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The accuracy of the Clock Drawing Test compared to that of standard screening tests for Alzheimer`s disease: results from a study of Brazilian elderly with heterogeneous educational backgrounds

APRAHAMIAN, Ivan; MARTINELLI, Jose Eduardo; NERI, Anita Liberalesso; YASSUDA, Monica Sanches
Fonte: CAMBRIDGE UNIV PRESS Publicador: CAMBRIDGE UNIV PRESS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
27.33%
Background: Although the Clock Drawing Test (CDT) is the second most used test in the world for the screening of dementia, there is still debate over its sensitivity specificity, application and interpretation in dementia diagnosis. This study has three main aims: to evaluate the sensitivity and specificity of the CDT in a sample composed of older adults with Alzheimer`s disease (AD) and normal controls; to compare CDT accuracy to the that of the Mini-mental State Examination (MMSE) and the Cambridge Cognitive Examination (CAMCOG), and to test whether the association of the MMSE with the CDT leads to higher or comparable accuracy as that reported for the CAMCOG. Methods: Cross-sectional assessment was carried out for 121 AD and 99 elderly controls with heterogeneous educational levels from a geriatric outpatient clinic who completed the Cambridge Examination for Mental Disorder of the Elderly (CAMDEX). The CDT was evaluated according to the Shulman, Mendez and Sunderland scales. Results: The CDT showed high sensitivity and specificity. There were significant correlations between the CDT and the MMSE (0.700-0.730; p < 0.001) and between the CDT and the CAMCOG (0.753-0.779; p < 0.001). The combination of the CDT with the MMSE improved sensitivity and specificity (SE = 89.2-90%; SP = 71.7-79.8%). Subgroup analysis indicated that for elderly people with lower education...

Mini-Mental State Examination performance in frail, pre-frail, and non-frail community dwelling older adults in Ermelino Matarazzo, Sao Paulo, Brazil

Monteiro Macuco, Claudia Rodrigues; Batistoni, Samila Sathler Tavares; Lopes, Andrea; Cachioni, Meire; Falcão, Deusivania Vieira da Silva; Neri, Anita Liberalesso; Yassuda, Monica Sanches
Fonte: Cambridge Univ Press; New York Publicador: Cambridge Univ Press; New York
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
27.33%
Background: Frailty in older adults is a multifactorial syndrome defined by low metabolic reserve, less resistance to stressors, and difficulty in maintaining organic homeostasis due to cumulative decline of multiple physiological systems. The relationship between frailty and cognition remains unclear and studies about Mini-Mental State Examination (MMSE) performance and frailty are scarce. The objective was to examine the association between frailty and cognitive functioning as assessed by the MMSE and its subdomains. Methods: A cross-sectional population-based study (FIBRA) was carried out in Ermelino Matarazzo, a poor subdistrict of the city of Sao Paulo, Brazil. Participants were 384 community dwelling older adults, 65 years and older who completed the MMSE and a protocol to assess frailty criteria as described in the Cardiovascular Health Study (CHS). Results: Frail older adults had significantly worse performance on the MMSE (p < 0.001 for total score). Linear regression analyses showed that the MMSE total score was influenced by age (p < 0.001), education (p < 0.001), family income (p < 0.001), and frailty status (p < 0.036). Being frail was associated more significantly with worse scores in Time Orientation (p < 0.004) and Immediate Memory (p < 0.001). Conclusions: Our data suggest that being frail is associated with worse cognitive performance...

The accuracy of the Clock Drawing Test compared to that of standard screening tests for Alzheimer`s disease: results from a study of Brazilian elderly with heterogeneous educational backgrounds

APRAHAMIAN, Ivan; MARTINELLI, Jose Eduardo; NERI, Anita Liberalesso; YASSUDA, Monica Sanches
Fonte: CAMBRIDGE UNIV PRESS Publicador: CAMBRIDGE UNIV PRESS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
27.33%
Background: Although the Clock Drawing Test (CDT) is the second most used test in the world for the screening of dementia, there is still debate over its sensitivity specificity, application and interpretation in dementia diagnosis. This study has three main aims: to evaluate the sensitivity and specificity of the CDT in a sample composed of older adults with Alzheimer`s disease (AD) and normal controls; to compare CDT accuracy to the that of the Mini-mental State Examination (MMSE) and the Cambridge Cognitive Examination (CAMCOG), and to test whether the association of the MMSE with the CDT leads to higher or comparable accuracy as that reported for the CAMCOG. Methods: Cross-sectional assessment was carried out for 121 AD and 99 elderly controls with heterogeneous educational levels from a geriatric outpatient clinic who completed the Cambridge Examination for Mental Disorder of the Elderly (CAMDEX). The CDT was evaluated according to the Shulman, Mendez and Sunderland scales. Results: The CDT showed high sensitivity and specificity. There were significant correlations between the CDT and the MMSE (0.700-0.730; p < 0.001) and between the CDT and the CAMCOG (0.753-0.779; p < 0.001). The combination of the CDT with the MMSE improved sensitivity and specificity (SE = 89.2-90%; SP = 71.7-79.8%). Subgroup analysis indicated that for elderly people with lower education...

