Kirk (1962) was
the first person to use the term "learning disability" and presented
the initial definition as:
A learning disability refers to retardation, disorder, or delayed
development in one or more of the processes of speech, language, reading,
writing, arithmetic, or other school subject resulting from a psychological
handicap caused by a possible cerebral dysfunction and/or emotional or
behavioral disturbances. It is not the result of mental retardation, sensory
deprivation, or cultural factors (Zumeta, 2014).
After Kirk's
conceptualization, several other definitions were presented, but the focus of
all definitions was conceptual and inadequate to explain the operational
features. Therefore, these definitions were not enormously influential for
learning disabilities identification. In 2004, the Individuals with
Disabilities Education Improvement Act defined specific learning disabilities
as:
The term "specific learning disability" means a disorder
in one or more of the basic psychological processes involved in understanding
or using language, spoken or written, which may manifest itself in the
imperfect ability to listen, think, speak, read, spell, or do mathematical
calculations. Such a term includes perceptual disabilities, brain injury,
minimal brain dysfunction, dyslexia, and developmental aphasia. Such a term
does not include a learning problem that is primarily the result of the visual,
hearing, or motor disabilities; of mental retardation; of emotional
disturbance; or environmental, cultural, or economic disadvantage (IDEA 2004,
602.30, Definitions).
As the
presented definitions were insufficient to provide explicit guidelines for the
identification and diagnosis of specific learning disabilities, therefore,
three systems of classification were introduced (a) evaluation through the
criteria of IDEA 2004, (b) Diagnostic and Statistical Manual of Mental Disorders,
2013 and (c) International Classification of Diseases, (2016).
Types
of Specific Learning Disorder
Specific
learning disorders are categorized as dyslexia, dysgraphia, and dyscalculia
based on their characteristics.
Specific
Reading Disorder (Dyslexia)
Dyslexia
is defined as a specific learning disability that has a neurological origin.
This disorder is characterized by difficulties with correct and/or fluent word
recognition and poor decoding and spelling abilities. Deficits in the
phonological component of language are usually unexpected relative to other
cognitive abilities, and the facility of effective classroom instruction cause
these difficulties. These difficulties may lead to reading comprehension
problems and reduced reading experience that can hinder the development of
vocabulary and background knowledge (International Dyslexia Association, 2014).
According to International Dyslexia Association, children with dyslexia may
have one or more of the following symptoms: (a) problem with oral language, (b)
trouble with reading, and (c) problem with written language.
Specific reading disorder is further
divided into four subtypes.
Dysphonetic
Dyslexia
Students with
dysphonetic dyslexia find it difficult to sound out words in a phonological way
hence caused them to be dependent on the semantic and orthographic properties
of words. The neuroanatomical deficits for this problem lie in the left
temporal-parietal areas.
Surface
Dyslexia
Students with
surface dyslexia find it difficult to recognize words in print rapidly and
automatically. The neuroanatomical deficits are in the fusiform gyrus of the
left hemisphere.
Mixed Dyslexia
Mixed dyslexia
is the severest form of dyslexia in which students have reading deficits
determined by impairments in phonological and orthographic processing skills.
Neuroanatomical deficits are in the left temporal-parietal regions, fusiform
gyrus, and angular gyrus.
Comprehension
Deficits
Incomprehension
deficits the difficulty persists in understanding the meaning from print, but
the reading process remains fine. Neuroanatomical problems are in the executive
functioning skills and left dorsolateral prefrontal cortex.
Dysgraphia
Students with
dysgraphia usually have handwriting problems with or without relative spelling
problems. Sometimes these students have only orthographic spelling problems
associated with smooth access to definite spellings in long-term memory.
Consequently, students with dysgraphia have trouble with a written expression
of an idea through writing.
Oral and
Written Language Specific Learning Disability
Students with
this specific learning disability find to have problems with word reading,
spelling, reading comprehension, and written expression of ideas; his causes
deficits in morphological, syntactic awareness, and word retrieval. Hence, it
is both an oral and written language disorder.
Dyscalculia
Students with
dyscalculia find it challenging to learn and perform mathematics. Usually, it
is considered developmental without any observable etiology. It affects the
ability to learn or comprehend mathematics. Dyscalculia is further divided into
developmental dyscalculia, math learning disability, developmental arithmetic
disorder, specific learning disability in mathematics, and mathematics
disability.
Acalculia
The presence of
acquired mathematical difficulties characterizes a student with acalculia. It
usually occurs due to traumatic brain injury or other neurological deficits.
Acalculia is a type of aphasia that causes an inability or loss of ability to
do mathematical tasks. Acalculia is further divided into aphasic acalculia,
visual-spatial acalculia, and anarithmetia. It is considered more severe than
dyscalculia.
Conclusion
The purpose of
defining specific learning disorders and their types is to make the teachers
and parents realize that sometimes students face academic failure due to such
issues. If they find their child or student facing these problems, they should
consult or refer them to a psychologist to evaluate and manage (if needed).
Instead of blaming them (they are doing wrong willingly), the teachers or
parents first make sure that there is no other problem that can cause academic
failure.
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