An Automated Approach for the Detection of Alzheimer's Disease From Resting State Electroencephalography.

Early detection is crucial to control the progression of Alzheimer's disease and to postpone intellectual decline. Most current detection techniques are costly, inaccessible, or invasive. Furthermore, they require laborious analysis, what delays the start of medical treatment. To overcome this, researchers have recently investigated AD detection based on electroencephalography, a non-invasive neurophysiology technique, and machine learning algorithms. However, these approaches typically rely on manual procedures such as visual inspection, that requires additional personnel for the analysis, or on cumbersome EEG acquisition systems. In this paper, we performed a preliminary evaluation of a fully-automated approach for AD detection based on a commercial EEG acquisition system and an automated classification pipeline. For this purpose, we recorded the resting state brain activity of 26 participants from three groups: mild AD, mild cognitive impairment (MCI-non-AD), and healthy controls. First, we applied automated data-driven algorithms to reject EEG artifacts. Then, we obtained spectral, complexity, and entropy features from the preprocessed EEG segments. Finally, we assessed two binary classification problems: mild AD vs. controls, and MCI-non-AD vs. controls, through leave-one-subject-out cross-validation. The preliminary results that we obtained are comparable to the best reported in literature, what suggests that AD detection could be automatically detected through automated processing and commercial EEG systems. This is promising, since it may potentially contribute to reducing costs related to AD screening, and to shortening detection times, what may help to advance medical treatment.

Discriminative validity of an abbreviated Semantic Verbal Fluency Test.

Semantic verbal fluency (SVF) is one of the most widely used tests for cognitive assessment due to its diagnostic utility (DU). OBJECTIVE: our objective is to evaluate the DU to detect cognitive impairment (CI) of a short version of the SVF applied in 30 seconds (SVF1-30). METHODS: a prospective sample of consecutive patients evaluated in a Neurology Unit between December 2016 and December 2017 were assessed with the Global Deterioration Scale (GDS), 30-second and 60-second SVF tests (animals), and the Fototest, which includes a fluency task of people's names. The DU for CI was evaluated by the area under the ROC curve and effect size ("d" Cohen). RESULTS: the study included 1012 patients (256 with CI, 395 with dementia). SVF1-30 shows a good correlation with GDS stage. The DU of SVF1-30 is identical to that of the classical version, applied in 60 seconds, (SVFtotal) for CI (0.89 ± 0.01; p > 0.50), and shows no significant difference for dementia (0.85 ± 0.01 vs. 0.86 ± 0.01, p > 0.15). DISCUSSION: the DU of SVF1-30 is similar to that of the SVFtotal, allowing a reduction in examination time with no loss of discriminative capacity.

A fluência verbal semântica (SVF) é um dos testes mais utilizados na avaliação cognitiva devido à sua utilidade diagnóstica (UD). OBJETIVO: Nosso objetivo foi o de avaliar o DU de uma versão abreviada do SVF aplicado em 30 segundos (SVF1-30) para a detecção do comprometimento cognitivo (CC). MÉTODOS: Amostra prospectiva de pacientes avaliados em uma Unidade de Neurologia entre dezembro de 2016 e dezembro de 2017. Global Deterioration Scale (GDS), um teste de SVF (animais), registrando os resultados em 30 e 60 segundos e Fototest, que inclui uma tarefa de fluência de nomes de pessoas foram aplicadas. A UD para CC foi avaliada pela área sob a curva ROC e o tamanho do efeito ("d" Cohen). RESULTADOS: foram incluídos 1012 sujeitos (256 CC e 395 demência). O SVF1-30 mostrou uma boa correlação com o estágio GDS. A UD de SVF1-30 é idêntico ao da versão clássica (SVFtotal) para CC (0,89 ± 0,01; p > 0,50) e sem diferença significativa para demência (0,85 ± 0,01 vs. 0,86 ± 0,01; p > 0,15). DISCUSSÃO: a UD do SVF1-30 é similar ao SVFtotal, o que permite diminuir o tempo de exploração sem perder a capacidade discriminativa.

