Olfactory assessment in the Chinese pediatric population

The "Sniffin' Kids-PT" test: A smell test variant for Portuguese children

OBJECTIVE

Olfactory tests tailored for children are essential, as diagnosing olfactory dysfunction at these ages can be challenging. The 16-item "Sniffin' Sticks" is reliable and easy to perform. To the best of our knowledge, there is currently no validated olfactory test for the Portuguese pediatric population. This study aimed to adapt and validate the "Sniffin' Sticks" olfactory test for the Portuguese pediatric population.

METHODS

Between August 2020 and September 2021, 354 children aged between 6 and 17years old enrolled in the study, 336 healthy children with a normal sense of smell, and 18 anosmic children with Kallmann syndrome. The study consisted of two parts. Firstly, the "Sniffin' Sticks" olfactory identification test was applied to healthy children and the odors with statistically significant low identification rates were excluded. A modified version of "Sniffin' Sticks" was defined and named "Sniffin' Kids-PT" test. Secondly, normative data were assessed and test-retest and validation tests were performed.

RESULTS

Apple and Cloves odors were identified with a low rate and were excluded from the "Sniffin' Sticks" olfactory test. In the modified 14-item "Sniffin' Kids-PT", scoring <6 (from 6-8years old), <7 (from 9-11years old) or <8 (from 12-14years old and 15-17years old) was indicative of olfactory dysfunction. The test-retest reliability was good (r=0.81; P<0.001) and the differences between scores of healthy children and anosmic children were statistically significant (U213=13.00; P<0.001).

CONCLUSION

The modified "Sniffin' Kids-PT" is a reliable test to discriminate between normosmia and olfactory dysfunction in Portuguese children over 5years old.

Odor identification impairment in autism spectrum disorder might be associated with mitochondrial dysfunction

Deficits in olfactory function in autism spectrum disorder (ASD) have already been reported. However, the results of previous studies are not consistent, and the pathophysiological mechanisms of olfactory dysfunction in ASD are not clear. Fifty-three male ASD children or teenagers aged 9-16 years were recruited for the study. The identification and discrimination portion of the Sniffin' Sticks test (SST) was used to assess the olfactory function of the enrolled subjects. The severity of ASD core symptoms and the intelligence quotient (IQ) of participants were assessed. In addition, to explore the potential mechanism underlying olfactory dysfunction, a series of plasma biochemical indicators of oxidative stress, mitochondrial function and inflammation were measured. The mean raw scores on the SST identification and discrimination test of the study subjects were significantly lower than those of typically developing subjects reported in normative data studies. After adjusting for IQ, the odor identification score was not significantly associated with any ASD symptoms. Odor identification was found to be significantly associated with the ratio of L-lactate (L)/pyruvate (P) but not with other measured indicators. The current study validates the impairment of odor identification and discrimination in Chinese ASD children. Odor identification dysfunction may be an independent clinical symptom of ASD. The plasma L/P ratio was found to be significantly associated with odor identification performance, which suggests that mitochondrial dysfunction may be a potential mechanism underlying odor identification impairment in ASD.

Effect of early olfactory training on olfactory recovery after nasal endoscopy in patients with chronic rhinosinusitis and olfactory impairment

OBJECTIVE

To analyze the effect of early comprehensive olfactory rehabilitation training on olfactory recovery after nasal endoscopy in patients with chronic rhinosinusitis and olfactory impairment.

METHODS

A retrospective study was conducted on 67 patients with chronic rhinosinusitis combined with olfactory impairment in our hospital from July 2018 to August 2020. Patients were divided into control group and observation group according to the time of implementing comprehensive olfactory rehabilitation training. The control group received non-early comprehensive olfactory rehabilitation training at 2 weeks after nasal endoscopy, and the observation group received early comprehensive olfactory rehabilitation training at 1 week after nasal endoscopy. The minimum detection/recognition threshold, olfactory threshold, olfactory function and quality of life were compared between the two groups.

RESULTS

After 3 months of training, T&T olfactory test scores in the observation group were significantly lower than those in the control group (P<0.05). The minimum detection scores in the observation group were lower than those in the control group after 1, 2 and 3 months of training, and the recognition scores in the observation group were higher than those in the control group (P<0.05). The scores of olfactory threshold, odor discrimination, and odor identification of the observation group after 1, 2 and 3 months of training were higher than those of the control group (P<0.05). After 3 months of training, the self-description scores of quality-of-life questionnaires in the observation group were higher than those in the control group, and visual analogue scale (VAS) scores in the observation group were lower than those in the control group (P<0.05).

