Pellegrino Robert, Han Pengfei, Reither Nicole, Hummel Thomas
Smell and Taste Clinic, Department of Otorhinolaryngology, Dresden University of Technology, Dresden, Germany.
Department of Food Science, Institute of Agriculture, University of Tennessee, Knoxville, Tennessee, U.S.A.
Laryngoscope. 2019 Aug;129(8):1737-1743. doi: 10.1002/lary.27832. Epub 2019 Mar 8.
OBJECTIVE/HYPOTHESIS: A common, lasting condition from traumatic brain injury is impairment to smell. In patients with olfactory impairment, recent meta-analyses have demonstrated that olfactory training consistently improves higher-order functions, such as odor identification. The focus of this work was to assess effects of olfactory training (OT) in posttraumatic olfactory loss patients through several metrics including psychophysical, olfactory bulb (OB) volume, and functional magnetic resonance imaging.
Prospective cohort study.
Sniffin' Sticks were used to classify two patient groups (anosmic [N = 23] and hyposmic [N = 14]) and measure changes after OT. Additionally patients were asked the intensity, valence, and uncued identification of odors presented (coffee and peach) within the magnetic resonance imaging scanner before and after olfactory training. Olfactory training was performed twice daily with a four-odor training set for 24 weeks, and sets were replaced halfway through the entire training session (~12 weeks).
Patients had an increase in test scores (threshold and identification) and in-scanner intensity ratings and identification. Anosmic patients showed improved olfactory thresholds to 2-phenylethanol, increased intensity ratings, and activation in the right superior frontal gyrus (SFG) to odors after OT. Hyposmic patients were able to identify odors better after training. This behavior was mirrored with increased, ipsilateral activations in semantic processing areas such as Broca's area, left angular gyrus, and left SFG.
Taken together, along with neither patient group showing changes in OB volumes, OT improves olfactory performance in patients with posttraumatic olfactory loss and seems to be driven, at least in part, by top-down processes (central) rather than bottom-up (peripheral).
2 Laryngoscope, 129:1737-1743, 2019.
目的/假设：创伤性脑损伤后常见的持久性病症是嗅觉障碍。在嗅觉障碍患者中，近期的荟萃分析表明，嗅觉训练能持续改善诸如气味识别等高级功能。本研究的重点是通过包括心理物理学、嗅球（OB）体积和功能磁共振成像在内的多项指标，评估嗅觉训练（OT）对创伤后嗅觉丧失患者的影响。
前瞻性队列研究。
使用嗅棒对两组患者（嗅觉丧失组[N = 23]和嗅觉减退组[N = 14]）进行分类，并测量嗅觉训练后的变化。此外，在嗅觉训练前后，要求患者在磁共振成像扫描仪内对呈现的气味（咖啡和桃子）的强度、效价和非提示性识别进行评价。嗅觉训练每天进行两次，使用四种气味的训练集，持续24周，在整个训练过程的中途（约12周）更换训练集。
患者的测试分数（阈值和识别）、扫描仪内强度评分和识别能力均有所提高。嗅觉丧失患者在嗅觉训练后，对2-苯乙醇的嗅觉阈值有所改善，强度评分增加，右侧额上回（SFG）对气味的激活增强。嗅觉减退患者在训练后能够更好地识别气味。这种行为与语义处理区域（如布洛卡区、左侧角回和左侧SFG）同侧激活增加相对应。
综上所述，两组患者的嗅球体积均未显示变化，嗅觉训练可改善创伤后嗅觉丧失患者的嗅觉表现，且似乎至少部分是由自上而下的过程（中枢）而非自下而上的过程（外周）驱动的。
2《喉镜》，129:1737 - 1743，2019年。
