How Do Drivers Perceive Risks During Automated Driving Scenarios? An fNIRS Neuroimaging Study.

OBJECTIVE: Using brain haemodynamic responses to measure perceived risk from traffic complexity during automated driving. BACKGROUND: Although well-established during manual driving, the effects of driver risk perception during automated driving remain unknown. The use of fNIRS in this paper for assessing drivers' states posits it could become a novel method for measuring risk perception. METHODS: Twenty-three volunteers participated in an empirical driving simulator experiment with automated driving capability. Driving conditions involved suburban and urban scenarios with varying levels of traffic complexity, culminating in an unexpected hazardous event. Perceived risk was measured via fNIRS within the prefrontal cortical haemoglobin oxygenation and from self-reports. RESULTS: Prefrontal cortical haemoglobin oxygenation levels significantly increased, following self-reported perceived risk and traffic complexity, particularly during the hazardous scenario. CONCLUSION: This paper has demonstrated that fNIRS is a valuable research tool for measuring variations in perceived risk from traffic complexity during highly automated driving. Even though the responsibility over the driving task is delegated to the automated system and dispositional trust is high, drivers perceive moderate risk when traffic complexity builds up gradually, reflected in a corresponding significant increase in blood oxygenation levels, with both subjective (self-reports) and objective (fNIRS) increasing further during the hazardous scenario. APPLICATION: Little is known regarding the effects of drivers' risk perception with automated driving. Building upon our experimental findings, future work can use fNIRS to investigate the mental processes for risk assessment and the effects of perceived risk on driving behaviours to promote the safe adoption of automated driving technology.

Under pressure: Effect of a ransomware and a screen failure on trust and driving performance in an automated car simulation.

One major challenge for automated cars is to not only be safe, but also secure. Indeed, connected vehicles are vulnerable to cyberattacks, which may jeopardize individuals' trust in these vehicles and their safety. In a driving simulator experiment, 38 participants were exposed to two screen failures: silent (i.e., no turn signals on the in-vehicle screen and instrument cluster) and explicit (i.e., ransomware attack), both while performing a non-driving related task (NDRT) in a conditionally automated vehicle. Results showed that objective trust decreased after experiencing the failures. Drivers took over control of the vehicle and stopped their NDRT more often after the explicit failure than after the silent failure. Lateral control of the vehicle was compromised when taking over control after both failures compared to automated driving performance. However, longitudinal control proved to be smoother in terms of speed homogeneity compared to automated driving performance. These findings suggest that connectivity failures negatively affect trust in automation and manual driving performance after taking over control. This research posits the question of the importance of connectivity in the realm of trust in automation. Finally, we argue that engagement in a NDRT while riding in automated mode is an indicator of trust in the system and could be used as a surrogate measure for trust.

Emotional experience in individual and cooperative traditional games. A gender perspective / Experiencia emocional en juegos tradicionales individuales y cooperativos. Una perspectiva de género

This study explored the effect of gender (GE) and group gender composition (GGEC) on men’s and women’s experiences of emotions when taking part in different games. To formulate our hypotheses we used a theoretical framework formed by the theories of Lazarus and Bisquerra on the construct of emotional competence and well-being and their relationship with gender stereotypes, Parlebas’s motor action theory and previous results of empirical research related to games, emotions and gender relations. The participants (218 university students, Mage = 20.3, SD = 2.73) completed twelve sessions of individual games (IG) and cooperative games (CG). The results showed that GE and GGEC were predictors of the experience of positive emotions and that males were more likely to experience negative emotions in both games. The findings highlight gender differences and could help physical education teachers to avoid activities that reinforce the hierarchies and inequalities associated with gender and sex role stereotypes (AU)

Este estudio exploró el efecto del género (GE) y la composición del género del grupo (CGEC) en experiencias emocionales de hombres y mujeres cuando participaron en diferentes juegos. Para formular nuestra hipótesis se hizo uso del marco teórico elaborado a partir de las teorías de Lazarus y Bisquerra en relación al constructo de la competencia emocional y el bienestar y su relación con estereotipos de género, así como la teoría de acción motriz de Parlebas y resultados previos de la investigación empírica relativa a juegos, emociones y género. Los participantes (218 estudiantes universitarios, Medad = 20.3, DT = 2.73) realizaron doce sesiones de Juegos individuales (IG) y de Juegos cooperativos (CG). Los resultados mostraron que GE y GGEC fueron predictores de la experiencia de emociones positivas y que los hombres expresaron más emociones negativas en ambos juegos. Los hallazgos muestran diferencias de género y podrían ayudar a los profesores de educación física a evitar actividades que promuevan jerarquías y desigualdades asociadas al género y a los estereotipos de sexo (AU)

Mood states when playing alone or in cooperation: two unequal motor and affective experiences / Estados de ánimo al jugar en solitario o en cooperación: dos vivencias motrices y afectivas desiguales

This study analyzed the effect of the variables: game type (individual or cooperative), competition, gender, students' association type and beginning-end of the session on the university students' moods. 201 Physical Education college students participated. After having received an initial instruction concerning moods, participants executed 2 sessions involving cooperative games and 2 individual games. The POMS scale was filled in both at the beginning and at the end of each session. The data were analyzed using generalized estimating equations. Among the main findings, we can point out that positive emotional states increase significantly when cooperative games are applied, with competition. Negative moods are more present in individual games, with no competition, when practiced by men and when they are organized in separate groups. All these factors contribute towards knowing the influence of play on the training of the future teachers of a modern physical education, in which there is the intention of promoting such important aspects as socioemotional well-being and co-education

Este estudio analizó el efecto de las variables: tipo de juego (en solitario o cooperativo), competición, género, tipo de agrupación del alumnado e inicio-final de la sesión sobre los estados de ánimo de alumnado universitario. Participaron 201 estudiantes universitarios de Educación Física. Tras recibir una formación inicial sobre estados de ánimo, los participantes realizaron 2 sesiones con juegos cooperativos y 2 en solitario. Al inicio y final de cada sesión se rellenó la escala POMS. Los datos se analizaron mediante ecuaciones de estimación generalizadas. Entre los principales hallazgos destacamos que los estados de ánimo positivos aumentan significativamente al aplicar juegos cooperativos, con competición. Los estados de ánimo negativos están más presentes en los juegos en solitario, sin competición, al ser practicados por los hombres, y al estar organizados en grupos separados. Todo ello contribuye a conocer la aportación del juego en la formación de futuros docentes de una educación física moderna en la cual se pretenda promover aspectos tan importantes como el bienestar socioemocional y la coeducación

Relationship between traditional games and the intensity of emotions experienced by participants.

PURPOSE: The aims of this study were to analyze the intensity of emotions (positive, negative, or ambiguous) produced when players took part in traditional games with a different social structure and to examine the explanations given by those participants for these emotional experiences. METHOD: Participants (N = 556) were recruited from 4 Spanish universities. After taking part in each of the games, they were asked to complete the Games and Emotions Questionnaire to indicate the intensity of their emotional experiences and to explain what, in their view, had led to the strongest emotion felt. RESULTS: The application of a mixed-methods approach identified statistically significant differences in relation to 3 variables. These were (a) the type of emotion, (b) motor domain, and (c) type of result (win, loss, and noncompetitive). The intensity of positive emotions was higher in cooperative games and lower in individual games. Comments referring to negative emotions were more frequent as the social structure of games became more complex (minimal presence of individual games and predominance of cooperation-opposition games). Winning was associated with the highest intensity ratings of positive and ambiguous emotions, whereas being defeated produced the highest values for negative emotions. The intensity ratings for negative emotions were lower in noncompetitive games than in games where players lost. CONCLUSION: The results confirm that traditional games can play a key role in relation to the emotional facets of physical education.

Efecto de la cooperación motriz en la vivencia emocional positiva: perspectiva de género / Efeito da cooperação motriz na vivência emocional positiva: perspectiva de gênero / Effect of motor cooperation on positive emotional: a gender perspective

Se investigó, desde la perspectiva de género, la vivencia emocional suscitada con la práctica de situaciones motrices cooperativas. Participaron 309 estudiantes de 4 universidades españolas. Se empleó la escala validada de juegos y emociones (GES). Tras cada tarea, los alumnos anotaron la intensidad experimentada en las trece emociones consideradas y comentaron brevemente las causas que originaron la emoción más intensa. Se emplearon métodos mixtos al complementar el análisis de los datos cuantitativos con el estudio de comentarios cualitativos. Se confirmó la aportación de las situaciones motrices de juegos tradicionales, expresión e introyección para promover experiencias emocionales positivas en mujeres y hombres

