Advancements in dementia research, diagnostics, and care in Latin America: Highlights from the 2023 Alzheimer's Association International conference satellite symposium in Mexico City.

INTRODUCTION: While Latin America (LatAm) is facing an increasing burden of dementia due to the rapid aging of the population, it remains underrepresented in dementia research, diagnostics, and care. METHODS: In 2023, the Alzheimer's Association hosted its eighth satellite symposium in Mexico, highlighting emerging dementia research, priorities, and challenges within LatAm. RESULTS: Significant initiatives in the region, including intracountry support, showcased their efforts in fostering national and international collaborations; genetic studies unveiled the unique genetic admixture in LatAm; researchers conducting emerging clinical trials discussed ongoing culturally specific interventions; and the urgent need to harmonize practices and studies, improve diagnosis and care, and use affordable biomarkers in the region was highlighted. DISCUSSION: The myriad of topics discussed at the 2023 AAIC satellite symposium highlighted the growing research efforts in LatAm, providing valuable insights into dementia biology, genetics, epidemiology, treatment, and care.

Factors associated with functional decline in COVID-19 elderly survivors hospitalized in a tertiary care center.

BACKGROUND: The information on functional decline after hospitalization for COVID-19 is limited in older adults (OAs). OBJECTIVE: To determine the association of inflammation (ferritin) and coagulation markers (D-dimer) and clinical factors with the functional status of OAs who suffered from COVID-19 six months after hospital discharge in Mexico. MATERIAL AND METHODS: Ambispective cohort study of 158 patients older than 65 years hospitalized for moderate-severe COVID-19 with complete electronic records that would allow to collect information and to contact them six months after discharge. Functional impairment was defined as a decrease ≥ 10 points on the Barthel index. Using logistic regression analysis, the risk of association of biochemical and clinical factors with functional deterioration during follow-up was determined. RESULTS: 46.2% of participants exhibited functional decline. Associated factors included age ≥ 73 years (OR = 2.53), chronic kidney disease (OR = 4.57), an ABC-Goals score ≥ 8 (OR = 2.4), ferritin ≥ 605 ng/mL (OR = 3.94) and D-dimer ≥ 930 ng/mL (OR = 17.56). CONCLUSION: COVID-19 infection did not only represent a disease with a high risk of mortality during the acute phase, but is also associated with a high risk of functional impairment after hospital discharge.

ANTECEDENTES: La información acerca del deterioro funcional después de una hospitalización por COVID-19 es limitada en personas mayores (PM). OBJETIVO: Determinar la asociación entre marcadores de inflamación (ferritina), coagulación (dímero D), factores clínicos y el estado funcional de PM que padecieron COVID-19 a seis meses del alta hospitalaria en México. MATERIAL Y MÉTODOS: Estudio de cohorte ambispectiva de 158 pacientes mayores de 65 años hospitalizados por COVID-19 moderado-grave con expediente electrónico completo que permitiera recolectar información y contactarlos a los seis meses del alta. Se definió deterioro funcional como disminución ≥ 10 puntos del índice de Barthel. Mediante regresión logística se determinó el riesgo de asociación entre factores bioquímicos y clínicos y deterioro funcional en el tiempo de seguimiento. RESULTADOS: 46.2 % de los participantes presentó pérdida funcional. Los factores asociados fueron edad ≥ 73 años (RM = 2.53), enfermedad renal crónica (RM = 4.57), puntuación ABC-Goals ≥ 8 (RM = 2.4), ferritina ≥ 605 ng/mL (RM = 3.94) y dímero-D ≥ 930 ng/mL FEU (RM = 17.56). CONCLUSIÓN: La infección por COVID-19 no solo representa una enfermedad con alto riesgo de mortalidad durante la fase aguda, sino que también se asocia a un alto riesgo de deterioro funcional posterior al egreso hospitalario.

Association between vitamin B12 levels and cognitive impairment in older adults.

