Transcript Birth Defects and Their Causes

Week 1:
Theories and Processes of
Social, Physical, and
Cognitive Development
RC 525
Human Growth, Disability and Development
Review
 As a consequence of the fact that
 Disability is so broadly defined as to be, in a sense, a
meaningless construct,
 but one which nonetheless has historically been associated
with sometimes severe social consequences, and with
significant personal, educational, and vocational
implications,
 in this course we will consider the course of human growth
and development in a rehabilitation counseling context, and
attempt to understand the interaction between disability and
human growth and development across the lifespan from a
variety of perspectives, by understanding the person in the
context of interaction with multiple environments.
Key Issues and Ideas:
 1. Nature versus Nurture
 Nativist perspective:
hereditary, genetic,
biological factors are the
primary influence on
development.
 Nurturist perspective: The
environment shapes
behavior, and can modify
genetic inclinations
Nature v. Nurture: Twin Studies
 There is evidence from twin studies that there is a genetic
component to the development of specific speech and
language disorders, autism spectrum disorders, etc.
 But there is also clear evidence that an enriched, supportive,
or an adaptive environment, and early and appropriate
interventions can promote language and cognitive
development, and that a stimulus-deprived environment has
negative consequences for social and cognitive development.
 Our increased understanding of human biology has generally
confirmed rather than refuted the idea that development and
behavior result from the combined effects of environment and
biology.
Key Issues and Ideas:
 2. The method of research (How we try to answer the
question) affects the answer.
Key Issues and Ideas:
 3. Continuous and Discontinuous Development
 Recent studies have shown that development demonstrates some
stage-like properties and some consistency across domains, "either-or"
debates are increasingly regarded as misconceived.
Human Development: How do people
develop and grow?
 The development of a child, of a human, involves a series of
tremendously complicated events, each influenced by the
interaction of the individual with the social, physical,
chemical, and cultural environment.
 Genetics
 Reproduction
 Early childhood development
Genetics
 Genetics is fast becoming a topic of critical interest and
concern among disability advocates and professionals, as
increasingly complex ethical questions emerge from our
growing understanding and capacities in genetics.
 With increased capacity for early detection of genetic
conditions comes difficult questions for parents and society.
Genetics
 A. Genetic Counseling
 B. Prenatal Diagnosis
 C. Genetic testing and engineering:
Why See a Genetic Counselor?
 Individuals and families seek genetic counseling services at
various times and for different reasons. Some examples are:
 Before or during pregnancy to discuss factors that might increase
the chance for having a child with a birth defect or genetic
condition.
 During childhood to help better understand the reason a child has a
birth defect, developmental problem, poor growth or recognized
genetic condition
 During adulthood to discuss the likelihood for developing
conditions that are hereditary and typically occur later in life.
Some examples include cancer, heart disease and mental illness.
 (Source: American Board of Genetic Testing
Methods of Prenatal Diagnosis:
Amniocentesis- around 14th or 15th week of pregnancy, a sample
of amniotic fluid is withdrawn and analyzed.
Chorionic villus sampling- sample of tissue taken from the
placenta (9-14th week of pregnancy).
Tests for gender, Tay-Sachs, sickle cell anemia, Down
syndrome, muscular dystrophy and other conditions can be
analyzed.
A number of safer, noninvasive blood tests are currently being
developed and may soon render amniocentesis and chorionic
villus sampling unnecessary and obsolete.
Amniocentesis
Chorionic Villus Sampling
Genetic Testing
 Currently, more than 1000 genetic tests are available from
testing laboratories.
 In the US, no regulations are in place for evaluating the
accuracy and reliability of genetic testing. Most genetic tests
developed by laboratories are categorized as services,
which the Food and Drug Administration (FDA) does not
regulate.
 Only a few states have established some regulatory
guidelines.
