Spatial-context memory in amnesic-mild cognitive impairment

• Main Authors: Wang,Hsuan-Min, 王宣閔
• Other Authors: 楊建銘
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/59588478484362359039

碩士 === 國立政治大學 === 心理學研究所 === 97 === Background: Amnesic mild cognitive impairment (a-MCI) was identified to have a high risk to become Alzheimer’s disease (AD). In early stage of AD, because of neurofibrillary tangles, patient began complaining progressive memory deficits. The progressive course of neurofibrillary tangles was divided into 6 stages (Braak and Braak, 1991). Initially, the neurofibrillary tangles destroyed perirhinal and parahippocampus neurons, which may correspond to the a-MCI stage and then proceed to hippocampal body that correspond to early AD. According to previous studies, the perirhinal is primarily associated with item features encoding, the parahippocampus associated with scene features encoding, and the hippocampus associated with spatial location memory. Based on these findings, we hypothesized that the item and scene features association memory would show impairments in a-MCI and the spatial location memory would not be impaired in a-MCI but in early AD. If the different stages could be discriminated by the performance on spatial context memory test that we design, it can be utilized in clinical settings to assist the diagnosis of a-MCI. Method: Three groups of subjects were selected from the clinic of the neurological department of Chang Gung Memorial Hospital, including normal subjects (n=30), a-MCI subjects not diagnosed with dementia (n=30), and mild AD subjects (n=30). All of them were administered a package of neuropsychological tests and a self-developed spatial context memory test that include three sub-tests: (1) a spatial location memory test: subjects have to recognize the location of a building that was appeared in a map; (2) an event-place association memory test: subjects need point out which spatial scene that was associated with this event; and (3) a place-object association memory test: subjects need point out which object that was associated with this place shown before. Result: In neuropsychological tests, a-MCI group demonstrated significant impairment in delay retrieval and memory retention in comparison to their performance on tests for other cognitive functions. The AD group showed decline in overall cognitive functions including declarative memory and others. In the spatial context memory test, both the spatial location memory test and the place-object association memory subtest showed a decline in a-MCI group, and a further decline in AD group; the event-place association memory test presented significant decreases in both a-MCI and AD group in comparison to normal control, but no difference between the two clinical groups. Conclusion: The current study shows that the spatial context memory in a-MCI patients has greater impairment than their general cognitive function. Compared with other screening test, the spatial context memory has greater sensitivity and specificity to discriminate a-MCI from NC.