Discriminative validity of an abbreviated Semantic Verbal Fluency Test / Validade discriminativa de um teste abreviado de Fluência Verbal Semântica

ABSTRACT. Semantic verbal fluency (SVF) is one of the most widely used tests for cognitive assessment due to its diagnostic utility (DU). Objective: our objective is to evaluate the DU to detect cognitive impairment (CI) of a short version of the SVF applied in 30 seconds (SVF1-30). Methods: a prospective sample of consecutive patients evaluated in a Neurology Unit between December 2016 and December 2017 were assessed with the Global Deterioration Scale (GDS), 30-second and 60-second SVF tests (animals), and the Fototest, which includes a fluency task of people's names. The DU for CI was evaluated by the area under the ROC curve and effect size ("d" Cohen). Results: the study included 1012 patients (256 with CI, 395 with dementia). SVF1-30 shows a good correlation with GDS stage. The DU of SVF1-30 is identical to that of the classical version, applied in 60 seconds, (SVFtotal) for CI (0.89 ± 0.01; p > 0.50), and shows no significant difference for dementia (0.85 ± 0.01 vs. 0.86 ± 0.01, p > 0.15). Discussion: the DU of SVF1-30 is similar to that of the SVFtotal, allowing a reduction in examination time with no loss of discriminative capacity.

RESUMO. A fluência verbal semântica (SVF) é um dos testes mais utilizados na avaliação cognitiva devido à sua utilidade diagnóstica (UD). Objetivo: Nosso objetivo foi o de avaliar o DU de uma versão abreviada do SVF aplicado em 30 segundos (SVF1-30) para a detecção do comprometimento cognitivo (CC). Métodos: Amostra prospectiva de pacientes avaliados em uma Unidade de Neurologia entre dezembro de 2016 e dezembro de 2017. Global Deterioration Scale (GDS), um teste de SVF (animais), registrando os resultados em 30 e 60 segundos e Fototest, que inclui uma tarefa de fluência de nomes de pessoas foram aplicadas. A UD para CC foi avaliada pela área sob a curva ROC e o tamanho do efeito ("d" Cohen). Resultados: foram incluídos 1012 sujeitos (256 CC e 395 demência). O SVF1-30 mostrou uma boa correlação com o estágio GDS. A UD de SVF1-30 é idêntico ao da versão clássica (SVFtotal) para CC (0,89 ± 0,01; p > 0,50) e sem diferença significativa para demência (0,85 ± 0,01 vs. 0,86 ± 0,01; p > 0,15). Discussão: a UD do SVF1-30 é similar ao SVFtotal, o que permite diminuir o tempo de exploração sem perder a capacidade discriminativa.

Creation and design of a test for the Evaluation of Upper Limb Apraxia (EULA) based on a cognitive model: a pilot study.

INTRODUCTION: Apraxia is regarded as neurological disorder characterized by a loss of ability to execute and carry out skilled movements and gestures despite intact motor and sensory systems, coordination, and comprehension. As reflected in the specialized literature, there are currently few tests that provide a global evaluation of this syndrome. This research created and designed a test for the Evaluation of Upper Limb Apraxia (EULA), based on theoretical models of apraxia. SUBJECTS AND METHODS: A sample of 57 patients was selected with subjective cognitive manifestations (complaints of cognitive impairment) and 39 subjects without cognitive impairment. Both groups were given the EULA test as well as other tests. The structure of the EULA was verified with principal components factor analysis, and the reliability and validity of this instrument were also calculated. RESULTS: The factor analysis classified all of the items in the test in nine factors with an explained total variance of 69.91%. The high reliability of the test was reflected in a Cronbach's alpha of 0.929 and a Guttman split-half coefficient of 0.870. The construct validity was also satisfactory as shown in the significant correlation of six of the nine factors in the test with two other well-known apraxia subtests. CONCLUSIONS: The healthy subjects had a higher test score than the subjects with complaints of cognitive impairment, which confirmed the reliability and construct validity of the EULA.

TITLE: Creacion y diseño de un test para la evaluacion de la apraxia de los miembros superiores (EULA) basado en un modelo cognitivo: un estudio piloto.Introduccion. La apraxia es un trastorno neurologico caracterizado por la dificultad en la ejecucion de habilidades gestuales aprendidas a pesar de tener preservados los sistemas motores y sensoriales, la coordinacion y la comprension, asi como de una adecuada colaboracion. Actualmente, existen pocas herramientas validadas que evaluen este sindrome de manera global. En el presente estudio, se ha creado y diseñado un test para la evaluacion de la apraxia de los miembros superiores (EULA), basado en modelos teoricos. Sujetos y metodos. Se selecciono una poblacion de 57 pacientes con quejas subjetivas de deterioro cognitivo y 39 personas sin quejas ni deterioro cognitivo, a las cuales se les administro el test EULA, entre otros tests. Se realizo un analisis factorial de componentes principales y un calculo tanto de la fiabilidad como de la validez de dicho instrumento. Resultados. El analisis factorial agrupo en nueve factores todos los items de la prueba, con una varianza total explicada del 69,91%. El test ha mostrado una alta fiabilidad, con un alfa de Cronbach de 0,929 y un coeficiente de Guttman de 0,870 con el metodo de las dos mitades. El test tambien mostro tener una adecuada validez de constructo, al existir correlacion significativa entre seis factores del test y dos subtests de apraxia. Conclusiones. El test EULA, surgido de las propuestas de evaluacion a nivel teorico desarrolladas por diferentes autores, muestra una puntuacion superior en personas sanas respecto a personas con manifestaciones subjetivas de deterioro cognitivo, ademas de tener una alta fiabilidad y validez de constructo.