 (Human Genome Project Information, 2009:
http://www.ornl.gov/sci/techresources/Human_Genome/medicin
e/genetest.shtml)
Genetics and Eugenics
• “Although it may border on stating the obvious, I want to suggest
that eugenic practices are widespread in our culture. Earlier this
year, for example, we had the news that prenatal genetic diagnosis
(PGD) was used to select an embryo without the gene for early
onset Alzheimer’s, resulting in a disease-free baby born to a
woman who has a gene for a specific form of Alzheimer’s, thus
sparing the baby the fate of the mother. Similarly, Britain’s Human
Fertilisation and Embryology Authority (HFEA) found itself
considering whether to allow parental use of PGD in order to
select out a pre-implantation embryo free of thalassaemia, a rare
genetic blood disorder”
• Holland, S. (2002) Selecting against difference: assisted
reproduction, disability and regulation. Presented at the Florida
State University College of Law Conference on Genetics and
Disability in March, 2002
Bio ethics
Bio ethics
 Gregor Wolbring: I am a social Entrepreneur a social-Preneur. I am a
thalidomider and a wheelchair user. I am a biochemist and a bioethicist. I
am a scientist and an activist. I work on issues related to bioethics, health
research, disabled and other marginalized people's and human rights,
governance of science and technology and evaluation of new and emerging
technologies. I am the founder of the International Centre for Bioethics,
Culture and Disability and of the International Network on Bioethics and
Disability.
 http://www.bioethicsanddisability.org/start.html
 Nonotechnology survey:
https://www.surveymonkey.com/s.aspx?sm=4RaG57PVp8ZM7w
uX3uxBYA_3d_3d
Reproduction
 The development of a child, of a human, involves a
series of tremendously complicated events, each
influenced by the interaction of the individual with the
social, physical, chemical, and cultural environment.
Assisted Reproductive
Technology
In-vitro fertilization- fertilization outside the body
 GIFT (gamete intrafallopian transfer)- egg and sperm
placed in fallopian tube
 ZIFT (zygote intrafallopian transfer)- laboratory fertilized
embryo placed in fallopian tube
 ICSI (intracytoplasmic sperm injction)- sperm injected
directly into an egg
 Future Assisted Reproductive Technologies:
ectogenesis, cryopreservation, cytoplasm transfer,
cloning
Brain and Embryonic
Development
 Within 1 week of fertilization, the growing group of cells
(splitting and forming every 10-12 hours), now termed a
blastocyst, is roughly 100 cells and has migrated from the
fallopian tube to the uterus
Blastocyst
Stem Cells
The undifferentiated cells of the blastocyst, through a variety of
genetic and chemical processes, hormonal cues, and
intracelleular communications, become increasingly
differentiated, or specialized (there are over 200 different types
of cells in the human body).
Stem Cells
At this undifferentiated stage, the cells have the capacity to
become any type of cell. These “stem cells” have a number
of important characteristics:
-they are capable of dividing and renewing themselves
over a long period of time (unlike, e.g., muscle cells, or
nerve cells);
-and they are unspecialized so can give rise to specialized
cell types.
-(Stem Cell Basics . National Institutes of Health, U.S. Department of
Health and Human Services, 2009 Available at
http://stemcells.nih.gov/info/basics/defaultpage)
Neural Development
Neural Development
 During embryogenesis (the process by which an
embryo is converted from a fertilized cell to a fullterm fetus), brain cells develop at the rate of over
250,000 per minute. There are several points during
the process of neurogenesis (the production of brain
cells) where over 50,000 brain cells are formed every
second.
 Later, neural pruning of these large numbers of cells
occurs. During the third trimester, only fifty percent of
those cells remain alive. 100 billion neurons are
retained.
Brain Development
Synaptogenesis
 Billions of synapses are
created in-utero during the
process of synaptogenesis, a
process by which the
functional circuits in the brain
are organized.
 A toddler's brain has twice
as many connections among
its 100 billion neurons (the
network communicators in
the cerebral cortex) as the
brain of a fully matured adult.
Brain Development
A fine-tuning of a child’s emerging
talents occurs between three and six
years of age. At approximately age
five or six, the brain has reached 9095% of its adult volume and is four
times its birth size. Ages three to six
are the years during which extensive
internal re-wiring takes place in the
frontal lobes, the cortical regions
involved in organizing actions,
planning activities and focusing
attention.
Early Environment
 The development of the child during the first three
years after birth is unequaled in intensity and
importance by any period that precedes or follows in
the whole life of the child
 (Maria Montessori)
Plasticity
 The brain constantly modifies the connections among
its cells that are consistently impacted by incidents
processed consciously and unconsciously by the
brain.
 When new learning occurs, there is a
neurophysiological correlate that is created to
represent one’s newly attained knowledge.
