Subaverage intellectual ability that is present from birth or infancy and is manifested by abnormal development, learning difficulties, and problems in social adjustment. A standardized intelligence test is a common method of identification. Individuals with IQ scores of 53–70 are usually classified as having mild intellectual disability and are able to learn academic and prevocational skills with some special education. Those with scores of 36–52 are classified as having moderate intellectual disability and are able to learn functional academic skills and undertake semiskilled work under supervised conditions. Those in the severe (21–35) and profound (below 21) ranges require progressively more supervision or full-time custodial care. Intellectual disability can be caused by genetic disorders (such as Down syndrome), infectious diseases (such as meningitis), metabolic disorders, poisoning from lead, radiation, or other toxic agents, injuries to the head, and malnutrition.
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Developmental disability is a term used to describe life-long disabilities attributable to mental and/or physical or combination of mental and physical impairments, manifested prior to age twenty-two. The term is used most commonly in the United States to refer to disabilities affecting daily functioning in three or more of the following areas:
The term first appeared in U.S. law in 1970, when Congress used the term to describe the population of individuals who had historically been placed in state institutions, in its effort to improve conditions in these dehumanizing facilities (P.L. 91-517, “The Developmental Disabilities Services and Facilities Construction Act of 1970”). The law has since been amended many times, and now calls for the full community inclusion and self-determination of people with developmental disabilities (P.L. 106-402).
Frequently, people with mental retardation, cerebral palsy, autism spectrum disorder, various genetic and chromosomal disorders such as Down's syndrome and Fragile X syndrome, and Fetal Alcohol Spectrum Disorder are described as having developmental disabilities. This use of the term is synonymous with the use of the term learning disability in the United Kingdom, and intellectual disability in Australia, Europe, Canada and elsewhere. Cognitive disability is also used synonymously in some jurisdictions.
Developmental disabilities are usually classified as severe, profound, moderate or mild, as assessed by the individual's need for supports, which may be lifelong.
Developmental disabilities affect between 1 and 2% of the population in most western countries, although many government sources acknowledge that statistics are flawed in this area. The worldwide proportion of people with developmental disabilities is believed to be approximately 1.4%. It is twice as common in males as in females, and some researchers have found that the prevalence of mild developmental disabilities is likely to be higher in areas of poverty and deprivation, and among people of certain ethnicities.
These problems are exacerbated by difficulties in diagnosis of mental health issues, and in appropriate treatment and medication, as for physical health issues..
Lack of education, lack of self-esteem and self-advocacy skills, lack of understanding of social norms and appropriate behaviour and communication difficulties are strong contributing factors to the high incidence of abuse among this population.
In addition to abuse from people in positions of power, peer abuse is recognised as a significant, if misunderstood, problem. Rates of criminal offending among people with developmental disabilities are also disproportionately high, and it is widely acknowledged that criminal justice systems throughout the world are ill-equipped for the needs of people with developmental disabilities (as both perpetrators and victims of crime).
Some people with developmental disabilities exhibit challenging behaviour, defined as "culturally abnormal behaviour(s) of such intensity, frequency or duration that the physical safety of the person or others is placed in serious jeopardy, or behaviour which is likely to seriously limit or deny access to the use of ordinary community facilities. Common types of challenging behaviour include self-injurious behaviour (such as hitting, headbutting, biting), aggressive behaviour (such as hitting others, screaming, spitting, kicking), inappropriate sexualised behaviour (such as public masturbation or groping), behaviour directed at property (such as throwing objects and stealing) and stereotyped behaviours (such as repetitive rocking, echolalia or elective incontinence).
Challenging behaviour in people with developmental disabilities may be caused by a number of factors, including biological (pain, medication, the need for sensory stimulation), social (boredom, seeking social interaction, the need for an element of control, lack of knowledge of community norms, insensitivity of staff and services to the person's wishes and needs), environmental (physical aspects such as noise and lighting, or gaining access to preferred objects or activities), psychological (feeling excluded, lonely, devalued, labelled, disempowered, living up to people's negative expectations) or simply a means of communication. A lot of the time, challenging behaviour is learned and brings rewards and it is very often possible to teach people new behaviours to achieve the same aims.
Experience and research suggests that what professionals call 'challenging behaviour' is often a reaction to the challenging environments that services create around people with developmental disabilities, and a method of communicating dissatisfaction with the failure of services to listen for what kind of life makes most sense to the person, especially where services deliver lifestyles and ways of working that are centred on what suits the service and it's staff rather than what suits the person.
The movement towards individualism in the 18th and 19th centuries, and the opportunities afforded by the Industrial Revolution, led to housing and care using the asylum model. People were placed by, or removed from, their families (usually in infancy) and housed in large institutions (of up to 3,000 people, although some institutions were home to many more, such as the Philadelphia State Hospital in Pennsylvania which housed 7,000 people through the 1960s), many of which were self-sufficient through the labour of the residents.
