Comparison of the Semantic Networks in Patients With Dementia and Amnesia

The semantic networks of 13 patients with Alzheimer's disease (AD), 13 patients with Huntington's disease (HD), 8 amnesic (AM) patients, and 26 controls were generated by multidimensional scaling and Pathfinder analyses of their responses on a triadic comparison task. The semantic networks of HD and AM patients were essentially normal, whereas the networks of AD patients were deviant in a number of ways. The AD patients' networks were dominated by a different dimension, had fewer common links, and consisted of associations of atypical strength. These results suggest that structural alteration of semantic networks is characteristic of Alzheimer's disease and is not evident in all forms of dementia and amnesic conditions.