SDNN24 Estimation from Semi-Continuous HR Measures.

The standard deviation of the interval between QRS complexes recorded over 24 h (SDNN24) is an important metric of cardiovascular health. Wrist-worn fitness wearable devices record heart beats 24/7 having a complete overview of users' heart status. Due to motion artefacts affecting QRS complexes recording, and the different nature of the heart rate sensor used on wearable devices compared to ECG, traditionally used to compute SDNN24, the estimation of this important Heart Rate Variability (HRV) metric has never been performed from wearable data. We propose an innovative approach to estimate SDNN24 only exploiting the Heart Rate (HR) that is normally available on wearable fitness trackers and less affected by data noise. The standard deviation of inter-beats intervals (SDNN24) and the standard deviation of the Average inter-beats intervals (ANN) derived from the HR (obtained in a time window with defined duration, i.e., 1, 5, 10, 30 and 60 min), i.e., ANN=60HR (SDANNHR24), were calculated over 24 h. Power spectrum analysis using the Lomb-Scargle Peridogram was performed to assess frequency domain HRV parameters (Ultra Low Frequency, Very Low Frequency, Low Frequency, and High Frequency). Due to the fact that SDNN24 reflects the total power of the power of the HRV spectrum, the values estimated from HR measures (SDANNHR24) underestimate the real values because of the high frequencies that are missing. Subjects with low and high cardiovascular risk show different power spectra. In particular, differences are detected in Ultra Low and Very Low frequencies, while similar results are shown in Low and High frequencies. For this reason, we found that HR measures contain enough information to discriminate cardiovascular risk. Semi-continuous measures of HR throughout 24 h, as measured by most wrist-worn fitness wearable devices, should be sufficient to estimate SDNN24 and cardiovascular risk.

[History of the Department of Neurology at the University of Buenos Aires (1887-2007)]. / Historia de la Cátedra de Neurología de la Universidad de Buenos Aires (1887-2007).

In 1887, only five years after Jean-Martin Charcot was awarded the Head of Neurology at "La Salpetrière" in Paris, José María Ramos Mejía became the first professor of Neurology in South America, at the School of Medicine of the University of Buenos Aires. Ramos Mejía convoked three assistants, the neuropathologist Christofredo Jakob, the clinician José A. Esteves and José Ingenieros. Hence it followed that Neurology in Argentina took a stand based on a clinical neurology-neuropathology approach (1941-1987) followed by a clinical-semiological attitude, finally inserting itself within the modern times (1987-present) by creating subspecialties. Throughout its history, Argentina has made remarkable contributions to Neurology, such as the diagnosis and pathogenesis of the nervous system involvement occurring in some regional endemic disorders -for instance, Chagas' disease-, the clinical approach to the diagnosis of dementias, and the pathogenesis of extrapyramidal illnesses and other primary degenerative diseases of the central nervous system, mainly amyotrophic lateral sclerosis. On the other hand, in recent years globalization allowed neurologists to participate in international cooperative projects, favoring a swifter development in the practice of this discipline.

Clinical and economic characteristics associated with direct costs of Alzheimer's, frontotemporal and vascular dementia in Argentina.

BACKGROUND: The economic cost of dementia is high and can be predicted by cognitive and neuropsychiatric profiles. The differential costs of the various subtypes of dementia are unknown in Argentina, and this study therefore aimed to compare these costs. METHODS: Patients with a diagnosis of dementia of Alzheimer-type (DAT), frontotemporal dementia (FTD) and vascular dementia (VaD), and their primary caregivers, were evaluated between 2002 and 2008. RESULTS: 104 patients with dementia (DAT = 44, FTD = 34, VaD = 26) were screened and matched by age and educational level with 29 healthy subjects. Demographic variables showed no significant differences among dementia patients. The annual direct costs were US$4625 for DAT, US$4924 for FTD, and US$5112 for VaD (p > 0.05 between groups). In the post hoc analysis VaD showed higher hospitalization costs than DAT (p < 0.001). VaD exhibited lower medication costs than FTD (p < 0.001). DAT exhibited higher anti-dementia drug costs; FTD had higher psychotropic costs. In the multivariate analysis, depression, activities of daily living, and caregiver burden were correlated with direct costs (r2 = 0.76). CONCLUSIONS: The different dementia types have different costs. Overall, costs increased with the presence of behavioral symptoms, depression and functional impairment of activities of daily living.

[Use and abuse of drugs in cognitive impairment patients]. / Usos y abusos de fármacos en pacientes con deterioro cognitivo.

