MRI测量的海马、内嗅皮质体积与轻度认知障碍相关性的临床研究

目的 研究轻度认知障碍(mild cognitive impairment,MCI)与海马和内嗅皮质体积变化的相关性以及影响因素,探讨MRI测量海马和内嗅皮质体积鉴别MCI与认知功能正常(normal cognitive,NC)的价值.方法 从体检者中入选MCI组21例,NC组18名,进行一般情况评定、实验室检查和神经心理量表评测.应用MRI测量海马和内嗅皮质体积,并分析其与记忆功能的相关性;非条件logistic回归分析海马和内嗅皮质体积诊断MCI的特异性和敏感性;多重线性回归分析海马和内嗅皮质体积的影响因素.结果 MCI患者海马和内嗅皮质体积分别为(6.19±0.74)和(2.66±0.17)cm~3;显著小于NC组的(6.80±0.79)和(3.03±0.12)cm~3(P<0.05).海马体积与内嗅皮质体积显著相关(r=0.566,P<0.001);海马体积与临床记忆量表总分显著相关(r=0.430,P=0.04),内嗅皮质体积与临床记忆量表总分显著相关(r=0.722,P<0.001).应用海马体积区分MCI和NC的特异性为66.7%,敏感性为76.2%;应用内嗅皮质体积区分MCI和NC的特异性为88.9%,敏感性为90.5%.另外,海马体积与餐后2 h血糖(P<0.05)、收缩压(P<0.05)、舒张压(P<0.05)和血浆总胆固醇水平(P<0.01)呈负相关,而内嗅皮质体积则与之无关.结论 内嗅皮质和海马体积萎缩与记忆障碍密切相关,MRI测量的内嗅皮质和海马体积对MCI与NC的鉴别具有一定价值,而且内嗅皮质体积的特异性和敏感性优于海马体积.血压、血糖和血脂水平增高可能通过影响海马体积.     

Relation between hippocampal damage and cerebral cortical function in Alzheimer's disease

We investigated the relation between hippocampal damage and cerebral cortical dysfunction in Alzheimer's disease (AD) using MRI and SPECT. Nineteen patients with AD and 10 control subjects were studied. Hippocampal damage (including hippocampal formation, entorhinal cortex, and parahippocampal white matter) was assessed to evaluate the severity of atrophy and the magnetization transfer ratio (MTR) and cerebral cortical dysfunction was evaluated by quantitative cerebral blood flow (CBF) measurements using SPECT with 99mTc-ECD. Compared with controls, patients with AD had significantly more atrophy of the medial temporal lobe and a decrease in MTRs of the hippocampus and parahippocampus. There were significant correlations between the severity of hippocampal damage and regional CBF in temporoparietal lobes. Mini-Mental State Examination scores significantly correlated with the severity of hippocampal damage and regional CBFs in temporoparietal lobes. These results suggest that the functional effect of hippocampal damage occurs in temporoparietal lobes in AD, probably due to neuronal disconnections between hippocampal areas (including the entorhinal cortex) and temporoparietal lobes.     

轻度认知障碍患者多模态磁共振特征

目的 探讨轻度认知损害者(MCI)和阿尔茨海默病(AD)患者多模态磁共振成像特征与认知功能的关系.方法 共纳入9例遗忘型MCI,15例轻度AD及11例正常对照,以简明精神状况检查(MMSE)和认知功能筛查测验(CASI)评估总体认知功能,对高分辨率结构像进行基于体素形态学分析(VBM),测量扩散张量成像(DTI)图像、各脑区白质各向异性比值(FA)和平均表观弥散系数(ADC),分析脑结构萎缩及白质DTI指标与认知评分的相关性.结果 MMSE和CASI评分与颞、额、顶、扣带回、海马旁回等结构灰质体积改变呈正相关(P<0.001),MMSE和CASI总分与颞、顶叶以及海马旁回的FA值呈正相关,与ADC值呈负相关(P<0.05).结论 MCI和AD患者认知功能与颞、顶、海马旁回等脑区萎缩及白质微观结构损伤密切相关,多模态影像技术可作为认知损害脑机制研究的重要技术手段.     

