Diagnosing hypotonia 

If hypotonia (decreased muscle tone) is suspected in a newborn baby or young child, they'll be referred to a specialist.

This will usually be a paediatrician (a specialist in treating children) with expertise in disorders of the nerves and nervous system, or a neurologist (a specialist in disorders of the nerves and nervous system).

The specialist will start by asking a number of questions, which are likely to include:

  • details about your pregnancy
  • details about your delivery
  • whether there have been any problems since the birth, such as seizures (fits) or feeding difficulties
  • whether any other family members have had similar problems

Following the initial assessment, a full physical examination will be carried out and a blood test may be offered.

Other tests that may be recommended include:

  • computerised tomography (CT) scans or magnetic resonance imaging (MRI) scans – these detailed scans can be used to detect any nervous system damage or abnormalities
  • electroencephalogram (EEG) – a painless test that records brain activity using small electrodes placed on the scalp
  • electromyography (EMG) – where the electrical activity of a muscle is recorded using small needle electrodes inserted into the muscle fibres
  • nerve conduction studies – where nerve activity is measured using small metal disc electrodes placed on the skin over the nerve
  • muscle biopsy – where a small sample of muscle tissue is taken and examined under a microscope
  • genetic testing – you or your child may be referred for genetic testing, which is a way of finding out whether you're carrying a particular genetic mutation (altered gene) that causes a medical condition

In some cases, no underlying cause can be found despite numerous tests. This is sometimes referred to as benign congenital hypotonia. In this situation, treatment and support can be offered to manage functional difficulties after other causes of hypotonia have been excluded.

Page last reviewed: 30/06/2015

Next review due: 01/06/2018