Ana Luisa Sosa-Ortiz

Epidemiology of Dementias and Alzheimer's Disease

BACKGROUND AND AIMS Global population aging has been one of the defining processes of the twentieth century, with profound economic, political and social consequences. It is driving the current epidemic of dementia, both in terms of its extent and global distribution. The aim of the study was to summarize recent findings relevant to the epidemiological knowledge of dementia and Alzheimers disease (AD). METHODS A narrative mini-review of the literature relevant to the epidemiology of dementia and AD is presented, summarizing important findings and analyzing their implications. RESULTS It was estimated that in 2010 there were 36.5 million people living with dementia, with 7.7 million new cases yearly and a new case of dementia every 4 sec. The number of persons living with dementia will nearly double every 20 years. Most of these persons will be living in low- and middle-income countries (LMIC). CONCLUSIONS There are a substantial number of people with dementia worldwide and these numbers will continue to increase mainly in LMIC, producing a wide range of impacts. It is important to make dementia a national public health and social care priority worldwide. Recent reviews and meta-analyses have failed to clearly identify a singular causal or preventive pathway for AD that seems to be a multicausal, heterogeneous and age-related condition.

The association between social support and cognitive function in Mexican adults aged 50 and older

Social support networks are crucial for the health of older adults; however, personal characteristics and time of life may diminish the protective effect of social support. OBJECTIVE to determine if the presence of social support networks were associated with cognitive impairment among Mexican adults aged 50 or older and if this relationship was different based on age. METHOD This study analyzed data from the National Representation Survey performed in Mexico, Study on Global Ageing (SAGE) wave 1. Cognitive function was evaluated by a standardized test, social support was evaluated through latent class analysis (LCA). The LCA was run to obtain three subgroups of different Social Support Levels (SSL): low, medium, and high. Logistic regression models, stratified by age, were performed to analyze the association between SSL and cognitive function. RESULTS For respondents ages 71-80 y/o, there was an inverse relationship with cognitive impairment for those with medium (OR 0.23, p=0.020) and high (OR 0.07, p=0.000) SSL in comparison with low SSL. While social support helped to improve cognitive function in older adults aged 71-80, this same association was not observed in adults of other ages. Those younger than 70 y/o may not need such a strong support network as a result of being more self-sufficient. After 80, social networks were not enough to help diminish the negative impact of cognitive impairment. CONCLUSION Social support could improve the cognitive function of adults ages 71 and 80; suggesting there could be a window of opportunity to improve cognitive functioning for this group.

Fluidez verbal-semántica en adultos mayores mexicanos: valores normativos

INTRODUCTION The semantic verbal fluency test (SVF) is sensitive to detecting cognitive decline. It is fast and easy to use in any cultural context; therefore, it is included in most of the neuropsychological assessment protocols. OBJECTIVE To estimate normative values for the SVF test (animals), in an elderly population aged 65 years and over. MATERIAL AND METHOD 1233 subjects who were healthy, cognitively preserved, residents of two areas (rural and urban) of Mexico were assessed. A neurological and neuropsychological exploration battery was applied, including SVF. RESULTS The age average was 73+6 and schooling was 4.0+3.9 years, with 59% women. The average of the words generated in the SVF test was 14+5, and a correlation of 0.16 of these scores with age, education, and gender was found (p<.001), this allowed the estimation of the percentiles in accordance with these variables. CONCLUSIONS The most important contribution provided by this study was that the data analysis enabled normative values to be obtained for an elderly Mexican population aged 65 years and over. It was also confirmed, as other neuropsychological assessment studies have done, that the SVF test is influenced by socio-demographic variables, such as age and education, aspects to be considered at the time of obtaining normative values. Finally, it was noted that the average scores obtained were lower than other published reference values, due to the low educational level of our sample.

Factors associated with cognitive function in older adults in Mexico

Background As populations age, cognitive decline and dementia pose significant burdens for societies and health care systems, including low- and middle-income countries such as Mexico. Minor age-related declines in cognitive function appear to represent a stable but heterogeneous phase in the continuum between normal cognitive ageing and dementia. Loss of cognitive function has impacts at societal and individual levels and understanding the risk factors can help provide a framework for health policies and interventions to target at-risk groups. Design A cohort of older Mexican adults (50+) from the World Health Organizations Study on global AGEing and adult health (WHO SAGE) was used to examine cognitive function, including a total of 2315 respondents, with 325 respondents aged 80 years and older. Cognition was objectively evaluated using verbal recall, verbal fluency, forward digit span and backward digit span, with differences in an overall cognitive score assessed against sociodemographic variables, and associated factors using linear regression. Results The most significant predictors of poorer cognitive function were found to be older age (β=−13.88), rural living (β=−2.25), low income (β=−8.28), self-reported severe or extreme memory difficulties (β=−6.62), and difficulty with two or more activities of daily living (β=−2.02). Conclusions These findings can inform public health initiatives to address cognitive impairment in ageing populations in Mexico and other middle-income countries.

