Learning Disabilities/Disorders – Official Definitions


Official Definitions of LD used in Canada




Official Definitions of LDS:

Psychologists may use different definitions and criteria to diagnose a Learning Disability/Learning Disorder.

The Learning Disabilities Association of Canada (LDAC) definition and criteria is widely used by psychologists in Canada.

The Diagnostic and Statistical Manual of Mental Disorders – Fifth Edition (DSM-5), which was developed by the American Psychiatric Association, is also utilized by psychologists. The DSM-5 uses the term “Specific Learning Disorders (SLD) instead of Learning Disabilities.

LDAC – Learning Disabilities Association of Canada

official definition of Learning Disabilities


Adopted by the Learning Disabilities Association of Canada January 30, 2002

and Re- endorsed on March 2, 2015

Learning Disabilities refer to a number of disorders which may affect the acquisition, organization, retention, understanding or use of verbal or nonverbal information.

This means an LD might affect how you learn, organize, remember or understand information.

These disorders affect learning in individuals who otherwise demonstrate at least average abilities essential for thinking and/or reasoning. As such, learning disabilities are distinct from global intellectual deficiency.

Learning disabilities result from impairments in one or more processes related to perceiving, thinking, remembering or learning.

These include, but are not limited to:

Language processing:
is the understanding and expression of oral and written language; includes vocabulary, word structure, sentence structure and meaning across sentences.

Phonological processing:
is the ability to identify the different sounds that make words and to associate and manipulate these sounds within words we speak and write.

Visual processing:
is the ability to make sense of information taken in through the eyes. Difficulties with visual processing affect how visual information is interpreted, or processed by the brain.

Processing speed:
refers to the pace at which you are able to perceive information (visual or auditory), make sense of that information, and then respond.

Memory and Attention:
Short-term memory is the process by which you hold on to information as long as you are concentrating on it.

Long-term memory refers to the process by which you store information that you have repeated often enough.

Attention:  is the ability to sustain attention to a task

Executive Functions
is needed for planning, organization, strategizing, attention to details and managing time and space.

Learning disabilities range in severity and may interfere with the acquisition and use of one or more of the following:

oral language (e.g. listening, speaking, understanding);
reading (e.g. decoding, phonetic knowledge, word recognition, comprehension);
written language (e.g. spelling and written expression);
and mathematics (e.g. computation, problem solving).
Learning disabilities may also involve difficulties with organizational skills, social perception, social interaction and perspective taking.

Learning disabilities are lifelong.

The way in which they are expressed may vary over an individual’s lifetime, depending on the interaction between the demands of the environment and the individual’s strengths and needs.

Learning disabilities are suggested by unexpected academic under- achievement or achievement which is maintained only by unusually high levels of effort and support.

Learning disabilities are due to genetic and/or neurobiological factors or injury that alters brain functioning in a manner which affects one or more processes related to learning.

These disorders are not due primarily to hearing and/or vision problems, socio-economic factors, cultural or linguistic differences, lack of motivation or ineffective teaching, although these factors may further complicate the challenges faced by individuals with learning disabilities.

Learning disabilities may coexist with various conditions including attentional, behavioural and emotional disorders, sensory impairments or other medical conditions.

For success, individuals with learning disabilities require early identification and timely specialized assessments, interventions and accommodations in the home, school, community and workplace settings.

The interventions need to be appropriate for each individual’s learning disability subtype and, at a minimum, include the provision of:

specific skill instruction
compensatory strategies
and self-advocacy skills

DSM-5 – Diagnostic and Statistical Manual for Mental Disorders-5th


DSM-5 uses the umbrella term, specific learning disorders and then areas of impairment and specific difficulties:

Specific Learning Disorder with impairment in reading:

Word reading accuracy

Reading rate/fluency

Reading comprehension

Specific Learning Disorder with impairment in writing:

Spelling accuracy

Grammar and punctuation accuracy

Clarity or organization of written expression

Specific Learning Disorder with impairment in math:

Number sense

Memorization of arithmetic facts

Accurate or fluent calculation

Accurate math reasoning

According to DSM-5, the diagnosis of a specific learning disorder includes the following symptoms:


Persistent difficulties in reading, writing, arithmetic, or mathematical reasoning skills during formal years of schooling.
Symptoms may include inaccurate or slow and effortful reading, poor written expression that lacks clarity, difficulties remembering number facts, or inaccurate mathematical reasoning.


Current academic skills must be well below the average range of scores in culturally and linguistically appropriate tests of reading, writing, or mathematics. Accordingly, a person who is dyslexic must read with great effort and not in the same manner as those who are typical readers.
Learning difficulties begin during the school-age years.
The individual’s difficulties must not be better explained by developmental, neurological, sensory (vision or hearing), or motor disorders and must significantly interfere with academic achievement, occupational performance, or activities of daily living (APA, 2013).



LDAC Official Definition:



DSM-5 Definition