Mild cognitive impairment subcategories depend on the source of norms

Normative Data for the Famous People Fluency Test in the Adult French-Quebec Population and Validation Study in Mild Cognitive Impairment and Alzheimer's Disease

OBJECTIVE

The production of words in verbal fluency tests relies heavily on executive functions and linguistic abilities. New tests such as the famous people fluency test can also be useful in clinical practice and research. This test, in which participants are asked to name so many famous people, has the potential to distinguish healthy individuals from participants with neurological disorders such as mild cognitive impairment or Alzheimer's disease.

METHOD

The aim of this study was to determine the psychometric validity of the test (Study 1) and to provide normative data in the adult population of French Quebec for the famous people fluency test (Study 2).

RESULTS

The results of the normative study, derived from a sample of 378 healthy individuals between the ages of 50 and 92, showed that age and educational level significantly influence performance on the test. Therefore, percentile ranks were calculated for performance on the famous people fluency test, stratified for these two variables. The results of Study 2 showed that the test differentiated the performance of healthy participants from the performance of participants with mild cognitive impairment or Alzheimer's disease. The results also showed that the famous people fluency test has adequate convergent validity, established with a semantic fluency test, and that the results showed good stability over time (test-retest validity).

CONCLUSION

Norms and psychometric data for the famous people fluency test will improve the ability of clinicians and researchers to better recognize executive and language impairments associated with pathological conditions.

Characterizing mild cognitive impairment to predict incident dementia in adults with bipolar disorder: What should the benchmark be?

Objective: Although mild cognitive impairment (MCI) is generally considered a risk state for dementia, its prevalence and association with dementia are impacted by the number of tests and cut-points used to assess cognition and define "impairment," and sources of norms. Here, we investigate how these methodological variations impact estimates of incident dementia in adults with bipolar disorder (BD), a vulnerable population with pre-existing cognitive deficits and increased dementia risk. Method: Neuropsychological data from 148 adults with BD and 13,610 healthy controls (HC) were drawn from the National Alzheimer's Coordinating Center. BD participants' scores were standardized against published norms and again using regression-based norms generated from HC within the same catchment area as individual BD patients ("site-specific norms"), varying the number of within-domain tests (one vs. two) and the cut-points (-1 vs. -1.5 SD) used to operationalize MCI. Results: Site-specific norms were more sensitive to incident dementia (88.6%-94.3%) than published norms (74.3%-88.6%), but only when using a "single test" definition of impairment. Specificity (22.1%-74.3%), accuracy (37.8%-68.9%), and positive predictive values (26.1%-38.3%) were overall poor. Applying a "single test" definition of impairment resulted in better negative predictive values using site-specific (92.3%-93.3%) than published norms (83.6%-86.2%), and a substantial increase in relative risk of incident dementia relative to published norms. Conclusions: Neuropsychologists should define "impairment" as scores below -1.0 or -1.5 SD on at least two within-domain measures when using published norms to interpret cognitive performance in adults with BD.

Normative Data for the Judgment of Line Orientation Test (Long and Short Forms) in the Quebec-French Population Aged between 50 and 89 Years

The Judgment of Line Orientation (JLO) Test of Benton assesses visuospatial processing without requiring motor skills. The test is frequently used in geriatric or brain-injured populations. As with other cognitive tests, performance on the JLO test may vary according to age, level of education, sex, and cultural background of individuals. The present study aimed to establish normative data for a short (15 items) and a long (30 items) form of the JLO. The sample for the short and long forms comprised 198 and 260 individuals, respectively, aged 50-89 years. All participants were French-speaking people from the province of Quebec, Canada. Using regression-based norming, the effects of age, years of formal education, and sex on JLO performance were estimated. The normative adjustment of the JLO short and long forms considered the weight of each predictor on test performance. Results indicated that JLO performance was positively associated with years of formal education and male sex, whereas it was negatively associated with age. Accordingly, normative data were generated using Z-scores and adjusted scaled scores derived from the regression equations. To conclude, the present norms will ease the detection of visuospatial impairment in French-Quebec middle-aged and older adults.

