Module 3 Chapters 5 & 6 PDF

CHAPTER 5: INTELLECTUAL DISABILITY AND DEVELOPMENTAL DISORDERS Describe the key features of intellectual disability and the way in which children with this condition can vary in terms of their adaptive functioning. ID is a spectrum ranging from severe disabilities to mild indistinguishable d...

CHAPTER 5: INTELLECTUAL DISABILITY AND DEVELOPMENTAL DISORDERS Describe the key features of intellectual disability and the way in which children with this condition can vary in terms of their adaptive functioning. ID is a spectrum ranging from severe disabilities to mild indistinguishable delays. Children have diverse outcomes (multifinality) and many participate in regular everyday activities and have families of their own later on All individuals with ID have significantly low intellectual functioning and have problems perceiving and processing new info, learning quickly and efficiently, applying knowledge and skills to solve novel problems, thinking creatively and flexibly, and responding rapidly and accurately Children 5 and older → intellectual functioning is measured using a standardized, individually administered IQ test. Scores are normally distributed with a mean of 100 and an SD of 15. IQ below 70 may be considered an intellectual disability, with a measurement error of 5 points (we might use an IQ of 65 to 75 as the cutoff) ○ 2-3% of the pop. sees IQs below this ID → significant deficits in adaptive functioning, which is the typical level of success in meeting the day-to-day demands of society in an age-appropriate manner ○ DSM-5 identifies 3 domains of adaptive functioning → conceptual, social, and practical. To be diagnosed with an ID you must show impairment in at least one domain, and children usually show impairment in multiple areas Conceptual skills → understanding language, speaking, reading, writing, counting, telling time, solving math problems, having the ability to learn and remember new info and skills Social skills → having interpersonal skills, following rules, engaging in social problem-solving, understanding others, making and keeping friends Practical skills → activities of daily living and functioning including taking personal care, practicing safety, doing home activities, having school/work skills, participating in rec activities, and using money The DSM-5 also says that onset of intellectual and adaptive deficits have to happen during the developmental period  Adaptive functioning can be assessed by interviewing caregivers about the children’s behaviour and comparing their reports to the behaviour of typically developing children of the same age and cultural group A norm-referenced interview/scale like the Diagnostic Adaptive Behaviour Scale (DABS) can be administered to caregivers to collect info about their child’s adaptive functioning. DABS is semistructured and is used to help the interviewer rate children’s adaptive behaviour across conceptual, social, and practical domains. The DABS provides standard scores, and a score more than 2 SD;s below the mean in at least one domain can indicate impairment in adaptive functioning An ID is characterized by low IQ AND problems in adaptive functioning. An IQ of 65 with no problems in adaptive functioning would not be enough for an ID diagnosis Mild intellectual disability (adaptive functioning scores 55-70) ○ As infants and toddlers, usually appear no diff than others without an ID ○ Achieve most developmental milestones at expected ages, learn basic language, and interact with family members and peers ○ Intellectual deficits usually first noticed when they begin school by teachers; may require more time and practice to master academic skills like letter and number recognition, reading, and math ○ As school work becomes more challenging, children with an ID may fall behind others and need to repeat grades ○ Some children become frustrated with traditional education and display behaviour problems in class ○ Middle school → basic reading and math is mastered but further academic progress is seldom achieved ○ After school → typically blend back into society, perform semiskilled jobs, and live independently in the community. Only occasional support is usually required from others to overcome their intellectual deficits (ex. They may need help completing a job application, filing a tax return, or managing their finances) Moderate (Adaptive functioning scores 40-55) ○ Conceptual → preschoolers language and pre-academic skills develop slowly. School aged-children show slow progress in academic skills. Academic skill development is usually at the elementary level  ○ Social → marked differences in social and communicative skills compared to peers. Spoken language is simplistic and concrete. Social judgment and decision making are limited. Friendships are often affected by social or communicative deficits ○ Practical → needs more time and practice learning self-care skills, such as eating, dressing, toileting, and hygiene, than peers. Household skills can be acquired by adolescent with ample practice Severe (adaptive functioning scores 35-40) ○ Conceptual → the child