1-2 month period (4-12 weeks)

Infant Perceptual-Motor Development

1-2 months (4-12 weeks) period

Pam Versfeld December 2018

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Overview

  • During the 1-2 month period the infant is awake and alert for longer periods of time, increasingly responds to sounds and sights from the environment and gains more control of movements of the head and limbs
  • Head control in supine is improving as the infant learns to hold the head steady in the midline as well as turn the head to locate interesting sights and sounds.
  • When held upright infants can keep the head erect for extended periods of time.
  • Neck rotation is still associated with extension and lateral flexion.
  • Spontaneous movements of the lower extremities, along with the pull of gravity serve to stretch the hip and knee flexor muscles, leading to increased range of extension of the extremity joints.
  • Postural control of the trunk is improving but movement of the extremities still leads to lateral displacement and sometimes rotation of the pelvis.
  • Vigorous kicking of the LEs is often associated with abduction of the shoulders and extension of the elbows as the infant works to maintain a steady torso.
  • Kicking movements still show strong coupling between the hip and knee joints, however the ability to uncouple hip and knee emerges when the infant engages in goal directed actions of the foot, such as reaching to a target with the foot.
  • Whole body general movements give way to fidgety general movements from around 9 weeks.
  • Infants start to reach successfully towards interesting object within reach and start to use finger movements to explore objects.
  • Infants actively explore surfaces with their feet and hands.
  • Although simultaneous flexion and extension movements of the fingers are still common, independent movements of the fingers become more prominent.

General and fidgety movements

General movements continue to be characterized by writhing movements that involve the head, trunk and extremities in the 1-2 month period. However, towards the end of this period fidgety movements (FMs) are increasingly present (Einspieler 2016)

Writhing general movements in a healthy full term infant are described as complex and involve the entire body, notably arm, leg, neck, and trunk movements in  variable sequences. They wax and wane, varying in intensity, speed, and range of motion, and have a gradual onset and end.

Rotations around the limb axes and slight changes in the direction of movement create the impression of fluency and elegance.

FMs are small movements of moderate speed with variable acceleration of the neck, trunk, and limbs in all directions. They may appear as early as six weeks after term, but usually occur from around 9 weeks until 16–20 weeks, occasionally even a few weeks longer. They fade out when antigravity and intentional movements start to dominate.

The presence and character of fidgety movements are good indicators of the integrity of the infants nervous system (Einspieler 2016).

Head control and neck movements

At the beginning of the 1-2 month period the infant still tends to lie supine with the head turned to one or the other side. Head rotation continues to be associated with some neck extension and lateral flexion.

Head turning may be associated with an asymmetrical tonic neck reflex (ATNR) posture, but this is not obligatory.

W 5w vigourance movement 7.jpg       Will 7w supine repose momennts 3.jpg

By the end of the 1-2 month period the infant is more inclined to hold the head in the midline and easily turns the head to look at interesting objects and events in the environment.

Will 7w supine repose momennts 4.jpg

At this age infants tend to lie with the UEs abducted and extended, a position that helps to stabilize the trunk and provide a stable base for head movements and kicking (Bly 1994).

Will 10w following dangled toy 1.jpg      Will 10w following dangled toy 3.jpg    

The infant is also able to combine neck rotation with extension of the head to look upwards. 

However, control of the exact position of the head is clearly still developing, as rotation is usually associated with some neck extension and lateral flexion. This combination of movements suggests that the movement is brought about by contraction of the sternocleidomastoid muscles, with limited action in the deep neck stabilizers (Bly 1994).

Will 10w supine repose momennts 6.jpg

The 1-2 month old infant is able to visually follow an object from the side to the midline, as well as follow an object moved in a downwards direction. The ability to follow an object across the midline is not present yet.

Will 10w following dangled toy 1.jpg    Will 10w following dangled toy 2.jpg    Will 10 w hip extension.jpg

Upper extremity actions

During periods of relative quiet the one-month-old infant adopts a variety of postures of the upper extremities. Abduction of the shoulders with the upper arms resting on the support surface is often observed – in this position the UEs serve as outriggers and help to stabilize the trunk when moving the head and lower extremities. Interestingly this co-opting of the UEs for a postural function during this period is associated with a decrease in the occurrence of swiping actions of the UEs towards objects within reach (von Hofsten 1984).

