False memory in patient with temporal lobe epilepsy
Date Issued
2006
Date
2006
Author(s)
Lin, Ching-Wei
DOI
zh-TW
Abstract
Literature shows that false memory manifestation results from an overdependence on semantic gist and/or impaired ability to monitor information. Schacter and co-workers claimed that the retention deficit of semantic gist information in amnesic and demented patients with Alzheimer’s disease (AD) is presumably due to lesions of mesial temporal lobe structures. Accordingly, the underlying neural substrates involving gist memory have been suggested to be associated with mesial temporal regions, while source monitoring function has been proposed to be related to frontal lobe function. However, neuropathological involvement of frontal regions in these amnesic and AD patients might confound the results of these false memory studies. Using patients with temporal lobe epilepsy (TLE) due to unilateral or bilateral mesial temporal sclerosis bearing brain-damaged locations restricted to medial portions of temporal areas, the present study was thus to examine the issue of whether the impaired retention of semantic gist materials is associated with mesial temporal dysfunction. Meanwhile, this study made an attempt to document neurocognitive functions in our Taiwan patients with TLE.
Forty-five patients with TLE (16 left, 15 right, and 14 bilateral) and 22 healthy controls participated in the study. The inclusion criteria for patients with TLE consisted of: (1) EEG abnormalities restricted to the temporal lobes; (2) no lesion other than mesial temporal lobe sclerosis on brain MRI; (3) no history of brain surgery; and (4) no physical and psychiatric illness. Normal control subjects were also free of neurological and psychiatric disorders. All subjects were given the false memory task and a battery of neurocognitive tests.
The results revealed that left and bilateral TLE patients evidenced a significant deficit of delayed verbal and visual episodic and semantic memory function compared to their normal control counterparts, even after controlling for VIQ while only defective semantic memory manifested in right TLE patients. However, only bilateral TLE patients evidenced a low level of false memory functioning. Further data analysis revealed that a low level of false memory manifestation in bilateral TLE patient seemed to be related to a failure to retain gist information.
Based on the present results, it appeared that bilateral mesial temporal structures might play an important role in gist memory functioning. These findings thus seemed further corroborate Schacter and colleagues’ claim. However, a caveat should be taken with care for interpreting the present results because only half of bilateral TLE patients did evidence lesions of mesial temporal lobes merely based on MRI rather than on both EEG and MRI findings. Thus, the issue of whether abnormal EEG sites other than temporal areas might affect false memory functioning remains unclear and awaits further investigation.
Subjects
顳葉癲癇患者
內側顳葉結構
錯誤記憶
要旨記憶
Temporal lobe epilepsy
mesial temporal lobe structure
false memory
gist memory
Type
other
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