A systematic review and meta-analysis of the diagnostic accuracy of the Phototest for cognitive impairment and dementia / Revisão sistemática e meta-análise da acurácia diagnóstica do Phototest em comprometimento cognitivo e demência

The recently developed Phototest is a simple, easy and very brief test for detecting cognitive impairment or dementia. OBJECTIVE: To evaluate the diagnostic accuracy of the Phototest for detecting cognitive impairment or dementia. METHODS: We used a manually created database to search for studies evaluating the Phototest diagnostic yield and performed an initial meta-analysis to determine sensitivity (Sn) and specificity (Sp) of diagnostic parameters. We also performed a second meta-analysis of individual participant data. RESULTS: In total, 6 studies were included in the meta-analysis. For dementia, Sn was 0.85 (95% CI, 0.82-0.88) and Sp 0.87 (95% CI, 0.85-0.99); for cognitive impairment, Sn was 0.80 (95% CI, 0.77-0.92) and Sp 0.88 (95% CI, 0.86-0.90). In the individual data meta-analysis, 1565 subjects were included, where best cut-off points for dementia and for cognitive impairment were 26/27 (Sn=0.89 (95% CI 0.85-0.91), Sp=0.84 (95% CI, 0.82-0.91)) and 28/29 (Sn=0.79 (95% CI, 0.76-0.81), Sp=0.88 (95% CI, 0.86-0.90)), respectively. CONCLUSION: Phototest has good diagnostic accuracy for dementia and cognitive impairment. It is brief, simple and can be used in illiterate persons. This makes it suitable for use in primary care settings and/or in subjects with low educational level.

Phototest é um teste simples, fácil e muito rápido para detecção de comprometimento cognitivo e demência recentemente desenvolvido. OBJETIVO: Avaliar a acurácia diagnostica do Phototest para detecção de comprometimento cognitivo e demência. MÉTODOS: Nós usamos um banco de dados manualmente criado para estudos que avaliassem a capacidade diagnóstica do Phototest e realizamos uma meta-análise para determinar a sensibilidade (Sn) e especificidade (Ep) dos parâmetros diagnósticos. Nós também realizamos uma segunda meta-análise dos dados individuais dos participantes. RESULTADOS: Um total de seis estudos foram incluídos na meta-análise. Para demência a Sn foi 0.85 (95% CI, 0,82-0,88) e Ep 0,87 (95% CI, 0,85-0,99); para comprometimento cognitivo a Sn foi 0,80 (95% CI, 0,77-0,92) e Sp 0,88 (95% CI, 0,86-0,90). Na meta-análise de dados individuais, 1565 foram incluídos, os melhores escores de corte para demência e para comprometimento cognitivo foram 26/27 (Sn=0,89 (95% CI 0,85-0,91), Ep=0,84 (95% CI, 0,82-0,91)) e 28/29 (Sn=0,79 (95% CI, 0,76-0,81), Ep=0,88 (95% CI, 0,86-0,90)), respectivamente. CONCLUSÃO: Photest tem boa acurácia diagnostica para demência e comprometimento cognitivo. É breve, simples e pode ser usado em pessoas analfabetas. Tornando-o apropriado para o uso em cuidados primários e/ou sujeitos com baixo nível educacional.

A systematic review and meta-analysis of the diagnostic accuracy of the Phototest for cognitive impairment and dementia.

