Mental retardation, which is now renamed as intellectual disability, is a type of neuro-developmental disorder, wherein the affected individuals have poor adaptive functioning along with impaired intellectual development. Individuals with an IQ score below 70 and a significant deficit observed in adaptive behaviors that interferes with general living are considered to be mentally retarded.
Presentation
Delay in development of language skills, adaptive skills and cognitive skills mark the onset of intellectual disability. In mild cases, signs and symptoms may not be noticeable until the child reaches preschool age. The following are some of the important markers noticed in affected children:
- Inability to speak mama/dada in the first year
- Child does not say 2 word phrases by the age of 2 years
- Delay in motor adaptive skills such as child does not dress up or practices such as self-feeding and or toileting are absent
- Delay in cognitive development, marked by inability of the child to follow instructions and lack of problem solving skills
- Behavioral disturbances are noticeable such as hyperactivity, disturbance in sleep and colic
Entire Body System
- Cerebral Palsy
[…] for Cerebral Palsy and Developmental Medicine (AACPDM). schema:workExample http://dx.doi.org/10.1111/(ISSN)1469-8749 > ; umbel:isLike http://d-nb.info/020059965 > ; wdrs:describedby http://www.worldcat.org/title/-/oclc/637828095 > ;. [worldcat.org]
palsy (n = 100, 2.0%). [ncbi.nlm.nih.gov]
Assessment checklist for various disabilities namely cerebral palsy, hearing impairement, mental retardation, visually impairement and learning disability are available for identifying special needs of children studying in an inclusive education setup [play.google.com]
Features Associated With MR Feature Mild MR Moderate-severe MR Seizures 12% 35% Cerebral Palsy 9% 20% Blindness 1% 15% Deafness 7% 10% Table 2. [thedoctorwillseeyounow.com]
palsy ( n = 100, 2.0%). [doi.org]
- Trisomy 21
In Trisomy 21, the affected child inherits three chomosome 21's. [thedoctorwillseeyounow.com]
For example, if a baby is born with three #21 chromosomes, rather than the usual pair, the baby would be said to have "trisomy 21". Trisomy 21 is also known as Down syndrome. Other examples of trisomy include trisomy 18 and trisomy 13. [chw.org]
The characteristic phenotype of Down syndrome is basically the same in trisomy 21 and in translocation. [emedicine.com]
- Weight Gain
A longitudinal clinical course beginning in childhood revealed excessive weight gain, poor language skills and poor school performance. Chronic kidney disease stage 4, with elevated blood pressure, was first noted in adulthood. [ncbi.nlm.nih.gov]
Gain and Brain Development in Malnourished Children May 1, 2018 — High dose vitamin D supplements improve weight gain and the development of language and motor skills in malnourished children, according to a new ... read more Neuroscience Study Identifies [sciencedaily.com]
Vomiting Hypoglycemia Seizure Lethargy, irritability Poor weight gain Hepatic failure Splenomegaly Mental retardation Ascitis 22. [slideshare.net]
Assessment of maternal health status during pregnancy with the involved child should include questions regarding use of tobacco, alcohol and drugs (prescribed and illicit); lifestyle or other risks for sexually transmitted diseases; weight gain or loss [web.archive.org]
- Fever
The common symptoms and signs of eosinophilic meningitis are severe headache, neck stiffness, paresthesia, vomiting, nausea, and fever. Acute urinary retention is a rare presentation. [ncbi.nlm.nih.gov]
History of first-trimester infection/fever (%) ( n = 1,041) 0.4 0.7 0.5 20. Pregnancy-related hypertension (%) ( n = 1,041) 8.3 9.8 9.6 21. Small for gestation (%) ( n = 8,387) 5.4 12.0 8.6 Perinatal factors 22. [academic.oup.com]
Prenatal causes of mental retardation include congenital infections such as cytomegalovirus, toxoplasmosis, herpes, syphilis, rubella and human immunodeficiency virus; prolonged maternal fever in the first trimester; exposure to anticonvulsants or alcohol [web.archive.org]
- Progressive Intellectual Disability
The patient was an 11-year-old girl with onset of seizures at the age of 18 months and followed by progressive intellectual disability (ID) later. [ncbi.nlm.nih.gov]
Milder cases of progressive intellectual disability can sometimes be traced to economic and environmental deprivation early in childhood—conditions that are associated with poverty or famine. [britannica.com]
