Trish Lowe NE 2013

Eszter Jozsa CNE 2019

The problem with prematurityPrematurity introduces the developing infant into a hostile

environment full of excessive noise

bright lights

painful procedures

excessive handling

The neurological system needs to cope with complex interventions

Our role is to support the developing infant’s brain, to protect sleep and facilitate the establishment of effective sleep cycles

This gives rise to, orderly sensory development, laying down of memory circuits and preservation of brain plasticity.

Preterm birth leads to

Maturation of the lungs, kidneys and gastrointestinal tract

It does not accelerate neurodevelopment, in

fact, it can severely interfere with it

Brain development is impacted by two factors:

• Genetic direction

• Relates to genetic predisposition, combined with, epigenetics

Environment

noise

bright lights

sleep deprivation

poorly timed care provision

physical, nutritional and social/emotional environment

Neonatal brain development

Three distinctive layers exist1 EMERGENCY - Brainstem

The primitive or reptilian brain. No cognitive activity. Responsible for reflexive, instinctive behaviour, such as self preservation.

2 EMOTIONAL - Limbic systemControls emotions by releasing hormones, which enable anger, fear, rage , happiness. Also processes smell and taste, which have powerful connections to our emotions.

3 EXECUTIVE - Cerebral cortexThe “thinking brain”. Organises complex sensory intake. Responsible for detailed processing, which enables thinking, remembering, planning, reasoning, understanding and communicating language.

Brainstem

Brainstem Medulla, cerebellum, pons

First fashioned at approximately 30th day of gestation

Completely developed and myelinated by 28 weeks gestation.

Processes vestibular sensations responsible for hearing, balance, vision, focussing and regulates autonomic functions, such as breathing, heart rate.

The following months primitive reflexes, like stepping, moro, are controlled increasingly by cerebral cortex, consequently disappear and are suppressed.

Limbic system

Limbic system

Centrally located within the brain

Basal ganglia -relays vestibular messages, from the inner ear, the cerebellum, and the cerebral cortex.

Hippocampus -compares and moderates responses to stimuli attached to memory.

Amygdala -connects impulses from the olfactory system and the cerebral cortex, processes memory and emotional reactions.

Hypothalamus -controls autonomic nervous system responses, such as temperature, hunger, thirst and emotive responses, such as anger and pleasure.

Cerebrum

Cerebrum Cerebral cortex -also known as cerebrum or

neocortex-“grey matter”, ensures complex control and organisation of sensory input and voluntary body functions. The surface area is expanded by grooves and fissures called gyri and sulci.

2-4mm thick Left and right hemispheres Left hemisphere- cognitive analytical functions Right hemisphere- sensory, intuitive functions

such as, emotions and art appreciation Corpus Callosum – hemispheres connected by

nerve fibres, which conduct and integrate responses between hemispheres.

Sleep and brain developmentSleep cycles were first described in the 1950’s

‘Sleep deprivation in the fetus and young infant has a profound effect on the early sensory development and creation of permanent neural circuits’ (Graven and Browne, 2008: 173)

Essential for:

Sensory system development

Preservation of brain plasticity

Creation of long term memory

and learning

Development of sleep cycles

20-28 weeks -irregular electrical activity, characteristic of the immature brain.

Periods of rest interspersed with periods of activity.

Intermittent nerve cell electrical activity, which is required for nerve fibre growth targeting and connection building.

Development of sleep cycles At 28 weeks -distinct electrical patterns, differentiating

sleep states emerge with continuous EEG patterns apparent by 36-38 weeks gestation.

Non-REM or slow wave sleep Stages 1-4 - drowsy , light, deep, slow sleep

High amplitude, synchronised, slow wave EEG pattern, very little muscle movement, regular HR and RR

REM or paradoxical sleep Rapid eye movement and muscle movement

In the fetus and neonate is a period of maximal brain activity

Critical component of the deep sleep cycle associated with development of sensory systems.

REM versus Non-REM 28-30 weeks - mostly REM with very little NREM

40 weeks - 50% REM and 50% NREM

8-9 months of age - 20% REM and 80% NREM

Sleep and sleep cycles are not passive processes

Controlled by aminergic and cholinergic cells and associated neurotransmitters, like serotonin and acetylcholine

Preservation of brain plasticity

Brain plasticity is defined as, ‘the preservation of the capacity to change, adapt and learn in response to environmental experiences and new needs’(Graven and Browne 2008: 174)

Preservation of brain plasticity, requires activation of key cellular components like nerve growth factor, brain-derived neurotropic factor and ubiquitin) which commence in response to REM sleep during fetallife and depend upon sleep cycles, for ongoing maintenance, during the lifetime of the individual.

Learning and memory Learning and long term memories are created during

distinct phases.

Acquisition phase - creates short term memory circuits by undertaking an activity. May last longer if actions are reinforced or repeated.

Consolidation -is required to become long term memories.

0-wave oscillations - transfer short-term memories into the hippocampus sorting files and establishes permanent connections.

occurs during periods of Non-REM sleep

Supporting sleep in the NICU Sleep organisation is directly related to developmental

outcomes.

It is essential to time interactions and interventions appropriately during arousal periods and avoiding sleep periods.

Behavioural identification of transition between arousal states can guide care provision.

Preterm and compromised infants cannot consistently organise their behaviour to maintain sleep and wake states.

They are sensitive to the caregiving environment .

Intrusive care giving results in negative facial expressions and altered sleep-wake transitions.

Evidence based practices can assist Positioning - swaddling, rest periods, non-nutritive sucking Individualised cue-based care - avoidance of clustered care, as this is

associated with hyper arousal and poor heart rate modulation Familiarisation with infant states Kangaroo care - increases sleep time and sleep-wake cyclicity,

supports physiologic and behavioural organisation and promotes attachment

Day/Night lighting - to promote circadian rhythms-recommended low/day - low enough for the infant to be able to comfortably open their eyes when interactingdim/night - crib covers down during the night and up during the day, never exposing infants eyes to direct, bright light, at any gestational age.

Encourage mother to be present and provide breast milk. Breast milk composition includes melatonin, which supports establishment of circadian rhythms

Sensory development

Sensory systems develop in sequence:

1. touch develops first

2. vestibular (proprioception)

3. olfactory (smell)

4. gustatory (taste)

5. auditory (hearing)

6. importantly, vision is last

Crucial for development of neural “architecture”

Altered sequencing results in interference, altered development, poor coordination with other systems and subsequent sub-optimal function.

The impact of preterm birth on sensory development Structural growth of eyes, ears, olfactory bulb and

receptors for touch, position and motion develop during early gestation and are innervated between 22-40 weeks gestation and 3-5 months of neonatal life.

Preterm birth does not accelerate development of brain function or early sensory development but can be interfered with when exposed to stimuli which are intense, unusual or out of character.

Therefore, the physical, sensory and social environment is crucial in order to support appropriate development.

Noxious influences on the developing neonate high pitched sounds

bright lights

pain

frequent exposure to stress and stress hormones

less exposure to calming hormones (e.g. maternal oxytocin)

The development of the brain is dependent upon:

genetic endowment

internal or endogenous stimulation

sleep

external experiences and stimulation of sensory organs

the environment (physical, chemical, sensory and social/emotional)

Genetic endowment Brain architecture, cell differentiation, cell migration,

primary or initial cell location, response to stimulation are directed by genes and genetic endowment.

Expression of genes is impacted by environment and outside stimulation.

Timing, intensity and type of stimulation, modifies gene expression. Brain development occurs as a result of genes (nature) experience and use (nurture).

Epigenetics-the study of heritable changes in gene expression or cellular phenotype caused by external mechanisms, such as those from the physical, chemical, sensory and social/emotional environment.

Internal or endogenous stimulation and sleep

Random, spontaneous, endogenous firing of sensory and motor ganglion cells is an essential process involved in axon growth and targeting.

Firing of ganglion cells becomes more regular with maturation of sensory organs.

Synchronous wave firing commences at around 28 weeks causes synapses within the sensory system forming permanent connections, circuits and architecture of sensory nuclei and neocortex. Regular firing is associated with REM sleep.

Drugs, environmental influences and lack of sleep, interfere with emotional and social development, long term memory, long term brain plasticity and future learning.

External experiences and stimulation of sensory organs

Initial stimulation of sensory systems is internal/endogenous.

At critical junctures external stimuli required.

Must be appropriate in sequence, intensity and form.

All sensory systems, except vision need external stimulation as part of development inutero (e.g fetus hearing in utero). Visual system, needs synchronous firing of retinal ganglion cells, but does not need light or vision to develop. If in doubt, consider how dark the intrauterine environment is for infants born at term.

EnvironmentElements, which effect fetal, infant and child development:

physical-space, position, movement, motor development and ability to move

chemical- nutrition, nutritional factors and toxins. Can have epigenetic effects which alter gene expression

sensory- sound, voice, touch, movement, smell, vision, protection of sleep

social/emotional- touch, smell, hearing and vision. The attachment of social and emotional characteristics to sensory stimuli, create memory circuits in the limbic system and social learning centres.

Adverse environmental effects can lead to lifelong alterations in brain development, function, (neurodevelopment and neuro-processing)

Critical periods

Each sensory system has a sequence and critical time sensitive period for appropriate stimulation, triggering and development

Events, stimuli, environmental influences can either support or interfere

Neurosensory wiring disorders, may contribute to adverse outcomes reported by high risk infants

The importance of chemosensory development Gustatory (taste) and olfactory (smell) sensory influences

have a profound effect on detection of environmental information and contribute to cognitive and emotional interpretation of daily experiences.

