Learning Disorders

Learning Disorders
Type of psychology: Psychopathology
Field of study: Childhood and adolescent disorders
Learning disorders (LD) comprise the disorders usually first diagnosed in infancy,
childhood, or adolescence. Because the condition affects the academic progress of approximately
5 percent of all public school students in the United States, it has attracted
the attention of clinicians, educators, and researchers from varied disciplines. Substantial
progress has been made in the assessment and diagnosis of learning disorders
but questions regarding etiology, course, and treatment of the disorder continue to
challenge investigators.
Key concepts
• disorder of written expression
• dyslexia
• learning disabilities
• learning disorder not otherwise specified
• mathematics disorder
• phonological processing
• reading disorder
Learning disorders (LD) is a general term for clinical conditions that meet
three diagnostic criteria: An individual’s achievement in an academic domain
(such as reading) is substantially below that expected given his or her
age, schooling, and level of intelligence; the learning disturbance interferes
significantly with academic achievement or activities of daily living that require
specific academic skills; and if a sensory deficit (such as blindness or
deafness) is present, the learning difficulties are in excess of those usually associated
with it. The American Psychiatric Association’s Diagnostic and Statistical
Manual of Mental Disorders: DSM-IV-TR (rev. 4th ed., 2000) specifies four
subcategories of learning disorders: Reading Disorder, Mathematics Disorder,
Disorder of Written Expression, and Learning Disorder Not Otherwise
Specified (NOS). The criteria for the first three specific learning disorders
are the same except for the academic domain affected by the disorder. The
fourth subcategory is reserved for disorders involving learning the academic
skills that do not meet the criteria for any specific learning disorder.
Included are problems in all three academic domains (reading, mathematics,
written expression) that together significantly interfere with academic
achievement even though academic achievement as measured on standardized
tests does not fall substantially below what is expected given the individual’s
chronological age, intelligence quotient (IQ), or age-appropriate education.
A variety of statistical approaches are used to produce an operational definition
of “substantially below” academic achievement. Despite some controversy
about its appropriateness, the most frequently used approach defines “substantially below” as a discrepancy between achievement and IQ of
more than two standard deviations (SD). In cases where an individual’s performance
on an IQ test may have been compromised by an associated disorder
in linguistic or information processing, an associated mental disorder, a
general medical condition, or the individual’s ethnic or cultural background,
a smaller discrepancy (between one and two SDs) may be acceptable.
Differential diagnosis involves differentiating learning disorders from
normal variations in academic achievement, scholastic difficulties due to
lack of opportunity, poor teaching, or cultural factors, and learning difficulties
associated with a sensory deficit. In cases of pervasive developmental disorder
or mild mental retardation, an additional diagnosis of learning disorder
is given if the individual’s academic achievement is substantially below
the expected level given the individual’s schooling and intelligence.
The term “learning disorders” was first applied to a clinical condition
meeting these three criteria in the Diagnostic and Statistical Manual of Mental
Disorders (4th ed., DSM-IV), published in 1994. Earlier editions of the DSM
used other labels such as “learning disturbance,” a subcategory within special
symptom reactions in DSM-II (1968). In DSM-III (1980) and DSM-III-R
(1987), the condition was labeled “Academic Skills Disorders” and listed under
“Specific Developmental Disorders”; furthermore, the diagnosis was
based only on “substantially below” academic achievement, and the disorder
was classified as an Axis II rather than an Axis I or clinical condition. The
LD condition is also known by names other than those used in the psychiatric
nomenclature, most frequently as “learning disabilities,” which is defined
as a disorder in one or more of the basic psychological processes involved
in understanding or in using spoken or written language, which may
manifest itself in an imperfect ability to listen, think, speak, read, write,
spell, or do mathematical calculations in children whose learning problems
are not primarily the result of visual, hearing, or motor handicaps, mental
retardation, emotional disturbance, or environmental, cultural, or economic
disadvantage. Learning disabilities is the term used in P.L. 94-142,
the Education for All Handicapped Children Act of 1975, and in P.L. 101-
476, the Individuals with Disabilities Education Act. Specific learning disorders
are also referred to by other names, such as dyslexia (Reading Disorder),
dyscalculia (Mathematics Disorder), or dysgraphia (Disorder of
Written Expression). Empirical evidence about prevalence, etiology, course
of the disorder, and intervention comes mainly from subjects identified as
having dyslexia or learning disabilities.