Mindfulness-based stress reduction for breast cancer survivors (MBSR(BC)): evaluating mediators of psychological and physical outcomes in a large randomized controlled trial.

MBSR(BC) is known to have a positive impact on psychological and physical symptoms among breast cancer survivors (BCS). The cognitive mechanisms of "how" MBSR(BC) works was addressed in a recent study that found that there was strong consistent evidence that reduced emotional reactivity is a mediator and moderate consistent evidence that mindfulness, rumination, and worry were mediators. The purpose of this study, as part of a larger R01 trial, was to test whether positive effects achieved from the MBSR(BC) program were mediated through changes in increased mindfulness, decreased fear of breast cancer recurrence, and perceived stress. Female BCS > 21 years diagnosed with Stage 0-III breast cancer were randomly assigned to a 6-week MBSR(BC) or a Usual Care (UC)regimen. Potential mediators of 6- and 12-week outcomes were identified by analysis of covariance (ANCOVA), followed by formal mediational analyses of main effects of MBSR(BC) on 6- and 12-week outcomes, including percentage of total effects explained. Among 322 BCS (167 MBSR(BC) and 155 UC), fear of recurrence and perceived stress, but not mindfulness, mediated reductions in anxiety and fatigue at weeks 6 and 12, partially supporting our hypothesis of cognitive mechanisms of MBSR(BC). TRIAL REGISTRATION: Registration Number: NCT01177124 http://www.ClinicalTrials.gov.

The effects of mindfulness-based stress reduction on objective and subjective sleep parameters in women with breast cancer: a randomized controlled trial.

OBJECTIVE: The purpose of this study was to investigate the effects of mindfulness-based stress reduction for breast cancer survivors (MBSR(BC)) on multiple measures of objective and subjective sleep parameters among breast cancer survivors (BCS). METHODS: Data were collected using a two-armed randomized controlled design among BCS enrolled in either a 6-week MBSR(BC) program or a usual care (UC) group with a 12-week follow-up. The present analysis is a subset of the larger parent trial (ClinicalTrials.gov Identifier: NCT01177124). Seventy-nine BCS participants (mean age 57 years), stages 0-III, were randomly assigned to either the formal (in-class) 6-week MBSR(BC) program or UC. Subjective sleep parameters (SSP) (i.e., sleep diaries and the Pittsburgh Sleep Quality Index (PSQI)) and objective sleep parameters (OSP) (i.e., actigraphy) were measured at baseline, 6 weeks, and 12 weeks after completing the MBSR(BC) or UC program. RESULTS: Results showed indications of a positive effect of MBSR(BC) on OSP at 12 weeks on sleep efficiency (78.2% MBSR(BC) group versus 74.6% UC group, p = 0.04), percent of sleep time (81.0% MBSR(BC) group versus 77.4% UC group, p = 0.02), and less number waking bouts (93.5 in MBSR(BC) group versus 118.6 in the UC group, p < 0.01). Small nonsignificant improvements were found in SSP in the MBSR(BC) group from baseline to 6 weeks (PSQI total score, p = 0.09). No significant relationship was observed between minutes of MBSR(BC) practice and SSP or OSP. CONCLUSIONS: These data suggest that MBSR(BC) may be an efficacious treatment to improve objective and subjective sleep parameters in BCS.

Mindfulness based stress reduction (MBSR(BC)) in breast cancer: evaluating fear of recurrence (FOR) as a mediator of psychological and physical symptoms in a randomized control trial (RCT).

To investigate the mechanism(s) of action of mindfulness based stress reduction (MBSR(BC)) including reductions in fear of recurrence and other potential mediators. Eighty-two post-treatment breast cancer survivors (stages 0-III) were randomly assigned to a 6-week MBSR(BC) program (n = 40) or to usual care group (UC) (n = 42). Psychological and physical variables were assessed as potential mediators at baseline and at 6 weeks. MBSR(BC) compared to UC experienced favorable changes for five potential mediators: (1) change in fear of recurrence problems mediated the effect of MBSR(BC) on 6-week change in perceived stress (z = 2.12, p = 0.03) and state anxiety (z = 2.03, p = 0.04); and (2) change in physical functioning mediated the effect of MBSR(BC) on 6-week change in perceived stress (z = 2.27, p = 0.02) and trait anxiety (z = 1.98, p = 0.05). MBSR(BC) reduces fear of recurrence and improves physical functioning which reduces perceived stress and anxiety. Findings support the beneficial effects of MBSR(BC) and provide insight into the possible cognitive mechanism of action.

