal to moderate degrees of dementia, but not in the severe group.

Olfactory Dysfunction and Its Relationship with Clinical Symptoms of Alzheimer Disease

Our study aimed to analyse the olfactory dysfunction (OD) evaluations between self-report, the Hyposmia Rating Scale (HRS) and the Sniffin’ Sticks test, and the relationship between OD and clinical features of AD. Sixty patients with AD dementia, 37 patients with mild cognitive impairment (MCI) due to AD and 30 healthy controls were consecutively recruited. Olfactory function was evaluated by self-report, HRS and Sniffin’ Sticks test. Patients were divided into AD with OD (AD-OD) and AD with no OD (AD-NOD) groups based on the results of the Sniffin’ Sticks test. Cognitive symptoms and neuropsychiatric symptoms were assessed by corresponding scales, and activities of daily living (ADL) were assessed by the ADL scale. In the control, MCI due to AD and AD dementia groups, the frequency of OD was 10.0%, 13.5% and 18.3%, respectively, by self-report; 6.7%, 24.3% and 48.3%, respectively, by HRS; and 3.3%, 13.5% and 65.0%, respectively, by the Sniffin’ Sticks test. Compared to the results of the Sniffin’ Sticks test, the diagnostic coincidence rates of OD by HRS in patients with MCI due to AD and AD dementia were 89.2% and 66.7%, respectively. Compared to the AD-NOD group, the scores of global cognition and memory, visuospatial ability and attention were all decreased (P<0.05), the apathy score was increased (P<0.05), and the ADL score was elevated (P<0.01). The frequency and accuracy of OD by self-report is relatively low. HRS can be used for screening olfaction in patients with MCI due to AD. The Sniffin’ Sticks test can be used for validating OD in AD patients. AD-OD patients have severe impairments in global cognition and multiple cognitive domains of memory, visuospatial ability and attention, as well as neuropsychiatric symptoms of apathy, and thus have seriously compromised ADL.

Attention, novelty preference and the visual paired comparison task

The innate ability of humans to identify, process and ascribe greater attentional resources (attention bias) to novel stimuli is essential for exploring new opportunities and consequently adapt to changing environments. One of the most common tests to assess attention bias to novel stimuli (Novelty Preference - NP) is the visual paired comparison task (VPC). In the VPC task subjects are presented with novel and previously seen images (repeated images) and NP is measured by parameters that describe visual scanning patterns on these images. The main objective of this study is to evaluate the effects of divided attention on NP. NP was measured in 26 healthy young individuals under two test conditions. In the first condition, subjects performed the VPC task and an audio task simultaneously (divided attention test condition), while in the second condition subjects performed only the VPC task (undivided attention test condition). For each test condition, repeated images were presented after delays ranging from 1.0 to 219.5 s and NP was measured by the mean difference between the relative fixation times on novel and repeated images at each delay. In the divided attention test condition, there were significant differences (p < 0.037) between the magnitudes of NPs for long delays (≥ 162 s) and short delays (≤12.5 s). Such differences were not detected in the undivided attention test condition. Analysis of variance revealed significant differences between the measured NPs during the divided and undivided attention test conditions (F(1, 25) = 18.38, p < 0.001, η² = 0.424) and significant interaction effects between delays and testing conditions (F(5,125) = 2.88, p = 0.017, η² = 0.103). Post-hoc t-tests showed significant differences between the measured NPs during the divided attention and undivided attention test conditions for long delays (162.0 and 219.5 s) but not for short delays (1.0 and 12.5 s). The results of the study are consistent with the hypothesis that for longer delays between the presentations of repeated images in the VPC task, NP is dependent on the recollection-based item recognition memory system, while for shorter delays NP is dependent on the automatic, familiarity-based item recognition memory system.

Time course of changes in motor-cognitive exergame performances during task-specific training in patients with dementia: identification and predictors of early training response

Background

Some studies have already suggested that exergame interventions can be effective to improve physical, cognitive, motor-cognitive, and psychological outcomes in patients with dementia (PwD). However, little is known about the training volume required to induce such positive effects and the inter-individual differences in training response among PwD. The aim of the study was to analyze the time course of changes in motor-cognitive exergame performances during a task-specific training program and to identify predictors of early training response in PwD.

Methods

Secondary analyses of data from the intervention group (IG) of a randomized, placebo-controlled trial to improve motor-cognitive performances in PwD. Fifty-six geriatric patients with mild-to-moderate dementia randomized to the IG underwent a 10-week, task-specific training program (2×/week) on an exergame-based balance training system (Physiomat®), combining postural control tasks with cognitive tasks of an established neuropsychological test (Trail Making Test). Main outcome was the time required to complete different Physiomat®-Tasks (PTs) assessed at baseline (T1), training session 7 (TS7) and 14 (TS14), and post-intervention after 20 training sessions (T2). Reliable change indices were used to identify early responders from T1 to TS7. A multivariate logistic regression analysis was performed to determine independent predictors of early training response.

Results

Completion time significantly improved already from T1 to TS7 in all PTs (p ≤ .001–.006), with moderate to very large effect sizes (r = .38–.52; Cohen’s d = .85–1.45). For most PTs, significant progressive improvements from TS7 to TS14 and TS14 to T2 were not observed. Thirty-one (59.6%) participants were classified as early responders and 21 (40.4%) as non-early responders. Lower baseline exergame performance and lower visuospatial and divided attention abilities were independently associated with early training response.

Conclusions

Substantial task-specific improvements in complex motor-cognitive exergame performances can be obtained within a surprisingly short intervention period in PwD. Our results confirm that not only an excellent training response can be achieved in this patient population, but also that more vulnerable patients with greater deficits in domain-specific cognitive functions associated with fall risk may even reap the most and fastest benefit from motor-cognitive exergame interventions.

Trial registration

ISRCTN registry, ISRCTN37232817 (retrospectively registered on 04/02/2012).

A quick test of cognitive speed in older adults with Alzheimer's disease and mild cognitive impairment: A preliminary behavioral and brain imaging study

The purpose of this study was to assess scores and processing speed distributions of the instrument, A Quick Test of Cognitive Speed (AQT), in Korean older adults through behavioral and brain imaging approaches. Participants were instructed to say the color names, stimuli's form, and both the color and form. Test scores and processing speeds were measured in these three subtests of color, form, and color-form. A total of 67 patients (22 healthy controls (HC), 22 with mild cognitive impairment (MCI), and 23 with Alzheimer's disease (AD)) participated. Only color-form score and processing speed of the three subtests could be used to differentiate AD from MCI and HC. Color-form score showed the largest effects size (partial η² = 0.268) for distinguishing AD, MCI from HC and ROC curve analysis confirmed a high level of sensitivity (0.857) and specificity (0.826) for discrimination between AD and HC. None of the subtests could differentiate HC from MCI. Voxel-based morphometry analysis of brain structure in 27 participants (9 in each group) revealed that gray matter volume of the middle occipital gyrus and inferior parietal cortex were associated with color-form score. This study suggests preliminary evidence in the clinical utility of the AQT for screening AD in older Korean adults. The color-form score could be implemented for clinical utilization in a very brief time. Furthermore, strong positive correlations between color-form scores and the brain areas responsible for visuospatial working memory corroborate the validity of AQT.