INTRODUCTION: Whether vitamin B12 deficiency is associated with cognitive impairment remains controversial. OBJECTIVE: To determine the association between vitamin B12 serum levels and cognitive performance. METHODS: Two-hundred and forty-one adults aged ≥ 60 years who had serum vitamin B12 serum levels measurement were included. Physical and cognitive evaluation was carried out, and three groups were formed: normal cognition (NC), mild cognitive impairment (MCI) and dementia. Vitamin B12 levels were classified as sufficiency (> 400 pg/mL), subclinical deficiency (201-400 pg/mL), and absolute deficiency (≤ 200 pg/mL). Multivariate linear regression analysis was used to evaluate the association between cognitive function and vitamin B12 levels after controlling for confounding variables. RESULTS: Mean age was 81.4 ± 8.0 years; 68% were females; 17.8 % and 39.8% had absolute and subclinical vitamin B12 deficiency, respectively; 80 individuals (33%) met the criteria for MCI, and 70 (29%), for dementia. Those with MCI and dementia had lower vitamin B12 levels in comparison with those with NC after adjusting for age, gender and educational level (p = 0.019). CONCLUSIONS: A statistically significant association was observed between global cognitive performance and levels of vitamin B12.

INTRODUCCIÓN: Aún es controversial si la deficiencia de vitamina B12 se asocia a alteraciones cognitivas. OBJETIVO: Conocer la asociación entre los niveles séricos de vitamina B12 y el desempeño cognitivo. MÉTODOS: Se incluyeron 241 personas ≥ 60 años con medición de niveles séricos de vitamina B12. Se realizó evaluación física y cognitiva y se formaron tres grupos: cognición normal (CN), deterioro cognitivo leve (DCL) y demencia. Los niveles de vitamina B12 se clasificaron en suficiencia (> 400 pg/mL), deficiencia subclínica (201-400 pg/mL) y deficiencia absoluta (≤ 200 pg/mL). Se realizó análisis de regresión lineal multivariado para evaluar la asociación entre función cognitiva y niveles de vitamina B12 después de controlar las variables confusoras. RESULTADOS: La media de edad fue 81.4 ± 8.0 años; 68 % fue del sexo femenino; 17.8 y 39.8 % presentaron deficiencia absoluta y subclínica de vitamina B12; 80 individuos (33 %) cumplieron los criterios de DCL y 70 (29 %), de demencia. Después de ajustar por edad, sexo y escolaridad, los sujetos con DCL y demencia tuvieron niveles más bajos de vitamina B12 comparados con aquellos con CN (p = 0.019). CONCLUSIONES: Se observó asociación estadísticamente significativa entre el desempeño cognitivo global y los niveles bajos de vitamina B12.

ASSOCIATION BETWEEN APOE-ε4 CARRIER STATUS AND QUALITATIVE NEUROIMAGING CHARACTERISTICS IN OLDER ADULTS WITH MILD COGNITIVE IMPAIRMENT.

BACKGROUND: The pathogenesis of mild cognitive impairment (MCI) is multifactorial and includes the presence of genetic variants such as the ε4 allele of the apolipoprotein E gene (APOE-ε4). Association between the APOE-ε4 carrier status and deleterious structural and functional changes on magnetic resonance imaging (MRI) has been previously described in individuals with Alzheimer's disease. However, the central nervous system changes may possibly develop in earlier stages of cognitive impairment, as reflected in MCI. OBJECTIVE: The objective of the study was to determine the association between APOE-ε4 carrier status and qualitative changes on MRI (medial temporal and parietal atrophy), as well as the detection of white matter hyperintensities (WMH) in older adults with MCI, in the memory clinic of a tertiary care hospital in Mexico City. METHODS: A cross-sectional study of 72 adults aged 60 years or above who underwent an exhaustive clinical, neuroimaging, and neuropsychological evaluation. Multivariate logistic regression models were constructed to determine the association between APOE-ε4 carrier status and qualitative/quantitative changes on MRI. RESULTS: Mean age was 75.2 years (± 7.2) and 64% were female. Twenty-one participants were cognitively normal and 51 had MCI. Almost 56% were APOE-ε4 carriers and were associated with medial-temporal atrophy according to the Scheltens scale (odds ratio [OR]: 20.0, 95% confidence intervals [CI]: 3.03-131.7), parietal atrophy according to the Koedam's score (OR: 6.3; 95% CI 1.03-39.53), and WMH according to the Fazekas scale (OR: 11.7, 95% CI: 1.26-108.2), even after adjusting for age, educational level, and cardiovascular risk factors. CONCLUSION: The APOE-ε4 carrier status was associated with medial temporal and parietal atrophy, as well as WMH. Our findings support the hypothesis suggesting the contribution of this genotype to neurodegeneration and cerebral vascular pathology.

