Hypertonia and Cerebral Palsy

What Is Hypertonia?

Hypertonia is a condition in which there is an excessive amount of activity (muscle tone) in a muscle when a person does not intend to move it. Hypertonia is the opposite of hypotonia, which means too little muscle tone. However, it is important to note that some individuals may be affected by both issues.

The amount of tone in a muscle is controlled by signals from the brain that tell it when to contract. These signalling pathways sometimes function improperly in people who have neurodevelopmental disabilities like cerebral palsy (CP), who have had a brain injury or stroke, been exposed to neurotoxins, or have a disease like multiple sclerosis (MS), Parkinson’s, or brain cancer. Among other problems, hypertonia can cause stiffness, problems with balance, and spastic reflexes.

How Is Hypertonia Related to Cerebral Palsy?

People with cerebral palsy may have both hypertonia and hypotonia. In some cases, such as athetoid/dyskinetic cerebral palsy, muscle tone can frequently fluctuate between the two. The most common type of cerebral palsy is spastic CP. Spasticity is an outcome of hypertonia. People with spastic CP have velocity-dependent resistance to movement. In other words, the faster a joint is straightened, the tighter it feels. Symptoms of spastic CP may also include spasms, pain, and involuntary muscle contractions. In some cases, people also develop issues like early-onset arthritis, joint deformities, and scoliosis.

Treatments for Hypertonia and Spasticity

Spastic cerebral palsy can be treated with muscle-relaxing drugs such as botulinum toxin (botox) or baclofen. Botox is usually used to alleviate the symptoms of hypertonia in a specific area; its effects are localized. Baclofen has a more general effect on the body. It can be taken orally, transdermally, or through a pump that injects it directly into the cerebrospinal fluid. Symptoms can also be improved through physical therapy and occupational therapy.


National Institute of Neurological Disorders and Stroke: Hypertonia Information Page

Center for Cerebral Palsy at UCLA: Features of CP