Cognitive screening and neuropsychological assessment in early Alzheimer's disease

Impacts of AD-Related ABCA7 and CLU Variants on Default Mode Network Connectivity in Healthy Middle-Age Adults

Objective

To investigate the impact of Alzheimer’s disease (AD)-related risk gene (ATP-binding cassette A7-ABCA7 and Clusterin-CLU) on the functional connectivity pattern of default mode network (DMN) in healthy middle-age adults.

Methods

A total of 147 healthy middle-aged volunteers were enrolled in this study. All subjects completed MRI scans, neuropsychological assessments, and AD-related genotyped analysis. All subjects were divided into high, middle and low risk groups according to the score of risk genotypes, which included CLU (rs11136000, rs2279590, rs9331888, and rs9331949) and ABCA7 (rs3764650 and rs4147929). The genetic effects of CLU, ABCA7, and CLU × ABCA7 on DMN functional connectivity pattern were further explored. Moreover, the genetic effect of Apolipoprotein ε4 (APOEε4) was also considered. Finally, correlation analysis was performed between the signals of brain regions with genetic effect and neuropsychological test scores.

Results

Compared with the low-risk group, the high-risk group of CLU showed decreased functional connectivity in posterior cingulate cortex (PCC) and the left middle frontal cortex (P < 0.05, GRF correction). As for the interaction between the CLU and ABCA7, all the subjects were divided into high, middle, and low risk group; the middle-risk group was divided into CLU and ABCA7-dominated middle-risk group. The function connectivity pattern of DMN among the three or four groups were distributed in the bilateral medial prefrontal cortex (MPFC) and bilateral superior frontal gyrus (SFG) (P < 0.05, GRF correction). When APOEε4 carriers were excluded, the CLU-predominant middle-risk group displayed the decreased functional connectivity in MPFC when compared with the low-risk group, while ABCA7-prodominant middle-risk group displayed decreased functional connectivity in cuneus when compared with the high-risk group (all P < 0.05, GRF correction). The z values of left middle frontal cortex were positively correlated with the scores of Serial Dotting Test (SDT) in high-risk group of CLU, while z values of MPFC and cuneus were positively correlated to the scores of Montreal Cognitive Assessment (MoCA) in low-risk group of three or four groups.

Conclusion

The functional connectivity of MPFC-PCC might be modulated by the interaction of CLU and ABCA7. Moreover, APOEε4 might be interacted with ABCA7 and CLU modulation in the middle-aged carriers.

MS4A6A genotypes are associated with the atrophy rates of Alzheimer's disease related brain structures

Membrane-spanning 4-domains, subfamily A, member 6A (MS4A6A) has been identified as susceptibility loci of Alzheimer's disease (AD) by several recent genome-wide association studies (GWAS), whereas little is known about the potential roles of these variants in the brain structure and function of AD. In this study, we included a total of 812 individuals from the Alzheimer's disease Neuroimaging Initiative (ADNI) database. Using multiple linear regression models, we found MS4A6A genotypes were strongly related to atrophy rate of left middle temporal (rs610932: Pc = 0.017, rs7232: Pc = 0.022), precuneus (rs610932: Pc = 0.015) and entorhinal (rs610932, Pc = 0.022) on MRI in the entire group. In the subgroup analysis, MS4A6A SNPs were significantly accelerated the percentage of volume loss of middle temporal, precuneus and entorhinal, especially in the MCI subgroup. These findings reveal that MS4A6A genotypes affect AD specific brain structures which supported the possible role of MS4A6A polymorphisms in influencing AD-related neuroimaging phenotypes.

