Although it’s sometimes called Floppy Baby Syndrome, Hypotonia is the medical term used to describe abnormally low muscle tone. Normally, even relaxed muscles have a very small amount of contraction that gives them a springy feel and provides some resistance to passive movement. It is not the same as muscle weakness, although hypotonia and weakness can often go hand in hand. Muscle tone is regulated by signals that travel from the brain to the nerves and tell the muscles to contract. Hypotonia does not affect intelligence. Pediatric therapy helps children overcome hypotonia; the primary treatment for most children with congenital hypotonia is occupational and physiotherapy.
Hypotonia can be seen in children with Down syndrome, cerebral palsy, autism spectrum disorder, muscular dystrophy, Marfan’s syndrome, and Sensory Processing Disorder (not an official DSM diagnosis), among other diagnoses. Sometimes, the cause of hypotonia remains a mystery, with no clear diagnosis. Hypotonia can happen from damage to the brain, spinal cord, nerves, or muscles. The damage can be from trauma, environmental factors, or genetic, muscle, or central nervous system disorders.
Hypotonia in infants is usually noticeable by 6 months of age, by which time the low muscle tone in babies typically becomes apparent. Babies with hypotonia have a floppy quality because their arms and legs hang, and they tend to have little or no head control. Children with hypotonia may have difficulty transitioning in and out of positions and be slow to attain motor milestones, resulting in global developmental delay. Hypotonia in toddlers may cause movements with clumsy or inefficient patterns, difficulty with hand-eye coordination, and a preference to sit and watch rather than move and groove with other kids. Other symptoms of hypotonia include problems with mobility and posture (such as difficulty sitting upright without significant leaning or support), breathing and speech difficulties, ligament and joint laxity, poor reflexes, and getting easily frustrated with physical challenges.
Cait Parr is a pediatric physiotherapist at NAPA Center. Her favorite animal is snails, because they remind her to slow down and enjoy the beautiful details about life. She loves desserts almost as much as she loves long walks with her husband on the beach at sunset.