Learning Disorders
Learning disorders in a child or adolescent are characterized by academic underachievement in reading, written expression, or mathematics in comparison with the overall intellectual ability of the child. Children with learning disorders often find it difficult to keep up with their peers in certain academic subjects, whereas they excel in others. Learning disorders affect at least 5 percent of school-age children. This represents approximately half of all public school children who receive special education services in the United States. In 1975, Public Law 94-142 (the Education for All Handicapped Children Act) mandated all states to provide free and appropriate educational services to all children. Since that time, the number of children identified with learning disorders has increased, and a variety of definitions of learning disabilities has arisen. The term learning disorders, formally referred to as academic skills disorders, was introduced by the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). To meet the criteria for a diagnosis of learning disorder, a child’s achievement in that particular learning area must be significantly lower than expected and the learning problems must interfere with academic achievement or activities of daily living.
The most recent revised version of the DSM-IV (DSM-IV-TR) includes four diagnostic categories of learning disorders: reading disorder, mathematics disorder, disorder of written expression, and learning disorder not otherwise specified. Children with a learning disorder, such as reading disorder, for example, can be identified in two different ways: children who read poorly compared with most other children of the same age and children whose achievement in reading is significantly lower than their overall intelligence quotient (IQ) would predict. DSM-IV-TR criteria for learning disorders require a substantial IQ-achievement discrepancy and significantly poor achievement in reading compared with that of most children of the same age. Research studies have led to questions regarding inclusion of an IQ-achievement discrepancy component in the definition of a learning disorder because current data suggest that most children with reading disorders, for example, have similar deficits in phonological processing skills, regardless of their IQ. That is, most children with reading disorders have trouble with word recognition and “sounding out” words because they cannot understand and use phonemes, the smaller bits of words that are associated with particular sounds.
READING DISORDER
Reading disorders are present in approximately 75 percent of children and adolescents with learning disorders. Students who have learning problems in other academic areas most commonly experience difficulties with reading as well.
Reading disorder is defined as reading achievement below the expected level for a child’s age, education, and intelligence, with the impairment interfering significantly with academic success or the daily activities that involve reading. According to DSM-IV-TR, if a neurological condition or sensory disturbance is present, the reading disability exhibited exceeds that usually associated with the other condition.
Reading disorder is characterized by an impaired ability to recognize words, slow and inaccurate reading, and poor comprehension. In addition, children with attention-deficit/hyperactivity disorder (ADHD) are at high risk for reading disorder. Historically, many different labels have been used to describe reading disabilities, including word blindness, reading backward, learning disability, alexia, and developmental word blindness. The term developmental alexia was accepted and defined as a developmental deficit in the recognition of printed symbols. This term was simplified by adopting the term dyslexia in the 1960s. Dyslexia was used extensively for many years to describe a reading disability syndrome that often included speech and language deficits and right-left confusion.
Epidemiology
An estimated 4 percent of school-age children in the United States have reading disorder; prevalence studies find rates ranging between 2 and 8 percent. Three to four times as many boys as girls are reported to have reading disability in clinically referred samples. No clear gender differential is seen among adults who report reading difficulties.
Comorbidity
Children with reading disorder are at higher-than-average risk for attentional problems, disruptive behavior disorders, and depressive disorders, particularly older children and adolescents. Data suggest that up to 25 percent of children with reading disorder also have ADHD. Conversely, it is estimated that between 15 and 30 percent of children diagnosed with ADHD have a learning disorder. Children with reading disorders experience higher levels of anxiety symptoms than children without learning disorders. Furthermore, children with reading disorders tend to be at increased risk for problematic peer relationships and have less skills responding to subtle social cues.
Etiology
Data from cognitive, neuroimaging, and genetic studies indicate that reading disorder is most accurately described as a
neurobiological disorder with a genetic origin. It is believed to reflect a deficiency in processing sounds of spoken language. That is, children who struggle with reading have a deficit in phonological processing skills. These children cannot identify effectively the parts of words that denote specific sounds, which leads to grave difficulty in recognizing and sounding out words. Children with reading disorders are slower than average in naming letters and numbers, even when controlling for IQ. Thus, the core deficit for children with reading disorders lies within the domain of language use.
neurobiological disorder with a genetic origin. It is believed to reflect a deficiency in processing sounds of spoken language. That is, children who struggle with reading have a deficit in phonological processing skills. These children cannot identify effectively the parts of words that denote specific sounds, which leads to grave difficulty in recognizing and sounding out words. Children with reading disorders are slower than average in naming letters and numbers, even when controlling for IQ. Thus, the core deficit for children with reading disorders lies within the domain of language use.