Investigou-se, desde uma perspectiva de gênero, a vivência emocional provocada pela prática de situações motrizes cooperativas. Participaram 309 estudantes de quatro universidades espanholas. Utilizou-se a escala validada de jogos e emoções (GES). Depois de cada tarefa, os alunos indicaram a intensidade experimentada nas treze emoções consideradas e comentaram brevemente as causas que originaram a emoção mais intensa. Utilizouse métodos mistos ao complementar a análise dos dados quantitativos com o estudo de comentários qualitativos. Confirmou-se a contribuição de situações motrizes de jogos tradicionais, expressão e introjeção para promover emoções positivas em mulheres e homens

We examined the relationship between gender and the experience of in the context of cooperative motor tasks. Participants were 309 students from four Spanish universities. Emotions were rated using a validated instrument (GES; Games and Emotions Scale). After each task, students were asked to rate the intensity of thirteen emotions, and to comment briefly on why they thought they had experienced the strongest emotion. A mixed methods approach was used, combining the analysis of quantitative data with an analysis of students' comments. The results confirmed the important contribution which traditional games, motor expression and the internalization of motor skills can make in terms of promoting positive emotional experiences in women and men

Immigrants do not transmit tuberculosis more than indigenous patients in Catalonia (Spain).

BACKGROUND: Immigrants may not transmit tuberculosis (TB) more than indigenous patients. The objective was to study the prevalence of TB infection among contacts of immigrant and indigenous TB patients and the risk factors associated with latent TB infection. METHODS: Contacts of TB cases recorded in 2005 and 2006 were surveyed using a standardized Health Department questionnaire. Infections were diagnosed using the tuberculin skin test (TST) (cut-off ≥ 5 mm). The risk of infection was determined by multivariate logistic regression and the adjusted odds ratios (aOR) with the 95% confidence intervals (CI) were calculated. RESULTS: The study of contacts was completed in 1329 cases of TB. The prevalence of infection was 32.3% (3038/9406) in all contacts, 41.4% in contacts of immigrant cases and 29.2% in contacts of indigenous cases. In the multivariate analysis, immigrant index cases were not associated with an increased risk (aOR = 0.9; 95%CI: 0.8-1.0). The prevalence of TST conversion was 10.0% (296/2969) in all contacts, 11.2% in immigrant contacts and 9.7% in indigenous contacts (p = 0.158). CONCLUSIONS: Immigrants do not transmit TB more than indigenous TB patients. Infections which may have occurred in the countries of origin of immigrants were detected by the systematic study of contacts.

Using the WHOQOL-BREF in persons with dementia: a validation study.

Increasing evidence suggests that persons with early dementia can give reliable and valid assessments about their own quality of life (QOL), thereby improving accuracy, and reducing the need for proxy informants. The objective of this study was to examine QOL in persons diagnosed with dementia (Diagnostic and Statistical Manual of Mental Disorder-IV) using a battery of subjective assessments including the new World Health Organization Quality of Life (WHOQOL-BREF). Persons with mild-to-moderate dementia (n=104) were recruited and interviewed at 6 Spanish centers to obtain sociodemographic information, health perceptions, depressive symptoms (Geriatric Depression Scale 15-item version), functional ability (Barthel Index), generic QOL (WHOQOL-BREF), and specific QOL (DEMQOL-28). Analysis was performed using classical psychometric methods. Internal consistency reliability for the WHOQOL-BREF domains ranged from moderate (0.54 for social) to good (0.79 for psychological). Test-retest reliability (intraclass correlation) ranged from moderate (0.51 for psychological) to good (0.70 for physical). Associations were confirmed between WHOQOL-BREF domains with DEMQOL-28, Geriatric Depression Scale 15-item version, and Barthel dimensions. With regard to contrasting groups' differences, WHOQOL-BREF scores significantly differentiated between healthy and unhealthy and depressed and nondepressed participants. This study is the first to report on the use of the WHOQOL-BREF in persons with mild-to-moderate dementia. These results indicate that it is a useful tool in assessing these groups, as it includes important dimensions commonly omitted from other dementia measures.