The recently developed Phototest is a simple, easy and very brief test for detecting cognitive impairment or dementia. OBJECTIVE: To evaluate the diagnostic accuracy of the Phototest for detecting cognitive impairment or dementia. METHODS: We used a manually created database to search for studies evaluating the Phototest diagnostic yield and performed an initial meta-analysis to determine sensitivity (Sn) and specificity (Sp) of diagnostic parameters. We also performed a second meta-analysis of individual participant data. RESULTS: In total, 6 studies were included in the meta-analysis. For dementia, Sn was 0.85 (95% CI, 0.82-0.88) and Sp 0.87 (95% CI, 0.85-0.99); for cognitive impairment, Sn was 0.80 (95% CI, 0.77-0.92) and Sp 0.88 (95% CI, 0.86-0.90). In the individual data meta-analysis, 1565 subjects were included, where best cut-off points for dementia and for cognitive impairment were 26/27 (Sn=0.89 (95% CI 0.85-0.91), Sp=0.84 (95% CI, 0.82-0.91)) and 28/29 (Sn=0.79 (95% CI, 0.76-0.81), Sp=0.88 (95% CI, 0.86-0.90)), respectively. CONCLUSION: Phototest has good diagnostic accuracy for dementia and cognitive impairment. It is brief, simple and can be used in illiterate persons. This makes it suitable for use in primary care settings and/or in subjects with low educational level.

Phototest é um teste simples, fácil e muito rápido para detecção de comprometimento cognitivo e demência recentemente desenvolvido. OBJETIVO: Avaliar a acurácia diagnostica do Phototest para detecção de comprometimento cognitivo e demência. MÉTODOS: Nós usamos um banco de dados manualmente criado para estudos que avaliassem a capacidade diagnóstica do Phototest e realizamos uma meta-análise para determinar a sensibilidade (Sn) e especificidade (Ep) dos parâmetros diagnósticos. Nós também realizamos uma segunda meta-análise dos dados individuais dos participantes. RESULTADOS: Um total de seis estudos foram incluídos na meta-análise. Para demência a Sn foi 0.85 (95% CI, 0,82-0,88) e Ep 0,87 (95% CI, 0,85-0,99); para comprometimento cognitivo a Sn foi 0,80 (95% CI, 0,77-0,92) e Sp 0,88 (95% CI, 0,-0,90). Na meta-análise de dados individuais, 1565 foram incluídos, os melhores escores de corte para demência e para comprometimento cognitivo foram 26/27 (Sn=0,89 (95% CI 0,85-0,91), Ep=0,84 (95% CI, 0,82-0,91)) e 28/29 (Sn=0,79 (95% CI, 0,76-0,81), Ep=0,88 (95% CI, 0,86-0,90)), respectivamente. CONCLUSÃO: Photest tem boa acurácia diagnostica para demência e comprometimento cognitivo. É breve, simples e pode ser usado em pessoas analfabetas. Tornando-o apropriado para o uso em cuidados primários e/ou sujeitos com baixo nível educacional.

Utility of the mini-cog for detection of cognitive impairment in primary care: data from two spanish studies.

Objectives. To study the utility of the Mini-Cog test for detection of patients with cognitive impairment (CI) in primary care (PC). Methods. We pooled data from two phase III studies conducted in Spain. Patients with complaints or suspicion of CI were consecutively recruited by PC physicians. The cognitive diagnosis was performed by an expert neurologist, after formal neuropsychological evaluation. The Mini-Cog score was calculated post hoc, and its diagnostic utility was evaluated and compared with the utility of the Mini-Mental State (MMS), the Clock Drawing Test (CDT), and the sum of the MMS and the CDT (MMS + CDT) using the area under the receiver operating characteristic curve (AUC). The best cut points were obtained on the basis of diagnostic accuracy (DA) and kappa index. Results. A total sample of 307 subjects (176 CI) was analyzed. The Mini-Cog displayed an AUC (±SE) of 0.78 ± 0.02, which was significantly inferior to the AUC of the CDT (0.84 ± 0.02), the MMS (0.84 ± 0.02), and the MMS + CDT (0.86 ± 0.02). The best cut point of the Mini-Cog was 1/2 (sensitivity 0.60, specificity 0.90, DA 0.73, and kappa index 0.48 ± 0.05). Conclusions. The utility of the Mini-Cog for detection of CI in PC was very modest, clearly inferior to the MMS or the CDT. These results do not permit recommendation of the Mini-Cog in PC.

Diagnostic accuracy, effectiveness and cost for cognitive impairment and dementia screening of three short cognitive tests applicable to illiterates.