Effect of poor glycemic control in cognitive performance in the elderly with type 2 diabetes mellitus: The Mexican Health and Aging Study.

BACKGROUND: Cognitive impairment is twice more frequent in elderly with type 2 diabetes mellitus (DM). This study was conducted to determine the association between glycemic control and cognitive performance among community-dwelling elderly persons in Mexico. METHODS: Cross-sectional study conducted in individuals aged 60 years or elderly participating in the 2012 Mexican Health and Aging Study. Type 2 DM participants were classified in 3 groups according to their glycated hemoglobin levels (HbA1c): < 7% (intensive control), 7-7.9% (standard control) or ≥ 8% (poor control), and cognitive performance: low (CCCE ≤44 points), intermediate (44.1-59.52 points), or high (≥59.53 points). Multinomial logistic regression models were constructed to determine this association. RESULTS: Two hundred sixteen community-dwelling adults aged 60 and older with type 2 diabetes were selected. Subjects in the low cognitive performance group were older (69.7 ± 6.6 vs 65.86 ± 5.18 years, p < .001) and had a lower educational level (2.5 ± 2.6 vs 7.44 ± 4.15 years, p < .000) when compared to the high cognitive performance participants. HbA1c ≥ 8% was associated with having low (Odds Ratio (OR) 3.17, 95% CI 1.17-8.60, p = .024), and intermediate (OR 3.23, 95% CI 1.27-8.20, p = .014) cognitive performance; this trend was not found for HbA1c 7.0-7.9% group. The multinomial regression analysis showed that the presence of HbA1c ≥ 8% (poor glycemic control) was associated with low (OR 3.17, 95% CI = 1.17-8.60, p = .024), and intermediate (OR 3.23, 95% CI = 1.27-8.20, p = .014) cognitive performance. After adjusting for confounding variables. CONCLUSIONS: Glycemic control with a HbA1c ≥ 8% was associated with worse cognitive performance.

ASSOCIATION OF VITAMIN D WITH MILD COGNITIVE IMPAIRMENT AND ALZHEIMER'S DEMENTIA IN OLDER MEXICAN ADULTS.

BACKGROUND: It has been proposed that Vitamin D helps reduce the accumulation of cerebral ß-amyloid-42 by innate immune stimulation and phagocytosis activation. An association between low Vitamin D levels and Alzheimer's dementia (AD) has been established. We determined the association between Vitamin D, mild cognitive impairment (MCI), and AD in older Mexican adults (> 65 years). METHODS: Cross-sectional study conducted at the memory clinic in a tertiary-level hospital in Mexico City. We evaluated subjects with MCI, AD, and normal cognition (NC) with available serum Vitamin D [25(OH)D] levels (past 6 months). Three categories were assigned according to 25(OH)D levels: sufficiency (> 30 ng/mL), insufficiency (21-29 ng/mL), and deficiency (≤ 20 ng/mL). Descriptive statistics, means and standard deviations were used. Logistic regression analyses adjusted by age, sex, and educational level were performed. RESULTS: We evaluated 208 patients. Mean age was 79 ± 1 year, 65% (n = 136) were female; and mean educational level was 6.7 ± 2.3 years. Thirty-one subjects (14%) had NC; 42% (n = 88) had MCI; and 43% (n = 89) had AD. Prevalence of Vitamin D deficiency was 54%, more frequent in the AD group (64%) followed by the MCI (59%) and NC (13%) (p < 0.001) groups. In the multivariate logistic regression analysis, Vitamin D deficiency was associated with MCI (HR 25.02 [confidence interval 95% 4.48-139]; p < 0.001) and AD (HR 41.7 [5.76-301]; p < 0.001) after adjusting for confounders. CONCLUSIONS: Serum Vitamin D deficiency was associated with MCI and dementia; low levels produced a greater effect over executive functions.

Clinical and Demographic Predictors of Conversion to Dementia in Mexican Elderly with Mild Cognitive Impairment.

