Typical development in prone
Typically developing infants who are active and motivated to move usually acquire the expected abilities in prone, in a typical sequence as described in the AIMS studies of development. This occurs despite the fact that most infants do not tolerate being prone on a firm surface, and from a young age will roll from prone back into supine.
By the age of 6 months most TD infants will have developed the ability to lift their head and shoulders up off the support surface and take some weight on the fore arms and start to move around in prone.
This early development is followed by the ability to push up on extended UE, assume a prone pivot position, pivot around and start to push up into four point kneeling.
Assessment of prone development adapted for atypical development
Development in prone can be quite variable, especially in infants who have a degree of developmental delay associated with preterm birth, and who are at a high risk for cerebral palsy and infant who are hypermobile or have a very cautious nature.
Although infants with atypical development may not tolerate being prone on a flat surface, there are other options for providing infants with opportunities to develop the neck and trunk flexibility and muscle strength promoted by spent time in prone, as well as the ability to take weight on the UEs in preparation crawling.
The TOMT 0-3 assessment includes items that allow the therapist to identify different ways in which the physical environment can be adapted to allow the infant to assume a prone lying position, develop trunk extension in prone and start to explore possibilities for taking weight on the UE.
Assessment guide: neonate to 7 months
Posture and basic abilities in prone
Start by getting a general impression of the infant's abilities in prone. Let the infant lie in prone on a firm, but not hard, flat surface. Position the UEs with the hands next to or ahead of the infant's head.
► Is the infant comfortable in this position? Does the infant roll back into supine almost immediately?
► Does the infant lift the head? Is neck extension associated with extension of the thoracic and lumbar spine?
► Does the infant lift the head and shoulder girdle up off the support surface and take weight on the forearms?
► If the infant is positioned supporting on the forearms, does she maintain the position for a few seconds at least?
► Does the infant push up on the UEs, taking weight on the hands and extending the elbows, even briefly?
Posture and abilities lying on a caregiver's chest
Let the caregiver lie with the back supported at about a 20-45 degree angle. Let the infant lie prone on the caregiver's chest. Move the infant's hands to shoulder or head height.
► Does the infant like/tolerate this position?
► Does she push down on her hands and lift her head and shoulders?
► Is head lifting associated with thoracic extension?
Posture and abilities when carried upright facing a caregiver's chest.
Infant's are often carried upright, either supported by the caregiver's hands or by a sling. The amount of support needed by the infant's decreases as the infant's trunk stability and postural control improve with age and experience.
► The infant's trunk and head posture and level of activity. Note the position of the upper and lower extremities.
► The amount of support provided by the caregiver: full support around the chest, or light support around the chest.
► Does the infant lift the head to look at the caregiver? Does the infant turn the head to look around?
Posture and abilities lying over a rolled up blanket
Infants who do not like lying on a a flat surface, will sometimes tolerate prone when supported under the chest so that the head and shoulders are lifted up off the surface and it is easier to keep the head up and use the UEs for support.
I like to use a rolled up fleece blanket - it is soft and the roll can be bent to provide some lateral support.
► Ability to maintain neck and trunk extension with some weight on the forearms.
► Position of the head - in line with the trunk or with face at 450 angle.
► Ability to lift one hand and reach for a toy with extended elbows?
Assessment at 7 - 12 months
By 7 months typically developing infants have usually learned to roll from supine to prone and are more willing to spend more time in prone. They have become active in prone, supporting on their UE when reaching for toys, pivoting around in a circle, pushing up into prone kneeling and eventually crawling.
To start your assessment let the infant lie in prone on a firm flat supporting surface. Provide toys that are interesting to watch or reach for, as well as opportunities for social interaction. Observe whether the infant has developed each of the expected abilities.
Prone prop position
► Does the infant assume a position supporting on the forearms some of the time?
► Are the hips extended with some abduction. Or are the hips flexed?
► Is the infant able to shift weight onto one UE and reach for a toy?
Infant pushes up on hands with extended elbows
► Does the infant push up on the hands and lift the head and shoulders up off the support surface?
► Does the infant lock the elbows into hyperextension?
► Does the associated trunk extension include the lumbar spine?
► Are the hips extended or flexed abducted.
Infant assumes prone pivot (swimming) position
► Does the infant abduct the shoulders, extend the thoracic and lumbar spine and lift the torso and the thighs off the support surface (6-7 month pattern)?
► Or does the infant only partially lift the head and shoulder up off the support surface with extension of the thoracic but not lumbar spine (5-6 month pattern)?
Does the infant achieve a partial prone pivot position - with the head and UEs lifted up off the support surface, but not the upper torso?
Posture and abilities lying with torso on a step
Let the infant lie prone with the chest supported on a low foam block, about 10 cm high.
Infant who do not tolerate lying prone on a flat surface will often be willing to lie with the chest supported on a low step. The position may be more comfortable because the hips are in a more flexed position.
► Observe the infant's trunk and LE posture. Is the posture posture symmetrical?
► Are the hips abducted, extended or flexed?
► Does the infant tolerate the position for at least a few minutes?
► Does the infant push down on the hands or forearms and lift the head?
► Does the infant push up either on the forearms or the hands.
► Does the infant lift the head and shoulders up off the support surface?
Moving around on the floor
Infants who have well developed extension of the spine, along with the ability to use the UEs for support will usually start to reach for toys and pivot on the spot as they become more mobile.
Start by encouraging the infant to lie prone on a firm non-slip surface. Follow up by placing the infant on a smooth surface that is relatively slippery. Place toys just out of reach to encourage the infant to work at getting to the toy.
Observe whether the following actions are present.
► Does the infant pivot around on the spot to reach for a toy to the side?
► Does the infant attempt to pull herself forwards using the arms and pushing with the feet? This action may be symmetrical or asymmetrical.
Does the infant move forwards by lifting the chest up off the support surface, extending the shoulders and then falling forwards?
Some infants move across the floor by rolling.
Pushing back on extended UEs
The infant pushes up on the hands, lifts the head and torso and slides backwards.
Playing in side lying
► Infant twists onto the side and maintains position while playing with a toy. This position requires good balance responses as well as trunk muscle strength.
Some thoughts about crawling
A series of blog posts in response to Mindy Silva's question: Why do infants "bunny hop"?
About the neonate to crawling series
Variability, learning to balance in prone kneeling and early crawling
What abilities are needed for reciprocal crawling?
Infants who "bunny hop" need to acquire more varied patterns of movement
Prone kneeling: strength, coordination, stability and balance requirements