Normative data for the Tower of London (Drexel version) in the Quebec-French population aged between 50 and 88 years

The Tower of London (ToL) is a neuropsychological test used to assess several executive functions such as strategical reasoning, mental planning, and problem-solving. Like other cognitive tests, performance on the ToL can vary according to age, level of education, sex, and cultural background of individuals. The present study aimed to establish normative data for the Drexel version of the ToL among French-Quebec people aged 50 years and over. The normative sample consisted of 174 healthy individuals aged 50-88 years, all from the province of Quebec, Canada. Analyses were performed to estimate the associations between age, sex, and education level on one hand, and ToL performance, on the other hand. Results indicated that Total Execution Time was associated with age, whereas the Total Type II Errors and Total Rule Violation score (Type I + II Errors) were associated with both age and education level. All other scores were not significantly associated with the demographic characteristics of the participants. Since the distributions of the data were all skewed, the normative data are presented in the form of percentile ranks. To conclude, the present norms will ease the detection of executive impairments in French-Quebec middle-aged and older adults.

The Influence of Birth Cohorts on Future Cognitive Decline

BACKGROUND

Slowed rates of cognitive decline have been reported in individuals with higher cognitive reserve (CR), but interindividual discrepancies remain unexplained. Few studies have reported a birth cohort effect, favoring later-born individuals, but these studies remain scarce.

OBJECTIVE

We aimed to predict cognitive decline in older adults using birth cohorts and CR.

METHODS

Within the Alzheimer's Disease Neuroimaging Initiative, 1,041 dementia-free participants were assessed on four cognitive domains (verbal episodic memory; language and semantic memory; attention; executive functions) at each follow-up visit up to 14 years. Four birth cohorts were formed according to the major historical events of the 20th century (1916-1928; 1929-1938; 1939-1945; 1946-1962). CR was operationalized by merging education, complexity of occupation, and verbal IQ. We used linear mixed-effect models to evaluate the effects of CR and birth cohorts on rate of performance change over time. Age at baseline, baseline structural brain health (total brain and total white matter hyperintensities volumes), and baseline vascular risk factors burden were used as covariates.

RESULTS

CR was only associated with slower decline in verbal episodic memory. However, more recent birth cohorts predicted slower annual cognitive decline in all domains, except for executive functions. This effect increased as the birth cohort became more recent.

CONCLUSION

We found that both CR and birth cohorts influence future cognitive decline, which has strong public policy implications.

Normative data for the story recall subtest of the BEM-144 in the Quebec-French population aged 50 years and over

OBJECTIVE

The story recall subtest of the Batterie d'Efficience Mnésique (BEM-144) is a verbal episodic memory test that assesses immediate and episodic memory. Variables such as age, sex, and education level can impact performance on this type of memory test, as can cultural differences. Therefore, the purpose of this study was to establish normative data for the story recall subtest of the BEM-144 in the elderly French-Quebec population.

METHOD

The normative sample consisted of 260 healthy individuals aged 50-90 years, all from the province of Quebec, Canada. Analyses were performed to estimate the association between age, sex, and education level on one hand, and immediate and delayed recall performance, on the other hand.

RESULTS

The results show that all sociodemographic variables are significantly associated with story recall performance. Normative data are proposed in the form of regression equations.

CONCLUSIONS

Overall, these norms will be beneficial for the evaluation and detection of episodic memory impairment in middle-aged and older adults.

A Systematic Review and Comparison of Neurocognitive Features of Late-Life Attention-Deficit/Hyperactivity Disorder and Dementia With Lewy Bodies

OBJECTIVE

Attention-deficit/hyperactivity disorder (ADHD) in adulthood and dementia with Lewy bodies (DLB) share many cognitive and noncognitive similarities. The overlapping features between both disorders complicate differential diagnosis. The aim of the current systematic review was to compare patterns of neuropsychological profiles in older adults with ADHD and DLB.

