According to the National Advisory Board on Handicapped Children, a learning disability is a dysfunction
in one or more of the physiological processes involved in using or listening to written or spoken word.
These disorders can be in reading, writing, speaking, listening, or arithmetic skills. The National Joint
Committee on Learning Disabilities states that a learning disability is a generic term referring to a
heterogeneous group of disorders manifested by significant difficulties in the acquisition and use of
listening, speaking, reading, writing, reasoning, and mathematical skills. It is presumed that these issues
are due to a dysfunction with the central nervous system, and that they are intrinsic to the individual.
Public Law 94-142
The law stipulated that for a child to be considered learning-disabled they have to meet certain criteria.
The first of these criteria was that the child did not achieve in school to the ability he or she should
depending on their age and ability when provided with normal learning experiences. The second criteria
was that there was a severe discrepancy between aptitude and achievement in one or more of these
areas: oral communication, listening comprehension, written expression, basic reading skills, reading
comprehension, mathematical calculation, or mathematical reasoning.
AE and GE Scores
Age-equivalent and grade-equivalent scores indicate the level of growth or development a child has
reached, using prior knowledge of what is typical at certain ages or grades. Tests are given to large
representative samples whose scores provide standards or norms for aptitude or achievement to which
everyone else is compared. Age- and grade-equivalent scores are ordinal scores; that is, they tell us how
an individual does in comparison to others, but not how much better or worse someone is. Thus, it is
not possible to determine how severe a discrepancy may be.
Percentile ranks indicate the percentage of the normative or standardization group that is below an
individual’s percentile rank score. An individual’s score is the percent of average individuals the person
is better than in that test area. Percentile ranks are ordinal scores; that is, they tell us how an individual
does in comparison to others, but not how much better or worse. Thus, it is not possible to determine
how severe a discrepancy may be with percentile ranks.
Standard scores indicate the number of standard units above or below the mean that an individual’s
score is. These use the standard deviation of the score distribution around the mean to show how far
an individual’s score differs from the mean. Scores can be reported in terms of the number of standard
deviation from the mean, or in Z-scores. To eliminate negative numbers, most tests use scores with
means of 100 and standard deviations of 15. Standard scores give us the advantage of telling us how
much better or worse one score is than another.
Severe Discrepancy between Aptitude and Achievement
Most jurisdictions prefer to use standard scores in computing aptitude-achievement discrepancies and
use a difference of two standard deviations between aptitude and achievement as indicating the
presence of a severe discrepancy. If a child received a standard score of 110 on an aptitude test, he or
she would have to earn a standard score of 80 or less on an achievement test for the difference to
qualify as a severe discrepancy.
Reliability of Difference Scores
For each test score, there is a reliability associated with it. By subtracting one score from the other the
reliability of difference scores can be computed. This score is considerably less than the reliability of
individual scores. The higher the correlation between aptitude and achievement, the lower the reliability of difference between them. For aptitude-achievement difference scores to be meaningful,
aptitude scores must predict achievement scores, and test constructors must strive for almost error-free
measurement. Both scores must have high test-retest reliability but a low correlation between them,
and the reliability of difference between aptitude and achievement is less than the reliability of the
individual test scores. The reliability of difference of 0.60 is considerably lower than what is considered
IDEA 2004, 2006
The Individuals with Disabilities Education Improvement Act (IDEA) states that while a severe
discrepancy between aptitude and achievement could be included as evidence for a learning disability,
identification of a learning disability must not require a demonstration of severe discrepancy between
aptitude and achievement.
Response to Intervention (RTI)
Response to intervention is a prevention model to limit or prevent academic failure by providing
“evidence-based teaching procedures” for all students in general education. Tier 1 is high-quality
instruction in general education and monitoring of student progress, which includes 80% of students.
