Legasthenia: A Review of the Neuropsychological Evidence
Abstract
Legasthenia, also known as developmental dyslexia, is a disorder of reading, writing, and spelling skills that affects a person’s ability to learn and process language. This review examines the current state of the scientific literature on legasthenia, with a focus on neuropsychological evidence. The review provides an overview of the major neuropsychological deficits associated with the disorder, empirical evidence of the neuropsychological basis of legasthenia, and potential implications for diagnosis and intervention.
Introduction
Legasthenia, also known as developmental dyslexia, is a disorder characterized by difficulty in reading, writing, and spelling skills. It is estimated that between 5 and 10 percent of the world’s population has some form of legasthenia (Grigorenko, 2017). Research on legasthenia has grown significantly in recent years, with a particular focus on its neuropsychological basis. This review provides an overview of the existing research on legasthenia, with a focus on neuropsychological evidence.
Neuropsychological Deficits in Legasthenia
Legasthenia is associated with difficulties in a variety of cognitive and linguistic skills. These include deficits in oral language, phonological awareness, phonological memory, orthographic processing, and rapid automatized naming (Grigorenko, 2017). Oral language deficits can manifest in difficulty producing and comprehending spoken language, while phonological deficits can lead to errors in pronunciation and difficulty with phoneme manipulation. Orthographic deficits can lead to difficulty in processing written words, while rapid automatized naming deficits can lead to difficulty in quickly naming objects.
Neuropsychological Basis of Legasthenia
The neuropsychological deficits associated with legasthenia are thought to be related to dysfunction in specific brain areas. Neuroimaging studies have shown that people with legasthenia have decreased activity in the left temporoparietal cortex, left inferior frontal gyrus, and left cerebellum (Grigorenko, 2017). These brain areas are involved in language processing, phonological processing, and motor control, respectively. In addition, neuropsychological studies have found that people with legasthenia have difficulty with tasks that require the integration of multiple cognitive processes, such as reading comprehension and writing (Grigorenko, 2017). These deficits suggest that legasthenia is associated with dysfunction in multiple brain areas.
Implications for Diagnosis and Intervention
The neuropsychological evidence for legasthenia suggests that it is a disorder with a neurobiological basis, and that it should be diagnosed and treated accordingly. Neuropsychological assessments can provide important information about the areas of cognitive functioning that are affected by legasthenia, and can help to identify appropriate interventions. Interventions should focus on teaching strategies that address the underlying cognitive deficits, such as phonemic awareness and orthographic processing. Furthermore, research suggests that interventions should target multiple areas of functioning, such as language, reading, and writing (Grigorenko, 2017).
Conclusion
Legasthenia is a disorder characterized by deficits in reading, writing, and spelling skills. Research has shown that this disorder is associated with dysfunction in specific brain areas, as well as deficits in multiple cognitive and linguistic skills. Neuropsychological assessments can provide important information about the cognitive deficits associated with legasthenia, and can be used to guide diagnosis and intervention.
References
Grigorenko, E. L. (2017). Dyslexia: A Comprehensive and International Approach. New York, NY: Oxford University Press.