P3-107: Semantic error patterns on naming test in normal aging, amnestic mild cognitive impairment and mild Alzheimer's disease: Is there semantic disruption?

Abstract

Naming difficulty is common in Alzheimer′s disease (AD) but its nature is not well established. We investigated the presence of semantic breakdown and the pattern of general and semantic errors in 16 patients with mild AD, 16 with amnestic mild cognitive impairment (aMCI) and 16 normal controls by examining their spontaneous answers on the Boston Naming Test (BNT) and verifying if they needed or were benefited by semantic and phonemic cues. The errors of spontaneous answers were put in four mutually exclusive categories (semantic, visual paragnosia, phonological and omission errors) and the semantic errors were further subclassified in coordinate, superordinate, and circumlocutory. We submitted the percentage of correct answers after semantic and phonemic cues for each participant to a separate one-way ANOVA. The same was done with the errors' type after spontaneous answers, as well as with semantic errors' subtypes. Data analysis by means of Systat software and statistical significance considered was p < 0.05. AD performed worse on BNT than aMCI and controls (p<0.001 on both groups), while aMCI was similar to controls (p=0.46). After semantic cue, AD scored on 21.76%, aMCI on 50.04% and controls on 55.4% of times (AD × aMCI: p=0.02; AD × controls: p=0.002; aMCI × controls: p=0.67). After phonemic cues, AD scored on 39.47%, aMCI on 38.6% and controls on 44.86% (p=0.40). Spontaneous and semantic errors patterns were similar between 3 groups: omission (p=0.60), visual paragnosia (p=0.07) and semantic (p=0.11); circumlocutory (p=0.54), coordinate (p=0.77), and superodinate (p=0.96). aMCI patients performed normally on BNT and needed less semantic and phonemic cues than mild AD patients. After semantic cues, aMCI and control subjects named more properly than mild AD, but after phonemic cues there was no difference between the three groups suggesting that AD patients' low performance cannot be completely explained by semantic breakdown. Patterns of spontaneous naming errors and subtypes of semantic errors were similar in the three groups.