Perseveration

Perseveration, in the fields of psychology, psychiatry, and speech–language pathology, is the repetition of a particular response (such as a word, phrase, or gesture) 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 (a highly repetitive idiosyncratic behaviour). In a broader sense, it is used for a wide range of functionless behaviours that arise from a failure of the brain to either inhibit prepotent 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 (changing of goals, tasks or activities) 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. Etymologically, the term derives from "persevere", meaning "to continue determinedly", from Latin "perseverare", meaning "to persist": persistent behaviour directed toward an identifiable goal is called "perseverance", but when not directed toward such a goal is called "perseveration". In general English, "perseveration" refers to insistent or redundant repetition, not necessarily in a clinical context.