Episodix: a serious game to detect cognitive impairment in senior adults. A psychometric study

Introduction

Assessment of episodic memory is traditionally used to evaluate potential cognitive impairments in senior adults. The present article discusses the capabilities of Episodix, a game to assess the aforementioned cognitive area, as a valid tool to discriminate among mild cognitive impairment (MCI), Alzheimer’s disease (AD) and healthy individuals (HC); that is, it studies the game’s psychometric validity study to assess cognitive impairment.

Materials and Methods

After a preliminary study, a new pilot study, statistically significant for the Galician population, was carried out from a cross-sectional sample of senior adults as target users. A total of 64 individuals (28 HC, 16 MCI, 20 AD) completed the experiment from an initial sample of 74. Participants were administered a collection of classical pen-and-paper tests and interacted with the games developed. A total of six machine learning classification techniques were applied and four relevant performance metrics were computed to assess the classification power of the tool according to participants’ cognitive status.

Results

According to the classification performance metrics computed, the best classification result is obtained using the Extra Trees Classifier (F1 = 0.97 and Cohen’s kappa coefficient = 0.97). Precision and recall values are also high, above 0.9 for all cognitive groups. Moreover, according to the standard interpretation of Cohen’s kappa index, classification is almost perfect (i.e., 0.81–1.00) for the complete dataset for all algorithms.

Limitations

Weaknesses (e.g., accessibility, sample size or speed of stimuli) detected during the preliminary study were addressed and solved. Nevertheless, additional research is needed to improve the resolution of the game for the identification of specific cognitive impairments, as well as to achieve a complete validation of the psychometric properties of the digital game.

Conclusion

Promising results obtained about psychometric validity of Episodix, represent a relevant step ahead towards the introduction of serious games and machine learning in regular clinical practice for detecting MCI or AD. However, more research is needed to explore the introduction of item response theory in this game and to obtain the required normative data for clinical validity.

Clinical Utility of Select Neuropsychological Assessment Battery Tests in Predicting Functional Abilities in Dementia

OBJECTIVE

Neuropsychological test performance can provide insight into functional abilities in patients with dementia, particularly in the absence of an informant. The relationship between neuropsychological measures and instrumental activities of daily living (IADLs) is unclear due to hetereogeneity in cognitive domains assessed and neuropsychological tests administered. Practical and ecologically valid performance-based measures of IADLs are also limited. The Neuropsychological Assessment Battery (NAB) is uniquely positioned to provide a dual-purpose assessment of cognitive and IADL function, as it includes Daily Living tests that simulate real-world functional tasks. We examined the utility of select NAB tests in predicting informant-reported IADLs in mild cognitive impairment and dementia.

METHODS

The sample of 327 participants included 128 normal controls, 97 individuals with mild cognitive impairment, and 102 individuals with Alzheimer's disease dementia from the Boston University Alzheimer's Disease Center research registry. Informants completed the Lawton Brody Instrumental Activities of Daily Living Scale, and study participants were administered selected NAB tests that were complementary to the existing protocol.

RESULTS

ROC curves showed strongest prediction of IADL (AUC > 0.90) for memory measures (List Learning delayed recall and Daily Living Memory delayed recall) and Daily Living Driving Scenes. At a predetermined level of specificity (95%), List Learning delayed recall (71%) and Daily Living Memory delayed recall (88%) were the most sensitive. The Daily Living Memory and Driving Scenes tests strongly predicted IADL status, and the other Daily Living tests contributed unique variance.

CONCLUSIONS

NAB memory measures and Daily Living Tests may have clinical utility in detecting informant-rated functional impairment in dementia.

Baseline Predictors of Antipsychotic Treatment Continuation and Response at Week 8 in Patients with Alzheimer's Disease with Psychosis or Aggressive Symptoms: An Analysis of the CATIE-AD Study

BACKGROUND/OBJECTIVE

The aim of the present study was to investigate predictors of atypical antipsychotic (AAP) treatment continuation and response by week 8 in patients with Alzheimer's disease (AD) who have psychotic/aggressive symptoms using the Clinical Antipsychotic Trials of Intervention Effectiveness-Alzheimer's Disease (CATIE-AD) dataset.

METHODS

Clinical data was utilized from 421 AD outpatients with psychotic/aggressive symptoms who needed interventional treatment. Logistic regression analyses were performed to examine which baseline sociodemographic and clinical characteristics contributed to treatment 'continuation' and 'response', the latter of which was evaluated by the Clinical Global Impression of Change (CGI-C), Neuropsychiatric Inventory (NPI), and Brief Psychiatric Scale (BPRS).

RESULTS

The treatment continuation rate was 48.7%, and CGI-C, NPI, and BPRS response rate by the last observation carried forward method were 42.7%, 48.6%, and 37.5%, respectively. No significant predictor was identified for treatment continuation in the Caucasian patients (n = 331), while better treatment response was predicted by a lower Mini-Mental State Examination score, treatment with risperidone (versus olanzapine and quetiapine), history of diabetes mellitus, healthier physical status, and more severe initial psychotic symptoms.

CONCLUSIONS

Comparatively high intolerability from AAPs in the short term was confirmed. We found that baseline clinical predictors to treatment response in Caucasian AD patients with psychotic/aggressive symptoms include treatment with risperidone (versus quetiapine and olanzapine), diabetes mellitus, global physical status, cognitive impairment, and psychotic symptoms. Going forward, these findings may help to determine treatment strategies or care plans.

Impaired Processing of Serial Order Determines Working Memory Impairments in Alzheimer's Disease

BACKGROUND

Working memory (WM) problems are commonly observed in Alzheimer's disease (AD), but the affected mechanisms leading to impaired WM are still insufficiently understood. The ability to efficiently process serial order in WM has been demonstrated to be fundamental to fluent daily life functioning. The decreased capability to mentally process serial position in WM has been put forward as the underlying explanation for generally compromised WM performance.

OBJECTIVE

Determine which mechanisms, such as order processing, are responsible for deficient WM functioning in AD.

METHOD

A group of AD patients (n = 32) and their partners (n = 25), assigned to the control group, were submitted to an extensive battery of neuropsychological and experimental tasks, assessing general cognitive state and functioning of several aspects related to serial order WM.

RESULTS

The results revealed an impaired ability to bind item information to serial position within WM in AD patients compared to controls. It was additionally observed that AD patients experienced specific difficulties with directing spatial attention when searching for item information stored in WM.

CONCLUSION

The processing of serial order and the allocation of attentional resources are both disrupted, explaining the generally reduced WM functioning in AD patients. Further studies should now clarify whether this observation could explain disease-related problems for other cognitive functions such as verbal expression, auditory comprehension, or planning.