Randomized controlled trial of mindfulness-based stress reduction (MBSR) for survivors of breast cancer.

OBJECTIVES: Considerable morbidity persists among survivors of breast cancer (BC) including high levels of psychological stress, anxiety, depression, fear of recurrence, and physical symptoms including pain, fatigue, and sleep disturbances, and impaired quality of life. Effective interventions are needed during this difficult transitional period. METHODS: We conducted a randomized controlled trial of 84 female BC survivors (Stages 0-III) recruited from the H. Lee Moffitt Cancer and Research Institute. All subjects were within 18 months of treatment completion with surgery and adjuvant radiation and/or chemotherapy. Subjects were randomly assigned to a 6-week Mindfulness-Based Stress Reduction (MBSR) program designed to self-regulate arousal to stressful circumstances or symptoms (n=41) or to usual care (n=43). Outcome measures compared at 6 weeks by random assignment included validated measures of psychological status (depression, anxiety, perceived stress, fear of recurrence, optimism, social support) and psychological and physical subscales of quality of life (SF-36). RESULTS: Compared with usual care, subjects assigned to MBSR(BC) had significantly lower (two-sided p<0.05) adjusted mean levels of depression (6.3 vs 9.6), anxiety (28.3 vs 33.0), and fear of recurrence (9.3 vs 11.6) at 6 weeks, along with higher energy (53.5 vs 49.2), physical functioning (50.1 vs 47.0), and physical role functioning (49.1 vs 42.8). In stratified analyses, subjects more compliant with MBSR tended to experience greater improvements in measures of energy and physical functioning. CONCLUSIONS: Among BC survivors within 18 months of treatment completion, a 6-week MBSR(BC) program resulted in significant improvements in psychological status and quality of life compared with usual care.

A Large Randomized Trial: Effects of Mindfulness-Based Stress Reduction (MBSR) for Breast Cancer (BC) Survivors on Salivary Cortisol and IL-6.

Breast cancer survivors (BCS) often experience psychological and physiological symptoms after cancer treatment. Mindfulness-based stress reduction (MBSR), a complementary and alternative therapy, has reduced subjective measures of stress, anxiety, and fatigue among BCS. Little is known, however, about how MBSR affects objective markers of stress, specifically the stress hormone cortisol and the pro-inflammatory cytokine interleukin-6 (IL-6). In the present study, BCS ( N = 322) were randomly assigned to a 6-week MBSR program for BC or usual-care control. Measurements of cortisol, IL-6, symptoms, and quality of life were obtained at orientation and 6 weeks. Cortisol and IL-6 were also measured prior to and after the MBSR(BC) class Weeks 1 and 6. The mean age of participants was 56.6 years and 69.4% were White non-Hispanic. Most had Stage I (33.8%) or II (35.7%) BC, and 35.7% had received chemotherapy and radiation. Cortisol levels were reduced immediately following MBSR(BC) class compared to before the class Weeks 1 and 6 (Wilcoxon-signed rank test; p < .01, d = .52-.56). IL-6 was significantly reduced from pre- to postclass at Week 6 (Wilcoxon-signed rank test; p < .01, d = .21). No differences were observed between the MBSR(BC) and control groups from baseline to Week 6 using linear mixed models. Significant relationships with small effect sizes were observed between IL-6 and both symptoms and quality of life in both groups. Results support the use of MBSR(BC) to reduce salivary cortisol and IL-6 levels in the short term in BCS.

Estructura Interna del Inventario Peruano de Mindfulness y Ecuanimidad / Internal structure of the Mindfulness and Equanimity Peruvian Inventory

Resumen El propósito del presente estudio es examinar la validez de constructo y consistencia interna del Inventario Peruano de Mindfulness y Ecuanimidad. Basado en el análisis factorial y la Teoria de Respuesta al Item (Modelo de Crédito Parcial y el Método de Escalabilidad de Mokken), se examinó la magnitud de los parâmetros y se estimò la varianza de cada uno de los items para contribuir en el constructo general de mindfulness. La muestra del estudio está compuesta por 602 adultos, estudiantes de tres instituciones acadêmicas de educación superior de Lima, Chiclayo y Chimbote en el Perú. Los resultados de estos análisis indican una estructura unidimensional del instrumento, en función a ocho items representados por los atributos de atención, consciencia, aceptación, juicio de valor, y ecuanimidad. Los indicadores de ajuste del modelo de factores oblicuos para los items seleccionados fueron satisfactorios: CEI = .982, RMSEA = .043 (IC90% = .029, .056), SRMR = .048, SB--2 (gl: 35) = 73.415 (p > 0.05).

