Logo site
Logo site

Mental Retardation in Infants: Causes, Forms and Management

Mental Retardation in Infants: Causes, Forms and Management

Mental retardation in infants is a critical test for all family members. Parents often search for the causes of their unhappiness, pestering doctors with a volley of questions regarding who should be blamed for the development being affected. Parents often support their own interpretation of what happened and wait for confirmation from a doctor. For example, the father blames his wife, who suffered a cold during pregnancy, dressing elegantly but insufficiently to protect herself from the cold. At the same time, the mother blames her husband for his chronic drinking and inherited factors such as epilepsy in the family. Finally, parents often blame gynecologists and doctors who allegedly overlooked or neglected something.

Somehow, it has happened. As a rule, there is no definitive answer to the question “Which is to blame” and this issue will remain silent until the quest arises regarding the possibility of the next child. In such a case, both parents must undergo tests and genetic counseling. Under these conditions, undoubtedly, the search for the culprit is destructive. These conditions further reflect a sense of guilt and their attempt to subdue those experiences that can further lead to the deterioration of family relationships. When a problem of a mentally disabled infant occurs in a family, all family members need to support each other as the moral support of each family member plays a powerful role in overcoming depressive moments.

It becomes the responsibility of the parents to accept the child, create favorable conditions for his or her development, and at the same time, not overlook his capabilities and demands. Otherwise, it may create a cult of complexes based on parents’ belief that the child may not be lucky to them. These conditions further affect the psychology of the infant, leading to his being self-centered, poorly adapted and under-trained. With the right approach, the infant starts enjoying life and developing the ability to enjoy communication with the parents, even though the success may be moderate. A mentally disabled infant always be under the supervision of a psychiatrist who knows a family’s medical history, and parents should not rush from one psychiatrist to another in search of a miraculous healer. Competent psychiatrists constantly observe the child’s needs. Their periodical checkups improve the child’s development, thus preventing a child from further related neurotic reactions. Hence, a mental disability can blanket the family shame of the chronic traumatic factor so that the kid can bring joy to his/her parents just as other healthy children. It all depends upon the parents’ attitude towards him/her, and a proper attitude toward the tasks of treatment and education is the correct approach.

The Concept of Mental Retardation

According to local experts, mental retardation consistently violates certain mental quality structures in an infant’s nervous system. Mental retardation leads to the failure of cognitive activity and causes persistent underdevelopment of abstract processes of generalization combined with the inertia of mental processes. Based primarily on data from psychometric research, the literature defines several approaches to the definition of infant mental retardation.

The Main Forms of Mental Retardation


When mental retardation occurs early in Uterus, brain underdevelopment occurs. It is caused by hereditary influences or a variety of damaging environmental factors. This fatal development occurs at birth and during the first year of an infant’s life. When there is an increase in mental retardation, the intellectual defect occurs. The behavior of mental disorders associates with the age patterns of the child’s development. Oligophrenia is a total underdevelopment characteristic of neuropsychological functions with primary failures of abstract thought forms.

Intellectual defect combines with impaired motor skills, speech, perception, memory, attention, emotional development, and arbitrary behavior. Hypoplasia of cognitive activity in oligophrenia demonstrates the primary failure of logical thinking, mobility impairments of mental processes, and the inertia of thinking. In such cases, the weakness of logical thinking is rooted in the low level of generalization, comparison of objects and phenomena of reality, and inability to understand the symbolic meaning of proverbs and metaphors.

Further, thinking slows down, and the typical inertia of mental processes does not transfer a learning mode of action to the new conditions. In mentally disabled infants, underdevelopment of thinking affects the flow of mental processes. In perception, memory primarily affects the functions of abstraction and generalization, i.e., always broken components of mental activity affect the analytic-synthetic activity of the brain. Hence, the emotional volitional sphere reflects low complex emotions and arbitrary behavior.

When the intellectual defect persists, severe forms can be noticed in the first months of an infant’s life. In oligophrenia, there are three degrees of mental retardation: debility, silliness, and idiocy. Debility is the lightest degree and the most common form of mental retardation (IQ 50-69). The social outlook is favorable in the absence of complicating intellectual impairment disorders and early and appropriate corrective measures. More severe mental retardation is imbecility (IQ 20-49), when imbecility grossly violates the ability to abstract and form concepts. The most severe mental retardation is idiocy (IQ under 20), characterized by gross underdevelopment of all mental functions.


Dementia is a decay process more or less formed in the intellectual and other mental functions, i.e., dementia occurs because of the acquired intellectual defect.

At an early age, distinguishing between dementia and mental retardation is challenging. The fact is that any disease or damage to the brain results in the loss of previously acquired skills, and decay generated by intellectual functions endnotes delay in mental development in general. Therefore, it is extremely difficult to distinguish between acquired and innate intellectual failure at an early age. In connection with acquiring the intellectual defect associated with progressive organic brain disease, epilepsy and schizophrenia beginning in the first years of life need to be considered. This process has a complex structure. It includes both individual features of dementia and mental retardation. In the event of dementia in children within three years, the delimitation of mental retardation becomes clearer. For differentiation of these forms of intellectual disturbances, it is essential to bear in mind that in dementia, mental retardation occurs during normal intellectual development. Furthermore, the structure of mental disorders in dementia has characteristics that illustrate the uneven cognitive failure of various functions. Dementia may be a discrepancy between the amount of knowledge and the limited capacity to implement it.