 The unfolding events that one encounters largely
determine how much cortical growth will take place,
and in what regions that growth will take place
Plasticity
 The very architecture of each human brain is altered
as a result of all newly acquired skills and
competencies.
 By the process of neural plasticity (the brain’s
ability to undergo physical, chemical, and structural
changes as it responds to experiences and to one’s
environment) the number and density of these
functional neural pathways will be determined by
the learning experiences encountered.
The Human Brain
Birth Defects and Their Causes
 Birth defects are grouped into three major categories: 1)
structural/metabolic; 2) congenital infections; and 3) other
conditions.
 Birth defects of the heart and circulatory system affect more
infants than any other type of birth defect.
 Of all infants born each year, approximately 1 in 115 has
heart and/or circulatory defects.
Birth Statistics
Birth Defects
Estimated Incidence
Structural/Metabolic
Heart and circulation
1 in 115 births
Muscles and skeleton
1 in 130 births
Club foot
1 in 735 births
Cleft lip/palate
1 in 930 births
Genital and urinary tract
1 in 135 births
Nervous system and eye
1 in 235 births
Anencephaly
1 in 8,000 births
Spina bifida
1 in 2,000 births
Chromosomal syndromes
1 in 600 births
Down syndrome (Trisomy 21)
1 in 900 births
Respiratory tract
1 in 900 births
Metabolic disorders
1 in 3,500 births
Congenital HIV infection
1 in 2,700 births
Fetal alcohol syndrome
1 in 1,000 births
Source: March of Dimes (2009). From: http://www.marchofdimes.com/aboutus/680_2164.asp
Causes
 About 10 percent of problems seen at birth can be traced to a
specific agent (environmental agent, drug, biologic, or
nutritional factor). About 20 percent are inherited or are
associated with chromosomal changes. The rest (about 60%)
are of unknown etiology
Teratogens
 To be classified as a teratogen, a chemical must cause
significant structural or functional abnormalities in the
developing fetus after either direct exposure or exposure to
the pregnant mother.
 Periods of time in which a teratogen can have a negative
effect on a developing fetus can be divided into either critical
or sensitive periods.
Human Developmental Theories
 Childhood is a culturally defined
concept
 In the relatively new idea of
childhood, ideas have fluxed
between child-as-little-adult and
child as developmentally pre-adult,
still in development.
 Even today, with globalization,
there are still marked cultural
differences in the concept of
childhood.
Psychoanalytic Model
 Key ideas introduced by Freud:
 1. The importance of the developmental period (birth to
6 years) on later personality
 2. The concept of stages of development and
developmental tasks that must be mastered before
advancing to the next stage
 3. Developed ideas that were, for better or worse,
maintained for decades in Western psychology
Development
 Five stages, each dominated by the development of
sensitivity in a particular erogenous or pleasure-giving
zone of the body
 Each stage presents a unique conflict that must be
resolved before passing on to the next stage.
 Unsuccessful resolution of the conflict leads to
fixation—the tendency to stay at a particular stage
Oral Stage
 Oral stage – birth to 2
 Focus- Mouth, digestive tract
 Issue- need for food- basic nurturance, and pleasure-What is selfpreserving and sexual (as defined by Freud) is pleasurable
 Resolution - develop trust that the world will fulfill needs and one
can be satisfied.
 Oral Fixations:
 -Oral receptive - dependent, gullible (swallow anything) want to
have things- attain info, knowledge, goods- oral fixation
 -Oral aggressive - conversationally aggressive, sarcastic,
possesive of others
Anal Stage 2-3 yrs
 Focus:
Satisfaction - tension released through BM
 Issue-
Self- Control over Bowels & Toilet training
 Parental control & Power- Reactions of parents at this
stage affect personal view- eg, supportive and
encouraging = self esteem
 Fixation Anal retentive- stingy, saving, orderly
 Anal Expulsive- messy, sloppy, reactionary, tantrums and
outbursts
Phallic Stage 4-5 years
 Focus- Satisfaction through genital stimulation
 Awareness at this stage of presence or absence of
penis
 Oedipal complex (boy wants to possess mother and
father is rival)
 Electra Complex (girl wants to possess father, mother is
rival)
 Castration Anxiety and Penis Envy develop
And the rest
 Latency Stage 6-12
 Decreased, or repression of, sexual interest- energies
are redirected to more personally and culturally
acceptable objects
 Genital Stage- 12-maturity
 Sexual energy is invested in friendship, leisure, career
development
Psychosexual Stages
 Criticisms:
 1. Few predictions can be tested using the scientific
method.
