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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