Neurobiology of Specific Learning Disorder [Neurobiology of SLD]

Описание: Neurobiology of Specific Learning Disorder [Neurobiology of SLD]

Learning disabilities are a heterogeneous group of disorders characterized by failure to acquire, retrieve, and use information competently. These disorders have a multifactorial aetiology and are most common and severe in children, especially when comorbid with other chronic health conditions

The most prevalent view of SLDs among researchers and clinicians is that these are specific in nature. For instance, children with dyslexia display severe deficits in reading, whereas children with dyscalculia present with arithmetic deficits. Moreover, these specific behavioral profiles are thought to arise from isolated core deficits shared among children with the same label.

Studies of SLDs are guided by evidence from case studies of adult neuropsychological patients, where lesions to single brain regions have been associated with specific deficits in cognitive processing within single domains

Extraordinary progress in functional brain imaging, primarily advances in functional magnetic resonance imaging, now allows scientists to understand the neural systems serving reading and how these systems differ in dyslexic readers. Scientists now speak of the neural signature of dyslexia, a singular achievement that for the first time has made what was previously a hidden disability, now visible. Paralleling this achievement in understanding the neurobiology of dyslexia, progress in the identification and treatment of dyslexia now offers the hope of identifying children at risk for dyslexia at a very young age and providing evidence-based, effective interventions. Despite these advances, for many dyslexic readers, becoming a skilled, automatic reader remains elusive, in great part because though children with dyslexia can be taught to decode words, teaching children to read fluently and automatically represents the next frontier in research on dyslexia

Recent findings now present a competing view: other cognitive processes are involved in reading, particularly attentional mechanisms, and that disruption of these attentional mechanisms play a causal role in reading difficulties. Recognition of the role of attentional mechanisms in reading now offer potentially new strategies for interventions in dyslexia. In particular, the use of pharmacotherapeutic agents affecting attentional mechanisms not only may provide a window into the neurochemical mechanisms underlying dyslexia but also may offer a potential adjunct treatment for teaching dyslexic readers to read fluently and automatically. Preliminary studies suggest that agents traditionally used to treat disorders of attention, particularly attention-deficit/hyperactivity disorder, may prove to be an effective adjunct to improving reading in dyslexic students.

Learning disabilities are the product of neurological damage which occurs during fetal development. The malformations produced are unique to each individual and do not resemble acquired neurological damage. Consequently, models of developmental disorders must be developed independently and cannot be based on acquired adult aphasia or dyslexia literature. Neurological conditions of adults with developmental disorders are difficult to interpret since aberrations that occur early during fetal development can have a cascading effect, disrupting neural organization in other brain regions. An appreciation of basic concepts of brain development suggests treatment interventions that will modify neurophysiological functioning.

Neurological conditions of adults with developmental disorders are difficult to interpret since aberrations that occur early during fetal development can have a cascading effect, disrupting neural organization in other brain regions