Abstract The main purpose of this study is to report the construct validity and internal consistency of the Peruvian Inventory of Mindfulness and Equanimity. Based on the factor analysis and the Item response Theory (the Partial Credit Model and the Mokken Scale Analysis), the parameters magnitude was examined, and we estimated the variance of each item of the instrument that contribute to the general construct of mindfulness. The analyses were carried out on a sample of 602 adults, students from three educational institutions at the university level in the cities of Lima, Chiclayo, and Chimbote in Peru. The results of all the analyses performed on this peruvian sample suggest a unidimensional structure of this inventory, based on the eight items selected that include the abilities of attention, consciousness, acceptance, judgment, and equanimity. The goodness of fit index and adjusted goodness of fit index for the oblique factors were satisfactory: CEI = .982, RMSEA = .043 (lC90% = .029, .056), SRMR = .048, SB- -2 (gl: 35) = 73.415 (p > 0.05).

Hacia una integración de mindfulness e inteligencia emocional en psicología y educación / Towards the integration of mindfulness and emotional intelligence in psychology and education

Antecedentes: el presente artículo presenta una revisión empírica de la integración de mindfulness e inteligencia emocional. Mindfulness es un modelo de intervención cognitiva que facilita la toma de consciencia con la experiencia en el momento presente, favoreciendo la autorregulación emocional. Igualmente, la inteligencia emocional ha sido conceptualizada como una constelación de habilidades relacionadas con la percepción, entendimiento y un adecuado manejo de las emociones propias y de los demás. Ambos marcos conceptuales están asociados con un buen sentido de bienestar y desarrollo personal. Estado del arte: se presenta una revisión de la evidencia científica preliminar publicada en la literatura psicológica y de educación, examinando los efectos mediadores de ambos constructos en el proceso de regulación emocional y calidad de vida individual. Conclusiones: los reportes de los estudios evaluados indican que la interacción de mindfulness disposicional e inteligencia emocional ofrece beneficios significativos en los estados de bienestar de las personas. De igual manera, se reportó que la inteligencia emocional es un mediador entre mindfulness e incrementos en las emociones positivas. El propósito del presente artículo de revisión es identificar un modelo integrador en la regulación de la emociones, incluyendo los «ingredientes activos¼ que influyen en los estados de bienestar y la forma en que la práctica de mindfulness contribuye al aumento de las habilidades de la inteligencia emocional.

Background: this article presents an empirical review of the integration of mindfulness and emotional intelligence. Mindfulness is a cognitive intervention model that helps people to develop awareness of their experience in the present moment favoring emotional self-regulation. Similarly, emotional intelligence has been conceptualized as a constellation of abilities related to the perception, understanding and adequate management of emotions within and among people. Both conceptual models are associated with a good sense of well-being and personal development. State of the art: this paper reviews the preliminary scientific evidence published in psychology and education literature, and examines the mediating effects of these two constructs in the process of emotional regulation and quality of life of individuals. Conclusions: the study results indicate that the interaction of mindfulness and emotional intelligence offers important benefits for people's well- being. It was also reported that emotional intelligence acts as mediator between mindfulness and greater positive emotions. The purpose of this review article is to identify a model of integration for emotional regulation that includes «active ingredients¼ to influence well-being and the way in which the practice of mindfulness contributes to increase the abilities of emotional intelligence.

Influence of mindfulness-based stress reduction (MBSR) on telomerase activity in women with breast cancer (BC).

Mindfulness-based stress reduction (MBSR) reduces symptoms of depression, anxiety, and fear of recurrence among breast cancer (BC) survivors. However, the effects of MBSR (BC) on telomere length (TL) and telomerase activity (TA), known markers of cellular aging, psychological stress, and disease risk, are not known. This randomized, wait-listed, controlled study, nested within a larger trial, investigated the effects of MBSR (BC) on TL and TA. BC patients (142) with Stages 0-III cancer who had completed adjuvant treatment with radiation and/or chemotherapy at least 2 weeks prior to enrollment and within 2 years of completion of treatment with lumpectomy and/or mastectomy were randomly assigned to either a 6-week MBSR for BC program or a usual care. Assessments of TA and TL were obtained along with psychological measurements at baseline, 6 weeks, and 12 weeks after completing the MBSR(BC) program. The mean age of 142 participants was 55.3 years; 72% were non-Hispanic White; 78% had Stage I or II cancer; and 36% received both chemotherapy and radiation. In analyses adjusted for baseline TA and psychological status, TA increased steadily over 12 weeks in the MBSR(BC) group (approximately 17%) compared to essentially no increase in the control group (approximately 3%, p < .01). In contrast, no between-group difference was observed for TL (p = .92). These results provide preliminary evidence that MBSR(BC) increases TA in peripheral blood mononuclear cells from BC patients and have implications for understanding how MBSR(BC) may extend cell longevity at the cellular level.

A pilot study evaluating the effect of mindfulness-based stress reduction on psychological status, physical status, salivary cortisol, and interleukin-6 among advanced-stage cancer patients and their caregivers.

PURPOSE: To investigate whether a mindfulness-based stress reduction program for cancer (MBSR-C) improved psychological and physical symptoms, quality of life (QOL), and stress markers among advanced-stage cancer patients and caregivers. DESIGN: A pilot within-subject design was used. METHOD: Patients previously diagnosed with advanced-stage breast, colon, lung, or prostate cancer and on treatment were recruited from the Moffitt Cancer Center and Research Institute. Twenty-six patient-caregiver dyads completed a modified 6-week, self-study MBSR-C program based on the Kabat-Zinn model. Psychological and physical symptoms and QOL were compared pre- and post-MBSR-C sessions. Salivary cortisol and interleukin-6 were assessed pre- and post-MBSR-C session at 1, 3, and 6 weeks. FINDINGS: Following the 6-week MBSR program, patients showed improvements in stress and anxiety (p < .05); caregivers' psychological and QOL also improved but were not statistically significant. Both patients and caregivers had decreases in cortisol at Weeks 1 and 3 (p < .05) but not at Week 6. Similar to cortisol levels at Week 6, salivary interleukin-6 levels were lower overall (before/after an MBSR-C session), compared with Week 1 for patients and caregivers. CONCLUSIONS: MBSR-C may be a beneficial intervention for reducing stress, anxiety, cortisol levels, and symptoms in advanced-stage cancer patients and may also benefit caregivers.

Análisis factorial confirmatorio del inventario multicultural de la expresión de la ira y hostilidad / Confirmatory factor analysis of the multicultural anger expression and hostility inventory

El propósito principal del presente estudio fue verificar la estructura factorial de las dos escalas que componen el Inventario Multicultural de la Expresión de la Ira y Hostilidad desde una perspectiva confirmatoria. Se utilizó el Análisis Factorial Confirmatorio en una muestra de 264 participantes provenientes de una universidad privada de Lima, Perú. El muestreo fue no probabilístico e incluyó estudiantes (25%), personal docente (17.8%) y personal administrativo (57.2%). La confiabilidad del instrumento fue evaluada mediante los modelos congenérico, tau-equivalente y paralelo para cada una de las seis subescalas del instrumento, así como también calculada en base al coeficiente alfa de Cronbach con intervalos de confianza.

The main purpose of this study was to verify the factorial structure of the two scales that make up the Multicultural Inventory of Expression of Anger and Hostility from a confirmatory perspective. We performed the Confirmatory Factor Analysis with a non-probability sample of 264 participants from a private university in Lima, Peru. The sampling included university students (25%), faculty members (17.8%) and administrative staff (57.2%). The reliability of the instrument was evaluated using the congeneric, tau-equivalent and parallel models for each of the six subscales of the instrument, as well as calculated based on Cronbach's alpha coefficient with confidence intervals. Results: Factor analysis performed in the present Peruvian sample identified four dimensions for the Anger Expression Scale (Anger-In, Anger-Out, Anger/Control In, and Anger/Control-Out) and two factors for the Hostility Scale (impulsive reaction to anger; and temperament), which substantially verified the factor structure of previous studies conducted in Latin American samples. The congeneric modelindicates an appropriate fit for each of the subscales of anger and hostility. Based on the results of the Confirmatory Factor Analysis performed in the present study, the factorial structure of both scales of the Multicultural Anger Expression and Hostility Inventory is robust and shows substantial empirical evidence of construction validity and internal consistency of the instrument.

