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Intellectual Disability

Intellectual disability (ID) or general learning disability is a generalized disorder appearing before adulthood, characterized by significantly impaired cognitive functioning and deficits in two or more adaptive behaviors. Intellectual disability is also known as mental retardation (MR)

Mental retardation

Mental retardation(MR) is a generalized disorder appearing before adulthood, characterized by significantly impaired cognitive functioning and deficits in two or more adaptive behaviors. It has historically been defined as an Intelligence Quotient score under 70.Once focused almost entirely on cognition, the definition now includes both a component relating to mental functioning and one relating to individuals' functional skills in their environment. As a result, a person with a below-average intelligence quotient (BAIQ) may not be considered mentally retarded. Syndromic mental retardation is intellectual deficits associated with other medical and behavioral signs and symptoms. Non-Syndromic mental retardation refers to intellectual deficits that appear without other abnormalities.

The terms used to describe this condition are subject to a process called the euphemism treadmill. This means that whatever term is chosen for this condition, it eventually becomes perceived as an insult. The terms mental retardation and mentally retarded were invented in the middle of the 20th century to replace the previous set of terms, which were deemed to have become offensive. By the end of the 20th century, these terms they have come to be widely seen as disparaging and politically incorrect and in need of replacement. The term intellectual disability or intellectually challenged is now preferred by most advocates in most English-speaking countries. Clinically, however, mental retardation is a subtype of intellectual disability, which is a broader concept and includes intellectual deficits that are too mild to properly qualify as mental retardation, too specific (as in specific learning disability), or acquired later in life, through acquired brain injuries or neurodegenerative diseases like dementia. Intellectual disabilities may appear at any age. Developmental disability is any disability that is due to problems with growth and development. This term encompasses many congenital medical conditions that have no mental or intellectual components, although it, too, is sometimes used as a euphemism for MR. Because of its specificity and lack of confusion with other conditions, mental retardation is still the term most widely used and recommended for use in professional medical settings, such as formal scientific research and health insurance paperwork.

Classifying Abilities

These children typically have difficulties with social, communication, and functional academic skills. Children who have a neurological disorder or illness such as encephalitis or meningitis may suddenly show signs of cognitive impairment and adaptive difficulties. Mental Retardation varies in severity. The Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text version (DSM-IV-TR), which is the diagnostic standard for mental health care professionals in the United States, classifies four different degrees of mental retardation: mild, moderate, severe, and profound. These categories are based on the person’s level of functioning.

Mild mental retardation

Approximately 85% of the mentally retarded population is in the mildly retarded category. Their IQ score ranges from 50-70, and they can often acquire academic skills up to about the sixth-grade level. They can become fairly self-sufficient and in some cases live independently, with community and social support.

Moderate mental retardation

About 10% of the mentally retarded population is considered moderately retarded. Moderately retarded persons have IQ scores ranging from 35-55. They can carry out work and self-care tasks with moderate supervision. They typically acquire communication skills in childhood and are able to live and function successfully within the community in such supervised environments as group homes

Severe mental retardation

About 3-4% of the mentally retarded population is severely retarded. Severely retarded persons have IQ scores of 20-40. They may master very basic self-care skills and some communication skills. Many severely retarded individuals are able to live in a group home.

Profound mental retardation

Only 1-2% of the mentally retarded population is classified as profoundly retarded. Profoundly retarded individuals have IQ score under 20-25.They may be able to develop basic self-care and communication skills with appropriate support and training. Their retardation is often caused by an accompanying neurological disorder. Profoundly retarded people need a high-level of structure and supervision

Autism Spectrum Disorder

The autism spectrum or autistic spectrum describes a range of conditions classified as pervasive developmental disorders in the Diagnostic and Statistical Manual of Mental Disorders (DSM). Pervasive developmental disorders include autism, Asperger syndrome, pervasive developmental disorder not otherwise specified (PDD-NOS), childhood disintegrative disorder, and Rett syndrome, although usually only the first three conditions are considered part of the autism spectrum. These disorders are typically characterized by social deficits, communication difficulties, stereotyped or repetitive behaviors and interests, and in some cases, cognitive delays. Although these diagnoses share some common features, individuals with these disorders are thought to be "on the spectrum" because of differences in severity across these domains.