BACKGROUND: Mild cognitive impairment (MCI) is considered a clinical stage between normal cognitive aging and dementia. The clinical course of MCI is heterogeneous, with a significant number of cases progressing to dementia or reverting back to normal. OBJECTIVE: To determine the predictors of conversion from mild cognitive impairment to dementia among Mexican older adults. MATERIALS AND METHODS: A sample of 175 persons underwent clinical and neuropsychological evaluation to establish mild cognitive impairment diagnosis. These patients were followed-up for a mean 3.5 years. RESULTS: Mean age was 81.7 (± 6.9) years, 57% were women, and mean education level was 9.5 (± 6.1) years. Sixty-one percent of mild cognitive impairment participants progressed to dementia. Multivariate Cox regression analysis showed that progression to dementia was associated with age (HR: 4.95; 95% CI: 1.96-12.46; p = 0.001), low education level (HR: 5.81; 95% CI: 1.90-7.78; p < 0.002), history of stroke (HR: 3.92; 95% CI: 1.37-11.16; p < 0.012) and cognitive decline (HR: 1.31; 95% CI: 1.18-1.45; p = 0.000). CONCLUSIONS: Age, poor education, cognitive decline, and a history of stroke were predictors of conversion to dementia. The identification and control of modifiable risk factors could influence conversion to dementia.

Frailty among Mexican community-dwelling elderly: a story told 11 years later. The Mexican Health and Aging Study.

OBJECTIVE: To describe the characteristics and prognosis of subjects classified as frail in a large sample of Mexican community-dwelling elderly. MATERIALS AND METHODS: An eleven-year longitudinal study of 5 644 old adults participating in the Mexican Health and Aging Study (MHAS). Frailty was defined by meeting at least three of the following criteria: weight loss, weakness, exhaustion, slow walking speed and low physical activity. The main outcomes were incident disability and death. Multiple covariates were used to test the prognostic value of frailty. RESULTS: Thirty-seven percent of participants (n= 2 102) met the frailty criteria. Frail participants were significantly older, female, less educated, with more chronic disease, lower income, and poorer self-reported health status, in comparison with their non-frail counterparts. Frailty was a predictor both for disability activities of daily living and for mortality. CONCLUSION: After a follow-up of more than ten years, the phenotype of frailty was a predictor for adverse health-related outcomes, including ADL disability and death.

Brain health index as a predictor of possible vascular dementia in the Mexican health and aging study 2012-2015.

To determine the burden of disease among subjects at risk of developing stroke or dementia, brain health indexes (BHI) tend to rely on anatomical features. Recent definitions emphasize the need of a broader perspective that encompasses cardiovascular risk factors (CVRFS) and lifestyle components which can be considered partial contributors to optimal brain health. In this study, we aimed to establish the association and risk detected by a Brain Health Index and the risk of possible vascular dementia (PVD) using data from the Mexican Health and Aging Study (MHAS) 2012-2015. The MHAS is a longitudinal study of adults aged ≥ 50 years. We analyzed the data obtained between 2012 and 2015. CVRFS included in the index were diabetes mellitus, hypertension, myocardial infarction, depression, obesity, physical inactivity, and smoking history. A PVD diagnosis was established when scores in the Cross-Cultural Cognitive Examination were below reference norms and limitations in ≥1 instrumental activities of daily living and a history of stroke were present. A multinomial regression model was developed to determine the association between BHI scores and PVD. In 2015, 75 PVD cases were identified. Mean age was 67.1 ±13.2 years, 35.8% were female, and the mean educational level was 5.8 ±5.5 years. In cases with a higher score in the BHI, the model revealed a hazards ratio of 1.63 (95% CI: 1.63-1.64, p< 0.001) for PVD. In this longitudinal study, with the use of a feasible multifactorial BHI in the Mexican population, a greater score was associated with a 1.63-fold risk of developing PVD during the 3-year follow-up, while the risk for stroke was 1.75. This index could potentially be used to predict the risk of PVD in adults with modifiable CVRFS.

Prevalence of Dementia and Main Subtypes in Mexico: The Study on Aging and Dementia in Mexico (SADEM).

