早期Alzheimer病的认知与社会功能的动态观察

目的 :探讨Alzheimer病早期的认知损害与社会功能缺损的特点及相互关系。方法 :对 2 2例早期Alzheimer病患者进行 3个月的观察 ,采用智能筛检测验和功能活动问卷作认知及社会功能活动评估 ,同时与 12例同期的老年期抑郁症患者进行对照。结果 :Alzheimer病患者的认知测验在短时记忆、注意能力、数字计算、抽象判断、思维流畅等因子评分降低更明显 ,而测试所消耗的时间相对较短 ;社会功能活动也以自行购物、了解新鲜事物、记得约定等方面评分较高。治疗后无显著改善。结论 :Alzheimer病患者某些方面的认知功能早期就有显著下降 ,相应的社会功能缺损也较明显     

载脂蛋白E基因多态性与Alzheimer病的关系探讨

目的：探讨Alzheimer病（Alzheimer disease,AD)患者的载脂蛋白E(apolipoproteinE,APOE)基因的分布，及其相关性。方法：利用聚合酶链反应－限制性片段长度多态性（PCR－RFLP）技术对AD患者和相应健康对照的APOE基因进行分型，从而进行AD与APOE等位基因多态性的关联分析。结果：AD病人APOE等位基因。ε4占20．74％，明显高于正常人对照组的7．64％，而ε3则占64．63％，低于正常人对照组的84．12％。结论：APOE等位基因中，ε4可能为AD的易患因子，而ε则为保护因子。     

语义性痴呆:一例汉语病人的个案研究

目的：分析一例语义性痴呆(Semantic Dementia，SD)患者的神经心理特征。方法：针对一例大学文化程度的SD患者完成一系列神经心理测验和头颅核磁共振(MRI)及氙CT(XeCT)检查。结果：1．语义记忆的选择性损害引起严重的失命名、对口语和书写的词语理解受损、言语流畅性测验表现差以及一般知识的储存丧失；2．语言表达和理解的其他成分相对保持；空间知觉、执行功能和非言语的解决问题能力正常；情景记忆相对保存；3．阅读障碍呈表层失读模式；4．MRI和XeCT提示患者左颞叶新皮层呈现局限性严重萎缩。结论：汉语文化背景的SD患者的认知特征与西方的结果相似，左颞叶新皮层萎缩导致选择性的语义记忆损害。     

轻度认知损害的研究进展

随着社会人口的老龄化，老年性痴呆（Alzheimer’disease，AD）已引起越来越多的重视。轻度认知损害（mild cognitivei mpairment，MCI）是界于正常老年和痴呆之间的一种认知功能损害状态。近年研究发现MCI向AD的演化率大约每年为12％左右，该比率较普通人群中痴呆发生率约高10倍，因此，MCI患者存在较高发生痴呆的危险性。研究表明：MCI患者中10％～15％在1a内，40％在2a内，53％在3a内，100％在5a内进展为痴呆。因此，早期确诊MCI为AD的早期提供一个最佳治疗时间窗，预防和推迟AD的发生。     

Alzheimer病与Parkinson病患者记忆损害的比较研究

目的：测查Alzheimer病、Parkinson病患者的记忆功能，了解这两种疾病病人记忆损伤的特征。方法：采用多维记忆评估量表中的12个分测验对30例原发性Parkinson病患者、30例临床诊断可能的Alzhdmer病患者及年龄、性别和教育程度与2个病人组相匹配的2个正常对照组进行外显记忆、内隐记忆及日常生活记忆等记忆功能的评定。结果：AD组在所有的分测验和记忆因子上均差于对照组；PD组在图画再认、数字广度、汉词回忆、图形再生、经历定向等分测验和记忆广度、再认记忆、自由回忆、日常记忆、外显记忆等记忆因子上均显著低于对照组：经以教育年限为协变量校正后发现。除自由组词、残图命名、数字广度、空间广度、汉词回忆、常识记忆、记忆广度、内隐记忆外，AD组在其余各分测验和记忆因子上均存显著差于PD病人组。结论：AD病人存在着广泛的记忆功能障碍：PD病人存在着工作记忆和策略记忆的障碍：两者的记忆功能障碍存在着明显的不同。     

老年精神分裂症与阿尔茨海默病智力及记忆功能的对照研究

目的：比较老年精神分裂症与阿尔茨海默病（AD）患者的智力及记忆功能，方法：采用韦氏成人智力量表及韦氏记忆量表对69例老年精神分裂症和25例AD患者进行了测试。结果：AD和老年精神分裂症患者都有不同程度的智力及记忆功能障碍，但AD患者的智力及记忆功能损严重程度明显较老年精神分裂症为重。尤其是AD患者的言语理解及记忆／不分心的功能更为低下，短时记忆障碍为明显，而语义忆受损严重程度同老年精神分裂症相比，差别无显著性意义，结论：老年精神分裂症患者的智力及记忆损害不同于AD患者，有一定的特征性，提示老年精神分裂症同AD智力及记忆障碍的差别在于各自的神经生物学病理机制的不同。     

