This document discusses mental retardation, including definitions, classifications, degrees of severity, common genetic causes like Down syndrome and fragile X syndrome, epidemiology, comorbid conditions, etiology, and specific genetic syndromes associated with intellectual disabilities like phenylketonuria. It provides information on prominent advocacy organizations, how mental retardation is diagnosed and coded in diagnostic manuals, and adaptive and intellectual functioning assessments.

1. Mental Retardation

2. Intellectual Functioning & Adaptive
Functioning
• The conceptualization of mental retardation
includes deficits in cognitive abilities as well as
in behaviors required for social and personal
sufficiency, known as adaptive functioning.
• Measures of adaptive function assess
competency in performance of everyday tasks,
whereas measures of intellectual function
focus on cognitive abilities.

3. Organizations
• The most prominent advocacy organization in this
field is the American Association on Mental
Retardation (AAMR), which has been most
influential in educating the public about mental
retardation and in supporting research and
legislation relating to mental retardation.
• The AAMR promotes designating an IQ of 75,
rather than 70, as the beginning level of the mild
mental retardation range, thereby enabling many
more persons to receive services as mentally
retarded.

4. Nomenclature
• According to DSM-IV-TR, a diagnosis of mental
retardation can be made only when both the
IQ, as measured by a standardized test, is
subaverage and a measure of adaptive
function reveals deficits in at least two of the
areas of adaptive function.
• Mental retardation diagnoses are coded on
Axis II in the DSM-IV-TR.

5. Classification
• According to the DSM-IV-TR, mental retardation
is defined as significantly subaverage general
intellectual functioning resulting in, or associated
with, concurrent impairment in adaptive behavior
and manifested during the developmental period,
before the age of 18.
• The diagnosis is made regardless of whether the
person has a coexisting physical disorder or other
mental disorder.

6. Degrees of Mental
Retardation
1) Mild
2) Moderate
3) Severe
4) Profound
 Term significantly subaverage is defined as an
IQ of approximately 70.
 Adaptive functioning can be measured by
using a standardized scale, such as the
Vineland Adaptive Behavior Scale.

7. Degrees of Severity of Mental
Retardation
• Borderline intellectual functioning,
according to DSM-IV-TR, is not within the
diagnostic boundary of mental retardation and
refers to a full-scale IQ in the 71 to 84 range that
is a focus of psychiatric attention.
• Mild mental retardation (IQ range, 50 to 70)
represents approximately 85 percent of persons
with mental retardation.
• Many adults with mild mental retardation can live
independently with appropriate support and
raise their own families. 

8. Moderate Mental Retardation
• Moderate mental retardation (IQ range, 35-50)
represents about 10 percent of persons with
mental retardation.
• They are challenged academically and often are
not able to achieve academically above a second
to third grade level.
• As adults, persons with moderate mental
retardation may be able to perform semiskilled
work under appropriate supervision.

9. • Severe mental retardation (IQ range, 20-35)
comprises about 4 percent of individuals with
mental retardation.
• In adulthood, persons with severe mental
retardation may adapt well to supervised
living situations, such as group homes, and
may be able to perform work-related tasks
under supervision.

10. Profound Mental Retardation
• Profound mental retardation (IQ range below 20)
constitutes approximately 1 to 2 percent of
persons with mental retardation.
• Most individuals with profound mental
retardation have identifiable causes for their
condition.
• Children with profound mental retardation may
be taught some self-care skills and learn to
communicate their needs given the appropriate
training.

11. Mental Retardation, Severity
Unspecified
• The DSM-IV-TR lists mental retardation, severity
unspecified, as a type reserved for persons who are
strongly suspected of having mental retardation, but
who cannot be tested by standard intelligence tests or
are too impaired or uncooperative to be tested.
• This type may be applicable to infants whose
significantly subaverage intellectual functioning is
clinically judged but for whom the available tests (e.g.,
Bayley Scales of Infant Development and Cattell Infant
Scale) do not yield numerical IQ values.
• This type should not be used when the intellectual
level is presumed to be above 70.

12. Epidemiology
• Prevalence- 1% to 3%.
• Highest incidence- school-age children with
the peak at the ages 10 to 14 years.
• 1.5 times more common among men than
among women.

13. COMORBIDITY
Prevalence
• A recent epidemiological study found that 40.7 percent
of intellectually disabled children between 4 and 18
years of age met criteria for at least one psychiatric
disorder.
• The severity of retardation affected the type of
psychiatric disorder.
• The mental disorders that occur among persons who
are mentally retarded appear to run the gamut of
those seen in persons not mentally retarded, including
mood disorders, schizophrenia, attention-
deficit/hyperactivity disorder (ADHD), and conduct
disorder.

14. Neurological Disorders
• In a recent review of psychiatric disorders in
children and adolescents with mental
retardation and epilepsy, approximately one
third also had autistic disorder or an autistic-
like condition.
• The combination of mental retardation, active
epilepsy, and autism or an autistic-like
condition occurs at a rate of 0.07 percent in
the general population.

15. Psychosocial Features
• A negative self-image and poor self-esteem
are common features of mildly and
moderately mentally retarded persons, who
are well aware of being different from others.
• The perpetual sense of isolation and
inadequacy has been linked to feelings of
anxiety, anger, dysphoria, and depression.

16. Etiology
• Overall, in up to two thirds of all mentally retarded persons,
the probable cause can be identified.
• Among chromosomal and metabolic disorders, Down
syndrome, fragile X syndrome, and phenylketonuria (PKU)
are the most common disorders that usually produce at
least moderate mental retardation. Those with mild mental
retardation sometimes have a familial pattern apparent in
parents and siblings.
• Deprivation of nutrition, nurturance, and social stimulation
can contribute to the development of mental retardation.
Current knowledge suggests that genetic, environmental,
biological, and psychosocial factors work additively in
mental retardation.

17. Genetic Etiological Factors in Mental
Retardation
• Abnormalities in autosomal chromosomes-
mental retardation.
• Aberrations in sex chromosomes- physical
syndromes that do not include mental
retardation (e.g., Turner's syndrome with XO and
Klinefelter's syndrome with XXY, XXXY, and XXYY
variations).
• Agreement exists on a few predisposing factors
for chromosomal disorders- among them,
advanced maternal age, increased age of the
father, and X-ray radiation.

18. Down Syndrome (trisomy 21
syndrome)
• Down syndrome has been the most investigated,
and most discussed, syndrome in mental
retardation.
• Children with this syndrome were originally called
mongoloid because of their physical
characteristics of slanted eyes, epicanthal folds,
and flat nose.
• Despite a plethora of theories and hypotheses
advanced in the past 100 years, the cause of
Down syndrome is still unknown.

19. A. A young child with Down syndrome. B. A
young adult with fragile X syndrome.

20. Fragile X Syndrome
• Fragile X syndrome is the second most common
single cause of mental retardation.
• The syndrome results from a mutation on the X
chromosome at what is known as the fragile site
(Xq27.3).
• The typical phenotype includes a large, long head
and ears, short stature, hyperextensible joints,
and postpubertal macroorchidism.
• The mental retardation ranges from mild to
severe.

21. Martin-Bell
syndrome
Fragile X syndrome is believed to
occur in about 1 of every 1,000
males and 1 of every 2,000
females.

22. Fragile X Syndrome

23. Prader-Willi Syndrome
• Prader-Willi syndrome is postulated to result
from a small deletion involving chromosome 15,
usually occurring sporadically.
• Its prevalence is less than 1 of 10,000.
• Persons with the syndrome exhibit compulsive
eating behavior and often obesity, mental
retardation, hypogonadism, small stature,
hypotonia, and small hands and feet.
• Children with the syndrome often have
oppositional and defiant behavior.