BACKGROUND: Dementia is a priority public health issue due to its high prevalence worldwide and its economic, social, and health impact. However, there are few reports in Mexico based on formal tests and with a clinical approach based on the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5). OBJECTIVE: This study estimates the prevalence of the main types of dementia among elderly people living in the community in Mexico City. METHODS: A population-based, two-step study was conducted, including 6,204 elderly individuals aged 60 or above with in-home assessment. All participants were screened for cognitive impairment; those who presented some cognitive problem underwent a standardized neurological examination. Each diagnosis was based on the criteria for dementia in the DSM-5, and the final consensus diagnosis of dementia was determined by an expert panel. RESULTS: The global estimated prevalence of dementia in the Mexican population was 7.8% met the criteria for Alzheimer's disease, 4.3% for vascular dementia, and 2.1% for mixed dementia. The prevalence of dementia was higher in women than in men (15.3% versus 12.5%, respectively). CONCLUSION: These results provide evidence to propose strategies for Latin American countries where dementia represents a challenge due to the heterogeneity of the populations and socioeconomic disparities, requiring early diagnosis and at the first levels of care.

Association between ApoE ε4 Carrier Status and Cardiovascular Risk Factors on Mild Cognitive Impairment among Mexican Older Adults.

Mild cognitive impairment (MCI) (amnestic or non-amnestic) has different clinical and neuropsychological characteristics, and its evolution is heterogeneous. Cardiovascular risk factors (CVRF), such as hypertension, diabetes, or dyslipidemia, and the presence of the Apolipoprotein E ε4 (ApoE ε4) polymorphism have been associated with an increased risk of developing Alzheimer's disease (AD) and other dementias but the relationship is inconsistent worldwide. We aimed to establish the association between the ApoE ε4 carrier status and CVRF on MCI subtypes (amnestic and non-amnestic) in Mexican older adults. Cross-sectional study including 137 older adults (n = 63 with normal cognition (NC), n = 24 with amnesic, and n = 50 with non-amnesic MCI). Multinomial logistic regression models were performed in order to determine the association between ApoE ε4 polymorphism carrier and CVRF on amnestic and non-amnestic-MCI. ApoE ε4 carrier status was present in 28.8% participants. The models showed that ApoE ε4 carrier status was not associated neither aMCI nor naMCI condition. The interaction term ApoE ε4 × CVRF was not statistically significant for both types of MCI. However, CVRF were associated with both types of MCI and the association remained statistically significant after adjustment by sex, age, and education level. The carrier status of the ApoE genotype does not contribute to this risk.

The Social Vulnerability Index, Mortality and Disability in Mexican Middle-Aged and Older Adults.

The social vulnerability index (SVI) independently predicts mortality and others adverse outcomes across different populations. There is no evidence that the SVI can predict adverse outcomes in individuals living in countries with high social vulnerability such as Latin America. The aim of this study was to analyze the association of the SVI with mortality and disability in Mexican middle-aged and older adults. This is a longitudinal study with a follow-up of 47 months, the Mexican Health and Aging Study, including people over the age of 40 years. A SVI was calculated using 42 items stratified in three categories low (<0.36), medium (0.36-0.47), and high (>0.47) vulnerability. We examined the association of SVI with three-year mortality and incident disability. Cox and logistic regression models were fitted to test these associations. We included 14,217 participants (58.4% women) with a mean age of 63.9 years (±SD 10.1). The mean SVI was of 0.42 (±SD 0.12). Mortality rate at three years was 6% (n = 809) and incident disability was 13.2% (n = 1367). SVI was independently associated with mortality, with a HR of 1.4 (95% CI 1.1-1.8, p < 0.001) for the highest category of the SVI compared to the lowest. Regarding disability, the OR was 1.3 (95% CI 1.1-1.5, p = 0.026) when comparing the highest and the lowest levels of the SVI. The SVI was independently associated with mortality and disability. Our findings support previous evidence on the SVI and builds on how this association persists even in those individuals with underlying contextual social vulnerability.

Five-Word Test, Screening of Mixed Dementia in Older Adults. Validation Study.

INTRODUCTION AND OBJECTIVES: The prevalence of mixed dementia (MixD), defined as the coexistence of Alzheimer's disease (AD) and vascular dementia (VaD), is likely to increase as the population ages. The five-word test (5WT) is a neuropsychological test that differentiates between major and mild neurocognitive disorder (NCD). The objective of the study is to validate 5WT for the detection of MixD. METHODS: 230 participants were evaluated: cognitively healthy (CH) (n=70), mild NCD (n=70), and major NCD (n=90): AD (n=30), VaD (n=30), and MixD (n=30). The Spearman's coefficient, d Sommer and ROC curves were used to determine the construct validity of the 5WT. The linear regression model was performed to determine the association between age and education with 5WT performance. RESULTS: The mean age was 79 ±7.7 years (P≤.001), 58% were female (P=.252), and the mean education was 9 ±5.3 years (P≤.001). Construct validity when comparing 5WT and MMSE was: Spearman's correlation ρ=.830 (P<.001) and d Sommer=.41 (P<.001). The area under the curve in the total weighted score (TWS) for MixD was .985, with 98% sensitivity (95%CI, 0.96-1.00) and 99% specificity (95%CI, 0.94-1.00), PPV of 88% (95%CI, 0.82-0.89), NPV of 100% (95%CI, 0.96-1.00), and cut-off point ≤16/20 (P<.001). CONCLUSIONS: 5WT is a rapid test with neuropsychological validation for the exploration of cognitive characteristics in major NCD type MixD, regardless of age and education.

Prevalence and incidence of possible vascular dementia among Mexican older adults: Analysis of the Mexican Health and Aging Study.

INTRODUCTION: Vascular dementia is the second most common cause of dementia. Physical disability and cognitive impairment due to stroke are conditions that considerably affect quality of life. We estimated the prevalence and incidence of possible vascular dementia (PVD) in older adults using data from the Mexican Health and Aging Study (MHAS 2012 and 2015 waves). METHODS: The MHAS is a representative longitudinal cohort study of Mexican adults aged ≥50 years. Data from 14, 893 participants from the 2012 cohort and 14,154 from the 2015 cohort were analyzed to estimate the prevalence and incidence of PVD. Self-respondents with history of stroke were classified as PVD if scores in two or more cognitive domains in the Cross-Cultural Cognitive Examination were ≥ 1.5 standard deviations below the mean on reference norms and if limitations in ≥ 1 instrumental activities of daily living were present. For proxy respondents with history of stroke, we used a score ≥3.4 on the Informant Questionnaire on Cognitive Decline in the Elderly. Crude and standardized rates of prevalent and incident PVD were estimated. RESULTS: Prevalence of PVD was 0.6% (95% CI, 0.5-0.8) (0.5 with age and sex- standardization). Rates increased with age reaching 2.0% among those aged 80 and older and decreased with educational attainment. After 3.0 years of follow-up, 87 new cases of PVD represented an overall incident rate of 2.2 (95% CI, 1.7-2.6) per 1,000 person-years (2.0 with age and sex- standardization). Incidence also increased with advancing age reaching an overall rate of 9.4 (95% CI, 6.3-13.6) per 1,000 person-years for participants aged >80 years. Hypertension and depressive symptoms were strong predictors of incident PVD. CONCLUSION: These data provide new estimates of PVD prevalence and incidence in the Mexican population. We found that PVD incidence increased with age. Males aged 80 years or older showed a greater incidence rate when compared to females, which is comparable to previous estimates from other studies.

Comparison of the Impact of Zika and Dengue Virus Infection, and Other Acute Illnesses of Unidentified Origin on Cognitive Functions in a Prospective Cohort in Chiapas Mexico.

Zika has been associated with a variety of severe neurologic manifestations including meningitis and encephalitis. We hypothesized that it may also cause mild to subclinical neurocognitive alterations during acute infection or over the long term. In this observational cohort study, we explored whether Zika cause subclinical or mild neurocognitive alterations, estimate its frequency and duration, and compare it to other acute illnesses in a cohort of people with suspected Zika infection, in the region of Tapachula in Chiapas, Mexico during 2016-2018. We enrolled patients who were at least 12 years old with suspected Zika virus infection and followed them up for 6 months. During each visit participants underwent a complete clinical exam, including a screening test for neurocognitive dysfunction (Montreal Cognitive Assessment score). We enrolled 406 patients [37 with Zika, 73 with dengue and 296 with other acute illnesses of unidentified origin (AIUO)]. We observed a mild and transient impact over cognitive functions in patients with Zika, dengue and with other AIUO. The probability of having an abnormal MoCA score (<26 points) was significantly higher in patients with Zika and AIUO than in those with dengue. Patients with Zika and AIUO had lower memory scores than patients with dengue (Zika vs. Dengue: -0.378, 95% CI-0.678 to -0.078; p = 0.014: Zika vs. AIUO 0.264, 95% CI 0.059, 0.469; p = 0.012). The low memory performance in patients with Zika and AIUO accounts for most of the differences in the overall MoCA score when compared with patients with dengue. Our results show a decrease in cognitive function during acute illness and provides no evidence to support the hypothesis that Zika might cause neurocognitive alterations longer than the period of acute infection or different to other infectious diseases. While effects on memory or perhaps other cognitive functions over the long term are possible, larger studies using more refined tools for neurocognitive functioning assessment are needed to identify these. Trial Registration: NCT02831699.

Cerebral Vascular Reactivity in Frail Older Adults with Vascular Cognitive Impairment.

Background: Frailty, a state of increased vulnerability, could play a role in the progression of vascular dementia. We aim to describe the changes in cerebrovascular reactivity of older adults with frailty and vascular-type mild cognitive impairment (MCIv). Methods: This was a cross-sectional study. A comprehensive geriatric assessment, neuropsychological evaluation, and transcranial Doppler ultrasound (TCD) was performed on 180 participants who were allocated into four groups: healthy (n = 74), frail (n = 40), MCIv (n = 35), and mixed (frail + MCIv) (n = 31). ANOVA and Kruskal-Wallis tests were used for the analysis of continuous variables with and without normal distribution. Multinomial logistic regression was constructed to identify associated covariates. Results: Subjects in the mixed group, compared to healthy group, were older (75.0 ± 5.9 vs 70.3 ± 5.9 years; p < 0.001), showed lower education (9.3 ± 6.4 vs 12.2 ± 4.0 years; p = 0.054), greater frequency of diabetes (42% vs 12%; p = 0.005), worse cognitive performance (z = -0.81 ± 0.94), and reduced left medial-cerebral artery cerebrovascular reactivity (0.43 ± 0.42 cm/s). The mixed group was associated with age (odds ratio (OR) 1.16, 95% Confidence Interval (CI) = 1.06-1.27; p < 0.001), diabetes (OR 6.28, 1.81-21.84; p = 0.004), and Geriatric Depression Scale (GDS) score (OR 1.34, 95% CI = 1.09-1.67; p = 0.007). Conclusions: Frailty among older adults was associated with worse cognitive performance, diabetes, and decreased cerebral blood flow.

Factores asociados al deterioro funcional en adultos mayores sobrevivientes de COVID-19 hospitalizados en un centro de tercer nivel / Factors associated with functional decline in COVID-19 elderly survivors hospitalized in a tertiary care center

Resumen Antecedentes: La información acerca del deterioro funcional después de una hospitalización por COVID-19 es limitada en personas mayores (PM). Objetivo: Determinar la asociación entre marcadores de inflamación (ferritina), coagulación (dímero D), factores clínicos y el estado funcional de PM que padecieron COVID-19 a seis meses del alta hospitalaria en México. Material y métodos: Estudio de cohorte ambispectiva de 158 pacientes mayores de 65 años hospitalizados por COVID-19 moderado-grave con expediente electrónico completo que permitiera recolectar información y contactarlos a los seis meses del alta. Se definió deterioro funcional como disminución ≥ 10 puntos del índice de Barthel. Mediante regresión logística se determinó el riesgo de asociación entre factores bioquímicos y clínicos y deterioro funcional en el tiempo de seguimiento. Resultados: 46.2 % de los participantes presentó pérdida funcional. Los factores asociados fueron edad ≥ 73 años (RM = 2.53), enfermedad renal crónica (RM = 4.57), puntuación ABC-Goals ≥ 8 (RM = 2.4), ferritina ≥ 605 ng/mL (RM = 3.94) y dímero-D ≥ 930 ng/mL FEU (RM = 17.56). Conclusión: La infección por COVID-19 no solo representa una enfermedad con alto riesgo de mortalidad durante la fase aguda, sino que también se asocia a un alto riesgo de deterioro funcional posterior al egreso hospitalario.