generally has little understanding of written language or numbers. Caretakers must provide extensive support for problem solving throughout life ○ Social → limited spoken language skills with simplistic vocab and grammar. Speech may be single words/phrases. Child understands simple speech and gestures. Relationships are with family members and other familiar people ○ Practical → needs ongoing support for all activities of daily living; eating, dressing, bathing, elimination. Caregivers must supervise at all times. Some youths show challenging behaviours, such as self-injury Profound (adaptive functioning scores less than 25) ○ Conceptual → generally involve the physical world rather than symbols. Some visual-spatial skills, such as matching and sorting, may be acquired with practice. Co-occurring physical problems may greatly limit physical functioning ○ Social → the child has limited understanding of symbolic communication. The child may understand some simple instructions and gestures. Communication is usually through nonverbal, non-symbolic means. Relationships are usually with family members and other familiar people. Co-occurring physical problems may greatly limit functioning ○ Practical → the child is dependent on others for all aspects of physical care, health, safety, although they may participate in some aspects of self-care. Some youths show challenging behaviours, such as self-injury. Co-occurring physical problems may greatly limit functioning The american association on intellectual developmental disabilities has a lot of overlap with the DSM-5, but more greatly emphasizes needed supports. Needed supports can be supports provided by health care providers, mental health professionals, teachers,  educational specialists, professional caregivers, or human service agencies. Supports can be informal help from parents, friends, or community members ○ AAIDD designates 4 possible levels of support Intermittent (occasional, in time of crisis) Limited (short-term) Extensive (long-term) Pervasive (constant) ○ AAIDD recommends that professionals describe individuals’ need for supports across various areas of functioning, rather than categorize into mild, moderate, severe, and profound A child may require extensive academic support but only intermittent social support ○ The Supports Intensity Scale from the AAIDD measures support needed in areas of home living, community living, lifelong learning, employment, health and safety, social activities, and protection and advocacy. Each activity is ranked according to 1) frequency, 2) amount, and 3) type of support needed Two main advantages of classifying individuals with ID in terms of needed support: 1) conveys more info about clients than simply classifying them with ID alone and 2) focuses on clients’ abilities rather than on their impairments Drawbacks to this approach? 1) It is complex. Describing clients on so many dimensions is cumbersome and can hinder communication among professionals. 2) it can make research difficult. With so many combos of needed supports and areas of functioning, it can be difficult to identify a homogenous group of individuals for study Differentiate intellectual disability from global developmental delay. Identifying IDs in very young children is difficut, as they may not be advanced enough to perform on many IQ tests meant for older children and adolescents GDD is a neurodevelopmental disability only diagnosed in children less than 5 years old ○ The infant or child fails to meet developmental milestones in several areas and a professional suspects ID; however, an individual IQ test cant be administered  because the child is so young. GDD is assigned as a temporary diagnosis until he child is old enough to take IQ tests ○ Usually diagnosed in infants and toddlers who show significant delays in two or more domains: 1) fine/gross motor skills, 2) speech/language, 3) social/personal skills, and 4) daily living. Significant delay = scores two or more SDs below the mean. Children with GDD typically show delays across most or all domains ○ Usually identified in the first year of life, some show physical abnormalities at birth, others show apparent delays only when caregivers notice their children are not developing in the same way as other children ○ Children with GDD usually do not catch up with their typically developing peers, and are more often than not diagnosed with an ID once they are preschool age (or meet criteria for it). Because of this, GDD is often considered a “placeholder” diagnosis for children too young to be diagnosed with an ID Not always the case though. Children with cerebral palsy often also show developmental delays often accompanied by intellectual deficits Social deprivation or severe economic hardship can also lead to early delays in motor, language, and cognitive development. Proper care provided especially before 9 months can remedy these deficits ○ Not all children with GDD have concurrent deficits in intellectual functioning. Many earn scores within the average range Identification 1-3% of infants and toddlers had GDD Sometimes the cause can be determining based