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How does one differentiate between mild, moderate, and severe LDs? How can I tailor my interventions/strategies to the needs of students with differing degrees of learning disabilities?

Answered by Dr. Maria Kokai M.A., PhD., C.Psyc., Chief Psychologist with the Toronto Catholic District School Board.

According to the definition, learning disabilities are due to genetic, congenital and/or acquired neurobiological factors that result in impairments in one or more psychological processes related to learning. In view of the biological/neuropsychological nature of the disability, the formulation and communication of a diagnosis of learning disabilities is a complex process that requires professional training and skill. Professionals from a variety of disciplines (e.g., psychology, education, speech-language pathology, occupational therapy, medicine, audiology, etc.) play a significant role in identifying “at risk” individuals and in contributing to the evaluation, as well as to the development and implementation of a range of interventions. In Ontario, however, the communication of a diagnosis is controlled under the Regulated Health Professions Act, and may be performed only by appropriately qualified members of the College of Psychologists and the College of Physicians and Surgeons.

Diagnostic Criteria for Learning Disabilities All of the following criteria must be met for a diagnosis of a learning disability to be made.

  1. A non-random, clinically significant discrepancy between one or more of the specific psychological processes related to learning (phonological processing; memory and attention; processing speed; language processing; perceptual-motor processing; visual-spatial processing; executive functions) and otherwise average abilities essential for thinking and reasoning.
  2. Academic achievement that is unexpectedly low relative to the individual’s thinking and reasoning abilities OR academic achievement that is within expected levels, but is sustainable only by extremely high levels of effort and support.
  3. Evidence that learning difficulties are logically related to observed deficits in specific psychological processe.
  4. Evidence that learning difficulties cannot primarily be accounted for by:

- other conditions, such as global developmental delay, primary sensory deficits (e.g., visual or hearing impairments), or other physical difficulties;

- environmental factors, such as deprivation, abuse, inadequate or inappropriate instruction, socio-economic status, or lack of motivation

- cultural or linguistic diversity.

- any other co-existing condition such as Developmental Coordination Disorder, Attention Deficit Hyperactivity Disorder or anxiety.

- taken from the Learning Disabilities Association of Ontario publication, “Recommended Practices For Assessment, Diagnosis and Documentation of Learning Disabilities” (2003)

Although there are no formalized criteria to define what constitutes a mild, moderate or severe LD, generally we can determine the severity of the LD by the following:

  • The number of skill areas affected by the LD (such as different areas of academic skills, life skills, social skills, etc.); and
  • The severity of the deficits in psychological processes and the degree of impairment in the skill areas affected by the LD and the degree to which the impairment interferes with the person’s everyday functioning, despite of appropriate intervention/remediation (in the different academic skills, life skills, social skills, etc.)

Typically, the more skill areas are affected and the higher the degree of impairment, the more severe the LD is.

For example, a student with some deficits in phonological processing may have difficulties in learning to decode words, but once basic reading skills have been acquired, is able to read. However he/she will continue to require a longer time to read and understand paragraphs. This would be consistent with a mild LD.

On the other hand, if a student has deficits in a number of psychological processes, for example working memory, processing speed, phonological processing and language processing, many academic skills connected with these can be significantly impaired: oral communication and listening comprehension, reading decoding as well as reading comprehension, spelling and writing, understanding the language of math, remembering instructions, completing mental computations, etc. The significant impairments in these areas will inevitably impact most of the other academic areas (including math), as well as daily communication and social functioning, making the LD severe.

The programming and support required needs to be tailored to the individual needs of the person with LDs, as the impact of LDs vary widely.

For example, taking the above example for a mild LD, with a specific and focused reading remediation, the reading skills can be improved, while all the other academic, and social skills are age appropriate. The student will be able to function at grade level with some accommodations (e.g. longer time provide for reading, relying on other ways to access information, etc.), and no other academic or other skill areas will be affected.

In the case of the second example, both intensive remediation/intervention to improve these skills (reading, decoding, vocabulary building, social communication skill instruction, etc.), as well as Assistive Technology and appropriate accommodations to access the curriculum in all subject areas will be required.

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Learning Disabilities Association of Ontario Recommended Practices For Assessment, Diagnosis and Documentation of Learning Disabilities (2003) http://www.ldao.ca/documents/Assessment%20Protocols_Sept%2003.pdf

Related Resources on the LD@school Website

Click here to access the Ask the Experts answer to the question, “How are LDs in mathematics typically diagnosed?” by Dr. Todd Cunningham.

Click here to access the practice-informed summary, “Universal Design for Learning (UDL)”.

Click here to access the practice-informed summary, “Differentiated Instruction”.

Click here to access the slide presentation, “Demystifying the Psycho-Educational Assessment Report”.

Click here to access the article and video, “York Waterfall Chart: Understanding Learning Disabilities – How Processing Affects Learning”.

Click here to view the video, “The Tiered Approach”, filmed in partnership with the Thunder Bay Catholic District School Board (TBCDSB).

Picture of Dr. Maria KokaiDr. Maria Kokai holds a PhD in clinical psychology and is currently the Chief Psychologist for The Toronto Catholic District School Board. Prior to her current position, Dr. Kokai worked as a school psychologist for 20 years. As a school psychologist, and in her current role as Chief Psychologist, she has been involved in professional development for educators, and in the selection, implementation and evaluation of various board wide intervention programs in the areas of LD, resilience and mental health.  She is a member of the Ontario Psychological Association, as well as the OPA Section on Psychology in Education and OPA-Ministry of Education Liaison Committee. Dr. Kokai also serves as an advisory member of the LDAO’s LD@school project.