Associated with avoidance of harm, (e.g. caustic food or dangerous compounds)

Provide enjoyment (e.g. delicious food or perfumed aromas)

Influence relationships between parents and children through identification, protection, nurturing (e.g. odorants and pheromones)

Chemosensory development Newborns detect, discriminate and respond to odour

and taste physiologically and behaviourally

Examples-arousal, head turning, mouthing, movement towards the source

“Sensitive period”, for olfactory sensory development, occurs within first hour of life due to high circulating norepinephrine

Exposure to amniotic fluid and breast milk during this time- impacts significantly on breast feeding outcomes

Preterm infantsPreterm infants can discriminate between scents from

28 weeks.

Respond with:

physiological reactivity

oral movements

head turning

gagging

crying

behavioural activity less vigorous than in term infants

Important care considerations

Support mothers and their babies to remain together. Provide infant with the smell of mother’s amniotic fluid and

breast milk. Provide EBM as preferred mouth care and feeding, EBM dipped

pacifier, demonstrated increased non-nutritive sucking, intake, growth and reduced length of stay.

Transition the inclusion of new formulas or medications by progressively introducing them accompanied by known tastes such as EBM.

Familiar soothing odours can promote physiological stability. Offer scent cloth.

Provision of maternal odour during painful procedures assists with physiological stability, however concerns exist about negative associations between mother’s scent and pain.

Important care considerations

Avoid introducing foreign smells. Staff should not wear perfumes!

Infants exposed to strong trigeminal stimulants such as disinfectants and detergents, alcohol and caustic liquids have demonstrated, decreased oxygenated haemoglobin over the parietal region of the brain.

Be mindful of strong odours in enclosed spaces such as incubators. Humidity and warmth potentiate odours further.

Auditory development

Important for receiving, interpreting and responding sounds, especially language and music.

Anatomical and structural components develop by 15-20 weeks. Functional by 25-29 weeks.

Ganglion cells of the spiral nucleus in the cochlear connect inner hair cells to the brainstem and temporal lobe of the cortex.

In-utero, intense (>60dB) noise must be avoided after 20weeks gestation.

At 25-26weeks, loud noise will generate autonomic alterations.

Auditory development after 28 GA Appropriate development requires auditory experience

with voice, language, music and meaningful sounds from 28-30 weeks either in utero or NICU.

After 28 weeks baby needs exposure to mothers voice, family voices, music and meaningful sounds. Background noise must be kept at <50dB

In the NICU disruption to sleep must be avoided.

Learning auditory patterns requires REM sleep after 32 weeks to create long-term memory.

Demonstrate requirements for developmentally appropriate care. Control background noise, expose to appropriate auditory experiences such as parents voice.

Visual development before 32 GA

Preterm infants at less than 32 week:

Little or no pupillary constriction in

response to light

Thin eyelids

Little ability to reduce light on the retina

By 36weeks pupillary response is more reliable and the eyelids are thicker, therefore babies can begin to limit light exposure.

Visual development after 36 GA

The intrauterine environment is dark, therefore light or visual experience is not required until term.

Visual development does rely on synchronous wave formations associated with REM sleep.

In the NICU, protect eyes from direct light at all times.

Colour pathways begin to operate at 2-3 months of age. Thereafter, babies require protected sleep and regular, meaningful visual stimulation when awake.

Summary of proven interventions Recognise the vulnerability of infants born prematurely, especially

prior to 28 weeks gestation.

Further your own knowledge and educate parents on the importance of providing a supportive environment.

Protect sleep at all ages. Increase awareness of state. Deliver care at appropriate intervals.

Provide supportive touch from birth regardless of gestational age (skin-to-skin contact, positioning and containment).

Introduce familiar and positive odours within the first hour after birth.

Provided purposeful, low level auditory stimulation.

Cover eyes, protect sleep at all times and introduce appropriate visual stimulation when awake.

ReferencesBrainLife 2013. Online-Available URL: http://www.brainlife.org/reprint/2012/WP-Epigenetics_120505.pdf

<Accessed 2014, Jan, 8>

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Graven, S.N. and Browne, J.V. 2008 Sleep and Brain development. Newborn and infant nursing reviews, 8, 4, 173-178

Graven, S.N. and Browne, J.V. 2008 Auditory development in the fetus and infant. Newborn and infant nursing reviews, 8, 4, 187-193.

Graven, S.N. and Browne, J.V. 2008 Visual development in the human fetus, infant and young child.Newborn and infant nursing reviews, 8, 4, 194-201.

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