Mini-Mental State Examination performance in frail, pre-frail, and non-frail community dwelling older adults in Ermelino Matarazzo, Sao Paulo, Brazil

Monteiro Macuco, Claudia Rodrigues; Tavares Batistoni, Samila Satler; Lopes, Andrea; Cachioni, Meire; da Silva Falcao, Deusivania Vieira; Neri, Anita Liberalesso; Yassuda, Monica Sanches
Fonte: Cambridge Univ Press; New York Publicador: Cambridge Univ Press; New York
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
27.33%
Background: Frailty in older adults is a multifactorial syndrome defined by low metabolic reserve, less resistance to stressors, and difficulty in maintaining organic homeostasis due to cumulative decline of multiple physiological systems. The relationship between frailty and cognition remains unclear and studies about Mini-Mental State Examination (MMSE) performance and frailty are scarce. The objective was to examine the association between frailty and cognitive functioning as assessed by the MMSE and its subdomains. Methods: A cross-sectional population-based study (FIBRA) was carried out in Ermelino Matarazzo, a poor subdistrict of the city of Sao Paulo, Brazil. Participants were 384 community dwelling older adults, 65 years and older who completed the MMSE and a protocol to assess frailty criteria as described in the Cardiovascular Health Study (CHS). Results: Frail older adults had significantly worse performance on the MMSE (p < 0.001 for total score). Linear regression analyses showed that the MMSE total score was influenced by age (p < 0.001), education (p < 0.001), family income (p < 0.001), and frailty status (p < 0.036). Being frail was associated more significantly with worse scores in Time Orientation (p < 0.004) and Immediate Memory (p < 0.001). Conclusions: Our data suggest that being frail is associated with worse cognitive performance...

Mini exame dos estado mental e o diagnóstico de demência no Brasil

ALMEIDA,OSVALDO P.
Fonte: Academia Brasileira de Neurologia - ABNEURO Publicador: Academia Brasileira de Neurologia - ABNEURO
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/1998 PT
Relevância na Pesquisa
27.46%
O diagnóstico de demência tem como base a presença de declínio da memória e de outras funções cognitivas. Diversos instrumentos foram desenvolvidos durante os últimos anos com o objetivo de auxiliar na investigação de possíveis déficits cognitivos em indivíduos de risco, como é o caso dos idosos. O Mini-Exame do Estado Mental (MMSE) é a escala de avaliação cognitiva mais amplamente utilizada com essa finalidade. Apesar disso, o MMSE ainda não foi adequadamente validado para o diagnóstico específico de demência no Brasil. Este estudo foi desenhado com os seguintes objetivos: (1) investigar o melhor ponto de corte do MMSE para o diagnóstico de demência em uma amostra de idosos atendidos em um ambulatório de saúde mental; e (2) estudar o impacto da idade e escolaridade sobre o escore total final da escala. Duzentos e onze pacientes com mais de 60 anos de idade que buscaram tratamento junto à Unidade de Idosos do ambulatório de saúde mental da Santa Casa de São Paulo entre fevereiro de 1997 e fevereiro de 1998 foram incluídos no estudo. Eles foram avaliados de forma sistemática com o SRQ-20, MMSE e entrevista clínica para realização do diagnóstico clínico de acordo com a CID-10. Setenta (33,2%) pacientes receberam o diagnóstico de demência. Os escores do MMSE foram comparados no grupo de pacientes sem e com demência. O ponto de corte 23/24 (caso/não caso) revelou índices de sensibilidade e especificidade de 84...

