The Asymmetrical Tonic Neck Reflex (ATNR) is a primitive reflex observed in infants, developing in utero and present at birth. Often called the “fencer’s reflex,” it causes the arm and leg on the side an infant’s head turns to extend, while the opposite limbs flex. Normally, the ATNR integrates as the brain matures, generally by 4 to 6 months of age. If this reflex persists beyond this period, it can indicate developmental considerations.
Recognizing Persistent ATNR in Older Children
Persistent ATNR can manifest in various difficulties in older children. A common sign is challenges with handwriting, including a poor pencil grip, leaning their head on the table, or struggling with writing fluency. These difficulties arise because the reflex can cause the arm on the side the head is turned towards to extend, making precise hand movements difficult.
Children with persistent ATNR may also struggle with activities requiring hand-eye coordination, such as catching or hitting a ball. Their balance can be affected, particularly when moving their head from side to side. They might also experience difficulties with bilateral coordination, making tasks like skipping or riding a bicycle challenging. Issues with visual tracking, poor spatial awareness, and difficulties crossing the body’s midline are frequently observed.
Administering the ATNR Test
A simple home test can help determine if the ATNR might still be present in an older child. One method involves having the child stand with feet somewhat close together and arms extended straight out at shoulder height, with wrists relaxed. The child then closes their eyes and slowly turns their head to the right, attempting to keep their arms perfectly still for about ten seconds. This is repeated by turning the head to the left. A positive response is indicated if the arms drift, bend at the elbows, or if the shoulders turn in the same direction as the head.
Another test involves having the child get into a hands-and-knees position, ensuring their back is flat and head is facing forward. The child then turns their head to one side while trying to keep their arms and legs stable. If the reflex is retained, the arm on the side the head is turned to may extend, the opposite elbow might bend, or the body might shift. The child’s ability to maintain their position without significant arm or body movement suggests the reflex is likely integrated.
Understanding Test Outcomes and Follow-Up
If a child exhibits a positive response during these screening tests, it suggests the Asymmetrical Tonic Neck Reflex may not have fully integrated. This home assessment serves as a preliminary screening tool, not a definitive diagnosis. Persistent ATNR beyond the typical age can indicate developmental delays.
It is important to consult with a healthcare professional if a persistent ATNR is suspected. A pediatrician can provide initial guidance and may recommend further evaluation by specialists such as an occupational therapist, physical therapist, or developmental specialist. These professionals can offer a proper diagnosis and develop a tailored plan. Therapies, including reflex integration activities, can be beneficial but should be implemented under professional guidance.