on physical exams (ex. Down syndrome), but in most cases a blood test has to be ordered to screen for genetic disorders. A chromosomal microarray is recommended for infants with GDD ○ CMA identifies copy number variants in major regions of the genome Most common genetic disorders that cause GDD are down syndrome, fragile x syndrome, rett syndrome, and subtle translocations or deletions of portions of the genome ○ About 4% of children with GDD have an identifiable genetic disorder that explains their delays G-banded karyotyping produces a strained image of the child’s chromosomes and is useful for detecting gross genetic abnormalities. Alternatively, CMA screens the child’s genome and generates a high-resolution “virtual karyotype” that can detect small  repetitions or deletions of genetic material. CMA has largely replaced G-banded karyotyping Blood or urine tests can be ordered to screen for metabolic disorders like PKU, hypothyroidism, and lead poisoning that can cause delays. These are rare, and only seen in about 1% of youths with GGD If genetic and metabolic tests are negative, neuroimaging may be used → MRI for abnormalities like CNS malformation, cerebral atrophy, myelination problems, or cellular damage and lesions Sensory deficits must also be rules out as the underlying cause. 13-25% of children with GDD → vision problems and 18% → hearing problems List and provide examples of challenging behaviors shown by some children with developmental disabilities. Actions that are of such intensity, frequency, or duration that they significantly interfere with their safety or social functioning. About 25% of youths with an ID engage in challenging behaviours It can be physically harmful, strain relationships, limit access to normal childhood experiences, interfere with learning and cognitive development, and place a financial burden on the family and the public Stereotypies: behaviours that are performed in a consistent, rigid, and repetitive manner and that have no immediate practical significance ○ Repeated movements of the hands, arms, or upper body. Facial grimacing, face and head tapping, self-biting, and licking ○ Some dveeloping infants, toddlers, and even adolescents without an ID show repetitive behaviours. Theyre not problematic unless they come to dominate the youths’ behaviour, persist over time, and interfere with functioning. DSM-5 permits a stereotyped movement disorder when they become sufficiently impairing ○ Especially common in youths with ID AND autism ○ May be due to genetic disorders, but they are also self-reinforcing. They can make boring moments more pleasurable or relieve anxiety and frustration Self-Injurious Behaviours: repetitive movements of the hands, limbs, or head in a manner that can, or do, cause physical harm or damage to the person  ○ Classified in terms of 1) severity from mild to severe, 2) frequency from low-occurring with high potential for harm to high-occurence that may cause harm over time, and 3) purpose, whether its the responses they elicit from others or being reinforcing themselves ○ 10-12% of children with IDs engage and prevalence is directly related to the child’s intellectual and adaptive impairments ○ Most commonly seen in children with severe and profound impairments, in institutional settings, with autism ○ Head banging and self biting/scratching are the two most common ○ Usually occur in bouts or episodes several times a day, usually showing the same behaviours in each episode ○ Usually triggered by the environment and are maintained over time by biological factors ○ These behaviours can serve a certain purpose or function (soothing, communicative), be caused by a hypersensitivity to dopamine, or be maintained by high levels of endogenous opioids or endorphins (which may cause a higher tolerance to pain or pleasure to be derived from the behaviour) Physical Aggression: behaviour that causes property destruction or harm to another person ○ Throwing objects, breaking toys, ruining furniture, hitting, kicking, and biting others ○ Deliberately performed, but the intentions arent always clear ○ 20-25% of youths with ID show chronic problems with aggression, most common among boys, children with comorbid autism, and youths with poor communication skills. Invertly related to IQ scores ○ Some show aggression to avoid or escape a task, assignment, or chore. Often negatively reinforced by caregivers. Others engage to obtain an item or privilege they want. Others find it pleasurable to destroy things Comorbid Disorders Chidlren with IDs can suffer from the full range of psychiatric disorders (dual diagnosis) About 40% of children with an ID have a dual diagnosis. Most common is disruptive behaviour disorders, ADHD, and anxiety Diagnostic overshadowing: clinicials often overlook the presence of mental disorders in youths with ID. some dont have enough experience in assessing and treating people  with IDs, others attribute psychiatric problems to low intelligence or adaptive functioning issues How Common is Intellectual Disability? Some estimate the prevalence to be between 2-3% if we assume IQ scores are normally