Neonatal Nervous System and Reflexes

Neonatal Nervous System

• The newborn's nervous system controls functions like hunger, thirst, and satiety, balanced by hypothalamic centers. It also influences sucking and swallowing.
• Neonates are born with active sensory pathways (smell, taste, sight, and sound), used in utero. They learn by processing and responding to sensory stimuli.
• Movements can be reflexive or volitional, under control of the motor cortex. Myelination of nerve tracts gradually leads to better motor control.
• Sensory stimulation supports skeletal muscle development and neural connections via new dendrites and interneurons.

Reflexes

• Autonomic reflexes are involuntary motor behaviors, crucial for safety and survival, often within the spinal cord.
• Assessing reflexes helps evaluate the integrity of the neurological system.
• Grasping and Moro reflexes are used to assess central nervous system development in newborns.
• Absence of reflexes may suggest brain damage, asphyxia, neurological issues, or drug exposure.
• Some primitive reflexes may reappear in adulthood, potentially due to neurological problems.

Neurological Examination

• The Apgar score assesses the baby's response to handling and tone, as well as limb movements and alertness.
• Level of consciousness (alertness and interaction) and adaptation to temperature are also assessed, along with cry tone and its clarity.
• Pain perception can differ, making accurate assessment difficult.
• Feeding responses and facial dysmorphism (facial anomalies) are examined.
• Eye movements are observed for reaction to light and ability to fixate, providing potential neurological markers.
• An anal wink assesses the strength of the anal sphincter.

Behavioural States

• Normal newborn posture involves flexion with the head centered, and alternating arm and leg movements.
• Jerky movements (startle/myoclonic jerks), when limbs are moved, are expected and normal.
• Traction response (ability to hold a seated position) is observed.

Sleep Patterns

• Normal term newborns cycle through various sleep stages (e.g., active, light, and deep sleep).
• Approximately 50 minutes of sleep is spent each hour, with roughly half of that time in quiet sleep.
• Sleep patterns are not typically tied to a light-dark cycle, although this can vary.

Key Neurological Alarm Signals

• Potential red flags include persistent irritability, feeding difficulties, asymmetrical posture and movement, floppiness, abnormal cries, setting sun eyes, convulsions, respiratory difficulties, or unusual apathy, or hyperactivity.
• These rare signals require urgent referral and investigation.

Next Steps

• Discuss any concerns with a practice supervisor and consider possible referrals as necessary.
• Communicate findings carefully with parents using a sensitive approach.
• Thorough documentation of observations is necessary.