Subjective cognitive decline (SCD) refers to a personal experience of decreased cognitive function without objective signs of cognitive impairment from neuropsychological test performance or daily functioning abilities. SCD differs from mild cognitive impairment (MCI), such that with MCI, although daily functioning abilities are unaffected, objective cognitive impairment is identified with neuropsychological testing. SCD is very common in old people and is mostly entirely benign. As a first-year medical student, I memorised all the individual steps and molecular components of the Krebs cycle in about an hour. 40 years later, I remember that the Krebs cycle exists, but I would not attempt to learn it again. My memory is just not as good as it once was—yet I have no objective neuropsychological evidence to indicate that my cognitive test scores are lower than they should be. The same factors that contribute chronically to imperfect functioning as a physician, academic, and father continue to operate, but failing cognitive abilities do not appear to have been added to them. Given that up to 74% of people aged 70 years and older who perform normally on standard cognitive tests self-report a subjective decline in cognitive functioning, is SCD merely a feature of healthy cognitive ageing or should it be recognised as a pathological diagnosis?

中文翻译：

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主观认知下降：这有什么用？

主观认知下降（SCD）是指个人的认知功能下降经验，而没有来自神经心理学测试表现或日常功能的认知障碍的客观迹象。SCD与轻度认知障碍（MCI）不同，因此对于MCI，尽管日常功能不受影响，但通过神经心理学测试可以识别客观认知障碍。SCD在老年人中很常见，并且几乎完全是良性的。作为一年级医学生，我在大约一个小时内记住了克雷布斯循环的所有各个步骤和分子组成。40年后，我记得克雷布斯循环存在，但我不会尝试再次学习。我的记忆力不及以前，但是我没有客观的神经心理学证据表明我的认知测验分数低于应有的分数。长期导致不完善的内科医生，学者和父亲功能的相同因素继续起作用，但似乎并没有增加他们的认知能力不足。鉴于多达74％的年龄在70岁以上且在标准认知测试中表现正常的人会自我报告认知功能的主观下降，因此SCD仅仅是健康的认知衰老的特征还是应该被认为是病理诊断？但似乎没有将失败的认知能力添加到他们中。鉴于多达74％的年龄在70岁以上且在标准认知测试中表现正常的人会自我报告认知功能的主观下降，因此SCD仅仅是健康的认知衰老的特征还是应该被认为是病理诊断？但似乎没有将失败的认知能力加进去。鉴于多达74％的年龄在70岁以上且在标准认知测试中表现正常的人会自我报告认知功能的主观下降，因此SCD仅仅是健康的认知衰老的特征还是应该被认为是病理诊断？