distributed in the population (with an ID being IQ less than 70) Others estimate is is more like 1.8% because IQ scores alone do not merit an ID diagnosis ○ A person’s IQ score can also fluctuate over time, especially if you score on the higher end of the ID continuum (55-70) ○ Life expectancy of a person with severe and profound impairment is less than that of a typical person, so the number of people with ID is liekly lower than expected based on the normal curve More frequently diagnosed among school-age children and teens than among adults ○ Cognitive impairments of people with an ID are more noticable wen people are in school Slighty more common in males than females (gender ration 1.3:1) ○ Male CNS may be more susceptible to damage? Males are more likely to show ID than females due to some abnormalities being on the X chromosome, making boys more susceptble? Distinguish between organic and cultural–familial intellectual disability. Zigler’s Classification Terms organic and cultural-familial are based solely on whether we can identify the cause of the ID. some cases of organic ID can be cuased by environmental factors (mother’s alcohol use during pregnancy), and vice-versa Organic ○ Child shows a clear genetic or biological cause for their ID ○ Usually diagnosed at birth or infancy, frequent comorbid disorders ○ IQ usually less than 50, siblings have a normal IQ, greater impairment in adaptive functioning, often dependent on others ○ Similar across ethnicities and SES groups, associated with health problems and physical diabilities, high mortality rate, unlikely to mate, often infertile, often have facial abnormalities  Cultural-Familial ○ Child shows no obvious cause for their ID, biological relatives may have low IQ ○ Usually diagnosed after beginning school, few comorbid disorders ○ IQ usually more than 50, siblings have low IQ, lesser impairment in adaptive functioning, can live independently with support ○ More prevalent in ethnic minorities and low-SES groups, usually few health problems and no physical disabilities, normal mortality rate, likely to marry and have children with low IQ, normal appearance Similar Sequence and Similar Structure Hypothesis Similar sequence hypothesis: Zigler proposed that children with ID progress through the same cognitive stages as typically developing children, just at a slower pace Similar structure hypothesis: Zigler suggested that the cognitive structures of children with ID are similar to the cognitive structures of typical children of the same mental age. A 16-y/o with intellectual functioning that resembles a 5-year-old should show the same pattern of cognitive abilities as a typically developing 5-year-old Research on children with cultural-familial ID has generally supported the similar sequence and similar structure hypotheses Children with organic ID do not typically follow an expected sequence, similar to that of typical children, and they tend to have differing cognitive strengths and weaknesses Behavioural Phenotypes Children with different types of organic ID show characteristic patterns of cognitive abilities. This is important because if characteristics associated with each known cause for ID could be identified, we could plan children’s education and improve their adaptive functioning ○ This is why researchers have moved away from studying “organic” disorders in a lump and instead focus on individual ones ○ Researchers want to establish a behavioural phenotype for children with each known cause of ID Would include appearance, overall intellectual and adaptive functioning, cognitive strengths and weaknesses, co-occurring psychiatric disorders, medical complications, and developmental outcomes Phenotypes are probabilistic Explain how genetic, metabolic, and environmental factors can lead to developmental disabilities in children. How Can Chromosomal Abnormalities Cause Intellectual Disability? More than 800 unique cases of ID that can be loosely organized into five categories: 1) chromosomal abnormalities, 2) x-linked disorders, 3) metabolic disorders, 4) embryonic teratogen exposure or illness, and 5) complications during or after delivery. These explain about 70% of ID cases Down Sydnrome Genetic disorder, moderate to severe ID, problems with language and academic functioning, characteristic physical features Likelihood of having a child with down syndrome depends on maternal age. Approx. 