Tier 2 is more intensive evidence-based instruction while progress monitoring continues, which includes
10-15% of students. Tier 3 is highly intensive, evidence-based interventions taught in small groups or
individually while continuing progress monitoring, which includes 5-10% of students. Benefits of
response to intervention technique are that it focuses on earlier identification and prevention of
disabilities and it promotes shared responsibility and collaboration.
LDAO Definition of Learning Disabilities
Learning disabilities are a variety of disorders that affect the acquisition, retention, understanding,
organization, or use of verbal and/or non-verbal information. These disorders result from impairments
in one or more psychological processes related to learning, in combination with otherwise average
abilities essential for thinking and reasoning. Learning disabilities are specific impairments and are thus
distinct from intellectual disabilities, which are global. Learning disabilities range in severity and
invariably interfere with the acquisition and use of one or more important skills, such as oral language,
reading, writing, and mathematics. The Learning Disabilities Association of Ontario (LDAO) focuses on
impairments in psychological processes related to learning in combination with otherwise average
thinking or reasoning skills, unexpected low academic achievement, and average achievement attained
by a child at the expense of unrealistically high levels of effort or intensive educational support.
Test assumptions include assumptions that: the tester is adequately trained, the sample of behaviour
elicited in the test situation is adequate in amount and representative of the domain being sample, the
client has been exposed to comparable culture, error will be present in any measurement obtained, and
only present behaviour is observed and future behaviour can only be inferred.
Test-Retest Consistency Reliability
Test-retest consistency refers to stability in scores over time, and is determined by giving the test to a
large group of individuals, then giving them the test again at a later time. If an individual receives similar
scores on the test on 2 separate occasions, the test is consistent. Results are expressed as a reliability
coefficient, from -1 to 1, and tests with a coefficient of 0.80 or higher are acceptable.
Internal Consistency Reliability
Internal consistency is the extent to which items on a test assess the same thing. If items on a test
measure different things, the test has low internal consistency. By correlating each item on the test with responses to other items in the test, we get a correlation, and a correlation of 0.90 or higher is
Validity is the extent to which a test measures what it is supposed to measure. It is difficult to
determine the validity of an intelligence test. The validity of intelligence tests is often determined by
how well they predict performance on achievement tests. This is determined by computing a
correlation coefficient between aptitude and achievement tests. Correlations between 0.4 and 0.6 are
considered to by significant.
Norms are the standards of comparison. A test is given to a large group of people, called the
standardization group, and scores made by people in this group are called test norms. Other people
who take the test are then compared to these test norms. It is difficult to compare the scores children
get on two tests that are normed on different samples of children, and very few published standardized
tests are normed on the same population.
Executive functions are the ability to control and direct one’s own learning. Planning, organizing,
monitoring activities, inhibiting responses, and attending to tasks at hand are all examples of executive
functions. Executive control directs flow of thinking, manages the cognitive processes during learning,
and keeps track of what information is being processed.
Time sampling techniques or running behaviour commentaries can provide data that speak to executive
Engaging a child to think aloud as he or she engages in tasks can provide rich sources of data that can
speak to the integrity of executive functions.
A standardized sample is a sample of peers of the same age group, with similar ethnicity, and balanced
in terms of parental education and geographical region, to which other children are compared. The
scores of the standardized sample provide norms to which other children are compared.
WISC-IV Composite Scores/Individual Subtests
Composite scores and the full-scale IQ are standardized scores with a mean of 100 and standard
deviation of 15. While the average scale for each subtest is 10, it is more reasonable to think of subtest
scores falling in an average range of scale scores between 7-13. Verbal comprehension includes
similarities, vocabulary, comprehension, and information. Perceptual reasoning includes block design,
picture concepts, matrix reasoning, and picture completion. Working memory includes digit span,
letter-number sequencing, and arithmetic. Processing speed includes coding, symbol search, and
Perceptual Organizational Skills (WISC-III)
The perceptual organizational skills measures visual-spatial organization and visual-motor skills within a
time limit, including mazes, picture arrangement, and object assembly. All three tasks focus on global
visual characteristics and require general interpretive perceptual skills. Block design and matrix
reasoning involve interpreting abstract designs that have to be constructed or completed using pieces
that are meaningless by themselves. Scaled Scores
A scaled score between 1-19 is assigned based on how the child compares to his or her same-aged
peers. A scaled score of 10 would indicate that the child performed at the level of the mean of the
distribution. The mean scaled score for each subtest is set at 10, and the standard deviation is set at 3.