MMSE Scores Decline at a Greater Rate in Frontotemporal Degeneration Than in AD

Chow, Tiffany W.; Hynan, Linda S.; Lipton, Anne M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.33%
The clinical diagnostic criteria for frontotemporal degeneration (FTD) include relative preservation of memory and visuospatial function, in contradistinction to characteristics of Alzheimer’s disease (AD). The Mini-Mental State Examination (MMSE) contains items to assess these areas of cognition. In a retrospective case-control study of participants at two institutionally-based AD centers, we determined whether total MMSE and MMSE subscores would reflect the disease progression projected by the clinical criteria of FTD vs. AD. Participants were 44 subjects with FTD (7 pathologically confirmed) and 45 with pathologically confirmed AD. Each subject had at least two MMSEs with minimum inter-test intervals of 9 months. We compared annualized rates of change for total MMSE scores and cognitive domain subscores over time and between groups by two independent samples t-tests and proportion tests. The total MMSE score (p = 0.03) and language subscore (p = 0.02) showed a greater rate of decline for the FTD group than the AD group, although the constructional praxis item declined less rapidly in the FTD group (p = 0.018). Changes in MMSE subscores paralleled the clinical diagnostic criteria for FTD. The more rapid progression on the language subscore was observed in both language and behavioral variants of FTD.

How predictive is the MMSE for cognitive performance after stroke?

Bour, Ariane; Rasquin, Sascha; Boreas, Anita; Limburg, Martien; Verhey, Frans
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.33%
Cognitive deficits are commonly observed in stroke patients. Neuropsychological testing is time-consuming and not easy to administer after hospital discharge. Standardised screening measures are desirable. The Mini-Mental State Examination (MMSE) is the test most widely applied to screen for cognitive deficits. Despite its broad use, its predictive characteristics after stroke have not been exhaustively investigated. The aim of this study was to determine whether the MMSE is able to adequately screen for cognitive impairment and dementia after stroke and whether or not the MMSE can predict further deterioration or recovery in cognitive function over time. To this end, we studied 194 first-ever stroke patients without pre-stroke cognitive deterioration who underwent MMSEs and neuropsychological test batteries at 1, 6, 12, and 24 months after stroke. The MMSE score 1 month after stroke predicted cognitive functioning at later follow-up visits. It could not predict deterioration or improvement in cognitive functioning over time. The cut-off score in the screening for 1 cognitive disturbed domain was 27/28 with a sensitivity of 0.72. The cut-off score in the screening for at least 4 impaired domains and dementia were 26/27 and 23/24 with a sensitivity of 0.82 and 0.96...

A Hybrid Multiuser Detector Based on MMSE and AFSA for TDRS System Forward Link

Yin, Zhendong; Jiang, Xu; Wu, Zhilu; Liu, Xiaohui
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.38%
This study mainly focuses on multiuser detection in tracking and data relay satellite (TDRS) system forward link. Minimum mean square error (MMSE) is a low complexity multiuser detection method, but MMSE detector cannot achieve satisfactory bit error ratio and near-far resistance, whereas artificial fish swarm algorithm (AFSA) is expert in optimization and it can realize the global convergence efficiently. Therefore, a hybrid multiuser detector based on MMSE and AFSA (MMSE-AFSA) is proposed in this paper. The result of MMSE and its modified formations are used as the initial values of artificial fishes to accelerate the speed of global convergence and reduce the iteration times for AFSA. The simulation results show that the bit error ratio and near-far resistance performances of the proposed detector are much better, compared with MF, DEC, and MMSE, and are quite close to OMD. Furthermore, the proposed MMSE-AFSA detector also has a large system capacity.

Reduced Complexity Soft MMSE MIMO Detector Architecture

Amiri, Kiarash; Dick, Chris; Rao, Raghu; Cavallaro, Joseph R.
Fonte: Wireless Innovation Forum, Inc. Publicador: Wireless Innovation Forum, Inc.
Tipo: Conference paper
ENG
Relevância na Pesquisa
37.2%
Computing the soft LLR values in MMSE receivers of MIMO systems requires a very large complexity. In this paper, we propose a reduced complexity soft MMSE detector for MIMO systems. We use different complexity reductions techniques and propose an architecture based on the new reduced-complexity method. We also compare the complexity and show more than 2x complexity reduction using this method. We present complexity/performance tradeoffs to demonstrate the efficacy of our techniques. More importantly, these techniques give the receivers the flexibility to choose how accurately they perform the detection based on the available resources.

