Perseveration or the Tower of Babel.

The purpose of this article is twofold: (1) to present a study of perseveration in a continuous series of 50 left brain-damaged aphasic subjects and (2) to describe the treatment of 2 patients with high rates of perseveration. In the group of 50 subjects, 20 showed two or more perseverations in one or more language tasks. No difference in number of perseverations was found between fluent and nonfluent subjects, but perseverations in global aphasic subjects with stereotyped speech were less varied than they were in fluent aphasic subjects and were not unlike other types of recurrent utterances. Of the two patients who received treatment, subject 1 had severe semantic disruption and perseverated in all production and comprehension tasks, except in repetition, reading aloud, and writing to dictation, all of which could be performed by the undamaged sublexical routines. Treated subject 2 had writing disorders that were ascribed to damage to the output buffer. She perseverated in all writing tasks. Rehabilitation of the semantic system in subject 1 and of the output buffer in subject 2 greatly reduced the number of perseverations in both subjects. It is argued that recovery of the underlying functional damage reduces the perseverative behavior.