 2. Based on the biases of the male-dominated culture
of the Victorian era
 3. Not based on observation or work with children, but
retrospective of Freud's patients who had emotional
difficulties
Erik Erikson: Psychosocial
Stages of Development
 Eight stages, each of which confronts the individual
with a major conflict that must be successfully resolved
if healthy development is to occur
 Development follows the epigenetic principle.
 Unlike Freud, Erikson emphasizes that the continual
process of personality development takes place
throughout a person's life span.
Erik Erikson 1902-1994
 Conflict and tension are
sources of growth,
strength, and
commitment
 Joan and Erik Erikson,
1997
Psychosocial Stages
 Oral sensory- Birth to 1
 Trust v. Distrust
Psychosocial Stages
 Muscular-Anal- Early childhood (2-3 years)
 Autonomy v. Shame & Doubt
 Locomotor-Genital- (4-5 years)
 Initiative v. guilt
Psychosocial Stages
 Latency
(6-11 years)
 Industry v. Inferiority
 Puberty and adolescence (12-18)
 Identity v. Role Confusion
 Young adulthood :
 intimacy v. isolation
Psychosocial Stages
 Adulthood
 Generativity v. Stagnation
 Maturity
 Ego integrity v. despair
Behavioral Models
 Common Assumptions:
 Development is a function of learning:
 Reinforcement, punishment, organization of learning
determine and influence development
 Individual differences reflect different learning histories
and experiences
 Development results from the organization of learned
behaviors; Development progresses from simple
behavioral responses to more complex behaviors, but all
are subject to the laws of learning
Behavioral Models
 Observable Behavior and not mental processes should
be the focus of psychology
 Person as product and producer of her environment
 Biological factors set general limits the kinds of
behavior that develops, but the environment
determines the kinds of behaviors in which the
individual engages
 Environment and biology interact, but environment is
the key to observed behaviors
Behavioral Models
 J.B Watson - Classical Conditioning
 S-R
 All behavior can be understood as a result of
learning
 Give me a dozen healthy infants, well-formed, and my own
specified world to bring them up and I'll guarantee to take any
one at random and train him to become any type of specialist I
might select--doctor, lawyer, merchant-chief, and yes, even
beggarman and thief, regardless of his talents, penchants,
tendencies, abilities, vocations, and race of his ancestors."
(1930)
Little Albert
B.F. Skinner
 Operant Conditioning Behavior is a function of its consequences
(positive/negative)
 Positive = Reinforcement
 Negative-punishment = Extinction
 Meaningful reinforcers
 Primary- Inherently rewarding
 Secondary- Reward derived through
learning
Piaget
 Pioneer in raising awareness of the idea that children
think differently from adults
 Child is an active agent in development
 Conflict produces growth and development
 Children progress through distinct but interrelated
stages of cognitive development
Piaget’s concepts
 Schema: in interaction with environment, children form
cognitive structures for dealing with the environment;
ways of understanding the world
 Assimilation: Taking in new knowledge and information
and interpreting so as to fit in the the existing schema;
existing view of world
 Children generally stretch schema as far as possible to fit
new observations
Piaget’s concepts
 Disequilibrium: Observations no longer fit within the
existing schema
 Accommodation: Evolution of a new schema to fit new
understanding of world
Piaget’s Stages
 Sensorimotor- Birth to 2
 Increasing awareness of sensory-motor integration
 Object permanence
 Cause and effect
 Pre-operatonal- 2-7
 Capacity to use symbols to portray external world
internally (especially language)
 Egocentrism- Child’s own point of view is only point of
view
Piaget’s Stages
 Concrete operations- 7-11
 Mastery of logical operations, math, hierarchical structures,
quantity and shape
 Rule-based
 Formal operations- 11 and over
 Capacity for abstract thinking
 Scientific thought
 http://www.youtube.com/watch?v=fcjPkPIwsog
 http://www.youtube.com/watch?v=ue8yJVhjS0&feature=PlayList&p=D040BA09E49C1E63&index=0
&playnext=1