Autism is characterized by delays or abnormal functioning before the age of three years in one or more of the following domains: social interaction; communication; and restricted, repetitive, and stereotyped patterns of behavior, interests, and activities. Social impairments are marked by poor use of nonverbal communication, difficulty in peer relations, lack of social-emotional reciprocity, and lack of shared enjoyment. Communication deficits may include failure to develop speech, use of stereotyped or delayed echolalia, and difficulties maintaining conversations. Social and communication impairments may also cause a lack of symbolic or imaginative play. Restricted and repetitive behaviors may include unusual preoccupations with narrow interests, inflexibility to nonfunctional routines, stereotyped and repetitive mannerisms, and preoccupations with parts of objections.

Asperger syndrome can be distinguished from autism by the lack of delay or deviance in early language development. Additionally, individuals with Asperger syndrome do not have significant cognitive delays. An individual with Asperger syndrome typically demonstrates obsessive interest in a single topic or activity. Other symptoms include repetitive routines or rituals, peculiarities in speech and language, inappropriate affect or social behavior, problems with non-verbal communication, and clumsy or uncoordinated motor movements. Because of these difficulties, individuals with Asperger syndrome often have trouble interacting with others.

PDD-NOS is considered "sub threshold autism" and "atypical autism" because it is often characterized by milder symptoms of autism or symptoms in only one domain (such as social difficulties).Persons with PDD-NOS may demonstrate pervasive deficits in the development of reciprocal social interaction or stereotyped behaviors, but do not meet the criteria for a specific pervasive developmental disorder or other psychological disorders (such as schizophrenia or avoidant personality disorder).


The term "autism spectrum" is often used to describe disorders that are currently classified as pervasive developmental disorders. Pervasive developmental disorders include autism, Asperger syndrome, Childhood disintegrative disorder, Rett syndrome and Pervasive Developmental Disorder Not Otherwise Specified. These disorders are typically characterized by social deficits, communication difficulties, stereotyped or repetitive behaviors and interests, and/or cognitive delays. Although these diagnoses share some common features, individuals with these disorders are thought to be "on the spectrum" because of differences in severity across these domains.

Asperger Syndrome

Asperger syndrome (AS), also known as Asperger's syndrome or Asperger disorder, is an autism spectrum disorder (ASD) that is characterized by significant difficulties in social interaction, alongside restricted and repetitive patterns of behavior and interests. It differs from other autism spectrum disorders by its relative preservation of linguistic and cognitive development. Although not required for diagnosis, physical clumsiness and atypical use of language are frequently reported.

The syndrome is named after the Austrian pediatrician Hans Asperger who, in 1944, studied and described children in his practice who lacked nonverbal communication skills, demonstrated limited empathy with their peers, and were physically clumsy. The modern conception of Asperger syndrome came into existence in 1981 and went through a period of popularization, becoming standardized as a diagnosis in the early 1990s. Many questions remain about aspects of the disorder. For example, there is doubt about whether it is distinct from high-functioning autism (HFA); partly because of this, its prevalence is not firmly established. It has been proposed that the diagnosis of Asperger's be eliminated, to be replaced by a diagnosis of autism spectrum disorder on a severity scale.

The exact cause is unknown. Although research suggests the likelihood of a genetic basis, there is no known genetic etiology and brain imaging techniques have not identified a clear common pathology. There is no single treatment, and the effectiveness of particular interventions is supported by only limited data. Intervention is aimed at improving symptoms and function. The mainstay of management is behavioral therapy, focusing on specific deficits to address poor communication skills, obsessive or repetitive routines, and physical clumsiness. Most children improve as they mature to adulthood, but social and communication difficulties may persist. Some researchers and people with Asperger's have advocated a shift in attitudes toward the view that it is a difference, rather than a disability that must be treated or cured.