A neuroradiological study on the influence of cerebral atrophy and white matter lesion on cognitive function in the elderly

We investigated the influence of brain atrophy and white matter lesions on cognitive function in elderly people. We selected 33 subjects (mean age, 79.2 +/- 5.1yrs) with a MMSE score from 14 to 30 who had no previous history of stroke from the outpatients in the Memory Clinic of our hospital. These subjects were divided into four groups on the basis of their MMSE score as follows: 14-20; moderate dementia (Moderate-D, n = 9), 21-23; mild dementia (Mild-D, n = 9), 24-27; mild cognitive impairment (MCI, n = 10), 28-30; normal (Normal, n = 5). Among these four groups, we compared the frequency of the associated risk factors for cerebral infarction (hypertension, diabetes mellitus, hyperlipidemia, heart disease), and the severity of brain atrophy and cerebral white matter lesion which were visually evaluated by MRI technique. Brain atrophy and white matter lesions were assessed by reviewing the cerebral cortex and hippocampus, and deep white matter lesion (DWML) and periventricular hyperintensity (PVH), respectively. Brain atrophy was divided into three grades (mild, moderate, severe) and white matter lesions were classified into four grades (0-3) using Fazekas's criteria. We performed statistical analysis to detect t parameters which correlate with and influence MMSE scores from among the MRI findings. The cases with dementia were all diagnosed as Alzheimer's disease. There were no significant differences among the four groups in mean age, the incidence of individual associated risk factors, the severity of cortical atrophy, or the grade of DWML (< or = 2) and PVH (< or = 2). However, the frequency of hippocampal atrophic change greater than a moderate grade increased in parallel with the exacerbation of reduced cognitive function (Normal; 20%, MCI: 40%, Mild-D; 56%, Moderate-D 89%), and approximately 76% with such a change were AD cases. Statistical analysis showed a significant negative correlation between the grade of hippocampal atrophy and MMSE score (r = -0.518, p < 0.005) and a great influence of hippocampal atrophy on that score (step-wise regression analysis: r = 0.518, p < 0.005). From the above results, it was suggested that more than moderate atrophic change in the hippocampus might possibly be related with cognitive impairment and that both DWML and PVH less than the second grade had little influence on the decline of brain function.     

轻度认知功能损害患者静息状态脑默认活动网络的功能磁共振研究

目的 采用静息状态功能磁共振(fMRI)技术,探讨轻度认知功能损害(MCI)患者的脑默认活动网络(DMN)是否存在异常及其可能的神经机制.方法 对20名遗忘型MCI老年患者和25名正常老年人进行简易智能状态检查(MMSE)、听觉词语学习测验(AVLT)和静息状态脑功能成像.利用低频振幅(ALFF)算法,观察MCI患者相对于正常老年人ALFF增强及减弱的区域.结果 MMSE和AVLT测试结果显示MCI患者与正常老年人比较,记忆功能损害较明显,主要以情景记忆的短延迟回忆[(2.4±1.7)分与(6.6±1.4)分,t=3.70,P＜0.01]和长延迟回忆[(2.1±1.6)分与(6.7±1.5)分,t=4.16,P＜0.01]损害为主.静息状态fMRI结果显示与正常老年人比较,MCI患者与情景记忆密切相关的海马、海马旁回和侧颞叶皮层等脑区的ALFF减弱(t=2.58、2.43、1.75,均P＜0.01),颞顶交界和顶下小叶的ALFF增强(t=3.14、2.77,均P＜0.01).结论 MCI患者静息状态DMN与情景记忆密切相关的脑区结点活动强度存在异常,与正常老年人比较,大多活动减低,但是部分区域活动增强,提示MCI患者脑内可能存在代偿机制.

