Asymmetrical Tonic Reflex

The asymmetrical tonic reflex (ATNR) is a primitive reflex in infants. In order to elicit a correct response, the infant starts in the supine, lying on back, position. Once in position, the infant's head is turned to the side. The normal response is displayed by same side arm and leg extension.¹

Normally the ATNR weakens and then becomes extinct after an infant reaches six months. A retained ATNR has developmental consequences as a child grows. In infancy, actions such as rolling over and crawling become difficult. In childhood, persistent ATNR prevents actions that cross the midline of the body. Retained ATNR is often associated with dyslexia and ADHD.²

^{Certain exercises may be performed to help alleviate the strength of the reflex as seen below.}

https://www.youtube.com/watch?v=XzHRVy-t2Z0

1. Haywood, K., & Getchell, N. (2009). Life span motor development. Champaign, IL: Human Kinetics.

2. ATNR - Occupational Therapy for Children. (n.d.). Retrieved August 02, 2016, from http://occupationaltherapyforchildren.over-blog.com/article-atnr-105923600.html

Babinski Reflex

One of the more known reflexes, even if not by name, is the Babinski reflex. The Babinski reflex occurs when the infant's lateral aspect on the plantar surface (outside sole) is stroked from heel to toe. The response to this stimulus is displayed by the infants toes extending outward. After birth, doctors use this reflex to test for neurological function.

Video of reflex¹ -- https://www.youtube.com/watch?v=oI_ONptx2Ns

The Babinski reflex is a primitive reflex, which connotes emergence at birth. Generally in normally developing infants this reflex disappears around four months of age. However, typically primitive reflexes weaken or modify within the first two weeks. Warning signs of an underlying neurological condition occurs when the reflex persists after six months or never appears at birth.²

Adult testing with explanation ³ --https://www.youtube.com/watch?v=kOq5Np0eZ6A


1. B. (2010). Babinski reflex / reaction of a baby. Retrieved July 29, 2016, from https://www.youtube.com/watch?v=oI_ONptx2Ns
2. Haywood, K., & Getchell, N. (2009). Life span motor development. Champaign, IL: Human Kinetics.
3. B. (2008). Babinski Reflex. Retrieved July 29, 2016, from https://www.youtube.com/watch?v=kOq5Np0eZ6A

Introduction

Hello, my name is Dakota and I am an undergraduate student studying kinesiology at Michigan State University. Throughout the duration of this blog, I will analyze various infantile reflexes and reactions. Areas of emphasis will include emergence and extinction patterns in normal developing infants, as well as, non-normal infant trajectories of growth. Normal within the context of this blog indicates an infant born full-term and with no underlying conditions that affect motor development. Non-normal indicates a preterm birth and/or the presence of a condition that affects motor development. For example, cerebral palsy (CP) and developmental coordination disorder (DCD) are two conditions known to affect motor development. In this blog, I will show the normal patterns of growth parallel to non-normal growth patterns.