Final answer:
The movement disorder with the largest amplitude of motion is balism, characterized by violent, flinging movements of the limbs due to damage to the subthalamic nucleus.
Step-by-step explanation:
The movement disorder with the largest amplitude of motion is balism or ballismus. This disorder is characterized by violent, flinging movements of the limbs. These involuntary movements can be extremely large in amplitude and involve forceful contractions of the proximal limb muscles.
Balism is often caused by damage to the subthalamic nucleus of the basal ganglia, often as a result of a stroke or other forms of brain injury.
In comparison, myoclonus consists of brief, shock-like twitches. Tics are sudden, repetitive movements or sounds that are not as broadly flowing as those seen in balism. Athetosis involves slow, writhing movements, and chorea is characterized by irregular, dancelike movements that are not as violent or large in amplitude as balism. None of these have as large of a motion amplitude as balism, which is the most extreme in that respect.