Even though there has considerable progress in the scientific understanding and medical treatments for dyslexia over the past five years, a study published Online First in The Lancet states that a significant amount of research still needs to be conducted in order to completely understand the causes of the disorder and to improve the lives of children affected by it.
Usually dyslexia is not diagnosed until after children experience serious difficulties in school, however, at this time it is harder for these children to master new skills. According to the researchers, late diagnosis could prevent children with the disorder from achieving the best outcomes.
Robin Peterson and Bruce Pennington from the University of Denver, USA, said:
"Professionals should not wait until children are formally diagnosed with dyslexia or experience repeated failures before implementation of reading treatment, because remediation is less effective than early intervention."
Approximately 7% of individuals are dyslexic, and boys are around two times more likely to have the disorder than girls. Researchers originally thought that the disorder involved problems with visual processing, although increasing evidence indicates that the underlying deficit involved phonological impairment (difficulty with how sounds in language are heard and mapped onto letters).
The researchers explain:
"Like all behaviorally defined disorders, the cause of dyslexia us multifactorial and is associated with multiple genes and environmental risk factors."
Researchers have recently identified 6 genes that contribute to dyslexia although they are still unsure as to how these genes and other possible genetic determinants might contribute to the disorder or what role the environment plays in the cause of dyslexia.
Further studies are required in order to:
- Identify more genes that may contribute to the disorder.
- Analyze the effects of environmental risk factors, such as the language and pre-literacy environments that parents provide for their children.
- Identify which gene locations are share and not shared with comorbid disorders, including attention deficit hyperactivity disorder (ADHD).
"We still need to learn more about the nature of phonological deficit and how this problem interacts with other linguistic and non-linguistic risk factors, the developmental course of neural abnormalities and how these predict treatment response, and which environmental risk factors contribute to the development of poor reading and whether these are the same across demographic groups."
In addition treatment issues also need to be addressed. The researchers said:
"Brain-imaging studies have shown that effective intervention seems to promote normalization of activity in the left hemisphere reading and language network that has shown reduced activity in dyslexia."
The team highlight that co-existing conditions, such as ADHD, speed sound disorder, and language impairment are likely to be apparent much sooner, and could be used to help predict a child's risk of subsequent reading difficulties.
"Many effective treatments are low cost, which further draws attention to the importance of early identification, prevention, and treatment of dyslexia for public health."
Written By Grace Rattue