Calidad de vida global en personas con demencia / Overall quality of life in persons with dementia

Objetivo. Evaluar la calidad de vida (CV) global en personas con demencia e investigar las variables asociadas con la percepción subjetiva de la CV. Pacientes y métodos. Se llevó a cabo un estudio transversal en seis centros de Barcelona y Tarragona. Un total de 99 personas con demencia leve-moderada que vivían en casa con un cuidador conocido completaron una entrevista cara-cara que incluía información sociodemográfica, percepción del estado de salud, un listado de problemas crónicos de salud, sintomatología depresiva, estado funcional, aspectos positivos, sentido de la vida y satisfacción con las relaciones personales. La CV global se evaluó con la pregunta global del World Health Organization Quality of Life-BREF. Resultados. El 40,6% de los entrevistados consideró su CV como buena/muy buena. Los análisis univariados de regresión logística ordinal y binaria no mostraron asociación entre CV con datos sociodemográficos, gravedad de la demencia ni estado funcional, pero sí con las otras variables de estudio. Los análisis multivariados de la regresión logística ordinal y binaria mostraron que una mejor percepción de salud y mayor satisfacción con las relaciones personales se asociaban con mejor CV. Asimismo, en el análisis multivariado de regresión logística ordinal, mejor CV se asoció con un menor número de síntomas depresivos, y en el análisis de regresión logística binaria, con disfrutar de la vida y menor gravedad de la demencia. Conclusiones. Personas con demencia leve-moderada pueden informar sobre su CV y estados subjetivos. Además de los aspectos relacionados con la salud, aspectos positivos y las relaciones personales deberían evaluarse sistemáticamente en esta población (AU)

Aim. To assess overall quality of life (QoL) among persons with dementia and to investigate variables associated with subjective perception of QoL. Patients and methods. This was a cross-sectional study in six health and social care centres in Barcelona and Tarragona. Ninety nine persons with mild-moderate dementia, living at home with a known caregiver completed a face-to-face interview including sociodemographic information; health perception, a list of chronic medical conditions, depressive symptoms and activities of daily living. Overall QoL was measured with the single item of the World Health Organization Quality of Life-BREF.Results. 40.6% assessed their overall QoL as very good/good. Univariate logistic regression analyses showed a lack of association between QoL with sociodemographic information, severity of dementia and functioning, but significant association between QoL with depressive symptoms, satisfaction with relationships, enjoying life and meaning in life. Ordinal and binary multivariate regression analysis showed that better perception of health and greater satisfaction with personal relationships was associated with better QoL. In addition, fewer depressive symptoms in the ordinal multivariate regression analysis and dementia severity and enjoy life in the binary regression analysis appeared significant. Conclusions. Persons with mild-moderate dementia can inform about their overall QoL and subjective states. In addition to health status, other dimensions, as personal relationships and positive aspects should be systematically assessed in this population (AU)

Utilidad de la escala de Zarit reducida en demencias / Short Zarit scale in dementias

Fundamento y objetivo: Reducir la escala de Zarit (EZ) en la valoración de la sobrecarga del cuidador en demencias. Pacientes y método: Estudio prospectivo en el que se administró la EZ a 85 cuidadores de pacientes con demencia ingresados o valorados en la consulta externa de nuestro hospital. Se realizó una prueba de jueces para la identificación de los factores de la sobrecarga analizada por cada ítem de la EZ y un estudio estadístico con análisis de regresión logística y curvas de ROC. Resultados: Se obtuvo una reducción de la escala a 4 ítems, con una especificidad del 94,7% y una sensibilidad del 98,5%. Conclusión: La EZ reducida es útil y de fácil manejo para la identificación de la sobrecarga del cuidador en demencias (AU)

Background and objectives: We aimed to reduce Zarit scale (ZS) for the assessment of caregiver burden in dementias. Patients and methods: Prospective study in which the ZS was performed to 85 caregivers of patients with dementia admitted to hospital. The field explored by each item was decided by an expert committee and a logistic regression and ROC curve were performed. Results: A ZS reduction to 4 items was achieved with a sensitivity 98,5% and specificity of 94,7%.Conclusions: A reduced Zarit scale is useful to idetifiy caregiver burden in dementias. It is also easy to use (AU)

[Short Zarit scale in dementias]. / Utilidad de la escala de Zarit reducida en demencias.

BACKGROUND AND OBJECTIVES: We aimed to reduce Zarit scale (ZS) for the assessment of caregiver burden in dementias. PATIENTS AND METHODS: Prospective study in which the ZS was performed to 85 caregivers of patients with dementia admitted to hospital. The field explored by each item was decided by an expert committee and a logistic regression and ROC curve were performed. RESULTS: A ZS reduction to 4 items was achieved with a sensitivity 98,5% and specificity of 94,7%. CONCLUSIONS: A reduced Zarit scale is useful to identifiy caregiver burden in dementias. It is also easy to use.

