Intellectual Disability: Definition And Types

People with intellectual disabilities have fewer cognitive resources or less developed cognitive resources than would be expected, taking into account their chronological age. This would increase the cost of learning, in addition to having to make a greater effort to communicate in some contexts and with certain messages. This type of disability is usually identified before the age of 18 and affects 1% of the world’s population.

But it is important to note that intellectual disability is not a mental illness, but a developmental disorder. All people with this type of disability are essentially like us: they have their own dreams, interests, tastes and preferences. In this sense, it is important not to stigmatize the disease and for that, what better way than to know a little more about it!

Intellectual functioning and adaptive behavior

Intellectual disability can be of different degrees and each of them involves difficulties. It manifests as problems with reasoning, planning, problem solving, abstract thinking, and learning. All this due to a slow and incomplete acquisition of cognitive skills.

Their adaptive capacities can also be very limited, both conceptually, socially and practically. Therefore, their ability to express themselves linguistically or their reading and writing are poorly developed, as well as their sense of responsibility or self-esteem.

Faced with daily activities, such as cleaning, personal care or preparing food, they can present a variable level of autonomy depending on the degree of disability. In instrumental or mechanical activities there is also this variability.

Affecting your health and social interactions

This disability can be accompanied by certain alterations related to physical and mental health. In turn, all of this can affect the rest of the dimensions.

Some syndromes that can occur with intellectual disability are: Rett, Dravet, Prader-Willi, Down, Asperger’s, fragile X or Martin and Bell’s syndrome. Likewise, it has a higher prevalence in diseases such as obesity, diabetes, HIV and STDs or dementia.

Also their communication, interaction or social participation are affected. Their intellectual and adaptive limitations make it impossible for this person to participate in the life of their community in a normal way. This harms all their areas: home, school, work and in their leisure time.

The role of the IQ

IQ alone is not a sufficient criterion for making a diagnosis of intellectual disability. In addition to defining intelligence quantitatively, it is necessary to make a more in-depth evaluation of the person’s intellectual functioning.

IQ is understood as the relationship between mental age and chronological age of the person. The first refers to the age that corresponds to him according to his intellectual development. That is, how much does he perform intellectually compared to the average level of his reference group. The chronological age is the biological one.

It is considered that there is some intellectual disability if the IQ is less than 70. The other extreme, giftedness, is diagnosed when this index is above 130. It is precisely the IQ that serves to classify the degree of this disability.

Possible causes

Among the main causes of intellectual disability are:

• Genetic conditions Presence of abnormal genes inherited from parents, errors when genes are combined, etc.
• Problems during pregnancy. When the baby does not achieve optimal development in the womb, it can trigger disability. It also includes the consumption of substances such as alcohol or contracting a disease such as rubella.
• Problems at birth. Lack of oxygen during birth is one of the most frequent cases.
• Health problems. Diseases such as meningitis can be the cause of disability. As well as extreme malnutrition.

Types of intellectual disability

According to the DSM-IV it is classified as mild, moderate, severe and profound.

Mild (CI 50-55 to 70)

85% of people with disabilities have a mild disability.

• Conceptual domain: low impairment of abstract thinking, functional abilities, cognitive flexibility, and short-term memory.
• Social domain: immature social interactions, which increases the risk that the person with a disability will be manipulated.
• Practical domain : it is necessary that they have supervision, guidance and assistance when carrying out tasks of their daily life. This help is very important especially in stressful situations.
• They are often no different from other children without this disability until they are older.

Moderate (IQ 35-40 to 50-55)

10% of people with disabilities have a moderate disability.

• Conceptual mastery: require ongoing assistance to complete daily activities. Sometimes it is even necessary for other people to assume some of their responsibilities. They are people who with moderate supervision are capable of acquiring skills for their own personal care. They can perform jobs that require no qualification or are semi-skilled, but always with supervision.

• Social domain : when communicating verbally, their language is less rich and complex than that of people without disabilities. This means that they cannot correctly interpret some social keys and that they have problems creating new relationships.
• Practical mastery: with continued support and instruction they can develop certain skills and abilities.

Severe (CI 20-25 to 35-40)

3-4% of people with disabilities have severe disabilities.

• Conceptual domain: very limited, especially with numerical concepts. The support has to be important, constant and in many areas.
• Social domain: their oral language is very elementary, their sentences are grammatically simple, and their vocabulary is very limited. Their communications are very simple, they are limited to the here and now.

• Practical domain: supervision must be constant for all the tasks that have to be carried out in daily life.

Deep (CI 20-25)

Although they are a minority (1% -2%), most of these people have an identified neurological disease and explain their disability.

• Conceptual mastery: its deficit is manifest. They only consider the physical world and non-symbolic processes. With instructions, they can acquire certain visuospatial skills, such as pointing. Associated motor and sensory difficulties often prevent functional use of objects.
• Social domain: poor understanding of verbal and gestural communication. His way of expressing himself is very basic, simple and mostly non-verbal.
• Practical domain: the patient is totally dependent in all areas. Only if there are no motor or sensory impairments will he be able to participate in certain basic activities.

The role of institutions seems essential if we want to create an easier and more accessible environment for people with intellectual disabilities. If not, other environmental limitations will be added to the limitations that these people already present.  In any case, what we must never forget is that before disability goes the person, goes the person. Someone with feelings, just like us, someone with dreams, like us, and someone with many things to contribute to others, just like us.