What is Hypotonia

Hypotonia is decreased muscle tone. Muscle tone is the amount of tension or resistance to movement in a muscle while at rest. Muscle tone is different from muscle strength, which is how much force a muscle can apply.

Often, a person with hypotonia will also have weak muscles. Hypotonia is often a symptom of a serious underlying condition or a problem at birth.

Hypotonia can be a short-term condition, such as when a baby is born prematurely, or a lifelong (chronic) condition. Hypotonic infants are referred to as “floppy” infants because of their abnormally limp bodies and lack of control over their movements.

What are the causes?

In some cases, the cause of this condition is not known. Possible causes include:

• Injury or damage (trauma). Hypotonia is often caused by trauma that occurred before, during, or right after birth (perinatal trauma).
• Genetic disorders.
• Nerve disorders.
• Muscle disorders.
• Central nervous system (CNS) disorders.
• Problems in the connections between nerves and muscles (neuromuscular junctions).
• Problems in the tissues that connect bones to one another (ligaments).
• Serious infections.
• Premature birth.

What are the signs or symptoms?

Symptoms of this condition vary based on the cause and the patient’s age. The main symptoms include:

• Low muscle tone in the entire body or in specific areas of the body.
• Joints that are unusually flexible. This is often seen in the hips, elbows, and knees.
• Poor reflexes.
• Muscle weakness.

Symptoms in Infants

• Limp or “floppy” movements.
• Little to no control of the neck muscles.
• Inability to place weight on the limbs.
• Limbs than hang straight down instead of bending at the joints.
• Delayed development, especially with actions that involve the muscles (motor skills).
• Poor sucking ability and poor weight gain.
• Decreased alertness.

Symptoms in Older Children and Adults

• Weight loss.
• Difficulty getting up and reaching for objects.
• Double vision.
• Decreased energy.
• Poor posture and balance.

Depending on the cause, symptoms may improve, stay the same, or get worse over time.

How is this diagnosed?

This condition is often diagnosed during infancy, but sometimes it can develop in older children and adults. Diagnosis is based on a physical exam and medical history. You may have tests, including:

• MRI.
• CT scan.
• Electromyogram with nerve conduction studies (EMG with NCS). This evaluates the function of the nerves, neuromuscular junctions, and muscles.
• Electroencephalogram (EEG). This records brain activity.
• Removal of a small number of muscle or nerve cells that are examined under a microscope (biopsy).
• Genetic testing.

You may be given the name of a health care provider who specializes in CNS disorders (neurologist).

How is this treated?

Treatment for hypotonia depends on the cause. Treatment options include:

• Treating the underlying condition that causes your hypotonia, if this applies.
• Physical therapy to improve motor skills and functional strength.
• Occupational therapy to improve skills needed for everyday activities, such as fine motor skills (dexterity).
• Speech-language therapy to overcome difficulty swallowing and talking.

Follow these instructions at home:

• Take over-the-counter and prescription medicines only as told by your health care provider.
• Pay attention to any changes in your symptoms.
• Use equipment, such as braces or wheelchairs, as told by your health care provider.
• If you feel weak or unstable, sit or lie down right away.
• Ask your health care provider what activities are safe for you. You may be told to avoid certain physical activities.
• Ask for help when you need it, such as when lifting heavy objects or reaching for things.
• Keep all follow-up visits as told by your health care provider. This is important.

Contact a health care provider if:

• You have side effects from any medicines you are taking.
• Your symptoms suddenly change or get worse.
• You have unusual stiffness.
• You have a sudden change in mood or behavior.
• You feel hopeless or depressed.

Get help right away if:

• You have difficulty breathing.
• You have difficulty seeing or your vision changes.
• You have numbness in part of your body.