1/1000 live births 95% are caused by trisomy 21. Not inherited, caused by nondisjunction = a failure of the chromosome to separate during meiosis Can also occur due to inheriting an abnormally fused chromosome from one of the parents = a translocation → additional genetic material passed on to the child. THIS cause is inherited. Parents are usually unaffected carriers Can occur when some cells dont separate during mitosis, causing some normal cells and some abnormal cells with an abnormal amount of genetic info = chromosomal mosaicism Characteristic facial features → flattened face, slanting eyes, wide nasal bridge, low-set ears, short stature, poor muscle tone, small brain size and fewer folds and convolutions than in typical brains ○ Fewer folds suggests less surface area of the cortex, may be partially responsible for low intelligence Children with DS almost always diagnosed with an ID with an IQ under 60 Delays become more pronounced with age, more noticeable after child’s first birthday Significant deficits in language → simplistic grammar, limited vocabulary, impoverished sentence structure, impaired articulation Problems with auditory learning and short-term memory leads to struggles in traditional education settings Strengths in visual-spatial reasoning  Usually happy, social, and friendly, less likely to develop psychiatric disorders than other children with ID. may experience emotional and behavioural problems in teen years due to social isolation or increased self awareness Medical complications → congenital heart disease, thyroid abnormalities, respiratory problems, leukemia, Alzheimer’s disease after 40 (high incidence of tangles and plaques). Life expectancy is 65 Prader-Willi Syndrome Non-inherited genetic disorder → mild ID, overeating and obesity, oppositional behaviour toward adults, obsessive-compulsive behaviour 1/20,000 live births Usually caused by missing paternal genetic info. 1) deletion of genetic info on portions of chromosome 15, usually the father’s, so only 1 set of genetic info is inherited, or 2) mother contributes both pairs of chromosome 15 Mild to ID borderline intellectual functioning (IQ 65-70) with adaptive behaviour much lower Very strong visual-spatial skills, weakness in short-term memory Intense interest in food and inability to be satiated. Infants show problems with sucking, feeding, and gaining weight. Between 2-6 years → children eat enormous amounts of food (hyperphagia) ○ Might be abnormal functioning in hypothalamus, the brain area that controls hunger and satiation ○ Diet needs to be monitored; children will overeat, hoard food, steal food, etc ○ Onset of hyperphagia is associated with changes in behaviour → argumentative, defiant, temper tantrums, may destroy property or physically attack others ○ Most show obsessive thoughts or ritualistic, compulsive behaviours, usually around food but around other objects too Medical complications → obesity-related deaths Early adulthood → some show psychotic symptoms like distorted thinking and hallucinations (auditory or visual) Caused by abnormalities on portions of chromosome 15; inheriting only from the mother Angelman Syndrome Genetically based developmental disorder characterized by ID, speech impairment, happy demeanor, unusual motor behaviour. May look like “puppet children” 1/15,000-20,000 children have it  Caused by abnormalities on portions of chromosome 15; inheriting only from the father Wide smiling mouth, thin upper lip, pointed chin. Persistent social smile and happy demeanor seen between ages 1-3, later accompanied by giggling, laughing, and happy grimacing ○ Usually not recognised until toddlerhood, despite the social smiling Suspected when children continue to show cognitive impairment, lack of spoken language, and movement problems By childhood, usually severe or profound ID. youths show level of functioning similar to a 3 year ol ○ Children are usually unable to speak, some can use a few words meaningfully, can usually understand others and obey simple commands Hyperactivity and inattention, often interfering with ability to sleep and sustain attention. These problems continue through childhood but may decrease with age Hyperpigmentation common. Pale with light-coloured eyes. Gene that codes for skin colouring is deleted More than 90% have seizures. Life expectancy 10-15 years less than normal, depending on medical complications Williams Syndrome Genetic disorder, low intellectual functioning, hyperactivity, impulsivity, inattention, unusal strengths in spoken language and sociability. Broad foreheads, full lips, widely spaced teeth, star-shaped patterns in irises, elfin-like noses, eyes, and ears ○ Also hyperacusis = unusual sensitivity to loud noises Caused by a small deletion in a portion of chromosome 7. Approx. 1/20,000 live births Low IQ scores, poor visual-spatial abilities (due to portion of chromosome 7 being deleted) strengths in language; well-developed lexicons, complex storytelling with advanced vocab and grammar. Strengths in auditory memory and music, facial memory and inferring emotions based on affect, overly trusting of strangers Problems with anxiety that increase with age, very sensitive to failure and criticism by others, phobias common ○ Hyperacusis may be a risk factor for developing anxiety and fear of loud noises; balance problems might create fear of falling, social sensitivity may be a risk for social anxiety  Risk for cardiovascular problems due to insufficient elastin due to a portion of chromosome 7 being deleted 22q11.2 Deletion Syndrome Risk of developing an ID due to missing genetic material on one pair of 22nd chromosome. Most cases, genetic info is lost during fertilization Approx. 