Abstract：

Objective To explore the activity and its possible neural mechanism of brain default mode network by using resting state functional magnetic resonance imaging (fMRI) in patients with mild cognitive impairment (MCI). Methods The 20 amnestic MCI patients and 25 healthy controls were included in this study, and all subjects underwent mini-mental state examination (MMSE), auditory verbal learning test (AVLT) and fMRI. The data were analyzed by amplitude of low frequency fluctuation (ALFF), and the enhanced and weakened regions of ALFF were observed and compared in both MCI patients and healthy controls. Results MMSE and AVLT tests showed that the memory function was seriously impaired in MCI patients compared with healthy controls, which is based on the short and long delayed episodic memory impairment (2.4±1.7 vs. 6.6±1.4, t=3.70, P＜0.01; 2.1±1.6 vs. 6.7±1.5, t=4.16, P＜0.01). The resting state fMRI showed that MCI patients had significant decreases of ALFF in hippocampal formation, parahippocampal cortex and lateral temporal cortex as compared with health controls (t=2.58, 2.43 and 1.75, all P＜0.01), which were closely relevant to the episodic memory. And they had significant increases in temporal-parietal joint and inferior parietal lobule (t=3.14 and 2.77, both P＜0.01). Conclusions MCI patients show significant decreased active intensity of some DMN nodes that is related to episodic memory in resting state. Increased active intensity in MCI patients would be some type of compensation.     

首次发作晚发抑郁与轻度认知损害脑萎缩模式的比较研究

目的用优化的基于体素的形态学研究方法(VBM)比较首次发作晚发抑郁(LOD)与轻度认知功能损害(MCI)患者的脑萎缩模式,探索LOD患者脑结构与认知功能的关系。方法选择LOD、MCI及正常老人39例,分为LOD组9例,MCI组14例和NC组16例,用简易精神状态检查量表和认知功能筛检工具评估3组总体认知功能,跨文化神经心理成套测验评估不同领域认知功能。用VBM对颅脑高分辨率3D T_1WI进行分析。结果与NC组比较,LOD组双侧额叶、边缘系统和顶叶多个脑区明显萎缩(P<0.01)。与MCI组比较,LOD组双侧额叶和边缘系统多个脑区明显萎缩(P<0.01)。LOD组物品记忆功能评分与额叶和边缘系统多个脑区灰质体积呈正相关(r=0.49～0.76,P<0.01),言语流畅性评分与右侧颞上回呈正相关(r=0.72,P<0.01)。结论首次发作LOD患者认知相关的脑区灰质萎缩较MCI更广泛和明显;患者额叶与边缘系统灰质萎缩与认知下降相关。     

Memory enhancement by intrahippocampal, intraamygdala, or intraentorhinal infusion of platelet-activating factor measured in an inhibitory avoidance task.

Platelet-activating factor (PAF; 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine), which is thought to be a retrograde messenger in long-term potentiation (LTP), enhances glutamate release and LTP through an action on presynaptic nerve endings. The PAF antagonist BN 52021 blocks CA1 LTP in hippocampal slices, and, when infused into rat dorsal hippocampus pre- or posttraining, blocks retention of inhibitory avoidance. Here we report that memory is affected by pre- or posttraining infusion of the PAF analog 1-O-hexadecyl-2-N-methylcarbamoyl-sn-glycerol-3-phosphocholine (mc-PAF) into either rat dorsal hippocampus, amygdala, or entorhinal cortex. Male Wistar rats were implanted bilaterally with cannulae in these brain regions. After recovery from surgery, the animals were trained in step-down inhibitory avoidance or in a spatial habituation task and tested for retention 24 h later. mc-PAF (1.0 microgram per side) enhanced retention test performance of the two tasks when infused into the hippocampus before training without altering training session performance. In addition, mc-PAF enhanced retention test performance of the avoidance task when infused into (i) the hippocampus 0 but not 60 min after training; (ii) the amygdala immediately after training; and (iii) the entorhinal cortex 100 but not 0 or 300 min after training. In confirmation of previous findings, BN 52021 (0.5 microgram per side) was found to be amnestic for the avoidance task when infused into the hippocampus or the amygdala immediately but not 30 or more minutes after training or into the entorhinal cortex 100 but not 0 or 300 min after training. These findings support the hypothesis that memory involves PAF-regulated events, possibly LTP, generated at the time of training in hippocampus and amygdala and 100 min later in the entorhinal cortex.     