Some of these institutions provided a very basic level of education (such as differentiation between colours and basic word recognition and numeracy), but most continued to focus solely on the provision of basic needs. Conditions in such institutions varied widely, but the support provided was generally non-individualised, with aberrant behaviour and low levels of economic productivity regarded as a burden to society. Heavy tranquilisation and assembly line methods of support (such as 'birdfeeding' and cattle herding) were the norm, and the medical model of disability prevailed. Services were provided based on the relative ease to the provider, not based on the human needs of the individual.
Ignoring the prevailing attitude, Civitans adopted service to the developmentally disabled as a major organizational emphasis in 1952. Their earliest efforts included workshops for special education teachers and daycamps for disabled children, all at a time when such training and programs were almost nonexistent. The segregation of people with developmental disabilities wasn't widely questioned by academics or policy-makers until the 1969 publication of Wolf Wolfensberger's seminal work "The Origin and Nature of Our Institutional Models", drawing on some of the ideas proposed by SG Howe a hundred years earlier. This book posited that society characterises people with disabilities as deviant, sub-human and burdens of charity, resulting in the adoption of that 'deviant' role. Wolfensberger argued that this dehumanisation, and the segregated institutions that result from it, ignored the potential productive contributions that all people can make to society. He pushed for a shift in policy and practice that recognised the human needs of "retardates" and provided the same basic human rights as for the rest of the population.
The publication of this book may be regarded as the first move towards the widespread adoption of the social model of disability in regard to these types of disabilities, and was the impetus for the development of government strategies for desegregation. Successful lawsuits against governments and an increasing awareness of human rights and self-advocacy also contributed to this process, resulting in the passing in the US of the Civil Rights of Institutionalized Persons Act in 1980.
From the 1960s to the present, most states have moved towards the elimination of segregated institutions. Along with the work Wolfensberger and others including Gunnar and Rosemary Dybwad, a number of scandalous revelations around the horrific conditions within state institutions created public outrage led to change to a more community-based method of providing services. By the mid-1970s, most governments had committed to de-institutionalisation, and had started preparing for the wholesale movement of people into the general community, in line with the principles of normalization. In most countries, this was essentially complete by the late 1990s, although the debate over whether or not to close instiutions persists in some states, including Massachusetts.
It could be argued that we still have a very long way to go before people with such disabilities are seen as full citizens of society. Person Centred Planning and Person Centred Approaches are seen as methods of addressing the continued labelling and exclusion of socially devalued people, such as people with a developmental disability label, encouraging a focus on the person as someone with capacities and gifts, as well as support needs.
Education and training opportunities for people with developmental disabilities have expanded greatly in recent times, with many governments mandating universal access to educational facilities, and more students moving out of special schools and into mainstream classrooms with support.
Post-secondary education and vocational training is also increasing for people with these types of disabilities, although many programs offer only segregated "access" courses in areas such as literacy, numeracy and other basic skills. Legislation (such as the UK's Disability Discrimination Act 1995) requires educational institutions and training providers to make 'reasonable adjustments' to curriculum and teaching methods in order to accommodate the learning needs of students with disabilities, wherever possible. See also Intensive interaction.
In the United States a support worker is known as a Direct Support Professional (DSP). The DSP works in assisting the individual with their ADLs and also acts as an advocate for the individual with a developmental disability, in communicating their needs, self expression and goals.
Supports of this type also include assistance to identify and undertake new hobbies or to access community services (such as education), learning appropriate behaviour or recognition of community norms, or with relationships and expanding circles of friends. Most programs offering at-home and community support are designed with the goal of increasing the individual's independence, although it is recognised that people with more severe disabilities may never be able to achieve full independence in some areas of daily life.
Workers with developmental disabilities have historically been paid less for their labour than those in the general workforce, although this is gradually changing with government initiatives, the enforcement of anti-discrimination legislation and changes in perceptions of capability in the general community.
Traditional day centres were based on the principles of occupational therapy, and were created as respite for family members caring for their loved ones with disabilities. This is slowly changing, however, as programs offered become more skills-based and focused on increasing independence.
Wishart, G.D. (2003) The Sexual Abuse of People with Learning Difficulties: Do We Need A Social Model Approach To Vulnerability?, Journal of Adult Protection, Volume 5 (Issue 3)
Educating Psychiatric Residents in Intellectual Disability: Does Exposure during Residency Affect Attitudes toward Persons with Intellectual Disability?
Oct 01, 2008; We evaluated the attitudes of psychiatric resident graduates and current psychiatry residents, regarding community living for...