Abstract Background: The information on functional decline after hospitalization for COVID-19 is limited in older adults (OAs). Objective: To determine the association of inflammation (ferritin) and coagulation markers (D-dimer) and clinical factors with the functional status of OAs who suffered from COVID-19 six months after hospital discharge in Mexico. Material and methods: Ambispective cohort study of 158 patients older than 65 years hospitalized for moderate-severe COVID-19 with complete electronic records that would allow to collect information and to contact them six months after discharge. Functional impairment was defined as a decrease ≥ 10 points on the Barthel index. Using logistic regression analysis, the risk of association of biochemical and clinical factors with functional deterioration during follow-up was determined. Results: 46.2 % of participants exhibited functional decline. Associated factors included age ≥ 73 years (OR = 2.53), chronic kidney disease (OR = 4.57), an ABC-Goals score ≥ 8 (OR = 2.4), ferritin ≥ 605 ng/mL (OR = 3.94) and D-dimer ≥ 930 ng/mL (OR = 17.56). Conclusion: COVID-19 infection did not only represent a disease with a high risk of mortality during the acute phase, but is also associated with a high risk of functional impairment after hospital discharge.

Validity and Reliability of the Spanish Version of the Montreal Cognitive Assessment (MoCA) for the Detection of Cognitive Impairment in Mexico. / Validez y confiabilidad del MoCA (Montreal Cognitive Assessment) para el tamizaje del deterioro cognoscitivo en méxico.

OBJECTIVE: To establish the validity and reliability of the Montreal Cognitive Assessment in Spanish (MoCA-S) to identify mild cognitive impairment (MCI) and dementia in the Mexican elderly population. MATERIAL AND METHODS: 168 participants from a memory clinic in Mexico City were enrolled and divided into 3 groups: 59 cognitively healthy (CHG), 52 with mild cognitive impairment (MCI) (DSM-5 criteria) and 57 with dementia (NINCDS-ADRDA criteria). The MoCA-S and Mini-Mental State Evaluation (MMSE) were applied at baseline and during the last months to establish intra-observer reliability. ROC curves and a multinomial regression model were constructed to evaluate the effect of age and education on MoCA-S performance. RESULTS: The mean age of the participants was 76±8.1 years and the education rate was 10.7±5.2. The MoCA-S scores by group were: CHG, 27.3±1.9; MCI, 22.9±2.9; and dementia, 13.7±4.9 (p<0.001). The reliability of the MoCA-S was 0.89 and the intraclass correlation coefficient was 0.955. Sensitivity was 80% and specificity was 75%, with a cut-off point of 26 points for MCI (area under the curve, 0.886; p<0.001). For the dementia group, the sensitivity was 98% and specificity was 93%, with a cut-off point of 24points (area under the curve, 0.998; p<0.001). The multinomial regression showed no association with education and age for both the MCI and dementia groups. CONCLUSIONS: The MoCA-S is a valid and reliable instrument for MCI and dementia screening in the Mexican population, even after adjusting for age and education.

Neuroimaging Characteristics of Small-Vessel Disease in Older Adults with Normal Cognition, Mild Cognitive Impairment, and Alzheimer Disease.

INTRODUCTION: Cerebral small-vessel disease (SVD) represents the most frequent type of vascular brain lesions, often coexisting with Alzheimer disease (AD). By quantifying white matter hyperintensities (WMH) and hippocampal and parietal atrophy, we aimed to describe the prevalence and severity of SVD among older adults with normal cognition (NC), mild cognitive impairment (MCI), and probable AD and to describe associated risk factors. METHODS: This study included 105 older adults evaluated with magnetic resonance imaging and clinical and neuropsychological tests. We used the Fazekas scale (FS) for quantification of WMH, the Scheltens scale (SS) for hippocampal atrophy, and the Koedam scale (KS) for parietal atrophy. Logistic regression models were performed to determine the association between FS, SS, and KS scores and the presence of NC, MCI, or probable AD. RESULTS: Compared to NC subjects, SVD was more prevalent in MCI and probable AD subjects. After adjusting for confounding factors, logistic regression showed a positive association between higher scores on the FS and probable AD (OR = 7.6, 95% CI 2.7-20, p < 0.001). With the use of the SS and KS (OR = 4.5, 95% CI 3.5-58, p = 0.003 and OR = 8.9, 95% CI 1-72, p = 0.04, respectively), the risk also remained significant for probable AD. CONCLUSIONS: These results suggest an association between severity of vascular brain lesions and neurodegeneration.