Lexical and Semantic Spreading Activation in Mild to Moderate Alzheimer's Disease

Abstract

The current study investigates potential significant differences in spreading activation within semantic networks in a sample of patients diagnosed with mild Alzheimer’s Disease (AD), moderate AD, and normal, healthy controls. Prior research on spreading activation in semantic networks has used previously developed corpora that are either outdated and/or derived from various media materials (e.g., books, film, television). We developed a new corpus from participant responses to the Controlled Oral Word Association Test (COWAT) and the Animal Naming (AN) test to subsequently calculate the word frequencies of the responses from patients with mild AD, moderate AD, and controls to the same tests. Results indicated reduced spreading activation in the moderate AD group with relative lexical network preservation across all three groups. These results support known AD pathology with a degradation of semantic networks as the disease progresses through the entorhinal cortex. Implications and future directions are discussed.