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Hypotonia is a medical term that describes decreased muscle tone.
Healthy muscles are never fully relaxed. They retain a certain amount of tension and stiffness (muscle tone) that can be felt as resistance to movement.
For example, a person relies on the muscle tone in their back and neck to maintain their posture when standing or sitting up. Muscle tone decreases during sleep, so if you fall asleep sitting up you may find that you wake up with your head flopped forward.
Hypotonia is not the same as muscle weakness, although it can still be difficult to use the affected muscles. Depending on the cause, weakness may sometimes develop in association with hypotonia.
Newborn and young children with severe hypotonia are often described as being "floppy" or like a "rag doll". However, as muscle tone develops during pregnancy, premature newborn babies may have decreased muscle tone simply as a result of being premature.
Hypotonia is a symptom that can be a feature of various underlying health conditions, many of which are inherited (passed on from one family member to another).
It can also occur in cases of cerebral palsy, where a number of neurological (brain-related) problems affect a child's co-ordination and movement, and after serious infections such as meningitis (an infection of the outside membrane of the brain).
Read more about the causes of hypotonia.
If hypotonia is suspected, your child will be referred to a specialist paediatrician or neurologist. They will ask you questions about your family history, your pregnancy, delivery any problems that have occurred since birth.
As some conditions that cause hypotonia involve problems with other organs, your child will have some blood tests.
Other tests may also help to diagnose the underlying condition that is causing hypotonia. These could include detailed scans such as a computerised tomography (CT) scan or a magnetic resonance imaging (MRI) scan.
Read more about how hypotonia is diagnosed.
The recommended treatment plan for hypotonia will depend on the underlying cause. Hypotonia is therefore very variable: sometimes improving, sometimes staying the same and sometimes worsening over time.
A baby born prematurely may have hypotonia but it will usually improve as they get older. Babies with hypotonia that is caused by an infection or another condition will usually be cured of it if the condition is successfully treated.
It's often not possible to cure the underlying cause of hypotonia. Where hypotonia is inherited, it will persist throughout a person’s life, but with treatment their ability to function can often be improved. This can involve using physiotherapy, occupational therapy and speech and language therapy.
Someone with hypotonia can also be taught to develop coping strategies, although ongoing support and care may also be needed.
Read more about treating hypotonia.
Hypotonia (decreased muscle tone) is not a condition in itself but a symptom of an underlying condition.
Hypotonia that is present at birth usually becomes noticeable by the time a child is six months old. Signs include:
A child with hypotonia may take longer to reach developmental milestones, such as:
An adult with hypotonia may have the following problems:
To function normally, muscles depend on signals from nerves called motor nerves.
There are two types of hypotonia (decreased muscle tone) that can occur due to problems related to the motor nerves. These are described below.
Nerves are covered by a substance called myelin. Myelin insulates the nerve fibres and helps carry messages to and from your brain quickly and smoothly. If myelin is damaged, the signals do not travel down the nerves normally.
Hypotonia can also occur in disorders that affect the body’s connective tissue, such as Marfan syndrome and Ehlers-Danlos syndrome (see below).
Connective tissue, such as collagen, provides the body’s tissues with strength and support. It is found in ligaments and cartilage.
Some of the many health conditions that can cause hypotonia are described below.
Hypotonia present at birth or shortly after can be caused by:
Read more about genes and chromosomes.
Disorders that cause abnormalities of muscle tone in adults include:
Weakness and problems with mobility and balance are common in these conditions but muscle tone may also be affected.
If hypotonia is suspected in a newborn baby or young child, they will be referred to a specialist. This will usually be a specialist paediatrician or neurologist.
The specialist will start by asking you a number of questions which are likely to include:
Following the initial assessment, a full physical examination will be carried out. Some of the conditions that can cause hypotonia involve problems with other organs. A number of investigations will be suggested, including blood tests.
Other tests that may be recommended include:
In some cases of hypotonia, no underlying cause can be found despite carrying out exhaustive tests. This is sometimes referred to as "benign congenital hypotonia". However, this is a rather controversial term and some experts recommend ongoing follow-up in such cases.
The recommended treatment plan for hypotonia (decreased muscle tone) will depend on the underlying cause.
Hypotonia that is caused by a baby being born prematurely will usually improve as the baby gets older. However, specialist treatment and support may be needed during this time and for other problems associated with prematurity.
Hypotonia in babies born to mothers with myasthenia gravis (a condition that causes weakness in certain muscles) usually improves quickly. Again, specialist treatment and support may be needed while the baby improves.
In cases where hypotonia is caused by an infection, the symptoms may disappear if the infection can be successfully treated.
If it is not possible to cure the underlying cause of hypotonia (as is unfortunately often the case) the two main treatments will be physiotherapy and occupational therapy.
In treating hypotonia, the main objectives of physiotherapy are to:
The physiotherapist will ask you to perform a series of exercises and tasks. They will also teach you a range of exercises that you can do on a daily basis.
Read more about physiotherapy.
Occupational therapy teaches you the skills that are needed to carry out day-to-day activities. For example, the occupational therapist will focus on improving the hand and finger skills that are needed for dressing and feeding.
As with physiotherapy, you will be asked to attend regular occupational therapy sessions. You will receive training so that you can perform exercises and tasks on a daily basis.
Read more about occupational therapy.
Speech and language therapy (SLT) may be recommended in cases where speech and swallowing problems are associated with hypotonia. SLT can also help to develop better control of the jaw and mouth muscles.
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.