LOWER GAIT SPEED IS INDEPENDENTLY ASSOCIATED WITH INCREASED MORTALITY RISK AMONG PEOPLE WITH DEMENTIA IN LOW- AND MIDDLE-INCOME COUNTRIES: RESULTS FROM THE 10/66 DEMENTIA RESEARCH GROUP POPULATION-BASED COHORT STUDY

mance was investigated in stable and declined participants. Methods: Participants (n1⁄4123, 70.366.0 years, 61% men, out of the Heinz Nixdorf Recall study) performed neuropsychological andMR-tomographic tests twicewithin 2.560.2 years. Participants were classified as “cognitively healthy”, “mildly cognitively impaired” (MCI) or “demented” at both time points. Participants who did not change over time were classified as “stable”, those who changed from “cognitively healthy” to “MCI” or from “MCI” to “demented” were classified as “declined”. Annualized percentage volume changes of HC, TL, and the whole brain were determined by atlas-based MRI volumetry, an investigator-independent method using SPM algorithms. All volumetric data were adjusted for intracranial volume. Group comparisons were performed using covariance analysis adjusted for age, gender and education. The association of percentage volume changes and change in cognitive performance were examined using linear regression models adjusted for age, gender and education in both groups. Results: Cognitively declined participants showed more volume loss in the HC (stable: 0.12% 6 1.82 SD; declined: -2.31% 6 1.87 SD), TL (stable: -0.75% 6 0.90 SD; declined: -1.75% 6 0.93 SD) and in the whole brain (stable: -0.78% 6 0.74 SD; declined: -1.40% 6 0.76 SD). Furthermore, change in cognitive performance was strongly associated with change in hippocampal volume in the declined group (R1⁄4 42.6%, b1⁄4 0.659, B1⁄42.487; 95% confidence interval (0.77;4.20), p1⁄40.008) but not in the stable group (R1⁄4 1.8%, b1⁄4 -0.093, B1⁄4-0.142; 95% confidence interval (-0.44;-0.16), p1⁄40.35). Conclusions:This study shows that volume changes of HC, TL and the whole brain are potential biomarkers for cognitive deficits. Our results support previous studies regarding the predictive value of HC volume for cognitive performance in a population-based setting.

POSITIVE IMPACT OF SPEECH THERAPY IN PROGRESSIVE NON-FLUENT APHASIA

The aim of this paper is to analyze the effects of intensive speech therapy intervention in a case of progressive non-fluent aphasia (PNFA). This is a dementia syndrome characterized by a progressive deficit in expressive language fluency and syntactic analysis, and by agrammatism and phonemic paraphasias. Although in the early stages there are no alterations in memory, comprehension, or visual processing, personality changes can slightly occur. To analyze the effects of speech therapy in this syndrome, a single case design with pre- and post-test was used. The participant was a male patient of 84 years with PNFA, who for twelve months received weekly speech therapy to stimulate the phonological, lexical and syntactic processing. He underwent neuropsychological assessment in three stages: six months before the onset of therapy, six months after therapy started and after completing 12 months of intervention. Assessment involved linguistic processing, general cognition, neuropsychiatric symptoms, quality of life (QOL) and activities of daily living (ADL). As a result of therapy, the patient showed a slight improvement in language prosody, fluency, and content of spontaneous speech, and a significant improvement in repetition, reading aloud, and oral-phonatory praxis. Other aspects of cognitive functioning (orientation, verbal naming, praxis, and memory) remained stable; ADLs and QOL improved. It is concluded that prolonged speech therapy can improve language processing and have a positive impact on other cognitive and socio-emotional processes in PNFA. This 12-month therapeutic stimulation not only slowed cognitive decline, but allowed to see maintenance of achievements and improvement of symptoms, which can be regarded as a success in PNFA treatment, considering the rapid progression of the disease.

