An Arabic Version of the Cognitive Subscale of the Alzheimer's Disease Assessment Scale (ADAS-Cog): Reliability, Validity, and Normative Data

Phenotypic Spectrum of Progressive Supranuclear Palsy: Clinical Study and Apolipoprotein E Effect

OBJECTIVE

Progressive supranuclear palsy (PSP) is a rare neurodegenerative disorder encompassing several phenotypes with various motor and cognitive deficits. We aimed to study motor and cognitive characteristics across PSP phenotypes and to assess the influence of apolipoprotein E (APOE) gene variants on PSP phenotypic expression.

METHODS

In this 20-year cross-sectional study, we retrospectively reviewed the charts of all patients classified as PSP patients and recategorized them according to phenotype using the Movement Disorder Society criteria (2017). Phenotypes were divided into three subgroups, Richardson's syndrome (PSP-RS), PSP-cortical (PSP with predominant frontal presentation [PSP-F] + PSP with predominant speech/language disorder [PSP-SL] + PSP with predominant corticobasal syndrome [PSP-CBS]) and PSP-subcortical (PSP with predominant parkinsonism [PSP-P] + PSP with progressive gait freezing [PSP-PGF] + PSP with predominant postural instability [PSP-PI] + PSP with predominant ocular motor dysfunction [PSP-OM] + PSP with cerebellar ataxia [PSP-C] + PSP with primary lateral sclerosis [PSP-PLS]), based on clinical presentation during the first 3 years after symptom onset, which defines the early disease stage. Clinical and neuropsychological assessment data were collected. Genotyping of APOE was performed using restriction fragment length polymorphism polymerase chain reaction and verified by Sanger sequencing.

RESULTS

We included 112 PSP patients comprising 10 phenotypes classified into 48 PSP-RS, 34 PSP-cortical (PSP-CBS, 17.6%; PSP-F, 9.4%; PSP-SL, 8.2%) and 30 PSP-subcortical (PSP-P, 11.6%; PSP-PI, 8%; PSP-OM, 2.7%; PSP-PGF, 1.8%; PSP-C, 1.8%; PSP-PLS, 0.9%) subgroups. PSP-RS patients were older at disease onset (p = 0.009) and had more akinetic-rigid and levodopa-resistant parkinsonism (p = 0.006), while PSP-cortical patients had more tremors and asymmetric and/or levodopa-responsive parkinsonism (p = 0.025). Cognitive domains were significantly less altered in the PSP-subcortical subgroup. Overall, PSP-APOEε4 carriers developed parkinsonism earlier (p = 0.038), had earlier oculomotor dysfunction (p = 0.052) and had more altered cognitive profiles. The APOEε4 allele was also associated with a younger age of parkinsonism onset in the PSP-RS phenotype group (p = 0.026).

CONCLUSION

This study demonstrated the wide phenotypic spectrum of PSP among Tunisians. Disease onset and akinetic-rigid and levodopa-resistant parkinsonism were the hallmarks of the PSP-RS phenotype, while milder cognitive impairment was characteristic of the PSP-subcortical subgroup. The APOEε4 allele was associated with earlier parkinsonism and oculomotor dysfunction and seemed to play a role in defining a more altered cognitive profile in PSP patients.

Optineurin in patients with Amyotrophic Lateral Sclerosis associated to atypical Parkinsonism in Tunisian population

Amyotrophic Lateral Sclerosis (ALS) is a heterogeneous disorder and the phenotypic variability goes far beyond the used clinical stratification parameter. Evidence has emerged that ALS may coexist with distinct neurodegenerative diseases in single cases. We aim to study the clinical features of two familial cases of ALS carriers of two distinct variants harbored in the Optineurin (OPTN) gene. We included definite familial ALS followed up in the Department of Neurology of Razi University Hospital, Tunisia, and selected according to Byrne criteria. Preliminary screening for the four main ALS genes (SOD1, C9ORF72, TARDBP, FUS) was conducted. Given the negative results, we proceeded to NGS target-re-sequencing with a custom panel including genes associated with ALS-FTD, Alzheimer's, and Parkinson's diseases. Both families are carriers of two different OPTN variants and they present very different ALS clinical features. The first family comprises two siblings diagnosed with ALS and Corticobasal syndrome (ALS-CBS) at an early age of onset and carriers of OPTN p.E135X in the homozygous state. The proband for the second family was diagnosed with ALS at an early age of onset presenting as progressive muscular atrophy with rapid progression. Genetic analysis revealed the presence of the homozygous variant p.R520H. Our findings highlight the peculiarity of genetic Tunisian drift. Indeed, genes with a recessive mode of inheritance may explain part of ALS diversity in clinical features. Therefore, the screening of the OPTN gene is highly recommended among inbreeding populations such as the Tunisian one.

Bayesian estimation for the accuracy of three neuropsychological tests in detecting Alzheimer's disease and mild cognitive impairment: a retrospective analysis of the ADNI database

BACKGROUND

The neuropathological confirmation serves as the gold standard for diagnosing Alzheimer's disease (AD), but it is usually not available to the living individuals. In addition, the gold standard for diagnosing Mild Cognitive Impairment (MCI) remains unclear yet. Neuropsychological testing, such as the Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE) and Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog), is commonly used tests in identifying AD and MCI, offering convenience, affordability, non-invasiveness, and accessibility in clinical settings. We aimed to accurately evaluate the discriminative ability of the three tests administrated at the same visit simultaneously in detecting AD and MCI due to AD in the absence of a gold standard.

METHODS

A total of 1289 participants aged over 65 were included from the baseline visits of Alzheimer's disease Neuroimaging Initiative. Bayesian latent class models, accounting for conditional dependence between MoCA and MMSE, were conducted to assess the diagnostic accuracy of the three tests for detecting AD and MCI.

RESULTS

In detecting AD, the ADAS-cog had the highest Youden's Index (0.829), followed by the MoCA(0.813) and MMSE(0.796). The ADAS-cog and MoCA showed similar sensitivity (0.922 vs 0.912) and specificity (0.907 vs 0.901), while the MMSE had lower sensitivity (0.874) and higher specificity (0.922). For MCI detection, the ADAS-cog had the highest Youden's Index (0.704) compared to the MoCA (0.614) and MMSE (0.478). The ADAS-cog exhibited the highest sensitivity, closely followed by the MoCA and MMSE (0.869 vs 0.845 vs 0.757), and the ADAS-cog also had good specificity (0.835 vs 0.769 vs 0.721). The estimated true prevalence of AD among individuals aged over 65 was 20.0%, and the estimated true prevalence of MCI due to AD was 24.8%.

CONCLUSIONS

The findings suggest that the ADAS-cog and MoCA are reliable tools for detecting AD and MCI, while the MMSE may be less sensitive in detecting these conditions. A large underdiagnosis of the MCI and Alzheimer's population still remains in clinical screening.

Predicting mild cognitive impairment progression to Alzheimer's disease based on machine learning analysis of cortical morphological features

PURPOSE

To establish a model for predicting mild cognitive impairment (MCI) progression to Alzheimer's disease (AD) using morphological features extracted from a joint analysis of voxel-based morphometry (VBM) and surface-based morphometry (SBM).

METHODS

We analyzed data from 121 MCI patients from the Alzheimer's Disease Neuroimaging Initiative, 32 of whom progressed to AD during a 4-year follow-up period and were classified as the progression group, while the remaining 89 were classified as the non-progression group. Patients were divided into a training set (n = 84) and a testing set (n = 37). Morphological features measured by VBM and SBM were extracted from the cortex of the training set and dimensionally reduced to construct morphological biomarkers using machine learning methods, which were combined with clinical data to build a multimodal combinatorial model. The model's performance was evaluated using receiver operating characteristic curves on the testing set.

RESULTS

The Alzheimer's Disease Assessment Scale (ADAS) score, apolipoprotein E (APOE4), and morphological biomarkers were independent predictors of MCI progression to AD. The combinatorial model based on the independent predictors had an area under the curve (AUC) of 0.866 in the training set and 0.828 in the testing set, with sensitivities of 0.773 and 0.900 and specificities of 0.903 and 0.747, respectively. The number of MCI patients classified as high-risk for progression to AD was significantly different from those classified as low-risk in the training set, testing set, and entire dataset, according to the combinatorial model (P < 0.05).

CONCLUSION

The combinatorial model based on cortical morphological features can identify high-risk MCI patients likely to progress to AD, potentially providing an effective tool for clinical screening.

Eye movement study in essential tremor patients and its clinical correlates

Essential tremor (ET) encompasses a wide spectrum of motor and non-motor features. Eye movement abnormalities were first reported two decades ago as an atypical finding in ET. Today, a growing number of publications about eye movement abnormalities in neurodegenerative diseases have helped understand their pathophysiology and the basis of their phenotypic variability. Thus, addressing such aspect in ET may disentangle, based on the oculomotor network abnormalities, the dysfunctional brain pathways in ET. In this study, we aimed to describe neurophysiological eye movement abnormalities in ET and their clinical correlates in terms of cognition and other associated clinical signs. We conducted a cross-sectional study in a tertiary neurology referral center including consecutive ET patients and cognitively normal healthy controls (HC) matched for age and sex. The study protocol included the assessment of voluntary horizontal saccades, smooth pursuit, anti-saccades and saccadic intrusions. We assessed the associated motor signs, cognitive functions and the presence of rapid eye movement disorder (RBD). Sixty-two ET patients and 66 HC were enrolled in the study. Eye movement examination showed significant abnormalities in comparison with HC (46.7% vs 20%, p = 0.002). Prolonged saccadic latency (38.7%, p = 0.033) and altered smooth pursuit (38.7%, p = 0.033) were the most common abnormalities in ET patients. Anti-saccadic errors (16% vs 0% in HC, p = 0.034) correlated with the presence of rigidity (p = 0.046), bradykinesia (p = 0.001), cognitive dysfunction (p = 0.006), executive dysfunction (p = 0.0002), apraxia (p = 0.0001), altered verbal fluency (p = 0.013) and altered backward digit span (p = 0.045) along with the presence of RBD (p = 0.035). Square-wave jerks (11.5% vs 0% in HC, p = 0.0024) correlated with rest tremor. A distinctive phenotype of ET could emerge out of this study characterized by anti-saccadic errors and a sub-cortical cognitive profile, consecutive to the disruption of the cerebello-thalamo-cortical loop. Patients with anti-saccadic errors could be cognitively vulnerable and in need of a close monitoring of their cognitive efficiency during the disease's progression. They may as well convert to Parkinson disease if they present with parkinsonism, RBD and square-wave jerks and require, consequently, a close observation of their motor progression.

Determinants of cognitive impairment in multiple system atrophy: Clinical and genetic study

INTRODUCTION

Classically, cognitive impairment (CI) was not considered as a paramount feature of multiple system atrophy(MSA) in both parkinsonian(MSA-P) and cerebellar(MSA-C) motor-subtypes. Yet, growing evidence indicates currently the commonness of such deficits among MSA patients in different populations. Our aim was to evaluate the cognitive profile of MSA Tunisian patients and to analyze the underlying clinical and genetic determinants.

METHODS

In a retrospective cross-sectional study, clinically-diagnosed MSA patients were included. All subjects underwent clinical and neuropsychological assessments to characterize their cognitive profile. The associations with their APOE genotype status were analyzed. Determinant of CI were specified.

RESULTS

We included 71 MSA patients. Female gender(sex-ratio = 0.65) and MSA-P subtype(73%) were predominant. Mean age of disease onset was 59.1years. CI was found in 85.7% of patients(dementia in 12.7% and Mild cognitive impairment(MCI) in 73% of patients mainly of multiple-domain amnestic type(37.3%)). Mean MMSE score was lower among MSA-P compared to MSA-C(23.52 vs. 26.47;p = 0.027). Higher postural instability gait disorder(PIGD) and MDS-UPDRS-III scores were noted in demented MSA patients(p = 0.019;p = 0.015 respectively). The main altered cognitive domain was attention(64.8%). Executive functions and mood disorders were more affected in MSA-P(p = 0.029,p = 0.035 respectively). Clinical and neurophysiological study of dysautonomia revealed no differences across cognitive subtypes. APOE genotyping was performed in 51 MSA patients with available blood samples. Those carrying APOEε4 had 1.32 fold higher risk to develop CI, with lower MMSE score(p = 0.0001). Attention and language were significantly altered by adjusting the p value to APOEɛ4 carriers(p = 0.046 and p = 0.044 respectively). Executive dysfunction was more pronounced among MSA-PAPOEε4 carriers(p = 0.010).

CONCLUSION

In this study, the main determinants of CI in Tunisian MSA patients were MSA-P motor-subtype, mainly of PIGD-phenotype, disease duration and APOEε4 carrying status, defining a more altered cognitive phenotype. This effect mainly concerned executive, attention and language functions, all found to be more impaired in APOEε4 carriers with variable degrees across MSA motor-subtypes.

Validation of Slovenian version of ADAS-Cog for patients with mild cognitive impairment and Alzheimer's disease

INTRODUCTION

Alzheimer's disease (AD) is the most common cause of neurodegenerative dementia where the most prominent cognitive impairment is memory loss. Screening tests are valuable tools for detecting cognitive impairment. One such test is the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) which consists of 11 tasks. The main goal of our study was to validate the Slovenian version of the ADAS-Cog for detecting mild cognitive impairment (MCI) and AD patients.

METHODS

Our sample included 128 participants: 61 healthy controls, 32 people with MCI, and 35 with AD. All participants were evaluated with the Slovenian translation of ADAS-Cog.

RESULTS

The optimal cut-off for the ADAS-Cog for MCI was 10/11 points. The sensitivity was 88%, specificity 85% and likelihood ratio 6. The optimal cut-off for AD was 11/12 points. Sensitivity was 100%, specificity 95% and likelihood ratio 20.

CONCLUSION

The obtained cut-off values are comparable to the results from similar validation studies. We can conclude that the ADAS-Cog is a reliable and valid tool for identifying people with MCI and AD from among healthy controls in the Slovenian population.

Cultural adaptation of Alzheimer's disease assessment scale-cognitive subscale for use in India and validation of the Tamil version for South Indian population

OBJECTIVE

Currently no standardized tools are available in the Indian languages to assess changes in cognition. Our objectives are to culturally adapt the Alzheimer's disease Assessment Scale-Cognitive Subscale (ADAS-Cog) for use in India and to validate the Tamil version in an urban Tamil-speaking older adult population.

METHODS

Two panels of key stakeholders and a series of qualitative interviews informed the cultural and linguistic adaptation of the ADAS-Cog-Tamil. Issues related to levels of literacy were considered during the adaptation. Validation of the ADAS-Cog-Tamil was completed with 107 participants - 54 cases with a confirmed diagnosis of mild-moderate dementia, and 53 age, gender and education matched controls. Concurrent validity was examined with the Vellore Screening Instrument for Dementia (VSID) in Tamil. Internal consistency using Cronbach's alpha, sensitivity and specificity data using the Area under the Receiver Operating Characteristics (AUROC) curve values were computed. Inter-rater reliability was established in a subsample.

RESULTS

The ADAS-Cog-Tamil shows good internal consistency (α = 0.91), inter-rater reliability and concurrent validity (with VSID-Patient version: r = -0.84 and with VSID-Caregiver version: r = -0.79). A cut-off score of 13, has a specificity of 89% and sensitivity of 90% for the diagnosis of dementia.

CONCLUSION

ADAS-Cog-Tamil, derived from a rigorous, replicable linguistic and cultural adaptation process involving service users and experts, shows good psychometric properties despite the limitations of the study. It shows potential for use in clinical settings with urban Tamil speaking populations. The English version of the tool derived from the cultural adaptation process could be used for further linguistic adaptation across South Asia.

Role of Apolipoprotein E in the Clinical Profile of Atypical Parkinsonian Syndromes

INTRODUCTION

Atypical Parkinsonian syndromes (APS) encompass a spectrum of neurodegenerative diseases including dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP), multiple system atrophy (MSA), and corticobasal syndrome (CBS). The effects of the Apolipoprotein E (APOE) gene on APS clinical features are controversial and understudied in several populations. We aimed to explore the influence of APOE genotype on clinical features in an APS Tunisian cohort.

METHODS

We included clinically diagnosed APS patients genotyped for APOE, and analyzed the clinical and APOE genotype associations.

RESULTS

A total of 328 APS patients were included, comprising 184 DLB, 58 PSP, 49 MSA, and 37 CBS. Significant differences in initial Mini-Mental State Examination and Frontal Assessment Battery scores according to APOE genotypes (P=0.05 and 0.0048) were found. Executive dysfunction (P=0.026) disorientation (P=0.025), and hallucinations (P<0.001) were more pronounced among APOE-ɛ4 carriers particularly in DLB. Memory disorders were also correlated to APOE-ɛ4 allele (P=0.048) and were more frequent among DLB and PSP carriers. Depression was associated to APOE-ε4 (P=0.042), more markedly in APOE-ε4-CBS and MSA carriers.

CONCLUSIONS

Our findings suggested a role of APOE-ε4 in defining a more altered cognitive phenotype with variable degrees across subgroups in APS patients, especially in DLB carriers. This effect mainly concerned executive, memory and orientation functions as well as hallucinations.

Clinical and Objective Cognitive Measures for the Diagnosis of Cognitive Frailty Subtypes: A Comparative Study

Background

Cognitive frailty (CF) includes reversible and potentially reversible subtypes; the former is known as concurrent physical frailty (PF) and pre-mild cognitive impairment subjective cognitive decline (pre-MCI SCD), whereas the latter is known as concurrent PF and MCI. The diagnoses of pre-MCI SCD and MCI are based on clinical criteria and various subjective cognitive decline questionnaires. Heterogeneous assessment of cognitive impairment (CI) results in significant variability of CI, CF, and their subtype prevalence in various population-based studies.

Objective

This study aimed to compare the classification differences in CI and CF subtypes from PF and normal cognition by applying clinical and objective cognitive criteria. Clinical criteria comprised Fried PF and clinical MCI criteria combined with the SCD questionnaire, whereas objective criteria comprised Fried PF and objective cognitive criteria based on the norm-adjusted six neuropsychological test scores.

Methods

Of the 335 volunteers (age ≥ 60 years) in this study, 191 were diagnosed with CI based on clinical cognitive diagnosis criteria, and 144 were identified as robust normal based on objective cognitive assessment from the community-dwelling older adult cohort. Individuals with clinical CI, including 94 with MCI and 97 with pre-MCI SCD, were reclassified into different z-score-derived MCI, pre-MCI SCD, and normal subgroups based on objective cognitive criteria. The classification diagnostic accuracy of normal cognition, PF, pre-MCI, MCI, CF, and CF subtypes based on clinical and objective criteria was compared before and after adjusting for age, sex, and education level.

Results

The reclassification of objective assessments indicated better performance than that of clinical assessments in terms of discerning CI severity among different subgroups before adjusting for demographic factors. After covariate adjustment, clinical assessments significantly improved the ability to cognitively discriminate normal individuals from those with pre-MCI SCD and MCI but not the z-score-derived pre-MCI SCD and MCI groups from the robust normal group. Furthermore, the adjustment did not improve the ability to discriminate among individuals with reversible CF from those with potentially reversible CF and pre-MCI only SCD from MCI only SCD.

Conclusions

Objective criteria showed better performance than clinical criteria in the diagnosis of individuals with CI or CF subtypes. Rapid clinical cognitive screening in combination with normative z-scores criteria is cost effective and sustainable in clinical practice.

Construction and Standardization of Dementia Arabic Scale

PURPOSE

Validated diagnostic scales for dementia in Arabic are still scarce. The aim of this study is to construct a standardized dementia scale for dementia diagnosis among the Arabic-speaking population.

PATIENTS AND METHODS

Construction of the Dementia Arabic Scale (DAS) was done, followed by evaluation of content validity. A pilot study was done to ascertain feasibility and language clarity used in the scale. Patients diagnosed to have major neurocognitive disorder according to DSM-V criteria and control group were subjected to DAS, mini-mental state examination (MMSE) and Cognitive Abilities Screening Instrument (CASI). Finally, standardization of the scale and estimation of cutoff point, sensitivity, specificity, positive predictive value and negative predictive value of the newly constructed scale (DAS) were done.

RESULTS

There is significant correlation between DAS and both MMSE and CASI on Pearson's correlation study. The internal consistency of the DAS scale was good, with Cronbach's alpha correlation coefficient of 0.88. At cut-off ≤95 for literate, and ≤68 for illiterate, the sensitivity of the DAS scale was 100%, 87% for literate and illiterate, respectively, while specificity was 84%, 96% respectively, with an area under the receiver operating characteristic curve of (AUC) 0.96.

CONCLUSION

The DAS scale is an acceptable, reliable and valid scale for the diagnosis of dementia in Arabic-speaking countries.

Reliability and concurrent validity of Alzheimer's disease assessment scale - Cognitive subscale, Chinese version (ADAS-Cog-C) among Chinese community-dwelling older people population

OBJECTIVE

To evaluate reliability and concurrent validity of the Alzheimer's Disease Assessment Scale - Cognitive Subscale, Chinese Version (ADAS-Cog-C) among Chinese community older adults.

METHOD

Three groups, comprising of 1,276 community-dwelling older adults, were included in this study: a normal control (NC), a mild cognitive impairment (MCI), and an Alzheimer's disease (AD) group. All participants were assessed through ADAS-Cog-C, clinical interviews, physical examinations, Mini Mental State Examination (MMSE), and the Clinical Dementia Rating Scale (CDR). Internal consistency was assessed to evaluate the reliability of ADAS-Cog-C. Pearson and Spearman correlation coefficients were calculated to evaluate the concurrent validity between ADAS-Cog-C, MMSE, and CDR.

RESULTS

Overall, the Cronbach's alpha coefficients of ADAS-Cog-C for the AD and MCI groups were 0.843 and 0.554, respectively. The split-half reliability coefficients for the AD and MCI groups were 0.860 and 0.539, respectively. ADAS-Cog-C scores were negatively correlated with MMSE scores (r = -0.706, p < 0.001) and positively associated with CDR scores (r = 0.546, p < 0.001). After excluding the MCI group from the analysis, the internal consistency of ADAS-Cog-C for the total population improved (α = 0.813, r _hh = 0.852, all p < 0.001), as did the correlation between ADAS-Cog-C and MMSE (r = -0.828, p < 0.001) and CDR (r = 0.429, all p < 0.001) scores.

CONCLUSIONS

ADAS-Cog-C has good internal consistency and concurrent validity for assessing Chinese community older adults with AD, but poor consistency, good concurrent validity with the MMSE while moderate concurrent validity with the CDR for MCI.

Eye tracking metrics to screen and assess cognitive impairment in patients with neurological disorders

PURPOSE OF REVIEW

Eye tracking is a powerful method to investigate the relationship between behavior and neural mechanisms. In recent years, eye movement analysis has been used in patients with neurological disorders to assess cognitive function. In this review, we explore the latest eye tracking researches in neurological disorders that are commonly associated with cognitive deficits, specifically, amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), and epilepsy. We focus on the application of ocular measures in these disorders, with the goal of understanding how eye tracking technology can be used in the clinical setting.

FINDINGS

Eye tracking tasks (especially saccadic tasks) are often used as an adjunct to traditional scales for cognitive assessment. Eye tracking data confirmed that executive dysfunction is common in PD and ALS, whereas AD and MS are characterized by attention deficits. Research in evaluating cognitive function in epilepsy using eye tracking is still in its early stages, but this approach has shown advantages as a sensitive quantitative method with high temporal and spatial resolution. Eye tracking technology can facilitate the assessment of cognitive impairment with higher temporal resolution and finer granularity than traditional cognitive assessment. Oculomotor data collected during cognitive tasks can provide insight into biological processes. Eye tracking provides a nonverbal and less cognitively demanding method of measuring disease progression in cognitively impaired patients.

Validation study of the Alzheimer's Disease Assessment Scale-Cognitive Subscale for people with mild cognitive impairment and Alzheimer's disease in Chinese communities

OBJECTIVE

Our study aimed to verify the validity of the Chinese version of Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) for the community-dwelling older people in China.

METHODS

A total of 1276 individuals composed by 628 normal controls (NCs), 572 people living with mild cognitive impairment (MCI), and 76 people living with Alzheimer's disease (AD) were recruited for the current study. All of the participants underwent ADAS-Cog, clinical interview and examination, Quick Cognitive Screening Scale for the Elderly, and Activities of Daily Living Scale. The sensitivity and specificity of ADAS-Cog were calculated, and a receiver operating characteristic curve (ROC curve) was drawn to decide the optimal cutoff points of ADAS-Cog for screening MCI and AD.

RESULTS

Statistically significant differences were observed among the three groups (P <. 001, NC < MCI <AD), in terms of the total and subtask scores of ADAS-Cog. The optimal cutoff value for MCI was 10 points with an area under the curve (AUC) of 0.824, sensitivity of 61.4%, and specificity of 93.2%. Comparatively, the best cutoff value for AD was 15 points with an AUC of 0.905, sensitivity of 73.7%, and specificity of 92.4%. The overall accuracy was 70.5%, and the accuracy of diagnosing cognitively healthy older people, MCI patients, and AD patients was 81.7%, 58.0%, and 71.1%, respectively.

CONCLUSION

The present study illustrates that the Chinese version of the ADAS-Cog total score is able to detect cognitive impairment of AD patients in Chinese communities but has a lower efficacy for MCI.

Arab American Cognitive Aging: Opportunities for Advancing Research on Alzheimer's Disease Disparities

Background and Objectives

This article highlights the dearth of and need for research on Arab American cognitive aging. We propose that studying cognitive health issues among older Arab Americans provides an innovative opportunity to advance knowledge about causes and consequences of Alzheimer’s disease (AD) disparities and refine understanding of factors linked to immigrant health in the United States.

Research Design and Methods

Demographic information is provided on Arab Americans, who are on the cusp of being recognized by the U.S. government as a distinct ethnic group separate from whites. In the tradition of minority aging, we present a broad review of specific issues in the contemporary case of Arab Americans.

Results

We detail how including Arab Americans provides unique information on the importance of: (i) extending racial/ethnic group comparisons; (ii) linking social experiences to late-life cognitive health; and (iii) incorporating ethnic factors related to immigration and religion in the study of AD disparities.

Discussion and Implications

Studying Arab American cognitive aging provides an innovative opportunity to more fully delineate factors that create and sustain health disparities, with special insights into both causes and consequences.