1 /2,000-4,000 children Cleft lip/palate, small ears, mouth, and chin, congenital heart problems, middle ear infections, hearing loss, immune problems, seizures ○ Language delays and learning problems, avg. IQ is 70 with significantly higher verbal skills than nonverbal skills One of the few known causes for schizophrenia. Problems understanding social situations and show impaired problem-solving. May develop autistic-like symptoms or be diagnosed with ADHD How Can X-Linked Disorders Cause Intellectual Disability? Disorders typically manifest differently across genders since boys have 1 X chromosome and girls have 2 Fragile X Syndrome Inherited genetic disorder associated with physical abnormalities, moderate - severe intellectual impairment, social/behavioural problems. 1 /4,,000 boys and 1 /8,000 girls Mutation in a gene on the x chromosome = fragile x mental retardation gene (FMR1). Children show an unusually high number of CGG repeats. Parents may carry these repeated sequences but show no symptoms and pass it on to their offspring, who will have more repeats (more than 200). The amount of FMRP produced is decreased. The less FMRP produced, the more severe the cognitive impairments ○ Abnormalities seen in the prefrontal cortex, caudate nucleus, and cerebellum presumably from less FMRP production ○ Called Fragile X because the X chromosome appears broken Boys and girls differ in presentation ○ Boys → more intellectual impairment, more severe behaviour problems, more physical anomalies, elongated heads, large ears, hyperflexible joints, large testicles after puberty, shorter than other boys, moderate to severe ID. perform well on tasks that require simultaneous processing and deficits in tasks that require sequential processing (arranging and processing info in a certain order).  Weaknesses in planning and organizing activities in an efficient manner. Medical problems → heart murmur and crossed eyes May display hyperactivity and inattention, reluctance to make eye contact or be touched by others, be extremely shy in social situations. As many as 90% also have ADHD, only about 25% meet criteria for autism ○ Girls → higher IQs, less noticeable physical anomalies, less severe behaviour problems. Display problems with attention, excessive shyness, gaze aversion, social anxiety Rett Syndrome (MECP-2 Disorder) Most common cause of severe ID in girls. Almost always caused by a genetic mutation in te MECP-2 gene of the x chromosome. Rarely inherited. Almost always seen in girls. 1 /8,500-10,000 children Infants display normal development for the first 6-18 months of life. Then they show a rapid deterioration in language, motor, and social skills. Most display social withdrawal and develop stereotypic hand-wringing movements. Often see health problems like growth failure, breathing problems, loss of movement, scoliosis. Often see emotional-regulation problems in toddlers. About 90% have seizures. Youth can live into adulthood with support from caregivers How Can Metabolic Disorders Cause Intellectual Disability? PKU (Phenylketonuria) → most well-known metabolic disorder that can lead to ID if untreated. Body’s inability to convert an amino acid into paratyrosine. The child doesnt produce the enzyme that breaks down phenylalnine, and as the child eats foods rich in this enzyme, the substance builds up and becomes toxic. Phenylalanine toxicity eventually causes brain damage and ID PKU is caused by a recessive gene, and the child must inherit it from both the mother and the father. Inheriting only one gene makes you a carrier. Occurs in approximately 1 /11,500 children Newborns are routinely screened for PKU through a blood test shortly after birth. If detected, the child is placed on an appropriate diet. Adherence to the diet results in normal intellectual development. Children on the diet are at risk for anemia and hypoglycemia ○ Youths who dont diet show symptoms a few months after birth. By childhood, they develop a severe ID, lack spoken language, are hyperactive, show erratic  movements, throw tantrums, experience gastrointestinal problems, and seizures. These impairments are irreversible, even if the diet is implemented later How Can Mental Illness or Environmental Toxins Cause Intellectual Disability? Maternal Illness Infections acquired by mothers during pregnancy can result in IDs TORCH: ○ Toxoplasma infection → caused by a parasite in warm-blooded animals. Can be encountered by consuming undercooked meat or handling animal droppings. Affects the development of the CNS. symptoms may not appear until late infancy or toddlerhood ○ Other infections → varicella zoster virus (causes chicken pox), syphilis, hep.B, HIV/AIDS. Get the chicken pox vaccine and limit contact with affected people. Antiviral meds during gestation, delivery by c-section, and bottle feeding can prevent the spread of sexual viruses. ○ Rubella → virus that causes german measles. Maternal symptoms are minor, but infants sho moderate to severe cognitive impairment. Infection is most serious during first trimester, more common in developing countries where the vaccine isnt as available ○ Cytomegalovirus (CMV) → very common virus most people get during teens or early adulthood. Causes mono. Can be transmitted to fetus if the mother gets ill for the first time during gestation. Can cause damage to the fetus’s CNS, hearing loss, ID, and death. Pregnant women should avoid anyone with symptoms of mono ○ Herpes 2 (HSV-2) → virus acquired typically through sexual contact. Approx. 