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Early Brain Development and Its Implications for Working with Young Children with Sensory Loss

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Title: Early Brain Development and Its Implications for Working with Young Children with Sensory Loss


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Early Brain Development and Its Implications for
Working with Young Children with Sensory Loss
Linda AlsopSKI-HI InstituteUtah State University
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Early experiences are so powerful that they can
completely change the way a person turns
out. Harry ChuganiPediatric NeurobiologistWayn
e State University
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Genes might determine only the brains main
circuits, with something else shaping the
trillions of finer connections. That something
else is the environment,
the myriad messages that the
brain receives from the outside
world. Sharon Begley
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A persons ability to interact, perceive, and
learn from the environment comes from the ability
to process incoming sensory information and react
to the information with a motor response which,
in turn, feeds back sensory information.
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The central nervous system consists of the brain
and the spinal cord.
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The Brain
  • The brain has two basic functions
  • The first function of the brain is to
    communicate.

The brain communicates by receiving sensory
information from the environment via the eyes,
ears, nose, mouth, position in space, and nerve
endings throughout our body. This information is
then sent to other parts of the body via the
spinal cord and the peripheral nervous system.
Subsequently, the central nervous system (CNS)
receives signals from the rest of the body and
then plans and sends signals back to the
environment. Such response signals may be
intentional (e.g., talking, writing, signing) or
unintentional (e.g., flushing, startling,
breathing heavily).
  • The second function of the brain is to
    integrate incoming sensory information with
    information already stored in the brains
    subconscious and conscious memory banks.

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  • The brain is made up of about two hundred
    billion interconnected neurons or nerve
    cells. A typical nerve cell has a cell body
    which is attached to one major fiber or axon
    with a number of fibrous branches called
    dendrites. Dendrites receive messages coming
    into the neurons which, in turn, combine and
    integrate the signals. The neurons then emit
    outgoing signals via the axons. These
    neurons communicate with each other via chemical
    secretions called neurotransmitters.
  • The more the brain engages in problem-solving
    activities, the more it developsnot through
    gaining new neurons but through dendritic
    branching.

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  • Most of us are born with more neurons than we
    need, which is good because some die off even
    when there is no insult to the brain.
    Individuals who have suffered from severe
    neurological insult have had significantly
    more neurons killed off than would occur
    under typical conditions. Once a neuron is
    damaged or dies, it cannot be revived
    however, appropriate habilitation or
    rehabilitation services may assist in
    promoting the dendrites of remaining neurons
    to branch out more.

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The Brain and Sensory Input
  • The first priority of the brain is to keep us
    alive.
  • The second priority of the brain is to enable
    us to deal with our body and its interaction
    with the world it senses around us.
    Genetically, we are imprinted to survive.
  • Humans are constantly bombarded with
    stimulienvironmental information about
    ones own body, light, noise, temperature, etc.
  • The entire CNS needs sensory input, but the
    input must be meaningful to the brain in
    order for it to be helpful. A confused
    brain will do what it can to make sense of what
    it is experiencing.

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What Happens When the Brain Receives Messages?
Corpus Callosum The brain is divided from front
to back into two hemispheres joined together by
fibrous tissues called the corpus callosum. It
is responsible for passing messages from one side
of the brain to the other.
Sensory Systems All the information we receive
comes through one or more of oursensory
systemseyes, ears, nose, mouth, position in
space, andnerve endings throughout the
body. Reticular Activating SystemThe incoming
sensory information alerts the reticular
activating system (RAS) to be prepared to
receive and transmit messages. The RAS has to be
aroused to perform its functions.
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  • Anesthesia, some drugs, and deep sleep
    affect the reticular activating system, so
    there is no conscious processing of the
    incoming stimuli even though the information
    has been received and transmitted by the
    sensory avenue(s).

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Thalamus
  • The thalamus is a small brain structure that
    plays a major role in determining which
    sensory information is going to receive the most
    conscious awareness.
  • All incoming sensory information, except for
    smell, is sorted by importance.
  • Information that has been encountered
    previously, and found to be harmless, may be
    ignored. New information will require more
    attention until it proves not to be a threat
    and/or not requiring active attention.
  • If the incoming information contradicts
    existing information, the rest of the brain
    will be alerted to pay attention to this new
    information.
  • The thalamus helps the rest of the brain to
    know what is important to attend to and what
    is not important to attend to.

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  • The thalamus is especially vulnerable to
    insult that may have occurred in early life,
    especially if there was a lack of oxygen
    (anoxia).
  • The thalamus, like the RAS, is highly
    affected by medication.

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Limbic System
  • The limbic system evaluates incoming sensory
    information. It is the brain structures
    responsible for emotions.
  • The limbic system evaluates in two primary ways

1) The limbic system finds familiarity
comfortable. Novel experiences increase
discomfort, which results in stress. The limbic
system subconsciously assesses information
on a comfort continuum. 2) The limbic system is
the subconscious emotional system that
provides subconscious level perceptions. If the
limbic system perceives a situation as
threatening, a fight or flight response
kicks in and the limbic system sends warning
signals to the basic power plant
(hypothalamus). In turn, the hypothalamus sends
out other hormonal signals to prepare for
battle.
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  • The brain is programmed to maintain
    equilibrium.