Heller's Syndrome

Childhood disintegrative disorder (CDD), also known as Heller's syndrome and disintegrative psychosis, is a rare (1.7 cases per 100,000[1]) condition characterized by late onset (>3 years of age) of developmental delays in language, social function, and motor skills. Researchers have not been successful in finding a cause for the disorder.

CDD has some similarity to autism, and is sometimes considered a low-functioning form of it, but an apparent period of fairly normal development is often noted before a regression in skills or a series of regressions in skills. Many children are already somewhat delayed when the disorder becomes apparent, but these delays are not always obvious in young children.

The age at which this regression can occur varies, and can be from age 2-10 with the definition of this onset depending largely on opinion.

Regression can be very sudden, and the child may even voice concern about what is happening, much to the parent's surprise. Some children describe or appear to be reacting to hallucinations, but the most obvious symptom is that skills apparently attained are lost. This has been described by many writers as a devastating condition, affecting both the family and the individual's future. As is the case with all pervasive developmental disorder categories, there is considerable controversy about the right treatment for CDD.

The syndrome was originally described by Austrian educator Theodor Heller in 1908, 35 years before Leo Kanner and Hans Asperger described autism, but it has not been officially recognised until recently. Heller used the name dementia infantilis for the syndrome.

Pervasive Development Disorder

The diagnostic category pervasive developmental disorders (PDD), as opposed to specific developmental disorders (SDD), refer to a group of five disorders characterized by delays in the development of multiple basic functions including socialization and communication. The pervasive developmental disorders are:

Pervasive developmental disorder not otherwise specified (PDD-NOS), which includes atypical autism, and is the most common;

  • Autism, the best-known
  • Asperger syndrome
  • Rett syndrome and
  • Childhood disintegrative disorder (CDD).

The first three of these disorders are commonly called the autism spectrum disorders; the last two disorders are much rarer, and are sometimes placed in the autism spectrum and sometimes not.

Parents may note symptoms of PDD as early as infancy and typically onset is prior to three years of age. PDD itself does not affect.

There is a division among doctors on the use of the term PDD. Many use the term PDD as a short way of saying PDD-NOS. Others use the general category label of PDD because they are hesitant to diagnose very young children with a specific type of PDD, such as autism. Both approaches contribute to confusion about the term, because the term PDD actually refers to a category of disorders and is not a diagnostic label.

Retts Syndrome

Rett syndrome is a neurodevelopmental disorder of the grey matter of the brain] that almost exclusively affects females. The clinical features include small hands and feet and a deceleration of the rate of head growth (including microcephaly in some). Repetitive hand movements, such as wringing and/or repeatedly putting hands into the mouth, are also noted. People with Rett syndrome are prone to gastrointestinal disorders and up to 80% have seizures. They typically have no verbal skills, and about 50% of individuals affected are not ambulatory. Scoliosis, growth failure, and constipation are very common and can be problematic.

The signs of this disorder are most easily confused with those of Angelman syndrome, cerebral palsy and autism.

Some argue that it is misclassified as an autism spectrum disorder, just as it would be to include such disorders as fragile X syndrome, tuberous sclerosis, or Down syndrome where one can see autistic features. However, it has been suggested that it be removed from the DSM-5, because it has a specific etiology.

It has also been argued that Rett Syndrome is in fact a neurodegenerative condition as opposed to a neurodevelopmental condition. This was shown by the fact that mice with induced Rett Syndrome can have their neurons completely restored and a normal phenotype by adding the MECP2 gene back to their genome. This information has also helped lead to further studies in curing or treating the disorder.

It was first described by Austrian pediatrician Andreas Rett in 1966.

Learning Disability

What are learning disabilities?

Learning disabilities, or learning disorders, are an umbrella term for a wide variety of learning problems. A learning disability is not a problem with intelligence or motivation. Kids with learning disabilities aren’t lazy or dumb. In fact, most are just as smart as everyone else. Their brains are simply wired differently. This difference affects how they receive and process information.