METHOD

Of the 1989 ADHD-related articles and 1332 DLB-related articles screened, 3 ADHD and 25 DLB articles were retained for qualitative synthesis and review.

RESULTS

A synthesis of individual study findings revealed isolated working memory deficits for late-life ADHD, and performance deficits in areas of attention, memory, language, and visuoperceptual abilities for DLB. Results were limited by small samples and absence of data in some cognitive domains.

CONCLUSION

These initial findings support potentially unique neurocognitive profiles for ADHD in later life and DLB that would enable practitioners to differentially diagnose and appropriately treat older adults presenting with these phenotypically similar disorders.

TDQ-30-A New Color Picture-Naming Test for the Diagnostic of Mild Anomia: Validation and Normative Data in Quebec French Adults and Elderly

OBJECTIVE

A reduction in lexical access is observed in normal aging and a few studies also showed that this ability is affected in individuals with subjective cognitive decline. Lexical access is also affected very early in mild cognitive impairment as well as in major neurocognitive disorders. The detection of word-finding difficulties in the earliest stages of pathological aging is particularly difficult because symptoms are often subtle or mild. Therefore, mild anomia is underdiagnosed, mainly due to the lack of sensitivity of naming tests. In this article, we present the TDQ-30, a new picture-naming test designed to detect mild word-finding deficits in adults and elderly people.

METHOD

The article comprises three studies aiming at the development of the test (Study 1), the establishment of its validity and reliability (Study 2), and finally, the production of normative data for French-speaking adults and elderly people from Quebec (Study 3).

RESULTS

The results showed that the TDQ-30 has good convergent validity. Also, the TDQ-30 distinguished the performance of healthy controls from those of participants with mild cognitive impairment, Alzheimer's disease, and post-stroke aphasia. This suggests good discriminant validity. Finally, this study provides normative data computed from a study sample composed of 227 participants aged 50 years and over.

CONCLUSIONS

The TDQ-30 has the potential to become a valuable picture-naming test for the diagnosis of mild anomia associated with pathological aging.

Evaluating the Real-World Representativeness of Participants with Mild Cognitive Impairment in Canadian Research Protocols: a Comparison of the Characteristics of a Memory Clinic Patients and Research Samples

Background

Studies of mild cognitive impairment (MCI) employ rigorous eligibility criteria, resulting in sampling that may not be representative of the broader clinical population.

Objective

To compare the characteristics of MCI patients in a Calgary memory clinic to those of MCI participants in published Canadian studies.

Methods

Clinic participants included 555 MCI patients from the PROspective Registry of Persons with Memory SyMPToms (PROMPT) registry in Calgary. Research participants included 4,981 individuals with MCI pooled from a systematic literature review of 112 original, English-language peer-reviewed Canadian studies. Both samples were compared on baseline sociodemographic variables, medical and psychiatric comorbidities, and cognitive performance for MCI due to Alzheimer’s disease and Parkinson’s disease.

Results

Overall, clinic patients tended to be younger, more often male, and more educated than research participants. Psychiatric disorders, traumatic brain injury, and sensory impairment were commonplace in PROMPT (up to 83% affected) but > 80% studies in the systematic review excluded these conditions. PROMPT patients also performed worse on global cognition measures than did research participants.

Conclusion

Stringent eligibility criteria in Canadian research studies excluded a considerable subset of MCI patients with comorbid medical or psychiatric conditions. This exclusion may contribute to differences in cognitive performance and outcomes compared to real-world clinical samples.

Operationalizing Impaired Performance in Neuropsychological Assessment: A Comparison of the Use of Published Versus Sample-Based Normative Data for the Prediction of Dementia

OBJECTIVES

To compare the sensitivity, specificity, and predictive value of published versus sample-based norms to detect early dementia in the Uniform Data Set (UDS).

METHODS

The UDS was administered to 526 nondemented participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Baseline scores were standardized using published norms and healthy control data from ADNI corrected for age, education, and sex. Subjects obtaining two scores < -1 SD (determined separately using published and sample norms) were labeled "at risk for dementia." Both methods were compared on sensitivity, specificity, and positive/negative predictive value (PPV/NPV) for dementia at follow-up.

RESULTS

Risk scores derived from published data had 86.1% sensitivity, 62.0% specificity, 68.6% accuracy, 46.1% PPV, and 92.2% NPV. Those from sample norms were more sensitive (91.0%), less specific (52.9%), and less accurate (63.3%), with worse PPV (42.1%) and similar NPV (94.0%). Sample norms were better at identifying incident dementia cases with relatively lower education than those with higher education. Discrepancies between both methods were more common in women.

CONCLUSIONS

Sample norms are marginally more sensitive than published norms for predicting dementia, while published norms are slightly more accurate. Accuracy of risk estimates for women and those with lower education may be increased using locally generated norms.

Modified Wisconsin Card Sorting Test (M-WCST): Normative Data for the Lebanese Adult Population

The aim of this study was to generate normative data on the M-WCST in a Lebanese adult population and to examine the relationship between performance on this task and demographic variables. The sample consisted of 220 healthy adults aged between 18 and 64 years. Regression-based strategy was applied to generate normative data. The results showed a statistically significant effect of age and level of education on the M-WCST measures, whereas gender was not significant. Demographically calibrated percentiles and scaled scores were created. Finally, this study was the first to provide normative-adjusted tables for the M-WCST scores in Lebanon.

Young-Old City-Dwellers Outperform Village Counterparts in Attention and Verbal Control Tasks

Cognitive performance is dynamic and shaped by individual biological and environmental factors throughout life. In psychology, besides the effects of age, education, and other often studied factors, the complexity of the lived-in environment and urbanicity in that context are yet to be elucidated. In this observational cross-sectional study, we compare cognitive performance in standard neuropsychological tests in healthy older persons from three different types of settlements in the Czechia: the capital city of Prague, towns, and villages. The groups were equal in terms of the age-band (60–74 years), the distribution of gender, education, past and current leisure activities, and cognitive health status (MMSE score). The results showed that Prague citizens had consistently better performance in all verbal tests (for memory and verbal control, i.e., executive function) and attention than persons from other areas. The groups did not differ in timed visuo-graphomotor performance. The conclusion is that the complex environment of a city may promote, in the long-term, certain cognitive abilities, distinguishable even in a developed, culturally homogenous country. The implications are: (a) the description of samples used in normative studies should include information on the lived-in environment for the reference of researchers and clinicians; and (b) individual clinical assessment should reflect the role of the patient’s environment where appropriate. The exact mechanisms and causes of the differences need further investigation.

Electrophysiological repetition effects in persons with mild cognitive impairment depend upon working memory demand

Forms of implicit memory, including repetition effects, are preserved relative to explicit memory in clinical Alzheimer's disease. Consequently, cognitive interventions for persons with Alzheimer's disease have been developed that leverage this fact. However, despite the clinical robustness of behavioral repetition effects, altered neural mechanisms of repetition effects are studied as biomarkers of both clinical Alzheimer's disease and pre-morbid Alzheimer's changes in the brain. We hypothesized that the clinical preservation of behavioral repetition effects results in part from concurrent operation of discrete memory systems. We developed two experiments that included probes of emotional repetition effects differing in that one included an embedded working memory task. We found that neural repetition effects manifested in patients with amnestic mild cognitive impairment, the earliest form of clinical Alzheimer's disease, during emotional working memory tasks, but they did not manifest during the task that lacked the embedded working memory manipulation. Specifically, the working memory task evoked neural repetition effects in the P600 time-window, but the same neural mechanism was only minimally implicated in the task without a working memory component. We also found that group differences in behavioral repetition effects were smaller in the experiment with a working memory task. We suggest that cross-domain cognitive challenge can expose "defunct" neural capabilities of individuals with amnestic mild cognitive impairment.