An approach for estimating item sensitivity to within-person change over time: An illustration using the Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS-Cog)

When assessments are primarily used to measure change over time, it is important to evaluate items according to their sensitivity to change, specifically. Items that demonstrate good sensitivity to between-person differences at baseline may not show good sensitivity to change over time, and vice versa. In this study, we applied a longitudinal factor model of change to a widely used cognitive test designed to assess global cognitive status in dementia, and contrasted the relative sensitivity of items to change. Statistically nested models were estimated introducing distinct latent factors related to initial status differences between test-takers and within-person latent change across successive time points of measurement. Models were estimated using all available longitudinal item-level data from the Alzheimer's Disease Assessment Scale-Cognitive subscale, including participants representing the full-spectrum of disease status who were enrolled in the multisite Alzheimer's Disease Neuroimaging Initiative. Five of the 13 Alzheimer's Disease Assessment Scale-Cognitive items demonstrated noticeably higher loadings with respect to sensitivity to change. Attending to performance change on only these 5 items yielded a clearer picture of cognitive decline more consistent with theoretical expectations in comparison to the full 13-item scale. Items that show good psychometric properties in cross-sectional studies are not necessarily the best items at measuring change over time, such as cognitive decline. Applications of the methodological approach described and illustrated in this study can advance our understanding regarding the types of items that best detect fine-grained early pathological changes in cognition. (PsycINFO Database Record

[Creation and normalisation of a verbal episodic memory task in elderly adults: "GERIA-12"]

INTRODUCTION

Early damage to episodic memory encoding and consolidation processes has been demonstrated in dementia of the Alzheimer type. However, in the domain of verbal episodic memory assessment, there are few diagnostic tools adapted to the old and oldest old as far as ease of administration and accuracy of normative data are concerned. Classic tasks are either too effortful (like the free recall/cued recall of 16 items), not sensitive enough (like the 5 words test), or insufficiently accurate for people above 70 years old in terms of normative data.

AIM

The aim of this study was to develop a reduced task (in terms of number of items and number of trials) assessing verbal episodic memory in people aged between 70 and 89 years old.

METHODS

The task (GERIA-12) used the same procedure as the RL/RI-16 task but the list comprised only 12 words and there were only 2 learning trials. In order to assess consolidation processes, we included 2 delayed recall trials, one after 20 minutes and the other after 24 hours. We also calculated indexes adapted from the Item-Specific Deficit Approach developed by Wright et al., which has the advantage of providing measures specific to encoding, consolidation and retrieval processes. Standardization was done with data from 220 people aged between 70 and 89 years old and belonging to 3 education levels.

RESULTS

We obtained a significant effect of age and education level: scores decrease with age and increase with education. Norms have thus been calculated taking those two variables into consideration. Concerning the standardization, Barona method has been used for free recall scores while percentiles have been used for all other scores (total recall, free recall, encoding, consolidation and retrieval indexes). Normative data are also provided for intrusions and perseverations.

CONCLUSION

This new task allows encoding, consolidation and retrieval processes assessment in older people and has the following advantages: the procedure is more suitable (ease and time of administration), there are accurate normative data for old and oldest old people, and there are normative data for two delayed recalls (at 20 minutes and at 24 hours).

Meta-analysis of peripheral blood apolipoprotein E levels in Alzheimer's disease

Background

Peripheral blood Apolipoprotein E (ApoE) levels have been proposed as biomarkers of Alzheimer’s disease (AD), but previous studies on levels of ApoE in blood remain inconsistent. This meta-analysis was designed to re-examine the potential role of peripheral ApoE in AD diagnosis and its potential value as a candidate biomarker.

Methods

We conducted a systematic literature search of MEDLINE, EMBASE, the Cochrane library, and BIOSIS previews for case-control studies measuring ApoE levels in serum or plasma from AD subjects and healthy controls. The pooled weighted mean difference (WMD) and 95% confidence interval (CI) were used to estimate the association between ApoE levels and AD risk.

Results

Eight studies with a total of 2250 controls and 1498 AD cases were identified and analyzed. The pooled WMD from a random-effect model of AD participants compared with the healthy controls was −5.59 mg/l (95% CI: [−8.12, −3.06]). The overall pattern in WMD was not varied by characteristics of study, including age, country, assay method, publication year, and sample type.

Conclusions

Our meta-analysis supports a lowered level of blood ApoE in AD patients, and indicates its potential value as an important risk factor for AD. Further investigation employing standardized assay for ApoE measurement are still warranted to uncover the precise role of ApoE in the pathophysiology of AD.

