Developmental Delay and Hypotonia

Sometimes children will be referred to us for Developmental Delay or Hypotonia where the parent and/or the pediatrician notices that the child is late in attaining the motor milestones suggested by the standardized norms. Often there is not another diagnosis that would explain why the child is progressing slowly. Parents are often and understandably confused as to the difference between Developmental Delay and Hypotonia. While Hypotonia frequently results in developmental delay, it is not necessarily the cause of all developmental delay. Here we will discuss developmental delay due to the most common cause, hypotonia.

WHAT IS DEVELOPMENTAL DELAY?

Developmental Delay simply describes a child who does meet gross motor milestones at the expected times. This description, however, does not target the root cause of the problem. Sometimes a more specific diagnosis such as hypotonia is apparent or becomes more obvious as the child grows. More often though, no other specific diagnosis is warranted .
When motor skills emerge during infancy. (Touwen,1976)
Roll supine to prone 3 – 6 months
Roll prone to supine 3 – 8 months
Belly crawl 4.5 – 10 months
Independent sit 6 – 11 months
Attaining sit 6 – 12.5 months
Crawl (hands/knees) 7 – 13 months
Walk with help 8 – 15 months
Stand independently 8 – 18 months
Walk independently 10 – 20 months

WHAT IS HYPOTONIA?

Hypotonia is “a medical term used to describe decreased muscle tone (the amount of resistance to movement in a muscle). It is not the same as muscle weakness, although the two conditions can co-exist…Infants with hypotonia have a floppy quality or “rag doll” appearance…Other symptoms of hypotonia include problems with mobility and posture, breathing and speech difficulties, lethargy, ligament and joint laxity, and poor reflexes. Hypotonia does not affect intellect…” according to the National Institute of Health (NIH).
This definition is exciting because it states that hypotonia is NOT the same as muscle weakness. It talks about muscle “tone” which is more about the quality of a muscle rather than its ability and function. The difference between high tone and low tone is something that you can feel but not necessarily quantify. Have you ever picked up a toddler and it feels like you are picking up a robot or a ton of bricks? They sit on your hip sort of rigidly. That is a high (normal but high) tone child. Have you picked up another child that feels like they will slip through your hands? He or she snuggles right into your body perfectly. That is a low tone child (often normal but low). Understanding muscle tone will help you understand the treatment for developmental delay when related to hypotonia.

HOW DO CHILDREN WITH DEVELOPMENTAL DELAY OR HYPOTONIA ACT?

Some of the children with low tone like to sit and observe rather than get in the mix of things. Typically they sit with a rounded back but sometimes they will sit nice and straight but tend to remain in that position. They will be content with whatever toys are close by and often will not move toward a more distant toy. In fact, if you dangle that toy or show them how to operate the toy they will be interested as long as you make the toy work!! When you stop, however, they wait for you to do more. If you stop long enough they will go back to playing with whatever is nearby, or to doing nothing. As the child grows and begins to develop more cognitively the child often begins to reach out further into its environment. A child without Developmental Delay or Hypotonia will often experiment with moving gradually in many directions. A child with hypotonia will often develop one way of moving and then slowly add new ways, but only if the old movement is repeatedly not working for them. For example a child that is developing typically will sit in a variety of ways while playing. They will ring sit, sit with legs straight, or sit with one leg bent and the other straight. A child with hypotonia will typically ring sit only and not try any other methods.

CAN YOU HELP A CHILD WITH HYPOTONIA?

