Hypertonia

Hypertonia is a condition marked by an abnormal increase in the tightness of muscle tone and a reduced ability of a muscle to stretch (i.e. an increased stiffness). It is generally accompanied by (increased) spasticity of the particular muscles.

Damage to upper motor neurons causes hypertonia, as well as spasticity (overactive reflexes) and rigidity (constant muscle contractions). A form of hypertonia is known as Paratonia which is associated with dementia.