Hypotonia is a condition in which a person has decreased muscle tone. It is more common to see hypotonia in children than it is in adults, although children with the condition can have it their entire lives. A condition that equally affects males and females, hypotonia is becoming more common than it used to be. This is because the survival rate of those who are more likely to be born with a disorder that causes hypotonia is higher than it was in the past. Extremely premature infants, for example, are at high risk of having neurological problems which is a cause of hypotonia.
It is common to see hypotonia in children who have disorders in which it is a symptom, such as central nervous system (CNS) disorders and neuromuscular disorders. The most common disorders in which hypotonia in children occur is cerebral palsy and Down syndrome, although other disorders that can cause the condition include muscular dystrophy, Prader-Willi syndrome, and Tay-Sachs disease. Of the neurological problems seen in newborns, hypotonia is the most common condition found that involves muscular abnormalities. Sometimes, though, an underlying cause of hypotonia remains unknown.
In infants, hypotonia is often known as floppy infant syndrome. This name refers to the “rag doll” feeling that characterizes the lack of muscle tone where the infant will rest with loosely extended elbows and knees instead of flexed elbows and knees like that of one with normal muscle tone. In addition to having arms and legs that hang limply, an infant with hypotonia also has poor or no control of the head. Instead of being able to keep a certain level of head control, the infant’s head will fall back, forward, or to the side. To illustrate a “rag doll” effect, an infant with hypotonia will demonstrate little resistance when he or she is being picked up, much like that of a rag doll.
Other signs of hypotonia in children, and adults, include flexible ligaments and joints, poor reflexes, and problems with movement and posture. In addition, persistent hypotonia in children can cause difficulties and delays in learning gross motor skills, which include crawling, sitting, and walking. Treatment of hypotonia involves first diagnosing the underlying medical condition and treating it, if possible. Following this, hypotonia treatment might include physical therapy, sensory stimulation therapy, and speech-language therapy. Over time, an affected child’s muscle tone might improve, but it is possible that he or she will live with hypotonia his or her entire life.