THEORETICAL ASPECTS OF INTELLECTUAL DISABILITY - DEFINITION, CLASSIFICATION

: The onset of intellectual disability is marked by impairment of all parts that contribute to an individual's intelligence, such as the functions of socialization, knowledge, speech, and motor function. Intellectual disability is also defined, involving significant limitations in both intellectual functioning and adaptive behavior, which cover many daily social, motor, and practical skills. The most commonly accepted definition of intellectual disability is that provided by AAIDD: “Intellectual disability is a disability characterized by significant reductions in both mental functioning and adaptive behavior, covering many daily social and practical skills. This disability originates before the age of 18.”


Introduction
International statistics show that the number of disabled persons worldwide is rising. World Health Organisation (OMS), in collaboration with World Bank (WB), launched on 09.06.2011 the first world report on disability [11]. Following the studies and research for elaborating the report, it has been shown that over one billion people in the world live with some form of disability; this accounted, at that point, for 15% of the world population. WHO had made available its last statistics in the `70s; back in those times, the Organisation estimated that almost 10% of the world population was impaired. In the WHO report -drafted up in collaboration with the World Bank [14]:it is estimated that in the coming period, disability will be a much bigger problem, as its presence is constantly increasing, mainly due to the aging population and the higher risk of disability among the elderly, as well as the increase in international number of chronically ill patients. The most common diseases caused by it are cardiovascular disease, cancer, mental health problems, and diabetes [13]. In a recent study [3], it is shown that the evidence available concerning the variation between countries in terms of exposure to the determining factors of intellectual disability (such as poverty, malnutrition) suggests presence of mental disability is higher in lower-income countries.
In the European Union (UE), the number of disabled persons is 80 million, accounting for around 15% of the EU population; one of four Europeans has a family member suffering from a disability as specified in Official Journal of the European Union. In Romania -according to the National Authority for the Rights of Disabled Persons, Children, and Adoptions within the Ministry of Labour and Social Protection, through the General Directorates of Social Work and Child Protection, at the level of each county, as well as through the Local Directorates within the sectors of the Bucharest municipality -it is shown that on 20 June 2020, the total number of disabled persons is 853,465 persons. From among them, 97.96% (836.074 persons) are in the care of their families and/or they live independently (non-institutionalised) and 2.04% (17.391 persons) are in public social work residential establishments for the disabled persons (institutionalised) coordinated by the Ministry of Labour and Social Protection (MLSP). According to MLSP, it may be noted that the number of disabled persons in Romania is on a continual rise. After centralising these data, it results that intellectual disability ranks the third, with 124,829 cases, (9,588 of whom children).

