(Low Muscle Tone)
What is it?
Hypotonia, or low muscle tone is when the muscles of the body have a lower resistance to tension or being stretched. Tone is resistance to muscle stretch.
Typical muscle tone resists gravity easily. You don’t have to constantly think about holding yourself upright while walking or sitting, it’s just something that happens.
There are varying levels, mild to severe, which are generally indicators of the cause.
Mild hypotonia could look like someone who is “double jointed” or very flexible. Someone with very fluid movements or someone who is clumsy. But in a child or infant, they could be delayed developing later motor skills such as crawling, sitting, walking. They may also have a more rounded posture since they have to work harder to maintain it.
Moderate to severe hypotonia in infants is more pronounced. These children are often “floppy” and very delayed in early motor skills, including holding their head up, bringing hands to the bottle or toys, and may lose milk from the corners of the mouth (low oral tone). These babies often have weak or quiet cries. Moderate to severe hypotonia is usually a symptom of something else (prematurity, Down Syndrome, Fragile X, etc).
What is it not?
Hypotonia is not:
- muscle weakness
- hypERtonia (HIGH muscle tone)
- not indicative of a cognitive disorder or intellectual impairment
- not a sign or symptom of autism
What causes it?
Hypotonia can be an indicator of other neurological problems (malignant) or it could be a random genetic gift (benign). Here are a few diagnoses where hypotonia is common:
Benign Congenital Hypotonia: This is a controversial diagnosis basically saying doctors aren’t sure why it is happening, all other areas look good, and the child will likely outgrow any motor delay.
Genetics: Praeder- Willi syndrome, Down Syndrome, Spinal Muscle Atrophies, Muscular dystrophies, Metabolic disorders.
Central Nervous System: Cerebral Palsy, Meningitis, Spinal Cord Injuries
Non Neurological: Being born prematurely, Hypothyroidism, Connective Tissue Disorders.
If you are concerned about your child or believe he is falling behind with motor skills, contact your primary care physician (PCP).
If a hypotonia diagnosis has been suggested or mentioned, it is worth your time to ask your PCP about a Neurology consultation, a Genetics consultation, and a gross motor evaluation done by either an Occupational therapist or a Physical therapist.
While you are in this process, continue to treat your child as you would any other. Continue to love, comfort, challenge and teach them.