ABSTRACT
Learning disorders (LDs) are diagnosed in children whose academic skills of reading, writing or mathematics are impaired and lagging according to their age, schooling and intelligence. Children with LDs experience substantial working memory (WM) deficits, even more pronounced if more than one of the academic skills is affected. We compared the task-related electroencephalogram (EEG) power spectral density of children with LDs (n = 23) with a control group of children with good academic achievement (n = 22), during the performance of a WM task. sLoreta was used to estimate the current distribution at the sources, and 18 brain regions of interest (ROIs) were chosen with an extended version of the eigenvector centrality mapping technique. In this way, we lessened some drawbacks of the traditional EEG at the sensor space by an analysis at the brain-sources level over data-driven selected ROIs. Results: The LD group showed fewer correct responses in the WM task, an overall slower EEG with more delta and theta activity, and less high-frequency gamma activity in posterior areas. We explain these EEG patterns in LD children as indices of an inefficient neural resource management related with a delay in neural maturation.
ABSTRACT
Introducción: Se considera la reserva cognitiva (RC) como la optimización de los recursos cerebrales al emplear redes neuronales y estrategias cognitivas alternativas. Se piensa que la RC es una explicación plausible a un mecanismo potencial que permite al cerebro compensar deficiencias, ya sean causadas por el deterioro cerebral o por el declive funcional. Objetivo: Analizar la información de la literatura científica acerca de los efectos de la RC sobre variables clínicas y cognitivas en pacientes con diversas enfermedades distintas a las demencias. Desarrollo: Se realizó una búsqueda sistemática en las bases PubMed/Medline y ScienceDirect de artículos que evaluaran la influencia de la RC sobre variables clínicas y cognitivas en pacientes con enfermedades distintas a las demencias, incluyendo estudios empíricos con diseño longitudinal/transversal y observacional/cuasiexperimental. Se incluyeron 107 artículos. Resultados: Mayores niveles de RC se relacionan con un menor deterioro cognitivo en una gran variedad de trastornos y con una mejor recuperación en pacientes con enfermedad neurológica, psiquiátrica, infecciosa, cáncer, etc. También hay evidencia sobre el papel de la RC como factor protector para el retraso en el desarrollo de enfermedades neurológicas, neuropsiquiátricas, infecciosas, etc. Limitaciones: Podría existir más bibliografía, pues solo exploramos 2 bases. Conclusión: Una aproximación a la RC podría estar constituida por un conjunto de variables (cognitivas, demográficas, físicas, etc.) que parecen influir de manera importante sobre aspectos cognitivos, clínicos y funcionales de diversas enfermedades. Se subraya la necesidad de investigar a profundidad el papel de la RC en el proceso de recuperación y como factor protector en diferentes dolencias
Introduction: Cognitive reserve (CR) is considered as an optimisation of brain resources by using alternative neural networks and cognitive strategies. It is suggested that CR is a plausible explanation of a potential mechanism that allows the brain to compensate deficiencies caused either by brain damage or functional decline. Objective: To analyse the information from scientific literature about the effects of CR on clinical and cognitive variables of patients affected by disorders other than dementia. Development: A systematic search was conducted in the PubMed/Medline and ScienceDirect databases. A review was performed on articles that assessed the influence of CR in clinical and cognitive variables associated with disorders other than dementia. Empirical, longitudinal/transactional, and observational/quasi-experimental design studies were considered. The study finally included 107 research papers that fulfilled the established criteria. Results: Higher CR levels were associated with lower cognitive impairment in a wide variety of disorders, as well as with a better recovery on neurological, psychiatric or infectious conditions. Moreover, there is evidence on the CR role as a protective factor that could delay the development of neurological, neuropsychiatric, or infectious disorders. Limitations: As only 2 databases were searched, there may be more literature references on CR. Conclusion: CR proxies constitute a set of variables (cognitive, demographic, physical, etc.) that may have a significant influence on cognitive, clinical and functional aspects of different disorders. The need to conduct more research about the role of CR in the recovery process and as a protective factor in different disorders is highlighted