Stratification of the severity of critically ill patients with classification trees.

BACKGROUND: Development of three classification trees (CT) based on the CART (Classification and Regression Trees), CHAID (Chi-Square Automatic Interaction Detection) and C4.5 methodologies for the calculation of probability of hospital mortality; the comparison of the results with the APACHE II, SAPS II and MPM II-24 scores, and with a model based on multiple logistic regression (LR). METHODS: Retrospective study of 2864 patients. Random partition (70:30) into a Development Set (DS) n = 1808 and Validation Set (VS) n = 808. Their properties of discrimination are compared with the ROC curve (AUC CI 95%), Percent of correct classification (PCC CI 95%); and the calibration with the Calibration Curve and the Standardized Mortality Ratio (SMR CI 95%). RESULTS: CTs are produced with a different selection of variables and decision rules: CART (5 variables and 8 decision rules), CHAID (7 variables and 15 rules) and C4.5 (6 variables and 10 rules). The common variables were: inotropic therapy, Glasgow, age, (A-a)O2 gradient and antecedent of chronic illness. In VS: all the models achieved acceptable discrimination with AUC above 0.7. CT: CART (0.75(0.71-0.81)), CHAID (0.76(0.72-0.79)) and C4.5 (0.76(0.73-0.80)). PCC: CART (72(69-75)), CHAID (72(69-75)) and C4.5 (76(73-79)). Calibration (SMR) better in the CT: CART (1.04(0.95-1.31)), CHAID (1.06(0.97-1.15) and C4.5 (1.08(0.98-1.16)). CONCLUSION: With different methodologies of CTs, trees are generated with different selection of variables and decision rules. The CTs are easy to interpret, and they stratify the risk of hospital mortality. The CTs should be taken into account for the classification of the prognosis of critically ill patients.

Skin lesions after intensive care procedures: results of a prospective study.

PURPOSE: To define the skin lesions produced by procedures used in the intensive care unit (ICU) and to examine patients 12 months after discharge from the ICU. MATERIAL AND METHODS: This was a prospective clinical study in the 14-bed multidisciplinary ICU of a university hospital. Iatrogenic skin lesions (ISL) were examined in 316 patients after ICU discharge. RESULTS: A total of 189 patients were interviewed 12 months after ICU discharge. More than 85% of the patients had ISL after being discharged from the ICU. The patients with the highest Acute Physiology and Chronic Health Evaluation II score and longest average stay presented the highest number of ISLs. A total of 93 patients (49%) reported some skin lesions after 12 months. All patients who had undergone surgical tracheostomy reported the presence of a scar, but 4 of 24 patients who had undergone percutaneous tracheostomy reported no tracheostomy scar. Only 22% of all patients reported scars caused by vascular catheter access. About half (54.5%) of the patients reported secondary lesions caused by chest draining, and these were predominantly caused by the large-bore tube drainage. All patients reported the presence of a laparatomy scar. CONCLUSIONS: Most patients had identified skin lesions resulting from ICU procedures. Half of all patients were aware of their lesions and reported them at 12 months. Future research is needed to understand whether these lesions cause problems to survivor's quality of life and whether the lesions lead to increased health care utilization.

[Approach to the methodology of classification and regression trees]. / Aproximación a la metodología basada en árboles de decisión (CART). Mortalidad hospitalaria del infarto agudo de miocardio.

OBJECTIVE: To provide an overview of decision trees based on CART (Classification and Regression Trees) methodology. As an example, we developed a CART model intended to estimate the probability of intrahospital death from acute myocardial infarction (AMI). METHOD: We employed the minimum data set (MDS) of Andalusia, Catalonia, Madrid and the Basque Country (2001-2002), which included 33,203 patients with a diagnosis of AMI. The 33,203 patients were randomly divided (70% and 30%) into the development (DS; n = 23,277) and the validation (VS; n = 9,926) sets. The CART inductive model was based on Breiman's algorithm, with a sensitivity analysis based on the Gini index and cross-validation. We compared the results with those obtained by using both logistic regression (LR) and artificial neural network (ANN) (multilayer perceptron) models. The developed models were contrasted with the VS and their properties were evaluated with the area under the ROC curve (AUC) (95% confidence interval [CI]). RESULTS: In the DS, the CART showed an AUC = 0.85 (0.86-0.88), LR 0.87 (0.86-0.88) and ANN 0.85 (0.85-0.86). In the VS, the CART showed an AUC = 0.85 (0.85-0.88), LR 0.86 (0.85-0.88) and ANN 0.84 (0.83-0.86). CONCLUSIONS: None of the methods tested outperformed the others in terms of discriminative ability. We found that the CART model was much easier to use and interpret, because the decision rules generated could be applied without the need for mathematical calculations.