Low complexity MMSE based interference cancellation for LTE uplink MIMO receiver

Yin, Bei; Cavallaro, Joseph R.
Fonte: Wireless Innovation Forum Publicador: Wireless Innovation Forum
Tipo: Conference paper
ENG
Relevância na Pesquisa
36.95%
In this paper, we propose a novel low complexity minimum mean square error (MMSE) interference cancellation (IC) to minimize the residual inter-symbol and inter-antenna interference in LTE/LTE-Advanced uplink. In the LTE/LTE-Advanced base station, frequency domain equalizers (FDEs) are adopted to achieve good performance. However, in multi-tap channels, the residual interference of FDE still degrades the performance. Conventional IC schemes can minimize this interference, but have high complexity and large feedback latency. These result in low throughput and require a large amount of resource in software defined radio (SDR) implementation. We show that our scheme can bring up to 8 dB gains in different channels, but only adds up to 7.2% complexity to the receiver. Compared to conventional IC, our scheme has fewer multiplications, less data to store, and shorter feedback latency.

Implementation of LS, MMSE and SAGE Channel Estimators for Mobile MIMO-OFDM

Ketonen, Johanna; Juntti, Markku; Ylioinas, Jari; Cavallaro, Joseph R.
Fonte: IEEE Publicador: IEEE
Tipo: Conference paper
ENG
Relevância na Pesquisa
37.1%
The use of decision directed (DD) channel estimation in a multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) downlink receiver is studied in this paper. The 3GPP long term evolution (LTE) based pilot structure is used as a benchmark. The space-alternating generalized expectation-maximization (SAGE) algorithm is used to improve the performance from that of the pilot symbol based least-squares (LS) channel estimator. The DD channel estimation improves the performance with high user velocities, where the pilot symbol density is not sufficient. Minimum mean square error (MMSE) filtering can also be used in estimating the channel in between pilot symbols. The DD channel estimation can be used to reduce the pilot overhead without any performance degradation by transmitting data instead of pilot symbols. The pilot overhead is reduced to a third of the LTE pilot overhead, obtaining a ten percent increase in throughput. The pilot based LS, MMSE and the SAGE channel estimators are implemented and the performance-complexity trade-offs are studied.

Bit error rate performance of MIMO MMSE receivers in correlated rayleigh flat-fading channels

Hong, Li; García-Armada, Ana
Fonte: IEEE Publicador: IEEE
Tipo: info:eu-repo/semantics/acceptedVersion; info:eu-repo/semantics/article Formato: application/pdf; text/plain
Publicado em /01/2011 ENG
Relevância na Pesquisa
36.95%
This paper analyzes the average bit error rate (BER) of multiple-input-multiple-output (MIMO) systems in transmit-correlated Rayleigh flat-fading channels. The receiver scheme is based on the minimum mean square error (MMSE) criterion, and the input may be precoded to optimize the communication. Accurate closed-form formulations for the average BER are derived; This work was supported in part by Project TEC2008-06327-C03-02, Project CSD2008- 00010, and Project CCG08-UC3M/TIC-4069

Different MMSE Score Is Associated with Postoperative Delirium in Young-Old and Old-Old Adults

Wu, Yujie; Shi, Zhongyong; Wang, Meijuan; Zhu, Yingbo; Li, Cheng; Li, Guodong; Marcantonio, Edward R.; Xie, Zhongcong; Shen, Yuan
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
27.41%
Background: Postoperative delirium is one of the most common postoperative complications in geriatric patients. Mini-mental state examination (MMSE) assesses cognitive function in patients and is associated with postoperative delirium. However, whether there is an age-dependent relationship between preoperative MMSE score and postoperative delirium remains unknown. Methods: We therefore set out to investigate the association between preoperative MMSE score and postoperative delirium in young-old (≤80 year-old, 75.46±4.69 years, 27.0% male, n = 63) and old-old (>80 year-old, 84.51±3.46 years, 20.9% male, n = 67) participants, who had repairs of hip fractures under general anesthesia. The Confusion Assessment Method and Memorial Delirium Assessment Scale were administrated before surgery, and on the first, second and fourth days after surgery, to assess the incidence and severity of the delirium, respectively. A receiver operating characteristic curve analysis was used to calculate the optimal cutoff score of MMSE in predicting postoperative delirium. Results: Thirty-four (26.2%) of 130 patients (80.12±6.12 years, 23.8% male) developed postoperative delirium. Preoperative MMSE scores were negatively associated with higher incidences and greater severity of postoperative delirium. The optimal cutoff scores of MMSE associated with postoperative delirium for young-old and old-old participants were 18.4 and 21.4...

