Semantic Degradation and Lexical Access in Age-Related Naming Failures

This study investigated the impaired lexical access and semantic degradation hypotheses as two potential explanations of naming failures in normal aging. Naming responses on the Boston Naming Test (BNT) and Action Naming Test (ANT) were analyzed across three test sessions for 39 adults from three age groups (50s, 60s, and 70s). Failures to name before and after cues were classified as either impaired access if failures occurred at an earlier test session followed by successful naming at a later test session or semantic degradation if naming was successful at an earlier test session followed by failures at a later test session. The results indicated that on both the BNT and ANT all age groups produced more naming failures attributed to impaired access than to semantic degradation. However, for object naming, the failures showed significantly more semantic degradation for people in their 70s compared to the younger age groups. By contrast, for action naming, semantic degradation was negligible, possibly masked by a ceiling effect, and the only age-difference result that approached significance indicated that adults in their 70s produced more naming failures attributed to impaired access than adults in their 50s.