What is hypotonia?
Hypotonia is a term that describes decreased muscle tone. Typically, muscles have a very small amount of contraction that gives them a springy feel even when relaxed. This also provides some resistance to passive movement. It is not the same as muscle weakness, although the two conditions can happen at the same time.
Muscle tone is controlled by signals that travel from the brain to the nerves and tell the muscles to contract. Hypotonia can result from damage to the brain, spinal cord, nerves, or muscles. Hypotonia does not affect intellect. The opposite of hypotonia is hypertonia.
The damage can be the result of the following; however, it may not be possible to find the cause:
- Environmental factors
- Genetic, muscle, or central nervous system disorders
Hypotonia can be seen in:
- Down syndrome
- Muscular dystrophy
- Cerebral palsy
- Prader-Willi syndrome
- Myotonic dystrophy
- Tay-Sachs disease
Infants with hypotonia may 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 include:
- Problems with mobility and posture
- Breathing and speech difficulties
- Ligament and joint laxity
- Poor reflexes
Treatment begins with a thorough diagnostic evaluation. This is usually performed by a neurologist and includes an assessment of:
- Motor and sensory skills
- Balance and coordination
- Mental status
- Functioning of the nerves
Once a diagnosis has been made, the underlying condition is treated first. This is followed by treatment to improve symptoms and provide support, and may include physical, occupational, and speech-language therapies. Therapy for infants and young children may also include sensory stimulation programs.
Hypotonia can be a life-long condition. In some cases, muscle tone improves over time.
How can I or my loved one help improve care for people with hypotonia?
Consider participating in a clinical trial so clinicians and scientists can learn more about hypotonia and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.
All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.
Where can I find more information about hypotonia?
The following organizations and resources may provide more information: