1. Intellectual Disability (Mental Retardation) (Mental Handicap)by
Dr. Azher Shah
Associate Professor
Department of Paediatric Medicine
Azra Naheed Medical College, Lahore

2. Introduction
Intellectual disability (ID) is a static encephalopathy with multiple etiologies that encompasses a broad spectrum of functioning, disability, and strengths
The term is synonymous with and is now preferred over the older term, mental retardation
The term global developmental delay is usually used to describe children younger than age five with significant cognitive deficits
ID is an important public health issue because of its prevalence and the need for extensive support services
Management requires early diagnosis and intervention

3. Definitions
A state of functioning that typically begins in childhood and is characterized by limitations in intelligence and adaptive skills
Two definitions are commonly used
Published by the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, text revision (DSM–IV)
Published by the American Association on Intellectual and Developmental Disabilities (AAIDD)

4. DSM-IV Definition
Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM- IV) uses the term mental retardation instead of intellectual disability
Defines by three co-existing criteria
Significant sub-average intellectual function
Significant limitations in adaptive functioning
Onset before 18 years of age

5. DSM-IV Definition (Cont…)
Cognitive / Intellectual Impairment
Severity of cognitive impairment is characterized by the extent of deviation of the IQ below 100
Lower limit of normal is considered to be two standard deviations below the mean or an IQ of 70
Gradations of severity include IQs in the following ranges
Mild – between 50 to approximately 70
Moderate – between 35 to 50
Severe – between 25 to 35
Profound – below 25
Unspecified – not readily testable but presumed low (ie, <70)

6. DSM-IV Definition (Cont…)
Adaptive Skills
Skills of daily living that are needed to live, work, interact, and play in the community
Examples are
Communication, social and interpersonal skills, self-care, home living, use of community resources, self-direction, functional academic skills (reading, writing and basic mathematics), work, leisure, health and safety
Adaptive functioning is considered to be impaired when there is a deficit in at least two of these areas

7. AAIDD Definitions (Cont…)
American Association on Intellectual and Developmental Disabilities (AAIDD) Definition
AAIDD encourages the use of the term "intellectual disability" in place of "mental retardation"
Intellectual disability is characterized as "significant limitations both in intellectual functioning (reasoning, learning, problem solving) and in adaptive behavior, which covers a range of every day social and practical living skills" with onset before 18 years of age
Assumptions to the application of the AAIDD definition
Limitations in function must be assessed relative to the child's age, culture, experience, and environment
An important purpose of characterizing limitations is to identify supports that are needed

8. Syndromic vs Non- syndromic Intellectual Disability
Syndromic ID (S-ID) is applied when a child presents with ID in addition to one or more clinical abnormalities or comorbidities of a known syndrome
Non- syndromic ID (NS-ID) is usually applied when a child presents with ID alone

9. Global Developmental Delay
Terms intellectual disability (ID) or mental retardation usually are applied to children older than five years of age, when IQ testing is more reliable
Preferred term in younger children with significant deficits in learning skills and adaptation is global developmental delay
Global developmental delay has been defined as performance at least two standard deviations below the mean, using standardized age-appropriate and developmentally appropriate criteria, in at least two of the following developmental subscales - Motor (gross/fine), speech and language, cognition, social, and daily living skills
Terms global developmental delay and ID are not interchangeable

10. Epidemiology
Prevalence of ID in the general population is estimated to be approximately 1 percent and ID is mild in approximately 85 percent of affected individuals
Prevalence varies with age and gender and is highest in school-age and male populations
Prevalence of mild ID is more variable than severe ID, varying with environmental factors of maternal education, educational access, or opportunities and access to healthcare
ID, and mild ID in particular, is more prevalent in developing countries or areas with lower socioeconomic status
In children less than five years of age, the prevalence of global developmental delay is estimated at 1 to 3 percent

11. Etiology
Identifying a cause enables appropriate counseling, focused interventions, treatments
Genetic causes may have implications for future pregnancies, and there may also be reproductive implications for the extended family
Causes usually are classified according to the time of the insult, as prenatal, perinatal, and postnatal or acquired
Some causes, such as environmental toxins or endocrine disorders, may act at multiple times
In many cases, no etiology can be identified despite extensive evaluation

12. Prenatal Causes (Genetic)
Etiology
Prenatal Causes (Genetic)
Chromosomal microarray testing is currently the most valuable tool to identify genetic causes of ID  
Genetic abnormality may have different phenotypes or clinical expressions and may present as ID alone (non-syndromic ID), or as ID associated with a clinical syndrome (syndromic ID)
Known genetic disorders or conditions include
Chromosomal abnormalities (Down syndrome or Trisomy 21)
X-linked disorders (Fragile X syndrome)
Autosomal recessive disorders (Metabolic disorders)
Autosomal dominant disorders

13. Prenatal Causes (Non Genetic)
Etiology
Prenatal Causes (Non Genetic)
Central nervous system (CNS) malformations
Congenital infection
Environmental toxins or teratogens (eg, alcohol, lead, mercury, hydantoin, valproate)
Radiation exposure (especially between 9 and 15 weeks of gestation)
Congenital hypothyroidism
Inborn errors of metabolism (phenylketonuria)

14. Etiology Preterm birth Hypoxia Infection Trauma
Perinatal Causes
Preterm birth
Hypoxia
Infection
Trauma
Intracranial haemorrhage

15. Etiology Postnatal Causes Accidental or non accidental trauma
CNS haemorrhage
Hypoxia (eg, near-drowning)
Environmental toxins
Psychosocial deprivation
Malnutrition
Intracranial infection
CNS malignancy
Acquired hypothyroidism

16. Risk Factors Male gender Low-birth-weight infants
Higher and lower maternal age
Low maternal education
Multiple births
Children of consanguineous parents

17. Clinical Presentation
Language delay
Immature behaviour
Immature self-help skills
Difficulty in learning
Delayed development

18. Clinical Presentation
Associated Conditions
Autism and other behavioral disorders
Seizure disorders
Motor handicaps affecting gross, fine, and speech motor functions
Problems with vision, hearing
Abnormal thyroid function
Short stature
Growth hormone deficiency

19. Clinical Presentation
Mental disorders
Affect approximately 30 to 70 percent of children with ID
Affect functioning, quality of life, and adaptation

20. Diagnosis
Diagnosis of ID is based on measures of intellectual and adaptive function through a battery of standardized tests
Selection of the appropriate testing instruments depends on the child's age, culture, language, socioeconomic status, and personal handicaps, including motor, sensory, and communication disorders
For tests of intellectual function, the lower limit of normal is considered to be two standard deviations below the mean, or an intelligence quotient (IQ) of 70
Tests of adaptive function are used to assess for deficits in conceptual skills (eg, receptive and expressive language, reading and writing, and money concepts), social skills (eg, interpersonal skills, responsibility, gullibility, and obedience of laws), and practical daily living skills (eg, eating, dressing, toileting, preparing meals, and using transportation)

21. Management of Intellectual Disability

22. Goals of Management Strengthen areas of reduced function
Prevent or minimize further cognitive-adaptive deterioration relative to peers
Promote optimal functioning in society
Provide ongoing family support

23. General Measures of Management
Require ongoing health surveillance similar to normal children
Developmental, academic, and psychosocial progress should be monitored
Evaluation of nutritional status to ensure a well-balanced diet
Vigilant surveillance should be maintained to detect and prevent abuse and neglect
Family Psychosocial Screen may be helpful to screen families for concerns of abuse and maternal depression

24. General Measures of Management
Require a broad range of interventions that should be applied early to improve short-term and long-term outcomes
Speech and language therapy
Occupational therapy
Physical therapy and rehabilitation, including mobility and postural support
Family counseling and support
Behavioral intervention
Educational assistance
Parent support, information, and advocacy (Support groups)

25. Specific Interventions
If an underlying cause is identified, it should be promptly treated
Phenylketonuria
Hypothyroidism
Hydrocephalus

26. Specific Interventions
Associated conditions should be treated in order to maximize functioning
Cataracts
Vision and hearing impairments
Congenital heart disease
Seizures
Constipation

27. Specific Interventions
Patients with ID due to specific conditions may have characteristic sleep disorders
Smith Magenis syndrome is associated with insomnia
Prader-Willi or Down syndrome are at risk for obstructive sleep apnea
These children require sleep-related behaviour interventions or counseling

