Hypotonia: one word, one label but one size does NOT fit all.
Hypotonia is a word that is frequently bandied about in conjunction with a diagnosis of Down Syndrome as well as a lot of other developmental disabilities stemming from chromosomal duplication or depletion syndromes. As much as this is a common feature of these syndromes, physical presentations of the children with ‘hypotonia’ is far from common and is as unique to each individual child as their fingerprints.
If we break down the meaning of the word and look at what it actually means:
- Hypo = low
- Tonia (tone) = the normal degree of vigor and tension; in muscle the resistance to passive elongation or stretch (https://medical-dictionary.thefreedictionary.com/tone)
Therefore – it implies that it is muscle that has limited resistance to stretch or is able to stretch easily. This is also referred to and commonly known in the neurotypically developing world as ‘the floppy child.’ Parents of a child with a disability have all heard this term and thought
- What does that mean?
- What does that mean for MY child
- How will it affect THEIR development?
Very good questions and unfortunately, the regardless of diagnosis and the commonality of having hypotonia or floppy limbs, the answers to the questions depend on a multitude of other factors all as individual and unique as your child.
Muscle tone is a sliding scale from HYPOtonia to HYPERtonia and we all fit into that sliding scale somewhere. We all have that friend who looks at a weight or eats a hard-boiled egg and puts on muscle... likewise we all have that friend who swears they lift weights, exercise 7x week and don’t gain any muscle definition or bulk. It’s all genetics and the balance of where we sit on the spectrum of muscle tone. Often this is balanced out by our joints and the degree of joint laxity (looseness.) Some people have zero muscle tone but their joints are hypomobile therefore the body balances itself out. Other people have high muscle tone and very loose joints also resulting in the body balancing itself out. Depending on where we fit onto this spectrum of hypo / hypertonia as well as hyper/hypomobility will have a significant impact on how our body moves and how much work we need to do to control it.
Commonly, children with a diagnosis of hypotonia will also have a diagnosis of hypermobility. This results in a muscle which has limited resistance (if any) to stretch trying to control joints that have too much movement… just slightly problematic!! Other factors which will affect how your child develops and the degree which hypotonia will affect them include:
- Size and weight of your child,
- Infant head circumference (hydrocephaly, macrocephaly or microcephaly)
- Degree of prematurity,
- Open heart surgery or other early medical interventions limiting the positions they can be placed in.
This is just to name a few but I’m sure reading between the lines you’ve got the idea that it is basically anything and everything that is going on with your child in their first few months of life has the potential to impact their development in conjunction with the hypotonia … hence the importance of early intervention!
To make things extra complicated, long muscles are weak muscles; meaning you have a weak muscle trying to control a joint that has too much movement. HARD! As your child grows, their body weight, limb length and weight get bigger, heavier and longer. Therefore, you have an already weak muscle trying to control a joint that has too much movement as it gets heavier, bigger and harder to control, while the muscles lengthening and continuing to get weaker… HARDER! And as your child keeps growing, this vicious circle continues. HARDER AND HARDER!!
DON’T WORRY, it’s not all negative! The bonus is, children eventually stop growing!! So the bones stop getting longer and heavier, the muscles get stronger and learn to control those joints with extra movement and the VICIOUS CYCLE IS BROKEN! Movements get more efficient so the muscles don’t have to work as hard and eventually your child won’t get as fatigued. Treatment strategies such as Theratogs, taping and compression garments aim to limit the impact of the hypotonia and hypermobility and assist your child to work towards developing their milestones however there is absolutely no denying it is still hard work for all involved.