Oestrogen alpha-receptor variant and two-year memory decline in midlife Australian women

OBJECTIVE

To prospectively examine the influence of the oestrogen-α receptor (ESR1)PvuII polymorphism on changes in memory performance over a 2-year period among 80 midlife postmenopausal Australian women.

METHODS

Healthy women aged 56-67 years were administered a battery of four memory (verbal and non-verbal) tasks at baseline and 2 years later.

RESULTS

Carriers of the ESR1 p allele had significantly greater declines in logical memory compared to participants with the PP genotype, independent of demographic characteristics (e.g. age), chronic illness (e.g. hypertension), sleep aid usage, hormone levels, apolipoprotein E e4 status and prospective changes in mood, smoking and alcohol consumption.

CONCLUSION

These findings provide preliminary evidence for larger and longer prospective trials that will be able to determine if the p allele of the ESR1PvuII polymorphism is a potential biomarker of logical memory decline among aging women.

Translation, cultural adaptation and psychometric evaluation of the Leganés cognitive test in a low educated elderly Brazilian population

OBJECTIVE: To validate the Leganés cognitive test (LCT) for cognitive screening in low educated elderly Brazilians. METHODS: The study sample was composed of 59 elderly residents from the city of Santa Cruz, in Brazil, with low schooling levels. Reliability was analyzed with a two-day interval between assessments, and concurrent validity was assessed using the Mini Mental State Examination (MMSE). RESULTS: According to the LCT, the prevalence of dementia was 11.8%. The scale items showed a moderate to strong correlation between domains (p<0.01), and inter-rater reliability exhibited ICC=0.81, 95%CI=0.72-0.88. The factor analysis resulted in two factors: memory and orientation. Interscale agreement was considered poor (k=-0.02), supporting the hypothesis of an educational impact on final MMSE scores. CONCLUSION: The results suggest that LCT has acceptable levels of reliability for use in low-educated Brazilian elderly.

Group therapy for patients with mild cognitive impairment and their significant others: results of a waiting-list controlled trial

BACKGROUND

Patients with mild cognitive impairment (MCI) have to deal with an uncertain prognosis and also face a multitude of memory-related problems and psychosocial consequences. A newly developed group programme proved to be feasible, however, it needed confirmation by a controlled study.

AIM

This controlled study evaluates this group therapy for MCI patients aimed to help them accept and manage the memory problems and the psychosocial consequences. The programme combines elements from psychoeducation, cognitive rehabilitation and cognitive-behavioural therapy.

PATIENTS AND METHODS

Ninety-three MCI patients received treatment, with 30 patients being first assigned to a waiting list, thus serving as their own control group. Pre- and post-treatment acceptance and helplessness were assessed using subscales of the Illness Cognition Questionnaire, while distress and general well-being were gauged with the Geriatric Depression Scale and subscales of the RAND-36.

RESULTS

Linear mixed model analyses showed that, relative to the controls, acceptance had increased more in the intervention group compared to the waiting-list period (p = 0.034). Distress and general well-being showed no changes. Treatment responders demonstrating a clinically significant effect on acceptance and two of three secondary outcome measures had higher baseline levels of helplessness and fewer self-reported memory complaints in daily life than patients who did not improve.

CONCLUSION

The intervention helped the patients deal better with their uncertain future in that they were overall better able to accept their condition, with especially the female patients showing a decrease in helplessness cognitions, although the effects were relatively small.

Short clinical assessments applicable to busy practices

Because biomarkers to detect Alzheimer’s disease (AD) have not yet been validated, physicians must rely on clinical assessments. The Research Committee of the American Neuropsychiatric Association recommended that the ideal cognitive screening instrument have the following characteristics: First, it should take <15 minutes to administer by a clinician at any level of training. Second, it should sample all major cognitive domains, including memory, attention/concentration, executive function, visual-spatial skills, language, and orientation. Third, it should be reliable, having adequate test-retest and inter-rater validity. Finally, it should be able to detect cognitive disorders commonly encountered by neuropsychiatrists.