28. Specific Interventions
Lead screening should be obtained for possible exposure and re-exposure

29. Behavioural Interventions
Needed to improve socialization skills and behavioral functioning in children with ID
These are individualized and applied consistently to encourage appropriate thinking, expression, adaptive function, conduct, and environmental manipulation
Interventions should be appropriate to the child's level of functioning (particularly language functioning) rather than chronological age
Desirable behaviors should be positively reinforced

30. Behavioural Interventions
Active intervention to reduce antecedents (triggers) of problem behaviors
Reinforcement of acceptable behavior by providing positive attention ("time in" attention) or desired reinforcer (appropriate treat or preferred activity)
Purposeful "ignoring" of behaviors to encourage their non-use (as long as the behavior is not dangerous)
Redirecting attention to extinguish problem behaviors

31. Behavioural Interventions
Reinforcing behaviors incompatible with problem behaviors
Prompt removal of the child from an activity when a targeted problem behavior occurs ("time out")
Promotion of good self-esteem and independence
Child should also be taught how to resist peer pressure and avoid exploitation
For adolescents, individualized teaching should include issues of sexuality, transition to adult life, and preparation for independent community living
Group psychotherapy

32. Early Intervention Programme Models
Case management
Speech and language therapy
Occupational and physical therapy
Psychological services
Health services, including hearing and vision
Nutrition counseling
Assistive technology (which may include tape-recorded texts, reading scanners, or voice-activated computer programs)
Medical diagnostic services
Transportation and other assistive technology
Interventions for the family include
Counseling
Training
Home visitation
Social services

33. Outcome
Variable and depends upon the etiology, associated conditions, environmental and social factors
Environmental factors such as education and rehabilitation
Social factors such as caregiver support, expectations, attitudes, socioeconomic characteristics and social opportunities

34. Outcome ( According to the DSM definitions)
Mild ID
Have a developmental velocity of one-half to two-thirds the average rate, accomplishing third to sixth grade level reading skills by late adolescence
Some mildly affected individuals can work at regular occupations, and many live independently
Many marry and become parents, although raising children is challenging

35. Outcome ( According to the DSM definitions)
Moderate ID
Develop at one-third to one-half the expected rate of normal children
School based academic and social development gains are slow
Reading at a first to third grade level can be accomplished with educational services
Teaching is needed for daily living skills.
Majority need sheltered or supportive employment positions, although some can perform unskilled work
Few are able to marry and raise children

36. Outcome ( According to the DSM definitions)
Severe ID
Developmental progress for children with severe ID is approximately one-quarter to one-third of the expected rate
Speech development may be delayed until four to five years of age, or may never occur
Majority require training in social and self-help daily living skills
Majority need assistance with daily living and adult social skills
In general, severely affected individuals do not marry or raise children

37. Outcome ( According to the DSM definitions)
Profound ID
Develop at less than one-quarter of the typical rate
They need comprehensive assistance that is tailored to their physical needs
Need assistance in all aspects of daily living
Profoundly affected individuals cannot acquire reading skills
Life expectancy of children with profound ID varies and is up to 20 years

38. Prevention (Most causes of ID cannot be prevented)
Aimed at preventing conditions that may cause ID
Primary prevention
Avoidance of prenatal exposure to alcohol or other toxins
Use of prenatal Multivitamins, especially Folic acid
Appropriate prenatal care
Newborn screening programs for metabolic disease
Routine childhood immunizations
Use of car seats and restraints
Prevention of motor vehicle accidents, violence, and other trauma

39. Prevention (Most causes of ID cannot be prevented)
Genetic forms of ID could be addressed by the following measures
Provision of clinical genetics services to facilitate accurate genetic diagnosis and counseling
Genetic counseling may enable estimation of recurrence risks and about reproductive options in the future
Pre-implantation genetic diagnosis (PGD) and prenatal diagnosis

40. Prevention (Most causes of ID cannot be prevented)
Directed at treating an underlying condition
Secondary prevention
Lead surveillance in a child at risk for lead exposure
Dietary restriction in metabolic diseases such as phenylketonuria or galactosemia
Thyroid hormone replacement in a hypothyroid child
Treatment of associated conditions including vision and hearing impairment, seizures, and other co-morbid medical disorders

41. Prevention (Most causes of ID cannot be prevented)
Aimed at maximizing function and quality of life
Tertiary prevention
Early identification of affected individuals
Access to and provision of appropriate comprehensive services and resources
Treatment of comorbid conditions
Prevention and treatment of psychosocial disorders

42. Thank you