Learn about primitive reflexes like the Moro reflex, palmer and plantar grasp reflexes.
WORDS ANNA FERNANDEZ
A reflex is an involuntary and almost instantaneous response to external stimuli (sound, touch, or light). A reflex occurs involuntarily and does not require any thought input. These vital responses assist with the birthing process, help the newborn survive life outside the womb, and aid in developing the foundation for motor and cognitive competence.
A Functioning Central Nervous System
The presence of a reflex is an important sign of nervous system development and function, and they help doctors identify normal brain activity. Many neonatal reflexes fade away as the child grows older, although some are retained throughout adulthood. However, a reflex that remains long after the age when it would usually disappear can be a sign of neurological malformation or damage.
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Sucking and Swallowing Reflexes
The first survival reflexes develop in the womb. By seven and a half weeks after conception, the sucking reflex can be observed. During this period, the foetus may be seen sucking its thumb, yawning, or swallowing. By birth, the sucking and swallowing reflexes are ready for use and crucial to infant nutrition. When a nipple or bottle is placed in your baby’s mouth and touches the roof of her mouth, she automatically begins to suck. This reflex lasts until she is around one-year-old.
Although this is a reflexive action, not all infants suck
efficiently at first because coordinating rhythmic sucking movements
with breathing and swallowing is a relatively complicated task. With
practice, however, the reflexes become second nature.
Your baby is born with a rooting reflex which prompts her to turn her head toward anything that strokes her cheek or mouth. This helps her find the nipple during feeding time. At first, she’ll root from side to side, turning her head towards the nipple or bottle, and then away in steadily decreasing arcs. But by about three weeks, she’ll simply turn her head and move her mouth directly into position to suck. The reflex disappears at around four months as the child gains control of its own head movements.
The Moro reflex is triggered by sensory overload. A loud noise, bright light, or sudden stimulation of the balance mechanism (if your little one feels like she is going to be dropped or tilted in excess), turns on this reflex, which is usually fully developed at birth and disappears after two months. Your baby reacts by arching her head back, throwing out her arms and legs, and extending her neck, then rapidly pulling her legs up and bringing her arms together while crying loudly. The first phase would help if the child were falling, while the second phase acts to make it easier for her to grasp onto someone to aid the protection of vital organs. This reflex matures into the startle response, a lifelong reflex manifest in a sudden involuntary move backwards in the presence of perceived danger.
Palmer Grasp and Plantar Grasp Reflexes
When you place a finger in your baby’s palm, the palmer grasp reflex is triggered and she clenches her other fingers strongly around the finger in her hand. This reflex has diagnostic significance in infants. This means that an absence or a weak response of the reflex may reflect peripheral nerve or spinal cord involvement or predict the development of athetoid cerebral palsy. You’d also notice a hyperactive response of the reflex in children with spasticity in their upper limbs.
The plantar grasp reflex is similar to the palmar grasp reflex in that stroking the ball of the foot causes the foot and toes to curl, grasping whatever caused the stimulus.
The plantar grasp reflex appears to initiate many of the motor
movements made by the infant. If the plantar grasp reflex is retained,
it may lead to balance and coordination difficulties, which in turn affect walking.
These reflexes decrease over time and usually disappear by six and 12 months of age, respectively. Their disappearance is significantly related to the onset of your little one’s voluntary use of hands and legs.
Asymmetrical Tonic Neck Reflex
The asymmetrical tonic neck reflex is initiated when laying babies on their back and turning their head to one side. The arm and leg of the corresponding side should extend while the opposite side bends. This reflex serves as a precursor to hand-eye coordination and should disappear by six months of age. Head turning activates the vestibular system through the shifting of fluids in the inner ears. Moreover, the reflex also encourages the development of language recognition and expression.
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