碩士 / 國立成功大學 / 行為醫學研究所 / 101 / As the phenomenon of an aging demographic structure reveals a senile society, the population concerned with Alzheimer’s disease (AD) increases rapidly. The prevalent core syndrome of AD is the irreversible defect of the patients memory. According to long-term pathological development of AD, the episodic memory impairment in AD patients becomes more salient than other cognitive syndromes, it is a syndrome of early stage development. In 1985, Tulving proposed the terms “mental time travel” and “re-experience”, stating that episodic memory is strongly related to the hippocampus. According to the empirical research findings of neuro-imaging imagination is a result of a stimulated index in the posterior visual cortex interacting with the memory traces in the left parahippocampus. Besides, during the core network of elaboration/fMRI, brain images show that when AD patients proceed to imaging and recalling, the activation areas in human brains overlap. For instance, the activated precuneus areas are close to the activated retrosplenial cortex. To imagine future scenarios or to obtain the ability of future imagining of actual and imaginary events, one is required to think of ones individual past experiences.
This study was aimed to test mainly hypotheses for AD patients of different pathological stages against people of normal capability. First to examine the ability to simulate personal future events; Second, recalling events from alternative perspectives, Third, imagining imaginary events. Emulating past studies that use pictures as cues to remember former events or future thinking, this study adopted the same methodology. At some points after the first trial, participants were asked to recall events from the past. After these experiments, we categorized the contents of transcripts into internal and external components.
Participants were patients with very mild (CDR 0.5) and mild AD (CDR 1.0) from an Alzheimer’s Disease Research Center and the age-/sex-matched cognitively healthy controls (HC). 31 AD patients (15 males, mean age 72, education 10 years, MMSE 23, CASI 77) and 31 HC (16 males, mean age 69, education 11 years, MMSE 27, CASI 92) completed the study. No difference was detected between those two groups in terms of basic visual perceptual, verbal fluency and listening comprehension abilities, even though AD had a poorer semantic verbal fluency.
The interviews were segmented, categorized and then rated according to the AMI procedure. Subsequent analysis on inter-rater reliability of scoring indicated high agreement (Pearson’s r = .91). The number of internal and external details were counted and summed up across the three trials for each subject. All of events were analyzed using a 2 (group, AD and HC) × 2 (temporal direction, past and future) × 2 (details, internal and external) repeated factorial ANOVA. AD patients exhibited less internal episodic details as compared with HC, in both of the personal memory recollection (t(60)= -3.224, p 〈 .005) and personal imagination (t(60)= -2.083, p 〈 .005) experiments. Moreover, compared to the sum of internal and external details of both groups, the result for the experiment on memory recollection is higher than for imagination (F(1,60) = 16.559, p 〈 .005). Otherwise, the results of AD were worse than HC for recalling events from alternative perspective (F(1,60) = 5.261, p 〈 .05). By contrast, AD showed no significant difference with HC in imagining imaginary events (F(1,60) = 2.849, p =.097).
Compared to HC, AD reproduced more external semantic details when remembering personal past as well as imagining personal future events, and less internal episodic details in both remembering and imagination. It confirmed the hypothesis of episodic simulation. Moreover, both HC and AD produced more semantic and episodic details in remembering past events than in imagining the future, indicating that imagining is more difficult than recalling. AD, are unable recalling life events from alternative perspectives. It was parallel with recalling others experiences involved higher cognitive functions that have impaired in early AD apparently. Lastly, the ability of imaging imaginary events were no different, supposed that ageing HC also experienced difficulty in imagining and those brain locations in AD were complete.
Lastly, we lack brain scans of participants to assess the extent and the loss of relevant location.
| Identifer | oai:union.ndltd.org:TW/101NCKU5666009 |
| Date | January 2013 |
| Creators | YiLin, 林宜 |
| Contributors | Ming-Chyi Pai, 白明奇 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 103 |
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