Utility of the NeuroTrax Computerized Battery for Cognitive Screening in Parkinson's Disease: Comparison with the MMSE and the MoCA

Hanna-Pladdy, B.; Enslein, A.; Fray, M.; Gajewski, B. J.; Pahwa, R.; Lyons, K. E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/2010 EN
Relevância na Pesquisa
27.28%
To determine the utility of a computerized assessment in Parkinson's disease (PD), we compared the cognitive performance of 50 PD patients on the NeuroTrax computerized battery relative to the mini-mental state examination (MMSE) and the Montreal Cognitive Assessment (MoCA). The results revealed fair agreement between impairment on the NeuroTrax and the MMSE (κ = .291, p = .031) but only slight agreement between the NeuroTrax and the MoCA (κ=.138, p = .054) and between the MoCA and the MMSE (κ = .168, p = .069). The NeuroTrax identified 52% of the sample as average or above, 40% as below average, and 8% as impaired. The MoCA identified 54% of the sample as impaired (28% average or above and 18% below average), while the MMSE identified 66% as average or above (20% below average and 14% impaired). Several stepwise regressions revealed that executive and verbal functions were the best predictors of cognitive functioning on the NeuroTrax, while memory recall, serial sevens, naming, and abstraction were the best predictors on the MoCA. These results suggest that although the NeuroTrax may be useful in identifying executive cognitive deficits in PD, similar to the MMSE the NeuroTrax may lack optimal sensitivity. While the MoCA is sensitive...

Low-Complexity Partitioned-Spreading CDMA System with Multistage MMSE Reception

Shi, Zhenning; Reed, Mark
Fonte: Institute of Electrical and Electronics Engineers (IEEE Inc) Publicador: Institute of Electrical and Electronics Engineers (IEEE Inc)
Tipo: Conference paper
Relevância na Pesquisa
36.95%
In this paper, we propose a low-complexity multistage filter for the partitioned-spreading CDMA (PS-CDMA). The proposed method embodies a MMSE filter that operates on the soft output of interference cancellation. Extrinsic information on the partitioned s

Adaptive and Iterative Multi-Branch MMSE Decision Feedback Detection Algorithms for MIMO Systems

de Lamare, R. C.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 12/08/2013
Relevância na Pesquisa
27.44%
In this work, decision feedback (DF) detection algorithms based on multiple processing branches for multi-input multi-output (MIMO) spatial multiplexing systems are proposed. The proposed detector employs multiple cancellation branches with receive filters that are obtained from a common matrix inverse and achieves a performance close to the maximum likelihood detector (MLD). Constrained minimum mean-squared error (MMSE) receive filters designed with constraints on the shape and magnitude of the feedback filters for the multi-branch MMSE DF (MB-MMSE-DF) receivers are presented. An adaptive implementation of the proposed MB-MMSE-DF detector is developed along with a recursive least squares-type algorithm for estimating the parameters of the receive filters when the channel is time-varying. A soft-output version of the MB-MMSE-DF detector is also proposed as a component of an iterative detection and decoding receiver structure. A computational complexity analysis shows that the MB-MMSE-DF detector does not require a significant additional complexity over the conventional MMSE-DF detector, whereas a diversity analysis discusses the diversity order achieved by the MB-MMSE-DF detector. Simulation results show that the MB-MMSE-DF detector achieves a performance superior to existing suboptimal detectors and close to the MLD...

A Multi-cell MMSE Precoder for Massive MIMO Systems and New Large System Analysis

Li, Xueru; Björnson, Emil; Larsson, Erik G.; Zhou, Shidong; Wang, Jing
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 05/09/2015
Relevância na Pesquisa
27.33%
In this paper, a new multi-cell MMSE precoder is proposed for massive MIMO systems. We consider a multi-cell network where each cell has $K$ users and $B$ orthogonal pilot sequences are available, with $B = \beta K$ and $\beta \ge 1$ being the pilot reuse factor over the network. In comparison with conventional single-cell precoding which only uses the $K$ intra-cell channel estimates, the proposed multi-cell MMSE precoder utilizes all $B$ channel directions that can be estimated locally at a base station, so that the transmission is designed spatially to suppress both parts of the inter-cell and intra-cell interference. To evaluate the performance, a large-scale approximation of the downlink SINR for the proposed multi-cell MMSE precoder is derived and the approximation is tight in the large-system limit. Power control for the pilot and payload, imperfect channel estimation and arbitrary pilot allocation are accounted for in our precoder. Numerical results show that the proposed multi-cell MMSE precoder achieves a significant sum spectral efficiency gain over the classical single-cell MMSE precoder and the gain increases as $K$ or $\beta$ grows. Compared with the recent M-ZF precoder, whose performance degrades drastically for a large $K$...

