What is ATNR|Retained ATNR |Signs & Symptoms of Retained ATNR

ATNR or asymmetrical tonic nerve reflex is a primitive reflex, found in newborn babies. It normally remains until 6 months of the child’s age.

It emerges in utero after 18 months of conception and is seen and identified within 3 months after birth.

The reflex gets initiated when the head moves to the right and left side while lying on the back. The turning of the head leads to the extension of the arms and legs of one side and flexion of the other side of the legs and arm.

Turning the head to the right causes the right arm and leg to extend and the left arm and left leg to flex. Due to this pattern, it is also known as the fencer’s reflex. It looks like the little one is holding a fencer’s pose.

ATNR begins in the womb and stays till 5-7 months of age. But in some babies, ATNR does not integrate properly. They still exhibit the reflex beyond the average timeline. This is believed to be associated with developmental delays. The condition is called retained ATNR.

If the baby continues to show ATNR even after 7 months, it is known as retained ATNR. Some researchers link ATNR to potential developmental delays that could present themselves for years after infancy.

Studies found that retained ATNR could negatively affect children’s reading capabilities.⁽¹⁾

Some reflexes that could be linked to retained primitive reflexes include:

• The poor hand-eye coordination
• Difficulty in visual tracking
• Difficulty with handwriting specifically involving tight grip
• Dyslexia
• Difficulty in translating ideas into written text

A study found a link between retained primitive reflexes and delayed motor development in low birth weight babies.⁽²⁾

Another study done in 2018 found 4-6 children who retained primitive reflexes, had reduced motor development skills.⁽³⁾

As noted in the 2019 continuing education module, the American occupational therapy association found it as a very controversial subject.⁽⁴⁾

There is a large gap between, when a baby should have integrated ATNR and when they might experience reading and writing developmental delays.

Those who believe there is a link between non-integrated ATNR and developmental delays, there are certain signs that if taken care of can minimize the potential developmental and learning delays. The signs include:

• Poor balance on sitting and standing as the baby moves
• Jerky eye movements
• Struggling in crossing the midline of the body with their arms and legs

In older children the signs shown are:

• Difficulty in throwing and catching a ball
• Difficulty in concentrating
• Struggling with handwriting
• Struggling to multitask
• Using both hands to write interchangeably
• Using a tight pencil grip
• Difficulty in learning to ride a bike

These symptoms are just a theory. For the best course of treatment for a child’s unique situation, it is good to speak with a doctor.

If a baby struggles in keeping balance or have difficulty with visual tracking, an atypical presentation of ATNR can be explored.

In older children, the signs and symptoms mentioned above can be looked for. If there are any concerns about the child’s development, a pediatrician should be consulted. An evaluation by an occupational therapist may also be required.

If the pediatrician agrees that the ATNR has not integrated, they may work by performing simple exercises, games and activities as per the child’s age.

The main goal of the treatment is to create movements that mimic the early reflex movement and create learned neural pathways that would help integrate ATNR.

Not all occupational therapists believe there is a link between developmental delays and retained primitive reflexes like ATNR. More research is needed to clearly identify the link.

ATNR is one of the many reflexes that are seen in the baby as they are born. If concerned that your child is exhibiting developmental delay consult a pediatrician for a better opinion.