Mediation of episodic memory performance by the executive function network in patients with amnestic mild cognitive impairment: a resting-state functional MRI study

Deficits in episodic memory (EM) are a hallmark clinical symptom of patients with amnestic mild cognitive impairment (aMCI). Impairments in executive function (EF) are widely considered to exacerbate memory deficits and to increase the risk of conversion from aMCI to Alzheimer's disease (AD). However, the specific mechanisms underlying the interaction between executive dysfunction and memory deficits in aMCI patients remain unclear. Thus, the present study utilized resting-state functional magnetic resonance imaging (fMRI) scans of the EF network and the EM network to investigate this relationship in 79 aMCI patients and 119 healthy controls (HC). The seeds were obtained from the results of a regional homogeneity (ReHo) analysis. Functional connectivity (FC) within the EM network was determined using a seed in the right retrosplenial cortex (RSC), and FC within EF network was assessed using seeds in the right dorsolateral prefrontal cortex (DLPFC). There was a significant negative correlation between EM scores and EF scores in both the aMCI and HC groups. Compared to the HC group, aMCI patients had reduced right RSC connectivity but enhanced right DLPFC connectivity. The overlapping brain regions between the EM and EF networks were associated with FC in the right inferior parietal lobule (IPL) in the right RSC network, and in the bilateral middle cingulate cortex (MCC) and left IPL in the right DLPFC network. A mediation analysis revealed that the EF network had an indirect positive effect on EM performance in the aMCI patients. The present findings provide new insights into the neural mechanisms underlying the interaction between impaired EF and memory deficits in aMCI patients and suggest that the EF network may mediate EM performance in this population.

Subcortical hyperintensities in the cholinergic system are associated with improvements in executive function in older adults with coronary artery disease undergoing cardiac rehabilitation

OBJECTIVE

Coronary artery disease (CAD) is frequently accompanied by white matter hyperintensities and executive dysfunction. Because acetylcholine is important in executive function, these symptoms may be exacerbated by subcortical hyperintensities (SH) located in cholinergic (CH) tracts. This study investigated the effects of SH on cognitive changes in CAD patients undergoing a 48-week cardiac rehabilitation program.

METHODS

Fifty patients (age 66.5 ± 7.1 years, 84% male) underwent the National Institute of Neurological Disorders and Stroke - Canadian Stroke Network neurocognitive battery at baseline and 48 weeks. Patients underwent a 48-week cardiac program and completed neuroimaging at baseline. Subcortical hyperintensities in CH tracts were measured using Lesion Explorer. Repeated measures general linear models were used to examine interactions between SH and longitudinal cognitive outcomes, controlling for age, education, and max VO₂ change as a measure of fitness.

RESULTS

In patients with SH in CH tracts, there was a significant interaction with the Trail Making Test (TMT) part A and part B over time. Patients without SH improved on average 16.6 and 15.0% on the TMT-A and TMT-B, respectively. Patients with SH on average showed no improvements in either TMT-A or TMT-B over time. There were no significant differences in other cognitive measures.

CONCLUSION

These results suggest that CAD patients with SH in CH tracts improve less than those without SH in CH tracts, over 48 weeks of cardiac rehabilitation. Thus, SH in CH tracts may contribute to longitudinal cognitive decline following a cardiac event and may represent a vascular risk factor of cognitive decline. © 2017 The Authors. International Journal of Geriatric Psychiatry Published by John Wiley & Sons Ltd.

Comparing the neuropsychological profiles of mild dementia with Lewy bodies and mild Alzheimer's disease

BACKGROUND

The present study was conducted to detect neuropsychological differences and to identify discriminators between mild dementia with L ewy bodies (DLB ) and mild A lzheimer's disease (AD ).

METHODS

The present study included 37 mild DLB patients, 48 mild AD patients, and 80 healthy elderly individuals. A comprehensive battery of neuropsychological tests was administrated to assess their cognitive function. Linear stepwise discriminant analysis was used to identify the neuropsychological measures with values that could differentiate between mild DLB and mild AD .

RESULTS

The mild DLB group had greater impairments in attention, executive function, and visuospatial ability, while mild AD patients performed significantly worse on memory tests. Linear stepwise discriminant analysis indicated that the M emory and E xecutive S creening's 5-min delayed recall test was the best neuropsychological discriminator between mild DLB and mild AD .

CONCLUSIONS

Different patterns of cognitive impairment facilitate the differentiation of mild DLB from mild AD . For patients with mild dementia, better performance on the M emory and E xecutive S creening's 5-min delayed recall test suggests that the diagnosis is more likely DLB than AD .

Longitudinal evaluation of Tau-P301L transgenic mice reveals no cognitive impairments at 17 months of age

Introduction

Tau is a microtubule-associated binding protein implicated in neurodegenerative tauopathies, including frontotemporal dementia (FTD) and Alzheimer's disease (AD). These diseases result in the intracellular accumulation of hyperphosphorylated tau in the form of neurofibrillary tangles, the presence of which is associated with cognitive deficits.

Methods

We conducted a longitudinal behavioral study to provide a profile of the TgTau(P301L)23027 transgenic mouse in multiple cognitive domains across multiple ages. P301L is the tau mutation most frequently observed in patients with frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17) and this mouse model recapitulates the progressive development of glial and neurofibrillary tangles, and associated cerebral atrophy observed in patients. We examined frontal cortex-dependent executive function and attention with the touchscreen 5-choice serial reaction time test (5-CSRTT) and assessed the function of temporal cortical structures using novel object recognition (OR).

Results

Despite using sensitive tasks, there were no apparent changes in executive function, attention, or recognition memory in the transgenic mice from 5 to 17 months of age.

Conclusions

This study represents the first comprehensive longitudinal analysis of cognition in the TgTauP301L mouse model and suggests that this model is not ideal for studying early attention and recognition memory impairments associated with tauopathy. However, spatial and object recognition memory impairments were observed during follow-up assessments when the mice were 18 and 21 months, respectively. These impairments are consistent with previous publications, and with a dementia-like phenotype in these mice when aged.

Diagnostic Utility of the Shortened Version of the Wisconsin Card Sorting Test in Patients With Sporadic Late Onset Alzheimer Disease

BACKGROUND

The classic version of the Wisconsin Card Sorting Test (WCST) consists of correctly sorting 128 cards according to changing sorting criteria. Its application is costly in terms of the time employed, with all the negative consequences this entails (decrease in motivation, frustration, and fatigue).

METHOD

The main objective of this study was to test the usefulness of the shortened version of the WCST as compared to the full test by analyzing the equivalence between the two decks comprising the full 128-card version on a sample of patients diagnosed with sporadic late onset Alzheimer disease (SLOAD) and to check its clinical usefulness.

RESULTS

The variables showed equivalence between the two decks and their ability to differentiate between the control group (CG) and the Alzheimer disease (AD) group.