INTRODUCTION: Irrational use of drugs for the treatment of cognitive impairment can increase health costs in developing countries. OBJECTIVE: to analyze the pattern of drug prescription related to the treatment of patients with dementia and to compare them with the income of patients. PATIENTS: 313 community-based outpatients that seeked medical advice for memory problems, in the Memory Center of Zubizarreta General Hospital (Buenos Aires, Argentina), were prospectively assessed during a period of a year. RESULTS: Patients' mean income was 502.81 "Pesos Argentinos" which is equivalent to US$152 per month (2007). Fourty one point fifty five percent (41.55%) of the patients had dementia, 15.65% psychiatric diseases, 15.01% mild cognitive impairment and 27.79% were normal. Patients received an average of 2.84 drugs/day, 20% of the patients took at least one drug for cognitive impairment (9.85% memantine, 6.38% donepezil and 4% nootropics, cerebral vasodilators or antioxidants), and 39.3% received psychotropic medication (28.11% benzodiazepines and 9.26 % atypical antipsychotics). Twelve point seventy six percent (12.76%) of the patients with mild cognitive impairment were treated with antidementials, 5.74% of normal subjects received antidementials. 4% of patients were exclusively treated with free samples. CONCLUSION: In our sample irrational degree of using antidemential drugs and psychotropic agents was found.

A computationally efficient algorithm to obtain an accurate and interpretable model of the effect of circadian rhythm on resting heart rate.

OBJECTIVE: Wrist-worn wearable devices equipped with heart rate (HR) sensors have become increasingly popular. The ability to correctly interpret the collected data is fundamental to analyse user's well-being and perform early detection of abnormal physiological data. Circadian rhythm is a strong factor of variability in HR, yet few models attempt to accurately model its effect on HR. APPROACH: In this paper we present a mathematical derivation of the single-component cosinor model with multiple components that fits user data to a predetermined arbitrary function (the expected shape of the circadian effect on resting HR (RHR)), thus permitting us to predict the user's circadian rhythm component (i.e. MESOR, Acrophase and Amplitude) with a high accuracy. MAIN RESULTS: We show that our model improves the accuracy of HR prediction compared to the single component cosinor model (10% lower RMSE), while retaining the readability of the fitted model of the single component cosinor. We also show that the model parameters can be used to detect sleep disruption in a qualitative experiment. The model is computationally cheap, depending linearly on the size of the data. The computation of the model does not need the full dataset, but only two surrogates, where the data is accumulated. This implies that the model can be implemented in a streaming approach, with important consequences for security and privacy of the data, that never leaves the user devices. SIGNIFICANCE: The multiple component model provided in this paper can be used to approximate a user's RHR with higher accuracy than single component model, providing traditional parameters easy to interpret (i.e. the same produced by the single component cosinor model). The model we developed goes beyond fitting circadian activity on RHR, and it can be used to fit arbitrary periodic real valued time series, vectorial data, or complex data.

Profiling the propagation of error from PPG to HRV features in a wearable physiological-monitoring device.

Wearable physiological monitors are becoming increasingly commonplace in the consumer domain, but in literature there exists no substantive studies of their performance when measuring the physiology of ambulatory patients. In this Letter, the authors investigate the reliability of the heart-rate (HR) sensor in an exemplar 'wearable' wrist-worn monitoring system (the Microsoft Band 2); their experiments quantify the propagation of error from (i) the photoplethysmogram (PPG) acquired by pulse oximetry, to (ii) estimation of HR, and (iii) subsequent calculation of HR variability (HRV) features. Their experiments confirm that motion artefacts account for the majority of this error, and show that the unreliable portions of HR data can be removed, using the accelerometer sensor from the wearable device. The experiments further show that acquired signals contain noise with substantial energy in the high-frequency band, and that this contributes to subsequent variability in standard HRV features often used in clinical practice. The authors finally show that the conventional use of long-duration windows of data is not needed to perform accurate estimation of time-domain HRV features.

Inverse association between yerba mate consumption and idiopathic Parkinson's disease. A case-control study.

Yerba mate tea is a very common beverage in some countries of South America. We conducted a case-control study on an individual basis using hospital records to investigate the association between Parkinson's disease (PD) and yerba mate intake. A case was defined as an age of ≥ 40 years with ≥ 1 year of PD. Each case was individually matched by two controls. Exposure was measured by yerba mate consumption, coffee, tea, and alcohol intake and smoking status. The sample consisted of 223 PD patients (mean age 68 years and mean disease duration 7.3 years) and 406 controls. There was an inverse association between yerba mate "bombilla" consumption and PD (OR 0.64, 95% CI: 0.54-0.76, p=0.00001). A multivariate analysis with a logistic regression adjusted by sex, alcohol intake and smoking provided the following results: yerba mate (OR 0.63, 95% CI: 0.53-0.76), tea (OR 0.60, 95% CI: 0.42-0.86), coffee (OR 0.51, 95% CI: 0.35-0.73). We found an inverse association between yerba mate consumption and PD. These results led us to hypothesize that yerba mate may have a potential protective role in the development of PD.

