In broad terms, the phrase learning disability covers any of a range of conditions that affect a person's ability to learn new information. These conditions all affect the brain in some fashion. The most common causes are:
defects or errors in brain structure
lack of communication between various parts of the brain
incorrect quantities of various neurotransmitters, or problems in the brain's use of these transmitters
common neurotransmitter problems include insufficient dopamine, improper serotonin regulation, and excessive dopamine reuptake where emitting neurons reabsorb too much dopamine after releasing them to communicate with other neurons (also implicated in depression).
People born with severe learning disability and with an IQ lower than 70 are usually characterised as being mentally retarded or Mentally deficient.
Ultimately caused by an extra chromosome in the genetic makeup of the sufferer. One of the primary consequences of the extra chromosome is mild to severe mental retardation. Other genetic conditions with similar consequences include Trisomy 13 and Fragile X Syndrome.
This condition has several forms in varying degrees of severity. The three primary forms are
difficulty in phonetic mapping, where sufferers have difficulty with matching various orthographic representations to specific sounds
difficulty with spatial orientation, which is stereotyped in the confusion of the letters <b> and <d>, as well as other pairs. In its severest form, <b> <d> <g> and <q>, all distinguished primarily by orientation in handwriting, look identical to the dyslexic
difficulty with sequential ordering, such that a person can see a combination of letters and recognize what word it corresponds to with the help of phonetic mapping, but cannot properly sequence the letters when spelling words.
Dyslexia has obvious effects on the ability to learn to read and/or write, as well as more subtle effects on processing visual information
Language-processing disorders
These are poorly studied, but have clear effects on learning. Effects can be semantic, syntactic or analytical, or can resemble aphasias.
Some people have difficulty with planning, sequencing, using inductive logic, or with verbal expression. All can interfere with learning, at both the input and output phases of the process.
AD(H)D sufferers have difficulty in intiating and maintaining concentration. The underlying neurological causes are not always clear. It also appears that many persons labeled as ADD/ADHD either suffer from other problems, or have not had the thorough neruological analysis needed to help manage their condition.
A condition of the elderly, in which the ability to retain new information is lost. As the condition progresses, the patient begins losing lifelong memories, with the most recent to go first. Eventually, they often regress to childhood, and have such poor memory that they cannot perform simple tasks such as walking from one room to another because they forget where they are going en route.
While not a true learning disability, it affects the ability to perceive visual information. When such information is presented in a way that is confusing to the color-blind, learning is compromised.
Physical handicaps can also impede learning when proper accommodations are not made.
Blindness interferes with the ability to process visual information, so information must be presented in tactile or auditory form to be learnt.
Deafness and hearing impairment interfere with the ability to process auditory information. Information presented in auditory format is meaningless to the deaf, and not properly perceived by the hearing impaired. Learning occurs best when accommodation is made by providing visual and tactile means for acquiring information, as well as providing Sign Language interpreters where needed.
In the United States and Canada, the term learningdisability is used to refer to psychological and neurological conditions that affect a person's communicative capacities and potential to be taught effectively.
Learningdisabilities are usually identified by school psychologists through testing of intelligence, academics and processes of learning.
LearningDisabilities, Dyslexia, and Vision: A Subject Review A report from American Academy Of Pediatrics reporting the complete lack of evidence for a link between visual problems and learning difficulties.
Learningdisabilities are present in at least 10 percent of the population.
Interestingly, there is no clear and widely accepted definition of "learningdisabilities." Because of the multidisciplinary nature of the field, there is ongoing debate on the issue of definition, and there are currently at least 12 definitions that appear in the professional literature.
The primary characteristic of a learningdisability is a significant difference between a child's achievement in some areas and his or her overall intelligence.
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