Alzheimer病和血管性痴呆患者血清β-AP的检测

目的：探讨血清中β淀粉样蛋白（β-amyloid protein,β-AP）的含量,对Alzheimer病（AD）和血管性痴呆（VD）的诊断价值。方法：采用放射免疫分析法,检测临床诊断为AD患者9例,VD患者16例,及68例缺血性脑血管病（ICVD）患者血清β－AP的含量,同时与对照组比较。结果：AD与VD患者β-AP含量明显高于ICVD组和对照组,且呈显著性差异（P＜0．01）,ICVD患者的β-AP含量也明显高于对照组（P＜0．05）,结论：β-AP含量增高是AD和VD病发病的危险因素,β-AP的检测为早期诊断和防治老年性痴呆有着重要的参考价值。     

ADAS-Cog中文版区分轻、中度阿尔茨海默病的能力

目的：探讨阿尔茨海默病评定量表认知部分(ADAS-Cog)中文版区分轻、中度AD的能力。方法：199例轻度和106例中度AD患者为研究被试(符合NINCDS-ADRDA很可能AD诊断标准),对所有被试进行ADAS-Cog中文版测试。结果：中度AD患者ADAS-Cog总分及各条目评分明显高于轻度AD被试,GLM分析提示ADAS-Cog评分不受被试年龄与受教育程度的影响,ADAS-Cog能有效反映轻、中度AD患者不同的认知损害模式而不依赖于被试的学历。Logistic回归分析定向力和结构性练习条目评分及ADAS-Cog总分能有效区分轻、中度AD,敏感度为78％-82％,特异度为70％-73％。结论：ADAS-Cog中文版对轻、中度AD具有较好的区分能力,推荐将该量表用于评估药物对中国AD患者认知功能的疗效。     

轻度认知功能障碍和不同程度Alzheimer病患者认知功能与内颞叶结构体积的关系

目的：研究轻度认知功能障碍（mild cognitive impairment，MCI）和不同程度阿尔茨海默病（Alzheimer disease，AD）患者的认知功能与内颞叶结构体积的相关关系。方法：16例MCI、20例轻度AD和19例中重度AD患者分别接受临床评估、神经心理学检查和头颅核磁共振（MR）扫描，在重建的图像上测量杏仁核、海马、内嗅皮质及颞角的体积并行标准化处理，然后对神经心理学指标与内颞叶结构MR指标进行相关性分析。其中神经心理学检查包括简易精神状态检查量表（mini mental state examination，MMSE）和无意义图形再认、逻辑记忆、数字广度、延迟回忆、画钟测验、词语流畅性测验及日常生活行为量表。结果：三组间各结构MR标化体积除左、右颞角外差异均无统计学意义（P〉0．05）。在MCI组中，注意力计算力、数字广度测验得分与左侧杏仁核体积负相关（r=-0．51～-0．57，P〈0．05），无意义图形再认得分与右侧海马体积正相关（r=0．77，P〈0．001）；在轻度AD组中，MMSE总分、无意义图形再认得分与杏仁核体积正相关（r=0．46～0．55，P〈0．05）；在中重度AD组中，定向力得分与右侧内嗅皮质体积正相关（r=0．47，P=0．041）。结论：无意义图形再认和数字广度测验等与内颞叶结构MR体积之间存在中度相关关系；杏仁核在AD的发展过程中可能起着更萤要的作用。     

阿尔茨海默病与载脂蛋白E基因-427C/T多态性的关联研究

目的 探讨上海地区汉族人群载脂蛋白E(apolipoprotein E，apoE)基因启动子区—427C／T多态性与Alzheimer病(Alzheimer's disease，AD)发病风险的关系。方法 采用聚合酶链反应和限制性片段长度多态性方法，在104例AD患者和110名正常人中检测了apoE基因—427C／T各基因型及基因频率的分布。按比值比(odds ratio，0R)作疾病关联分析。结果 (1)AD患者与正常对照人群之间不存在—427C／T各等位基因和基因型频率分布的差异(P＞0．05)；(2)按apoE ε4基因分层后，无论是ε4型人群还是非ε4人群都不存在AD患者与正常老人间多态分布的差异(P＞0．05)；(3)在—427C／T 3种基因型中，仅T／T型AD与apoE ε4等位基因呈正关联(OR＝3．94，95％CI：2．206—7．038，x^2＝21．48，P＜0．05)。结论 上海地区汉族人群中，apo E基因—427C／T多态不是AD的疾病易感因子。     

Conceptual implicit memory performance in Alzheimer's disease.

