Perseveration is the senseless repetition of words or deeds by a person with a disordered mind.
n. 1. excessive persistence at a task that prevents the individual from turning his or her attention to new situations. It is a symptom of organic disease of the brain and sometimes of obsessive–compulsive disorder. 2. the phenomenon in which an image continues to be perceived briefly in the absence of the object. This is a potentially serious neurological disorder.