Simply put, children and adults with learning disabilities see, hear, and understand things differently. This can lead to trouble with learning new information and skills, and putting them to use. The most common types of learning disabilities involve problems with reading, writing, math, reasoning, listening, and speaking.

Children with learning disabilities can, and do, succeed

It can be tough to face the possibility that your child has a learning disorder. No parents want to see their children suffer. You may wonder what it could mean for your child’s future, or worry about how your kid will make it through school. Perhaps you’re concerned that by calling attention to your child's learning problems he or she might be labeled "slow" or assigned to a less challenging class.

But the important thing to remember is that most kids with learning disabilities are just as smart as everyone else. They just need to be taught in ways that are tailored to their unique learning styles. By learning more about learning disabilities in general, and your child’s learning difficulties in particular, you can help pave the way for success at school and beyond.

Signs and symptoms of learning disabilities and disorders

If you’re worried, don’t wait

If you suspect that your child's learning difficulties may require special assistance, please do not delay in finding support. The sooner you move forward, the better your child's chances for reaching his or her full potential.

Learning disabilities look very different from one child to another. One child may struggle with reading and spelling, while another loves books but can’t understand math. Still another child may have difficulty understanding what others are saying or communicating out loud. The problems are very different, but they are all learning disorders.

It’s not always easy to identify learning disabilities. Because of the wide variations, there is no single symptom or profile that you can look to as proof of a problem. However, some warning signs are more common than others at different ages. If you’re aware of what they are, you’ll be able to catch a learning disorder early and quickly take steps to get your child help.

The following checklist lists some common red flags for learning disorders. Remember that children who don’t have learning disabilities may still experience some of these difficulties at various times. The time for concern is when there is a consistent unevenness in your child’s ability to master certain skills.

Preschool signs and symptoms of learning disabilities

  • Problems pronouncing words
  • Trouble finding the right word
  • Difficulty rhyming
  • Trouble learning the alphabet, numbers, colors, shapes, days of the week
  • Difficulty following directions or learning routines
  • Difficulty controlling crayons, pencils, and scissors or coloring within the lines
  • Trouble with buttons, zippers, snaps, learning to tie shoes

Grades K-4 signs and symptoms of learning disabilities

  • Trouble learning the connection between letters and sounds
  • Unable to blend sounds to make words
  • Confuses basic words when reading
  • Consistently misspells words and makes frequent reading errors
  • Trouble learning basic math concepts
  • Difficulty telling time and remembering sequences
  • Slow to learn new skills

Grades 5-8 signs and symptoms of learning disabilities

  • Difficulty with reading comprehension or math skills
  • Trouble with open-ended test questions and word problems
  • Dislikes reading and writing; avoids reading aloud
  • Spells the same word differently in a single document
  • Poor organizational skills (bedroom, homework, desk is messy and disorganized)
  • Trouble following classroom discussions and expressing thoughts aloud
  • Poor handwriting

Paying attention to developmental milestones can help you identify learning disorders

Paying attention to normal developmental milestones for toddlers and preschoolers is very important. Early detection of developmental differences may be an early signal of a learning disability and problems that are spotted early can be easier to correct.

A developmental lag might not be considered a symptom of a learning disability until your child is older, but if you recognize it when your child is young, you can intervene early. You know your child better than anyone else does, so if you think there is a problem, it doesn't hurt to get an evaluation. You can also ask your pediatrician for a developmental milestones chart.

Problems with reading, writing, and math

Learning disabilities are often grouped by school-area skill set. If your child is in school, the types of learning disorders that are most conspicuous usually revolve around reading, writing, or math.

Learning disabilities in reading (dyslexia)

There are two types of learning disabilities in reading. Basic reading problems occur when there is difficulty understanding the relationship between sounds, letters and words. Reading comprehension problems occur when there is an inability to grasp the meaning of words, phrases, and paragraphs.