Gastrointestinal
- Failure to Thrive
The patient presented with exocrine pancreatic insufficiency as well as failure-to-thrive. On dysmorphological examination, she was noted to have an abnormal hair pattern with frontal upsweep and alae nasi hypoplasia. [ncbi.nlm.nih.gov]
Clinical manifestations (eg, failure to thrive, lethargy, vomiting, seizures, hypotonia, hepatosplenomegaly, coarse facial features, abnormal urinary odor, macroglossia) may suggest a genetic metabolic disorder. [msdmanuals.com]
Translated by Apolline Morville B.2 Failure to thrive or weight faltering in a primary health care setting (824 KB PDF) Astrid Berg VERSION IN FRENCH: “ Retard de croissance ou prise de poids hésitante en contexte de soin de santé primaire ” (1.27 MB [web.archive.org]
Jaw & Teeth
- Dental Caries
Special care in dentistry, 20(4): 131-8 [ PM ] [ EČ ][ 1 ][ GS ] Ivancić, J.N., Majstorović, M., Bakarcić, D., Katalinić, A., Szirovicza, L. (2007) Dental caries in disabled children. [scindeks.ceon.rs]
There is evidence of increased risk of obesity, fractures, poor oral health (including dental caries and loss of teeth), constipation and gastro-oesophageal reflux disease. [ 1 ] Psychological (the following are more common in patients with learning disabilities [web.archive.org]
Poor oral health (including dental caries and loss of teeth). Poor diet, increased rates of constipation and gastro-oesophageal reflux disease. Lack of physical exercise. Sleep disorders. Increased risk of chronic obstructive pulmonary disease. [patient.info]
- Periodontitis
The aim of this cross-sectional study was to determine the oral health and periodontal status of MR patients in Turkey with regard to periodontal indices and Decay missed filling teeth (DMFT) scores and compare findings according to severity of the MR [ncbi.nlm.nih.gov]
Collegium antropologicum, 31(1): 321-4 [ GS ] Jayakumar, H.L., Jyoth, D., Chandra, M.K., Pallavi, H. (2011) Periodontal health among elderly psychiatric patients in Bangalore city - India. [scindeks.ceon.rs]
Shirke and Prashant Jadhav, Oral Hygiene Status, Periodontal Status, and Periodontal Treatment Needs among Institutionalized Intellectually Disabled Subjects in Kolhapur District, Maharashtra, India, Journal of Oral Diseases, 2014, (1), (2014). [doi.org]
- Toothache
Direct support and coaching of young people with learning disability are efficient ways to improve their integration into employment. [ 6 ] If a person presents with challenging behaviour, assess for physical (for example, pain such as toothache, earache [web.archive.org]
If a person presents with challenging behaviour, assess for physical (for example, pain such as toothache, earache) and other sources of discomfort before treating the behaviour as psychiatric [ 1 ]. [patient.info]
- Poor Oral Hygiene
CONCLUSION: The deteriorated teeth condition and deprived periodontal health of MR patients may be most likely caused by the poor oral hygiene and may be worsen with the severity of the MR. [ncbi.nlm.nih.gov]
Psychiatrical
- Impulsivity
Abstract Hyperactivity syndromes and disorders (ADHD and HKD) include the symptoms of overactivity, inattention, and impulsivity, which occur in many other mental disorders as well, including mental retardation (MR). [ncbi.nlm.nih.gov]
[…] interacting with others If your child has ID, they will probably experience some of the following behavioral issues: aggression dependency withdrawal from social activities attention-seeking behavior depression during adolescent and teen years lack of impulse [helpingchildclinic.com]
[…] pictures Attention Deficit Hyperactivity Disorder- : Attention Deficit Hyperactivity Disorder- dysfunction of central nervous system leading to problems in attention not focus on one task display behavioural problem along with poor academic performance impulsivity [authorstream.com]
There is social withdrawal in both the disorders but in autism there is inability of communication due to delayed impulse transmission whereas in mental retardation there is loss of cerebral functioning responsible for all poor development of all skills [differencebetween.net]
Turkish] Mehmet Emrah Karadere, Ece Yazla, Hüseyin Şehit Burhan, Ebru Turgal, Tacettin Kuru, Mehmet Hakan Türkçapar Anadolu Psikiyatri Derg. 2020; 21(3): 269-276 » Abstract » PDF» doi: 10.5455/apd.82968 The relationship between metabolic syndrome and impulsivity [anadolupsikiyatri.net]
