Can Sodium Citrate Effectively Improve Olfactory Function in Non-Conductive Olfactory Dysfunction? / 대한이비인후과학회지

The objective of this study was to perform a systematic review of the literature for application of intranasal sodium citrate in the patients with olfactory dysfunction to help determine the sodium citrate treatments for this condition. Two authors independently searched the data base (Medline, Scopus, and the Cochrane database) for relevant studies from inception to January 2018. Included studies were randomized controlled studies published in English comparing topical sodium citrate application (treatment group) with saline (control group) in patients who had olfactory dysfunction. Outcomes of interest included the change of olfactory identification and threshold during 2 hours post-treatment. Three studies were enrolled in the meta-analysis. Compared with control group, treatment group did not increase posttreatment score of olfactory identification [standardized mean difference (SMD)=-0.03; 95% confidence interval (CI)=-0.29-0.24; I²=0%] and olfactory threshold (SMD=0.18; 95% CI=-0.09-0.45; I²=0%) significantly. In the degree of pre-post improvement of two outcomes, although treatment group statistically showed the significant improvement in olfactory threshold (SMD=0.30; 95% CI=0.05-0.55; I²=17%), the clinical significance of this outcome was meaningless. Similarly, there was no significant difference in olfactory identification between two groups (SMD=0.17; 95% CI=-0.11-0.45; I²=22%). Unlike the recent favorable results, our summated results presented the uselessness for the local application of sodium citrate in improving patient's olfactory function. However, we also had some limitation such as small sample size and inconsistent application methods. Therefore, larger trials and standardized methodology are needed to reach more stronger and exact results.

Assessing Olfactory Function in Healthy Korean Children Using the Cross-Cultural Smell Identification Test and Butanol Threshold Test / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: There are no reported studies of olfactory function of Korean children, and the existing tests of olfactory function for Korean adults may not be suitable for very young children. This study assessed the applicability of the Butanol Threshold Test (BTT) and Cross-Cultural Smell Identification Test (CC-SIT) to children. SUBJECTS AND METHOD: A total of 79 children were included in the study: they were between 6-12 years of age, and had visited University Hospital Health Care Center between January 2012 and December 2013. All children were administered the BTT and CC-SIT. RESULTS: Using BTT, 69.62% of the sample was classified as moderate hyposmia. On the other hand, when CC-SIT was used, 45.57% of the sample was classified as moderate and 43.04% as mild hyposmia. CC-SIT and BTT scores were not correlated. Although gender and age were not taken into account in the test results, the CC-SIT could measure age-specific olfactory development. CONCLUSION: Our study provides fundamental data on the clinical use of the CC-SIT and BTT in healthy Korean children.

The Changes of Olfactory and Trigeminal Pungency Thresholds in n-Aliphatic Alcohols with Different Carbon Chain in Normal Adults / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Using n-aliphatic alcohols whose physical properties change gradually as their length increases, we investigated the changes of olfactory threshold and trigeminal pungency threshold with the increase of carbon chain length. MATERIALS AND METHOD: Olfactory and trigeminal pungency thresholds were measured in ethanol (C2), 1-butanol (C4), 1-hexanol (C6) and 1-octanol (C8) in 40 normal adults using a two-alternative forced-choice modified by the ascending method of limit (CCCRC) test. Plastic bottles with 30 ml of four n-aliphatic alcohols were diluted threefold successively by mineral oil. Plastic bottles containing only mineral oil were used as controls. RESULTS: The olfactory and trigeminal pungency thresholds decreased and the ratio of olfactory threshold/trigeminal pungency threshold increased with the length of carbon chain in n-aliphatic alcohols. The correlation coefficients among olfactory thresholds in each alcohol were higher than those among trigeminal pungency thresholds. CONCLUSION: Alcohol with long carbon chains showed low olfactory and trigeminal pungency thresholds, indicating that high lipid solubility is an important factor in olfaction and trigeminal chemosensitivity.

Measurement of Nasal Trigeminal Pungency Threshold: Comparison between Normals and Patients with Decreased Sense of Smell

BACKGROUND AND OBJECTIVES: In order to measure the level of nasal trigeminal pungency threshold and to evaluate the interaction between olfactory and trigeminal nerves, we measured olfactory thresholds and trigeminal pungency thresholds using 1-butanol in 40 normal people and in 46 patients with decreased sense of smell by non-sinonasal origin. MATERIALS AND METHODS: Two-alternative forced-choice modified ascending method of limit (CCCRC test) was used for the measurement of olfactory and pungency thresholds, using 1-butanol plastic squeezable bottles successively threefold diluted by distilled water as stimulus, while distilled water as blank. RESULTS: There was a statistically significant difference in pungency threshold between normals (2.18+/-1.5 dilution step) and patients (1.11+/-1.0 dilution step)(p<0.001). CONCLUSION: The pungency thresholds of hyposmics and anosmics are higher than those of normals, which suggests that a loss or decrease of olfactory sensation is accompanied by a simultaneous decrease of trigeminal chemosensitivity.

Comparison of Olfactory Threshold Tests:CCCRC Test versus Step Method / 대한이비인후과학회지

There are many variables that can be manipulated in the study of olfactory thresholds. They include the choice of odorant, the way to bring the stimulus to the subject's nose, number of trials, interval between trials, dilution method, environmental conditions, as well as psychophysical method. The focus of this study lay on how much differences were made by the psychophysical method, the sequence of presentations of stimuli that led to calculation of an index of sensitivity and how reliable the result of step method in olfactory threshold testing is. The olfactory threshold tests entailed comparison of procedures: 1) a procedure of two-alternative forced-choice(2AFC) testing by an ascending method of limits(CCCRC test), 2) a two-alternative forced-choice(2AFC) version of step method that used a computerized algorithm to calculate threshold on an ongoing basis throughout testing. As a result, mean concentration difference of 7.6-fold was achieved in the thresholds by the two procedures and inter-test correlation coefficient was 0.46. Estimation of threshold in the step method remained relatively constant after 10 trials to the end of the 30 test-trials without biases, which meant step method showed coherent data. Accordingly step method is suitable for olfactory threshold test despite of relatively long testing time.

Measurement of Olfactory Threshold in Normal Korean Adults with Combined Use of Bounded CCCRC Test and Step Method

The high variability of measured olfactory thresholds in humans reflects very broad range of sensitivity within and among individuals. This can be derived from the strongly compressive nature of olfaction, which makes it relatively hard to compare the size of two stimuli in odor sensation. However, we know that some portion of the variation is the result of extrinsic factors e.g. the method used to measure the olfactory threshold. For this reason, in order to address the bias and reliability of a psycophysical method, we combined the use of the CCCRC (Connecticut Chemosensory Clinical Research Center) test with the step method in 40 normal Korean adults twice a week for the evaluation of threshold. The measured thresholds showed high test-retest reliability and the threshold estimates remained consistent during the testing without trial-biases. Based on the results, we can conclude that a combined test using the CCCRC test and step method can be used in the measurement of olfactory threshold in a clinical context.