Olfactory training in 8-year-olds increases odour identification ability: a preliminary study.

Olfactory training (OT), smelling odours, twice per day for an extended period, can improve the olfactory function in adults. The aim of the current study was to investigate whether OT can improve the olfactory function of children aged 8 years old. Odour thresholds and odour identification ability were compared between two groups across three separate testing sessions (baseline, 6-week post-baseline, 12-week post-baseline). After the baseline test, the control group (n = 21) completed 6 weeks of bi-daily OT with odourless stimuli, whereas the experiment group (n = 20) completed 6 weeks of bi-daily OT, smelling four different odours (eucalyptus, lemon, clove, rose). A repeated measure analysis of variance was used to test for group differences across the three testing sessions. Six weeks after OT had been completed, participants in the experiment group demonstrated a significant increase in odour identification scores (9.95 to 11.20), compared to the control group who demonstrated no increase (10.48 to 10.48). No group differences in odour threshold ability were found.Conclusion: Six weeks of OT enhances odour identification ability, but not odour thresholds, in 8-year-old children. What is Known: • Smell loss and dysfunction are associated with negative health outcomes such as depression and increased risk of consuming contaminated food. • Olfactory training can improve sense of smell in adults. What is New: • Olfactory training improves odour identification ability in 8-year-olds. • Olfactory training does not appear to enhance odour acuity in 8-year-olds.

Etiologies of olfactory dysfunction in a pediatric population: based on a retrospective analysis of data from an outpatient clinic.

PURPOSE: Although the prevalence of olfactory dysfunction in children is thought to be lower compared to adults, little is known about the actual frequency of etiologies of smell dysfunction in children. Aim of the study was (i) to describe the epidemiology of olfactory dysfunction in a pediatric population and (ii) to compare the distribution of etiologies to adults. MATERIAL AND METHODS: Data of patients consulting a smell and taste clinic between 2000 and 2017 were retrospectively analyzed. Frequency of major causes of olfactory dysfunction was examined with a focus on the pediatric population. RESULTS: A total of 7153 patients (164 children) were included in the analysis. Most children presented with congenital olfactory dysfunction (67%), or head-trauma (12%). In contrast, the cumulative frequency of olfactory loss associated with sinonasal disorders or acute infections of the upper airways was 6%. The frequency of etiologies of olfactory dysfunction changed with age: While the frequency of patients with congenital anosmia decreased, the frequency of causes related to infections of the upper respiratory tract and idiopathic causes increased. CONCLUSION: About 2/3 of olfactory dysfunction in children are congenital while 1/3 is acquired. The frequency of etiologies causing olfactory dysfunction change significantly from children to an adult population.

A computer-controlled olfactometer for a self-administered odor identification test.

Odor identification tests are widely used for the general screening of olfactory function. However, the administration of odor identification tests is often limited due to a lack of investigators' time. Therefore, we attempted to design a computer-controlled olfactometer to present a self-administered odor identification test. The results produced by means of this olfactometer were evaluated in terms of validity and test-retest reliability. To test the validity, participants' performance in the odor identification test using the olfactometer was compared with their performance in the odor identification test using the validated assessment of the "Sniffin' Sticks" test. The ten-item odor identification test was performed two times using two different methods: (1) the self-administered test using the computer-controlled olfactometer and (2) the foreign-administered test using the "Sniffin' sticks." To examine test-retest reliability, 20 participants were asked to repeat these tests on a different day. Participants reached significantly higher scores on a foreign-administered odor identification test using the "Sniffin' sticks" than on the olfactometer-based test; however, this effect was driven by two less correctly identified odors in the olfactometer-based test. The significant difference between both methods in the mean scores disappeared after excluding two odors from the analysis. In addition, both methods showed no significant difference in scores obtained during the first and second session, indicating that results were consistent between sessions. In conclusion, our findings demonstrate that the computer-controlled olfactometer designed in this study can be used for a self-administered odor identification test.

Time frequency analysis of olfactory induced EEG-power change.

OBJECTIVES: The objective of the present study was to investigate the usefulness of time-frequency analysis (TFA) of olfactory-induced EEG change with a low-cost, portable olfactometer in the clinical investigation of smell function. MATERIALS & METHODS: A total of 78 volunteers participated. The study was composed of three parts where olfactory stimuli were presented using a custom-built olfactometer. Part I was designed to optimize the stimulus as well as the recording conditions. In part II EEG-power changes after olfactory/trigeminal stimulation were compared between healthy participants and patients with olfactory impairment. In Part III the test-retest reliability of the method was evaluated in healthy subjects. RESULTS: Part I indicated that the most effective paradigm for stimulus presentation was cued stimulus, with an interstimulus interval of 18-20s at a stimulus duration of 1000ms with each stimulus quality presented 60 times in blocks of 20 stimuli each. In Part II we found that central processing of olfactory stimuli analyzed by TFA differed significantly between healthy controls and patients even when controlling for age. It was possible to reliably distinguish patients with olfactory impairment from healthy individuals at a high degree of accuracy (healthy controls vs anosmic patients: sensitivity 75%; specificity 89%). In addition we could show a good test-retest reliability of TFA of chemosensory induced EEG-power changes in Part III. CONCLUSIONS: Central processing of olfactory stimuli analyzed by TFA reliably distinguishes patients with olfactory impairment from healthy individuals at a high degree of accuracy. Importantly this can be achieved with a simple olfactometer.