Anterior Hippocampal Volume Deficits in Nonamnesic, Aging Chronic Alcoholics

Magnetic resonance imaging was used to quantify the volume of the hippocampus in 47 men with chronic alcoholism and 72 healthy male control subjects. The subjects ranged in age from 21 to 70 years, thus permitting a test of whether older alcoholics suffer greater brain tissue volume reduction than do younger ones. Comparison brain regions included temporal lobe gray matter, white matter, and cerebrospinal fluid, as well as measures of the lateral ventricles, third ventricle, and temporal horns. The results of this cross-sectional study showed that the anterior, but not the posterior, portions of the hippocampus in both hemispheres were significantly smaller in the alcoholic than the healthy control group. Furthermore, the bilateral anterior hippocampal volume loss was greater in older than younger alcoholics. Despite the hippocampal volume deficit, these alcoholics did not demonstrate an explicit memory impairment; furthermore, memory test scores did not correlate significantly with hippocampal volumes. In the alcoholics, the age-related volume loss, which was over and above that expected in normal aging, was also evident in the temporal cortex and white matter. Likewise, alcoholic ventricular enlargement was age-related. Analysis of covariance revealed that the anterior hippocampal deficit persisted after accounting for the temporal lobe gray matter volume deficit. Multiple regression analysis revealed that the age-related brain volume abnormalities observed in the alcoholics could not be attributed to duration of alcoholism or total lifetime consumption of alcohol.     

Hippocampal atrophy as a surrogate of neuronal involvement in Fabry disease

Cerebral micro- and macro-vasculopathy have been described in Fabry disease (FD). Neuronal globotriaosylceramide accumulation in selective cortical and brain stem areas including the hippocampus has been reported by autopsy studies in FD, but clinical surrogates as well as the clinical relevance of these findings have not been investigated so far. We measured the hippocampus volumes in a group of clinically affected patients with FD and correlated the findings with the cognitive performance of the patients. Hippocampal volumes were determined manually on T1-weighted MR-images of 25 FD patients (age 36.5 ± 11.0 years) and 20 age-matched controls. Additionally, individual white matter (WM) and gray matter (GM) volumes were measured using brain segmentation analyses. After controlling for age, white matter lesion (WML) volume, and WM/GM-volumes hippocampal volumes were significantly decreased in FD. These findings were substantially more pronounced in a subgroup of men with FD. WM and WM/GM volumes, and memory function did not significantly differ between patients and controls. In patients with FD hippocampal volumes were neither significantly correlated to WML volume nor to WM or WM/GM volumes. Hippocampus atrophy was not driven by the WML or other brain tissue atrophy and seems to correlate with the neuronal involvement in FD. In this young to middle-aged Fabry cohort the hippocampus degeneration was functionally compensated without memory impairment. Longitudinal studies are needed to determine whether this degenerative component in FD will progress and, in concert with the individual WML-load, predict subsequent cognitive decline.     

