What is hemibalismus characterized by?

Hemibalismus is characterized by sudden, violent movements of the limbs, particularly on one side of the body. This condition is typically associated with damage to the subthalamic nucleus, which is part of the basal ganglia system responsible for coordinating movement. The hallmark of hemibalismus is these flinging movements, which are uncontrollable and can be quite dramatic.

The other options describe different movement disorders or symptoms. Involuntary eye movements pertain to conditions such as nystagmus or strabismus. Repetitive muscle twitching is more indicative of conditions like myoclonus, where there are brief, involuntary jerks of muscle or muscle groups. Involuntary facial grimacing is often associated with tic disorders or neurological conditions affecting facial musculature. Each of these options reflects a different symptomatology and is not representative of the distinctive movements seen in hemibalismus.