Learning Disabilities: Implications for Policy Regarding Research and Practice: A Report by the National Joint Committee on Learning Disabilities

Points of General Agreement About Learning Disabilities

There is a general agreement that learning disabilities are neurobiologically based, involve cognitive processes, and affect learning. Learning disabilities persist in various forms across the life span, frequently with precursors—most often, language delays or language deficits in early childhood—appearing before formal schooling begins and continuing into adulthood (NJCLD, 2008). Furthermore, learning disabilities occur regardless of such factors as an individual’s culture, race, language, gender, or socioeconomic status.

SLD is one of the 13 disability categories in which students may qualify for special services under the Individuals With Disabilities Education Improvement Act (IDEA) of 2004. The definition of SLD used in federal education laws refers to disorders that adversely affect learning but are not primarily the result of other disorders such as intellectual disability or hearing impairment. Notably, eligibility for special education services is determined by a student’s educational performance and is, therefore, influenced by the quality of instruction and other aspects of the educational setting. Nationwide, nearly 40% of students who have been found eligible for special education programs are served under the SLD category (Horowitz, Rawe, & Whittaker, 2017). Individuals with learning disabilities are also protected under the Americans With Disabilities Act (ADA) of 1990, which identifies learning disability as a disability that affects activities of daily living.

Individuals with learning disabilities may experience significant difficulties in one or more areas of educational performance. IDEA (2004) identified eight areas of underachievement: listening comprehension, verbal expression, basic reading skill, reading fluency, reading comprehension, written expression, mathematical computation, and mathematical problem solving. Although various disciplines use different terminology to identify aspects of learning disabilities—such as dyslexia, reading disorder, dyscalculia, math disability, dysgraphia, and disorders of written expression—there is agreement that these disorders are considered types of learning disabilities.

Learning disability may coexist with other disorders. For example, individuals with learning disabilities may manifest social–emotional, behavioral, or attentional difficulties, which may be either concomitant or secondary to learning disabilities. Although individuals with learning disabilities may share some characteristics with individuals who have other disabilities, the defining characteristic of a learning disability is that the cognitive processes affecting learning underlie the educational difficulties that the individual with learning disabilities experiences.

Learning disabilities exist across cultures, races, and languages, but they may differ from one culture or language to another. These differences may complicate identification, assessment, and instruction for students with learning disabilities. English language learners may be mistakenly considered to have learning disabilities (false positives) or may be overlooked for learning disabilities services because of limitations in their understanding and use of English (false negatives). Educators often express concerns about the over- and underidentification of students who are English language learners. Understanding a student’s needs depends upon the school’s capacity to assess whether learning disabilities are evident in the student’s primary language.

Individuals who are identified as intellectually gifted also may have learning disabilities. Although twice-exceptional individuals may appear to be functioning adequately in the classroom, their performance may be far below that which they are capable, given their intellectual ability. These students may be able to compensate for their learning disabilities-related challenges until the volume or intensity of work or assessment and grading procedures pose barriers to demonstrating their learning or accomplishing required tasks, which may cause a delay in identification and subsequent services for students until late in their academic careers.

Most students with learning disabilities have an uneven pattern of strengths and weaknesses that affects learning. The problems experienced by these students vary in severity and pervasiveness; some students experience deficits in only one area of functioning, whereas others experience difficulties in multiple areas. Regardless, students with learning disabilities require differentiated instruction as well as supports that address their specific learning needs.

Diverse disciplines—including education, psychology, speech–language pathology, and medicine—have broadened understanding of the neurobiological and neuropsychological aspects of learning disabilities. Promoting collaborative research and interprofessional practice across disciplines provides an evidence base that can be expected to advance the informed application of strategies, interventions, and best practices to address the needs of this population.

Common Misperceptions About Learning Disabilities

Common misunderstandings can result in policies and practices that create barriers to appropriate services for individuals with learning disabilities. Some misconceptions are clearly mistaken and harmful (e.g., individuals with learning disabilities are lazy, students with learning disabilities simply need greater motivation to succeed). Other misconceptions are more subtle, but they are equally insidious (e.g., learning disabilities are mild disabilities, learning disabilities can be cured, learning disabilities are synonymous with reading problems, the term learning disabilities is a catch-all term for other disabilities).

One common misperception regarding learning disabilities is that they are mild impairments. An individual’s learning disability may appear to be mild (perhaps even nonexistent) in some circumstances and more severe in others. Because learning demands, environments, and supports vary greatly across contexts and across the life span, variation in the functional impact of learning disability occurs. Each individual possesses an array of unique strengths and limitations representing a continuum of risk and resilience that greatly affects the extent to which learning disability interferes with learning and success across the life span.