Un método para la comparación de correlaciones basado en intervalos de confianza: aportes a Tejedor et al / A method for comparing correlations based on confidence intervals: contributions to Tejedor et al

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Feasibility of a mindfulness-based stress reduction program for early-stage breast cancer survivors.

PURPOSE: To assess the feasibility of whether mindfulness-based stress reduction (MBSR) has a positive effect on breast cancer survivors' psychological status, psychosocial characteristics, symptoms, and quality of life (QOL) during the critical transition period from end of treatment to resumption of daily activities. DESIGN: Single-group, quasi-experimental, pretest-posttest design. METHOD: A sample of 19 women who completed breast cancer treatment with lumpectomy, radiation, and/or chemotherapy was recruited from the Moffitt Cancer Center and Research Institute, a National Cancer Institute- designated cancer center, and the University of South Florida. The authors assessed the feasibility, compliance, and whether an 8-week MBSR program positively influenced changes in psychological status (fear of recurrence, perceived stress, anxiety, depression), psychosocial characteristics (optimism, social support, spirituality), physical symptoms, and QOL. FINDINGS: Seventeen women (89.5%) completed the study. The mean age was 57 years; the majority of participants (94%) were White. The estimated compliance rate for the program was 67%. Paired t tests indicated significant improvements fear of recurrence, perceived stress, anxiety, depression, and QOL through MBSR participation. CONCLUSIONS: Participants enrolled in the MBSR classes generally were compliant. Significant improvement in psychological status, symptoms, and QOL can be achieved with MBSR use in this population.

Mecanismos neurocognitivos de la terapia basada en Mindfulness / Neurocognitive mechanisms of the Mindfulness based therapy

Presentamos un resumen y una breve historia del creciente campo de Intervenciones Basadas en mindfulness o conciencia plena. En los últimos tiempos, existe un gran interés en este modelo terapéutico para reducir la vulnerabilidad al estrés crónico y distrés emocional. Mindfulness requiere intencionalmente enfocar nuestra atención a las experiencias que ocurren en el momento presente. A medida que la investigación avanza en esta temática, es vital definir cuidadosamente la estructura de mindfulness y comprender mejor sus mecanismos de acción neurocognitiva. Este informe presenta un marco conceptual que enfatiza el papel central de control atencional y mecanismos de sostenibilidad para desarrollar las habilidades de conciencia plena. También, repasamos la estructura de mindfulness y la autorregulación de las emociones; luego describimos brevemente nuestra investigación relacionada con nuestro programa de Reducción del Estrés en Cáncer de Mama basado en Mindfulness (MBSR-AC) en la University of South Florida. Se presenta, a partir de esta premisa, un modelo propuesto que explica nuestros mecanismos cognitivos basados en la lógica del modelo de biocomportamental.

We are presenting an overview and a brief history of the growing field of Mindfulness Based Interventions. There has been a significant interest in this therapeutic model to reduce vulnerability to chronic stress and emotional distress in recent times. Mindfulness requires intentionally bringing our attention to the experiences that occur in the present moment. As the research advances in this line of inquiry, it is vital to carefully define the construct of Mindfulness and better understand its neurocognitive mechanisms of action. This review presents conceptual framework that emphasizes the central role of attentional control and sustainability mechanisms to build mindfulness skills. We also review the construct of Mindfulness and self-regulation of emotions; then describe briefly our research related to our Mindfulness Based-Stress Reduction Breast Cancer (MBSR-BC) program at the University of South Florida. With this premise, we present a model explaining our proposed cognitive mechanisms based on the Logic of the Biobehavioral Model.

