Learning disorders (formerly academic skills disorders)
Learning Disorders (formerly Academic Skills Disorders)
The section on Learning Disorders includes Reading Disorder, Mathematics Disorder, Disorder of Written Expression, and Learning Disorder Not Otherwise Specified.
Diagnostic Features
Learning Disorders are diagnosed when the individual's achievement on individually administered, standardized tests in reading, mathematics, or written expression is substantially below that expected for age, schooling, and level of intelligence. The learning problems significantly interfere with academic achievement or activities of daily living that require reading, mathematical, or writing skills. A variety of statistical approaches can be used to establish that a discrepancy is significant. Substantially below is usually defined as a discrepancy of more than 2 standard deviations between achievement and IQ. A smaller discrepancy between achievement and IQ (i.e., between 1 and 2 standard deviations) is sometimes used, especially in cases where an individual's performance on an IQ test may have been compromised by an associated disorder in cognitive processing, a comorbid mental disorder or general medical condition, or the individual's ethnic or cultural background. If a sensory deficit is present, the learning difficulties must be in excess of those usually associated with the deficit. Learning Disorders may persist into adulthood.
Associated Features and Disorders
Demoralization, low self-esteem, and deficits in social skills may be associated with Learning Disorders. The school drop-out rate for children or adolescents with Learning Disorders is reported at nearly 40% (or approximately 1.5 times the average). Adults with Learning Disorders may have significant difficulties in employment or social adjustment. Many individuals (10%-25%) with Conduct Disorder, Oppositional Defiant Disorder, Attention-Deficit/Hyperactivity Disorder, Major Depressive Disorder, or Dysthymic Disorder also have Learning Disorders. There is evidence that developmental delays in language may occur in association with Learning Disorders (particularly Reading Disorder), although these delays may not be sufficiently severe to warrant the separate diagnosis of a Communication Disorder. Learning Disorders may also be associated with a higher rate of Developmental Coordination Disorder.
There may be underlying abnormalities in cognitive processing (e.g., deficits in visual perception, linguistic processes, attention, or memory, or a combination of these) that often precede or are associated with Learning Disorders. Standardized tests to measure these processes are generally less reliable and valid than other psychoeducational tests. Although genetic predisposition, perinatal injury, and various neurological or other general medical conditions may be associated with the development of Learning Disorders, the presence of such conditions does not invariably predict an eventual Learning Disorder, and there are many individuals with Learning Disorders who have no such history. Learning Disorders are, however, frequently found in association with a variety of general medical conditions (e.g., lead poisoning, fetal alcohol syndrome, or fragile X syndrome).
Specific Culture Features
Care should be taken to ensure that intelligence testing procedures reflect adequate attention to the individual's ethnic or cultural background. This is usually accomplished by using tests in which the individual's relevant characteristics are represented in the standardization sample of the test or by employing an examiner who is familiar with aspects of the individual's ethnic or cultural background. Individualized testing is always required to make the diagnosis of a Learning Disorder.
Prevalence
Estimates of the prevalence of Learning Disorders range from 2% to 10% depending on the nature of ascertainment and the definitions applied. Approximately 5% of students in public schools in the United States are identified as having a Learning Disorder.
Differential Diagnosis
Learning Disorders must be differentiated from normal variations in academic attainment and from scholastic difficulties due to lack of opportunity, poor teaching, or cultural factors. Inadequate schooling can result in poor performance on standardized achievement tests. Children from ethnic or cultural backgrounds different from the prevailing school culture or in which English is not the primary language and children who have attended class in schools where teaching has been inadequate may score poorly on achievement tests. Children from these same backgrounds may also be at greater risk for absenteeism due to more frequent illnesses or impoverished or chaotic living environments.
Impaired vision or hearing may affect learning ability and should be investigated through audiometric or visual screening tests. A Learning Disorder may be diagnosed in the presence of such sensory deficits only if the learning difficulties are in excess of those usually associated with these deficits. Accompanying neurological or other general medical conditions should be coded on Axis III.
In Mental Retardation, learning difficulties are commensurate with general impairment in intellectual functioning. However, in some cases of Mild Mental Retardation, the level of achievement in reading, mathematics, or written expression is significantly below expected levels given the person's schooling and severity of Mental Retardation. In such cases, the additional diagnosis of the appropriate Learning Disorder should be made.
An additional Learning Disorder diagnosis should be made in the context of a Pervasive Developmental Disorder only when academic impairment is significantly below expected levels given the individual's intellectual functioning and schooling. In individuals with Communication Disorders, intellectual functioning may have to be assessed using standardized measures of nonverbal intellectual capacity. In cases in which academic achievement is significantly below this measured capacity, the appropriate Learning Disorder should be diagnosed.
Mathematics Disorder and Disorder of Written Expression most commonly occur in combination with Reading Disorder. When criteria are met for more than one Learning Disorder, all should be diagnosed.