CONCLUSION

Early comprehensive olfactory training can improve the olfactory threshold and odor discrimination of patients with chronic rhinosinusitis combined with olfactory impairment after nasal endoscopy, improve the quality of life, and have a positive effect on olfactory recovery.

Assessment of Olfactory Function in Children and Adolescents: An Overview

Valid and reliable tools for assessing olfactory function are necessary for the diagnosis of olfactory dysfunction. Olfactory testing can be challenging in a pediatric population due to shorter attention span, linguistic development, and lower olfactory experience in this age group. The aim of this article is to present an overview about olfactory tests that are suitable for a pediatric population. Publications were included when reporting new developed methods of psychophysical olfactory testing in children or adaptation and applications of existing olfactory tests for a pediatric population. Olfactory tests for all 3 major aspects of olfactory function-olfactory threshold, odor discrimination, and odor identification-were included. Olfactory tests were evaluated regarding test validity, test reliability, normative data, and test availability. The current literature shows that several tests are available to assess olfactory function in children. Especially odor identification abilities in a pediatric population are well examined and understood. Tests for olfactory threshold and odor discrimination are less frequently used. In terms of the abovementioned evaluation criteria, only a few tests met all or 3 of these 4 criteria. Based on the current literature the following tests can be recommended for valid and reliable olfactory testing in children: "U-Sniff" odor identification test, the "Sniffin' Sticks" olfactory threshold test, pBOT-6 olfactory threshold and odor identification test, NIH-Toolbox, and Smell Wheel. Age has to be considered when evaluating olfactory function in children.

Type 2 diabetes mellitus impaired nasal immunity and increased the risk of hyposmia in COVID-19 mild pneumonia patients

In patients with COVID-19, type 2 diabetes mellitus (T2DM) can impair the function of nasal-associated lymphoid tissue (NALT) and result in olfactory dysfunction. Exploring the causative alterations of T2DM within the nasal mucosa and NALT could provide insight into the pathogenic mechanisms and bridge the gap between innate immunity and adaptive immunity for virus clearance. Here, we designed a case-control study to compare the olfactory function (OF) among the groups of normal control (NC), COVID-19 mild pneumonia (MP), and MP patients with T2DM (MPT) after a 6–8 months’ recovery, in which MPT had a higher risk of hyposmia than MP and NC. No significant difference was found between the MP and NC. This elevated risk of hyposmia indicated that T2DM increased COVID-19 susceptibility in the nasal cavity with unknown causations. Therefore, we used the T2DM animal model (db/db mice) to evaluate how T2DM increased COVID-19 associated susceptibilities in the nasal mucosa and lymphoid tissues. Db/db mice demonstrated upregulated microvasculature ACE2 expression and significant alterations in lymphocytes component of NALT. Specifically, db/db mice NALT had increased immune-suppressive TCRγδ⁺ CD4⁻CD8⁻ T and decreased immune-effective CD4⁺/CD8⁺ TCRβ⁺ T cells and decreased mucosa-protective CD19⁺ B cells. These results indicated that T2DM could dampen the first-line defense of nasal immunity, and further mechanic studies of metabolic damage and NALT restoration should be one of the highest importance for COVID-19 healing.

Development of the Chinese Smell Identification Test

Smell identification ability reflects the functional integrity of the human olfactory system. Its deficit is a prodromal marker for Parkinson's disease and is also implicated in Alzheimer's disease and other neurological and psychiatric disorders. Considering the impact of cultural factors on odor identifiability, we have developed a smell identification test specifically for the Chinese population (CSIT), which includes 40 odor items that are familiar to this population, presented in a multiple-choice format. The CSIT has a test-retest reliability of 0.92 and is validated against the University of Pennsylvania Smell Identification Test (UPSIT) and the Sniffin' Sticks Identification Test 16 (SS-16). In terms of identification accuracy, Chinese participants on average score 15% higher on the CSIT than on the UPSIT or SS-16. The CSIT is also sensitive to age and gender differences in smell identification ability. As such, the CSIT provides an effective tool for the assessment of olfactory function in the Chinese population.