History
Delayed early language development, difficulty segmenting words or recognizing the differences between similar sounds, and a family history of reading disability all indicate a potential learning problem. Reading disorders also correlate highly with attention deficit hyperactivity disorder (ADHD); accordingly, all children with ADHD should be screened for reading problems. [11]
Physical
Specific learning disorders are often not detected until school age. The evaluation may include ADHD testing, developmental evaluation, hearing and vision screenings, and child may ultimately be delayed in the diagnosis of a learning disorders. A multidisciplinary approach is often best in discerning the correct diagnosis and treatment plan.
The pediatrician, child psychiatrist, ophthalmologist, neurologist, psychologist, and developmental pediatrician all play important roles in the diagnosis of children with learning disabilities. Ideally, the clinicians are familiar with various metabolic and genetic syndromes because these conditions can often present with developmental delays and learning difficulties in school.
The pediatrician is best suited to oversee the management of other consultants and correlating the clinical findings. The pediatric psychiatrist is capable of performing a detailed series of tests to evaluating specific reading and learning disorders. The assessment also involves measuring the overall intelligence, reading accuracy, and comprehension. Mood and behavioral disorders are ruled out. The developmental pediatrician can assess spelling age, mathematical age, and visual and auditory perception. Specific testing, such as WISC and GORT testing, can be useful in comparing the child with age-matched peers. Both verbal and performance scales should be assessed to determine spatial organization, visual perception, and associative learning skills.
The pediatric ophthalmologist can assess the visual acuity, visual fields, ocular alignment, convergence and accommodative amplitudes, and sensorimotor evaluation of stereopsis and fusion. If age appropriate, color vision should also be assessed to alert parents and teachers of achromatopsia. Additionally, organic ocular disease, such as amblyopia, opacities of the visual axis, and retinopathies and optic neuropathies can be ruled out by the pediatric ophthalmologist. Refractive errors, if medically indicated, can be corrected with glasses. If fusional disease is present, cortical fusion disorders and motor fusion disorders can be addressed by the pediatric ophthalmologist. If age appropriate, convergence insufficiency should be ruled out.
The pediatric neurologist can assess gross motor skills, deep tendon reflexes, and diseases impacting cerebellar or extrapyramidal pathways.
Causes
Disrupted development of the neuroanatomic regions associated with phonemic segmentation are the primary etiology of reading disorders. Ocular movements and ocular dominance generally do not play any significant role in the development of dyslexia. Patients with dyslexia can demonstrate word reversals, substitutions, and skipping words. These symptoms have been shown to be based in deficiencies within the linguistic centers rather than visual processing disorders. [5] Currently, there is insufficient and conflicting evidence regarding a disruption in the magnocelluluar visual system causing learning disabilities.
Dyslexia involves a difficulty for the child in the areas of reading, writing, and spelling. The learning disability disorders primarily involve problems in phonological skills and word decoding skills. The development of phonological skills ideally occurs in concert with the development of reading skills. However, there are different types of phonological skills and these particular skills are different relative weighting across different languages. A child with dyslexia may learn some phonological skills but remain lacking in others. These skills are then combined with writing (orthographic system). Memory of these two complementary systems of phonological skils and written skills must then be correctly practiced and reproduced. A disruption within this sequence of events is a prinicipal source of the learning disabilities demonstrated. Language development in the oral form plays a critical role in the language development of the written form. Reading and writing require more active learning than speaking alone does. In the process of reading and writing, children must decipher the alphabetic structure, acquire the correct corresponding symbolism, and determine the appropriate meaning. Many patients with dyslexia have a problem with the processing of the sound structure of the language. This is called a phonemic deficit. [13] In more advanced cases, children may also exhibit a second deficit with specific letters, numbers, symbols, or pictures. As such, the child can appear to have or may actually have problems with attention and memory. This can sometimes lead to misdiagnosis of other conditions, such as ADHD. Alternatively, other co-existing diagnoses may result in providers and educators overlooking cases of concomitant dyslexia.
