Learning Disabilities

(11-5-13)

A most controversial subject

Questions to consider:

• What is a learning disability?
• How shall we identify a learning disability?
• How do we best remediate/educate a learning disability?
• What are the causes of learning disabilities?
• Are there different types of learning disabilities?

The current picture

The concept of a learning disability

A difficulty in learning that cannot be accounted for by any of the well understood limitations on academic achievement: general intelligence, sensory or motor disability, emotional or behavior disorder, environmental or educational deficiency

Definitions of LD

There is no universally accepted definition of learning disability

Questions and disagreements surround the issue of exclusionary criteria, relationship to intelligence, hypothesized basic psychological deficits, gender distribution, etiology, determination of a “significant discrepancy”, and the nature of the frequent associations with comorbid problems

Common elements in definitions of learning disorders

• Academic problems with intraindividual variation in underachievement
• Ability/Achievement discrepancy
• Heterogeneous population
• Possible CNS dysfunction
• Persistent problems affecting adjustment at all ages
• Association with language problems, especially in early history
• Association with perceptual problems, especially in early history
• Significant potential for multiple handicaps (comorbidity with other disorders is high)

Individuals with Disabilities Act (IDEA)

Reauthorized Definition of Learning Disabilities (1997)

In 1997 a reauthorization of IDEA (Public Law 105-15) was signed into law by the federal government. The definition of learning disability included was essentially the same as the previous USOE definition (1977) used in P.L. 94-142 and read:

• A. In General–The term “specific learning disability” means a disorder in one or more of the basic psychological processes involved in understanding or in using language, spoken or written, which disorder may manifest itself in imperfect ability to listen, think, read, write, spell, or do mathematical calculations.
• B. Disorders Included–Such term includes such conditions as perceptual disabilities, brain injury, minimal brain dysfunction, dyslexia, and developmental aphasia.
• C. Disorders Not Included–Such term does not include a learning problem that is primarily the result of visual, hearing, or motor disabilities, of mental retardation, of emotional disturbance, or of environmental, cultural, or economic disadvantage. (Individuals with Disabilities Education Act Amendments of 1997, Sec. 602(26), p. 13)

DSM-IV definition of Learning Disorder

• “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.” (DSM-IV-TR, 2000, p. 49)
• “Substantially below is defined as a discrepancy of more than 2 standard deviations between achievement and IQ.” (DSM-IV-TR, 2000, p. 49)
• “If a sensory deficit is present, the learning difficulties must be in excess of those usually associated with the deficit.” (DSM-IV-TR, 2000, pp. 49-50)

DSM 5 definition of a Specific Learning Disorder

• “Specific learning disorder is a neurodevelopmental disorder with a biological origin that is the basis for abnormalities at a cognitive level that are associated with the behavioral signs of the disorder.” (DSM 5, 2013, p. 68)
• “One essential feature for specific learning disorder is persistent difficulty learning keystone academic skills (Criterion A), with onset during the years of formal schooling (i.e., the developmental period).” (ibid. p. 68)
• Key academic skills: reading single words accurately and fluently, reading comprehension, written expression and spelling, arithmetic calculation, mathematical reason (solving mathematical problems)
• DSM 5 estimates prevalence in children as between 5-15% of school aged youth; notes prevalence in adults is unknown but may be approximately 4%
• more common in males (rations of 2:1 to 3:1), “cannot be attributed to factors such as ascertainment bias, definitional or measurement variation, language, race, or socioeconomic status.” (ibid. p. 73)

Characteristics of children with LD

Method of identification significantly affects population identified:

• Placement/performance discrepancy
  • years below grade level is probably an inadequate standard but may not be extinct
  • minimal testing requirement would be an achievement measure (and some basis upon which to judge intelligence to be normal–this might be observation and clinical judgment)
• Ability discrepancy: predict achievement level based on tested IQ and compare with measured achievement
  • minimal testing requirement would include and individually administered IQ test and an achievement measure
• Statistical discrepancy after correction for correlation between measure (ability and achievement measures are typically positively correlated) and regression effects (regression toward the mean)
  • a regression equation compensates for statistical effects–this is the most conservative (stringent) approach to establishing an ability/achievement discrepancy
  • As increasing restrictive standards are used, 3 clear effects can be seen in the population identified as “learning disabled”:
    • 1. a small number of children are identified: population of “affected” children shrinks
    • 2. the average severity of the identified cases increases (you have progressively excluded the milder cases)
    • 3. the homogeneity of the identified population increases

The current struggle

Federal criteria for LD designation are changing. After decades of a definition based on the “discrepancy model” alternative formulations are being actively debated and are finding their way into law.

