The Asymmetrical Tonic Neck Reflex (ATNR), often called the “fencing reflex,” is an automatic movement pattern present in infants. This primitive reflex is an involuntary action governed by the brainstem, playing a role in a newborn’s initial survival and development. Integration is the process where the maturing central nervous system inhibits this reflexive movement, allowing for the development of complex, voluntary motor skills. If integration does not happen naturally, the retained reflex can interfere with the later acquisition of skills like coordination, balance, and visual tracking. The goal of ATNR integration exercises is to stimulate the nervous system to inhibit the reflex, laying a stronger foundation for higher-level learning and movement.
The Role of the ATNR in Early Development
The ATNR first emerges in utero around 18 weeks gestation and is fully present at birth. Its characteristic posture occurs when the head is turned to one side: the arm and leg on that side extend, while the opposite limbs flex. This pose is sometimes referred to as the “bow and arrow” or “fencer position.”
The reflex assists the baby’s passage through the birth canal by facilitating a corkscrewing motion. After birth, the ATNR is important for training the visual system and developing early hand-eye coordination. It encourages the baby to look at the extended hand, which is a foundational step for future reaching and grasping movements. The ATNR should naturally integrate around four to six months of age as the infant gains greater voluntary control over their head and limbs.
Indicators of an Unintegrated ATNR
If the ATNR does not integrate on schedule, it remains an involuntary response that interferes with voluntary movement patterns. This retained reflex often manifests as difficulties requiring coordination between the two sides of the body. A common sign is difficulty crossing the body’s midline, which impedes tasks like reading across a page or reaching for an object on the opposite side.
In older children, this interference can lead to poor handwriting skills, often characterized by an excessively tight pencil grip. An unintegrated ATNR also contributes to challenges with balance when the head moves and issues with visual tracking, such as losing one’s place while reading. Children may also struggle with bilateral movements, such as catching a ball or learning to ride a bicycle.
Core Integration Exercises and Techniques
Integration of the ATNR is accomplished through specific movements that mimic the reflex pattern while introducing control and cross-lateral coordination. A fundamental exercise is the Lizard or Robot Crawl, performed while lying on the stomach. The person turns their head to one side, extends the arm and leg on that side, and bends the opposite arm and leg, holding the position before slowly switching sides. This exercise targets the reflex pattern while forcing the brain to inhibit the reflexive limb movement.
Another effective technique involves Cross-Lateral Movements while on hands and knees, known as the Creeping Crawl. This requires moving the opposite arm and leg forward simultaneously, such as the right hand and left knee. This encourages the dissociation of head movement from limb movement, building neural pathways necessary for bilateral coordination.
A more advanced movement is the ATNR Switch-Up, performed while seated, focusing on visual fixation and controlled limb movement. The individual sits with back support, extending one arm and the opposite leg while flexing the other arm and leg, keeping their eyes fixed on the extended hand. The movement requires a smooth, coordinated switch of limb positions, promoting eye-hand coordination and independent limb movement.
Implementation and Consistency for Success
Effective ATNR integration relies on consistent practice rather than intense, lengthy sessions. A typical program involves performing exercises for a short period, generally five to ten minutes, one to three times per day. The duration is highly individualized, but integration often requires sustained effort over a period ranging from a few weeks to several months.
Movements must be performed slowly and deliberately, focusing on accuracy and control. Establishing a positive, low-stress environment is helpful, as stress can sometimes exacerbate reflexive responses. While these exercises can be implemented at home, seeking guidance from a professional, such as a physical or occupational therapist specializing in primitive reflex integration, is highly recommended. These professionals can accurately assess retained reflexes and tailor a specific program to ensure proper technique and successful integration.