Hypertonia Increased tension or stiffness in the muscles is often associated with Cerebral Palsy. Untreated hypertonia can lead to loss of function and deformity. Spastic hypertonia can involve uncontrollable muscle spasms. This can include “flapping” and other repetitive motions like rocking. Dystonia hypertonia describes rigidity, which is the involuntary stiffening of muscles. Treatments involve occupational and physical therapy including range of motion and stretching. Drugs such as Diazepam may be prescribed to reduce spasticity.