Course:KIN355/2020 Projects/Symmetrical Tonic Neck Reflex

Symmetrical Tonic Neck Reflex

Defining the Concept and Its Importance

The symmetrical tonic neck reflex (STNR) is a primitive reflex which pertains to the child’s ability to separate movements in the lower half of the body and the upper half of the body (Palmer, 2020).  There are two distinct movements involved, flexion and extension (Frothingham, 2020).  When the head is in extension, or simply when the head goes up, the arms will straighten while the legs bend.  Conversely, when the head comes down, or goes into flexion, the legs straighten and the arms bend (Frothingham, 2020).  The symmetrical tonic neck reflex facilitates the development in areas like posture, hand eye coordination, and focus, among other important body control functions (Frothingham, 2020).  Typically, this reflex emerges in a child who is around the age of 7 months and usually integrates at the age of 9 – 12 months years old (Beuret et al., 2017).  The symmetrical tonic neck reflex’s emergence and disappearance is an integral part of motor development for a child, but there are also possible adverse effects that arise if this reflex remains for longer than it should. 

One of the initial reasons why the symmetrical tonic neck reflex emerges is due to the infant’s attempts at achieving a stable position on its hands and knees coming from a supine position (Beuret et al., 2017).  Infants cannot learn to walk until they learn how to crawl, which makes this reflex significant because it facilitates crawling and creeping (Palmer, 2020).  Without the emergence and eventual disappearance of the symmetrical tonic neck reflex, babies would not be able to progress in their gross motor development.  The STNR contributes to the development of crawling as it allows the child to work on positions where they are supporting themselves against gravity by stabilizing themselves either in a position of flexion on the ground, or extension (Beuret et al., 2017).  Though crawling remains to be perhaps the biggest accomplishment that results in the emergence and disappearance of the STNR, there are several other aspects involved.

Role in Childhood Development and Contemporary Considerations

The symmetrical tonic neck reflex plays a pivotal role in childhood development and has several functions. While the STNR is known to facilitate crawling and creeping, one of the specific reasons this happens is due to the inhibition and integration of another primitive reflex called the tonic neck reflex (Beuret et al., 2017).  In this case, the STNR is partly responsible for the integration of the tonic neck reflex (TNR).  The TNR is responsible for same side extension or flexion, meaning when a child lays down on its side with their head turned, the limbs on that side will extend while the arm and leg on the other side of the body go into flexion (Frothingham, 2020).  The difference between the two reflexes is that the TNR results in either extension or flexion by the same side (both upper and lower segments), while the STNR is responsible for opposite movements between the upper and lower parts of the body essentially splitting the body in the middle (Beuret et al., 2017).  Thus, the STNR is said to help integrate the TNR as it helps prepare the infant to support itself against gravity while resting on elbows or on its hands and knees, separating body movements in the upper and lower segments (Beuret et al., 2017).  What is often noted is that once infants gain these skills, most begin to show rocking movements back and forth which is a step towards achieving milestones of creeping and crawling (Frothingham, 2020). 

While the emergence of creeping is one of the major functions of the STNR, there are others that display just as much significance.  It is also reported that the STNR helps infants pulling themselves up to a standing position using support (Beuret et al., 2017). Opposite movements between the arms and legs are key here which is why the STNR is said to have a role in acquiring this ability.  The STNR allows for flexion of the arms in order to hoist the body up, followed by the extension of the legs which will attempt to support the body against gravity (Beuret et al., 2017). 

Another reported duty of the STNR is its contribution to the development of posture necessary for standing and walking (Beuret et al., 2017).   Several curves in the spine are developed throughout an infant’s timeline, even going back to when the child is still in the womb, but the significant one that the STNR reportedly helps develop is a lordotic curve in the lumbar region (Beuret et al., 2017).  This typically occurs between 12 – 18 months of age when the infant transitions from creeping to walking.  Due to the combined effects of differentiated movements between upper and lower body, as well as proficient movement on all fours, the STNR helps develop the lordotic curve which eventually allows the infant to possess stable posture when holding an upright position (Beuret et al., 2017).

Though there are several positive functions of the STNR for childhood development, there are also consequences if the reflex fails to integrate that childhood educators and parents should be conscious of.   Often times what is noticed if the reflex isn’t inhibited, is the emergence of “bear walking” where the child walks on its hands and knees, or also the act of scooting while sitting down (Palmer, 2020).  This in turn can have a trickle-down effect and perhaps make the skill acquisition of walking more challenging.  Looking further down the timeline of a child, the retainment of the STNR also can negatively affect posture (Beuret et al., 2017).  This impact can be seen even in adults when the head is in a flexed position which results in rounded shoulders and the head poking forward (Beuret et al., 2017).  The poor posture can trickle down and even affect muscle tone in a negative way.  The retainment of the STNR can also disrupt upper and lower body integration, negatively affect hand-eye coordination, and even affect eye tracking movements (Beuret et al., 2017).  The coordination deficit that arises due to the retainment of this reflex happens because of the body’s lack of control of the arm when the head is moved down, consequently many children are messy eaters for this reason (Beuret et al., 2017).  Other studies have even reported that difficulty focusing is another consequence. (Taylor et al., 2004).

In saying all this, it is important for parents to remain calm if they notice this reflex lingering as there are exercises to help integrate the reflex, or it also just may be a case where the infant simply needs more time which is normal (Palmer, 2020).                         

Practical Applications

Game 1

Title: Creeping soccer

Purpose: To improve creeping skills and practice movements that go against the reflex.

Target age: 9-12 months

Equipment: Ball and goal of any kind, flat colored spots or pictures

Environmental set up: Open space with a clear goal, colored spots, or pictures on the floor in a zig-zag arrangement

Instructions: Start with the child on one end of an open room with the goal on the other end, the child must creep from one end of the room to the goal while pushing the ball with their hands, and creep back and forth between the spots/pictures on the floor

Modifications: if child is not creeping yet, place the child on a roller or on a block with wheels for support, or they can crawl

Game 2

Title: Partner noodle/ball crawl

Purpose: To practice movements that go against the reflex and to practice moving the upper half and lower half of the body separately.

Target age: 5+

Equipment: Pool noodle or soft ball, open space

Environmental set up: Have an open space clear of obstacles, can have a start and finish line

Instructions: Have children pair up and get into tabletop position facing each other, have them hold a pool noodle or soft ball between their foreheads and crawl from the start to the finish line without dropping the ball or pool noodle from between their heads. Once they reach the finish line, have them go back to the start line so that they each have a chance to crawl forward and backward.

Summary

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References

Beuret, L. J., Blythe, P., & Blythe, S. G. (2017). Attention, balance and coordination: The A.B.C. of learning success Wiley-Blackwell.

Frothingham, Scott. “Symmetric Tonic Neck Reflex (STNR): Definition and More.” Healthline, Healthline Media, 30 Sept. 2020, www.healthline.com/health/baby/symmetric-tonic-neck-reflex.

Palmer, Author Dr. Belinda. “Symmetrical Tonic Neck Reflex.” Friends and Family Health Centers Blog, 30 Apr. 2020, www.homewoodfriendsandfamily.com/blog/2020/02/18/symmetrical-tonic-neck-reflex/.

Taylor, M., Houghton, S., & Chapman, E. (2004). Primitive Reflexes and Attention-Deficit/Hyperactivity Disorder: Developmental Origins of Classroom Dysfunction. International Journal of Special Education, 19(1), 23-37.