Aproximación a la metodología basada en árboles de decisión (CART). Mortalidad hospitalaria del infarto agudo de miocardio / Approach to the methodology of classification and regression trees

Objetivo: Realizar una aproximación a la metodología de árboles de decisión tipo CART (Classification and Regression Trees) desarrollando un modelo para calcular la probabilidad de muerte hospitalaria en infarto agudo de miocardio (IAM). Método: Se utiliza el conjunto mínimo básico de datos al alta hospitalaria (CMBD) de Andalucía, Cataluña, Madrid y País Vasco de los años 2001 y 2002, que incluye los casos con IAM como diagnóstico principal. Los 33.203 pacientes se dividen aleatoriamente (70 y 30 %) en grupo de desarrollo (GD = 23.277) y grupo de validación (GV = 9.926). Como CART se utiliza un modelo inductivo basado en el algoritmo de Breiman, con análisis de sensibilidad mediante el índice de Gini y sistema de validación cruzada. Se compara con un modelo de regresión logística (RL) y una red neuronal artificial (RNA) (multilayer perceptron). Los modelos desarrollados se contrastan en el GV y sus propiedades se comparan con el área bajo la curva ROC (ABC) (intervalo de confianza del 95%). Resultados: En el GD el CART con ABC = 0,85 (0,86-0,88), RL 0,87 (0,86-0,88) y RNA 0,85 (0,85-0,86). En el GV el CART con ABC = 0,85 (0,85-0,88), RL 0,86 (0,85-0,88) y RNA 0,84 (0,83-0,86). Conclusiones: Los 3 modelos obtienen resultados similares en su capacidad de discriminación. El modelo CART ofrece como ventaja su simplicidad de uso y de interpretación, ya que las reglas de decisión que generan pueden aplicarse sin necesidad de procesos matemáticos

Objective: To provide an overview of decision trees based on CART (Classification and Regression Trees) methodology. As an example, we developed a CART model intended to estimate the probability of intrahospital death from acute myocardial infarction (AMI). Method: We employed the minimum data set (MDS) of Andalusia, Catalonia, Madrid and the Basque Country (2001-2002), which included 33,203 patients with a diagnosis of AMI. The 33,203 patients were randomly divided (70% and 30%) into the development (DS; n = 23,277) and the validation (VS; n = 9,926) sets. The CART inductive model was based on Breiman's algorithm, with a sensitivity analysis based on the Gini index and cross-validation. We compared the results with those obtained by using both logistic regression (LR) and artificial neural network (ANN) (multilayer perceptron) models. The developed models were contrasted with the VS and their properties were evaluated with the area under the ROC curve (AUC) (95% confidence interval [CI]). Results: In the DS, the CART showed an AUC = 0.85 (0.86-0.88), LR 0.87 (0.86-0.88) and ANN 0.85 (0.85-0.86). In the VS, the CART showed an AUC = 0.85 (0.85-0.88), LR 0.86 (0.85-0.88) and ANN 0.84 (0.83-0.86). Conclusions: None of the methods tested outperformed the others in terms of discriminative ability. We found that the CART model was much easier to use and interpret, because the decision rules generated could be applied without the need for mathematical calculations

A more flexible parametric estimation of univariate reference intervals: a new method based on the GS-distribution.

BACKGROUND: Reference interval estimation is an important issue in clinical laboratories. Present methods are based either on data transformation or on non-parametric approaches. METHODS: We present a new technique based in a family of statistical distributions known as GS-distributions that provide a suitable model for continuous unimodal variables. We compare, both by simulation studies an on actual data, the reference intervals estimated by using non-parametric methods and data transformations suggested by the IFCC and those obtained by fitting a GS-distribution. Simulated data are generated from various distributions to evaluate the accuracy of these methods. In each case, confidence intervals for the resulting reference intervals are obtained by bootstrap. RESULTS: In all the cases, the GS-distribution based method provides comparable or more accurate results than the non-parametric methods. In most cases, the proposed method produces better results than those obtained by transforming the original data. CONCLUSIONS: Our results suggest that the method for computing reference intervals based on GS-distribution is a valid alternative for the current non-parametric methods.

[Short Zarit scale in palliative care]. / Escala de Zarit reducida en cuidados paliativos.

BACKGROUND AND OBJECTIVE: We aimed to reduce the Zarit scale (ZS) for the assessment of caregiver burden in palliative care. PATIENTS AND METHOD: ZS was performed in 61 caregivers of palliative care patients admitted to hospital. The field explored by each item was decided by an expert committee and a logistic regression and ROC curve were performed. RESULTS: ZS reduction to 7 items was achieved with a sensitivity and specificity of 100%. CONCLUSIONS: A reduced Zarit scale is useful to identify caregiver burden in palliative care. It is also easy to use.

Escala de Zarit reducida en cuidados paliativos / Short Zarit scale in palliative care

FUNDAMENTO Y OBJETIVO: Reducir la escala de Zarit (EZ) en la valoración de la claudicación en cuidados paliativos. PACIENTES Y MÉTODO: Se administró la EZ a61 cuidadores de pacientes paliativos ingresados. Se realizó una prueba de jueces para la identificación de las dimensiones de personalidad analizadas por cada ítem de la EZ, así como un estudio estadístico con análisis de regresión logística y curvas de eficacia diagnóstica. RESULTADOS: Se obtuvo una reducción de la escala a 7 ítems, con una especificidad y sensibilidad del 100%.CONCLUSIONES: La EZ reducida es útil y de fácil manejo para la identificación de la claudicación familiar en cuidados paliativos

BACKGROUND AND OBJECTIVE: We aimed to reduce the Zarit scale (ZS) for the assessment of caregiver burden in palliative care. PATIENTS AND METHOD: ZS was performed in 61caregivers of palliative care patients admitted to hospital. The field explored by each item was decided by an expert committee and a logistic regression and ROC curve were performed. RESULTS: ZS reduction to 7 items was achieved with a sensitivity and specificity of 100%. CONCLUSIONS: A reduced Zarit scale is useful to identify caregiver burden in palliative care. It is also easy to use

[Methodological approach to the use of artificial neural networks for predicting results in medicine]. / Aproximación metodológica al uso de redes neuronales artificiales para la predicción de resultados en medicina.

In clinical practice, there is an increasing interest in obtaining adequate models of prediction. Within the possible available alternatives, the artificial neural networks (ANN) are progressively more used. In this review we first introduce the ANN methodology, describing the most common type of ANN, the Multilayer Perceptron trained with backpropagation algorithm (MLP). Then we compare the MLP with the Logistic Regression (LR). Finally, we show a practical scheme to make an application based on ANN by means of an example with actual data. The main advantage of the RN is its capacity to incorporate nonlinear effects and interactions between the variables of the model without need to include them a priori. As greater disadvantages, they show a difficult interpretation of their parameters and large empiricism in their process of construction and training. ANN are useful for the computation of probabilities of a given outcome based on a set of predicting variables. Furthermore, in some cases, they obtain better results than LR. Both methodologies, ANN and LR, are complementary and they help us to obtain more valid models.

Estimating conditional distributions using a method based on S-distributions reference percentile curves for body mass index in Spanish children.

BACKGROUND: Reference intervals are a fundamental tool for characterizing the health status in a given population and play a central role in defining diagnostic values in clinical applications. Estimation of the conditional distribution of a variable, as the body mass index (BMI), is necessary for providing reference values when there is a trend as a function of the covariate. SUBJECTS AND METHOD: We studied 1453 boys and young between 5 and 16 years old measured in a study carried out in the schools of Lleida (Spain). BMI conditional distributions with age have been derived using a new parametric method based on the one proposed by Sorribas et al. [Stat. Med. (2000) 19:697-713]. This method is based on S-distributions as a parametric model for the distribution and uses maximum likelihood estimation of the conditional distribution. RESULTS: The methods commonly used for estimating reference curves are based on a smoothing of sample quantiles using different techniques. However, these methods do not provide information on the conditional distribution of the target variable. Our method provides an estimation of such distribution and the corresponding reference curves for the quantiles as a function of a covariate, in our case age. CONCLUSIONS: The suggested methodology provides appropriate reference quantiles for the BMI. Our results allow characterizing the change in distribution within the age range considered. Besides describing a raise in BMI with age, we observe an increase in dispersion around puberty. This must be considered when using BMI as a diagnostic variable.