Low Arousal Positive Emotional Stimuli Attenuate Aberrant Working Memory Processing in Persons with Mild Cognitive Impairment

Emotional enhancement effects on memory have been reported to mitigate the pathophysiology of Alzheimer's disease (AD). However, relative to their manifestation in persons without pathologic aging, these effects may be reduced in magnitude or even deleterious, especially in tasks that more closely model ecologic memory performance. Based upon a synthesis of such reports, we hypothesized that in persons with AD low arousal positive stimuli would evoke relatively intact emotional enhancement effects, but that high arousal negative stimuli would evoke disordered emotional enhancement effects. To assess this, participants with and without mild cognitive impairment (MCI) presumed to be due to AD performed an emotionally-valenced short-term memory task while encephalography was recorded. Results indicated that for persons with MCI, high arousal negative stimuli led to working memory processing patterns previously associated with MCI presumed due to AD and dementia of the Alzheimer-type. In contrast, low arousal positive stimuli evoked a processing pattern similar to MCI participants' unaffected spouses. Our current findings suggest that low arousal positive stimuli attenuate working memory deficits of MCI due to AD.

Spared behavioral repetition effects in Alzheimer's disease linked to an altered neural mechanism at posterior cortex

OBJECTIVE

Individuals with dementia of the Alzheimer type (AD) classically show disproportionate impairment in measures of working memory, but repetition learning effects are relatively preserved. As AD affects brain regions implicated in both working memory and repetition effects, the neural basis of this discrepancy is poorly understood. We hypothesized that the posterior repetition effect could account for this discrepancy due to the milder effects of AD at visual cortex.

METHOD

Participants with early AD, amnestic mild cognitive impairment (MCI), and healthy controls performed a working memory task with superimposed repetition effects while electroencephalography was collected to identify possible neural mechanisms of preserved repetition effects.

RESULTS

Participants with AD showed preserved behavioral repetition effects and a change in the posterior repetition effect.

CONCLUSION

Visual cortex may play a role in maintained repetition effects in persons with early AD.

Italians do it worse. Montreal Cognitive Assessment (MoCA) optimal cut-off scores for people with probable Alzheimer's disease and with probable cognitive impairment

Montreal cognitive assessment (MoCA) is a test providing a brief screening for people with cognitive impairment due to aging or neurodegenerative syndromes. In Italy, as in the rest of the world, several validation studies of MoCA have been carried out. This study compared, for the first time in Italy, a sample of people with probable Alzheimer's Disease (AD) with healthy counterparts. The study also compared two community-dwelling groups of aged participants with and without probable cognitive impairment, as discriminated by two cut-off points of adjusted MMSE score. All the comparisons were carried out according to ROC statistics. Optimal cutoff for a diagnosis of probable AD was a MoCA score ≤14. Optimal cutoff for the discrimination of probable cognitive impairment was a MoCA score ≤17 (associated to MMSE cutoff of 23.8). Results confirm the substantial discrepancy in cut-off points existing between Italian and other international validation studies, showing that Italian performance on MoCA seems to be globally lower than that in other Countries. Characteristics of population might explain these results.

Normative Study of the Functional Assessment of Verbal Reasoning and Executive Strategies (FAVRES) Test in the French-Canadian Population

PURPOSE

The Functional Assessment of Verbal Reasoning and Executive Strategies (FAVRES; MacDonald, 2005) test was designed for use by speech-language pathologists to assess verbal reasoning, complex comprehension, discourse, and executive skills during performance on a set of challenging and ecologically valid functional tasks. A recent French version of this test was translated from English; however, it had not undergone standardization. The development of normative data that are linguistically and culturally sensitive to the target population is of importance. The present study aimed to establish normative data for the French version of the FAVRES, a commonly used test with native French-speaking patients with traumatic brain injury in Québec, Canada.

METHOD

The normative sample consisted of 181 healthy French-speaking adults from various regions across the province of Québec. Age and years of education were factored into the normative model.

RESULTS

Results indicate that age was significantly associated with performance on time, accuracy, reasoning subskills, and rationale criteria, whereas the level of education was significantly associated with accuracy and rationale.

