Verbal perseveration of dementia patients.

Patterns of perseveration and frequency of carrier phrases were studied in the verbal descriptive discourse of dementia patients controlled for etiology and severity. Dementia patients were found to perseverate significantly more frequently than normals and severity of dementia was more strongly associated than etiology with increased perseveration. Frequency of carrier phrases did not distinguish the descriptive discourse of dementia patients from normals. Discontinuous perseveration was more common than continuous perseveration, and perseveration of ideas after an intervening response was the perseverate most typical of the dementia patient. Findings of the study are related to prominent theories of the cause of perseveration.