In the womb, babies develop primitive reflexes that are integral to their survival and future development. But, what are primitive reflexes? They are a set of special reflexes that develop in the brain stem before birth. They help the baby with positioning in the womb, birthing, breathing, feeding, urination, etc. Throughout the first year of life these primitive reflexes go away or “integrate” as higher levels of the brain develop into more mature or voluntary movement. If primitive reflexes do not integrate, they can interfere with the neurological organization of the brain which may limit developmental and academic skills. If any reflexes remain after 12 months of age, they are called retained primitive reflexes. Each primitive reflex comes with its own set of movements and leads to new and different developmental milestones.
Palmar Primitive Reflexes
Firstly, there is the palmar reflex, which is important for the development of purposeful grasping. You may see by placing an object in the palm of an infant’s hand. Their reflex response is to hold on to the object. Children with a retained palmar reflex may: fatigue easily with handwriting or fine motor tasks, have sensitive palms, open and close their mouths while using their hands for tasks (writing or cutting), and/or difficulty with speech articulation. The mouth and hands connect via neural pathways in infancy, therefore the connection is still strong in those who have retained the palmar reflex.
Moro Primitive Reflexes
The Moro reflex, or the startle reflex, causes a baby to stretch out their arms and legs and quickly bring them back in with jerky movements. This response is similar to the feeling of falling, a loud sound, or a drastic change in temperature. Children with a retained Moro reflex are often sensitive to stimuli (sounds, textures, lights), lack emotional and self-regulation skills, and have a difficult time paying attention in class. Without an integrated Moro reflex, a child’s fight or flight response may be active, easily causing difficulties in many areas of life.
Asymmetrical Tonic Neck Reflex
The asymmetrical tonic neck reflex (ATNR) is important to build connection between the hand and eyes. The reflex builds skills to develop each side of the body, hand-eye coordination, and helps to build muscle tone. While infants are on their bellies, the arms and legs move as the baby turns their head. Therefore, they are exposed to a ton of visual stimulation by looking at their arms moving, looking at objects in the environment, and grabbing toys. Children with a retained ATNR may have challenges with the following: crawling, handwriting, visual tracking, crossing midline, and coordination.
Symmetrical Tonic Neck Reflex
The symmetrical tonic neck reflex (STNR) assists the infant with moving from laying on their belly onto hands and knees. This is sometimes referred to as the crawling reflex. It helps with the flexion and extension of the baby’s upper and lower extremities. Therefore, children with a retained STNR may have: difficulty crawling, poor posture and low muscle tone, W-sitting, and poor sustained attention.
While there are many more primitive reflexes, these are some of the most common ones that OTs address in therapy. We are all born with primitive reflexes. They should naturally integrate in order to promote higher level learning and motor development. However, sometimes they don’t. This can potentially cause challenges for children. An occupational therapist can test for any primitive reflexes and assist with integrating any retained reflexes.
For more information regarding primitive reflexes and signs to look for check out this great handout from Solve Learning Disabilities.