Navigation Ability in Advancing Alzheimer''s Disease Patients

• Main Authors: Ming-Chyi Pai, 白明奇
• Other Authors: Sigmund S. Hsiao
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/67840446141775165029

博士 === 國立中正大學 === 心理學研究所 === 90 === Alzheimer’s disease (AD) has become an important and prevalent degenerative disease in the elderly. In order to treat the patients earlier and manage them properly, it is important to detect their cognitive impairment as early as possible. Navigation and declarative memory share same neurosubstrate of hippocampal function. Since declarative amnesia is a major manifestation of preclinical AD, navigation impairment would appear early in AD, although it is overlooked. From animal and human studies, it has been known that critical components for a successful navigation include landmark recognition, egocentric route learning, and allocentric representation. Their corresponding neuroanatomical structures are lingual gyrus, posterior parietal lobe and hippocampus, respectively. Inferred from the theory of developmental psychology of Piaget concerning navigation and retrogenesis theory by Reisberg, AD patients would lose their navigation ability firstly in allocentric representation, followed by egocentric route learning and finally, landmark recognition. The anatomical regions involved in this sequence are compatible with the Braak-Braak stages for AD. Real life navigation tasks including the aforementioned 3 components were used to test this hypothesis. A total of 81 participants completed the study, including 21 normal subjects, 22 minimal cognitive impairment (MCI), and 38 eraly AD patients. MCI patients are supposed to represent a majority of preclinical AD. As predicted, early AD performed worst on all tasks. MCI patients performed worse than normal subject on egocentric route learning, which might be a good discriminator for MCI and normal. The manifestations of the three groups on three tasks are compatible with the hypothesis. Moreover, the different manifestation among group provides advise for early AD paitents and their care-givers.