Conceptual fluency at test shifts recognition response bias in Alzheimer's disease: Implications for increased false recognition

Abstract

The presence or absence of conceptual information in pictorial stimuli may explain the mixed findings of previous studies of false recognition in patients with mild Alzheimer's disease (AD). To test this hypothesis, 48 patients with AD were compared to 48 healthy older adults on a recognition task first described by Koutstaal et al. [Koutstaal, W., Reddy, C., Jackson, E. M., Prince, S., Cendan, D. L., & Schacter D. L. (2003). False recognition of abstract versus common objects in older and younger adults: Testing the semantic categorization account. Journal of Experimental Psychology: Learning, Memory, and Cognition, 29, 499-510]. Participants studied and were tested on their memory for categorized ambiguous pictures of common objects. The presence of conceptual information at study and/or test was manipulated by providing or withholding disambiguating semantic labels. Analyses focused on testing two competing theories. The semantic encoding hypothesis, which posits that the inter-item perceptual details are not encoded by AD patients when conceptual information is present in the stimuli, was not supported by the findings. In contrast, the conceptual fluency hypothesis was supported. Enhanced conceptual fluency at test dramatically shifted AD patients to a more liberal response bias, raising their false recognition. These results suggest that patients with AD rely on the fluency of test items in making recognition memory decisions. We speculate that AD patients' over reliance upon fluency may be attributable to (1) dysfunction of the hippocampus, disrupting recollection, and/or (2) dysfunction of prefrontal cortex, disrupting post-retrieval processes.

Enhancing the Salience of Fluency Improves Recognition Memory Performance in Mild Alzheimer's Disease

“…These findings contradict the frequent observation that AD patients show an abnormally liberal response bias independently of poorer discrimination abilities [10,52]. Moreover, enhancing patients' reliance on fluency was often found to shift them to a more liberal response bias [5,32]. Although it remains unclear what determines the response bias adopted by AD patients, it seems that, in certain conditions, they are not biased towards "yes" answers or even show conservative criteria [44,53,54].…”

“…Second, more direct evidence indicates that it is possible to induce false recognitions in mild AD patients by artificially enhancing perceptual or conceptual processing fluency at the time of test, for instance through masked visual priming [30] or by using a predictive conceptual context [5,31,32]. For example, AD patients are more likely to endorse as old the word "boat" (studied or not) if it is preceded by the predictive sentence stem "The stormy seas tossed the…" than if preceded by the non-predictive stem "She saved up her money and bought a…".…”

Poder preditivo do MoCa na avaliação neuropsicológica de pacientes com diagnóstico de demência

“…[35][36][37] Gainotti et al 35 encontraram diferenças significativas entre DA e pseudodemência depressiva em relação ao desempenho cognitivo em tarefas que avaliam a memória imediata e erros de intrusão na memória tardia. Em outras demências, Giovannetti et al 36 compararam a demência vascular com a DA e verificaram que, no caso das demências vasculares, há o comprometimento na formação de conceitos e, no caso da DA, esses déficits são secundários ao comprometimento da resposta verbal.…”

“…Em outras demências, Giovannetti et al 36 compararam a demência vascular com a DA e verificaram que, no caso das demências vasculares, há o comprometimento na formação de conceitos e, no caso da DA, esses déficits são secundários ao comprometimento da resposta verbal. Com relação a este comprometimento, Gold et al 37 sugerem que pacientes com DA apresentam disfunção do hipocampo e também do córtex pré-frontal, por apresentarem declínio da fluência.…”

“…[35][36][37][38] Considerando o teste MoCA, os dados desta pesquisa evidenciam que a maioria de seus itens consegue diferenciar os três grupos diagnósticos. Vale ressaltar que o MoCA foi desenvolvido como ferramenta de avaliação diagnóstica para o CCL e casos leves de demência.…”