Composite scores and the full scale IQ are standardized scores with means of 100 and standard
deviations of 15. If on average a child receives scores of 7 on the subtests within each composite score,
he or she would be assigned scores on each composite of 85 and an overall full scale IQ of 85.
A child achieving an IQ of 130 or higher is considered very superior, and this includes 2.2% of children.
120-129 is superior, including 6.7%. 110-119 is high-average, which is 16.1%. 90-109 is average, which
is 50% of children. 80-89 is low-average, which includes 16.1%. 70-79 is borderline, which includes 6.7%
of children. 69 and below is considered intellectually deficient, and includes 2.2% of children. An IQ of
115 and above includes 16% of children, and 85-115 is 68% of children. 16% of children have an IQ of 85
Object assembly requires an individual to put together puzzle pieces, which only make sense and
represent a common object when they are all put together properly.
Picture arrangement involves familiar objects or situations and requires the child to interpret pictures.
The mazes task is a performance test used in WISC-III and WISC-IV. It involves trial and error learning in
humans, which can be studies by giving students a task that is analogous to having white rats run
through a maze. The task given to the children is that they must navigate through a maze.
Visual Search Tasks
Visual search is a type of perceptual task requiring attention that typically involves an active scan of
visual environment for a particular object or feature among other objects or features. Visual search
tasks can take place with or without eye movements.
Global versus Local Features
Global features are the ‘gist’ of the scene, or the big picture. A local feature is an image pattern that
differs from its immediate neighbourhood. It is usually associated with a change of image property,
although it is not necessarily localized exactly on this change. The image properties commonly
considered are intensity, colour, and texture. Using both global and local features significantly improves
The Bender-Gestalt Test is a psychological test used to evaluate visual-motor maturity to screen for
developmental disorders or to assess neurological function or brain damage. The original test consists
of 9 figures, each on its own 3x5 card. The subject is shown each figure and asked to copy it on a piece
of blank paper. The test typically takes 7-10 minutes, after which the results are scored based on
accuracy and other characteristics.
Figure Copying In copying a figure, one must notice critical features in the display and incorporate that information in a
mental representation of the figure to by copies. It is one’s mental representation of the figure that
guides the hand that holds the pen.
Cognitive-behaviour modification (CBM) is used to teach children how to better orchestrate sub-skills.
CBM uses self-instructional skills to teach a child’s executive system how to better allocate resources.
Model for Visual Object Recognition
The model for visual object recognition involves: edge extraction, grouping of local image features,
segmentation of objects from the background, formation of structural descriptions of objects, and
accessing stored structural descriptions and semantic information.
Object Decision Tests
Patients with visual perceptual problems are often tested with object decision tests, where they are
asked to judge whether a picture is real or imaginary. If a patient does not know what an object is but
still knows that it does exist, they have some knowledge in the form of stored structural descriptions.
Gross Motor Skills
Gross-motor activities are grouped as walking activities, throwing and catching activities, and other
Various control processes are used to regulate the flow of information from one system to another.
They occur rapidly and automatically but are also influenced by instructions an individual is given, as
well as past experiences. Control processes include rehearsal, searching memory, encoding information,
classifying information, and setting criteria for making decisions
Incoming information, a stimulus input, enters the sensory register, and information in the sensory
register decays rapidly and must be copied with delay into short-term memory. Otherwise, it will just
Information is transferred or copied from one system to another. Although decay time is longer for
short-term memory, the information in short-term memory also decays rapidly. However, information
can be maintained in short-term memory through rehearsal, which regenerates the short-term memory
trace, or rehearsal buffer. 7 plus or minus 2 items can be stored in short-term memory.
Long-term memory provides an almost unlimited space for information.
Information can be maintained in short-term memory through rehearsal, which regenerates the short-
term memory trace, or rehearsal buffer. The rehearsal buffer has limited capacity when it is full, and the
entry of new items will bump out those in the buffer unless they are transferred into long-term memory.
Working memory includes parts of short-term memory, long-term memory, the rehearsal buffer, and
has access to control processes or procedures that are available in long-tem memory. Working memory
refers to the ability to hold and manipulate information in the mind for brief or more extended periods of time. It plays a vital role in the development of skills such as reading, writing, arithmetic, sports,
Assessment of Working Memory
This assessment goes beyond regular intelligence tests. Digit span, letter-number sequence, and
arithmetic all assess verbal working memory skills. The Susan Gathercole and Tracy Alloway assessment
better provides a broader assessment of working memory and short-term memory skills. It is entirely
administered by a computer, and includes, verbal and visuo-spatial short-term memory and working
Cogmed is designed to improve weak working memory skills. A project at the Institute of Child Study in
Toronto is an international research project working to assess the effectiveness of Cogmed.
Accretion, Restructuring, Schema Tuning
New schemes or schemas can be acquired in one of three ways. The first is restructuring, which refers
to forming new schemas in long-term memory, and completely reorganizing or reconceptualizing
knowledge about a topic or developing new skills. The second is accretion, which refers to adding new
knowledge to an existing structure or schema in long-term memory. The third is schema tuning, which
refers to making existing schemas more efficient, allowing highly tuned procedures to become
In some tests, after each trial the child is expected to forget the items just remembered, but for some
children the items seem to linger in working memory and continue being processed. As a result,
performance on subsequent trials suffers from proactive interference. Evidence for proactive
interference occurs when items from a previous trial intrude in subsequent trials. Children who are
particularly vulnerably to proactive interference may continue working on problems long after their
classmates have moved on and thus, fall behind.
Retrograde and Anterograde Amnesia
Retrograde amnesia is the loss of memory leading up to an operation or event; thus, loss of past
memories. Anterograde amnesia is the loss of memory of events occurring after an operation or event;
thus, loss of ability to create future memories.
Famous Persons Test
On the famous persons test, subjects are required to provide the names of famous people in pictures.
They are given pictures of people who were famous during years both before and after memory loss
DSM-IV-TR Diagnostic Criteria
Inattention includes short attention span, difficulty completing activities, forgetfulness, and easy
distractibility. Signs of hyperactivity are excessive talking, fidgeting, leaving a seat, and running around.
Barkley’s Attention Profile and Home and School Situation Questionnaire
A diagnosis of ADHD would require a detailed developmental history and data from parents and
teachers, documenting the prevalence and severity of inattentive and/or hyperactive behaviour. Russell
Barkley has development a questionnaire and rating scale for making a diagnosis. He recommends that
Systematic Behavioural Observations be made while a child works at usual classroom tasks or in other
situations and locales, and that the child’s parents complete a detailed developmental history questionnaire, and parents and teachers rate the frequency and severity of many behaviours and
academic strengths and weaknesses.
Conners’ CPRS and CTRS
The Conners’ Parent and Conners’ Teach Rating Scales are popular devices for obtaining information.
The Conners’ Scale has separate norms for boys and girls, and can be used for children and adolescents
from 3-15 years of age. It argues that only those that deviate significantly from the norm (the most
extreme 2.5%) should be diagnosed as having ADHD.
ACID Pattern on WISC-IV
Initially, it was proposed that children with ADHD leads to ACID pattern profiles on the WISC; that is, low
scores on arithmetic, coding, information, and digit span. While some ADHD children show this pattern,
many who achieve low scores on arithmetic, coding, information, and digit span would not be classified
with ADHD. There does not appear to be a WISC profile typical of ADHD.