ABSOLUTELY!! Most of the rehabilitative therapies will help a child attain the motor milestones. The earlier you address the symptoms, the sooner the child will begin to develop the milestones. So, early intervention is the key.
Barbara Hypes, PT has developed a special interest in treating children with hypotonia. It is her belief that children with this diagnosis need time to process what they feel and time to come up with a motor plan. Typically children with hypotonia want to wait before entering play. This could be because they are processing what it will require to move – taking into consideration what they see, feel, hear, perceive and how to move their body in response to all of that information . So as therapists and parents working with children with hypotonia waiting is going to be a key component.
One must wait for specific actions and react in the appropriate way. A child with this diagnosis reacts usually slowly to a stimulus but if the child is in a new or awkward position this information will take precedence over the other information coming in and cause the child to react. Showing the child typical ways of transitioning and moving, and then stopping the process midstream, will allow them to feel the beginning of the movement and develop the most likely next step to complete it. A child with hypotonia needs time at this point to process what she or he has felt and is continuing to feel so it is important to wait at this point. The issue might be walking steps but it could also be moving from sitting to lying on the belly. Often the child will express his or her frustration because not only is the child growing impatient but it is not sure what motor plan to use to fix the problem. Sometimes the child is afraid of the new position because it feels so different. Giving the child time to figure this out allows it to incorporate the movement into his or her motor planning and to use it again. Gradually, the child will use it as a general movement.
Knowing typical movements and how to activate the correct muscles is key in helping these kids begin to move. A physical therapist will teach you how to facilitate movement and where to stop, where to hold the child so he or she is successful in completing a movement, and how to know which movements are important at each developmental stage.
One enlightening example involved a little girl, Trina, who was 7 months old. She could sit and bang and mouth toys but only those that she could reach by leaning forward over her legs (a very safe maneuver). Trina did not like to stand up very much and she also did not like to be on her belly at all. During one session the therapist began to work just on standing up. The therapist got Trina’s feet into a nice stable position and then assisted her in standing by holding at her waist. Trina took the weight in her legs but bent over at her hips like she was touching her toes. At first the therapist thought, “This makes sense, Trina is just not sure what I am asking her to do” so she showed her again. Well Trina thought, “Hey she wants me to lean on her hand while she moves me up.” So Trina (did the same thing) bent over at her hips again. Well, she did not know what the therapist wanted. So the third time, the therapist let her stay in her toe touching position for probably 7 seconds and, lo and behold, Trina began to raise her trunk into a mostly erect standing position. The therapist immediately let her sit back down and everyone present clapped. Now Trina knew what to do, right? Well, sort of. On the next try she repeated the same thing – flexing forward, needing extra time, but she stood again. After about 4 more attempts she did not flex forward when she accepted the weight through her legs and even stood erectly and took a toy from her mom’s hand. Within a week she knew that when she felt weight on her feet she should stand up tall. Not many 7 month olds walk but they do work on standing, and the therapist prepared her to establish new motor plans, how to do them while standing, and how to begin to generalize them to new situations (like reaching while standing).
Children with hypotonia need time to get motor plans together. Facilitating this process as early as possible might make a huge difference in how a child begins to process the world in all areas, gross motor, fine motor, cognitive, and emotional. What is fantastic about children with hypotonia is that they become very pleased with themselves and their new accomplishments once they can incorporate them into their motor plan.
Motor plans are a person’s ability to think through and physically carry out a task. The Journal of Pediatric Physical Therapy published an article on variation and variability of movements as it relates to normal development. The basic theory in the article is that normal movement varies constantly. Therefore, the more variable the movements a child uses during its motor development the more likely it will be that a child uses normal patterns for movement. When a child with a repertoire of variable movement patterns encounters an obstacle, if she has variability, she or he is able to use another pattern to maneuver around the obstacle. A child responds to its environment every time it moves. Children also respond to their own bodies every time they move.
If you think about the endless possible combinations, you would conclude that a child might need to make anywhere from a slight adjustment to a major adjustment to their motor plan every time they roll for a toy or take a few steps. Maybe it is cold one time so they have to roll when they shiver. Or maybe they are walking from a wood floor to a carpet floor. Maybe they are now holding a toy when they want to roll or walk. Maybe their pants shifted slightly causing a new feeling on their leg, and maybe that caused them to try a new pattern even if one wasn’t necessary. Having a large repertoire of movement patterns and the ability to vary them is the key to normal movement. Children with hypotonia often need help developing motor plans and choosing motor plans for each scenario. A pediatric physical therapist can help facilitate this process.

How do I know if my child has hypotonia?

• When you pick him up he feels like he might slip through your hands if you don’t hold firmly.
• She tends to be an observer, let’s the world come to her, and is less interested in attacking the world
• He tends to sit with one posture – can be hunched or straight but typically doesn’t vary much
• She tends to lift her feet when you place her on the floor rather than accepting weight on her feet

The more important question is do you need to treat it? The answer is yes if:

• She may not be meeting her developmental milestones
• He tends to have only a few motor plans – like sitting but not reaching far for toys, or rolling but only to one side.
• She seems afraid to try new movements; she appears worried when you try to teach her to accept weight in her hands (wheelbarrow walking).

A good therapist will teach a parent routines that can be worked on at home with the child. These are truly the fun exercises. The parent will be able to watch how much their little one can learn with some time and some “good hands” – that’s pediatric PT talk for knowing where to put your hands to best facilitate the movement.
Written by
Kristin Emery, MPT
http://www.pebblespt.com/physical-therapy-pediatrics-arlington-falls-church-vienna-mclean-alexandria-torticollis-toe-walking-fairfax-annandale-topics-tricks-treatment/developmental-delay-and-hypotonia/