CONCLUSION

The scores obtained suggest equivalence between decks and that the application of only the first deck is sufficient.

Psychosocial or clinico-demographic factors related to neuropsychiatric symptoms in patients with Alzheimer's disease needing interventional treatment: analysis of the CATIE-AD study

OBJECTIVE

This study sought to determine psychosocial and clinico-demographic factors related to each symptomatic cluster (i.e., aggressiveness, psychosis, apathy/eating problems, and emotion/disinhibition) of neuropsychiatric symptoms (NPSs) in patients with Alzheimer's disease (AD) needing interventional treatment against their agitation or psychotic symptoms. These clusters were classified from 12 Neuropsychiatric Inventory (NPI) subscores in our previous study using the Clinical Antipsychotic Trials of Intervention Effectiveness-Alzheimer's Disease (CATIE-AD) dataset.

METHODS

Based on clinical data from 421 AD outpatients with agitation or psychotic symptoms needed interventional treatment enrolled in the CATIE-AD, we conducted logistic regression analyses to examine the relationships between each symptomatic cluster and three psychosocial (marital status, residence, and caregivers' burden) and nine clinico-demographic (age, gender, education year, general cognition, activity of daily living [ADL], general medical health, race, and intake of anti-dementia drugs or psychotropics) factors.

RESULTS

While no factor contributed to aggressiveness, psychosis was associated with several clinico-demographic factors: female gender, non-Caucasian race, and lower cognitive function. Apathy/eating problems was associated with more severe caregiver burden, living in one's own home, lower ADL level, and male gender, while emotion/disinhibition was predicted by more severe caregiver burden, lower education level, not-married status, and younger age.

CONCLUSIONS

Among the four NPS clusters, apathy/eating problems and emotion/disinhibition were associated with psychosocial as well as clinico-demographic factors in AD patients with psychotic symptoms or agitation needed interventional treatment. Copyright © 2016 John Wiley & Sons, Ltd.

The involvement of alpha oscillations in voluntary attention directed towards encoding episodic memories

Forming episodic memories is often driven by top-down processes of allocating attention towards voluntarily remembering the details of an episode. This attention orientation is needed to make sure that information is encoded for later remembering. Here we designed an episodic long-term memory (LTM) EEG experiment where we examined brain oscillatory activity associated with attention allocation towards the temporal link between an item and its context. The remembering of this temporal conjunction is crucial for item-context binding and hence for the formation of episodic memories. Participants saw a background picture and a word in a central position on a computer screen and were instructed to memorise (a) the picture only, (b) the word, (c) both individually (i.e. ignoring their co-occurrence) and (d) both with them being presented together. Attention allocation towards item-context binding was associated with oscillatory alpha desynchronization in the upper alpha band (10-13 Hz) over dominantly left posterior brain areas. The results highlight the role of alpha desynchronization in voluntary attention allocation towards the temporal conjunction of item and its context in episodic binding and the involvement of posterior brain areas. The pattern of results suggest that they most likely reflect additional visual processes recruited by attentional mechanisms and do not tap into neural processes of item-context binding per se. Moreover, it indicates that the involvement of alpha oscillations in cognitive processes may be more complex.

Cerebral metabolic correlates of attention networks in Alzheimer's Disease: A study of the Stroop

Patients with Alzheimer's Disease (AD) show difficulties with attention. Cognitive neuroscience models posit that attention can be broken down into alerting, orienting, and executive networks. We used the Stroop Color-Word test to interrogate the neural correlates of attention deficits in AD. We hypothesized that the Word, Color, and Color-Word conditions of the Stroop would all tap into the alerting and orienting networks. The Color-Word condition would additionally tap into the executive network. A ratio of Color-Word to Color naming performance would isolate the executive network from the others. To identify the neural underpinnings of attention in AD we correlated performance on the Stroop with brain metabolic activity. Sixty-six patients with probable AD completed [18F] fluorodeoxyglucose PET scanning and neuropsychological testing. Analysis was conducted with SPM12 (p<0.001 uncorrected, extent threshold 50 voxels). Performance on the Word, Color, and Color-Word conditions directly correlated with metabolic rate in right inferior parietal lobules/intraparietal sulci. The Color-Word/Color ratio revealed associations with metabolic rate in right medial prefrontal cortex and insula/operculum. Overall findings were largely consistent with the hypothesized neuroanatomical substrates of the alerting, orienting, and executive networks. As such, attention deficits in AD reflect compromise to multiple large-scale networks.

False Memories in Alzheimer's Disease: Intact Semantic Priming But Impaired Production of Critical Lures

Objectives

This study explores the activation of the critical lure (CL) and its production in Deese-Roediger-McDermott (DRM) tasks in Alzheimer's disease and aging. In a previous lexical decision task including DRM lists, we showed that the activation of the CL occurs normally in Alzheimer's patients. Here, we reproduce this study and add a production (DRM) task in order to compare both processes in the same groups of participants.

Method

Eighteen older adults and 20 Alzheimer's patients performed a conventional DRM task, followed by a lexical decision task with DRM lists intermixed with neutral words and nonwords.

Results

Analyses indicated that Alzheimer's patients produced significantly fewer CLs than older participants in the DRM task, but that they showed, like older adults, shorter lexical decision latencies for CLs than for other types of words.

Discussion

This study provides evidence that the low production of CLs regularly documented in Alzheimer's patients in the DRM paradigm is not necessarily explained by their nonactivation. The results are discussed in the light of the hypothesis of a rapid disappearance of the episodic mnemonic trace of the CLs in Alzheimer's patients.

Sensitivity of the Mini-Mental State Examination, Montreal Cognitive Assessment and the Addenbrooke's Cognitive Examination III to everyday activity impairments in dementia: an exploratory study

OBJECTIVE

The Mini-Mental State Examination (MMSE) is one of the most frequently used cognitive measures for dementia severity and linked to deficits in everyday functioning. Recently, the Montreal Cognitive Assessment (MoCA) and the Addenbrooke's Cognitive Examination III (ACE-III) increasingly substitute for the MMSE. However, there are no specific cutoffs in the ACE-III for mild dementia. The objectives of this exploratory study were to assess the sensitivity of each scale to everyday functioning and to examine the cutoffs between mild and moderate dementia on the ACE-III.

METHODS

People with mild dementia completed the MMSE, MoCA and ACE-III, whilst informal carers completed the Revised Interview for Deteriorations in Daily Living Activities for Dementia to rate their relative's initiative and performance of instrumental activities of daily living and the Katz activities of daily living scale. Data were analysed using correlation analysis, raw score comparisons, Cohen's kappa and receiver operating characteristics analysis.

RESULTS

Thirty-three dyads completed the measures. The ACE-III was the most sensitive tool for everyday functioning performance, whilst its language subscale was specifically related to initiation of activities. The most suitable cutoff on the ACE-III between mild and moderate dementia was 61.