The American Academy of Neurology Practice Parameters from 1994 and 2001 and the Canadian Consensus Guidelines on Dementia from 2007 recommend that physicians screen subjects with suspected dementia or mild cognitive impairment (MCI), since these patients are at increased risk for AD. Currently, there are no data on the utility of screening subjects who are asymptomatic.

The most commonly used brief cognitive tests are the Mini-Mental State Examination (MMSE), according to a survey conducted by the International Psychogeriatric Association (IPA) in 2006, followed by the clock-drawing test, the delayed-word recall, the verbal fluency test, the similarities test, and the trail-making test. Clinicians appraised these assessments as the most effective and easiest to administer (Slide 1).

High-yield, automated radiosynthesis of 2-(1-{6-[(2-[18F]fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene)malononitrile ([18F]FDDNP) ready for animal or human administration

The biomarker 2-(1-{6-[(2-[(18)F]fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene)malononitrile ([(18)F]FDDNP) is used as a positron emission tomography (PET) imaging probe for Alzheimer's disease and other neurodegenerative diseases. A high-yield and fully automated synthesis of [(18)F]FDDNP--along with the synthesis and characterization of non-radioactive FDDNP, a fluorescent probe derived from 2-(1,1-dicyanopropenyl-2)-6-dimethylaminonaphthalene (DDNP)--are reported. Radiofluorination of the tosyloxy precursor 2-{[6-(2,2-dicyano-1-methylvinyl)-2-naphthyl](methyl)amino}ethyl-4-methylbenzenesulfonate (DDNPTs) with K(18)F/Kryptofix 2.2.2. yielded chemically (>99%) and radiochemically (>99%) pure [(18)F]FDDNP in high radiochemical yields (40-60%; n> 120), with specific activities ranging from 4 to 8 Ci/mumol at the end of synthesis (90 minutes). Both remote, semiautomated and automated synthesis procedures are described. Either approach provides a reliable method for production of large quantities (110-170 mCi from 500 mCi of [(18)F]fluoride) of [(18)F]FDDNP allowing for multiple PET experiments in the same day or for distribution of the tracer from a single cyclotron facility to PET imaging centers at various geographical distances.

Visualizing Pathology Deposits in the Living Brain of Patients with Alzheimer's Disease

One of the major neuropathological changes characteristic of Alzheimer's disease (AD) are deposits of beta-amyloid plaques and neurofibrillary tangles in neocortical and subcortical regions of the AD brain. The histochemical detection of these lesions in postmortem brain tissue is necessary for definitive diagnosis of AD. Methods for their in vivo detection would greatly aid the diagnosis of AD in early stages when neuronal loss and related functional impairment are still limited and also open the opportunity for effective therapeutic interventions. Positron emission tomography (PET) using an appropriate radiolabeled imaging probe with high binding affinity for these lesions is one of such techniques. We have developed 2-(1-{6-[(2-[F-18]fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene)malononitrile ([F-18]FDDNP), a naphthalene-based radiofluorinated PET imaging probe with binding affinity for amyloid and amyloid-like structures, and applied it for in vivo brain imaging of patients with Alzheimer's disease and cognitively normal controls with PET. Analysis of in vivo [F-18]FDDNP imaging data using Logan plot graphical analysis with the cerebellum as a reference region was performed, and the binding levels in several areas of neocortex were determined. We observed increased levels of [F-18]FDDNP binding in patients in several neocortical regions in Alzheimer's disease compared with the cerebellum. In contrast, control subjects have uniformly low levels of [F-18]FDDNP binding in all areas, which is comparable to that of cerebellum.

The traveling salesman problem as a new screening test in early Alzheimer's disease: an exploratory study. Visual problem-solving in AD

BACKGROUND AND AIMS

In the clinical setting, brief general mental status tests tend to detect early-stage Alzheimer's disease (AD) less well than more specific cognitive tests. Some preliminary information was collected on the diagnostic accuracy of the Traveling Salesman Problem (TSP) compared with the Mini-Mental State Examination (MMSE) in recognizing early AD from normal aging.