The disturbances of mental capacity, memory, attention, behavior regulation, and motivation mark typical signs of dementia at an early age, and dementia manifests as a late loss of acquired skills. For example, if dementia occurs in a child aged three, it causes him to miss the initial skills of self and neatness. The child may then lose previously acquired skills, such as walking and a sense of attachment to the nearest ones.

Rett Syndrome

One form of the disease similar to oligophrenia that includes features of dementia and mental retardation is Rett syndrome. The Austrian psychiatrist A. Rhett first described this disease about 20 years ago. It occurs only in girls with a frequency of 1:12500. Symptoms of the Rett syndrome development become apparent at 12-18 months when the girl begins to lose barely formed speech, locomotors-static and object manipulative skills.

The characteristic feature of this disease is a combination of loss of purposeful hand skills and stereotypical (uniform) actions of the hands in the form of rubbing and wringing. The monotonous rubbing of hands in some children has peculiar movements of arms in front of the chest or chin. At an early age, the identified movement shows difficulty in walking.

When Rett syndrome symptoms manifest themselves, one may see pale skin, constantly cold hands and feet, general bodily weakness, sharply decreased appetite, and difficulty chewing and swallowing. Girls hold food in their mouths for a long time without swallowing it. Many patients must be fed because they do not know how to use a spoon or a fork.

Further, the Rett syndrome shows characteristics of the violation of posture and the gradual development of scoliosis. The posture and movement of infant girls become extremely monotonous and motor awkward. They find it difficult to manipulate objects and do not play with dolls and other toys. Neurologists usually say that they have the overall muscle tone reduced.

Difficulties in mastering walking and simplest object actions, lack of coordination of movements, and low muscle tone are typical features of Rett disease and cerebral palsy. Hence, sometimes children ill for a long time can be misdiagnosed as having cerebral palsy.

The characteristic feature of the Rett syndrome is a persistent lack of imitative activity and delays in the development of material and practical activities and speech communication. The sick kids have hardly expressive faces; they look “lifeless” or “unhappy”. One often encounters a look of a still, focusing on an object for a long time.

Although several factors, such as degree and cause of severity, change from person to person, some general predisposing factors are connected with infant mental retardation. The first factors of this type are hereditary; for example, an infant may be suffering from inborn errors of metabolism (these occur when the infant’s body cannot transform food into energy, such as in the case of Phenylketonuria disorder), single genetic abnormalities, and several chromosomal aberrations.

Another reason for infant mental retardation is the mother’s exposure to teratogens or external factors that the mother can encounter during pregnancy, which damages the progressing baby in the womb. Teratogens can contain toxins in women who use drugs or medications during pregnancy or are exposed to diseases or infections. Several other factors during the stage of pregnancy that can influence a child to develop mental retardation are fetal malnutrition, hypoxia, prematurity, or trauma. Environmental effects may also play a crucial role: for example, infants brought up in impoverished environments may develop mental retardation. Besides, other mental disorders can cause infants to have mental retardation, such as Autism Spectrum Disorder or other Pervasive Developmental Disorders. Finally, overall medical conditions obtained in infancy may also cause mental retardation. These include infections such as measles or meningitis. If not treated properly, these may cause retardation or exposure to certain toxins such as lead or mercury.

Prenatal Problems

Mental disability in infants can occur when the fetus does not develop inside the mother’s womb. Moreover, prenatal reasons comprise congenital infections such as toxoplasmosis, cytomegalovirus, herpes, rubella, syphilis, and human immunodeficiency virus. Complications of prematurity in low-weight infants can also lead to mental retardation.


Mental retardation in infants is a genetic disorder that usually manifests in below-average intellectual functioning and deficiency in adaptive behavior. Several genetic or multiple factors can create mental retardation in infants. Doctors cannot determine the etiology in at least 25 to 40% of cases despite thorough assessment. The systematic review of infants should be conducted with individual attention to growth problems, lethargy, history of seizures, and episodic vomiting.

📎 References:

1. American Association on Intellectual and Developmental Disabilities. (2002). Mental Retardation: Definition, classification and systems of supports (10th ed.). Washington, D.C.: AAIDD.
2. Badano, J.L., Mitsuma, N., Beales, P.L., Katsanis, N. (2006). The ciliopathies: An emerging class of human genetic disorders. Annual Review of Genomics and Human Genetics, 7, 126-140.
3. Baird, P. A., & Sadovnick, A. D. (1985). Mental retardation in over half-a-million conservative livebirths: An epidemiological study. American Journal of Mental Deficiency, 89, 324-329.
4. Baroff, G.S. (1991). Developmental disabilities: Psychological aspects. Austin, TX: Pro-Ed.
5. Daily, D.K., Ardinger, H.H., & Holmes, G.E. (2000). Identification and evaluation of mental retardation. American Family Physician, 61(4), 1059-1067.
6. Kolevzon, A., Gross, R., & Reichenberg, A. (2007). Prenatal and Perinatal Risk Factors for Autism: A Review and Integration of Findings. Arch Pediatr Adolesc Med, 161(4), 327-331.
7. Matson, J.L., & Sevin, J.A. (1994). Theories of dual diagnosis in mental retardation. Journal of Consulting and Clinical Psychology, 62(1), 7-14.
8. Palmer, F.B., & Capute, A. J. (1994). Mental retardation. Pediatric Review, 15, 476-478.
9. Piecuch, R.E., Leonard, C.H., Cooper, B.A., Sehring, S.A. (1997). Outcome of extremely low birth weight infants (500 to 999 grams) over a 12-year period. Pediatrics, 100, 34-67.