Hypotonia (Floppy Infant Syndrome)

Hypotonia is a medical term used to describe decreased muscle tone (the amount of resistance to movement in a muscle). It is not the same as muscle weakness, although the two conditions can co-exist. Hypotonia may be caused by trauma, environmental factors, or by genetic, muscle, or central nervous system disorders, such as Down syndrome, muscular dystrophy, cerebral palsy, Prader-Willi syndrome, myotonic dystrophy, and Tay-Sachs disease. 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 and speech difficulties, lethargy, ligament and joint laxity, and 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.

Is there any treatment?

Treatment begins with a thorough diagnostic evaluation, including an assessment of motor and sensory skills, balance and coordination, mental status, reflexes, and functioning of the nerves. Diagnostic tests such as a CT scan of the brain, an EMG to evaluate nerve and muscle function, or an EEG to measure electrical activity in the brain may also be necessary. 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.

What is the prognosis?

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

What research is being done?

The NINDS supports research on conditions that can result from neurological disorders, such as hypotonia. Much of this research is aimed at learning more about these conditions and finding ways to prevent and treat them.

NIH Patient Recruitment for Hypotonia Clinical Trials

• At NIH Clinical Center
• Throughout the U.S. and Worldwide

Organizations

Muscular Dystrophy Association
3300 East Sunrise Drive
Tucson, AZ 85718-3208
mda@mdausa.org
http://www.mda.org
Tel: 520-529-2000 800-344-4863
Fax: 520-529-5300

March of Dimes Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
askus@marchofdimes.com
http://www.marchofdimes.com
Tel: 914-428-7100 888-MODIMES (663-4637)
Fax: 914-428-8203

National Organization for Rare Disorders (NORD)
P.O. Box 1968
(55 Kenosia Avenue)
Danbury, CT 06813-1968
orphan@rarediseases.org
http://www.rarediseases.org
Tel: 203-744-0100 Voice Mail 800-999-NORD (6673)
Fax: 203-798-2291

Prepared by: Office of Communications and Public Liaison National Institute of Neurological Disorders and Stroke National Institutes of Health Bethesda, MD 20892

NINDS health-related material is provided for information purposes only and does not necessarily represent endorsement by or an official position of the National Institute of Neurological Disorders and Stroke or any other Federal agency. Advice on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined that patient or is familiar with that patient's medical history.

All NINDS-prepared information is in the public domain and may be freely copied. Credit to the NINDS or the NIH is appreciated.