Perseveration according to psychology, psychiatry, and speech-language pathology, is the repetition of a particular response regardless of the absence or cessation of a stimulus. It is usually caused by a brain injury or other organic disorder. Symptoms include "lacking ability to transition or switch ideas appropriately with the social context, as evidenced by the repetition of words or gestures after they have ceased to be socially relevant or appropriate", or the "act or task of doing so", and are not better described as stereotypy. In a broader sense, it is used for a wide range of functionless behaviours that arise from a failure of the brain to either inhibitprepotent responses or to allow its usual progress to a different behavior, and includes impairment in set shifting and task switching in social and other contexts. The primary definition of perseveration in biology and clinical psychiatry involves some form of response repetition or the inability to undertake set shifting as required, and is usually evidenced by behaviours such as words and gestures continuing to be repeated despite absence or cessation of a stimulus. More broadly in clinical psychology, it describes mental or physical behaviours which are not excessive in terms of quantity but are apparently both functionless and involve a narrow range of behaviours. In etymology, the term derives from "persevere", meaning "to continue determinedly", from Latin "perseverare", meaning "to persist": to persist with clear intentions is said "to persevere", but when those intentions are lost and only the persistence remains, one is said "to perseverate". In general English, "perseveration" refers to insistent or redundant repetition, not necessarily in a clinical context.
Associated conditions and manifestations
Perseveration of thought indicates an inability to switch ideas or responses. An example of perseveration is, during a conversation, if an issue has been fully explored and discussed to a point of resolution, it is not uncommon for something to trigger the reinvestigation of the matter. This can happen at any time during a conversation. Physical brain injury, trauma or damage
Perseveration is sometimes a feature of frontal lobe lesions, and of other conditions involving dysfunction or dysregulation within the frontal lobe. This is especially true when the lateral orbitofrontal cortex or inferior prefrontal convexity are affected.
Perseveration is also sometimes seen as a symptom of aphasia.
Apart from their direct symptoms, people with obsessive–compulsive disorder can have specific problems with set shifting and inhibition of prepotent responses.
Confounds
Perseveration may be confused with habitual behaviours in a number of other conditions and disorders, such as obsessive–compulsive disorder, including post-traumatic stress disorder, body dysmorphic disorder, trichotillomania, and habit problems. However, in animal experiments it can be shown when repetitive behaviour is a cognitive perseveration rather than a motor disorder. For example, under low doses of amphetamine an animal will perseverate in maintaining an arbitrary object preference even when different motor responses are required to maintain that preference.
Unproven:
Several researchers have tried to connect perseveration with a lack of memory inhibition ; however, this connection could not be found, or was small.