Enhanced MMSE Channel Estimation Using Timing Error Statistics for Wireless OFDM Systems

Athaudage, Chandranath R; Jayalath, Anagiyaddage Dhammik
Fonte: Institute of Electrical and Electronics Engineers (IEEE Inc) Publicador: Institute of Electrical and Electronics Engineers (IEEE Inc)
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
37.28%
Estimation and tracking of the frequency-selective time-varying channel response is a challenging task for wireless communication systems incorporating coherent OFDM. In pilot-symbol-assisted (PSA) OFDM systems, the minimum mean-square-error (MMSE) estimator provides the optimum performance based on the channel statistics (channel correlation function and SNR). In OFDM systems, FFT-block timing error introduces a linear phase rotation to data modulated on individual subcarriers. An MMSE channel estimator designed only using the wireless channel statistics performs only sub-optimally when sub-carrier phase rotations due to block timing errors are present. In this paper, we show that by using the block timing error statistics of the OFDM time-synchronizer the performance of the MMSE channel estimation can be significantly improved. Numerical results show that the bit-error-probability (BEP) performance degradation due to timing errors can be almost completely recovered by the proposed technique.

Adaptive MMSE Maximum Likelihood CDMA Multiuser Detection

Borah, D
Fonte: Institute of Electrical and Electronics Engineers (IEEE Inc) Publicador: Institute of Electrical and Electronics Engineers (IEEE Inc)
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
27.33%
The well known code division multiple access maximum likelihood receiver (MF-ML) uses a bank of matched filters as a generator of sufficient statistics for maximum likelihood detection of users' transmitted symbols. In this paper, the bank of matched filters is replaced by a bank of adaptive minimum mean squared error (MMSE) filters as the generator of sufficient statistics. This formal replacement of the MF bank by the adaptive MMSE filter bank has significant conceptual consequences and provides improvement by several performance measures. The adaptive MMSE-ML receiver's digital implementation is significantly computationally simplified. The advantages of the proposed adaptive MMSE-ML receiver over the MF-ML receiver are: 1) ability to perform joint synchronization, channel parameter estimation, and signal detection where the signal is sent over an unknown, slowly time-varying, frequency-selective multipath fading channel, 2) increased information capacity in a multicellular environment; and 3) significantly improved bit error rate (BER) performance in a multicellular mobile communications environment. The information capacity and the BER of the proposed MMSE-ML receiver are analyzed. Numerical results showing the BER performance of the MMSE-ML receiver in a multipath channel environment are presented.

Nível educacional e idade no desempenho no Miniexame do Estado Mental em idosos residentes na comunidade; Educational level and age and the performance on the Mini-Mental State Examination in community-dwelling elderly

Diniz, Breno Satler de Oliveira; Volpe, Fernando Madalena; Tavares, Almir Ribeiro
Fonte: Universidade de São Paulo. Faculdade de Medicina. Instituto de Psiquiatria Publicador: Universidade de São Paulo. Faculdade de Medicina. Instituto de Psiquiatria
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/01/2007 POR
Relevância na Pesquisa
27.33%
CONTEXTO: Baixo nível educacional é comum na população idosa brasileira e isso pode afetar a avaliação cognitiva pelos métodos usuais. OBJETIVO: Avaliar o impacto do nível educacional e da idade no desempenho no MEEM em idosos residentes na comunidade. MÉTODOS: Visitas domiciliares foram realizadas, entre agosto de 2001 e junho de 2002, numa comunidade de Belo Horizonte. Nessas visitas, o MEEM foi aplicado a indivíduos com idade acima de 65 anos. RESULTADOS: Foram examinados 176 indivíduos. A idade variou de 65 a 97 anos (mediana = 71 anos). O nível educacional variou do analfabetismo a 13 anos de escolaridade (mediana = 3 anos); a pontuação no MEEM variou de 1 a 30 (mediana = 23 pontos). Tanto a idade quanto o nível educacional produziram influência estatisticamente significante na pontuação no MEEM (p < 0,001 e p < 0,0001, respectivamente). CONCLUSÃO: Em idosos com baixo nível educacional, quanto maior a escolaridade do indivíduo, melhor é o seu desempenho no MEEM. Ao mesmo tempo, quanto maior a sua idade, pior é a sua pontuação no MEEM.; BACKGROUND: Low educational level is common among Brazilian elderly and can affect the results of usual cognitive testing. OBJECTIVE: To evaluate the impact of age, and educational level on MMSE performance...