The Symmetric Tonic Neck Reflex (STNR) is one of many infant primitive reflexes - an involuntary movement pattern that we are all born with. However, the STNR is not actually present until after birth - it appears between 6 and 9 months of life. This is due to its correlation with the TLR (Tonic Labyrinthine Reflex) - as an infant begins to integrate the TLR, the STNR emerges to help progress to the next phase of development, crawling.
The STNR divides the body in half - lower half and upper half. There are also two movement patterns - flexion and extension. As the infant moves from prone (on belly) to quad (on hands and knees), they will begin to extend their neck - look up, and flex their neck - look down. These movements will then elicit a response in the upper and lower limbs. During neck extension, the arms will straighten while the legs will flex/bend. During neck flexion, the opposite will occur - the arms will flex/bend while the legs will straighten - moving the infant into a somewhat down dog position.
The life span of the STNR is very short - just 2-3 months. That is because as the infant moves from prone to quad, they will begin to start learning how to crawl. As they learn to crawl, the STNR will start to integrate.
The “rocking” movement that infants do while on hands and knees, right before they begin to crawl? That may be the STNR beginning to integrate! The STNR should be fully integrated - no longer present - by 11 months of age.
Although there is no one scientific method to ensure full primitive reflex integration, there are some things to consider when discussing the integration of the STNR.
Let’s talk about sensory integration. By providing an infant with different types of sensory stimulation, new neural pathways will be developed in the brain, thus stimulating new movement and cognitive development. An article on sensory integration discussed that the engagement in sensorimotor activities promoted adaptive behaviors via neuroplastic changes - simply put, by experiencing different types of sensory activities, our brains can change and thus promote new behaviors!
So what types of sensory activities should you provide to your newborn infant? Keep it simple!
Because every infant is different and every experience is different, there’s no one way to guarantee that the STNR will be successfully integrated by 11 months of age. However, by using the above strategies, you can feel more confident that your baby is getting the sensory experiences necessary for potential primitive reflex integration.
Potential factors for unintegrated primitive reflexes, including the STNR are:
Additionally, if a child has successfully integrated their primitive reflexes, a sudden or chronic bout of trauma, stress or injury can re-activate these reflexes.
While there is no guarantee for reflex integration, there are contributing factors to take into consideration if your child has an unintegrated STNR.
As previously mentioned, the STNR is linked with the TLR as well as has a direct correlation to muscle tone, upper and lower body movements, and head movements. These connections go even further to include vision and ocular motor skills, balance, and coordination.
Symptoms related to an unintegrated STNR in older children are:
If your child exhibits any of the above symptoms/challenges, the first step is to talk with your pediatrician. Discuss your concerns - if your pediatrician is familiar with primitive reflex integration, they may already have a plan of action ready. If your pediatrician is unfamiliar with primitive reflex integration, feel free to share what you've learned! If you ever feel uncomfortable or that your concerns are being pushed to the side, don’t be afraid to seek out a new pediatrician.
Many Occupational Therapists (OT) are trained in primitive reflex integration techniques. Seek one out! Talk with friends and family members to see if they know anyone specific. Use Facebook groups and Instagram to find someone who has training. Physical Therapists (PT), craniosacral therapists, and chiropractors may also have knowledge of primitive reflex integration. It can take some time to locate the right professional, so don’t give up!
Meanwhile, there are some different exercises and play activities that you can incorporate into your child’s daily routine that can help promote the integration of the STNR.
For babies, decreasing the amount of waking time spent in containers is the best way to integrate the STNR. These are things like bouncers, jumpers, walkers, etc. When baby is awake, provide natural movement opportunities, plenty of tummy time, and opportunities to visually track and reach for objects in their environment. If safety is a concern during tummy time or pre-crawling, opt for something like a pack and play instead of a container that doesn’t allow for natural movement.
If your child is young, under three years old, focus on developmental movements.
If your child is older, you can still focus on the same developmental movements and increase the challenges, as well as try some other activities.
If your child is struggling with some of the signs/symptoms associated with an unintegrated STNR, try some of these strategies:
As you continue on your path through primitive reflex integration, keep in mind that your child is unique and there's nothing wrong with them! Even if they have an unintegrated STNR and seem to be struggling more than other children, your job is to help guide them along the way and provide as much support as possible.
You and your child are doing the best you can with what you have, so keep researching and keep trying new things until you find what works. Even then, keep searching because what works now might not work forever, especially as your child grows and develops through different seasons of life!
Want to listen to more information on the STNR? Check out our podcast episode on it!
Want to become an expert on Primitive Reflexes?
Be sure to check out our full Primitive Reflex Integration Training!
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At birth, primitive reflexes are present to assist in survival - most develop in utero. Primitive reflexes should integrate - go away or develop - around 12 months of age, some closer to two or three years old. Read this article to learn what reflexes newborns have, how to know if they integrate, and how to help if they don't!