Hypotonia is a medical term used to describe decreased muscle tone (the amount of resistance to movement in a muscle). The condition is also known as Floppy Infant Syndrome or Infantile Hypotonia. It is not the same as muscle weakness, although the two conditions can co-exist.

Hypotonia can be a life-long condition. In some cases, however, muscle tone improves over time.

Hypotonia may be caused by:

  • Trauma
  • Environmental factors
  • Genetic disorders
  • Muscle disorders
  • Central nervous system disorders

Some disorders that can cause hypotonia include:

Sometimes it may not be possible to find what causes hypotonia.

Infants with hypotonia have a floppy quality or “rag doll” appearance because their arms and legs hang by their sides and they have little or no head control. Other symptoms of hypotonia include:

  • Problems with mobility and posture
  • Breathing difficulties
  • Speech difficulties
  • Lethargy
  • Ligament and joint laxity
  • Poor reflexes

Hypotonia does not affect intellect. However, depending on the underlying condition, some children with hypotonia may take longer to develop social, language, and reasoning skills.

When hypotonia develops in the adult years, it may be due to diseases associated with cerebellar degeneration (such as multiple sclerosis, Friedreich’s ataxia, or multiple system atrophy) in which neurons in the cerebellum — the area of the brain that controls muscle coordination and balance — deteriorate and die.

Recognizing hypotonia, even in early infancy, is usually relatively straightforward, but diagnosing the underlying cause can be difficult and often unsuccessful. Hypotonia is a condition that can be helped with early intervention.

Treatment begins with a thorough diagnostic evaluation. Once a diagnosis has been made, the underlying condition is treated first, followed by symptomatic and supportive therapy for the hypotonia. Physical therapy can improve fine motor control and overall body strength. Occupational and speech-language therapy can help breathing, speech, and swallowing difficulties. Therapy for infants and young children may also include sensory stimulation programs.