创新背景

根据统计，美国超过600万人患有阿尔兹海默症，会丧失记忆和认知功能，逐渐难以完成日常任务。阿尔兹海默症在目前的医疗水平状况下是无法被治愈的，只能依靠药物缓解一些症状。记忆在识别气味时有着至关重要的影响，研究人员发现嗅觉和痴呆有着一定关系，因为受阿尔茨海默病影响的组织特征的斑块和缠结通常先出现在嗅觉和记忆相关区域，然后在大脑的其他部位发展。但目前尚不明确阿尔兹海默症带来的大脑损伤是否会真的导致嗅觉功能变化。

创新过程

从识别食品的味道到检测烟雾等危险识别，嗅觉为人的大脑提供着关键信息。芝加哥大学医学院的研究人员通过对515名老年人进行纵向研究，并利用1997年开始的一个研究衰老和神经退行性疾病等慢性病的项目——拉什大学记忆与衰老项目（MAP）的匿名患者数据，发现嗅觉功能随着时间推移下降，不仅预示认知功能退化丧失，还预测着阿尔兹海默病等脑部疾病重要的大脑区域的结构变化。

MAP参与者是居住在伊利诺伊州北部退休的老年人，每年会接受一次检测，跟踪确定他们识别某些气味的嗅觉状况，认知功能和痴呆症迹象，以及其他健康参数，一些参与者还接受了MRI扫描。对515名老人的纵向研究可能促使气味测试筛查发展，帮助检测患者认知障碍的时间提前。
研究结果说明嗅觉的快速下降情况是大脑特定区域在结构上发生的最终事情的一个很好的指标。随着时间的推移，比起嗅觉能力正在缓慢下降或保持正常嗅觉的人，嗅觉迅速下降的人的认知功能状况会更糟糕，并且患有大脑问题甚至阿尔兹海默症的可能性更高。

研究人员发现，在正常认知期间，一个人的嗅觉功能迅速下降预示着阿尔兹海默病的多种特征的出现，包括与嗅觉和记忆相关的大脑区域灰质体积变小，认知能力下降。出现这些症状的老年人患痴呆症的风险更高。因为嗅觉丧失的风险类似于携带APOE-e4基因，它与晚期发病的阿尔兹海默病的风险增加有关，是发病的已知遗传风险因素。
脑部变化以嗅觉区域最为明显，包括杏仁核和内嗅皮层。内嗅皮层位于海马结构、海马支脚和海马旁回附近，是海马体的主要输入，对生物的记忆和导航起着重要的作用，而海马体是阿尔兹海默病的关键部位。研究人员表示，与嗅觉下降不太严重的人相比，嗅觉迅速下降的人的嗅觉和记忆相关区域中的灰质的体积和形状更小。

研究团队希望通过检查脑组织中阿尔兹海默氏症的标志物来扩展研究发现，期望能在诊所使用类似听觉和视觉的检测方式，开发筛查追踪老年人早期痴呆症迹象的手段和治疗方法。修苦厄测试方便链家，在一系列外观类似于毡尖笔的棍子中注入独特的香味，要求每个人从一组四种选择中识别出来。
如果嗅觉测试能识别早期患病风险较高的人群的状况，如40至60岁及其以上的人，将能够有足够的信息纳入临床试验并开发更好的药物。研究人员表示，必须在对阿尔兹海默氏症的所有风险因素的背景下进行研究，考虑饮食和运动的影响。嗅觉和嗅觉的变化应该是影响大脑健康和衰老的一系列因素的重要组成部分。研究将进一步扩大对象范围，拓展关于大脑结构变化相关的数据，进一步探索嗅觉变化与其他身体机能之间的关系。

创新关键点

通过嗅觉和记忆之间的关系探索嗅觉变化与大脑结构变化以及阿尔兹海默症之间的联系。

创新价值

拓展检测脑部疾病和认知功能障碍的方法，或可帮助开发新的治疗方法和药物。

Loss of smell or indicative of decreased cognitive function

From identifying the taste of food to detecting hazards such as smoke, smell provides critical information to the human brain. Researchers at the University of Chicago School of Medicine, using a longitudinal study of 515 older adults and using anonymous patient data from the Rush University Memory and Aging Project (MAP), a project that began in 1997 to study chronic diseases such as aging and neurodegenerative diseases, found that a decline in olfactory function over time not only predicts cognitive decline loss, but also predicts structural changes in brain regions important to brain diseases such as Alzheimer's disease.

MAP participants, retired seniors living in northern Illinois, were tested annually to track their olfactory status, cognitive function and signs of dementia, as well as other health parameters, to identify certain odors, and some participants also underwent MRI scans. A longitudinal study of 515 elderly people may have led to the development of odor test screening, helping to detect cognitive impairment in patients earlier.

The findings suggest that a rapid decline in smell is a good indicator of the final thing that happens structurally in specific areas of the brain. Over time, people with a rapidly declining sense of smell have worse cognitive function and are more likely to have brain problems or even Alzheimer's disease than people whose sense of smell is slowly declining or maintain a normal sense of smell.

The researchers found that a person's rapid decline in olfactory function during normal cognitive periods heralded the emergence of multiple characteristics of Alzheimer's disease, including smaller gray matter volumes in brain areas associated with smell and memory, and decreased cognitive abilities. Older adults who develop these symptoms are at higher risk of developing dementia. Because the risk of olfactory loss is similar to carrying the APOE-e4 gene, it is associated with an increased risk of advanced-onset Alzheimer's disease and is a known genetic risk factor for the onset of morbidity.

Brain changes are most pronounced in olfactory regions, including the amygdala and the endococcal cortex. The endothorphal cortex, located near the structure of the hippocampus, the feet of the hippocampus, and the paracycampus of the hippocampus, is the main input to the hippocampus and plays an important role in the memory and navigation of organisms, which is a key site of Alzheimer's disease. The researchers said that people with a rapidly decreased sense of smell had smaller size and shape of gray matter in areas associated with smell and memory compared to people with less severe loss of smell.

The research team hopes to expand the findings by examining markers of Alzheimer's in brain tissue, expecting to develop screening methods and treatments to track early signs of dementia in the elderly using auditory and visual tests in clinics. The Shukuge tests the convenience chain home, infused with a unique scent in a series of sticks that look like felt-tip pens, requiring each person to identify from a set of four options.

If olfactory tests can identify conditions in people at higher risk of developing the disease early on, such as people aged 40 to 60 and over, there will be enough information to be included in clinical trials and better drugs will be developed. The researchers say studies must be conducted in the context of all risk factors for Alzheimer's, taking into account the effects of diet and exercise. Changes in smell and sense of smell should be an important part of a range of factors that affect brain health and aging. The study will further expand the range of objects, expand the data related to changes in brain structure, and further explore the relationship between changes in smell and other bodily functions.