• The Discrepancy Model
  • ability-achievement differences
    • Problems with the discrepancy model
      • 1. it has not lead to effective instruction or remediation
      • 2. it ignores children who are struggling academically but do not show a discrepancy between tested intelligence and achievement
      • 3. it is difficult to use with children in the early grades
• The search for an alternative:
  • The Comprehensive Assessment/Clinical Judgment Model/Diagnostic Approach (intraindividual discrepancy)
    • 1. Eliminate discrepancy criteria
    • 2. Base identification of LD on a comprehensive individualized assessment of abilities; using multiple methods, measures, sources of information, and clinical judgment
    • 3. Decisions on eligibility made by an interdisciplinary team
  • The Response to Intervention/Response to Treatment Model
    • Curriculum Based Instruction methodology: a testing strategy that uses to student’s curriculum as the basis to plan learning needs and intervention. “test, teach, test”
      • 1. Eliminate discrepancy criteria
      • 2. Diagnose LD if the child fails to respond to efforts at academic remediation

Prevalence

• approximately 5% of school aged children is a common estimate
• 50% of the children in special education

Sex Ratio

• M > F identified in most reports
• Shaywitz & the Connecticut Longitudinal Study (1990): referral bias
• Rutter et al., (2004) findings: reading disability significantly higher in males

Course

• Varies most clearly with severity
• Mild cases may “disappear”
• Moderate to severe cases usually appear stable

Associated Problems/Outcome

• Risk for dropping out of school (near 40%) approximately 1.5 national average (APA, 2000)
• Comorbid behavior problems approximately 3 times high than norm by 8 years of age
• behavior problems in general population
  • age 4 …………………………………. age 8
  • 2% …………………………………….. 9%
• behavior problems in youth with learning disorders
  • age 4 ……………………………………age 8
  • 11% ……………………………………. 27%
• A review of publications by Kavale & Forness (1996) suggested that approximately 75% of students with learning disabilities have social skill deficits.
  • These children tend to be more isolated and less popular with peers (Vallance, Cummings, & Humphries, 1998).
  • Gadeyne, Ghespuiere, & Onghena (2004) found children with learning difficulties more likely to have deficits in attention, social behavior, and behavior problems; but noted found variations defending on subpatterns of learning problems: low achievement students were more likely experiencing poor academic self-concept versus students with specific learning disabilities, who were more likely to experience social problems.
• Areas of disability/functional limitations associated with learning disorders:
  • Academic achievement: reading, written expression, arithmetic skills
  • Attention and concentration: even without diagnosed ADD/ADHD, there may be problems with cognitive focus, distractibility, and vigilance relative to age peers
  • Memory: learning and recall, incidental learning, and general fund of knowledge may be poor relative to age peers
  • Executive functions: planning, judgment, abstract reasoning, problem solving, generalization and discrimination based on feedback may be poor relative to age peers
  • Social skills: deficits in communication, nonverbal social perception, awareness of social conventions, and specific social skills (appropriate eye contact, posture, voice loudness, assertiveness) may limit adjustment and achievement. The adaptive behavior of children with LD’s was found by Leigh (1987) to be poorer than typical children but better than children with mental retardation.
  • Poor self-esteem, limited self-confidence, performance anxiety, self-defeating behaviors, and limit goal directed behavior may further limit success. Children with LD’s have been found to have more anxiety (Stein & Hoover, 1989) and higher levels of depression (Hall & Haws, 1989) than typical learners.

Subclassification

• Intensely debated
• Reading Disorders
• Mathematics Disorders
  • May be as common as reading disorders but have received less attention
  • Some investigators have argued arithmetic learning disability is unique (Rourke, 1993), while others have argued that these problems are part of more generalized learning disability (Fleischner, 1994). Math and reading disabilities may share common underlying processing difficulties; they are frequently comorbid: co-occurrence estimates as high as 40% are reported (Hale & Fiorello, 2004).
• Disorders of Written Expression
  • reportedly rarely occur in isolation, usually comorbid with other learning and language disabilities
  • handwriting problems
  • spelling
    • “There are only 26 letters in the alphabet, but over 500 spellings used in representing the 44 phonemes in the English language (Tompkins, 1998).” (Hale & Fiorello, 2004, p. 227)
    • “benign spelling dyspraxia”
  • composition
• Nonverbal Learning Disorders (NVLD)
• Academic Underachievement

Comorbidity

• Other emotional, behavioral, and cognitive problems are often found in association with learning disorders
• Frequently report comorbid problem areas:
  • Attention-Deficit/Hyperactivity Disorder (ADHD)
  • Disruptive Behavior Disorders–Oppositional-Defiant Disorder (ODD) and Conduct Disorder
  • Mood Disorders and Anxiety Disorders (often latter: adolescence or adulthood)
  • Substance Abuse/Substance Dependence (this observed relationship may not be functional [e.g., “real”], but rather mediated by the association with ADHD and Disruptive Behavior Disorders (which do have functional links to substance use problem)

Treatment/Education

• No primary intervention to date has proved successful (This may be changing in the case of some reading disabilities).
• Most significant factor in remediation has been amount of instruction in skill deficit area (“time on task”).
  • Individualized instructional approaches are often helpful (single case study approaches, response to intervention models)
    • Learning characteristics reported in students identified with LD have included:
      • perceptual problems
      • language problems
      • attention and concentration problems
      • memory problems
      • cognitive/information processing problems
        • information processing–the way a person acquires, retains, and manipulates ideas
      • executive function problems
        • executive functions: planning a task, carrying this plan out, checking progress and using feedback, verifying that results meet goal
• Treatment of comorbid conditions can reduce interference with education