Intellectual Disability in Children: Know the Signs

Intellectual Disability in Children: Know the Signs

Intellectual Disability

Intellectual disability (ID), formerly called as mental retardation, is a type of developmental disability, in which individuals have certain limitations in their intellectual functioning and adaptive behavior. People with ID have difficulty learning, communicating, solving problems on their own along with poorly developed social skills. 

Signs of Intellectual Disability

Limited mental ability and deficient adaptive functioning are two diagnostic criteria used to identify intellectual disabilities in people.

An IQ test can be carried out to measure an individual's mental ability. Many problems are caused by severely limited mental abilities. First, learning becomes difficult. Second, making wise decisions becomes difficult, which means that children with ID are often unable to judge properly. Third, solving problems becomes difficult, and fourth, children become more prone to victimization.

Deficient adaptive functioning is the second diagnostic criterion. Adaptive functioning means whether the child possesses the skills to independently and safely live in a socially responsible manner. The essential skill sets are conceptual skills, social skills, and practical skills. Conceptual skills are related to mathematics along with language, literacy, self-direction, and time. Children can get along with others with the help of social skills. Having practical skills means that individuals are able to care for themselves, maintain their overall health, safety, and do basic tasks. 

In short, a broad range of difficulties may be experienced by people with intellectual disabilities, such as employment problems, self-direction, health, safety, education, independent living, self care, interpersonal relationships, and access to community resources.

The signs of intellectual disability in children may include the following:

  • Developmental milestones such as sitting, standing, crawling, walking, or talking are delayed.
  • Difficulty in understanding social rules such as waiting in line or taking turns.
  • Unable to understand dangerous situations, such as crossing a busy street. 
  • Lacking interest or curiosity about the things around them. 
  • Despite putting a lot of significant effort and repetition, they often have difficulty in learning new information.
  • Despite significant practice they have difficulty learning new skills
  • Ordinary and simple problems are often difficult to solve.
  • Difficulty in remembering things.
  • They find it difficult to meet educational demands. 
  • Behavioral problems such as impulsivity and low frustration tolerance.

When these signs are noticed in children, parents, caregivers, or teachers should discuss the matter with a healthcare provider. A formal assessment and evaluation of children may be needed. However, it can be difficult to assess intellectual disabilities in very young children who are 2 years old and below. For this reason, most clinicians are hesitant to diagnose intellectual disabilities in children younger than 2, except for known genetic disorders such as Down syndrome

It is important to speak with a doctor to understand more about your child’s mental and overall development. If you have a school-age child, you can also talk with your child’s teachers to know your child’s developmental progress and behavior in school.   

If the children's intellectual disability is severe, they may also have additional health issues such as vision or hearing problems, mental disorders, and seizures. Each level of intellectual disability is described according to the following categories:


  • The IQ level is 50-70
  • Slower in all areas 
  • Can socially conform
  • Daily task skills can be acquired
  • Socially integrated 
  • Absence of unusual physical signs 
  • Practical skills can be acquired
  • Able to read and have math skills up to 3rd to 6th grade


  • The IQ level is 35-49
  • Able to participate in simple activities and self-care
  • Supervised tasks can be performed
  • Able to travel alone to familiar places
  • Noticeable speech or language delay
  • Some physical signs may be observed
  • Simple communication may be learned
  • Elementary health and safety skills can be learned


  • The IQ level is 20-34
  • Significant delay in some areas 
  • Can be trained with simple self-care
  • Needs social direction and supervision 
  • Poor communication skills but there are some responses and understanding of speech 
  • Daily routines and repetitive activities can be taught


  • The IQ level is less than 20
  • Significant delays are seen in all areas 
  • May respond to regular physical and social activities 
  • Unable to take care of themselves
  • Abnormalities in cognition
  • Close supervision is needed
  • Attendant care is needed

Intellectual deficits, as well as adaptive functioning deficits, are seen in individuals with intellectual disabilities. Deficits are observed in conceptual, social, and practical domains.

Intellectual Function Deficits

  • Reasoning
  • Language development
  • Planning
  • Problem-solving
  • Abstract thinking
  • Judgement
  • Academic learning
  • Learning from experience

Adaptive Functioning Deficits

The child fails to meet the standards of development and sociocultural standards. The child is also unable to meet and understand its social responsibility. In one or more daily activities, the child may show limited functioning when it comes to independent living, social participation, communication at home, work, school, and community.

