If patient's with lesions to the cerebellum were asked to throw darts at a dart board while wearing a pair of prisms that shifted their vision to the right:
The cerebellum is the part of the brain that is very much essential for learning and controlling movements. A person who is in such situation needs assistance because part of the cerebellum's function also has something to do with a person's perceptual abilities. Overall when a person has an injury on the cerebellum it would be hard for him to have both motor and sensory control of his body.