Reasons why babies neglect one arm and hand
There are two main reasons why an infant has difficulties with moving one arm. The first is Erb's Palsy, an injury to the nerves going to the arm that occurs during birth. Because the baby does not move the arm at all, the injury is usually picked up early and the baby is referred to a specialist doctor for assessment and referral to physical therapy. Read more
The other reason for weakness and neglect of one arm is a disturbance in the developing brain, either before or at birth. A disturbance in development of the brain may be associated with preterm birth. Full term infants may suffer a perinatal stroke before or just after birth. A perinatal stroke causes weakness in the arm and leg on the one side, and is often missed because the signs and symptoms may be very subtle in the very young baby, but become more prominent over time, Read more
Knowing how babies move their arms is the first step to recognizing possible neglect.
If you notice that your baby is not using the one hand in the same way as the other one, it is a good idea to take some time to observe how your baby uses her/his hands for different activities.
Then, if you still have concerns that your baby is neglecting the one hand, and the abilities of one does not match those of the other hand, it is a good idea to ask your child's primary health care professional to assess your baby's motor development and make a referral to a pediatrician or early intervention occupational or physical therapist for a full assessment.
Observing your baby to identify weakness and neglect
Very young babies mostly move one arm at time, but will move both arms. From about 3 months babies start to move the arms at the same time, reaching with both hands for toys.
Very young babies: 1-2 months
At this age babies often lie with their heads turned to one side, with one arm straight and the other one bent. Most babies have a preferred side for turning the head.
In this position the baby will often spend time looking at her hand with great interest.
Very young babies, when they are awake and alert, will engage in bouts of vigorous moving of the arms and the legs. The amount and pattern of the movements are the similar for the right and the left arm and leg.
If you hang a toys within easy reach, young babies will start to make swiping movements of the arm in the direction of the toy.
At this age babies tend to hold their hands lightly fisted with the thumb next to the index finger most of the time. But they will also open and close the fingers, and will move the fingers separately, pointing with one finger or bringing the tip of the thumb and forefinger together.
Observing your baby
Take time to observe your baby when she is awake, alert and happy. Let her lie on a firm flat surface and observe her movements. If she is not very active, talk to her to raise her level of arousal to get her moving.
Notice whether she is moving the right arm and leg the same amount and in the same way as the left arm and leg.
Also watch the movements of her fingers. Does she sometimes stretch her fingers and keep the thumbs next to the forefinger.
Babies from 3-6 months
At this age babies have learned to lie with their heads straight and bring their hands together in the midline above the face where they are a good position for easy, intense visual inspection.
Babies like to feel one hand with the other using complex finger movements and will watch these actions with great interest.
In this position babies will start to hold a toy with one hand and use the fingers of the other hand to inspect the toy.
They also use their hands and fingers to explore any surface they touch including clothing and their own bodies.
At 3 months babies will keep holding a toy that is placed in the hand for a short period of time. By 4 months babies will hold the toy and take time to look at it carefully. .
At this age babies will usually reach for a toy that is presented in within easy reaching distance, with both hands.
Observing your infant at 3-6 months
Let your infant lie on a firm flat surface.
► Talk to her so that she becomes a little excited and watch her arm movements to see if she moves both arms in the same way.
► Also watch her finger movement. Does she open and close her fingers and move the fingers separately? When the hand is fisted, is the thumb next to her forefinger or tucked across the palm?
► Hold a toy that she can grasp easily, within easy reaching distance. Does she reach for the toy with both hands?
► Another good way to observe your baby using her hands is to suspend one or two toys from play gym and watch her reaching for and playing with the toys. Does he look at the toys with great interest? ? Does he reach up for a toy with both hands? Is he able to grasp the toy with one or both hands? Does she use his fingers to play with the toy. See How to set up an infant play gym
► You can also let you infant sit in a reclined seat which has a bar where you can attach one or two toys.
Babies 7-8 months and older
From 7-8 months typically developing babies have started to use their arms to move around on their tummies by scooting backwards, commando crawling and getting up onto all fours.
Babies with weakness in the one arm find it difficult to push up into the crawling position and will often opt for commando crawling using the stronger arm to propel themselves forwards.
At 7 months typically developing babies can usually sit independently. Infants born preterm may sit a month or two later even using corrected age.
Once they have good balance in sitting their hands are free to pick up and manipulate interesting objects and at this age they become very interested, even obsessional about exploring what can be done with different toys.
Actions such as shaking, banging, throwing, and posting objects can be done with one hand.
But many actions need two hands: catching a ball, picking up large toys, tipping a container upside down, pulling apart and putting together.
Suggestions for observing your baby
The best way to observe how well your baby is using both the hands is to give her the opportunity to play with a selection of toys to pick up and manipulate.
Let your baby sit on the floor or in a feeding chair. If her balance in sitting is not good you can provide some support around the hips.
The best way to get you baby engrossed in playing is to provide some new toys. Everyday objects that you can find in your home provide an endless source of new "toys".
Here are just a few suggestions everyday objects that infants like to play with. For more ideas see: My favorite toys can all be found in the home
Big bottles for lifting and moving
Metal jar lids for posting and packing in and out of containers.
Cardboard boxes of different sizes
New video blog: How to use everyday objects to create activities
What to do if you notice that your infant is not using one hand well
If you are concerned that your baby is not using one hand as much as the other, it is a good idea to ask your baby's health care provider to take a careful look at the next clinic visit. Ask for a referral to an occupational or physical therapist for an assessment. Doctors often take a "wait and see" approach to developmental delay which is a pity because research shows that early intervention is the best way to overcome the movement difficulties that babies experience if brain development has been disturbed in any way. In fact it is a matter of the earlier the better. (See Early intervention after perinatal stroke: opportunities and challenges.)
In the meantime
While you are waiting for an appointment to see a physical or occupational therapist, or if you do not have access to these services, you can start to promote your babies hand function by providing him with many different opportunities to encourage using the hands separately or together.
For infants up to 6-7 months
And those who are not yet sitting, a play gym is a very good investment. See also How to set up your play gym
For infants who are sitting
What infants learn to do once they can sit
Baby Hands - tracking development and activities
McIntyre S, Morgan C,Walker K, Novak I. Cerebral palsy –don’t delay.(2011) Developmental Disabilities Research Reviews. 17(2): 114-129.
Basu A. P. (2014). Early intervention after perinatal stroke: opportunities and challenges. Developmental medicine and child neurology, 56(6), 516-21.
Hoare B, Greaves S. (2017) Unimanual versus bimanual therapy in children with unilateral cerebral palsy: Same, same, but different. J Pediatr Rehabil Med. 2017;10(1):47-59.
Greaves S, Imms C, Krumlinde-Sundholm L, Dodd K, Eliasson AC. (2012) Bimanual behaviours in children aged 8-18 months: a literature review to select toys that elicit the use of two hands. Res Dev Disabil. Jan-Feb;33(1):240-50.