CONCLUSION

Overall, mean scores on each criterion were relatively lower than in the original English version, which reinforces the importance of using the present normative data when interpreting performance of French speakers who have sustained a traumatic brain injury.

Mild cognitive impairment (MCI) in long-term care patients: subtype classification and occurrence

OBJECTIVES

This study examines mild cognitive impairment (MCI) in long-term care settings by identifying and quantifying MCI subtypes in a combined sample of nursing home and assisted-living patients. We compared impairment thresholds of 1-SD and 1.5-SD to determine if different cut-offs differentially affect occurrence rates.

METHOD

One hundred and eight participants who met general criteria for MCI were included for the purposes of this study. The general diagnosis of MCI was based on criteria. Participants were further grouped into MCI subtypes. Based on previously established norms, Brief Cognitive Assessment Tool (BCAT) factor scores were used to assess whether MCI participants met either the 1-SD and 1.5-SD impairment thresholds for memory, executive functions, and attentional capacity.

RESULTS

Using both 1-SD and 1.5-SD impairment thresholds, three clear MCI subtypes were identified: amnestic, single-domain; non-amnestic, single-domain (executive); and amnestic, multi-domain (memory and executive). A fourth category (undifferentiated) was identified in patients who did not meet criteria for a distinct MCI subtype, but still had cognitive impairments. The stricter impairment threshold of 1.5-SD resulted in fewer patients classified as having any of the three domain-specific subtypes.

CONCLUSION

Based on a sample of nursing home and assisted-living patients, we identified three MCI subtypes, and a fourth category consisting of participants with general MCI, but without clear evidence of domain-specific cognitive impairment. When selecting impairment thresholds, one should consider the impact on the identification of MCI subtypes and the probability of misdiagnoses.

Normative Data for the Montreal Cognitive Assessment in Middle-Aged and Elderly Quebec-French People

OBJECTIVE

Given that aging is associated with higher risk of cognitive decline and dementia, improving early detection of cognitive impairment has become a research and clinical priority. The Montreal Cognitive Assessment (MoCA) is a screening instrument used to assess different aspects of cognition. Despite its widespread use, norms adjusted to the sociodemographics of Quebec-French people are not yet available. Such norms are however important because performance on neuropsychological tests varies according to sociodemographic variables including age, sex, and education. As such, the present study aimed to establish normative data for the MoCA in middle-aged and elderly Quebec-French population.

METHOD

For that purpose, 1,019 community-dwelling older adults aged between 41 and 98 were recruited. Participants from 12 recruiting sites completed the MoCA. Regression-based normative data were produced and cross-validated with a validation sample (n = 200).

RESULTS

Regression analyses indicated that older age, lower education level, and male sex were associated with poorer MoCA scores. The best predictive model included age (p < .001), education (p < .001), sex (p < .001), and a quadratic term for education (education X education; p < .001). This model explained a significant amount of variance of the MoCA score (p < .001, R2 = 0.26). A regression equation to calculate Z scores is presented.

CONCLUSIONS

This study provides normative data for the MoCA test in the middle-aged and elderly French-Quebec people. These data will facilitate more accurate detection and follow-up of the risk of cognitive impairment in this population, taking into account culture, age, education, and sex.

The Victoria Stroop Test: Normative Data in Quebec-French Adults and Elderly

OBJECTIVE

Despite the widespread use of the Victoria Stroop Test (VST; Regard, 1981) in clinical and research settings, information regarding the impact of sociodemographic variables on test performance in Quebec-French adults and elderly people is still nonexistent. Thus, this study aimed to establish normative data for error scores and completion time on all test trials (Dot, Word, and Interference) taking into account the impact of age, education, and sex on test performance.

METHOD

The sample consisted of 646 community-dwelling and healthy Quebec-French individuals aged between 47 and 87 years.

RESULTS

Regression analyses indicated that age was associated with completion time and error scores on all trials. The association was also positive for low and high interference conditions. Education was associated with completion time on Word and Interference trials, and with both interference scores. Finally, sex was associated with completion time on all trials, with women being consistently faster than men. Equations to calculate Z scores and percentiles are presented.

CONCLUSIONS

Norms for the VST will ease interpretation of executive functioning in Quebec-French adults and elderly and favor accurate discrimination between normal and pathological cognitive states.

Predicting Alzheimer's disease development: a comparison of cognitive criteria and associated neuroimaging biomarkers

Introduction

The definition of “objective cognitive impairment” in current criteria for mild cognitive impairment (MCI) varies considerably between research groups and clinics. This study aims to compare different methods of defining memory impairment to improve prediction models for the development of Alzheimer’s disease (AD) from baseline to 24 months.

Methods

The sensitivity and specificity of six methods of defining episodic memory impairment (< −1, −1.5 or −2 standard deviations [SD] on one or two memory tests) were compared in 494 non-demented seniors from the Alzheimer’s Disease Neuroimaging Initiative using the area under the curve (AUC) for receiver operating characteristic analysis. The added value of non-memory measures (language and executive function) and biomarkers (hippocampal and white-matter hyperintensity volume, brain parenchymal fraction [BPF], and APOEε4 status) was investigated using logistic regression.

Results

Baseline scores < −1 SD on two memory tests predicted AD with 75.91 % accuracy (AUC = 0.80). Only APOE ε4 status further improved prediction (B = 1.10, SE = 0.45, p = .016). A < −1.5 SD cut-off on one test had 66.60 % accuracy (AUC = 0.77). Prediction was further improved using Trails B/A ratio (B = 0.27, SE = 0.13, p = .033), BPF (B = −15.97, SE = 7.58, p = .035), and APOEε4 status (B = 1.08, SE = 0.45, p = .017). A cut-off of < −2 SD on one memory test (AUC = 0.77, SE = 0.03, 95 % CI 0.72-0.82) had 76.52 % accuracy in predicting AD. Trails B/A ratio (B = 0.31, SE = 0.13, p = .017) and APOE ε4 status (B = 1.07, SE = 0.46, p = .019) improved predictive accuracy.

Conclusions

Episodic memory impairment in MCI should be defined as scores < −1 SD below normative references on at least two measures. Clinicians or researchers who administer a single test should opt for a more stringent cut-off and collect and analyze whole-brain volume. When feasible, ascertaining APOE ε4 status can further improve prediction.

Normative data for a computer-assisted version of the auditory three-consonant Brown-Peterson paradigm in the elderly French-Quebec population

The Brown-Peterson task is used to assess verbal short-term memory as well as divided attention. In its auditory three-consonant version, trigrams are presented to participants who must recall the items in correct order after variable delays, during which an interference task is performed. The present study aimed to establish normative data for this test in the elderly French-Quebec population based on cross-sectional data from a retrospective, multi-center convenience sample. A total of 595 elderly native French-speakers from the province of Quebec performed the Memoria version of the auditory three-consonant Brown-Peterson test. For both series and item-by-item scoring methods, age, education, and, in most cases, recall after a 0-second interval were found to be significantly associated with recall performance after 10-second, 20-second, and 30-second interference intervals. Based on regression model results, equations to calculate Z scores are presented for the 10-second, 20-second and 30-second intervals and for each scoring method to allow estimation of expected performance based on participants' individual characteristics. As an important ceiling effect was observed at the 0-second interval, norms for this interference interval are presented in percentiles.

A Validation Study of Memory and Executive Functions Indexes in French-Speaking Healthy Young and Older Adults

Des scores composites mesurant les fonctions temporales médianes (FTM)/la mémoire et les fonctions frontales (FF)/exécutives sont utilisés pour indexer les changements cognitifs reliés au vieillissement. L’utilisation de ces scores en recherche gagne en popularité, mais s’appuie essentiellement sur les résultats de tests neuropsychologiques auprès des populations anglophones. Cette étude visait à valider les scores composites des FTM/la mémoire et FF/exécutives auprès d’adultes francophones. Quatre-vingt-dix-huit participants sains (32 jeunes et 66 âgés) ont été évalués à l’aide de trois tests neuropsychologiques associés aux FTM et cinq tests associés aux FF. Une analyse factorielle effectuée sur les scores résiduels indépendants de l’âge indique que les tests associés aux FTM et ceux associés aux FF se regroupent en deux facteurs distincts. Une analyse de type « bootstrapping » impliquant 1 000 rééchantillons indique que sept tests sont stables. Cette étude valide pour la première fois en français, des scores composites mesurant les FTM et FF.

Repeated retrieval during working memory is sensitive to amnestic mild cognitive impairment

Study of repeated learning mechanisms has been limited in amnestic mild cognitive impairment, a preclinical stage of Alzheimer disease modifiable by cognitive rehabilitation. We assessed repeated contextual working memory decline as an indicator of amnestic mild cognitive impairment in a sample of 45 older adults recruited from the tertiary care setting. Results indicated that contextual working memory impairment distinguished adults with preclinical disease from those without impairment despite similar overall cognitive performance, and comparison of the indicator with standard-of-care neuropsychological measures indicated discriminant validity. Contextual working memory impairment may represent a novel predictor of Alzheimer disease conversion risk.

Normative data for the Dementia Rating Scale-2 in the French-Quebec population

The Dementia Rating Scale-2 is used to measure cognitive status of adults with cognitive impairment, especially of the degenerative type, by assessing five cognitive functions, namely attention, initiation/perseveration, construction, conceptualization, and memory. The present study aimed to establish normative data for this test in the elderly French-Quebec population. A total of 432 French-speaking elders from the province of Quebec (Canada), aged 50 to 85 years, were administered the Dementia Rating Scale-2. Age and education were found to be associated with the total score on the test, while gender was not. Percentile ranks were then calculated for age- and education-stratified groups. Previous studies have shown that cultural background can affect performance on the DRS and the development of culture-specific norms for French-speaking Quebecers could be very useful to clinicians and researchers working with this population.

Lack of Correlation of WAIS Digit Span with Clox 1 and the Dementia Rating Scale in MCI

Individuals with MCI declined in performance over 6 months in the Clock-drawing (Clox 1) and the WAIS Digit Span tests, but not in the Dementia Rating Scale (DRS). Individual performance on Clox 1 and Digit Span did not correlate after 6 months. Performance on the Digit Span Test also did not correlate with the DRS, but performance on Clox 1 correlated with the DRS. Performance in Clox 1 was, therefore, not a predictor of performance in the Digit Span Test. These findings support the use of a test battery containing the Digit Span test to detect and track cognitive decline in MCI.

Using the Guttman scale to define and estimate measurement error in items over time: the case of cognitive decline and the meaning of "points lost"

We used a Guttman model to represent responses to test items over time as an approximation of what is often referred to as "points lost" in studies of cognitive decline or interventions. To capture this meaning of "point loss", over four successive assessments, we assumed that once an item is incorrect, it cannot be correct at a later visit. If the loss of a point represents actual decline, then failure of an item to fit the Guttman model over time can be considered measurement error. This representation and definition of measurement error also permits testing the hypotheses that measurement error is constant for items in a test, and that error is independent of "true score", which are two key consequences of the definition of "measurement error"--and thereby, reliability--under Classical Test Theory. We tested the hypotheses by fitting our model to, and comparing our results from, four consecutive annual evaluations in three groups of elderly persons: a) cognitively normal (NC, N = 149); b) diagnosed with possible or probable AD (N = 78); and c) cognitively normal initially and a later diagnosis of AD (converters, N = 133). Of 16 items that converged, error-free measurement of "cognitive loss" was observed for 10 items in NC, eight in converters, and two in AD. We found that measurement error, as we defined it, was inconsistent over time and across cognitive functioning levels, violating the theory underlying reliability and other psychometric characteristics, and key regression assumptions.