- Impulsivity
Abstract Hyperactivity syndromes and disorders (ADHD and HKD) include the symptoms of overactivity, inattention, and impulsivity, which occur in many other mental disorders as well, including mental retardation (MR). [ncbi.nlm.nih.gov]
[…] interacting with others If your child has ID, they will probably experience some of the following behavioral issues: aggression dependency withdrawal from social activities attention-seeking behavior depression during adolescent and teen years lack of impulse [helpingchildclinic.com]
[…] pictures Attention Deficit Hyperactivity Disorder- : Attention Deficit Hyperactivity Disorder- dysfunction of central nervous system leading to problems in attention not focus on one task display behavioural problem along with poor academic performance impulsivity [authorstream.com]
There is social withdrawal in both the disorders but in autism there is inability of communication due to delayed impulse transmission whereas in mental retardation there is loss of cerebral functioning responsible for all poor development of all skills [differencebetween.net]
Turkish] Mehmet Emrah Karadere, Ece Yazla, Hüseyin Şehit Burhan, Ebru Turgal, Tacettin Kuru, Mehmet Hakan Türkçapar Anadolu Psikiyatri Derg. 2020; 21(3): 269-276 » Abstract » PDF» doi: 10.5455/apd.82968 The relationship between metabolic syndrome and impulsivity [anadolupsikiyatri.net]
- Withdrawn
The effects of reinforcement on the spontaneous social initiations of socially withdrawn preschoolers. Journal of Applied Behavior Analysis, 31, 117 - 125. Google Scholar | Crossref | Medline | ISI Zanolli, K., Daggett, J., & Adams, T. ( 1996 ). [doi.org]
24.4 33.5 31.2 23.6 Cries for long period for no apparent reason 14.6 11.6 9.8 16.0 10.5 15.2 12.5 MOODS (excludes persons with profound mental retardation) Frequently worried/ apprehensive 28.0 35.9 30.1 33.3 32.8 13.0 31.4 Frequently unresponsive/ withdrawn [aspe.hhs.gov]
- Inappropriate Sexual Behavior
Some common behaviors associated with Alzheimer’s disease are rapid mood changes, crying, anger, pacing, wandering, doing things over and over, asking the same question, following people closely and inappropriate sexual behaviors. [services.dpw.state.pa.us]
Urogenital
- Amenorrhea
Our case provides evidence for an association of primary amenorrhea and mental retardation with concomitant unbalanced X-autosome translocation and X chromosome rearrangement. [ncbi.nlm.nih.gov]
Neurologic
- Tantrums
Your child may have: Language problems, such as a later start using words or speaking in full sentences Trouble making friends and other social skills Trouble dressing and doing other self-care tasks Sometimes, behavior problems such as temper tantrums [msdmanuals.com]
[…] sitting up and walking Late start in talking or difficulty in talking Late in getting potty trained, doing activities like dressing or feeding independently Difficulty in remembering things or associating actions with corresponding consequences Throwing tantrums [newhealthguide.org]
[…] walking late Talking late or having trouble with talking Slow to master things like potty training, dressing, and feeding himself or herself Difficulty remembering things Inability to connect actions with consequences Behavior problems such as explosive tantrums [webmd.com]
- Stroke
Personer med psykisk funktionsnedsättning har i högre utsträckning fetma och har högre mortalitet som relateras till de metabola effekter t.ex. hjärtinfarkt, stroke samt följd sjukdomar av diabetes. [esh.diva-portal.org]
Acquired neurologic deficits associated with postnatal insults such as central nervous system infections, hypoxic injury, trauma, and stroke are excluded. [epilepsy.com]
Serious head injury, stroke, or certain infections such as meningitis can cause mental retardation in older children. Intelligence refers to a general mental capability. [definitions.uslegal.com]
Turner and Moss (1996) discuss how alcohol consumption has been linked to hypertension, CVD and stroke in people with LDs. [web.archive.org]
- Irritability
The cornea is the clear (transparent) outer layer of the eye, and has two functions – it protects the rest of the eye from dust, germs and other harmful or irritating material, and it acts as the eye’s outermost lens, bending incoming light onto the inner [rarediseases.org]
Fecal transplant is used to treat gut infections and is now being studied as a treatment for obesity, urinary tract infections, irritable bowel syndrome and more. [nytimes.com]
But I'm glad to see that non-disabled people are beginning to understand why less offensive words such as 'special', 'brave' and 'wheelchair-bound' are so irritating to many disabled people. [web.archive.org]
Vomiting Hypoglycemia Seizure Lethargy, irritability Poor weight gain Hepatic failure Splenomegaly Mental retardation Ascitis 22. [slideshare.net]
Buspirone in the management of anxiety and irritability in children with pervasive developmental disorders: results of an open-label study. J Clin Psychiatry. 1998 ; 59 : 56 – 59 ↵ Kowatch RA, DelBello MD. [doi.org]
- Delayed Milestone
In mental retardation, the child tends to have delayed milestones and will be slow in talking and walking. The low IQ restricts the memory and children have lower than average learning abilities and problem solving skills. [differencebetween.net]
[…] to hypoplastic facial features, developmental delay, small stature and familial resemblance. [aafp.org]
- Tic Disorder
Lasfar H.2 Tic disorders (438 KB PDF) Hannah Metzger, Sina Wanderer & Veit Roessner VERSION IN FRENCH “ Les tics ” (1 MB PDF) Editor: Priscille Gerardin. Translated by V. [web.archive.org]
Obsessive-compulsive disorder, conduct disorder, tic disorders, and other stereotypic behaviors are also diagnosed more commonly in those with MR/ID. [emedicine.com]
Workup
Based on the guidelines provide by the Diagnostic and Statistical Manual of Mental Disorders, the child should meet the following three criteria to be diagnosed with intellectual disability.
- Limitations in adaptive behavior such as interpersonal skills, communication and self-help skills
- Deficits in mental abilities
- Signs and symptoms become evident early in life
The first 2 factors can be diagnosed by measuring the IQ score. The third factor is important to determine, in order to rule out other disorders like Alzheimer disease which share similar signs and symptoms, but have a late onset.
An IQ score of below 70 indicate mental retardation and is done at the preliminary level. This is followed by other methods such as adaptive behavior rating scale and Denver developmental screening test [8].
Brain imaging tests are also indicated in children with intellectual disability. A MRI scan of brain is preferred, because it enables better assessment of abnormalities of central nervous system [9].
Treatment
Treatment is geared towards maximum development of the child’s potential. Therapists and specialized educators help in fulfilling such goals. They help in developing the social skills of the child so that they learn to communicate effectively and put forth their problems and thoughts to the outside world. Behavior counseling forms an important part of the treatment regime to help the child to deal with their mood swings and sometimes aggressive nature.
Pharmacologic treatment is of little help in improving the cognitive functioning. However, the drug donezepil has been found to be effective in improving the cognitive function in children with Down syndrome. Parents might also think of enrolling their children in various support groups for proper grooming [10].
Prognosis
Prognosis of the condition would largely depend on the underlying etiology, severity of the disease and type of treatment methods administered. In many cases it has been seen that, affected individuals lead a productive life and learn to carry out many tasks on their own. With proper learning and education, children can function properly and can be successful in life [7].
Etiology
Amongst the various etiologies, Down syndrome, fetal alcohol syndrome and velocariofacial syndrome are the major causative factors [2]. In about one third to the half of all cases, the exact cause behind development of mental retardation is not known [3].
The following causes are known to trigger the onset of mental retardation:
- Infections that occur during birth or after it
- Chromosomal abnormalities
- Malnutrition during pregnancy
- Alcohol consumption during pregnancy can cause improper fetal development
- Exposure to disease conditions such as measles, pertussis and meningitis
- Iodine deficiency
- Absence of arcuate fasciculus
Epidemiology
Mental retardation affects about 1 – 3% of the total population. The prevalence rate of severe form of intellectual disability has been estimated to occur in 6 per 1,000 population [4].
