Research Description:

Memory for General and Specific Words in Alzheimer Disease

The focus of this University Scholars study is to investigate people’s memory for specific versus general words. This study is part of a larger study that will examine the effects of using general versus specific words on the sentence production of individuals with Alzheimer’s disease (AD). Research has shown that individuals with AD use many general words in spontaneous speech and have serious difficulties with sentence production when they must include very specific words in their sentences (Altmann, 2004  Altmann et al., 2001). The underlying hypothesis of this work is that using specific words puts a larger burden on memory than general words, because their representations include more semantic features than general words. These effects should be exaggerated in individuals with Alzheimer disease, because they have impairments in both memory and the semantic system.

As a part of this larger study, I will assess 20 healthy older adults (HOA) and 20 adults diagnosed with mild to moderate AD by testing their memory of general and specific words in two tasks: one requiring just repetition of the words, and one requiring storage and manipulation of the words. Both tasks are patterned after the Digit Span task (Wechsler, 1987). In the storage-only version, participants will repeat increasingly long lists of either general or specific words. Testing is discontinued if a person fails on both trials at a given list length. In the storage-and-manipulation version, participants will repeat the words in the reverse order that they were given. Therefore, this study will have two within-group variables (type of task: forward or backward memory, and type of word: general or specific) and one between-group variable (group: HOA and AD).

These findings will help us determine whether specific words put more of a memory burden on speakers than general words, and whether this affect is exaggerated by this semantic impairment in Alzheimer’s disease. They will also help us understand why “empty speech” is so common in other people with semantic impairments, such as semantic dementia and Wernicke’s aphasia.