When the brain is faced with a new experience, it
subconsciously/ subcortically and/or
consciously/cortically evaluates the experience.
If the experience is understood in the light of
previous experiences remembered by the brain, it
gets a little excited. Small to moderate amounts
of excitement/stress are alerting. (Novelty
new experience as perceived by the brain.) If
however, the experience runs counter to what the
brain already knows, then it perceives the
situation as potentially threatening, and it
prepares to defend itself. Too much stress tips
the scale the wrong way and is dangerous for
anyone. Stress is the reaction of the body to
changes in the status quo. When an individual
gets angry or frightened, the body mobilizes
resources with a primitive response known as
flight or fight. When this situation occurs,
the body automatically releases stress hormones.
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Stress Hormones
Stress hormones have wide-ranging effects on the
body. They are released into the body when the
brain receives the signal that danger is
near. One of these stress hormones is cortisol.
Cortisol gets glucose (energy) into our bodies
and also helps rev up the sympathetic nervous
system (heart rate), increase our vigilance and
attention to threat, and decrease our attention
for other things. Once you get this stress
response going, you have to be able to turn it
off. Here is where the hippocampus comes in. This
is really important because chronic stress with
too high cortisol levels decreases memory and the
ability to control behavior and focus attention.
It also slows the immune system.
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  • Indiscriminate sensory bombardment, as an
    educational practice, is not justifiable with
    those individuals who have significant
    neurological insults.
  • If the brain receives too much information
    and receives it too quickly, it cannot
    understand, and a state of stress will
    occur. The results may well be
    individuals who become more ill than they
    need to be.

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  • Sensory Disorganization and Emotional
    Development Difficulty in processing and
    understanding sensory informationnew
    environments, materials, activities, and
    motor patternscreates a reluctance to
    attempt new adventures. Situations which
    exacerbate sensory disorganization can be
    scary.

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  • Every experience needs to be examined from the
    childs perspective. If stress is at a high
    level for prolonged periods of time, then the
    bodys physiological defenses may be working
    overtime.
  • If the stress is unrelenting, from the brains
    perspective, then the immune system will be
    affected, and the child may become ill more
    frequently and/or more seriously.
  • Messages received by the olfactory system
    (smells) are directly processed by the limbic
    system. Thus, smells evoke memories and
    strong emotions.

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Amygdala and Hippocampus
  • The amygdala and hippocampus are part of the
    limbic system. They are critical in the role
    of memory, in anticipation, and
    habituation.
  • These two structures and others process
    events for storage in the subconscious memory
    bank.

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Stress and constant threats rewire emotion
circuits. These circuits are centered on the
amygdala, a little almond-shaped structure deep
in the brain whose job is to scan incoming sights
and sounds for emotional content. Impulses from
eye and ear reach the amygdala before they get to
the rational, thoughtful neocortex. If a sight,
sound or experience has proved painful
beforethen the amygdala floods the circuits with
neurochemicals before the higher brain knows
whats happening. The brain remains on high
alert. In this state, more circuits attend to
nonverbal cuesfacial expressions, angry
noisesthat warn of impending danger. The cortex
falls behind in development and has trouble
assimilating complex information such as
language.
Sharon Begley
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  • The hippocampus and amygdala are highly
    effected by anoxia at birth and are very
    susceptible to seizures.
  • It is critical to use techniques that will
    assist the child in perceiving the routine of
    individual activities. It is important to
    make the situations predictable, interesting,
    and challenging but not overly stressful.

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Hypothalamus
  • The hypothalamus is the involuntary center for
    controlling heart rate, temperature,
    constriction/dilation of blood vessels, water
    balance, hormone secretion, appetite, etc.all
    functions that maintain physiological
    equilibrium and life.
  • The hypothalamus and limbic system
    constantly influence each other.
  • The observable manifestations of
    hypothalamic functioning are a critical clue
    regarding the childs state of arousal,
    degree of stress, and readiness for learning.

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bronchial tubes open for deeper breathing
heart beats faster, contracts strongly
hair shaft may become erect
eyes dilate for more focused vision
EXTREME STRESS ACTIVATES POWERFUL INTERPLAY OF
LIMBIC SYSTEM AND HYPOTHALAMUS
digestion slows down
blood sugars increase for energy
blood pressure rises
muscles contract and blood vessels widen to
accommodate increased oxygen needs
other vital organs aroused
surface vessels of skin contract
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  • Many children who have significant neurological
    challenges may never talk, use sign, write, be
    effective with technology, or, in extreme
    situations, use any form of intentional
    communication.
  • These other indices are subcortical,
    physiological indicators. These
    unintentional reactions are manifested by
    such behaviors as posture, tone,
    respiration, flushing, palloring, and so
    forth.

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Learning
  • Learning occurs on two levels sub-cortical and
    cortical.
  • Learning includes the development of orienting,
    anticipating, and habituating responses
    which, in turn, rests on the ability to
    discriminate, associate, and remember
    sub-cortically and/or cortically.

