Polysomnographic parameters associated with cognitive function in patients with major depression and insomnia.

OBJECTIVE: To examine whether objective sleep parameters are associated with cognitive function (CF) in patients with major depressive disorder (MDD) with chronic insomnia (CI) and whether the severity of these disorders is related to CF. METHOD: Thirty patients with MDD with CI attending a tertiary care institution underwent two consecutive nights of polysomnographic (PSG) recording and a battery of neuropsychological tests, which included episodic memory, sustained attention, working memory, and executive function. The severity of MDD and CI was assessed by clinical scales. We examined the relationship between PSG parameters and CF, as well as whether the severity of the disorders is related to CF. RESULTS: Linear regression analysis revealed that total sleep time (TST) was positively associated with higher learning and recall of episodic memory, as well as better attention. Slow-wave sleep (SWS) showed a positive association with better working memory. Furthermore, wake after sleep onset (WASO) was negatively associated with episodic memory and lower attention. No significant relationships were found between the severity of MDD or CI with CF. CONCLUSION: Both sleep duration and depth are positively associated with several aspects of CF in patients with MDD with CI. Conversely, a lack of sleep maintenance is negatively related to CF in these patients. These findings could help identify modifiable therapeutic targets to reduce CF impairment.

Reliability and factorial analysis of the Dysfunctional Beliefs and Attitudes Scale About Sleep in Mexican population. / Confiabilidad y análisis factorial de la Escala de Creencias y Actitudes Disfuncionales acerca del Dormir en población Mexicana.

BACKGROUND: The behaviors and thoughts that individuals have about sleep have an influence on the persistence or improvement of insomnia. The Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS) was developed with the aim to measure them. OBJECTIVE: To assess the reliability and factorial composition of the Spanish version of the 16-item DBAS. METHOD: A cross-sectional design of two independent samples was used: one group with insomnia and a control group without it. We estimated the DBAS internal consistency coefficient and compared scores between groups; we also performed an exploratory factorial analysis of the scale. RESULTS: 166 patients with insomnia and 115 control individuals filled-out the DBAS. The scale showed a satisfactory reliability coefficient (with a Cronbach's alpha of 0.85) and we found it was composed by three factors which explained 49.2% of the variance. Insomnia patients had significantly higher scores on the total DBAS score and in each one of the 3 factors. CONCLUSIONS: The Spanish version of the 16-item DBAS is a reliable instrument to measure several behaviors and beliefs about sleep in insomnia patients.

INTRODUCCIÓN: Los comportamientos y pensamientos que un individuo tiene acerca del sueño tienen influencia en la persistencia o la resolución del insomnio. Con el fin de evaluarlos se desarrolló la Escala de Actitudes y Creencias Disfuncionales acerca del Dormir (DBAS, Dysfunctional Beliefs and Attitudes about Sleep Scale). OBJETIVO: Evaluar la confiabilidad y la composición factorial de la versión en español de 16 reactivos de la DBAS. MÉTODO: Se utilizó un diseño transversal de dos muestras independientes: un grupo clínico con insomnio y un grupo control. Se estimó el coeficiente de consistencia interna, se hizo el análisis factorial exploratorio de la escala y se compararon las puntuaciones entre los grupos. RESULTADOS: Se incluyeron 166 pacientes con insomnio y 115 individuos control que completaron la DBAS. La escala mostró un coeficiente de confiabilidad satisfactorio (con un alfa de Cronbach de 0.85) y una estructura de tres factores que explicaron el 49.2% de la varianza. Los pacientes con insomnio tuvieron calificaciones significativamente mayores que los sujetos control en la puntuación total y en los tres factores. CONCLUSIONES: La versión en español de la DBAS de 16 reactivos es un instrumento confiable para evaluar algunos comportamientos y creencias relacionadas con el dormir que se presentan en el insomnio.