MM1+2C sporadic Creutzfeldt-Jakob disease presenting as rapidly progressive nonfluent aphasia.

We report a 77-year-old man, presenting with progressive aphasia as an initial symptom, who developed severe dementia over the course of 20 months. Frontal cortex PrPSc western blot was type 2 and codon 129 was MM; brain neuropathology showed cortical vacuoles with perivacuolar PrP immunostaining characteristic of MM2C. Cerebellum showed focal coarse, patchy staining in different sections of the molecular layer, diffuse fine punctuate and coarse PrP immunopositive deposits in the granule cell layer, and focal synaptic immunostaining in the molecular layer, suggestive of MM1+2C by histotyping. This clinical presentation has not yet been described in an MM1+2C subtype by histotyping.

Diagnostic accuracy of the Phototest for cognitive impairment and dementia in Argentina.

Phototest is a simple, easy and very brief test with theoretical advantages over available dementia screening tests in Spain. The objective of this study was to estimate the diagnostic accuracy of the Phototest for cognitive impairment and dementia and to compare it with that of the MMSE and the Clock Drawing Test (CDT) in an Argentine population. A phase II cross-sectional study of diagnostic tests evaluation was performed in a sample of 30 controls, 61 with amnestic mild cognitive impairment (a-MCI), and 56 with mild Alzheimer type dementia (DAT). The diagnostic accuracy (DA) was assessed in relation to the clinical diagnosis by calculating the area under the ROC curve (UAC), Sensitivity (Sn), and Specificity (Sp).The DA of the Phototest for a-MCI and DAT (0.93 and 0.97 [UAC]) was higher than that of the MMSE and the CDT. The cut-off points of 27/28 for DAT (Sn = 89.29 [78.1-96.0], Sp = 96.67 [82.8-99.9]) and 30/31 for a-MCI (Sn = 85.25 [73.8-93.0], Sp = 90.00 [73.5-97.9]) maximized the sum of Sn and Sp. Phototest correlates significantly with MMSE and CDT. The Phototest is an efficient instrument for the detection of mild dementia or MCI, with good accuracy and good correlation with tests measuring overall cognitive impairment.

A population-based study of cognitive impairment in socially vulnerable adults in Argentina. The Matanza Riachuelo study preliminary results.

Population aging has taken place intensively worldwide, even in developing countries. These countries have population groups with low resources and basic unmet needs that are frequently omitted from epidemiological studies. OBJECTIVE: The purpose of this study was to determine the prevalence of cognitive impairment (CI) and dementia in an economic and socially vulnerable population from Argentina. METHODS: A door-to-door observational population-based survey among adults over 60 years of cognitive impairment and dementia in the social vulnerable area of the Matanza Riachuelo Basin, in the suburban area of Buenos Aires, Argentina was conducted. Trained psychologists interviewed subjects and a proxy informant. A standardized protocol including a socio-demographic questionnaire, the Mini-Mental State Examination, the Geriatric Depression Scale and a functional inventory for IADL and ADL was administered. Diagnoses were divided into three general categories: normal cognitive function, cognitive impairment-no dementia (CIND) and dementia. RESULTS AND CONCLUSIONS: A total of 2437 elderly persons were assessed, of which 73.6% fulfilled inclusion criteria. The prevalence of CI among those over 60 was 26.4% (18.1% CIND and 8.3% dementia) with higher prevalence of dementia in younger individuals than rates reported in developed counties, probably due to low control of vascular risk factors. This information can help inform health public decisions in the generation of programs and plans for the prevention, diagnosis and treatment of cognitive impairment in this type of socially vulnerable population.

O envelhecimento da população idosa tem aumentado mundialmente, mesmo em países em desenvolvimento. Estes países têm grupos populacionais de poucos recursos, com necessidades básicas não satisfatórias, frequentemente omitidas nos estudos epidemiológicos. OBJETIVO: O propósito deste estudo foi determinar a prevalência de comprometimento cognitivo (CC) e demência em uma população socioeconomicamente vulnerável na Argentina. MÉTODOS: Foi realizada pesquisa observacional de base populacional porta-a-porta entre adultos acima de 60 anos numa área de vulnerabilidade social em Matanza Riachuelo, no subúrbio de Buenos Aires, Argentina. Psicólogos treinados entrevistaram o sujeito e um acompanhante. Um protocolo estandardizado que incluiu um questionário sociodemográfico, o MEEM, a escala de depressão geriátrica e um inventário funcional para ABVD e AIVD foram administrados. Os diagnósticos foram divididos em três categorias: função cognitiva normal, comprometimento cognitivo sem demência (CCSD) e demência. RESULTADOS: Foram avaliados um total de 2437 de idosos, dos quais 73,6% preencheram os critérios de inclusão. A prevalência de CC entre aqueles acima de 60 anos foi de 26,4% (18,1% CCSD e 8,3% de demência) com maiores prevalência de demência em indivíduos mais jovens do que os reportados em países desenvolvidos, provavelmente devido a controle inadequado dos fatores de risco vasculares. CONCLUSÃO: Esta informação pode contribuir para tomada de decisões em saúde pública para geração de programas e planos que apontem para a prevenção, diagnóstico e tratamento de CC neste tipo de população em vulnerabilidade social.

