What is the Asymmetrical Tonic Neck Reflex (ATNR)?

by Jessica Hill, COTA/L July 08, 2021

What is the Asymmetrical Tonic Neck Reflex?

The Asymmetrical Tonic Neck Reflex (ATNR) is one of many infant primitive reflexes - an involuntary movement pattern that we are all born with. The ATNR is often called the “fencing reflex”, due to the fact that when an infant is lying on their back and their head is turned to one side, the arm on that same side will extend while the opposite arm will flex in towards the body - looks like they’re ready to start fencing!

The ATNR is elicited by a simple head turn to either the right or the left. The kicking that is felt in utero is due to the ATNR! Additionally, the ATNR plays a role in the birthing process by assisting with “unscrewing” down the birth canal. Because the ATNR is elicited with head movement, it is also connected directly to the vestibular system (the vestibular system is activated by head movement and head position changes), which affects balance and muscle tone. Another big role that the ATNR takes part in is hand-eye coordination and developing skills on each side of the body - think of turning your head to reach and grab an item.

The ATNR develops at approximately 18 weeks in utero, should be fully developed by birth, and should integrate by six months of age. This is around the same time that the Moro and Palmar Grasp reflexes are also integrating, as well as around the same time, the infant is intentionally reaching for objects, has gained head control, and may start crawling.

How does the ATNR integrate?

Although there is no one scientific method to ensure full primitive reflex integration, there are some things to take into consideration when discussing the integration of the ATNR.

baby play

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!

  • Natural movement is always a fantastic option - instead of carrying your newborn in a carrier or stroller, use a wrap to carry your newborn on your body to provide more natural movement.
  • Carry your infant in different positions - on their tummy, back, side, etc. This will provide movement in different planes and will promote head-turning, thus activating the ATNR and providing natural development opportunities.
  • Tummy time. We’ve all heard it over and over again - tummy time is a must! A systematic review from 2020 identified that tummy time was positively associated with gross motor and total development. But how do you start tummy time with a newborn? Simply laying your newborn on your chest, on their tummy, is a great place to start. Then incorporating tummy time into everyday, waking play will begin to establish a routine and improve tolerance in the long run.
  • Placing toys in different planes that baby has to reach for - both sides of the body, in front of the body, behind, etc. Also, promote visual tracking - thus facilitating head turns - by moving preferred toys around the body, slowly and at eye level or slightly above.
  • A variety of sights, sounds, smells, and tactile experiences. The more variety and the more frequent, the better!

Because every newborn is different and every experience is different, there’s no one way to guarantee that the ATNR will be successfully integrated by six months of age. However, you can feel more confident that your baby is getting the sensory experiences necessary for potential primitive reflex integration by using the above strategies.

What factors can contribute to an unintegrated ATNR?

A study looking at the persistence of primitive reflexes and associated problems in children identified these potential factors for unintegrated primitive reflexes, including the ATNR:

  • Stress during pregnancy
  • Substance abuse during pregnancy
  • Cesarean section birth
  • Brain damage during labor
  • Premature and low birth weight
  • Significant illness during the first year of life
  • Insufficient stimulation and tummy positioning
  • Lack of free movement time on the floor
  • Stressful environment
  • Not enough nourishment/insufficient weight gain

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 consider if your child has an unintegrated ATNR.

What does an unintegrated ATNR look like?

Because the ATNR is directly related to the vestibular system and consists of a physical reaction, it has a direct impact on movement, balance, muscle tone, and coordination. Additionally, due to the movement of the arm in relation to the head, it also has a direct impact on hand-eye coordination.

Symptoms related to an unintegrated ATNR in older children are:

  • Challenges with crawling as an infant
  • Decreased engagement with toys as an infant
  • Poor balance when learning to walk
  • Gravitational insecurity and fear with movement
  • Challenges crossing midline
  • Poor hand dominance establishment
  • Challenges with reading and writing
  • Left / right confusion
  • Challenges with visual tracking
  • Poor coordination for bilateral integration tasks
  • Dyslexia and/or Dysgraphia

Watch How to Assess for Retained ATNR

What can I do if my child has an unintegrated ATNR?

If your child exhibits any of the above symptoms/challenges, the first step will be 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), cranio-sacral 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 ATNR.

For babies, decreasing the amount of waking time spent in containers is the best way to integrate the ATNR. 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 objects in their environment. If safety is a concern during tummy time, 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 and visual tracking.

