Retained (primitive) motor reflexes are involuntary movement patterns directed by the brainstem, meaning they are not under conscious control. They emerge in-utero and during the early weeks/months of life play an essential role in infant survival and development.
These reflexes have a limited life span and lay the foundation for more precise movement. For ideal development, they should become integrated during the first year of life to allow for more complex movement patterns controlled by higher levels of the brain.
The persistence of these reflexes can indicate issues in neurological development and immaturity within the nervous system. They can interfere and prevent the development of succeeding postural reflexes. Postural reflexes are necessary to support mastery of head control and muscle tone that provide accurate balance, movement and stability to allow the child to control voluntary movement and successfully orient the body in coordination with the visual system.