Work status, retirement, and depression in older adults: An analysis of six countries based on the Study on Global Ageing and Adult Health (SAGE)

The aim of the present study was to analyse the association between the occurrence of a major depressive episode among older adults and work status in low- and medium-income countries. A cross-sectional study was conducted with people 60 years of age and older from the six countries (Mexico, India, China, Russian Federation, Ghana and South Africa) included in the Study on Global Ageing and Adult Health (SAGE) and who participated in its first wave (2009–2010). The occurrence of a major depressive episode (MDE) over the previous 12 months was determined based on an adaptation of the ICD-10 diagnostic criteria. The association between current work status and the presence of an MDE was estimated using binary logistic regression models with country-level fixed effects, and interaction terms between the country and work status. Results showed the odds of presenting an MDE were lower for older adults who were retired with a pension than for those who were currently working, although this protective association was observed only for men in China (OR=0.23; CI 95%:0.08–0.70) and Ghana (OR=0.25; CI 95%:0.07–0.95) and for women in India (OR=0.05; CI 95%:0.01–0.51) and South Africa (OR=0.19; CI 95%:0.04–0.97). For women, being a homemaker also showed a protective association in South Africa (OR=0.09; CI95%:0.01–0.66) and Mexico (OR=0.32; CI95%:0.14–0.76). In the case of being retired without a pension, no significant association was found in any country. The previous indicates that retirement with pension has a protective association with MDE only for men in China and Ghana and women in India and South Africa. The heterogeneity of this association reflects cultural and socioeconomic differences between the analysed countries.

Exposure to ambient PM 2.5 concentrations and cognitive function among older Mexican adults

BACKGROUND Recent epidemiological research has shown that exposure to fine particulate pollution (PM2.5) is associated with a reduction in cognitive function in older adults. However, primary evidence comes from high-income countries, and no specific studies have been conducted in low and middle-income countries where higher air pollution levels exist. OBJECTIVES To estimate the association between the exposure to PM2.5 and cognitive function in a nationally representative sample of older Mexican adults and the associated effect modifiers. METHODS Data for this study were taken from the National Survey of Health and Nutrition in Mexico carried out in 2012. A total of 7986 older adults composed the analytical sample. Cognitive function was assessed using two tests: semantic verbal fluency and three-word memory. The annual concentration of PM2.5 was calculated using satellite data. Association between exposure to PM2.5 and cognitive function was estimated using two-level logistic and linear regression models. RESULTS In adjusted multilevel regression models, each 10 μg/m3 increase in ambient PM2.5 raised the odds of a poorer cognitive function using the three-word memory test (OR = 1.37, 95% CI: 1.08, 1.74), and reduced the number of valid animal named in the verbal fluency test (β = -0.72, 95% CI: -1.05, -0.40). Stratified analyses did not yield any significant modification effects of age, sex, indoor pollution, urban/rural dwelling, education, smoking and other factors. CONCLUSIONS This study supports an association between exposure to PM2.5 concentrations and cognitive function in older adults. This is particularly relevant to low- and middle-income countries, which are marked by a rapid growth of their aging population and high levels of air pollution.

VALIDITY AND RELIABILITY OF THE 10/66 DEMENTIA RESEARCH GROUP COGNITIVE TEST BATTERY FOR EARLY IDENTIFICATION OF COGNITIVE DECLINE IN MEXICO

to test the null hypothesis of no mean difference between delayed recall memory T-scores and language and executive function, respectively. Results: This pre-dialysis sample included 27 adults with a mean age of 66, a mean education of 13 years, and a mean estimated glomerular filtration rate (eGFR, in ml/min/1.73 m) of 13; the average length of time between the last study visit and participant report of dialysis initiation was 6 months. Delayed recall memory performance was the only measure, on average, which fell in the impaired range (T < 40) and demonstrated the lowest performance (T1⁄4 37.9) compared to both language (T 1⁄4 43.7; p 1⁄4 .03) and executive function (T 1⁄4 43.2; p 1⁄4 .05). Conclusions: Delayed recall memory performance may be preferentially reduced in advanced CKD patients prior to the initiation of HD. Future studies will investigate the pattern of pre-dialysis cognitive performance in a larger sample, further characterize the course of memory changes throughout HD, and determine whether impairment in this domain prior to HD suggests an irreversible neurodegenerative process that may not improve with HD treatment.

EEG THETA OSCILLATIONS AS A POTENTIAL BIOMARKER FOR EXECUTIVE DYSFUNCTION IN NEURODEGENERATIVE DISORDERS: A SYSTEMATIC REVIEW WITH META-ANALYSIS

a trend towards a longitudinal increase (T1 versus T2 p1⁄40.055, T2 versus T3 p1⁄40.78, T1 versus T3 p1⁄40.013, respectively). This significant trend was present in the AbPET+ group compared to the AbPETgroup. None of the other plasma biomarkers was associated with YKL-40, both at baseline and longitudinal investigations. Conclusions: Plasma YKL-40 concentrations in SMC participants increase overtime in the presence of cerebral Ab accumulation, indicating that neuroinflammation across brain amyloidosis can be peripherally detected. Plasma YKL-40 concentrations are increased in males, suggesting a potential influence of sex on astrocytic/microglial activation. Conversely, plasma YKL-40 concentrations are not impacted by APOE status and cerebral Ab accumulation.