Signs of reading difficulty include problems with:

  • Letter and word recognition
  • Understanding words and ideas
  • Reading speed and fluency
  • General vocabulary skills

Learning disabilities in math (dyscalculia)

Learning disabilities in math vary greatly depending on the child’s other strengths and weaknesses. A child’s ability to do math will be affected differently by a language learning disability, or a visual disorder or a difficulty with sequencing, memory or organization.

A child with a math–based learning disorder may struggle with memorization and organization of numbers, operation signs, and number “facts” (like 5+5=10 or 5x5=25). Children with math learning disorders might also have trouble with counting principles (such as counting by 2s or counting by 5s) or have difficulty telling time.

Learning disabilities in writing (dysgraphia)

Learning disabilities in writing can involve the physical act of writing or the mental activity of comprehending and synthesizing information. Basic writing disorder refers to physical difficulty forming words and letters. Expressive writing disability indicates a struggle to organize thoughts on paper.

Symptoms of a written language learning disability revolve around the act of writing. They include problems with:

  • Neatness and consistency of writing
  • Accurately copying letters and words
  • Spelling consistency
  • Writing organization and coherence

Other types of learning disabilities and disorders

Reading, writing, and math aren’t the only skills impacted by learning disorders. Other types of learning disabilities involve difficulties with motor skills (movement and coordination), understanding spoken language, distinguishing between sounds, and interpreting visual information.

Learning disabilities in motor skills (dyspraxia)

Motor difficulty refers to problems with movement and coordination whether it is with fine motor skills (cutting, writing) or gross motor skills (running, jumping). A motor disability is sometimes referred to as an “output” activity meaning that it relates to the output of information from the brain. In order to run, jump, write or cut something, the brain must be able to communicate with the necessary limbs to complete the action.

Signs that your child might have a motor coordination disability include problems with physical abilities that require hand-eye coordination, like holding a pencil or buttoning a shirt.

Learning disabilities in language (aphasia/dysphasia)

Language and communication learning disabilities involve the ability to understand or produce spoken language. Language is also considered an output activity because it requires organizing thoughts in the brain and calling upon the right words to verbally explain something or communicate with someone else.

Signs of a language-based learning disorder involve problems with verbal language skills, such as the ability to retell a story and the fluency of speech, as well as the ability to understand the meaning of words, parts of speech, directions, etc.

Auditory and visual processing problems: the importance of the ears and eyes

The eyes and the ears are the primary means of delivering information to the brain, a process sometimes called “input.” If either the eyes or the ears aren’t working properly, learning can suffer.

Auditory processing disorder – Professionals may refer to the ability to hear well as “auditory processing skills” or “receptive language.” The ability to hear things correctly greatly impacts the ability to read, write and spell. An inability to distinguish subtle differences in sound, or hearing sounds at the wrong speed make it difficult to sound out words and understand the basic concepts of reading and writing.

Visual processing disorder – Problems in visual perception include missing subtle differences in shapes, reversing letters or numbers, skipping words, skipping lines, misperceiving depth or distance, or having problems with eye–hand coordination. Professionals may refer to the work of the eyes as “visual processing.” Visual perception can affect gross and fine motor skills, reading comprehension, and math.

Other disorders that make learning difficult

Difficulty in school doesn’t always stem from a learning disability. Anxiety, depression, stressful events, emotional trauma, and other conditions affecting concentration make learning more of a challenge. In addition, ADHD and autism sometimes co-occur or are confused with learning disabilities.

ADHD – Attention deficit hyperactivity disorder (ADHD), while not considered a learning disability, can certainly disrupt learning. Children with ADHD often have problems sitting still, staying focused, following instructions, staying organized, and completing homework.

Autism – Difficulty mastering certain academic skills can stem from pervasive developmental disorders such as autism and Asperger’s syndrome. Children with autism spectrum disorders may have trouble communicating, reading body language, learning basic skills, making friends, and making eye contac.

Source: e-Saadhya - Adaptable and Accessible e-Learning, C-DAC

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