Familial dementia with frontotemporal features associated with M146V presenilin-1 mutation.

Most of the mutations in the presenilin-1 gene (PS-1) are associated with familial Alzheimer's disease (AD). However, certain examples can be associated with frontotemporal dementia (FTD). We performed a clinical evaluation of individuals belonging to a family with the FTD phenotype, and additional molecular studies and neuropathological assessment of the proband. The PS-1 M146V mutation was found in the 50-year-old subject (the proband) with family history of early-onset FTD. Neuropathological examination showed abundant amyloid plaques, widespread neurofibrillary pathology, Pick bodies in the hippocampus and cortex, cortical globose tangles and ubiquitin-positive nuclear inclusions in white matter oligodendrocytes. We report a kindred with clinical features of FTD, whose proband bore the PS-1 M146V mutation and showed diffuse Alzheimer's type pathology and Pick bodies on post-mortem neuropathological examination. As with other mutations within the same codon, this substitution may predispose to both diseases by affecting APP and/or tau processing.

A population-based study of cognitive impairment in socially vulnerable adults in Argentina. The Matanza Riachuelo Study: preliminary results / Estudo de comprometimento cognitivo de base populacional em adultos socialmente vulneráveis. estudo Matanza Riachuelo

Population aging has taken place intensively worldwide, even in developing countries. These countries have population groups with low resources and basic unmet needs that are frequently omitted from epidemiological studies. Objective: The purpose of this study was to determine the prevalence of cognitive impairment (CI) and dementia in aneconomic and socially vulnerable population from Argentina. Methods: A door-to-door observational population-based survey among adults over 60 years of cognitive impairment and dementia in the social vulnerable area of the Matanza Riachuelo Basin, in the suburban area of Buenos Aires, Argentina was conducted. Trained psychologists interviewed subjects and a proxy informant. A standardized protocol including a socio-demographic questionnaire, the Mini-Mental State Examination, the Geriatric Depression Scale and a functional inventory for IADL and ADL was administered. Diagnoses were divided into three general categories: normal cognitive function, cognitive impairment-no dementia (CIND) and dementia. Results and Conclusions: A total of 2437 elderly persons were assessed, of which 73.6% fulfilled inclusion criteria. The prevalence of CI among those over 60 was 26.4% (18.1% CIND and 8.3% dementia) with higher prevalence of dementia in younger individuals than rates reported in developed counties, probably due to low control of vascular risk factors. This information can help inform health public decisions in the generation of programs and plans for the prevention, diagnosis and treatment of cognitive impairment in this type of socially vulnerable population.

O envelhecimento da população idosa tem aumentado mundialmente, mesmo em países em desenvolvimento. Estes países têm grupos populacionais de poucos recursos, com necessidades básicas não satisfatórias, frequentemente omitidas nos estudos epidemiológicos. Objetivo: O propósito deste estudo foi determinar a prevalência de comprometimento cognitivo (CC) e demência em uma população socioeconomicamente vulnerável na Argentina. Métodos: Foi realizada pesquisa observacional de base populacional porta-a-porta entre adultos acima de 60 anos numa área de vulnerabilidade social em Matanza Riachuelo, no subúrbio de Buenos Aires, Argentina. Psicólogos treinados entrevistaram o sujeito e um acompanhante. Um protocolo estandardizado que incluiu um questionário sociodemográfico, o MEEM, a escala de depressão geriátrica e um inventário funcional para ABVD e AIVD foram administrados. Os diagnósticos foram divididos em três categorias: função cognitiva normal, comprometimento cognitivo sem demência (CCSD) e demência. Resultados: Foram avaliados um total de 2437 de idosos, dos quais 73,6% preencheram os critérios de inclusão. A prevalência de CC entre aqueles acima de 60 anos foi de 26,4% (18,1% CCSD e 8,3% de demência) com maiores prevalência de demência em indivíduos mais jovens do que os reportados em países desenvolvidos, provavelmente devido a controle inadequado dos fatores de risco vasculares. Conclusão: Esta informação pode contribuir para tomada de decisões em saúde pública para geração de programas e planos que apontem para a prevenção, diagnóstico e tratamento de CC neste tipo de população em vulnerabilidade social.

Síntomas neuropsiquiátricos en la afasia progresiva primaria / No disponible

No disponible