BACKGROUND: Illiteracy, a universal problem, limits the utilization of the most widely used short cognitive tests. Our objective was to assess and compare the effectiveness and cost for cognitive impairment (CI) and dementia (DEM) screening of three short cognitive tests applicable to illiterates. METHODS: Phase III diagnostic test evaluation study was performed during one year in four Primary Care centers, prospectively including individuals with suspicion of CI or DEM. All underwent the Eurotest, Memory Alteration Test (M@T), and Phototest, applied in a balanced manner. Clinical, functional, and cognitive studies were independently performed in a blinded fashion in a Cognitive Behavioral Neurology Unit, and the gold standard diagnosis was established by consensus of expert neurologists on the basis of these results. Effectiveness of tests was assessed as the proportion of correct diagnoses (diagnostic accuracy [DA]) and the kappa index of concordance (k) with respect to gold standard diagnoses. Costs were based on public prices at the time and hospital accounts. RESULTS: The study included 139 individuals: 47 with DEM, 36 with CI, and 56 without CI. No significant differences in effectiveness were found among the tests. For DEM screening: Eurotest (k = 0.71 [0.59-0.83], DA = 0.87 [0.80-0.92]), M@T (k = 0.72 [0.60-0.84], DA = 0.87 [0.80-0.92]), Phototest (k = 0.70 [0.57-0.82], DA = 0.86 [0.79-0.91]). For CI screening: Eurotest (k = 0.67 [0.55-0.79]; DA = 0.83 [0.76-0.89]), M@T (k = 0.52 [0.37-0.67]; DA = 0.80 [0.72-0.86]), Phototest (k = 0.59 [0.46-0.72]; DA = 0.79 [0.71-0.86]). There were no differences in the cost of DEM screening, but the cost of CI screening was significantly higher with M@T (330.7 ± 177.1 €, mean ± sd) than with Eurotest (294.1 ± 195.0 €) or Phototest (296.0 ± 196. 5 €). Application time was shorter with Phototest (2.8 ± 0.8 min) than with Eurotest (7.1 ± 1.8 min) or M@T (6.8 ± 2.2 min). CONCLUSIONS: Eurotest, M@T, and Phototest are equally effective. Eurotest and Phototest are both less expensive options but Phototest is the most efficient, requiring the shortest application time.

Effectiveness and costs of phototest in dementia and cognitive impairment screening.

BACKGROUND: To assess and compare the effectiveness and costs of Phototest, Mini Mental State Examination (MMSE), and Memory Impairment Screen (MIS) to screen for dementia (DEM) and cognitive impairment (CI). METHODS: A phase III study was conducted over one year in consecutive patients with suspicion of CI or DEM at four Primary Care (PC) centers. After undergoing all screening tests at the PC center, participants were extensively evaluated by researchers blinded to screening test results in a Cognitive-Behavioral Neurology Unit (CBNU). The gold standard diagnosis was established by consensus of expert neurologists. Effectiveness was assessed by the proportion of correct diagnoses (diagnostic accuracy [DA]) and by the kappa index of concordance between test results and gold standard diagnoses. Costs were based on public prices and hospital accounts. RESULTS: The study included 140 subjects (48 with DEM, 37 with CI without DEM, and 55 without CI). The MIS could not be applied to 23 illiterate subjects (16.4%). For DEM, the maximum effectiveness of the MMSE was obtained with different cutoff points as a function of educational level [k = 0.31 (95% Confidence interval [95%CI], 0.19-0.43), DA = 0.60 (95%CI, 0.52-0.68)], and that of the MIS with a cutoff of 3/4 [k = 0.63 (95%CI, 0.48-0.78), DA = 0.83 (95%CI, 0.80-0.92)]. Effectiveness of the Phototest [k = 0.71 (95%CI, 0.59-0.83), DA = 0.87 (95%CI, 0.80-0.92)] was similar to that of the MIS and higher than that of the MMSE. Costs were higher with MMSE (275.9 ± 193.3€ [mean ± sd euros]) than with Phototest (208.2 ± 196.8€) or MIS (201.3 ± 193.4€), whose costs did not significantly differ. For CI, the effectiveness did not significantly differ between MIS [k = 0.59 (95%CI, 0.45-0.74), DA = 0.79 (95%CI, 0.64-0.97)] and Phototest [k = 0.58 (95%CI, 0.45-0.74), DA = 0.78 (95%CI, 0.64-0.95)] and was lowest for the MMSE [k = 0.27 (95%CI, 0.09-0.45), DA = 0.69 (95%CI, 0.56-0.84)]. Costs were higher for MMSE (393.4 ± 121.8€) than for Phototest (287.0 ± 197.4€) or MIS (300.1 ± 165.6€), whose costs did not significantly differ. CONCLUSION: MMSE is not an effective instrument in our setting. For both DEM and CI, the Phototest and MIS are more effective and less costly, with no difference between them. However, MIS could not be applied to the appreciable percentage of our population who were illiterate.