CONCLUSIONS

Findings suggest the ACE-III more efficiently identifies everyday functional impairments. Further research is required to confirm these exploratory analyses of the cutoff between mild and moderate dementia on the ACE-III. Both functional impairment and stage of dementia are needed in the diagnostic process and in the clinical assessment of people with dementia. Copyright © 2016 John Wiley & Sons, Ltd.

Altered Behavioral and Autonomic Pain Responses in Alzheimer's Disease Are Associated with Dysfunctional Affective, Self-Reflective and Salience Network Resting-State Connectivity

While pain behaviors are increased in Alzheimer's disease (AD) patients compared to healthy seniors (HS) across multiple disease stages, autonomic responses are reduced with advancing AD. To better understand the neural mechanisms underlying these phenomena, we undertook a controlled cross-sectional study examining behavioral (Pain Assessment in Advanced Dementia, PAINAD scores) and autonomic (heart rate, HR) pain responses in 24 HS and 20 AD subjects using acute pressure stimuli. Resting-state fMRI was utilized to investigate how group connectivity differences were related to altered pain responses. Pain behaviors (slope of PAINAD score change and mean PAINAD score) were increased in patients vs.

CONTROLS

Autonomic measures (HR change intercept and mean HR change) were reduced in severe vs. mildly affected AD patients. Group functional connectivity differences associated with greater pain behavior reactivity in patients included: connectivity within a temporal limbic network (TLN) and between the TLN and ventromedial prefrontal cortex (vmPFC); between default mode network (DMN) subcomponents; between the DMN and ventral salience network (vSN). Reduced HR responses within the AD group were associated with connectivity changes within the DMN and vSN-specifically the precuneus and vmPFC. Discriminant classification indicated HR-related connectivity within the vSN to the vmPFC best distinguished AD severity. Thus, altered behavioral and autonomic pain responses in AD reflects dysfunction of networks and structures subserving affective, self-reflective, salience and autonomic regulation.

Visualizing Hyperactivation in Neurodegeneration Based on Prefrontal Oxygenation: A Comparative Study of Mild Alzheimer's Disease, Mild Cognitive Impairment, and Healthy Controls

Background: Cognitive performance is relatively well preserved during early cognitive impairment owing to compensatory mechanisms. Methods: We explored functional near-infrared spectroscopy (fNIRS) alongside a semantic verbal fluency task (SVFT) to investigate any compensation exhibited by the prefrontal cortex (PFC) in Mild Cognitive Impairment (MCI) and mild Alzheimer's disease (AD). In addition, a group of healthy controls (HC) was studied. A total of 61 volunteers (31 HC, 12 patients with MCI and 18 patients with mild AD) took part in the present study. Results: Although not statistically significant, MCI exhibited a greater mean activation of both the right and left PFC, followed by HC and mild AD. Analysis showed that in the left PFC, the time taken for HC to achieve the activation level was shorter than MCI and mild AD (p = 0.0047 and 0.0498, respectively); in the right PFC, mild AD took a longer time to achieve the activation level than HC and MCI (p = 0.0469 and 0.0335, respectively); in the right PFC, HC, and MCI demonstrated a steeper slope compared to mild AD (p = 0.0432 and 0. 0107, respectively). The results were, however, not significant when corrected by the Bonferroni-Holm method. There was also found to be a moderately positive correlation (R = 0.5886) between the oxygenation levels in the left PFC and a clinical measure [Mini-Mental State Examination (MMSE) score] in MCI subjects uniquely. Discussion: The hyperactivation in MCI coupled with a better SVFT performance may suggest neural compensation, although it is not known to what degree hyperactivation manifests as a potential indicator of compensatory mechanisms. However, hypoactivation plus a poorer SVFT performance in mild AD might indicate an inability to compensate due to the degree of structural impairment. Conclusion: Consistent with the scaffolding theory of aging and cognition, the task-elicited hyperactivation in MCI might reflect the presence of compensatory mechanisms and hypoactivation in mild AD could reflect an inability to compensate. Future studies will investigate the fNIRS parameters with a larger sample size, and their validity as prognostic biomarkers of neurodegeneration.

Developmental suppression of forebrain trkA receptors and attentional capacities in aging rats: A longitudinal study

Basal forebrain (BF) cholinergic neurons innervating the cortex regulate cognitive, specifically attentional, processes. Cholinergic atrophy and cognitive decline occur at an accelerated pace in age-related neurodegenerative disorders such as Alzheimer's disease; however, the mechanism responsible for this phenomenon remains unknown. Here we hypothesized that developmental suppression of nerve growth factor signaling, mediated via tropomyosin-related kinase A (trkA) receptors, would escalate age-related attentional vulnerability. An adeno-associated viral vector expressing trkA shRNA (AAV-trkA) was utilized to knockdown trkA receptors in postnatal rats at an ontogenetic time point when cortical cholinergic inputs mature, and the impact of this manipulation on performance was assessed in animals maintained on an operant attention task throughout adulthood and until old (24 months) age. A within-subject comparison across different time points illustrated a gradual age-related decline in attentional capacities. However, the performance under baseline and distracted conditions did not differ between the AAV-trkA-infused and animals infused with a vector expressing shRNA against the control protein luciferase at any time point. Additional analysis of cholinergic measures conducted at 24 months showed that the capacity of cholinergic terminals to release acetylcholine following a depolarizing stimulus, cortical cholinergic fiber density and BF cholinergic cell size remained comparable between the two groups. Contrary to our predictions, these data indicate that developmental BF trkA disruption does not impact age-related changes in attentional functions. It is possible that life-long engagement in cognitive activity might have potentially rescued the developmental insults on the cholinergic system, thus preserving attentional capacities in advanced age.

The importance of sustained attention in early Alzheimer's disease

INTRODUCTION

There is conflicting evidence regarding impairment of sustained attention in early Alzheimer's disease (AD). We examine whether sustained attention is impaired and predicts deficits in other cognitive domains in early AD.

METHODS

Fifty-one patients with early AD (MMSE > 18) and 15 healthy elderly controls were recruited. The sustained attention to response task (SART) was used to assess sustained attention. A subset of 25 patients also performed tasks assessing general cognitive function (ADAS-Cog), episodic memory (Logical memory scale, Paired Associates Learning), executive function (verbal fluency, grammatical reasoning) and working memory (digit and spatial span).

RESULTS

AD patients were significantly impaired on the SART compared to healthy controls (total error β = 19.75, p = 0.027). SART errors significantly correlated with MMSE score (Spearman's rho = -0.338, p = 0.015) and significantly predicted deficits in ADAS-Cog (β = 0.14, p = 0.004).

DISCUSSIONS

Patients with early AD have significant deficits in sustained attention, as measured using the SART. This may impair performance on general cognitive testing, and therefore should be taken into account during clinical assessment, and everyday management of individuals with early AD. Copyright © 2016 John Wiley & Sons, Ltd.

