Acceso usuarios
Catalina Quintero López
, Víctor Daniel Gil Vera, Natalia Gómez Muñoz, Yessica A. Guerra Agudelo, María Fernanda Marín González, María José Álvarez Ríos
El trastorno específico del aprendizaje (SLD, por sus siglas en inglés) está clasificado dentro de las entidades nosológicas del neurodesarrollo, que cursa con dificultades heterogéneas en la adquisición de habilidades lectoras, escritas y matemáticas; persiste en el transcurso de la vida, y está asociado con déficits neurocognitivos. Esta investigación tuvo como objetivo presentar los resultados de una revisión sistemática de 30 publicaciones científicas dirigidas a analizar las características del lenguaje (LG) y de las funciones ejecutivas (EF) en el SLD. La búsqueda de artículos se hizo en Scopus y Web of Science (WoS). La revisión sistemática se desarrolló a través de la metodología PRISMA. Los sujetos con diagnóstico de SLD muestran un desempeño inferior a la media poblacional en las pruebas cognoscitivas que evalúan la memoria de trabajo, que impactan de manera negativa la velocidad de procesamiento y la conciencia fonológica. El bajo rendimiento académico en el SLD se debe al déficit en la maduración cerebral de la corteza prefrontal.
Specific learning disorder (SLD) is classified within the nosological entities of neurodevelopment; it causes heterogeneous alterations in the acquisition of reading, writing and arithmetic skills; it persists throughout life; it is associated with neurocognitive and psychological deficits; language impairment and family history have been considered predisposing antecedents to this disorder; it is considered the main cause of school failure. The diagnostic specificities of SLD have been defined as dysgraphia, dyslexia and dyscalculia. Dyslexia is characterized by problems in the reading process; poor accuracy, hesitations, poor fluency and poor comprehension are evidenced. Dysgraphia is manifested by deficits in written coding; errors in grammatical production, punctuation failures, poor clarity in the structure of ideas, omission/substitution of letters and inability to adequately constitute sentences and paragraphs. Dyscalculia generates difficulty in naming and understanding number sense; change of procedures, failure in arithmetic calculation and counting activities.
This research presents a systematic review of scientific publications aimed at analyzing neurocognitive characteristics of SLD. The search for articles was done in Scopus and Web of Science (WoS) from 2014 to 2021. From a total of 322 articles, 30 were selected that met the defined inclusion criteria; structured and empirical studies, focused on identifying the characteristics of language (LG) and executive functions (EF) in SLD that specified the sample, demographic information, effect size and validity of the psychometric tests provided. The systematic review was developed following the PRISMA 2020 checklist. General metrics were calculated for the selected publications;
quantity by year, authors and countries, Top 10 article-reviews and word cloud. A meta-analysis was performed indicating sample size and type of study, age range of research units, effect size and instruments employed. Qualitative analysis of the selected articles was done by neurocognitive process, EF and LG; the criterion variable SLD was discriminated in the following order; dyslexia, dysgraphia and dyscalculia.
The results show that the systematic literature review allowed us to identify a vast scientific production dedicated to the analysis of diagnostic predictors, risk factors and neurocognitive characteristics of SLD. Publications report that SLD is associated with brain maturation deficits in the frontal and temporal cortex, generating delays in the development of EF, mainly in working memory and in the neurocognitive process of the LG. Subjects diagnosed with SLD show lower performance than the population mean in cognitive tests assessing working memory, negatively impacting processing speed and phonological awareness. SLD generates limitations in academic learning, affects several cognitive domains. The analyzed publications identified that it is associated with deficits in LG and EF. The results of the psychometric instruments used indicate a performance below the population mean in activities measuring processing speed, planning, inhibitory control, working memory and phonological awareness. Deficits in phonological awareness are associated with dysgraphia and dyslexia (semantic confusion, phoneme inversion and replacement, letter omission, spelling deficits and reading decoding deficits. The reported research establishes a link between academic underachievement and deficits in prefrontal cortex brain maturation in SLD. The systematic review was limited to neurocognitive analysis of EF and LG. To establish a comprehensive neurocognitive profile of this disorder, findings from studies focused on other processes should be analyzed. The clinical manifestations of SLD are maintained throughout life. The main limitations of this research refer to the fact that only two neurocognitive processes were addressed; it is recommended for future work to review other processes in order to establish a complete profile of this clinical condition. On the other hand, dyslexia has comorbidity with other neurodevelopmental and behavioral disorders, which could generate variations in the neurocognitive characterizations, which implies a thorough review of the state of the art. In addition, neurocognitive disorders also vary according to language.