Head rotation may be associated with the fencing position (extension of the face elbow with flexion of the skull elbow). However this association decreases over the 1-2 month period, and importantly, is never obligatory.

Will 10w supine repose momennts 3.jpg    Will 10w supine repose momennts 5.jpg   Will 10w supine repose momennts 6_1.jpg

The tendency to abduct the shoulders and use the UEs as outriggers decreases towards the end of this period when infants start to bring their hands into the midline. 

Will 10w in nest 1.jpg   W 15w explore soft cloth.jpg

At the beginning of the 1-2 month period infants produce large range swiping movements of the upper extremities. These swiping movements are associated with elbow extension and extension of the fingers. The hand comes close to the object, but mostly does not make contact.

Over the coming weeks the infant gains more control over reaching movements and starts to reach towards objects within easy reach with greater success. The extension of the fingers seen in the one month old infant become less pronounced (Hofsten 1984).

W 5w swipe 1.jpg   W 5w swipe 6.jpg   W 5w swipe 3.jpg

Towards the end of this period (10-12 weeks), as the infant's ability to steady the head and trunk when moving the UEs becomes more reliable the infant gains more control of reaching towards toys. They are able to bring the hand into contact with the toy and start to use the fingers to explore it.

This is the start of the ability to stabilise the position of the hand in space and at the same time use independent finger movements to gather information about the texture, structure and behaviour of objects. Visual attention to the toy and the hand provides further information that starts to link what is felt and seen.

W 8w reach in bouncy chair.jpg    W 12w hand contact toy.jpg

Exploratory hand movements

During this period infants continue to use their hands to gather information about the surfaces they encounter. Contact with a surface is often associated with exploratory movements of the hand across the surface, or repeated flexion and extension of the fingers.

 

Independent movements of the fingers are also frequently seen, especially when the infant is socially engaged or is paying attention to an object within reaching distance.

Postural sway and postural stability

Observing an infant during periods of quiet supine lying allows one to observe the postural sway present in the trunk. These exploratory movements allow the postural system to gather the sensory information needed for estimating the position of the body as a whole and exploring the most effective strategies to maintain a stable posture (Dusing 2013).

Here you see Will lying quietly at 5 and 10 weeks of age. The upper arms come to rest on the SS and the continuous lateral sway of the trunk provides changing contact between the upper arm and the SS.

Will is also exploring the contact between his feet and the SS, and between each other. This exploration is important for developing the infant's ability to use surfaces to support their actions.

W 5w quiet moment 1.jpg   Will 7w supine repose momennts 4.jpg

Lower extremity movements

The 1-2 month old infant engages in periods of relative calm when the feet rest on the SS with varying amounts of flexion of the hips and knees.

At 7 weeks Will's range of hip and knee extension is still restricted by the remaining physiological flexor stiffness.

Will 7w supine repose momennts 3_2.jpg      Will 7w supine repose momennts 1.jpg

By 10 weeks Will has close to full range of hip and knee extension. Full hip extension is associated with anterior pelvic tilt. The range of ankle plantar flexion has also increased.

Will 10 w hip extension_1.jpg

The 1-2 month old still engages in extended periods of kicking. Movement patterns include repeated single leg kicking with alternate leg kicking and bilateral hip and knee flexion and extension.

At this age hip and knee movements are still coupled. The ankles remain in dorsiflexion with intermittent flexion and extension of the toes.

W 5w vigourance movement 11.jpg   W 5w vigourance movement 12.jpg   

The range of movement of hip flexion and knee extension during kicking movements increases over the 1-2 month period, as seen in these pictures of Will at 10 weeks.

Will 10w kicking 1.jpg   Will 10w kicking 2.jpg   Will 10w kicking 3.jpg   Will 10w kicking 4.jpg   Will 10w kicking 5.jpg   Will 10w kicking 6.jpg

LE Bridging

From time to time one or both feet push down on the SS. Pushing down with one foot is associated with head and trunk extension and lateral weight shift.

W 5w vigourance movement 3.jpg   

Foot reaching

Although spontaneous kicking actions tend to still show strong intra-limb coupling, research has shown that 2 month old infants can adapt their LE actions to operate a mobile and make contact with a toy that has been suspended in the midline.

Pull-to-sit

The infant's response to the pull-to-sit maneuver is often used as a test when assessing motor development. It provides a good measure of the infant's neck muscle strength as well as the development of effective anticipatory postural responses.

The newborn, when pulled to sit, the head lags behind the body, but does not fall back fully. Once the trunk is erect, the infant will lift the head in line with the trunk.

By the end of the 1-2 month period, infants have learned to anticipate being lifted and will participate in the PTS maneuver by engaging the neck and trunk flexor muscles, stiffening the UEs and flexing the hips.

The head is held in line with the trunk as the shoulders are lifted.

Will 10w pull sit 1.jpg   Will 10w pull sit 2.jpg   Will 10w PTS 2.jpg

Once in the upright position the head is held erect, and the infant is able to lift the face to look at the person who has pulled him into sitting.

Will 10w PTS 3.jpg   Will 10w PTS 4.jpg

 

Sitting

Bly (1994) describes the characteristics of sitting at the beginning of the 1-2 month period as follows:

  • In supported sitting the head falls forwards although the infant does make brief attempts to hold it up.
  • The infant's UEs no longer hang loosely at the infant's side.
  • During brief periods of lifting the head there is retraction of the scapulae, increased flexion of the elbows, forearm pronation, extension of the wrist and flexion of the finger.
  • Bly surmises that the the retraction of the scapulae may provide synergistic stability for head lifting.
  • The hips are flexed, abducted and laterally rotated, the knees more flexed than in the neonatal period, and the ankles are strongly dorsiflexed and everted as in the neonatal period.

will 4w sitting 2.jpg    will 4w sitting 3.jpg

At 6 weeks Will is able to extend the head and thoracic spine when supported around the waist, but still flops forwards when supported at the pelvis.

will 6w sitting.jpg    will 6w sitting 1.jpg

Over the 1-2 month period the infants gain increasing control of the position of the trunk when they sit with support around the hips.

They are able to maintain the trunk in a semi-erect position, with the line of gravity falling anterior the the flexion-extension axis of the hips, creating a gravity flexion moment at the hips which is counteracted by the hips extensors. The trunk and neck extensors work to maintain some extension in the trunk.

Will 10w sitting pelvic support 1.jpg    Will 10w sitting pelvic support 2.jpg

The ability to to control the position of the trunk is less well developed when the trunk is tilted backwards so that the LOG falls posterior to the flexion/extension axis of the hips,

Notice how this rapid backwards movement initiates a response in the trunk and neck flexors, as well as reactions in his upper limbs as the postural system responds to the rapid backwards movement of the head.

Will 10w sitting pelvic support 3.jpg    Will 10w sitting with support 6.jpg

Response to being picked up and moved

By the end of the 1-2 month period infants have started to anticipate being picked up and moved. They are able to hold the head in line with the trunk when supported around the chest, especially when tipped forwards or laterally.

Will 10w being lifted 2.jpg    Will 10w being lifted 1.jpg

Prone

Back to sleep advice. In the past many infants were put into prone for sleeping, but more recently because prone sleeping is a risk factor for sudden infant death, parents are advised to let infants sleep on their backs. As a result many infants do not like being placed in prone, quickly start to cry and also quickly learn to roll from prone to supine.

At the beginning of the 1-2 month period, infants start to lift the head up off the support surface (SS) for brief periods of time. This is accomplished by the neck and thoracic extensor muscle activity.

Will 5w changes in position 10.jpg

When in prone infants engage in active kicking, alternating between unilateral and bilateral hip and knee flexion and extension. The ankles remain dorsiflexed, with the range of dorsiflexion (DF) increasing with full hip and knee flexion and decreasing with hip and knee extension.

Unilateral kicking movements are associated with lateral flexion of the trunk with a lateral shift in weight bearing.

Bilateral hip and knee flexion is associated with anterior pelvic tilt and a cephalad shift of weight onto the upper torso.

Will 5w changes in position 12.jpg   Will 5w changes in position 13.jpgWill 5w changes in position 15.jpg   Will 5w changes in position 16.jpg

Rolling from prone to supine

Will's ability to initiate rolling from prone to supine illustrate how by 5 weeks he has learned to exploit his rapidly developing control of movement of the extremities to initiate a sequence of movements directed towards achieving a goal.