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Orienting
  • To orient is to be aware that an event is
    occurring. This is a very early indicator of
    cognitionthe individual recognizes that there
    is a new stimulus and does something of an
    autonomic nature to indicate that recognition.
  • To orient to a stimulus involves the ability
    to neurologically be prepared to
    receive, organize, and interpret
    incoming sensory information at some level
  • inhibit some information via the
    thalamus and
  • re-alert when there is an introduction of a
    new experience (novelty).

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  • Children with severe neurological challenges
    may orient, but have great difficulty
    recognizing and remembering a routine. Many of
    these children will demonstrate the same
    level of arousal each time the same stimulus
    is present, and this level of arousal may not
    lower. These children may not be learning
    they may just orient to the stimulus and be
    aroused. The stimulus, under these situations,
    does not lose its novelty.

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Anticipating
  • Anticipation is a higher level of subcortical
    neurological functioning critical to the learning
    process. Anticipation is the ability to guess,
    within a system of predictability, what the next
    event will be. Anticipation requires attentional
    processing and the ability to remember an event
    or a sequence of events.

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Habituating
  • The systems of the brain regulate a process
    called habituation, a process in which a
    response to a stimulus becomes automatic.
  • The child learns to recognize a
    stimulus that has been given repeatedly
    to respond to it in an automatic manner.
  • This is the most basic process of learning.
    It involves sensory receptivity, sensory
    awareness, attention, discrimination, and
    memory.
  • The ability to learn requires the ability to
    habituate. Habituation is the process by
    which the brain gradually adapts to a new event
    or sensation and no longer consciously
    notices it, because the event or sensation
    has been integrated with other information and
    experiences.

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  • In teaching situations, there is a critical
    need to carefully monitor and control the
    sensory-motor demands of each event and each
    material within each activity in order to
    maximize participation and minimize startling,
    fatiguing, and/or stressing.
  • Memory can be enhanced by setting up a
    sequence of very routinized activities
  • presenting sequenced activities in a
    very routinized manner and
  • careful monitoring of and responding
    to communicative physiological, visual,
    and motor cues.

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Attachment
  • Attachment develops from an environment that is
    predictable and people who are responsive to
    the cues the child provides. If people and life
    are confusing and nonresponsive, then people
    and objects cannot be trusted.
  • A critical area that frequently is affected by
    significant neurological insult is
    attachment. Attachment to a primary or
    significant person ties in with conditioning
    and learning.

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Educators can take the principles of normal
learning and systematize them to promote the
learning of individuals who are deafblind and/or
have multiple disabilities by 1. Aiding the
child in discriminating one adult from
another2. Establishing routines feelings of
security and reduction of stress come from
being able to anticipate what is going to
happen. We can only anticipate when we
perceive some pattern and remember it
and3. Systematic and salient association of
certain objects with certain events.
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  • The neurological approach, when viewed from an
    educational perspective, is concerned with the
    childs
  • strategies in receiving and processing sensory
    information
  • capacities in managing increasingly more
    complex sensory- motor demands
  • discrimination, memory, and association
    abilities
  • states of arousal
  • behavioral organization
  • level of stress
  • attending behaviors
  • anticipatory behaviors
  • motivation
  • stereotypic and self-abusive behaviors and
  • physiological and motor communicative signals.

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Working with Children who have Experienced
Significant Neurological Insults
1) The childs reactions and responses may be
extremely variable not just day to day
but also moment to moment. 2) Energy levels may
be extremely variable. 3) The childs attention
may vary widely depending on difficulties
encountered in managing the sensory/motor demands
of the task and preference for the
activity and/or individual. Sustained attention
is a derivative of sustained motivation.
Start activities with what the child
knows. Gradually introduce novelty in small
increments. 4) Motor limitations make it
difficult to plan and execute motor
responses in a timely manner.
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5) Rate and timing of responses by the child may
be frequently delayed. Others may step in
before the child has had time to process
the incoming stimuli, plan and execute a
response. The responses of others may be
misunderstood by the child. 6) Individuals who
have a hard time managing information from the
environment may become anxious, stereotypic in
their behaviors, and internalized. 7) Health
may be affected by stress. 8) Reading
communicative signals of a child who has
significant neurological dysfunctioning is
difficult. It is important to listen to the
physiological and motor cues of the
child. 9) Consider the sensory environment. Some
environments may be overly aggressive from
the childs perspective.
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10) Multi-sensory experiences may not be the best
teaching route. Introduce one
sensory-modality at a time, and build
slowly. 11) Consistency and predictability are
critical. The introduction of
appropriate new (novel) experiences is
also critical. 12) Slow down. Pace the
interactions.
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  • References
  • Understanding Deafblindness Issues,
    Perspectives, and Strategies L. Alsop (Ed.),
    SKI-HI Institute, Logan, UT, 2002.
  • Communicating Research to Practice and
    Practice to Research From theoretical
    contributions to therapeutic interventions. Jude
    Nicholas, Resource Center for the Deafblind,
    Norway.

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