Cognitive function in Mexican older adults 6-months after recovering from SARS-CoV-2 infection.

BACKGROUND: SARS-CoV-2 infection has been associated with multiple short- and long-term complications including depression, and cognitive impairment (CI). However, older adults with CI after COVID-19 have not been fully documented. OBJECTIVE: To evaluate cognitive function in Mexican adults post-recovery from SARS-CoV-2 infection. METHODS: In this prospective observational cohort study, we assess cognitive function (CF) by the Montreal Cognitive Assessment (MOCA) test with a cut-off less than 26 points, and functional status via telemedicine. Eligible patients with a history of moderate-severe COVID-19 aged ≥60 years, cognitively healthy (evaluated by Everyday Cognition Scale) and required admission to an intensive care unit (ICU) were included. Patients with history of dementia, stroke, and delirium during the cognitive evaluation were excluded. The association between CI and COVID-19 was assessed with a Cox regression model. RESULTS: From the 634 patients admitted to the ICU, 415 survived, afterward 308 were excluded and 107 were analyzed. Mean age was 70 years, 58% were female, and 53% had severe COVID. The mean MoCA score was 21±5 points, CI was present in 61 patients (57%). Infection severity (RR 1.87; 95% CI: 1.11-3.15, p<0.05), lower education (RR 0.92; 95% CI: 0.87-0.97, p<0.01), and activity daily living disability (RR 1.87; 95% CI: 1.07-3.26, p<0.05) were the main factors associated with CI (unadjusted model by age and sex). The delayed recall, orientation, and language (83.2, 77.6 and 72.9% respectively) domains were the most affected in patients with CI. CONCLUSIONS: Fifty-seven percent of patients analyzed developed CI six months post-ICU discharge due to SARS-CoV-2, and COVID severity was the main factor associated to its outcome.

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.

The Mex-Cog cognitive assessment battery: discriminant analysis of the cognitive performance profile in older adults.

OBJECTIVE: To analyze the cognitive profile of a clinical sample using the Mex-Cog cognitive battery and establish which cognitive measures and domains contribute most to group separation. MATERIALS AND METHODS: A group of 145 older adults previously diagnosed with dementia (n= 47), mild cognitive impairment MCI (n= 47), or as cognitively normal (n= 51) were assessed with the Mex-Cog cognitive battery. Six linear discriminant analyses (LDA) were estimated to compare dementia vs. cognitively normal, MCI vs. cognitively normal, and MCI vs. dementia, using ten individual measures and six cognitive domains. We used a leave-one-out cross-validation procedure to evaluate the predictive capacity of LDA models. RESULTS: Discriminant functions using individual measures and domains distinguished correctly 100% of dementia and cognitively normal groups showing a memory and executive function profile. The predictive group membership for MCI versus cognitively normal varied between 82 and 85%, with a cognitive profile associated with attention-executive function followed by memory. Group separation between MCI and dementia was between 80 and 87%, characterized by orientation, memory, and visuospatial abilities. CONCLUSIONS: The Mex-Cog cognitive battery is useful for identifying cognitive impairment in older adults.

A task force for diagnosis and treatment of people with Alzheimer's disease in Latin America.

Alzheimer's disease (AD) represents a substantial burden to patients, their caregivers, health systems, and society in Latin America and the Caribbean (LAC). This impact is exacerbated by limited access to diagnosis, specialized care, and therapies for AD within and among nations. The region has varied geographic, ethnic, cultural, and economic conditions, which create unique challenges to AD diagnosis and management. To address these issues, the Americas Health Foundation convened a panel of eight neurologists, geriatricians, and psychiatrists from Argentina, Brazil, Colombia, Ecuador, Guatemala, Mexico, and Peru who are experts in AD for a three-day virtual meeting to discuss best practices for AD diagnosis and treatment in LAC and create a manuscript offering recommendations to address identified barriers. In LAC, several barriers hamper diagnosing and treating people with dementia. These barriers include access to healthcare, fragmented healthcare systems, limited research funding, unstandardized diagnosis and treatment, genetic heterogeneity, and varying social determinants of health. Additional training for physicians and other healthcare workers at the primary care level, region-specific or adequately adapted cognitive tests, increased public healthcare insurance coverage of testing and treatment, and dedicated search strategies to detect populations with gene variants associated with AD are among the recommendations to improve the landscape of AD.

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.