24. Prader-Willi Syndrome

25. Cat's Cry (Cri-du-Chat) Syndrome
• Children with cat's cry syndrome lack part of
chromosome 5.
• They are severely retarded and
show many signs often associated with
chromosomal aberrations, such as microcephaly,
low-set ears, oblique palpebral fissures,
hypertelorism, and micrognathia.
• The characteristic cat-like cry caused by laryngeal
abnormalities that gave the syndrome its name
gradually changes and disappears with increasing
age.

26. Cri-du-Chat Syndrome

27. Cri-du-Chat Syndrome

28. Phenylketonuria
• PKU was first described by Ivar Asbjörn Fölling in
1934 as the paradigmatic inborn error of
metabolism. PKU is transmitted as a simple
recessive autosomal mendelian trait and occurs
in about 1 of every 10,000 to 15,000 live births.
• The basic metabolic defect in PKU is an inability
to convert phenylalanine, an essential amino
acid, to paratyrosine because of the absence or
inactivity of the liver enzyme phenylalanine
hydroxylase, which catalyzes the conversion.

30. Phenylketonuria
• Most patients with PKU are severely retarded,
but some are reported to have borderline or
normal intelligence. Eczema, vomiting, and
convulsions occur in about a third of all patients.
• They frequently have temper tantrums and often
display bizarre movements of their bodies and
upper extremities, including twisting hand
mannerisms; their behavior sometimes
resembles that of children with autism or
schizophrenia.

32. Rett's Disorder
• Rett's disorder is hypothesized to be an X-
linked dominant mental retardation syndrome
that is degenerative and affects only females.
• Deterioration in communications skills, motor
behavior, and social functioning starts at
about 1 year of age. Autistic-like symptoms
are common, as are ataxia, facial grimacing,
teeth-grinding, and loss of speech.

33. Rett's Disorder

34. Neurofibromatosis
• Also called von Recklinghausen's disease,
neurofibromatosis is the most common of the
neurocutaneous syndromes caused by a single
dominant gene, which may be inherited or be a
new mutation. The disorder occurs in about 1 of
5,000 births. and is characterized by cafe au lait
spots on the skin and by neurofibromas, including
optic gliomas and acoustic neuromas, caused by
abnormal cell migration.
• Mild mental retardation occurs in up to one third
of those with the disease.

36. Tuberous Sclerosis
• Tuberous sclerosis is the second most
common of the neurocutaneous syndromes; a
progressive mental retardation occurs in up to
two thirds of all affected persons.
• It occurs in about 1 of 15,000 persons and is
inherited by autosomal dominant
transmission.

37. Tuberous Sclerosis

38. Lesch-Nyhan Syndrome
• Lesch-Nyhan syndrome is a rare disorder
caused by a deficiency of an enzyme involved
in purine metabolism.
• The disorder is X-linked; patients have mental
retardation, microcephaly, seizures,
choreoathetosis, and spasticity.

39. Lesch-Nyhan
Syndrome

40. Adrenoleukodystrophy
• The most common of several disorders of
sudanophilic cerebral sclerosis,
adrenoleukodystrophy is characterized by diffuse
demyelination of the cerebral white matter
resulting in visual and intellectual impairment,
seizures, spasticity, and progression to death.
• The disorder is transmitted by a sex-linked gene
located on the distal end of the long arm of the X
chromosome.
• The clinical onset is generally between 5 and 8
years of age, with early seizures, disturbances in
gait, and mild intellectual impairment.

41. Adrenoleukodystrophy
• The story of a child
with the disorder
was presented in
the 1992 film
Lorenzo's Oil.

42. Maple Syrup Urine Disease
• An inborn error of metabolism caused by
defective oxidative decarboxylation of )-keto
acids of leucine, isoleucine, and valine.
• These branched-chain amino acids are
present in the blood and urine in high
concentrations.
• Manifestations of disease include feeding
difficulties, physical and mental retardation,
and a urine odor similar to that of maple
syrup; neonatal death is common.

43. Acquired and Developmental Factors
• Prenatal Period
• Rubella (German Measles)
• Cytomegalic Inclusion Disease
• Syphilis
• Toxoplasmosis
• Herpes Simplex
• Acquired Immune Deficiency Syndrome (AIDS)

44. • Fetal Alcohol Syndrome
• Prenatal Drug Exposure
• Complications of Pregnancy
• Perinatal Period
• Acquired Childhood Disorders
• Infection
• Head Trauma
• Other Issues

45. Prenatal Period
• Maternal chronic illnesses affecting the normal
development of the fetus's CNS include
uncontrolled diabetes, anemia, emphysema,
hypertension, and long-term use of alcohol and
narcotic substances.
• The extent of fetal damage depends on the type
of viral infection, the gestational age of the
fetus, and the severity of the illness.

46. Rubella (German Measles)
• the major cause of mental retardation caused
by maternal infection.
• The children of affected mothers may show
several abnormalities, including congenital heart
disease, mental retardation, cataracts, deafness,
microcephaly, and microphthalmia.
• The incidence rises to almost 50 percent when
the infection occurs in the first month of
pregnancy.

47. Cytomegalic Inclusion Disease
• Some children are stillborn, and others have
jaundice, microcephaly, hepatosplenomegaly,
and radiographic findings of intracerebral
calcification.
• The diagnosis is confirmed by positive findings
of the virus in throat and urine cultures.

48. Syphilis
• The incidence of
syphilitic
complications of
pregnancy
fluctuates with
the incidence of
syphilis in the
general
population.

49. • Toxoplasmosis
• It causes mild or severe mental retardation and,
in severe cases, hydrocephalus, seizures,
microcephaly, and chorioretinitis.
• Herpes Simplex
• The herpes simplex virus can be transmitted
transplacentally, although the most common
mode of infection is during birth.
• Microcephaly, mental retardation, intracranial
calcification, and ocular abnormalities may result.

50. Acquired Immune Deficiency
Syndrome (AIDS)
• Many fetuses of mothers with AIDS never come
to term because of stillbirth or spontaneous
abortion.
• Children born with HIV infection often live only a
few years; however, most babies born to HIV-
infected mothers are not infected with the virus.

51. Fetal Alcohol Syndrome
• A typical phenotypic picture
of facial dysmorphism that
includes hypertelorism,
microcephaly, short palpebral
fissures, inner epicanthal
folds, and a short, turned-up
nose.
• The entire syndrome occurs in
up to 15 percent of babies
born to women who regularly

52. Complications of Pregnancy
• Toxemia of pregnancy and uncontrolled
maternal diabetes result in mental
retardation.
• Maternal malnutrition during pregnancy often
results in prematurity and other obstetrical
complications.
• Vaginal hemorrhage, placenta previa,
premature separation of the placenta, and
prolapse of the cord can damage the fetal
brain by causing anoxia

53. Infection
• The most serious infections affecting
cerebral integrity are encephalitis and
meningitis.
• Most episodes of encephalitis are
caused by viruses.
• Sometimes a clinician must
retrospectively consider a probable
encephalitic component in a previous
obscure illness with high fever.

54. Head Trauma
• The best-known causes of head injury in
children that produces developmental
handicaps, including seizures, are motor
vehicle accidents, but more head injuries are
caused by household accidents, such as falls
from tables, from open windows, and on
stairways.

56. Diagnosis
• History
• The history is most often obtained from the
parents or the caretaker, with particular
attention to the mother's pregnancy, labor, and
delivery.
• The clinician assesses the overall level of
functioning and intellectual capacity of the
parents and the emotional climate of the home.

57. Diagnosis
• Psychiatric Interview
• Two factors are of paramount importance when
interviewing the patient:
• 1) the interviewer's attitude .
• 2) manner of communicating.
• A mildly retarded adult with a mental age of 10 is
not a 10-year-old child.
• When addressed as if they were children, some
retarded persons become justifiably insulted,

58. • The patient's verbal abilities, including receptive
and expressive language, should be assessed as
soon as possible by observing the
communication between the caretakers and the
patient and by taking the history.
• The interviewer and the caretaker should
attempt to give such patients a clear, supportive,
concrete explanation of the diagnostic process,
particularly patients with sufficiently receptive
language.

