The term perseveration is widely used for disturbance to end a task or switch to another task. The main feature of perseveration is the repetition, which has been linked to impaired inhibition of a preceding action.
Hugo Liepmann understood perseveration in a categorized meaning, not restricted to speech, motor, or emotional disturbance. The tonic perseveration is the persistence in an abnormal posture or task. He considered even grasping as tonic perseveration ‘the once started muscle contraction cannot be abandoned’. In contrast to this sustained innervation, the clonic perseveration is ‘alternating between contraction and atony’. The same task pattern recurs several times after their first presentation. Where as the intentional perseveration according to Liepmann is a recurrence of the same task, when the patient intends to do another task, seemingly being caught in a certain task pattern. ‘The repetition (of the task) does not occur autonomously. When ever (the patient) wants to initiate a new task, the old innervation complex is activated instead of a new one. (…)The previous excited neuronal complex persists in a state of a higher accessibility.’ (Liepmann, 1905).
There is a great diversity to the term perseveration in the literature nowadays. Many attempts have been made to categorize perseveration differently e.g. by Luria in 1965. Besides the original categorization from Liepmann published in German in 1905, no other taxonomy of the term was able to gain general acceptance. We refer to the original concept and display video examples of motor perseveration.