The Gut Microbiota-Brain Axis during Aging, Mild Cognitive Impairment and Dementia: Role of Tau Protein, ß-Amyloid and LPS in Serum and Curli Protein in Stool.

Currently, there is an increasing number of people with mild cognitive (MCI) impairment and dementia (D). In the present work we studied the role of tau protein, ß-amyloid, LPS (lipopolysaccharide), and curli protein of elderly adults with MCI or D and the contribution of gut microbiota. Four groups were studied: young subjects, healthy adults older than 60 years (A), elderly adults with MCI (MCI), and elderly adults with dementia (D). A preclinical study was conducted in old male Wistar rats to evaluate the impact of gut microbiota on curli protein abundance in feces and brain. The results showed that with increasing age, tau protein, ß-amyloid, and LPS significantly increased in serum during MCI and D, and this was associated with an increase in the abundance of E. coli that synthesize the amyloid protein curli, that may promote the aggregation of amyloid proteins. Rats showed a clear increase in the abundance of curli protein in the brain during aging. Thus, cognitive impairment and dementia are in part due to an alteration in the gut microbiota-brain axis via increase in curli protein and LPS leading to an increase in tau and ß-amyloid protein.

Asociación entre los niveles de vitamina B12 y el deterioro cognitivo en personas mayores / Association between vitamin B12 levels and cognitive impairment in older adults

Resumen 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.

Abstract 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.

Association of loneliness, social isolation, and daily cognitive function in Mexican older adults living in community during the first wave of COVID-19 pandemic / Asociación del aislamiento social, soledad y la función cognitiva cotidiana en adultos mayores mexicanos de la comunidad durante la primera ola del COVID-19

Abstract Introduction Loneliness and social isolation are known risk factors for cognitive decline; their effect in older adults (OA) after COVID-19 lockdown is emerging. Objective To establish an association between loneliness and social isolation, with daily cognitive function in Mexican OA during the first wave of the COVID-19 pandemic. Method Cross-sectional study, derived from the cohort "The impact of COVID 19 on well-being, cognition, and discrimination among older adults in the United States and Latin America", which included 308 OA recruited between March-August 2020 whose daily cognitive function were determined with the Everyday Cognition Scale (E-Cog) as dichotomized score (cut point: 1.31 for normal cognition). Loneliness and social isolation were binomial variables. Results The mean age was 65.4 ± 7.9 years, 75.7% were women. The mean continuous E-Cog score was 57.4 (SD = ± 19.1), 49.1% had a score < 1.31 (normal cognition), while 50.9% had a higher score (cognitive impairment). Eighty four percent of participants reported loneliness, 79.9% reported social isolation. Multivariate regression model showed a negative and statistically significant association between social isolation and loneliness and E-Cog, adjusted by age, sex and education level (β = -.046, 95% CI = [-.8, -.013], p = .007; β = -.16, 95% CI = [-.08, -.018], p = .003), and a positive association with subjective memory complaint (β = .81, 95% CI = [-.16, -.11], p = < .001). Discussion and conclusion These data suggest the need for increased vigilance of those who have loneliness and social isolation due to its potential deleterious effect on cognitive function.

Resumen Introducción La soledad y el aislamiento social son factores de riesgo conocidos para el deterioro cognitivo; su efecto en las personas mayores (PM) después del confinamiento por COVID-19 está emergiendo. Objetivo Establecer una asociación entre la soledad y el aislamiento social, con la función cognitiva diaria en PM mexicanas durante la primera ola de la pandemia por COVID-19. Método Estudio transversal derivado de la cohorte "The impact of COVID 19 on well-being, cognition, and discrimination among older adults in the United States and Latin America", incluyó 308 AM reclutados de marzo-agosto 2020, la función cognitiva diaria fue evaluada con Everyday Cognition Scale (E-Cog) con un punto de corte 1.31 (cognición normal); la soledad y el aislamiento social fueron variables binomiales. Resultados La media de edad fue 65.4 ± 7.9 años, 75.7% mujeres. E-Cog promedio fue 57.4 (DE = ± 19.1), 49.1 % tenía una puntuación < 1.31 (cognición normal), 50.9% > 1.31 (deterioro cognitivo). Ochenta y cuatro por ciento de los participantes reportaron soledad, 79.9% aislamiento social. El modelo de regresión multivariado mostró una asociación negativa y estadísticamente significativa entre aislamiento social y soledad con E-Cog (β = -.046, IC 95% = [-.8, -.013], p = .007; β = -.16, IC 95% = [-.08, -.018], p = .003), y una asociación positiva con queja de memoria subjetiva (β = .81, IC 95% = [-.16, -.11], p = < .001) ajustado a edad, sexo y escolaridad. Discusión y conclusión Estos datos sugieren la necesidad de una mayor vigilancia de quienes presentan soledad y aislamiento social debido a su potencial efecto deletéreo sobre la función cognitiva.