The severity level will determine the level of support needed for adaptive functioning. The following are the signs and symptoms of deficits in adaptive functioning:

Conceptual Domain

  • Language development is slow
  • Shows slow development in pre-academic skills 
  • Difficulties in academic learning, which includes mathematics, writing, and reading
  • Trouble understanding the concepts of money and time
  • Abstract thinking becomes difficult.
  • Trouble solving problems 
  • Executive functioning is difficult (difficulty in priority setting, strategizing, and planning cognitive flexibility)
  • Short-term memory problems

Social Domain

  • Limited language and communications skills 
  • Compared with peers the spoken language is less complex and more concrete
  • Vocabulary and grammatical skills is limited
  • Comprehension of simple speech and gestures is limited
  • Communication may occur through facial expressions, gestures, signs, and other forms of augmentative and alternative communication (AAC)

Social Skills

  • Social judgment and decision-making is immature
  • Trouble understanding social rules and peer social cues
  • Difficulties in emotional, social, and behavioral regulation

Practical Domain

  • For daily activities, different levels of support are needed, which includes personal care, employment, household tasks, recreational skills, health care, legal decisions, and other complex tasks.

Communication Patterns

Across the domains of phonology, morphology, semantics, pragmatics, and syntax, individuals may demonstrate signs and symptoms of spoken and written language disorders. These individuals belong to heterogeneous groups and their communication abilities may be nonsymbolic and may vary. It can also be symbolic in the form of signs such as pictures and words.

Intellectual Disabilities in Babies                                               

  • Genetic Disorders - Some degrees of mental disability are associated with certain genetic disorders such as Down syndrome. Usually, the facial or physical characteristics of children with genetic disorders alert doctors of potential problems. Children with Down syndrome have unusual and dysmorphic features, such as low-set ears, heavy eyebrows, or widely spaced eyes. This genetic disorder may cause intellectual disability. Other signs of the disorder are having a small head circumference along with hand and foot anomalies.
  • Physical Delays - Poor muscle tone, inability to coordinate, and poor sucking or swallowing are usually observed in infants with profound intellectual, cognitive, or developmental disabilities. Such children may be delayed in sitting or standing and may show delayed or slow development in other physical milestones. By 6 months, they may not roll over or crawl by 12 months. However, some of them are slow starters and eventually catch up with others.
  • Speech Delays - It is difficult to assess speech in babies, but the signs of delayed speech are observed as early as 3-6 months if they are unable to repeat sounds, or by 5-9 months if they are unable to babble. By 14 months, babies normally say their first word and before the age of two, they use two-word combinations.
  • Environmental Response - Normally, a newborn baby responds to voices and spontaneously smiles by 1-2 months of age. Intellectual impairment may be indicated if these milestones are not met. Other signs include not recognizing their parents at 3 months old, disinterest in other people, and lethargy.

The signs of intellectual disability may appear during infancy or when the child reaches school age. Intellectual disabilities in children have different signs. The common signs are as follows:

  • Delay in walking, sitting, crawling, or rolling over
  • May have trouble talking or may talk late
  • The child may take time to master certain things such as dressing, potty training, and feeding
  • Remembering things may become difficult
  • The child may find it difficult to connect actions to consequences
  • May display explosive tantrums
  • Problem with logical thinking or problem-solving
  • Other health problems such as mood disorders, seizures, impairment of skills, hearing problems, or vision problems.

About 1-3 percent of the population is affected by intellectual disabilities. The condition is mild in 85 percent of the population. It means that in learning new information or skills, they are just a little slower than average. Most of them are able to independently live as adults with the right support.

The child’s skills are observed to measure his or her adaptive behavior, and this observation is compared to children of the same age. Self-care, feeding, and dressing are observed. The ability of the child to understand and communicate with family and friends is also observed. Limitations in two areas are present in individuals with intellectual disability. They are:

  • Intellectual Functioning - This is also referred to as IQ. The ability of the person to reason out, learn, make decisions and solve problems are affected.
  • Adaptive Behavior - This includes skills that are required for daily living such as the ability to effectively communicate, self-care, and the ability to interact with others.

An individual's IQ is measured through IQ tests. Majority of people score between 85 and 115 since the average IQ is 100. If a person has an IQ of less than 70, then he or she is considered have an intellectual disability.