Alzheimer's disease (AD) patients often exhibit deficits on conceptual implicit memory tests such as category exemplar generation and word association. However, these tests rely on word production abilities, which are known to be disrupted by AD. The current study assessed conceptual implicit memory performance in AD patients and elderly control participants using a conceptual priming task that did not require word production (i.e., semantic decision). Memory performance was also examined using a category exemplar generation test (i.e., a conceptual priming task that required word production) and a recognition memory test. AD patients exhibited deficits on the semantic decision task, the category exemplar generation task, and the recognition memory task. The results indicate that the conceptual memory deficits observed in AD patients cannot be attributed completely to word production difficulties.     

The hyperpriming phenomenon in normal aging: a consequence of cognitive slowing?

Increased semantic priming effects (hyperpriming) are sometimes observed in Alzheimer's disease (AD) and in normal aging. Whereas the processes underlying this phenomenon are now well understood in AD, the interpretation is much more woolly in normal aging. To explore semantic priming, the authors used a lexical decision task in which the influence of attention and cognitive slowing was controlled. To explore the semantic organization, the words had coordinate (tiger-lion) or attribute relations (zebra-stripes). Priming scores of 21 older and 20 young participants were equivalent in the 2 conditions. These results reflect the integrity of semantic memory with normal aging and call into question some investigations showing hyperpriming for older participants; this may instead be an artifact of a general slowing effect.     

Implicit and explicit memory in children with congenital and acquired brain disorder

Implicit and explicit memory were examined in 8- to 15-year-old children with myelomeningocele and shunted hydrocephalus, severe traumatic brain injuries, or orthopedic injuries. Each group included between 22 and 29 children. Children completed a fragmented picture identification task to assess perceptual priming and a semantic decision-making task to assess conceptual priming. Each task also assessed procedural learning as well as explicit recall and recognition. All 3 groups showed significant perceptual and semantic priming of similar magnitude. In contrast, both brain-disordered groups displayed poorer explicit memory than did the comparison group. No group showed significant procedural learning on either task. Age and IQ were stronger predictors of explicit recall than of implicit memory. The findings indicate that implicit memory is relatively intact in many children with congenital and acquired brain disorders, despite deficits in explicit memory, and support the existence of separate memory systems in children.     

Evidence for a dissociation between perceptual and conceptual priming in Alzheimer's disease

The status of perceptual priming and word-completion priming in patients with Alzheimer's disease (AD) was examined. Experiment 1 established the reliability of the perceptual priming measure in normal subjects. In Experiment 2, AD patients showed a normal magnitude of perceptual priming. In Experiment 3, a single group of AD patients showed a normal magnitude of perceptual priming and impaired word-completion priming. Further, word-completion priming, but not perceptual priming, was correlated with verbal fluency performance in AD. These results suggest a dissociation between two components of verbal priming. Perceptual priming may reflect the operation of a structural-perceptual memory system mediated by occipital lobe regions relatively spared in AD. Word-completion priming may reflect the operation of a lexical-semantic memory system mediated by temporoparietal lobe regions compromised in AD.     

The differentiation of semantic dementia and frontal lobe dementia (temporal and frontal variants of frontotemporal dementia) from early Alzheimer's disease: a comparative neuropsychological study

The authors compared age-matched groups of patients with the frontal and temporal lobe variants of frontotemporal dementia (FTD; dementia of frontal type [DFT] and semantic dementia), early Alzheimer's disease (AD), and normal controls (n = 9 per group) on a comprehensive neuropsychological battery. A distinct profile emerged for each group: Those with AD showed a severe deficit in episodic memory with more subtle, but significant, impairments in semantic memory and visuospatial skills; patients with semantic dementia showed the previously documented picture of isolated, but profound, semantic memory breakdown with anomia and surface dyslexia but were indistinguishable from the AD group on a test of story recall; and the DFT group were the least impaired and showed mild deficits in episodic memory and verbal fluency but normal semantic memory. The frontal and temporal presentations of FTD are clearly separable from each other and from early AD.     

Processing of semantic relations in normal aging and Alzheimer's disease.