Altered functional connectivity in patients with post-stroke memory impairment: A resting fMRI study

Post-stroke memory dysfunction (PMD) is one of the most common forms of cognitive impairment among stroke survivors. However, only a limited number of studies have directly investigated the neural mechanisms associated with memory decline. The aim of the present study was to identify dynamic changes in the functional organization of the default mode network (DMN) and the dorsal attention network of patients with PMD. A total of 27 patients with PMD who experienced a stroke in the right hemisphere were enrolled in the current study, along with 27 healthy control subjects matched by age, sex, and educational level. A behavioral examination and functional magnetic resonance imaging scan were performed. The data were analyzed using an independent component analysis method. The results revealed a significantly increased functional connectivity between the DMN and prefrontal cortex (left middle/inferior frontal and left precentral gyri), temporal regions (left superior temporal gyrus), and bilateral and posterior cingulate gyri/precuneus (P<0.001). There was also a significantly decreased functional connectivity between the DMN and right middle temporal gyrus, left uvula, and right inferior parietal lobule, and between the dorsal attention network and prefrontal cortex (left precentral/inferior and right inferior/middle frontal gyri), right inferior parietal gyrus, and right insula (P<0.001). These results suggest that the stroke affected both the lesioned and contralesional hemispheres. The prefrontal cortex, temporal regions, insula, and posterior cingulate gyrus/precuneus serve a crucial role in memory processing.

A short cut to the past: Cueing via concrete objects improves autobiographical memory retrieval in Alzheimer's disease patients

Older adults diagnosed with Alzheimer's disease (AD) have difficulties accessing autobiographical memories. However, this deficit tends to spare memories dated to earlier parts of their lives, and may partially reflect retrieval deficits rather than complete memory loss. Introducing a novel paradigm, the present study examines whether autobiographical memory recall can be improved in AD by manipulating the sensory richness, concreteness and cultural dating of the memory cues. Specifically, we examine whether concrete everyday objects historically dated to the participants' youth (e.g., a skipping rope), relative to verbal cues (i.e., the verbal signifiers for the objects) facilitate access to autobiographical memories. The study includes 49 AD patients, and 50 healthy, older matched control participants, all tested on word versus object-cued recall. Both groups recalled significantly more memories, when cued by objects relative to words, but the advantage was significantly larger in the AD group. In both groups, memory descriptions were longer and significantly more episodic in nature in response to object-cued recall. Together these findings suggest that the multimodal nature of the object cues (i.e. vision, olfaction, audition, somatic sensation) along with specific cue characteristics, such as time reference, texture, shape, may constrain the retrieval search, potentially minimizing executive function demands, and hence strategic processing requirements, thus easing access to autobiographical memories in AD.

Financial capacity in dementia: a systematic review

OBJECTIVES

Financial capacity (FC) refers to a set of cognitively mediated abilities related to one's competency to manage propriety and income. Identifying intact from impaired FC in older persons with dementia is a growing concern in geriatric practice, but the best methods to assess this function still need to be determined. This study aims to review data on FC in dementia and on instruments used to assess this domain of capacity.

METHODS

Database search was performed in Medline, ISI Web of Knowledge, LILACS and PsycINFO. Studies that objectively assessed FC in dementia of any etiology were included.

RESULTS

Of a total of 125 articles, 10 were included. Mild Alzheimer's Disease (AD) was associated with impaired complex FC abilities, namely checkbook management, bank statement management and financial judgment, but simple FC skills were preserved. Moderate AD was associated with impairment in all domains of FC. The Financial Capacity Instrument (FCI) was applied in most of the selected studies and correlated with neuropsychological and neuroimaging variables.

CONCLUSIONS

Early dementia is associated with partially preserved FC. More validation studies using objective and evidence-based FC assessment tools, such as the FCI, are still needed.

Exploration of verbal repetition in people with dementia using an online symptom-tracking tool

BACKGROUND

Online tools can be used by people with dementia and their caregivers to self-identify and track troubling symptoms, such as verbal repetition. We aimed to explore verbal repetition behaviors in people with dementia.

METHODS

Participants were recruited via an online resource for people with dementia and their caregivers. Respondents were instructed to complete information about symptoms that are most important to them for tracking over time. In this cross-sectional study, we analyzed data pertaining to individuals with dementia who had at least three symptoms selected for tracking.

RESULTS

Of the 3,573 participants who began a user profile, 1,707 fulfilled criteria for analysis. Verbal repetition was identified as a treatment target in 807 respondents (47.3%). Verbal repetition was more frequent in individuals with mild dementia compared to those with moderate and severe dementia (57.2% vs. 36.0% and 39.9%, p < 0.01) and in those with Alzheimer's disease versus other dementias (65.2% vs. 29.7%, p < 0.001). Repetitive questioning was the most frequent type of verbal repetition (90.5% of individuals with verbal repetition). Verbal repetition was most strongly associated with difficulties operating gadgets/appliances (OR 3.65, 95%CI: 2.82-4.72), lack of interest and/or initiative (3.52: 2.84-4.36), misplacing or losing objects (3.25: 2.64-4.01), and lack of attention and/or concentration (2.62: 2.12-3.26).

CONCLUSIONS

Verbal repetition is a common symptom in people at all stages of dementia but is most commonly targeted for monitoring and treatment effects in its mild stage. Much research is required to further elucidate the underlying mechanisms and the effect of different treatment strategies.

Mitophagy and Alzheimer's Disease: Cellular and Molecular Mechanisms

Neurons affected in Alzheimer's disease (AD) experience mitochondrial dysfunction and a bioenergetic deficit that occurs early and promotes the disease-defining amyloid beta peptide (Aβ) and Tau pathologies. Emerging findings suggest that the autophagy/lysosome pathway that removes damaged mitochondria (mitophagy) is also compromised in AD, resulting in the accumulation of dysfunctional mitochondria. Results in animal and cellular models of AD and in patients with sporadic late-onset AD suggest that impaired mitophagy contributes to synaptic dysfunction and cognitive deficits by triggering Aβ and Tau accumulation through increases in oxidative damage and cellular energy deficits; these, in turn, impair mitophagy. Interventions that bolster mitochondrial health and/or stimulate mitophagy may therefore forestall the neurodegenerative process in AD.

Age and Semantic Inhibition Measured by the Hayling Task: A Meta-Analysis

Objective

Cognitive aging is commonly associated with a decrease in executive functioning (EF). A specific component of EF, semantic inhibition, is addressed in the present study, which presents a meta-analytic review of the literature that has evaluated the performance on the Hayling Sentence Completion test in young and older groups of individuals in order to assess the magnitude of the age effect.

Method

A systematic search involving Web of Science, PsyINFO, PsychARTICLE, and MedLine databases and Google Scholar was performed. A total of 11 studies were included in this meta-analysis, encompassing a total of 887 participants; 440 young and 447 older adults. The effect sizes for group differences on four measures of the Hayling test, latency responses and error scores on the Automatic and Inhibition sections of the test were calculated using the Comprehensive Meta-Analysis software package.

