Memory Monitoring In Amnestic Mild Cognitive Impairment

Objective Memory monitoring process is a metamemory component consisting of the individual's subjective assessment of his or her own memory ability for encoding and retrieve, which is beyond the memory. Subjective memory complaint is important in diagnosis of amnestic mild cognitive impairment (aMCI). The central purpose of this study was to investigate the memory monitoring ability in aMCI via a specific experi-mental feeling-of-knowing (FOK) task, to find out how aMCI patients estimate their own memory capability. Also, the study want to search the possible reason of aMCI's memory disturbance. The result maybe useful for diagnosis earlier Alzheimer's Disease (AD) , which convert from aMCI.Methods 30 people with aMCI and 30 health controls which matched with aMCI at age,gender and education were administered with a neuropsychological battery and memory monitoring test. The FOK judgement which consists in asking subjects to esti-mate the likelihood that they will later recognize a piece of information they had just failed to recall with a cue, was used as memory monitoring task, including episodic memory FOK and semantic memory FOK. The results of episodic memory (EM) and semantic memory (SM) were the unrecall sum in FOK procedure.Results1.In a neuropsychological battery, the Rey-auditory verbal learning test (RAVLT) was used to test patients'objective memory, including immediate and delayed recall. Com-pared with health controls (5.6±1.0,8.3±1.7) , aMCI patients were impaired both in immediate recall (3.4±0.8) and delayed recall (3.8±2.2), furthermore impaired in de- layed recall more significantly(P<0.001).2.Compared with health controls (EM, 8.1±2.0;SM, 5.0±1.4), aMCI patients'were impaired in EM (13.7±2.8,t=8.97,Р<0.01), but not significantly impaired in SM (5.4±1.4,t=1.43,Р>0.05).3.The FOK judgement has four kinds results, respectively a:'yes'judgement associated with correct recognition;b:'yes'judgement associated with incorrect recognition;c:'no'judgement associated with correct recognition;d:'no'judgement associated with incorrect recognition. In episodic memory FOK, the aMCI patients compared with health control have difference at a (respectively 58±13 and 72±12) and b (respectively 42±13 and 28±12 ) (t=-4.27,4.27,Р<0.01), but no variance in c and d (t=0.71,-0.71,Р=0.48). There was no difference in performance of semantic memory FOK in four kinds results.Conclusions These results show that aMCI patients with SMC have significantly impaired in objective memory, especially delayed recall. Meanwhile, the aMCI patients made less accurate memory monitoring than the healthy control by overestimating their own memory performance on episodic memory FOK,whereas the semantic memory monitoring is not impaired,which is coincident with impairment of EM and SM in aMCI.This outcome indicates that the deficit of memory monitoring in aMCI may be the foundation of subjective memory complaints and useful for aMCI's diagnosis.It's also indicates the change of memory monitoring in aMCI maybe useful for predicting aMCI whether convert to AD.