脑白质疏松伴轻度认知功能障碍患者的弥散张量成像研究

目的研究脑白质疏松(LA)伴有轻度认知功能障碍(MCI)患者的脑白质弥散张量成像(DTI),分析LA伴MCI患者早期脑白质微观结构的变化与临床表现之间的关系。方法选取LA伴MCI患者31例(病例组),另选健康体检者27例(对照组),2组行常规头颅MRI及DTI扫描,并进行认知及心理检查,最后采用基于纤维束的空间统计方法分析2组之间部分各向异性(FA)值的差异。结果与对照组比较,病例组右侧新纹状体、内囊前肢、额叶眶皮质及深部白质,左侧中央前回、中央旁小叶及深部白质区域的FA值明显下降,差异有统计学意义(P<0.05)。结论 LA伴MCI患者的右侧新纹状体、内囊前肢、额叶眶皮质及深部白质,左侧中央前回、中央旁小叶及深部白质区域的白质纤维的完整性受到损害,且这些部位的损伤与患者的临床表现包括认知功能障碍、运动功能下降及泌尿功能障碍有关。     

Functional brain imaging of episodic memory decline in ageing

The episodic long‐term memory system supports remembering of events. It is considered to be the most age‐sensitive system, with an average onset of decline around 60 years of age. However, there is marked interindividual variability, such that some individuals show faster than average change and others show no or very little change. This variability may be related to the risk of developing dementia, with elevated risk for individuals with accelerated episodic memory decline. Brain imaging with functional magnetic resonance imaging (MRI) of blood oxygen level‐dependent (BOLD) signalling or positron emission tomography (PET) has been used to reveal the brain bases of declining episodic memory in ageing. Several studies have demonstrated a link between age‐related episodic memory decline and the hippocampus during active mnemonic processing, which is further supported by studies of hippocampal functional connectivity in the resting state. The hippocampus interacts with anterior and posterior neocortical regions to support episodic memory, and alterations in hippocampus–neocortex connectivity have been shown to contribute to impaired episodic memory. Multimodal MRI studies and more recently hybrid MRI/PET studies allow consideration of various factors that can influence the association between the hippocampal BOLD signal and memory performance. These include neurovascular factors, grey and white matter structural alterations, dopaminergic neurotransmission, amyloid‐Β and glucose metabolism. Knowledge about the brain bases of episodic memory decline can guide interventions to strengthen memory in older adults, particularly in those with an elevated risk of developing dementia, with promising results for combinations of cognitive and physical stimulation.     

Progressive entorhinal cortex lesions accelerate hippocampal sprouting and spare spatial memory in rats

Accelerating hippocampal sprouting by making unilateral progressive lesions of the entorhinal cortex spared the spatial memory of rats tested for retention of a learned alternation task. Subsequent transection of the sprouted crossed temporodentate pathway (CTD), as well as a simultaneous CTD transection and progressive entorhinal lesion, produced a persistent deficit on the memory task. These results suggest that CTD sprouting, which is homologous to the original perforant path input to the dentate gyrus of the hippocampus, is behaviorally significant and can ameliorate at least some of the memory deficits associated with hippocampal deafferentation.     

Prediction of cognitive decline in normal elderly subjects with 2-[(18)F]fluoro-2-deoxy-D-glucose/poitron-emission tomography (FDG/PET)

Neuropathology studies show that patients with mild cognitive impairment (MCI) and Alzheimer's disease typically have lesions of the entorhinal cortex (EC), hippocampus (Hip), and temporal neocortex. Related observations with in vivo imaging have enabled the prediction of dementia from MCI. Although individuals with normal cognition may have focal EC lesions, this anatomy has not been studied as a predictor of cognitive decline and brain change. The objective of this MRI-guided 2-[(18)F]fluoro-2-deoxy-d-glucose/positron-emission tomography (FDG/PET) study was to examine the hypothesis that among normal elderly subjects, EC METglu reductions predict decline and the involvement of the Hip and neocortex. In a 3-year longitudinal study of 48 healthy normal elderly, 12 individuals (mean age 72) demonstrated cognitive decline (11 to MCI and 1 to Alzheimer's disease). Nondeclining controls were matched on apolipoprotein E genotype, age, education, and gender. At baseline, metabolic reductions in the EC accurately predicted the conversion from normal to MCI. Among those who declined, the baseline EC predicted longitudinal memory and temporal neocortex metabolic reductions. At follow-up, those who declined showed memory impairment and hypometabolism in temporal lobe neocortex and Hip. Among those subjects who declined, apolipoprotein E E4 carriers showed marked longitudinal temporal neocortex reductions. In summary, these data suggest that an EC stage of brain involvement can be detected in normal elderly that predicts future cognitive and brain metabolism reductions. Progressive E4-related hypometabolism may underlie the known increased susceptibility for dementia. Further study is required to estimate individual risks and to determine the physiologic basis for METglu changes detected while cognition is normal.     