A second misperception is that high-quality instruction in the general education classroom or in supplementary intervention programs can prevent or eliminate learning disabilities. High-quality instruction can mitigate the negative effects of learning disabilities. This is especially true when intervention occurs early in an individual’s life (NJCLD, 2006). However, many individuals with learning disabilities will need specialized instruction, accommodations, and compensatory strategies throughout life.

A third misperception occurs when learning disabilities are thought of as synonymous with reading disabilities. Although the majority of students who have been identified as having learning disabilities in school do have reading problems, learning disabilities also encompasses deficits in areas such as listening, speaking, mathematics, written expression, social–emotional, and executive function. These areas have lagged behind reading in research, funding, our level of understanding, and public policy solutions to support students with learning disabilities.

A fourth misperception involves the term learning disabilities being used as a generic term for individuals with other disabilities. Often, the term learning disabilities is mistakenly used to refer to students with intellectual and developmental disabilities, hearing impairments, autism, and other disabilities. These references treat learning disabilities as a catch-all term, thus diluting the construct of learning disabilities and threatening its integrity.

Unresolved Issues in Scholarship and Practice

There is general agreement within the scientific community that learning disabilities are a manifestation of atypical cognitive and linguistic processes that interfere with learning, but there is a lack of consensus about assessment, identification, and prevalence because of the complex nature of these processes. Learning disability is a widely accepted construct, and can be readily identified in its more severe forms. However, the underlying mechanisms of learning disabilities are complex and are the subject of steadily advancing cognitive and biological science. The following are some reasons why unresolved issues exist:

The cognitive processes underlying learning disabilities are often difficult to pinpoint. The processes underlying acquisition of early spoken language and literacy skills are established, but the processes underlying other areas—such as written expression, mathematics, and social cognition—are not as well understood.

The learning problems associated with learning disabilities are distributed along a continuum, so no definitive cut-point can be used to differentiate between individuals with and without learning disabilities.

Environmental factors or stressors (e.g., lack of educational opportunity or appropriate instruction, linguistic diversity, poverty, or emotional interference) can have effects on learning that are often difficult to distinguish from manifestations of learning disabilities.

The assessment of cognitive processes has been used in clinical evaluation and to determine eligibility for special education services, but there is ongoing debate regarding its value in learning disabilities identification or in informing educators about the efficacy of specific instructional methods.

Historically, learning disabilities have been identified in an exclusionary manner, referring to the absence of other explanatory factors such as intellectual disability. “Unexpected underachievement” has often been cited as the defining characteristic of learning disabilities. As research progresses and assessment measures improve, our understanding of learning disabilities as underachievement that cannot be explained by other causes is shifting toward the use of comprehensive identification procedures that help predict the probability of underachievement and inform instruction. We are coming to recognize that deficiencies in certain cognitive processes are indicators of learning disabilities that predict and, therefore, result in expected underachievement.

The relative merits of different methods of learning disabilities identification have been the subject of considerable debate. One long-standing method is to interpret psychoeducational assessment data, focusing on a student’s pattern of strengths and weaknesses. In 1977, federal special education regulations introduced the use of an ability-achievement discrepancy method of learning disabilities identification. Due to criticisms of the theoretical, psychometric, and empirical shortcomings of the discrepancy approach, the 2004 reauthorization of IDEA allowed for the use of a response to intervention (RTI) approach (NJCLD, 2005) as well as other scientifically based approaches to learning disabilities identification. RTI relies on early screening and analyses of academic performance over time to determine whether a child has both continued underachievement and an insufficient rate of improvement when provided with appropriate instruction and targeted interventions. No single method has proven superior as a means of making diagnostic decisions or sufficient as a sole source of evaluation data. The 2010 NJCLD report, Comprehensive Assessment and Evaluation of Students With Learning Disabilities, provides guidance in this area.

Another unresolved issue is the prevalence of learning disabilities. Reports to Congress on IDEA show that about 5% of school-age children and youth are receiving services under the SLD category. Prevalence rates vary from state to state and even from school to school. Learning disabilities prevalence estimates vary as a result of how each state sets eligibility criteria and depending on the source of data (epidemiological, survey, child count, or research). Some of the variation in estimates may either overrepresent or underrepresent the actual prevalence of learning disabilities.

Recommendations

The NJCLD recommends that federal and state governments pursue the following policies and activities: