Current Status of Treatments for Dyslexia: Critical Review

Ann W. Alexander, MD; Anne-Marie Slinger-Constant, MD

Disclosures

J Child Neurol. 2004;19(10):744-758. 

In This Article

Diagnosis and Treatment of the Child with Dyslexia

As can be seen from the previous discussion, dyslexia is a complex neurobiologic process that involves a number of different components. The selection of the appropriate treatment approach is not a "one-size-fits-all" situation but rather is based on a detailed, multidisciplinary evaluation, which involves a thorough developmental neurologic assessment, evaluation of gross and fine motor skills, neuropsychoeducational testing with a specific focus on phonologic skills, a speech-language and occupational therapy assessment, and a screening of the child's psychiatric status and the family milieu. All of these assessments play an important role in the selection and management of the treatment phase. As we attempt to identify and treat children at a very early developmental stage, the physician offers expertise in the assessment of these young prereaders, as well as assessing the older child with dyslexia to identify the multiple neurologic components that might be affecting the acquisition of normal reading. Visual schematics, although an oversimplification, can be helpful in the systematic consideration of all of these factors. The following schematics are designed to allow consideration of the components contributing to the development of the phonologic system and the acquisition of reading. They can be helpful in explaining treatment plans to therapists and parents as well.

Children develop their abilities from the bottom up, with the wiring together of sensory stimuli. Those that fire together are more likely to wire together into efficient neural representations.[63] This linkage is enhanced with repetition, and representations are mapped into functional modules in a distinct fine-grained fashion. The more perceptually salient, consistent, frequent, multisensory, and emotionally reinforcing the input, the stronger the map becomes. These factors are helpful to remember when analyzing the child's neurocognitive profile and learning environment. They are also essential for an effective treatment program.

Figure 3 includes the following, from the bottom up:

  • The attention or arousal system, which is essential for the imprinting of sensory inputs

  • Bidirectional arrows, which illustrate the neural networks interacting with each other

  • Stoplights, which have been used to illustrate the neural flow from a representation or a sensory input. A green light represents flow as it should be for optimal, fine-grained mapping, yellow represents compromised flow that results in less precise mapping, and red represents a lack of input from that neural component, requiring the overreliance on other components and the wiring of atypical networks. With impaired inputs, bottlenecks or "roadblocks" to learning occur. The more distinct components of sensory input or cortical representations must be relied on more frequently for skill acquisition; the less distinct are ignored. It is hypothesized that a type of "Matthew effect" occurs.the strong become stronger, and the weak become weaker.[64,65] Thus, children with phonologic weakness do not choose to engage in activities that use this system. They must be immersed in it in an explicit and systematic fashion, as noted above, to develop the necessary neural networks. Therefore, an analytic approach as to which pathways are well developed and which are not is essential for the planning of effective intervention strategies.

  • The working memory block, which represents the time-sensitive "slave" systems of the central executive system that are responsible for retrieving, holding, and manipulating information for processing. It has a different developmental timetable than that of executive function, which is represented as a higher level of processing on the schematic.[66] The role of executive function as strategist, top-down processor, and controller of attention to tasks and regulator of motor intention is illustrated by broken lines to signify that it is not as fully developed in the young child. Deficits in these executive functions are being considered as a possible third core deficit in dyslexia after the phonologic and rapid naming core deficits (Berninger VW, personal communication, 2003).

The development of the phonologic system.a visual schematic illustrating the neural substrates and networks needed for the optimal development of the phonologic system. The stoplights serve to illustrate whether the neural substrates allow for efficient networking ( green ), as is shown here. The stoplights can be used to explain treatment plans, illustrating when substrates are suboptimal, resulting in a "bottleneck" ( yellow ), or are nonexistent, requiring a "detour."

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