TEACh is the Test of Everyday Attention for Children, which refers to the fact that tests in the TEA-Ch are
like games that children may play at home. These games are designed to assess many cognitive
functions involved in attention, such as selective attention, attentional control or switching, and the
ability to sustain attention. The ability to control and switch attention is executive functions.
BRIEF is the Behaviour Rating Inventory of Executive Function. It includes a brief questionnaire for
parents and teachers that is used to assess executive functional behaviour both at home and at school.
It has 86 items within 8 scales that measure different aspects of executive function.
Information Processing View of ADHD
There may be a flaw in some feature of information processing systems that affects how such
mechanisms operate. It is hypothesized that the executor can operate effectively only when it has at its
disposal an optimal amount of energy. If the energy falls below the critical level, then mechanisms are
commandeered to increase the energy in the system and the individual becomes engaged in stimulus
seeking. When this happens, there are not enough resources left to focus on any particular task, and if
this condition becomes chronic, the result is a disorder of attention and the person may become
Attentional Resource Allocation
When resources are properly allocated to the task at hand, the individual is said to be paying attention.
If all the resources are allocated to one task, the individual may become autistic or catatonic (too
focused). If resources are allocated too thinly, the individual may be distractible and impulsive. While it
is normal to be catatonic or impulsive at times, the problem arises when the balance habitually shifts in
one direction or the other. In some individuals there is a flaw in the mechanisms involved in resource
If energy falls below the critical level, then mechanisms are commandeered to increase the energy in the
system and the individual becomes engaged in stimulus seeking.
Reticular Activating System (RAS)
Arousal is controlled by a system involving the Reticular Activating System (RAS). The RAS lies deep in
the central core of the brain beneath the cerebral cortex and runs up from the brain stem into the mid-
brain. Nerve fibers from all the sensors in the body carry activity into the RAS, as well as other parts of
the CNS. The RAS spreads electrical activity diffusely over the rest of the CNS, arousing the brain. The amount of activity varies depending on where we are, and what is happening around us. There is an
optimal level of activity within the RAS for effective performance of any task. There are also centers
within the cerebral cortex and elsewhere in the CNS, which feed back into the RAS to monitor or
modulate RAS activity.
Double Blind Trial:
A double blind trial is when neither the participants nor the researchers know which participants belong
to the control group, as opposed to the test group. Only after all data have been recorded (and in some
cases, analyzed) do the researchers learn which participants were which. Performing an experiment in
double-blind fashion can greatly lessen the power of preconceived notions or physical cues, such as the
placebo effect, observer bias, and experimenter’s bias, to distort the results by making
researchers/participants behave differently than they would in everyday life. Random assignment of
test subjects to the experimental and control groups are a critical part of any double-blind research
design. The key that identifies the subjects and which group they belonged to is kept by a third party,
and is not revealed to the researchers until the study is over.
Human multitasking is the best performance by an individual of appearing to handle more than one task
at the same time. The term is derived from computer multitasking. An example of multitasking is taking
phone calls while typing an email. Some believe that multitasking can result in time wasted due to
human context switching and apparently causing more errors due to insufficient attention.
Errors in Reading:
One must notice internal details of words and use context to facilitate word recognition. If person has
difficulty noticing internal details, he/she may attempt to only use context, which would lead to a lot of
guessing. If both skills are weak, one may get favoured over the other at random.
Cognitive Behaviour Modification:
CBM has been used to teach children to orchestrate sub-skills better. CBM uses self-instructional skills
to teach a child's executive system how to better allocate resources. This teaching technique uses
modelling, self-verbalization, and self-reinforcement. The teacher acts as a model in performing a task,
and the child is allowed to do the task as the teacher provides verbal instructions. The child is requested
to repeat the task while verbalizing the instructions aloud. The child completes the task while
whispering the instructions. Finally, while self-instructing, the child talks to himself covertly as he does
the task again. When the task is complete the child congratulates himself (sel