La evaluación del malestar emocional percibido: la faceta desatendida de la atención del cáncer / The assessment of the perceived emotional distress: the neglected side of cancer care

The purpose of this research was to present the latest development of the The Perceived Emotional Distress Inventory (PEDI) as a brief 15-item self-report measure intended to be used for the assessment of psychological distress in cancer patients. Factor Analyses of Principal Components with promax rotations were performed with a combined male and female sample of 481 cancer patients at St. Joseph’s hospital Cancer Institute in Tampa, Florida, to provide further evidence of construct validity. The factor structure, internal consistency, and Pearson correlation coefficients of the PEDI are presented in this report. The factor analysis identified three factors comparable to those found in previous samples in USA: The first factor, anxiety/depression; second factor, hopelessness; and third factor, anger expression. Global alpha coefficient of 0.92 for the inventory indicates strong internal consistency. Pearson correlations between the subscales of the instrument is impressive for such a brief measure. This study emphasizes the need for a brief, self-report instrument to assess anger expression, anxiety, depression and hopelessness as components of perceived emotional distress in cancer patients, while explicitly excluding the potentially confounding effects of somatic symptoms commonly associated with cancer treatments. Further research will be needed to provide information about the PEDI’s use in populations other than cancer patients including attempts to replicate these findings in more heterogeneous populations (AU)

El propósito de este estudio fue evaluar la estructura factorial del Inventario de Malestar Emocional Percibido (IDEP), un instrumento de medición del malestar emocional de 15 ítems, en una muestra de 481 pacientes con cáncer que iniciaron sus tratamientos con radioterapia y/o quimioterapia en el Instituto de cancer del hospital St. Joseph’s en la ciudad de Tampa, Florida, USA. Se llevó a cabo un análisis factorial de componentes principales y método de rotación promax con autovalores superiores a 1. El primer factor contiene seven ítems correspondientes a síntomas de ansiedad y depresión. El segundo factor está agrupado por cuatro ítems relacionados con sentimientos de desesperanza, mientras un tercer factor presenta cuatro ítems que manifiestan la expresión de ira. Los resultados obtenidos nos indican que el Inventario de malestar emocional presenta una estructura factorial consistente con el marco conceptual en el cual se basó la construcción del instrumento, El coeficiente alpha de Cronbach para el instrumento total del IDEP es de 0,92, lo cual es significativamente elevado, como también los coeficientes alpha para sus cuatro sub-escalas. Los resultados observados demuestran evidencia empírica acerca de la validez de constructo y la consistencia interna del IDEP. Es necesario un mayor esfuerzo con el propósito de replicar estos mismos resultados en pacientes con otros tipos de diagnostico y en culturas diferentes (AU)

Construct validity of the emotional distress inventory in patients with cancer

The purpose of this study is to evaluate the factor structure of the Emotional Distress Inventory (EDI), a brief 15 item self report measure of emotional distress in a sample of 238 cancer patients. The conceptual framework that guided the development of the EDI, factor structure, internal consistency, and convergent validity are reported. Emotional distress items were developed and administered to cancer patients who initiated chemotherapy and/or radiation treatments at Morton Plant Hospital Cancer Center in Clearwater, Florida, USA. Item responses were examined y Factor Analyses of Principal Components with promax rotations, which yielded three factors. Strong alpha coefficients and correlations between the EDI, HADS and BSI offer impressive evidence of internal consistency and convergent validity. The EDI presents three subscales that assess Anxiety/Depression, Hopelessness, and Anger Expresion as components of emotional distress. We also discuss the important implications of these subscales, particularly the inclusion of anger expression and hopelessness, in the assessment of emotional distress in cancer patients (AU)

El propósito de este estudio es evaluar la estructura factorial del Inventario de Distrés Emocional (EDI), un instrumento de medición del distrés emocional de 15 ítems, en una muestra de 238 pacientes con cáncer que iniciaron sus tratamientos de radioterapia y/o quimioterapia en el Hospital Morton Plant en la ciudad de Clearwater, Florida, USA. Se llevó a cabo un análisis factorial exploratorio mediante componentes principales y método de rotación promax con autovalores superiores a 1. El primer factor está configurado por 7 ítems correspondientes a síntomas de ansiedad y depresión. El segundo factor está agrupado por 4 ítems relacionados con sentimientos de desesperanza, mientras un tercer factor presenta 4 ítems que manifiestan la expresión de ira. Los resultados obtenidos nos indican que el Inventario de Distrés Emocional presenta una estructura factorial consistente con el marco conceptual en el cual se báso la construcción del instrumento, como también un elevado nivel de consistencia interna y validez convergente (AU)