Minimal hippocampal width relates to plasma homocysteine in community-dwelling older people

BACKGROUND: The hippocampus is important for memory. Hippocampal atrophy and higher levels of homocysteine may both predict cognitive dysfunction in community-dwelling older people. We tested if higher homocysteine relates to hippocampal thinning in this group. SUBJECTS: 156 community-dwelling volunteers without clinical memory problems. METHOD: We measured minimal hippocampal widths on magnetic resonance images and homocysteine in plasma. RESULTS: Minimal hippocampal widths related inversely to homocysteine levels. CONCLUSIONS: Our results indicate that, even in healthy older people, homocysteine may damage the hippocampus. Reducing homocysteine levels in healthy older people may help to prevent Alzheimer's disease.     

遗忘型轻度认知损害基于体素的脑形态学研究

目的利用优化的基于体素的形态学研究方法,比较遗忘型轻度认知损害(aMCI)和轻度阿尔茨海默病(AD)患者脑灰质体积。方法选取aMCI患者9例(aMCl组)、轻度AD患者13例(AD组)和正常老年志愿者7例(对照组),经T_2加权像排除颅内存在白质高密度信号,对其进行高分辨率三维T_1加权像扫描,数据在参数统计软件包SPM5下进行头颅标准化、优化、分割和平滑等处理。结果 aMCI组的双侧颞上回、额中回、中央前回、扣带回、顶下小叶、左侧颞中回、中央后回、海马旁回、右侧岛回和旁中央小叶等结构灰质体积小于对照组,差异有统计学意义(P<0.01)。aMCI组的双侧颞上回、齿状回、额上回、额中回、岛回、左侧楔前叶、中央后回、右侧颞中回、颞下回、额下回、顶上小叶和海马旁回等结构灰质体积大于AD组,差异有统计学意义(P<0.01)。结论基于体素的形态学研究能够发现aMCI患者颞、顶、额叶均存在一定程度萎缩,其萎缩程度与累及范围均介于正常老人与轻度AD之间。     

Functional organization of the hippocampal memory system

In humans declarative or explicit memory is supported by the hippocampus and related structures of the medial temporal lobe working in concert with the cerebral cortex. This paper reviews our progress in developing an animal model for studies of cortical–hippocampal interactions in memory processing. Our findings support the view that the cortex maintains various forms of memory representation and that hippocampal structures extend the persistence and mediate the organization of these codings. Specifically, the parahippocampal region, through direct and reciprocal interconnections with the cortex, is sufficient to support the convergence and extended persistence of cortical codings. The hippocampus itself is critical to the organization cortical representations in terms of relationships among items in memory and in the flexible memory expression that is the hallmark of declarative memory.     

Neural basis of the cognitive map: path integration does not require hippocampus or entorhinal cortex

The hippocampus and entorhinal cortex have been linked to both memory functions and to spatial cognition, but it has been unclear how these ideas relate to each other. An important part of spatial cognition is the ability to keep track of a reference location using self-motion cues (sometimes referred to as path integration), and it has been suggested that the hippocampus or entorhinal cortex is essential for this ability. Patients with hippocampal lesions or larger lesions that also included entorhinal cortex were led on paths while blindfolded (up to 15 m in length) and were asked to actively maintain the path in mind. Patients pointed to and estimated their distance from the start location as accurately as controls. A rotation condition confirmed that performance was based on self-motion cues. When demands on long-term memory were increased, patients were impaired. Thus, in humans, the hippocampus and entorhinal cortex are not essential for path integration.     