Who judges medical practice?

Lawsuits due to patient perception of inappropriate medical actions are a growing reality in medical practice, which entails widespread concern in the medical community. Lawsuits often entail additional circumstances beyond the primary concern of preventing or sanctioning acts of medical negligence. CETREMI proposes various recommendations aimed at legal and medical professionals to improve this circumstance and avoid harming the doctor-patient relationship.

Las demandas judiciales por la percepción del paciente de una actuación médica inadecuada son una realidad creciente en la práctica médica, la cual entraña una preocupación extendida en el gremio médico. Las demandas judiciales frecuentemente conllevan circunstancias adicionales a la primaria preocupación de prevenir o sancionar actos de negligencia médica. CETREMI emite algunas recomendaciones a los profesionales jurídicos y médicos para mejorar esta situación y evitar daños en la relación médico-paciente.

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.

Prevalence and Biological Correlates of Oropharyngeal Dysphagia in Outpatients of a Geriatric Evaluation Clinic: A Brief Report.

BACKGROUND: Oropharyngeal dysphagia (OD) is a relevant disease among older adults and is associated with serious adverse health-related outcomes, such as malnutrition, sarcopenia, or frailty. Increasing its recognition and the related mechanisms will allow us to its prevention and treatment at different levels of care. OBJECTIVES: This study aimed to determine the prevalence and biological correlates of OD in outpatient older adults. METHOD: This is a cross-sectional study including 100 adults aged 60 or older from a geriatric clinic of a tertiary hospital in Mexico City. Health variables and geriatric syndromes were recorded. The Eating Assessment Tool-10 detection test and the volume-viscosity swallowing test were used to diagnose OD. Logistic regression models were performed to identify the factors associated with OD. RESULTS: Mean age was 81.2 (±7.5) years and 21% had OD. The presence of xerostomia (p = 0.05) and a worst nutritional status (p = 0.035) were obtained. CONCLUSIONS: The prevalence of OD among older adults was high. Inadequate nutrition status and the presence of xerostomia are more likely to be present with this swallowing disorder.

Use of Fast Gamma Magnetic Stimulation Over the Left Prefrontal Dorsolateral Cortex for the Treatment of MCI and Mild Alzheimer's Disease: A Double-Blind, Randomized, Sham-Controlled, Pilot Study.

Background: Alzheimer's disease (AD) animal models have shown a reduced gamma power in several brain areas, and induction of these oscillations by non-invasive methods has been shown to modify several pathogenic mechanisms of AD. In humans, the application of low-intensity magnetic fields has shown to be able to produce neural entrainment at the magnetic pulse frequency, making it useful to induce gamma frequencies. Objective: The aim of this study was to assess if the application of fast gamma magnetic stimulation (FGMS) over the left prefrontal dorsolateral cortex would be a safe and well-tolerated intervention that could potentially improve cognitive scores in subjects with mild cognitive impairment and mild AD. Methods: In these randomized, double-blind, sham-controlled study, participants were assigned to either receive daily sessions two times a day of active or sham FGMS for 6 months. Afterward, measurements of adverse effects, cognition, functionality, and depression were taken. Results: Thirty-four patients, 17 in each group, were analyzed for the primary outcome. FGMS was adequately tolerated by most of the subjects. Only four patients from the active FGMS group (23.52%) and one patient from the sham FGMS group (5.88%) presented any kind of adverse effects, showing no significant difference between groups. Nevertheless, FGMS did not significantly change cognitive, functionality, or depressive evaluations. Conclusion: FGMS over the left prefrontal dorsolateral cortex applied twice a day for 6 months resulted to be a viable intervention that can be applied safely directly from home without supervision of a healthcare provider. However, no statistically significant changes in cognitive, functionality, or depression scores compared to sham stimulation were observed. Clinical Trial Registration:www.ClinicalTrials.gov, Identifier: NCT03983655, URL: https://clinicaltrials.gov/ct2/show/NCT03983655.

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.