- Praxis refers to the ability to plan and carry out complex, purposeful movements and is impaired in apraxia. Apraxia is characterized by the loss of the ability to perform movements despite having the physical ability and willingness. There are several types of apraxia that affect different motor functions like speech, eye or limb movements. Apraxia is caused by conditions that damage brain areas controlling movement like stroke, brain tumors, Alzheimer's disease or head injuries. Clinical manifestations of apraxia include difficulties with speech like distorted words, incorrect word order or stress.