Complications during pregnancy and prenatal and perinatal difficulties are common in the histories of children with reading disorder. Extremely low birthweight and severely premature children are at higher risk for reading disorder and other learning disorders than children who are born full term and have normal birthweight. A recent study reviewed the relationship between critical periods for brain growth and babies born significantly preterm. Children who are born very preterm who attend mainstream schools have been noted to be at increased risk of minor motor, behavioral, and learning disorders. These appear to be associated with postnatal growth, particularly of the head. Although intrauterine growth retardation may play a role in compromised intellectual capacity, interventions that aim to improve motor ability and potentially learning disorders should focus on optimal nutrition and care postnatally.
Diagnosis
Reading disorder is diagnosed when a child’s reading achievement is significantly below that expected of a child of the same age and intellectual capacity (Table 35-1). Characteristic diagnostic features include difficulty recalling, evoking, and sequencing printed letters and words; processing sophisticated grammatical constructions; and making inferences. Clinically, a child may be first identified with a reading disorder after becoming demoralized or exhibiting symptoms of depression related to being unable to succeed in school. School failure and ensuing poor self-esteem can exacerbate the problems as the child becomes more consumed with a sense of failure and spends less time focusing on academic work. Students suspected of having reading disorders are entitled to an educational evaluation through the school district to determine eligibility for special education services. Special education classification, however, is not uniform across states or regions, and students with identical reading difficulties may be eligible for services in one region but ineligible in another. In some cases, an evaluation is requested on the basis of disruptive behavioral problems that occur in conjunction with the reading disorder.
Table 35-1 DSM-IV-TR Diagnostic Criteria for Reading Disorder | ||||||||||
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Clinical Features
Children who have reading disorder can usually be identified by the age of 7 years (second grade). Reading difficulty may be apparent among students in classrooms where reading skills are expected as early as the first grade. Children can sometimes compensate for reading disorder in the early elementary grades by the use of memory and inference, particularly when the disorder is associated with high intelligence. In such instances, the disorder may not be apparent until age 9 years (fourth grade) or later. Children with reading disorder make many errors in their oral reading. The errors are characterized by omissions, additions, and distortions of words. Such children have difficulty in distinguishing between printed letter characters and sizes, especially those that differ only in spatial orientation and length of line. The problems in managing printed or written language can pertain to individual letters, sentences, and even a page. The child’s reading speed is slow, often with minimal comprehension. Most children with reading disorder have an age-appropriate ability to copy from a written or printed text, but nearly all spell poorly.
Associated problems include language difficulties, exhibited often as impaired sound discrimination and difficulty in sequencing words properly. A child with disorders may start a word either in the middle or at the end of a printed or written sentence. At times, because of a poorly established left-right tracking sequence, such children transpose letters to be read. Failures in both memory recall and sustained elicitation result in poor recall of letter names and sounds.
Most children with reading disorder dislike and avoid reading and writing. Their anxiety is heightened when they are confronted with demands that involve printed language. Many children with the disorder who do not receive remedial education have a sense of shame and humiliation because of their continuing failure and subsequent frustration. These feelings grow more intense with time. Older children tend to be angry and depressed and exhibit poor self-esteem.
Pathology and Laboratory Examination
No specific physical signs or laboratory measures are helpful in the diagnosis of reading disorder. Psychoeducational testing, however, is critical in determining this diagnosis. The diagnosis of reading disorder is made after collecting data from a standardized intelligence test and an educational assessment of achievement. The diagnostic battery generally includes a standardized spelling test, written composition, processing and use of oral language, design copying, and judgment of the adequacy of pencil use. The reading subtests of the Woodcock-Johnson Psycho-Educational Battery-Revised and the Peabody Individual Achievement Test-Revised are useful in identifying reading disability. A screening projective battery may include human-figure drawings, picture-story tests, and sentence completion. The evaluation should also include systematic observation of behavioral variables.
Course and Prognosis
Many children with reading disorder gain some knowledge of printed language during their first 2 years in grade school, even without any remedial assistance. By the end of the first grade, many children with reading disorder, in fact, have learned how to read a few words; however, by the time a child with a reading disorder reaches the third grade, keeping up with classmates is exceedingly difficult without remedial educational intervention. In the best circumstances, a child is recognized as being at risk for a reading disorder during the kindergarten year or early in the first grade. When remediation is instituted early, in milder cases, it is no longer necessary by the end of the first or second grade. In severe cases and depending on the pattern of deficits and strengths, remediation may be continued into the middle and high school years.
Differential Diagnosis
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