After a period of kicking, Will decides that he has had enough of being in prone, and initiates rolling to supine by lifting his head and extending the thoracic spine. These movements are associated with a more extended position of the hips and knees bilaterally and a shift of his COM caudally.

He rotates his shoulder girdle back on the right, flexes the right hip then "falls" onto his back.

Will 5w prone lift head 13.jpg   Will 5w prone lift head 15.jpg   Will 5w prone lift head 16.jpg

I turn Will back into prone, and he immediately rolls back into supine, this time using a slightly different pattern of movement. He pushes down on his right hand, extends his elbow, and extends the thoracic spine. The COM shifts caudally, but there is no associated extension of the hips. Will collapses onto his left side with the hips still in flexion, and then rolls onto his back.

Will 5w prone roll over 12.jpg   Will 5w prone roll over 13.jpg   

Will 5w prone roll over 14.jpg

By the end of the 1-2 month period, the infant's ability to lift the head and extend the thoracic spine has improved. This is associated with taking some weight on the hands. 

Extension of the neck and thoracic spine is now associated with extension and adduction of the hips.

W 12w prone 11.jpg   W 12w prone 12.jpg

Will 10w prone 6.jpg

The ROM of extension at the hips and knees has increased. Some of the time flexion of the knee is associated with flexion of the hip, but not always. This is the beginning of uncoupling the of hip and knee flexion and the beginning of the ability to dissociate movements of the two joints.

Will 10w prone forearm support 4.jpg   Will 10w prone forearm support 6.jpg   Will 10w prone forearm support 8.jpg   Will 10w prone forearm support 5.jpg


References and bibliography

Adolph, K.E. and Kretch, K.S. (2015) Gibson’s Theory of Perceptual Learning. International Encyclopedia of the Social & Behavioral Sciences, Second Edition

Bly L. (1994) Motor Skills Acquisition in the First Year.  

Corbetta, D., Dimercurio, A., Wiener, R. F., Connell, J. P., & Clark, M. (2018). How Perception and Action Fosters Exploration and Selection in Infant Skill Acquisition. Advances in Child Development and Behavior (Vol. 55, pp. 1–29). Elsevier Ltd.

Cornwell, K. S., Fitzgerald, H. E., & Harris, L. J. (1985). On the state‐dependent nature of infant head orientation. Infant Mental Health Journal, 6(3), 137-144.

Duncan K, Goodworth A, Da Costa CSN, Wininger M, Saavedra S. (2017) Parent handling of typical infants varies segmentally across development of postural control. Exp Brain Res. 236(3):645-654.

Einspieler, C., Marschik, P. B., & Prechtl, H. F. R. (2008). Human Motor Behavior Prenatal Origin and Early Postnatal Development. Journal of Psychology, 216(3) 148–154.

Lee HM, Galloway JC. (20120 Early intensive postural and movement training advances head control in very young infants. Phys Ther. Jul;92(7):935-47.

Lima-Alvarez CD, Tudella E, van der Kamp J, Savelsbergh GJ. (2013) Effects of postural manipulations on head movements from birth to 4 months of age. J Mot Behav. 45(3):195-203.

Lima-Alvarez CD, Tudella E, van der Kamp J, Savelsbergh GJ. (2014) Early development of head movements between birth and 4 months of age: a longitudinal study. J Mot Behav. 46(6):415-22. 

Reddy, V., Markova, G., & Wallot, S. (2013). Anticipatory Adjustments to Being Picked Up in Infancy. PLoS ONE, 8(6), https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3688725/

von Hofsten C, Rönnqvist L. (1993) The structuring of neonatal arm movements. Child Dev. 64(4):1046-57.  PDF

von Hofsten C, Rönnqvist L.(1993) The structuring of neonatal arm movements. Child Dev. ;64(4):1046-57.  PDF

von Hofsten C, Rosander K. (2018) The Development of Sensorimotor Intelligence in Infants. Adv Child Dev Behav. 2018;55:73-106.

Von Hoften, C, Ronquis L. (1994) Neonatal finger and arm movements as determined by a social context.  Early Development and Parenting . 3(2), 81-94

Hofsten, C. Von. (1984). Developmental Changes in the Organization of Pre-reaching Movements. Developmental Psychology 20(3), 378–388.