59. • The use of speech, reality testing, and the
ability to generalize from experiences should
be noted.
• Frustration, tolerance, and impulse control,
especially over motor, aggressive, and sexual
drive should be assessed.

60. Physical Examination
• the configuration and the size of the head
offer clues to a variety of conditions, such as
microcephaly, hydrocephalus, and Down
syndrome.
• patient's face may have some signs of mental
retardation that greatly facilitate the
diagnosis, such as hypertelorism, a flat nasal
bridge, prominent eyebrows, epicanthal folds,
corneal opacities, retinal changes.

61. • The circumference of the head should be
measured as part of the clinical investigation.
• Dermatoglyphics may offer another diagnostic
tool, because uncommon ridge patterns and
flexion creases on the hand are often found in
persons who are retarded.

62. • Table 38-4 Representative Sample of Mental
Retardation Syndromes and Behavioral
Phenotypes

63. Neurological Examination
• Sensory impairments occur frequently among
persons who are mentally retarded.
• Disturbances in motor areas are manifested in
abnormalities of muscle tone (spasticity or
hypotonia), reflexes (hyperreflexia), and
involuntary movements (choreoathetosis).

64. • In older children, hyperactivity, short attention
span, distractibility, and a low frustration
tolerance are often signs of brain damage.
• The younger the child at the time of
investigation, the more caution is indicated in
predicting future ability, because the recovery
potential of the infantile brain is very good.

65. • Skull X-rays: craniosynostosis, hydrocephalus,
and intracranial calcifications.
• Computed tomography (CT) scans and magnetic
resonance imaging (MRI) : CNS pathology
associated with mental retardation.
• An EEG is best interpreted with caution in cases
of mental retardation.
• exceptions are patients with hypsarhythmia and
grand mal seizures, in whom the EEG may help
establish the diagnosis and suggest treatment

66. Clinical Features
• Mild mental retardation may not be diagnosed until
the affected children enter school; their social skills
and communication may be adequate in the
preschool years.
• Moderate mental retardation is likely to be
diagnosed at a younger age than mild mental
retardation; communication skills develop more
slowly in persons who are moderately retarded, and
their social isolation may begin in the elementary
school years.
• Severe mental retardation is generally obvious in

67. Laboratory Examination
• chromosomal analysis,
• urine and blood testing for metabolic
disorders,
• neuroimaging.
• Chromosomal abnormalities are the single
most common cause of mental retardation
found in individuals for whom a cause can be
identified.

68. Chromosome Studies
• Amniocentesis, in which a small amount of
amniotic fluid is removed from the amniotic
cavity transabdominally at about the 15th week
of gestation, has been useful in diagnosing
prenatal chromosomal abnormalities.
• it should be considered by pregnant women over
the age of 35.
• Chronic villi sampling (CVS) is a screening
technique to determine fetal chromosomal
abnormalities.
• 8 to 10 weeks of gestation

69. Urine and Blood Analysis
• Lesch-Nyhan syndrome,
• Galactosemia,
• PKU,
• Hurler's syndrome,
• Hunter's syndrome,
• Unexplained growth abnormality,
• Seizure disorder,
• poor muscle tone, ataxia, bone or skin
abnormalities, and eye abnormalities are some
indications for testing metabolic function.

70. Neuroimaging
• Biological mechanisms contributing to mental
retardation syndromes.
• MRI can show abnormalities in the brain such
as myelination patterns.

71. Two brothers, age 6 and 8 years, with Hunter's syndrome, shown with their
normal older sister. They have had significant developmental delay, trouble
with recurrent respiratory infection, and behavioral abnormalities.

72. Hearing and Speech Evaluations
• Speech development may be the most reliable
criterion in investigating mental retardation.
• The commonly used methods of hearing and
speech evaluation, however, require the
patient's cooperation and, are often unreliable
in severely retarded persons.

73. Psychological Assessment
• the Goodenough Draw-a-Person Test, the Kohs
Block Test, and geometric puzzles all may be
used as quick screening tests of visual-motor
coordination.
• The Gesell and Bayley scales and the Cattell
Infant Intelligence Scale are most commonly
used with infants.
• For children, the Stanford-Binet Intelligence Scale
and the third edition of the Wechsler Intelligence
Scale for Children (WISC-III) are those most

74. Psychological Assessment
• Some persons have tried to overcome the
language barrier of persons who are mentally
retarded by devising picture vocabulary tests,
of which the Peabody Vocabulary Test is the
one most widely used.
• The tests often found useful in detecting brain
damage are the Bender Gestalt Test and the
Benton Visual Retention Test

75. Differential Diagnosis
• Several sensory disabilities, especially
deafness and blindness, can be mistaken for
mental retardation.
• Speech deficits .
• cerebral palsy .
• Convulsive disorders.
• Chronic brain syndromes can result in isolated
handicap failure to read (alexia), failure to
write (agraphia), failure to communicate
(aphasia),

76. • Mental retardation and pervasive
developmental disorders often coexist;
• 70 to 75 percent of those with pervasive
developmental disorders have an IQ below 70.
• A most difficult differential diagnostic problem
concerns children with severe mental
retardation, brain damage, autistic disorder,
schizophrenia with childhood onset, or,
according to some, Heller's disease.

77. • Children under the age of 18 years who meet
the diagnostic criteria for dementia and who
have an IQ below 70 are given the diagnoses
of dementia and mental retardation.

78. Treatment
• based on an assessment of social, educational,
psychiatric, and environmental need.
• Primary Prevention
• education to increase the general public's
knowledge and awareness of mental retardation;
• continuing efforts of health professionals to
ensure and upgrade public health policies;
• legislation to provide optimal maternal and child
health care

79. Treatment
Secondary and Tertiary Prevention
• should be treated to shorten
the course of the illness.
• to minimize the sequelae or
consequent disabilities.
• Hereditary metabolic and
endocrine disorders, such as
PKU and hypothyroidism, can
be treated effectively in an
early stage.

80. Treatment
• Education for the Child
• Behavioral, Cognitive, and
Psychodynamic Therapies
• Family Education
• Social Intervention

81. Treatment
• Pharmacology
• some studies have focused on
the use of medications for the
following behavioral syndromes
that are frequent among
persons who are mentally
retarded

82. Treatment
• Common Comorbid Psychiatric
Disorders
• Attention-Deficit/Hyperactivity
Disorder: methylphenidate
(Ritalin), risperidone (Risperdal)
• 1.6 mg a day for a period of 1
year
• Aggression and Self-Injurious
Behavior:
• lithium (Eskalith),

83. Treatment
• Note: Persons with mental
retardation appear to be at
higher risk for the development
of tardive dyskinesia after use of
a variety of antipsychotic
medications.
• For tardive dyskinesia-
risperidone and clozapine

84. Treatment
• Depressive Disorders
• SSRIs (e.g., fluoxetine [Prozac],
paroxetine, sertraline [Zoloft]) .
• Explosive Rage Behavior
• Adrenergic receptor antagonists
(beta-blockers), such as
propranolol (Inderal),
• Antipsychotic medications

85. ICD-10
• Approaches the diagnosis of mental
retardation from a somewhat different
viewpoint than DSM-IV-TR.
• According to ICD-10, mental retardation is a
condition arrested or incomplete
development of the mind• characterized by
impaired developmental skills that contribute
to the overall level of intelligence.

87. Services and Support for Children with
Mental Retardation
• Early Intervention
• School
• Supports

88. THANK YOU…!!

89. Maraming
Salamat
Po!