METHODS

Fifteen AD outpatients (mean +/- SD MMSE: 24.45 +/- 2.61) and 30 age- and education-matched controls were submitted in a single blind protocol to a paper-and-pencil visually-presented version of the TSP, containing a random array of 30 points (TSP30). The task consisted of drawing the shortest continuous path, passing through each point once and only once, and returning to the starting point. Path lengths for subjects' solutions were computed and compared with the optimal solution given by a specific evolutionary algorithm called GenD.

RESULTS

TP30 discriminated significantly better between AD subjects and controls (ROC curve AUC = 0.976; 95% CI 0.94-1.01) compared with the MMSE corrected for age and education (ROC curve AUC = 0.877; 95% CI 0.74-1.005). A path length of 478.2354, taken as "cut-off point", classified correctly subjects with a sensitivity of 93.3% and a specificity of 99.3%, whereas a score corrected for age and education of 25.85 on the MMSE had a sensitivity of 73.3% and a specificity of 96.7%.

CONCLUSIONS

The TSP seems to be particularly sensitive to early AD and independent of patient's age and educational level. The high diagnostic ability, simplicity, and independence of age and education make the TSP promising as a screening test for early AD.

Neuropsychological evaluation of mild cognitive impairment: three case reports

Recent research on mild cognitive impairment (MCI) has focused on the description of the disorder, its biological markers, and conversion rates to dementia. Studies of cognitive deficits in individuals who present with memory decline but do not fulfill criteria for dementia have analyzed baseline group data according to outcome diagnosis. The application of these findings to the individual person remains problematic. The current article presents three cases with a relatively isolated deficit in memory for word lists but better performance on other memory tests. Questions arising with regards to the MCI criteria are discussed in light of these case reports.

Validation of a short cognitive tool for the screening of dementia in elderly people with low educational level

AIM

To validate the 'Prueba Cognitiva de Leganés' (PCL) as a screening tool for cognitive impairment in elderly people with little formal education.

METHODS

The PCL is a simple cognitive test with 32 items that includes two scores of orientation and memory and a global score of 0-32 points. It was applied to a population sample of 527 elderly people over 70 with low educational level, who were independently diagnosed by consensus between two neurologists as having normal cognitive function, age associated cognitive decline (AACD, IPA-OMS criteria) or dementia (DSM-IV criteria). Individuals with severe visual or hearing defects and those who rejected the exam were excluded from the study. The PCL was validated in a sample of 375 individuals: 300 normal, 42 with AACD and 33 with dementia. The sensitivity, specificity, accuracy and likelihood ratios, as well as the ROC curves for dementia and for AACD-dementia, were calculated. The confounding effect of sociodemographic variables was assessed by logistic regression analysis and convergent validity by partial correlations of the PCL with other cognitive tests. Inter-rater reliability was evaluated with the intraclass correlation coefficient.

RESULTS

The PCL identified dementia (cut-off < or =22) and AACD-dementia (cut-off < or =26), with the following diagnostic parameters, respectively: sensitivity 93.9%-80%, specificity 94.7%-84.3%, positive likelihood ratio 17.8-5.1, negative likelihood ratio 0.06-0.24, and accuracy 94.6%-83.4%. The areas under the ROC curve were 0.985 (95% Confidence Intervals (CI) 0.967-0.995) and 0.904 (95% CI: 0.870-0.932) respectively. The intraclass correlation coefficient was 0.79 (0.74-0.83).

CONCLUSION

The PCL is a simple instrument, which is both valid and reliable, for the screening of dementia in population samples of individuals with low educational level. This instrument could be useful in primary health care.

Current awareness in geriatric psychiatry. Bibliography

In order to keep subscribers up-to-date with the latest developments in their field, John Wiley &amp: Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of geriatric psychiatry. Each bibliography is divided into 9 sections: 1 Books, Reviews &amp: Symposia; 2 General; 3 Assessment; 4 Epidemiology; 5 Therapy; 6 Care; 7 Dementia; 8 Depression; 9 Psychology. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted