The Dementia and Disability Project in Thai Elderly: rational, design, methodology and early results

The age differences and effect of mild cognitive impairment on perceptual-motor and executive functions

It is unclear whether the decline in executive function (EF) and perceptual-motor function (PMF) found in older adults with mild cognitive impairment (MCI) is the result of a normal aging process or due to MCI. This study aimed to determine age-related and MCI-related cognitive impairments of the EF and PMF. The EF and PMF were investigated across four groups of 240 participants, 60 in each group, including early adult, middle adult, older adult, and older adult with probable MCI. The EF, working memory, inhibition, and cognitive flexibility were evaluated using digit span backward tasks, the Stroop color-word test, and the modified switching verbal fluency test, respectively. The PMF, visual perception, visuoconstructional reasoning, and perceptual-motor coordination were evaluated using the clock reading test, stick design test, and stick catching test, respectively. Group differences were found for all subdomains of EF and PMF (p < 0.05), except for perceptual-motor coordination, indicating that this subdomain could be maintained in older adults and was not affected by MCI. For the age difference, working memory, cognitive flexibility, visual perception, and visuoconstructional reasoning remained stable across middle adults and started to decline in older adults, while cognitive inhibition began to decrease in middle adults and it further declined in older adults. To control the confounding effect of education level, the results showed that only cognitive flexibility was further decreased in older adults with probable MCI compared to those without MCI (p < 0.05). In conclusion, cognitive inhibition decreased earlier in middle adults, whereas EF and PMF started to decline in older adults. Cognitive flexibility was the only MCI-sensitive cognitive function.

Systematic review estimating the burden of dementia in the WHO Southeast Asia Region using Bayesian and frequentist approaches

Background

Rapid increase in life expectancy in low- and middle-income countries including the World Health Organization’s Southeast Asia Region (SEAR) has resulted in an increase in the global burden of dementia, which is expected to become a leading cause of morbidity. Accurate burden estimates are key for informing policy and planning. Given the paucity of data, estimates were developed using both a Bayesian methodology and as well as a traditional frequentist approach to gain better insights into methodological approaches for disease burden estimates.

Methods

Seven databases were searched for studies published between 2010-2018 regarding dementia prevalence in SEAR, generating 8 relevant articles. A random-effects model (REM) and a Bayesian normal-normal hierarchical model (NNHM) were used to obtain the pooled prevalence estimate of dementia for people aged 60 and above in SEAR. The latter model was also developed to estimate age-specific dementia prevalence. Using UN population estimates for SEAR, total and age-specific projections of the burden of dementia in 2015, 2020 and 2030 were calculated.

Results

The prevalence of dementia in SEAR was found to be 3% (95% confidence interval (CI) = 2-6%) in those above age 60 based on REM, and 3.1% (95% credible interval = 1.5-5.0%) based on the NNHM. The estimated prevalence varies with age, increasing from 1.6% (95% credible interval = 0.8-2.5%) in people aged 60-69 to 12.4% (95% credible interval = 5.6-20%) in people above the age of 80. The risk of developing dementia increased exponentially with age. The number of people living with dementia in SEAR in 2015 was estimated at 5.51 million (95% credible interval = 2.66-8.82), with projections of 6.66 million (95% credible interval = 3.21-10.7) in 2020 and 9.6 million (95% credible interval = 4.62-15.36) in 2030.

Conclusion

The burden of dementia in SEAR is substantial and will continue to increase rapidly by 2030. The lack of research focusing on dementia in SEAR points to a significant under-recognition of this disease. The projected rise in dementia cases in the future should prompt urgent governmental response to address this growing public health issue. We also argue that given the overall paucity of data for the region, the Bayesian approach offers a promising methodology for improved estimates of disease prevalence and burden and should continue to be explored.

Etiology of Dementia in Thai Patients

Introduction

Molecular imaging has been developed and validated in Thai patients, comprising a portion of patients in the dementia registry. This should provide a more accurate diagnosis of the etiology of dementia, which was the focus of this study.

Methods

This was a multicenter dementia study. The baseline characteristics, main presenting symptoms, and results of investigations and cognitive tests of the patients were electronically collected in the registry. Functional imaging and/or molecular imaging were performed in patients with an equivocal diagnosis of the causes of dementia, especially in atypical dementia or young onset dementia (YOD).

Results

There were 454 patients in the study. The mean age of the patients was 78 years, with 60% female. Functional imaging and/or molecular imaging were performed in 57 patients (57/454 patients, 13%). The most common cause of dementia was Alzheimer's disease (AD; 50%), followed by vascular dementia (VAD; 24%), dementia with Lewy bodies (6%), Parkinson's disease dementia (6%), frontotemporal dementia (FTD; 2.6%), progressive supranuclear palsy (2%), multiple system atrophy (0.8%), and corticobasal syndrome (0.4%). YOD accounted for 17% (77/454 patients), with a mean age of 58 years. The causes of YOD were early onset amnestic AD (44%), VAD (16%), behavioral variant FTD (8%), posterior cortical atrophy (6.5%), and logopenic variant primary progressive aphasia (5.2%).

Conclusion

AD was the most common cause of dementia in Thai patients and the distribution of other types of dementia and main presenting symptoms were similar to previous reports in Western patients; however, the proportion of YOD was higher.

Accuracy of Support-Vector Machines for Diagnosis of Alzheimer's Disease, Using Volume of Brain Obtained by Structural MRI at Siriraj Hospital

Background: The determination of brain volumes using visual ratings is associated with an inherently low accuracy for the diagnosis of Alzheimer's disease (AD). A support-vector machine (SVM) is one of the machine learning techniques, which may be utilized as a classifier for various classification problems. This study exploratorily investigated the accuracy of SVM classification models for AD subjects using brain volume and various clinical data as features.

Methods: The study was designed as a retrospective chart review. A total of 201 eligible subjects were recruited from the Memory Clinic at Siriraj Hospital, Thailand. Eighteen cases were excluded due to incomplete MRI data. Subjects were randomly assigned to a training group (AD = 46, normal = 46) and testing group (AD = 45, normal = 46) for SVM modeling and validation, respectively. The results in terms of accuracy and a receiver operating characteristic curve analysis are reported.

Results: The highest accuracy for brain volumetry (62.64%) was found using the hippocampus as a single feature. A combination of clinical parameters as features provided accuracy ranging between 83 and 90%. However, a combination of brain volumetry and clinical parameters as features to the SVM models did not improve the accuracy of the result.

Conclusions: In our study, the use of brain volumetry as SVM features provided low classification accuracy with the highest accuracy of 62.64% using the hippocampus volume alone. In contrast, the use of clinical parameters [Thai mental state examination score, controlled oral word association tests (animals; and letters K, S, and P), learning memory, clock-drawing test, and construction-praxis] as features for SVM models provided good accuracy between 83 and 90%.

Alterations in Mitochondrial Dynamic-related Genes in the Peripheral Blood of Alzheimer's Disease Patients

BACKGROUND

Mitochondrial dysfunction is a pathological feature that manifests early in the brains of patients with Alzheimer's Disease (AD). The disruption of mitochondrial dynamics contributes to mitochondrial morphological and functional impairments. Our previous study demonstrated that the expression of genes involved in amyloid beta generation was altered in the peripheral blood of AD patients.

OBJECTIVE

The aim of this study was to further investigate the relative levels of mitochondrial genes involved in mitochondrial dynamics, including mitochondrial fission and fusion, and mitophagy in peripheral blood samples from patients with AD compared to healthy controls.

METHODS

The mRNA levels were analyzed by real-time polymerase chain reaction. Gene expression profiles were assessed in relation to cognitive performance.

RESULTS

Significant changes were observed in the mRNA expression levels of fission-related genes; Fission1 (FIS1) levels in AD subjects were significantly higher than those in healthy controls, whereas Dynamin- related protein 1 (DRP1) expression was significantly lower in AD subjects. The levels of the mitophagy-related genes, PTEN-induced kinase 1 (PINK1) and microtubule-associated protein 1 light chain 3 (LC3), were significantly increased in AD subjects and elderly controls compared to healthy young controls. The mRNA levels of Parkin (PARK2) were significantly decreased in AD. Correlations were found between the expression levels of FIS1, DRP1 and PARK2 and cognitive performance scores.

CONCLUSION

Alterations in mitochondrial dynamics in the blood may reflect impairments in mitochondrial functions in the central and peripheral tissues of AD patients. Mitochondrial fission, together with mitophagy gene profiles, might be potential considerations for the future development of blood-based biomarkers for AD.

Relationships between amyloid levels, glucose metabolism, morphologic changes in the brain and clinical status of patients with Alzheimer's disease

OBJECTIVE

The current study was conducted to improve the understanding of relationships between regional cortical amyloid load, glucose metabolism, cortical morphology (volume), and severity of clinical symptoms in patients with AD, MCI, and age-matched controls.

METHODS

To objectivize the radiological evaluation of patients with suspected AD, head-to-head multi-modality imaging studies were conducted using MRI and PET/CT with [¹⁸F]FDG and [¹⁸F]AV45 for visualization and quantitation of brain morphology, glucose metabolism, and amyloid levels, respectively. A total of 84 subjects was studied, including 33 patients with AD, 31 patients with MCI, and 20 age-matched healthy controls (HC). A new quantitative index was calculated as a ratio of regional SUV of [¹⁸F]AV45 (normalized to cerebellar cortex) over the corresponding regional SUV of [¹⁸F]FDG, divided by the corresponding regional volume, measured from the co-registered MRI and normalized to the normal age-matched control group (AV45/FDG/NVol index). Relationships between clinical scores (TMSE, ADAS) and AV45/FDG/NVol indices for different structures of the brain in study groups were determined using linear regression analyses.

RESULTS

A significant direct linear correlation was observed between the AV45/FDG/NVol index and ADAS-Cog test score and an inverse correlation with TMSE score at baseline and with the degree of changes in ADAS and TMSE scores assessed one year later (disease progression). The observed correlations between AV45/FDG/NVol index and clinical scores were higher than those with MRI-based cortical volumes, FDG SUV, or cerebellum-normalized AV45 SUV alone.

CONCLUSIONS

Current study demonstrated that AV45/FDG/NVol index mapping of the brain is a novel quantitative molecular imaging biomarker that correlates with clinical neurocognitive status and may facilitate more accurate diagnosis, staging, and prognosis of AD. Additional larger scale clinical studies are required to further evaluate the efficacy of this new quantitative index as a diagnostic and prognostic biomarker of AD as well as for the evaluation of safety and efficacy of novel agents undergoing clinical trials for therapy of AD.

Comparison of Computerized and Standard Cognitive Test in Thai Memory Clinic

Background:

Computer-based Thai Cognitive Test or Computer-based Thai Mental State Examination (cTMSE) was developed aiming to help doctors to easily get the accurate results of TMSE in a routine, busy outpatient clinics. The purpose of this study was to compare the evaluation process in terms of feasibility, duration of the test, participants/administrator preference, and the results of cognitive test between cTMSE and the standard Thai Mental State Examination (sTMSE).

Methods:

Twenty-two elderly participants (>60 years old) who were not demented and 22 patients with mild-to-moderate dementia were included in the study. All participants would be asked to have TMSE by standard method (sTMSE) and computer-based method (cTMSE), at least 2 weeks and up to 2 months apart. Scores and duration of the test were compared using dependent paired t-test. Agreement of the tests between two methods and Kappa statistics were analyzed.

Results:

Paired t-test showed no significant difference in scores between the two methods (mean sTMSE vs. cTMSE: 22.84 vs. 22.62, 95% confidence interval [CI]: [−0.465] to 0.987, P = 0.524). Percent of agreement between the two methods was 92.5%, with the Kappa of 0.85 (P < 0.001). Duration of the test by sTMSE was slightly shorter than the cTMSE (7.31 min vs. 7.97 min, 95% CI: [−1.159] to [−0.175], P = 0.09). Overall, participants liked being tested by cTMSE more than sTMSE.

Conclusion:

Computer-based TMSE was feasible to use and accurate for screening in aging adults and for cognitive evaluation in patients with mild-to-moderate dementia.

Natural course and predictors of severe disability and death in Thai patients with dementia

More than half of patients with dementia lived in countries with low and middle incomes. However, there have been few studies on the natural course of disease in these countries. The purpose of this study was to study the natural course and the predictive factors of advanced stage and death in Thai patients with dementia. Patients with dementia who were treated in neurologic and psychiatric clinic from September 2004 to February 2016, were included. Data about natural course of diseases, behavioral and psychological symptoms in dementia (BPSD) and complications were studied. 207 patients were included. Mean age was 77years old. Mean Thai Mental State Examination (TMSE) was 17.5. Alzheimer's disease was the most common cause of dementia (55%). With the mean follow-up of 39months (range from 2 to 126months), 64% of the patients had BPSD. Sixty-two patients (30%) had complications required admission. Seven patients died. Fifty-four patients (29%) ended in the advanced stage of dementia. Mean duration from diagnosis to the advanced stage was 49months. Complications that required admission usually occurred in moderate to severe dementia and were strongly associated with the advanced stage or death (OR 6.1, 95%CI 2.57-14.49, p-value<0.0001). Alzheimer's disease was the most common cause of dementia in the study. Most demented patients presented in moderate severity of dementia. Mean duration from diagnosis to the advanced stage of dementia was approximate 4-5years. Complications required admissions related to the progression to advanced stage or death.

Alzheimer's disease with cerebrovascular disease: current status in the Asia-Pacific region

BACKGROUND

There is growing awareness of the coexistence of Alzheimer's disease and cerebrovascular disease (AD+CVD), however, due to lack of well-defined criteria and treatment guidelines AD+CVD may be underdiagnosed in Asia.

METHODS

Sixteen dementia specialists from nine Asia Pacific countries completed a survey in September 2014 and met in November 2014 to review the epidemiology, diagnosis and treatment of AD+CVD in Asia. A consensus was reached by discussion, with evidence provided by published studies when available.

RESULTS

AD accounts for up to 60% and AD+CVD accounts for 10-20% of all dementia cases in Asia. The reasons for underdiagnosis of AD+CVD include lack of awareness as a result of a lack of diagnostic criteria, misdiagnosis as vascular dementia or AD, lack of diagnostic facilities, resource constraints and cost of investigations. There is variability in the tools used to diagnose AD+CVD in clinical practice. Diagnosis of AD+CVD should be performed in a stepwise manner of clinical evaluation followed by neuroimaging. Dementia patients should be assessed for cognition, behavioural and psychological symptoms, functional staging and instrumental activities of daily living. Neuroimaging should be performed using computed tomography or magnetic resonance imaging. The treatment goals are to stabilize or slow progression as well as to reduce behavioural and psychological symptoms, improve quality of life and reduce disease burden. First-line therapy is usually an acetylcholinesterase inhibitor such as donepezil.

CONCLUSION

AD+CVD is likely to be under-recognised in Asia. Further research is needed to establish the true prevalence of this treatable and potentially preventable disease.