Sensory processing
The STNR: The Reflex Behind the Crawling Story, and What the Evidence Says
The symmetric tonic neck reflex is one of the three most often found still active in school-age children. Here is what is actually known about it, including where the references go quiet.
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The symmetric tonic neck reflex — the STNR — links head position to what the arms and legs do: bending or extending the neck changes flexion and extension in the limbs. It is described as one of the brainstem-mediated automatisms that typically integrate during the first year of life.3 Two things make this page different from the others in the series. First, the standard clinical reference names the STNR without giving it an integration window at all, where it gives one for the Moro, the ATNR, the palmar grasp and the Galant.1 Second, it is one of the three reflexes most frequently found still active in school-age children, and therefore one of the most often cited in commercial programs.2 Both are worth knowing before weighing a recommendation built around it.
What the STNR is
The symmetric tonic neck reflex ties head position to limb tone: flexing or extending the neck produces a corresponding change in flexion and extension in the arms and legs. Along with the ATNR and the TLR it is described as a brainstem-mediated automatism that, in typical development, integrates within the first year of life.3
The crawling story. The STNR is the reflex most often invoked in the claim that a child “skipped crawling” and that this matters later. Crawling is not a milestone every typically developing child passes through in the same way, and the reflex literature does not establish that skipping it causes later difficulty. What the evidence does say is set out below.
Where the standard reference goes quiet
This is unusual enough to state directly. The StatPearls primitive-reflex chapter gives an appearance point and an integration window for the Moro, the ATNR, the palmar grasp, the plantar grasp, the Galant, the stepping reflex and the Babinski. For the STNR it gives neither — the reflex is named as one of seven dimensions in an assessment scale, and that is all.1
That does not mean the STNR is not real or not worth assessing. It means that if a program is built around integrating it by a particular age, the age is not coming from the same place the Moro's is.
What the evidence actually shows
It is one of the three found most often. A 2026 systematic review of 14 studies in children aged 3 to 11 without neurodevelopmental diagnoses found the ATNR, the STNR and the TLR to be the reflexes most frequently observed still active.2
The ADHD association has a number on it. A meta-analysis of four studies and 229 participants found a moderate positive correlation between ADHD and these reflexes: r = 0.48 for the ATNR and r = 0.39 for the STNR.4
How to read r = 0.39. It is a real, moderate association across a group. It is not a test, it does not predict an individual child, and four studies with 229 participants between them is a small base for a strong claim. The same review's authors describe the field as being at an initial stage.4
Motor and academic associations exist too. In the same 2026 review, all six studies of motor development reported negative associations — particularly locomotion, balance and manual dexterity — and six more linked persisting reflexes to lower performance in reading, spelling and mathematics.2 These are associations across groups, not mechanisms in a child.
What about doing something about it
The 2026 review found five studies evaluating interventions aimed at reducing persisting reflexes. Most reported improved developmental outcomes, with effect sizes ranging from small to large — and the review concluded in the same breath that the available evidence “remains limited and heterogeneous” and should be read with that in mind.2
That is a fair summary of where this sits: promising enough to study, not settled enough to sell as a course. Occupational therapy guidance is explicit that a retained reflex does not automatically mean impairment.5
If you have been told your child has a retained STNR
The questions worth asking are on the parent article, and they matter more here than for the reflexes with clear infant timelines — because with the STNR there is no standard integration age to check the claim against.
Frequently asked questions
What is the STNR?
The symmetric tonic neck reflex. Flexing or extending the neck produces a corresponding change in flexion and extension in the arms and legs. It is described as a brainstem-mediated automatism that typically integrates during the first year of life.
At what age should the STNR integrate?
The standard clinical reference used here names the STNR without giving it an integration window, while giving one for the Moro, ATNR, palmar grasp and Galant. If a program specifies an age, it is worth asking where that age comes from.
Is the STNR linked to ADHD?
A meta-analysis of four studies and 229 participants found a moderate positive correlation — r = 0.39 for the STNR and r = 0.48 for the ATNR. That is a real association across a group. It is not a test, it does not predict an individual child, and it is a small evidence base.
Does skipping crawling mean a retained STNR?
That claim is common and is not established. Crawling is not a milestone every typically developing child passes through the same way, and the reflex literature does not show that skipping it causes later difficulty.
Sources
- Chamarthi VS, Gunasekaran V, Daley SF. Primitive Reflexes: Comprehensive Neurological Assessment Across the Lifespan. In: StatPearls. StatPearls Publishing; updated 2026. ncbi.nlm.nih.gov/books/NBK554606 (PMID 32119493). Checked August 25, 2026.
- Provazník A, Musálek M, Bob P, Větrovský T, Malambo C, Silva AF, Anderson D. Persisting primitive reflexes and motor and cognitive development in children: a systematic review. Acta Psychologica. 2026;266:106915. doi:10.1016/j.actpsy.2026.106915 (PMID 42061063).
- Bijle MA, Malawade M. Effectiveness of reflex integration exercises on sensory-motor outcomes in children with autism spectrum disorder: a quasi-experimental study. Cureus. 2026;18. doi:10.7759/cureus.111970 (PMID 42544248). Cited here for its description of the ATNR, STNR and TLR as brainstem-mediated automatisms that typically integrate within the first year.
- Wang M, Yu J, Kim HD, Cruz AB. Attention deficit hyperactivity disorder is associated with (a)symmetric tonic neck primitive reflexes: a systematic review and meta-analysis. Frontiers in Psychiatry. 2023;14:1175974. doi:10.3389/fpsyt.2023.1175974 (PMID 37484683).
- American Occupational Therapy Association. Practice guidance on reflex integration programs and occupational outcomes. Checked August 19, 2026.
Medical disclaimer. This page is for general educational purposes and does not constitute medical advice, diagnosis, or treatment. Sensory and motor concerns are best assessed by an occupational or physical therapist who can evaluate your individual child.