Results

The results revealed large age effects for response latencies in both the Automatic (Hedges' g = 0.81) and Inhibitory conditions (Hedges' g = 0.98), though the latter two effect sizes did not differ from each other. In contrast, analysis of errors revealed a significant difference between the small effect seen in the Automatic condition (Hedges' g = 0.13) relative to the moderate effect seen in the Inhibition condition (Hedges' g = 0.55).

Conclusions

These results may be important for a better understanding of the inhibitory functioning in elderly individuals, although they should be interpreted with caution because of the limited number of studies in the literature to date.

Clinical Aspects of Alzheimer's Disease

Alzheimer's disease is the most common form of dementia accounting for 50-60% of all dementia cases. This chapter briefly reviews the history of Alzheimer's disease and provides an overview of the clinical syndromes associated with Alzheimer pathology and their associated neuroimaging findings. This chapter also reviews the neuropathology and genetics of Alzheimer's disease and concludes by discussing current work undertaken to identify suitable in vivo biomarkers for the disease.

Classification of Neuropsychiatric Symptoms Requiring Antipsychotic Treatment in Patients with Alzheimer's Disease: Analysis of the CATIE-AD Study

BACKGROUND

The Neuropsychiatric Inventory (NPI) comprises 12 items, which were conventionally determined by psychopathological symptoms of patients with dementia. The clinical rating scales with structured questionnaires have been useful to evaluate neuropsychiatric symptoms (NPSs) of patients with dementia over the past twenty year.

OBJECTIVE

The aim of this study was to classify the conventional NPSs in patients with Alzheimer's disease (AD) requiring antipsychotic treatment for their NPSs into distinct clusters to simplify assessment of these numerous symptoms.

METHODS

Twelve items scores (product of severity and frequency of each symptom) in the NPI taken from the baseline visit were classified into subgroups by principle component analysis using data from 421 outpatients with AD enrolled in the Clinical Antipsychotic Trials of Intervention Effectiveness-Alzheimer's Disease (CATIE-AD) Phase 1. Chi square tests were conducted to examine the co-occurrence of the subgroups.

RESULTS

We found four distinct clusters: aggressiveness (agitation and irritabilities), apathy and eating problems (apathy and appetite/eating disturbance), psychosis (delusions and hallucinations), and emotion and disinhibition (depression, euphoria, and disinhibition). Anxiety, aberrant motor behavior, and sleep disturbance were not included by these clusters. Apathy and eating problems, and emotion and disinhibition co-occurred (p = 0.002), whereas aggressiveness and psychosis occurred independent of the other clusters.

CONCLUSIONS

Four distinct category clusters were identified from NPSs in patients with AD requiring antipsychotic treatment. Future studies should investigate psychosocial backgrounds or risk factors of each distinct cluster, in addition to their longitudinal course over treatment intervention.

Enhancing attention in neurodegenerative diseases: current therapies and future directions

We all experience at least occasional lapses in attention but in some neurological conditions, loss of attention is pervasive and debilitating. Treating deficits in attention first requires an understanding of the neurobiology of attention, which we now understand to be a set of different cognitive processes. Cholinesterase inhibitors are already established as effective attentional enhancers used in the treatment of certain dementias. Other stimulant agents such as modafanil, amphetamine and methylphenidate have demonstrated limited success in healthy individuals where attention is already optimal and clinical trials in patients with neurological disease are sparse. Dietary and lifestyle changes are gaining increasing prominence, as are experimental treatments such as deep brain stimulation and transcranial magnetic stimulation. As the therapeutic arsenal widens, clinicians will be able to match specific treatments to selective deficits in attention, giving patients a tailored management plan. Here we review common diseases that impair attention and emphasise how an understanding of attentional processing within the brain might lead to improved therapeutic strategies.

Omega-3 Fatty Acids, Depressive Symptoms, and Cognitive Performance in Patients With Coronary Artery Disease: Analyses From a Randomized, Double-Blind, Placebo-Controlled Trial

This trial investigated the efficacy of omega-3 polyunsaturated fatty acid (n-3 PUFA) treatment for improving depressive symptoms and cognitive performance in patients with coronary artery disease (CAD) participating in cardiac rehabilitation. Patients with CAD aged 45 to 80 years were randomized to receive either 1.9-g/d n-3 PUFA treatment or placebo for 12 weeks. Depressive symptoms were measured using the Hamilton Depression Rating Scale (HAM-D, primary outcome) and the Beck Depression Inventory II (BDI-II). Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria were used to identify a depressive episode at baseline. Cognitive performance was measured using a standardized battery for vascular cognitive impairment. In 92 patients (age, 61.7 ± 8.7 y; 76% male, 40% depressed; HAM-D, 6.9 ± 5.9; BDI-II, 12.3 ± 10.9; n = 45 n-3 PUFA, n = 47 placebo), depression decreased (HAM-D, F3,91 = 2.71 and P = 0.049; BDI-II, F3,91 = 6.24 and P < 0.01), and cognitive performance improved (attention/processing speed, F1,91 = 5.57, P = 0.02; executive function, F1,91 = 14.64, P < 0.01; visuospatial memory, F1,91 = 4.01, P = 0.04) over cardiac rehabilitation. Omega-3 PUFA treatment increased plasma eicosapentaenoic acid (F1,29 = 33.29, P < 0.01) and docosahexaenoic acid (F1,29 = 15.29, P < 0.01) concentrations but did not reduce HAM-D (F3,91 = 1.59, P = 0.20) or BDI-II (F3,91 = 0.46, P = 0.50) scores compared with placebo. Treatment did not improve cognitive performance; however, n-3 PUFAs significantly increased verbal memory compared with placebo in a subgroup of nondepressed patients (F1,54 = 4.16, P = 0.04). This trial suggests that n-3 PUFAs do not improve depressive and associated cognitive symptoms in those with CAD. The possible benefits of n-3 PUFAs for verbal memory may warrant investigation in well-powered studies.

The Diagnosis of Delirium Superimposed on Dementia: An Emerging Challenge

Delirium occurring in patients with dementia is referred to as delirium superimposed on dementia (DSD). People who are older with dementia and who are institutionalized are at increased risk of developing delirium when hospitalized. In addition, their prior cognitive impairment makes detecting their delirium a challenge. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition and the International Statistical Classification of Diseases and Related Health Problems, 10th Revision are considered the standard reference for the diagnosis of delirium and include criteria of impairments in cognitive processes such as attention, additional cognitive disturbances, or altered level of arousal. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition and the International Statistical Classification of Diseases and Related Health Problems, 10th Revision does not provide guidance regarding specific tests for assessment of the cognitive process impaired in delirium. Importantly, the assessment or inclusion of preexisting cognitive impairment is also not addressed by these standards. The challenge of DSD gets more complex as types of dementia, particularly dementia with Lewy bodies, which has features of both delirium and dementia, are considered. The objective of this article is to critically review key elements for the diagnosis of DSD, including the challenge of neuropsychological assessment in patients with dementia and the influence of particular tests used to diagnose DSD. To address the challenges of DSD diagnosis, we present a framework for guiding the focus of future research efforts to develop a reliable reference standard to diagnose DSD. A key feature of a reliable reference standard will improve the ability to clinically diagnose DSD in facility-based patients and research studies.