20% of women aged 14-49 have it. Fetuses can acquire it if the mother first acquires it durin the final trimester of pregnancy or if the mother has an active breakout that comes into contact with the infant during delivery. Infants who acquire it can experience damage to their CNS, blindness, seizures, and ID. mothers can prevent fetal transmission by using antiviral meds and delivering by c-section Zika virus: acquired through infected mosquitos or sexual contact. Causes fever, rash, joint paint, and conjunctivitis in adults. Symptoms are usually minor. Fetuses can acquire  it during gestation, and experience severe damage to the developing CNS, microcephaly, cognitive impairment, and death Lead Exposure Lead is a neurotoxin that can cause developmental disabilities in children. Fetuses are at risk if mother is exposed to lead during gestation. Can happen through drinking contaminated water or working in industrial facilities. In high amounts, lead can pass through the placenta and affect fetal development. A history of lead exposure can also place the fetus at risk, as she may store it in her bones. If mom doesnt consume enough calcium during pregnancy, the body may substitute this stored lead for the calcium the baby needs. Newborns exposed during gestation are at risk for premature birth, low birth weight, and cognitive problems Children can be exposed through drinking contaminated tap water, playing near industrial sites that use lead in manufacturing, and (most commonly) ingesting lead-based paint. Older homes and apartments still contain lead-based paint. Typically measured with a blood test; even low levels are associated with neurodevelopmental problems in some children Effects can vary as a function of child age and amount and duration of exposure. Most dangerous to kids 0-5 years because of the rapid development of the nervous system during this time Strongly associated with cognitive problems, esp. Low intelligence and increased risk for learning disabilities. Deficits typically persist into adulthood Infants and toddlers exposed are at risk for behaviour problems, especially with attention and concentration, hyperactivity, and disruptive behaviour including aggression, and increased risk for conduct problems in teens Signs of lead toxicity in young children include cognitive delays, learning problems, irritability, sluggishness, loss of appetite, and gastrointestinal problems. Children with high levels can receive chelation therapy injected into the bloodstream. (only used in extreme instances. It can cause kidney damage, heart problems, and other metabolic issues) Alcohol and Other Drugs Many drugs are associated with low birth weight, reduced head size, and increased risk for behavioural and learning problems in childhood ○ Hard drugs are not consistently associated with IDs  FASD → low intellectual functioning, learning disabilities, hyperactivity, slow physical growth, craniofacial anomalies, cardiac problems ○ Spectrum disorder → symptoms range from mild to severe depending on the mother’s alcohol use during gestation ○ Prevalence approx. 1-3 /1,000 live births. Among children of women who abuse alochol, ⅓. ○ Can occur from only 2-3 oz of alcohol per day of gestation. Some disagreement. Binge drinking increases the chances of FASD ○ Occasional drinking may lead to subtle abnormalities ○ Most children with FASD show mild to moderate ID, although IQ scores may be borderline to low-average range. Academic problems are common, children may drop out of school. Many have learning disabilities. ADHD symptoms are the most common ○ Children are at risk for conduct disorder and mood problems as they get older. May have peer problems or be bullied How Can Perinatal or Postnatal Problems Cause Intellectual Disability? Complications with Pregnancy and Delivery Maternal hypertension or uncontrolled diabetes, delivery complications that cause anoxia leading to CNS damage are all associated with ID Premature birth and/or low birth weight → one of the greatest predictors of cognitive problems in children. Children born before 36 weeks are at risk for deficits in intellectual and adaptive functioning in infancy-early childhood ○ Motor, language, social, and/or daily living delays ○ Big risk factor because of the rapid growth of the CNS during the third trimester Childhood Illness or Injury Encephalitis and meningitis → most associated with ID ○ Both can be caused by bacterial or viral infections, viral ones more resistant to treatment Encephalitis → swelling of brain tissue Meningitis → inflammation of the meninges Serious head injuries have the potential to cause IDs ○ Drowning, force, physical abuse, etc  Physical maltreatment → shaken baby syndrome is a risk factor for cognitive impairment and ID ○ Symptoms can be irritability, lethargy, poor appetite, vomiting, tremors, death What Causes Cultural-Familial Intellectual