Intellectual Disability: Definition And Types

People with intellectual disabilities have fewer cognitive resources or less developed cognitive resources in relation to their age. This increases the efforts in the process of learning and communication in certain contexts and to convey certain messages. This form of disability is usually diagnosed before the age of 18 and affects 1% of the world population.

It is important to emphasize that intellectual disability is not a mental illness but a developmental disorder. The subject in question has dreams, interests, tastes and preferences like everyone else. It is important not to stigmatize the disease and, for this, it is better to know it better!

Intellectual functioning and adaptive behavior

Intellectual disability can be of different degrees and each of them implies difficulties. It manifests itself with problems of reasoning and planning, difficulties in solving problems, in abstract thinking and in learning; all this is due to a slow and incomplete acquisition of cognitive skills.

The adaptive capacities of the individual with intellectual disabilities can be very limited, from a conceptual, social and practical point of view.  His ability to express himself linguistically or his reading and writing are underdeveloped, as are his sense of responsibility or his self-esteem.

Faced with daily activities, such as tidying up, taking care of oneself or preparing food, it can present a variable level of autonomy, depending on the degree of delay. This variability is also present with regard to instrumental or mechanical activities.

Conditioning of health and social interactions

Intellectual disability  can be accompanied by alterations related to physical and mental health.  In turn, all of this can impact other dimensions.

Some syndromes that can occur with intellectual disability are Rett, Dravet, Prader-Willi, Down, Asperger, Fragile X, or Martin-Bell syndrome. Furthermore, the subject is more prone to suffering from diseases such as obesity, diabetes, HIV and STDs or dementia.

The person’s communication, interaction or social participation are also compromised. In fact, his intellectual and adaptive limitations make normal participation in the life of his community impossible. This  affects all its areas: home, school, work and free time.

The role of the IQ

The IQ by itself is not a sufficient criterion for making a diagnosis of intellectual disability. In addition to quantitatively defining intelligence, it is necessary to make a deeper assessment of the person’s intellectual functioning .

IQ is understood as the relationship that exists between a person’s mental and chronological age .  The first refers to the age that corresponds to her according to her intellectual development. In other words, how much it makes intellectually compared to the average level of its reference group. The chronological age is the biological one.

It is estimated that there is a certain intellectual disability if the IQ is less than  70.  At the other extreme we speak of a gifted person, when this index is above 130. It is precisely the IQ that allows us to classify the degree of intellectual disability .

Degrees of intellectual disability

According to the DSM-IV, intellectual disability can be classified as mild, moderate, severe and profound.

Mild (IQ 50-55 to 70)

85% of people with intellectual disabilities have it in a mild form.

• Conceptual domain:  abstract thinking, functional skills, cognitive flexibility and short-term memory are hardly compromised.
• Social domain: immature social interactions,  this increases the risk of the person with disability being manipulated.
• Practical domain : it is necessary that she is supervised, oriented and assisted to carry out tasks of her daily life. This help is very important especially in stressful situations.

This disability is often not noticed during childhood.

Moderate (IQ 35-40 to 50-55)

10% of people with intellectual disabilities have it in a moderate form.

• Conceptual domain: They need continuous assistance to complete daily activities. Sometimes it is necessary for other people to take on some of their responsibilities. They are people who, with moderate supervision, can acquire the skills necessary to take care of themselves. They can do jobs that do not require qualifications or that are semi-skilled, but always with supervision.
• Social domain : when they have to communicate verbally, their language is less rich and complex. This means that they cannot correctly interpret some social codes and have problems establishing new relationships.
• Practical domain:  With continued support and education they can develop certain skills and abilities.

Severe (IQ 20-25 to 35-40)

3-4% of people with intellectual disabilities have it in severe form.

• Conceptual domain:  very limited, especially as regards numerical concepts. Support must be important, constant and from many points of view.
• Social domain:  oral language is very basic, sentences are grammatically simple and vocabulary very limited. Their communications are very basic, they are limited to the here and now.
• Practical domain:  supervision must be constant for all the tasks they have to perform in daily life.

Deep (IQ 20-25)

Although they are a minority (1% -2%),  the majority of these people have a neurological disease  which explains their intellectual disability.

• Conceptual domain: the deficit is evident. They only consider the physical world and non-symbolic processes. Through instruction, they can acquire certain visual-spatial skills, such as pointing. The motor and sensory difficulties associated with the disorder usually prevent the functional use of objects.

• Social domain:  precarious understanding of verbal and gestural communication. Their way of expressing themselves is very basic, simple and purely non-verbal.
• Practical domain:  the patient is completely dependent, in all areas. Only in the absence of motor or sensory damage will he be able to participate in certain basic activities.

The role of institutions becomes essential if we want to create a simpler and more accessible context for people with intellectual disabilities. Otherwise, to the limits that these people already have in themselves, other environmental ones will be added.  In any case,  we must never forget that before the disability comes the person  with feelings common to all, with dreams and a lot to give to others.