Asymmetrical Tonic Neck Reflex (ATNR): What It Is and Why It Matters
The Asymmetrical Tonic Neck Reflex (ATNR) is a primitive reflex that appears before birth and helps babies with their earliest movements. This guide explains what the reflex looks like, when it normally fades, and what current research does and doesn’t tell us about it.
What is the Asymmetrical Tonic Neck Reflex?
When a baby’s head turns to one side, the arm and leg on that side straighten while the opposite arm and leg bend. Because the pose looks like a fencer’s stance, it is often called the “fencing position”.
The reflex is automatic. Babies don’t choose it, and it happens without their control.
When does the ATNR appear and fade?
The ATNR appears about 18 weeks before birth and is most noticeable between one and four months of age. It usually fades between about three and nine months as babies gain more voluntary control of their movements (StatPearls). Sources give slightly different ages, so treat these as a range.
What does the ATNR do in early development?
The ATNR is thought to support early postural tone and early eye-hand coordination, because a baby who turns their head toward a hand is more likely to look at it and reach for it. It also forms part of the movement foundations for later skills such as reaching, grasping and crossing the midline of the body.
What if the ATNR stays active in older children?
Some practitioners observe that when the ATNR remains active beyond infancy, children may find it harder to cross the midline, track objects with their eyes or manage handwriting.
The research is still developing, so it’s worth being clear about what it shows. Studies of preschool children have found that retained primitive reflexes are associated with poorer motor performance, but most of that evidence is observational and can’t show cause and effect. A review of studies on children without neurological conditions concluded that the evidence is not yet strong enough to link persistent reflexes to learning or behaviour difficulties (review).
So the ATNR is one possible piece of a child’s developmental picture, never the whole explanation. Attention, coordination and handwriting challenges can have many causes.
What parents and educators may notice
Practitioners sometimes link the following observations with an active ATNR. None of them confirms it, and none is a diagnosis:
- Difficulty crossing the midline, such as switching hands or reaching across the body
- Trouble following a moving object with the eyes
- Uneven or effortful handwriting
- A strong tendency to move the arm and leg on the side the head turns toward
Playful movement ideas
Varied movement play is good for all children. Crawling, rolling, climbing and games that cross the body’s midline all give children rich movement experiences. Our free resource on playful movement at home explores ATNR-friendly ideas in more detail on the Life Learning Academy resources page.
When to seek advice
If you’re concerned about a child’s development, talk to a GP, pediatrician, occupational therapist or another qualified professional. This guide shares general educational information and is not a diagnosis or a substitute for individual advice.
Frequently Asked Questions
At what age does the ATNR go away?
Most babies lose the reflex between about three and nine months of age, as voluntary movement takes over.
Does a retained ATNR cause dyslexia or ADHD?
No clear cause-and-effect link has been shown. Some studies find associations between retained reflexes and difficulties with motor skills, reading or attention, but the research is limited, so we treat the ATNR as one factor among many.
Can I support my child’s development at home?
General movement play, such as crawling, rolling and cross-body games, supports development for every child. If you have a specific concern, speak with a health or education professional.
Learn more about the ATNR with Life Learning Academy
If you’d like to explore the ATNR in depth, our online course explains the reflex, how to observe it and practical movement activities. It includes testing guidance, an exercise toolbox, music and movement resources, downloadable activity cards and a support plan template.