Disability? Results from the interaction of the child’s genes and environmental experiences over time Poor acces to health care, inadequate nutrition, lack of cognitive stimulation during early childhood, low-quality education, general lack of cultural experiences during early childhood More prevalent among children from low income families. Correlation between SES and child intelligence is 0.33. Increases in severe poverty or disadvantage Low income parents tend to have lower-IQ scores, which is inherited by the children Low income children are more likely to experience gestational and birth complications, have limited access to high-quality health care and nutrition, have greater exposure to environmental toxins, receive less cognitive stimulation, and attend less optimal schools Children living in poverty showed an 8-10% reduction in brain size on MRIs ○ Greatest reductions in areas for problem-solving and memory (hippocampus and frontal lobe) How do Professionals Screen for Developmental Disabilities? Routine blood tests to screen for PKU and other metabolic disorders. Pku → a genetic counselor and nutritionist will confer ○ Parents at risk for having a child with ID or other delays, carriers of genetic disorders, with other children who have delays, or mothers older than 35 may be recommended to participate in screening Serum screening → 15-18 weeks gestation. “Triple screen” ○ 1) alpha-fetoprotein May be unusually low in Down Syndrome ○ 2) unconjugated estriol May be unusually low in Down syndrome ○ 3) human chorionic gonadotropin May be unusually high in Down syndrome ○ Serums are produced by the fetus’s liver and placenta  ○ High rate of false positives, usually additional testing follows if positive result Amniocentesis: more invasive screening technique, conducted during weeks 15-20 gestation. Involves removing a small amount of amniotic fluid with a need to test for abnormalities of the fetus ○ Carries a 0.5% risk of fetal death. Can be conducted before 15 weeks, but risk of fetal death increases to 1 or 2%. Chorionic villus sampling (CVS) → genetic screening technique that can be done between 8-12 weeks gestation ○ Physician takes a small amount of chorionic villi, which is tissue with the same genetic and biochemical makeup as the fetus ○ Performed only when there is great risk of fetus having a developmental disorder. Risk of misscarriage is 0.5-1.5% Ultrasound → detects structural abnormalities in a fetus that might indicate an ID ○ Pretty safe for mother and fetus ○ Down Syndrome becomes more obvious via facial features between 11-14 weeks Identify evidence-based techniques to prevent and treat developmental disabilities. Infants and Toddlers The Infant Health and Development Program (IHDP) → one of the largest programs developed to prevent the emergence of ID in at risk infants ○ staff made home visits and taught parents games and activities they could play with their infants to promote development ○ Staff helped parents address problems associated with caring for a preterm, low birth weight infant ○ Those in the intervention group were offered enrollment in a high-quality preschool program. When evaluated at 3 years, the children in the intervention group earned slightly higher IQs than those in the control group. This difference disappeared at age 5 This suggests that early intervention programs can boost IQ scores in at-risk children, but those increases are not maintained over time ○ Critics argue that early intervention programs dont prevent ID and should be discontinued. The time and money could be spent on primary prevention  ○ Advocates of the program believe the data speak to the importance of continuing educational enrichment for high-risk children beyond preschool years; if the program was longer, the children might continue to show higher IQs. Motivating families to participate in treatment is a critical goal for this program Head Start and Preschool Prevention ○ Provides comprehensive early childhood education, health, nutrition, and parent-involvement services to lower-income preschoolers and their families ○ Head start was originally just a summer program Communities are now starting to offer “universal” early childhood programs → designed for all children regardless of socioeconomic risk Early childhood interventions can increase children’s cognitive skills a lot Highest quality preschool programs are associated with the greatest increase in childrens cognitive skills These preschool programs overall arent associated with large improvements in childrens behaviour, but programs that targeted specific socio-emotional functioning were associated with modest improvement in behavioural inhibition and attention ○ Head start is associated with increases in child immunizations Benefits of preschool programs fade over time ○ Some still show long-term benefits (less likely to repeat a grade in school, less likely to be referred for special ed, more likely to graduate than boys who dont participate What Services are Available to School-Age Children? Apply learning theory to reduce challenging behaviors in youths with developmental disabilities.