  • While in tummy time, place toys to the left and the right side, not just in front. Use noise and gentle lights to engage the visual system and encourage head turns to look at objects.
  • While laying on back, hold a preferred toy (with lights and/or sounds) above, at eye level, and slowly move the toy to the left then back to the middle and then to the right, making sure you move it far enough that baby gets a full head turn.
  • While out and about, point to objects in the environment to help baby turn head to look in all directions.
  • Encourage more crawling activities. Use pop up tunnels, create tunnels using chairs and blankets, etc. Try to engage the child visually to facilitate head turns while they are crawling.
  • Facilitate crawling across a variety of floor textures and thresholds. This is where obstacle courses come in handy!

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.

  • Set up a matching game on the floor - place colored pieces of paper on the floor in a semi-circle around the child, who will lay on their stomach. Call out a color and have the child reach to tap the color. Encourage crossing midline - reaching with left hand to tap a color on the right, and vice versa.
  • Try a “mummy” walk. Walking forward, reach arms straight out in front and keep them there, almost like pointing forward. Slowly turn head to the right, then the left, while maintaining arm positions and walking forward. Ensure that you get a full head turn - chin over shoulder! And be sure to do it slowly. The arms will try to move, so be sure to keep them in front!
  • Place two visual charts (something simple like this) on two chairs. Get on hands and knees (in a crawling position) in between the chairs and charts, so that the charts are at eye level, one on each side. While maintaining your position, slowly look to one of the charts, read an item, then turn your head to the other and read an item. Continue alternating back and forth, making sure to maintain a good stable body position.

If your child is struggling with some of the signs/symptoms associated with an unintegrated ATNR, try some of these strategies:

  • Poor balance and/or fear with movement:
    • Start slow. Complete slow swinging tasks. Complete simple balance activities with balance beams, hopping on one foot, etc. Try balancing on one foot with eyes closed - time it and try to beat your time!
    • Complete simply bouncing and rolling activities with a round therapy ball - give them control over the movement to feel safer.
  • Poor hand dominance establishment after the age of 7:
    • Determine which hand your child performs best with and ensure they consistently use that hand for fine motor tasks such as writing and self-feeding.
    • Discuss this with your child - “I notice you have more control when you use your ___ hand. Let’s try to use that hand again!”
    • Use a visual marker to help them establish consistent use of their dominant hand, such as a hair tie or bracelet on that hand.
  • Challenges with reading, writing, and/or Dyslexia:
    • Talk with your child’s teacher to discuss strategies such as decreasing amount of required writing.
    • Use highlighter strips while reading to decrease extra visual stimuli.
    • Seek out a trained Dyslexia specialist.
    • Use a multi-sensory approach when practicing writing. Try using index finger of dominant hand to write letters in sand, shaving cream, etc.
    • Dance, sing and incorporate movement into learning activities.
  • Challenges with visual tracking:
    • Try games like Zoom Ball and balloon volleyball.
    • Try marble mazes.
    • Seek out Vision Therapy.
  • Poor bilateral integration / coordination:
    • Practice! Complete jumping jacks (use a mirror for visual feedback) and other games that require both sides of the body to coordinate together.
    • Complete cross crawls- touching opposite elbow to opposite knee while balancing on one leg.
    • Games like cat’s cradle.
    • Obstacle courses are extremely helpful!

One last note

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 ATNR 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!

Check out our video all about the ATNR!


Check out our video on Primitive Reflexes in Infancy



Do you prefer to listen to your content? Check out our podcast episode where we discuss ATNR!

Want to become an expert on Primitive Reflexes?

Be sure to check out our full Primitive Reflex Integration Training!

Jessica Hill, COTA/L
Jessica Hill, COTA/L

Jessica Hill, COTA/L, CPRCS is Harkla's in-house Certified Occupational Therapy Assistant (COTA) and Certified Primitive Reflex Clinical Specialist. She has been working with children for over 6 years in outpatient settings. Jessica specializes in creating easy-to-digest, actionable content that families can use to help their child's progress at home. Jessica is the in-house expert, content creator, and one of the podcast hosts at Harkla! To learn more about Jessica, visit the Harkla About Us Page. Make sure to listen to her weekly podcast, All Things Sensory by Harkla for actionable, fun advice on child development.

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