Contents
World Health Organisation defines intellectual disability as a deficit of abilities in several fields of development, such as cognitive functioning and behavioural adaptation (WHO, 2018). The term "intellectual disability" refers to a group of developmental conditions affecting the cognitive functioning of a person and, consequently, their capacity to learn and function independent independently [4]. The term "intellectual disability" was agreed by the American Association of Intellectual and Developmental Disabilities (AAIDD) as a deviation from intellectual normality defined by the existence of incomplete intellectual development [1]. Lack of sufficient intellectual development is classified as affecting all functions that contribute to an individual's intellectual development, such as cognitive, language, motor, and social factors, as specified by the World Health Organization [9]. Intellectual disability is also defined as a limitation in both intellectual functioning and adaptive behavior, which includes several language, motor, social and practical skills. At the same time, the term intellectual disability refers to a significant decrease in mental capacities, determines a series of deregulations of the individuals' responses and mechanisms to the everchanging conditions of the environment and to the social co-habitation standards from a certain cultural area, which places a person in a position of incapacity and inferiority, reflected by a situation of disability vis-à-vis other members of the society to which the person belongs [2].
International literature highlights that the notion of "disabilities" expresses incapacity, thus often accompanied by stigma; three types of stigma are identified, as follows: related to physical features, related to mental traits, and related to membership in a group [7]. Focusing the definitions on deficiency or disability it ends up showing that we ignore completely the disabled person's qualities and potential.
World Health Organisation has decided to use three different concepts: • "Impairment" is presented as any temporary or permanent loss or abnormality of a structure or function of the body; this can lead to physiological or psychological disorders.
• "disability" is presented as a barrier or inability to perform an action in the manner or range considered normal for a human being, such as motor disability or visual impairment, etc.; • "disabled" -this is the result of a deficiency or disability that limits or prevents the fulfillment of one or more roles considered normal, depending on the age, sex and social and cultural factors in which the individual lives. The notion of "disable" is more comprehensive and it comprises the social role of the deficient or disabled person, thus being in disadvantage compared to other persons in the concrete case of the person' interaction with their specific social and cultural environment [12].
Regarding the above description, five hypotheses are considered important and basic when applying this definition [5]: • The limitations of the current intellectual and motor functioning must be taken into account in comparison with the social environment typical of the age and culture of the individual.
• Valid assessment takes into account cultural and speech variety, as well as differences in communication, sensory, motor.
• For a person in this situation, the limits are most often present with strengths.
• An essential point of describing the limitations is to create a model of needs.
• With support for every need for a period of time, the functioning of the life of an individual with a mental disability will generally improve. In the current discussions, at an international level, it is predicted that intellectual disability is generated by several factors: genetics, environmental aggression and development vulnerability [6]. Intellectual development disorders have various conditions, which usually occur during the developmental period, characterized by intellectual functioning and behavior to adapt to new situations, well below the average of this population.
The term "disability" was included in international terminology to designate all deviations in the life of an individual. The documents attesting this term are as follows: The Standard Rules of 1993, International Classification of Functioning, adopted by the World Health Assembly in 2001 and subsequently by our country.
In this document, the phrase "disabled children" has the following intentions: • to acknowledge the concept promoted by the aforementioned Classification of the World Health Organisation, in the sense that not all deficiency entails the emergence of disabled and not all conditions (namely, limitations of activity or restrictions of participation); • to introduce the concept of disability, quite common in Romania, too, as well as to cover both terms: "deficiency" and "disabled".
It is universally accepted that a person has a mental disability if we analyze the following situations [ There are a number of atypical features of mental development in children. For example, children may be found who at a younger age fail to perform a series of seemingly normal tasks for their age, risking being categorized as deficient or mentally retarded, and later impressed by the novelty and speed of solutions to tasks received in school curriculum, just as children can be found to give the impression that they are intelligent in their way of reproducing some information, but who can later prove to be truly mentally deficient. Typical for the latter is the case of "learned idiots", who can reproduce complicated texts or can quickly perform arithmetic calculations of great difficulty for an ordinary person, impressing with the style and presentation, but who cannot find effective solutions in situations of adaptation to certain tasks of school, professional or social relevance [5].
Intelligence is generally hereditary. Finding the genetic causes of intellectual disabilities has advanced significantly in the last decade, so a genetic prognosis can now be made in about 45% of children with intellectual disabilities. This adds to wellcharacterized genetic sequelae, such as fragile X syndrome and chromosomal abnormalities, such as Down syndrome (DS). Inbreeding may promote the onset of intellectual disabilities by increasing the likelihood of inheriting diseases rarely encountered in the study population. About 75% of people with severe mental disabilities and 50% of people with mild mental disabilities have an organic or biological basis for their disorder. In such situations, functioning is an interaction of both environmental factors and genetics. Factors such as aggression, poor social status, neglect of parents, physical abuse, limited stimulation and poor parent-child communication are just some of the psychosocial situations that have been shown to be responsible for the mental functioning of individuals in this population [1]. Intellectual disabilities are also influenced by the specificity of the environment and include [10]: • lesions of the Central Nervous System or lack of oxygen; • the presence during pregnancy of infectious diseases: HIV, meningitis, syphilis, etc. ; • lack of proper nutrition by depriving the diet of some elements; The presence of these situations differs depending on the financial situation in each region. Regardless of this situation, the emergence of mental disabilities is still a major research topic for this population.
The presence of specific signs is different depending on the situation and age. Some conditions (eg DS) are obvious immediately after birth or can be determined by specific tests. The later development of peers in the same age population is a specific situation. In some children, after problems in school development (reading problems, writing, basic notions of mathematics) were indeterminate, the installation of mental disability was actually counted. People with mild mental disabilities need help with more complicated activities, such as spending money, choosing the purchases needed for living and for most, the necessary support is possible from their family members, but sometimes the presence of a professional assistant is required other diseases are present. The presence of severe mental disabilities in some children involves continuous help to perform activities necessary for independence; most people need help in their daily lives. Children with profound mental disabilities may not be able to communicate/understand speech, and some may not be able to get the simplest ways to get around, such as walking [11].

Conclusions
The way intellectual disability has been defined has undergone several revisions over the past several decades, as researchers have understood more about the disorder and changed it in response to various social, political and professional situations. [9]. The most widely used definition of intellectual disability is that provided by AAIDD: "Intellectual disability is a disability characterized by significant limitations in both intellectual functioning and adaptive behavior, which cover many everyday social and practical skills. This disability originates before the age of 22" [1]. The literature in this field refers to several synonymous terms to define intellectual disabilities, among which the most common are: mental deficiency, mental disability, mental retardation, mental retardation, oligophrenia, mental retardation, mental insufficiency, mental subnormality, intellectual retardation, mental disability, mental weakness, mental illness, adaptive behavior alteration, etc. [8].