The longitudinal neurodegenerative impact of Alzheimer's disease on picture naming
Although semantic memory impairment is well-documented in patients with Alzheimer's disease (AD), it remains unclear if this neurodegenerative disease differentially affects semantic domains. Most studies have found that AD patients show differential impairments in their knowledge for living things (e.g. animals), a minority have also reported nonliving thing deficits (e.g. tools), while some have also found no evidence of category-specific effects at all in AD patients. In a longitudinal study, we observed the naming performance of a group of AD patients twice across an interval of one year. We investigated whether categorical effects or intrinsic variables (such as age of acquisition, familiarity, name agreement or visual complexity of the items) have a greater impact on naming performance. We conclude that intrinsic variables are better predictors of naming performance in both, AD and healthy participants, rather than the categorical status of the items.