It has been assessed that, about 75 – 90% of individuals suffer from mild form intellectual disability. Of these, non-syndromic intellectual disability occurs in about 30 – 50% of cases. Boys are found to be more affected than girls, for both mild and severe form of the disease. Mortality rates at an early age have been found to be higher in children suffering from Down syndrome [5].
Pathophysiology
Mental retardation primarily occurs as the outcome of several disorders of the central nervous system. In majority of the cases, no significant structural abnormalities have been noticed in individuals with mild intellectual disability. However, in severe cases, malformations of the central nervous system include hydranencephaly, neural tube defects and microcephaly. Certain studies have indicated a link between poor cognitive functioning and poverty; however the etiologic contribution still remains unclear [6].
Prevention
Some of the risk factors such as alcohol consumption during pregnancy, avoiding toxin exposure and iodine deficiency can go a long way in preventing the onset of mental retardation. Getting vaccinated against infectious diseases such as rubella can also help prevent mental retardation from setting in. Proper genetic counseling during pregnancy can help parents take informed decisions.
Summary
The condition is diagnosed before one reaches 18 years. Individuals suffering from mental retardation lack in appropriate mental development and do not have the ability to adapt and learn new things. Intellectual disability is further classified into 2 categories: non-syndromic intellectual disability and syndromic intellectual disability [1].
Patient Information
- Definition: Mental retardation, also known as intellectual disability, is a type of neuro-developmental disorder, wherein there is impairment of adaptive functioning and intellectual skills. Affected individuals have an IQ score of 70 or below.
- Cause: Various disease conditions such as Down syndrome, fetal alcohol syndrome and velocariofacial syndrome predisposes children to develop intellectual disability. In addition, various other risk factors include alcohol consumption during pregnancy, exposure to toxins, infectious diseases, iodine deficiency, chromosomal abnormalities and malnutrition.
- Symptoms: Signs and symptoms of intellectual disability include delay in development of cognitive skills, motor skills, language delays, continuation of infant type behavior till late years, difficulty in following instructions and aggressive behavior.
- Diagnosis: Diagnosis includes assessing the IQ score and testing the adaptive behavior of the individual with help of adaptive behavior rating scale. In addition, imaging studies like CT scan and MRI of brain is also required to assess abnormalities.
- Treatment: Treatment is geared towards developing the potential of the children as much as possible. This is done by therapists and specialized educators who provide training and behavior counseling to help develop their skills. Some medications such as donezepil have been found to be effective for patients with Down syndrome; it helps improve their cognitive functioning.
References
- Biscaldi M, Rauh R, Irion L, Jung NH, Mall V, Fleischhaker C, et al. Deficits in motor abilities and developmental fractionation of imitation performance in high-functioning autism spectrum disorders. Eur Child Adolesc Psychiatry. Oct 2 2013
- American Academy of Pediatrics Committee on Genetics. Health Supervision for Children with Down Syndrome. Pediatrics. February 2001,;volume 107, number 2,:pages 442-449
- Croen LA, Grether JK, Selvin S. The epidemiology of mental retardation of unknown cause. Pediatrics 2001; 107:E86.
- American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders.5th Edition. Washington, DC: APA Press; 2013.
- Kaufman L, Ayub M, Vincent JB. The genetic basis of non-syndromic intellectual disability: a review. J NeurodevDisord 2010; 2:182.
- Ramer JC, Miller G. Overview of Mental Retardation. In: Static Encephalopathies of Infancy and Childhood, Miller G, Ramer JC (Eds), Raven Press, New York 1992.
- vanKarnebeek CD, Scheper FY, Abeling NG, et al. Etiology of mental retardation in children referred to a tertiary care center: a prospective study. Am J Ment Retard 2005; 110:253.
- Majnemer A, Shevell MI. Diagnostic yield of the neurologic assessment of the developmentally delayed child. J Pediatr 1995; 127:193.
- Bouhadiba Z, Dacher J, Monroc M, et al. [MRI of the brain in the evaluation of children with developmental delay]. J Radiol 2000; 81:870.
- McConkey R, Kelly F, Mannan H, Craig S. Moving from family care to residential and supported accommodation: national, longitudinal study of people with intellectual disabilities. Am J Intellect Dev Disabil 2011; 116:305.