Cerebral imaging and physiopathology of Alzheimer's disease

Alzheimer's disease (AD) is characterised by macroscopic cerebral damages which can be studied in vivo with neuroimaging techniques, even at the earliest stage. Studies were conducted in patients with amnestic Mild Cognitive Impairment (MCI) who best represent incipient AD. Right temporo-parietal hypometabolism, assessed by resting-state (18)FDG-PET, distinguishes patients who further develop AD from those who remain stable. From the pre-dementia stage of MCI, atrophy of the hippocampal region detected with structural MRI contrasts with functional alteration of the posterior cingulate gyrus measured with (18)FDG-PET and SPECT. Results from resting-state fMRI confirm this pattern of functional abnormalities and highlight changes in the hippocampal region functional connectivity, decreased with the posterior cingulate region, and increased with some frontal areas. Altogether with a structural connectivity impairment highlighted by DTI, those results support the hypothesis of a dysconnexion between the hippocampal and the posterior cingulate regions. Finally, activation fMRI data support the hypothesis of a functional compensation involving not only the frontal cortex but also, at the pre-dementia stage, the hippocampal region. Thus, this synthesis focuses on the hypotheses of dysconnexion and functional compensation, suggested to explain the discrepancies between the structural and functional alteration patterns, as well as on relevant results from resting-state fMRI, DTI and activation fMRI studies. Furthermore, this synthesis emphasizes the relevance of neuroimaging for the early detection of AD.     

遗忘型轻度认知损伤患者内隐和外显记忆的研究

目的　对遗忘型轻度认知损伤 (MCI)患者的内隐记忆和外显记忆进行研究。方法　为横断面研究 ,采用词语自由回忆、再认、自由联想和字根补笔的方法 ,分别测试 2 0例遗忘型MCI患者 (MCI组 )和 2 0例认知功能正常的老年人 (对照组 )的外显记忆和内隐记忆。结果　遗忘型MCI组存在语义性启动效应和知觉性启动效应 ,遗忘型MCI组较对照组外显记忆降低 ,而内隐记忆无显著差异。结论　遗忘型MCI患者的记忆功能呈外显记忆损害 ,内隐记忆保存的特点 ,这种记忆功能的双重性为MCI患者记忆功能康复训练提供了理论依据。     

对内嗅皮质和内侧颞叶萎缩的阿尔茨海默病与遗忘型轻度认知功能障碍患者的研究

目的探讨阿尔茨海默痛(AD)与遗忘型轻度认知功能障碍(aMCD)患者内嗅皮质和内侧颞叶萎缩(MTA)的关系。方法选择轻中度AD患者18例(AD组),aMC1患者1 7例(aMCI组)。认知功能通过长谷川痴呆量表修订版(HDS-R)和AD评定量表认知部分(ADAS-cog)评价。通过基于体素的AD特异性局部分析系统的Z评分来评价内嗅皮质的萎缩程度。同时视觉评分系统对MTA程度进行分级。结果 AD组HDS R评分明显低于aMCI组,ADAS-cog和MTA评分明显高于aMCI组(P<0.01)。AD组Z评分与MTA评分呈正相关(P<0.01)。aMCI组Z评分与年龄、MTA评分呈正相关(P<0.01),MTA评分与年龄呈正相关(P<0.05)。结论 aMCI患者中,内嗅皮质萎缩与认知功能改变相关;而AD患者中;MTA更可能的与认知功能相关。MTA评分比Z评分能更有效地区别aMCI和AD患者。在aMCI阶段,内嗅皮质萎缩起了主要的作用;而AD阶段海马等结构作用更突出。