Authors:

Hodges, J.R., Patterson, K., Graham, N. & Dawson, K.

Reference:

Year of publication:

1996

CBU number:

3417

Abstract:

We studied the relationship between naming and the integrity of physical and associative knowledge in a group of patients with dementia of the Alzheimer type (DAT) and matched normal controls. All subjects named 48 line drawings and later generated verbal definitions in response to the names of a subset of the 48 items, which included a minimum of 6 definitions for correctly named objects and 6 definitions for items that the subject failed to name. A comprehensive scoring system was designed by the definitions, including physical and associative features of a general and specific type, a superordinate label, the core concept, and various categories of errors. The definitions generated by the DAT patients, even those in the minimal group, contained significantly less correct information than those of normal subjects, and definitions corresponding to un-named items were more impoverished than those for named items. Particularly striking was the loss of core concept of un-named items. There was also a disproportionate reduction in physical information on un-named compared to named items. We conclude that quantitative assessment of verbal definitions is a sensitive index of semantic memory breakdown. Our findings offer some support for the hypothesis that successful name depends upon integrity of the subset semantic knowledge comprising physical features.