Varieties of perseveration: a comparison of two taxonomies

Two taxonomies of perseveration have been independently developed by Goldberg and Tucker (1979) and Sandson and Albert (1984). They are in remarkable agreement with respect to phenomenology of perseveration but differ in terms of postulated mechanisms. Sandson and Albert propose a separate mechanism for every type, whereas Goldberg and Tucker propose a unitary mechanism which can operate at different levels of neurocognitive hierarchy thus producing different types of perseveration. The issue of neuroanatomical specificity of perseveration is also addressed. It is proposed that clinical features of prefrontal syndromes need not imply the presence of selective structural or biochemical damage to prefrontal cortex, and that a structurally diffuse CNS disease often masquerades as a selective frontal-lobe disease. The difference between structural and functional definitions of focal brain disease is emphasized.