Smell and Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Fetscherstr. 74, 01307, Dresden, Germany.
Institute of Psychology, University of Wroclaw, pl. Dawida 1, 50-527, Wrocław, Poland.
Psychol Res. 2019 Nov;83(8):1595-1611. doi: 10.1007/s00426-018-1035-2. Epub 2018 Jun 12.
Anecdotal reports suggest that blind people might develop supra-normal olfactory abilities. However, scientific evidence shows a mixed pattern of findings. Inconsistent observations are reported for both sensory-driven olfactory tasks (e.g., odor threshold) and higher-order olfactory functions (e.g., odor identification). To quantify the evidence systematically, we conducted a review and meta-analysis. Studies were included if they examined olfactory function (i.e., odor threshold, odor discrimination, free odor identification, or cued odor identification) in blind compared with a sighted control group. Articles were identified through computerized literature search. A total of 18 studies focused on olfactory threshold (n = 1227: 590 blind and 637 sighted individuals), 14 studies targeted discrimination (n = 940: 455 blind and 485 sighted), 14 studies measured cued identification (n = 968: 468 blind and 500 sighted), and 7 studies (n = 443: 224 blind and 219 sighted individuals) assessed free identification. Overall, there were no differences in effect sizes between the blind and sighted individuals after correcting the results for publication bias. We additionally conducted an exploratory analysis targeting the role played by three moderators of interests: participants' age, the proportion of women versus men in each of the studies included into meta-analysis and onset of blindness (early blind vs. late-blind). However, none of the moderators affected the observed results. To conclude, blindness seems not to affect cued/free odor identification, odor discrimination or odor thresholds.
一些传闻报告表明，盲人可能具有超常的嗅觉能力。然而，科学证据显示出混合的发现模式。在感官驱动的嗅觉任务（例如气味阈值）和更高阶的嗅觉功能（例如气味识别）中，都有不一致的观察结果报告。为了系统地量化证据，我们进行了综述和荟萃分析。如果研究比较了盲人和视力正常对照组的嗅觉功能（即气味阈值、气味辨别、自由气味识别或提示气味识别），则将其纳入研究。通过计算机文献检索识别文章。共有 18 项研究专注于嗅觉阈值（n=1227：590 名盲人，637 名视力正常者），14 项研究针对辨别力（n=940：455 名盲人，485 名视力正常者），14 项研究测量提示识别（n=968：468 名盲人，500 名视力正常者），7 项研究（n=443：224 名盲人，219 名视力正常者）评估自由识别。总体而言，在纠正出版偏倚的结果后，盲人组和视力正常组的效应大小没有差异。我们还针对三个感兴趣的调节因素的作用进行了探索性分析：参与者的年龄、每个纳入荟萃分析的研究中男女的比例以及失明的发生时间（早盲与晚盲）。然而，没有一个调节因素影响到观察到的结果。总之，失明似乎不会影响提示/自由气味识别、气味辨别或气味阈值。
