Cain W S, Stevens J C
John B. Pierce Foundation Laboratory, New Haven, Connecticut.
Ann N Y Acad Sci. 1989;561:29-38. doi: 10.1111/j.1749-6632.1989.tb20967.x.
Most studies of how human olfaction changes with age have compared young and old. Essentially all such studies imply that aging takes a toll. The elderly have higher thresholds, perceive suprathreshold odors as being weaker, discriminate quality less well, recognize and identify common odors less well, and remember episodic presentations of odors poorly. To a first approximation, it appears that all odor qualities and functions undergo a general blunting. The few studies of persons between the young and the elderly suggest that the process of deterioration sets in early and progresses gradually. Such gradual deterioration would presumably allow the easiest accommodation to any loss and may account for why many elderly people seem oblivious to it. In some respects, ignorance may be bliss. For example, the diminished flavor of food may go unnoticed. In other respects, the loss of olfactory information may pose some nutritional and safety risks of which the elderly and perhaps even the middle-aged should be apprised. Longitudinal studies would seem to offer the only chance to decide the rate and magnitude of individual losses in olfaction. Such studies might also offer enlightenment regarding ways to forestall loss.
大多数关于人类嗅觉如何随年龄变化的研究都对年轻人和老年人进行了比较。基本上所有这类研究都表明衰老会造成损害。老年人的嗅觉阈值更高，将阈上气味感知为更淡，对气味品质的辨别能力较差，对常见气味的识别和鉴定能力较差，对气味的情景呈现的记忆也很差。初步看来，似乎所有气味品质和功能都会普遍衰退。对年轻人和老年人之间年龄段人群的少数研究表明，嗅觉衰退过程在早期就开始了，并逐渐发展。这种逐渐衰退大概会使人们最容易适应任何损失，这也许可以解释为什么许多老年人似乎对此浑然不觉。在某些方面，无知可能是福。例如，食物味道变淡可能未被注意到。在其他方面，嗅觉信息的丧失可能会带来一些营养和安全风险，老年人甚至中年人都应该对此有所了解。纵向研究似乎是确定个体嗅觉丧失速度和程度的唯一机会。这类研究也可能会为预防嗅觉丧失的方法提供启示。
