Overview of Learning Disorders
Learning disorders are conditions that cause a discrepancy between potential and actual levels of academic performance as predicted by the person’s intellectual abilities. Learning disorders involve impairments or difficulties in concentration or attention, language development, or visual and aural information processing. Diagnosis includes cognitive, educational, speech and language, medical, and psychologic evaluations. Treatment consists primarily of educational management and sometimes medical, behavioral, and psychologic therapy.
Learning disorders are considered a type of neurodevelopmental disorders. Neurodevelopmental disorders are neurologically based conditions that appear early in childhood, typically before school entry. These disorders impair development of personal, social, academic, and/or occupational functioning and typically involve difficulties with the acquisition, retention, or application of specific skills or sets of information. The disorders may involve dysfunction in attention, memory, perception, language, problem-solving, or social interaction. Other common neurodevelopmental disorders include attention-deficit/hyperactivity disorder, autism spectrum disorders, and intellectual disability.
Specific learning disorders affect the ability to
Thus, these disorders involve problems in reading, mathematics, spelling, written expression or handwriting, and understanding or using verbal and nonverbal language (see Table: Common Specific Learning Disorders). Most learning disorders are complex or mixed, with deficits in more than one system.
Although the number of children with learning disorders is unknown, about 5% of the school-age population in the US receives special educational services for learning disorders. Among affected children, boys outnumber girls 5:1.
Learning disorders may be congenital or acquired. No single cause has been defined, but neurologic deficits are evident or presumed. Genetic influences are often implicated. Other possible causes include
Potential postnatal factors include exposure to environmental toxins (eg, lead), CNS infections, cancers and their treatments, trauma, undernutrition, and severe social isolation or deprivation.
Common Specific Learning Disorders
Children with learning disorders typically have at least average intelligence, although such disorders can occur in children with lower cognitive function as well. Symptoms and signs of severe disorders may manifest at an early age, but most mild to moderate learning disorders are not recognized until school age, when the rigors of academic learning are encountered.
Affected children may have trouble learning the alphabet and may be delayed in paired associative learning (eg, color naming, labeling, counting, letter naming). Speech perception may be limited, language may be learned at a slower rate, and vocabulary may be decreased. Affected children may not understand what is read, have very messy handwriting or hold a pencil awkwardly, have trouble organizing or beginning tasks or retelling a story in sequential order, or confuse math symbols and misread numbers.
Disturbances or delays in expressive language or listening comprehension are predictors of academic problems beyond the preschool years. Memory may be defective, including short-term and long-term memory, memory use (eg, rehearsal), and verbal recall or retrieval. Problems may occur in conceptualizing, abstracting, generalizing, reasoning, and organizing and planning information for problem solving.
Visual perception and auditory processing problems may occur; they include difficulties in spatial cognition and orientation (eg, object localization, spatial memory, awareness of position and place), visual attention and memory, and sound discrimination and analysis.
Some children with learning disabilities have difficulty following social conventions (eg, taking turns, standing too close to the listener, not understanding jokes); these difficulties are often components of mild autism spectrum disorders as well.
Short attention span, motor restlessness, fine motor problems (eg, poor printing and copying), and variability in performance and behavior over time are other early signs.
Difficulties with impulse control, non–goal-directed behavior and overactivity, discipline problems, aggressiveness, withdrawal and avoidance behavior, excessive shyness, and excessive fear may occur. Learning disabilities and attention-deficit/hyperactivity disorder (ADHD) often occur together.
Children with learning disorders are typically identified when a discrepancy is recognized between academic potential and academic performance. Speech and language, cognitive, educational, medical, and psychologic evaluations are necessary for determining deficiencies in skills and cognitive processes. Social and emotional-behavioral evaluations are also necessary for planning treatment and monitoring progress.
Cognitive evaluation typically includes verbal and nonverbal intelligence testing and is usually done by school personnel. Psychoeducational testing may be helpful in describing the child’s preferred manner of processing information (eg, holistically or analytically, visually or aurally). Neuropsychologic assessment is particularly useful in children with known CNS injury or illness to map the areas of the brain that correspond to specific functional strengths and weaknesses. Speech and language evaluations establish integrity of comprehension and language use, phonologic processing, and verbal memory.
Educational assessment and performance evaluation by teachers’ observations of classroom behavior and determination of academic performance are essential. Reading evaluations measure abilities in word decoding and recognition, comprehension, and fluency. Writing samples should be obtained to evaluate spelling, syntax, and fluency of ideas. Mathematical ability should be assessed in terms of computation skills, knowledge of operations, understanding of concepts, and interpretation of "word problems."
Medical evaluation includes a detailed family history, the child’s medical history, a physical examination, and a neurologic or neurodevelopmental examination to look for underlying disorders. Although infrequent, physical abnormalities and neurologic signs may indicate medically treatable causes of learning disabilities. Gross motor coordination problems may indicate neurologic deficits or neurodevelopmental delays. Developmental level is evaluated according to standardized criteria.
Psychologic evaluation helps identify ADHD, conduct disorder, anxiety disorders, depression, and poor self-esteem, which frequently accompany and must be differentiated from learning disabilities. Attitude toward school, motivation, peer relationships, and self-confidence are assessed.
Diagnosis is made clinically based on criteria in the Diagnostic and Statistical Manual of Mental Disorders,Fifth Edition (DSM-5), and requires evidence that at least one of the following has been present for ≥ 6 mo despite targeted intervention:
Inaccurate, slow and/or effortful word reading
Difficulty understanding the meaning of written material
Difficulty writing (eg, multiple grammar and punctuation errors; ideas not expressed clearly)
Difficulty mastering number sense (eg, understanding the relative magnitude and relationship of numbers; in older children, difficulty doing simple calculations)
Difficulty with mathematical reasoning (eg, using mathematical concepts to solve problems)
Skills must be substantially below the level expected for the child's age and also significantly impair performance at school or in daily activities.
Treatment centers on educational management but may also involve medical, behavioral, and psychologic therapy. Effective teaching programs may take a remedial, compensatory, or strategic (ie, teaching the child how to learn) approach. A mismatch of instructional method and a child’s learning disorder and learning preference aggravates the disability.
Some children require specialized instruction in only one area while they continue to attend regular classes. Other children need separate and intense educational programs. Optimally and as required by US law, affected children should participate as much as possible in inclusive classes with peers who do not have learning disabilities.
Drugs minimally affect academic achievement, intelligence, and general learning ability, although certain drugs (eg, psychostimulants, such as methylphenidate and several amphetamine preparations) may enhance attention and concentration, allowing children to respond more efficiently to instruction.
Many popular remedies and therapies (eg, eliminating food additives, using antioxidants or megadoses of vitamins, patterning by sensory stimulation and passive movement, sensory integrative therapy through postural exercises, auditory nerve training, optometric training to remedy visual-perceptual and sensorimotor coordination processes) are unproved.