The decline in semantic memory observed in Alzheimer's disease is presumed to result from progressive loss of the attributes underlying category representation. Here, we explored the possibility that semantic deterioration would affect attributes differently, depending on the type of semantic relationship connecting the subject and the object of the attribution. We compared the performance of 50 patients with probable Alzheimer's disease (APs) to that of 30 elderly controls in two semantic tasks: a verbal sentence verification task and a visual test of analogical relations, both including several types of semantic relations. On the sentence verification task, the performance of APs was comparable to that of elderly controls when statements were true, but deteriorated significantly when statements were false. This result was interpreted as a failure of controlled processes to successfully search semantic space when statements were incongruent or false. In addition, all participants found some semantic relations more difficult to process than others, with relative difficulty being consistent across tasks. Taxonomic semantic relations were the most difficult, while part/whole relations were the easiest, but also the ones to deteriorate most rapidly. In contrast, functional attributes were comparatively preserved as the disease progressed. These results emphasize the role of attention and semantic context in jointly determining access to relevant attributes and categories. Furthermore, they suggest that semantic memory impairments in Alzheimer's are affected by the type of processing and semantic relationship required by the task.     

Implicit memory for words presented in short texts is preserved in Alzheimer's disease

BACKGROUND: The level of efficiency of implicit memory in Alzheimer's disease remains unclear as previous studies using stem completion tasks have led to contradictory results. METHOD: The present study used target words embedded in significant short texts that subjects were required to read aloud (i.e. to enhance semantic processing). Texts were presented in two perceptual situations: 'simple' (blank spaces delimitating words) and complex' (spaces were filled by '8's). In the completion phase, patients had to write the first word that came to mind in order to complete a three-letter stem. The recognition phase explored explicit memory performance. The performance of 24 Alzheimer patients was compared to a matched sample of healthy controls. RESULTS: Reading times differed between groups and were shorter for healthy controls. Recognition was dramatically lower in patients, thus confirming the alteration of explicit memory in this pathology. However, a significant priming effect (e.g. the tendency to complete the stem with the aid of a previously explored word) was present in both groups and did not differ between patients and healthy controls. CONCLUSIONS: The absence of a correlation between priming and recognition scores suggests that this result cannot be explained by an explicit memory bias. Moreover, as the priming level was identical whatever the perceptual aspect of the text, we suggest that the priming effect is not only mediated by perceptual processes but also by lexical and conceptual processes, which to some extent are preserved during the light and moderate stages of this disease.     

Cognitive estimation impairment in Alzheimer disease and mild cognitive impairment

Intact executive functioning is believed to be required for performance on tasks requiring cognitive estimations. This study used a revised version of a cognitive estimations test (CET) to investigate whether patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI) were impaired on the CET compared with normal elderly controls (NECs). Neuropsychological tests were administered to determine the relationship between CET performance and other cognitive domains. AD patients displayed impaired CET performance when compared with NECs but MCI patients did not. Negative correlations between tests of working memory (WM) and semantic memory and the CET were found in NECs and AD patients, indicating that these cognitive domains were important for CET performance. Regression analysis suggests that AD patients were unable to maintain semantic information in WM to perform the task. The authors conclude that AD patients display deficits in working memory, semantic memory, and executive function, which are required for adequate CET performance.     

Task Complexity and Signal Detection Analyses of Lexical Decision Performance in Alzheimer's Disease

This experiment addressed the issue of whether the changes in semantic memory performance associated with Alzheimer's disease (AD) could be distinguished from a generalized cognitive slowing. Young adults, healthy older adults, and AD patients performed 3 different reaction time (RT) tasks involving yes-no responses to visually presented letter strings. Task complexity analyses indicated that performance in the semantic task (lexical decision) was consistent with a generalized slowing of cognitive function that was greater in magnitude for AD than for normal aging. Signal detection analyses of the lexical decision data demonstrated AD-related changes in word-nonword discrimination, response bias, and the relation between discrimination and RT. The general cognitive slowing associated with AD was accompanied by additional changes specific to the performance of this semantic memory task.     

Conceptual priming in semantic dementia: A window into the cognitive and neural basis of conceptual implicit memory

The present study examined the impact of impairment in semantic memory on conceptual repetition priming by means of the longitudinal study of a patient with semantic dementia. ST was tested in four consecutive years, during which his semantic memory progressively deteriorated. On each occasion, he performed an abstract/concrete verification task and a verb generation task. In both of these tasks, performance during a test phase was compared for stimuli previously processed in a study phase and stimuli first seen in the test phase. Control subjects showed priming, as indicated by faster responses to studied than to baseline stimuli. ST showed intact priming that was of normal magnitude in the first two years of testing, but failed to show priming in the subsequent two years of testing. This pattern of results is interpreted with reference to the differential decline of item-specific and superordinate knowledge. The implications of these findings for the neural basis of conceptual priming are also discussed.