Alzheimer's Disease: Prototype of Cognitive Deterioration, Valuable Lessons to Understand Human Cognition

It is important for neurologists to become more familiar with neuropsychological evaluation for Alzheimer disease. The growth of this method in research, as an available, inexpensive, and noninvasive diagnostic approach, which can be administered even by non-specialist-trained examiners, makes this knowledge more necessary than ever. Such knowledge has a basic role in planning national programs in primary health care systems for prevention and early detection of Alzheimer disease. This is more crucial in developing countries, which have higher rates of dementia prevalence along with cardiovascular risk factors, lack of public knowledge about dementia, and limited social support. In addition compared to the neurological hard signs which are tangible and measurable, the concept of cognition seems to be more difficult for the neurologists to evaluate and for the students to understand. Dementia in general and Alzheimer's disease as the prototype of cognitive disorders specifically, play an important role to explore all domains of human cognition through its symptomatology and neuropsychological deficits.

Rule induction performance in amnestic mild cognitive impairment and Alzheimer's dementia: examining the role of simple and biconditional rule learning processes

INTRODUCTION

Rule induction tests such as the Wisconsin Card Sorting Test require executive control processes, but also the learning and memorization of simple stimulus-response rules. In this study, we examined the contribution of diminished learning and memorization of simple rules to complex rule induction test performance in patients with amnestic mild cognitive impairment (aMCI) or Alzheimer's dementia (AD).

METHOD

Twenty-six aMCI patients, 39 AD patients, and 32 control participants were included. A task was used in which the memory load and the complexity of the rules were independently manipulated. This task consisted of three conditions: a simple two-rule learning condition (Condition 1), a simple four-rule learning condition (inducing an increase in memory load, Condition 2), and a complex biconditional four-rule learning condition-inducing an increase in complexity and, hence, executive control load (Condition 3).

RESULTS

Performance of AD patients declined disproportionately when the number of simple rules that had to be memorized increased (from Condition 1 to 2). An additional increment in complexity (from Condition 2 to 3) did not, however, disproportionately affect performance of the patients. Performance of the aMCI patients did not differ from that of the control participants. In the patient group, correlation analysis showed that memory performance correlated with Condition 1 performance, whereas executive task performance correlated with Condition 2 performance.

CONCLUSIONS

These results indicate that the reduced learning and memorization of underlying task rules explains a significant part of the diminished complex rule induction performance commonly reported in AD, although results from the correlation analysis suggest involvement of executive control functions as well. Taken together, these findings suggest that care is needed when interpreting rule induction task performance in terms of executive function deficits in these patients.

Functional-structural degeneration in dorsal and ventral attention systems for Alzheimer's disease, amnestic mild cognitive impairment

Growing evidence of attention related failures in patients with amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD) has already been proposed by previous studies. However, previous studies lacked of systematic investigation on the functional and structural substrates for attention function for patients with AD and aMCI. In this work, we investigated the functional connectivity and gray matter density in dorsal and ventral attention networks (DAN, VAN) of normal participants (n = 15) and patients with aMCI (n = 12) and AD (n = 16) by applying group independent component analysis (ICA) and voxel-based morphometry (VBM) analysis. Using ICA, we extracted the functional patterns of DAN and VAN which are respectively responsible for the "top-down" attention process and "bottom-up" process. One-way analysis of variance (ANOVA) revealed significant group-differed functional connectivity in bilateral frontal eye fields (FEF) area and intraparietal sulcus (IPS) area, as well as posterior cingulate cortex and precuneus in the dorsal system. With regard to the ventral system, group-effects were significantly focused in right orbital superior/middle frontal gyrus, right inferior parietal lobule, angular gyrus, and supramarginal gyrus around the temporal-parietal junction area. Post hoc cluster-level comparisons revealed totally impaired functional substrates for both attentional networks for patients with AD, whereas selectively impaired attention systems for patients with aMCI with impaired functional patent of DAN but preserved functional pattern of VAN. Correspondingly, VBM analysis revealed gray matter loss in right ventral and dorsal frontal cortex was in the AD group, whereas preserved gray matter density was in aMCI, even a little extent of expansion of gray matter density in several participants. Using multivariate regression analysis we found discrepant couplings of functional-structural degenerations between both patient groups. Specifically, positive coupling of structural-functional degeneration was found in right dorsal and ventral frontal cortex in the AD group, whereas inverse coupling in dorsal frontal cortex was found in the aMCI group. These findings suggested discrepant functional-structural degenerations in both attention systems between both patient groups, widening avenues to better understanding the attentional deficits in patients with aMCI and AD.

Assessment of Drivers with Alzheimer's Disease in High Demand Driving Situations: Coping with Intersections in a Driving Simulator

Intersections are one of the most complex and cognitively demanding driving situations. Individuals with dementia and, more precisely, Alzheimer's disease (AD), may face additional challenges negotiating intersections given the nature of their cognitive decline, which often includes deficits of attention. We developed a comprehensive evaluation scheme to assess simulated driving performance at intersections. The evaluation scheme captured all types of errors that could occur during preparation (i.e., prior to the intersection), execution (i.e., during the intersection), and recovery (i.e., after the intersection). Using the evaluation scheme, intersection behaviour in a driving simulator among 17 drivers with mild AD was compared to that of 21 healthy controls. The results indicated that across all types of intersections, mild AD drivers exhibited a greater number of errors relative to controls. Drivers with mild AD made the most errors during the preparation period leading up to the intersection. These findings present a novel approach to analyzing intersection behaviour and contribute to the growing body of research on dementia and driving.

Sensitivity and specificity of executive function tests for Alzheimer's disease

Decline in executive function (EF) occurs early in Alzheimer's disease (AD) and can interfere with daily functioning. Unfortunately, little is known about the relative ability of traditional EF tests to detect these cognitive changes. Given that timely diagnosis and intervention are essential to improving functional outcome in this population, our aim was to identify the specific EF measures that best differentiated mild dementia from normal aging. Thirty-one patients with mild AD and 31 controls were administered 7 EF tests. Findings indicated significant between-group differences on all measures except Wisconsin Card Sorting Test. The remaining 6 tests displayed fair to good accuracy discriminating between AD cases and controls. Only category fluency and Tower of London test remained in the final regression model that yielded the highest AUC of 0.90, which was not statistically different from that of either test alone. Overall, most of the tests employed were valid for assessing mild EF disturbances. Specifically, the two measures can be used in isolation for quick screening or in combination to facilitate a more in-depth evaluation of EF performance. This study contributes to clinical field by testifying to the validity of various EF tests to identify AD-related compromises in this cognitive domain.