Reproductive endocrine influences upon olfactory perception: A current perspective

Olfactory Fluctuation Revisited

OBJECTIVES

Many patients complain about olfactory fluctuation (OF), which is a symptom commonly attributed to sinonasal disease. Data-based evidence for its association with sinonasal disease is scarce. The aim of the study is to identify explanatory variables associated with OF and to analyze its predictive value regarding sinonasal disease.

STUDY DESIGN

We performed a retrospective study based on patients with olfactory dysfunction.

METHODS

We analyzed data from 482 patients attending the smell and taste outpatient clinic with full psychophysical workup and structured questions regarding their symptoms. The questionnaire included items on OF and chronic nasal symptoms. Clinical investigators filled out the second part of this questionnaire that included information about nasal endoscopy, psychophysical tests of orthonasal olfaction (Sniffin' Sticks), retronasal olfaction, and putative etiology of olfactory dysfunction.

RESULTS

OF was more prevalent in sinonasal disease (42.4%) compared to other putative etiologies of olfactory dysfunction such as postinfectious (28%) or posttraumatic (11.7%) (X2 [5, n = 440] = 24.98; P < .0001). OF was strongly associated with Sniffin' Sticks score categories (anosmia, hyposmia, normosmia) (X2 [2, n = 424] = 39.21; P < .0001; Cramer's V = 0.30; P < .0001) and presence of "chronic nasal symptoms" (X2 [1, n = 437] = 22.71; P < .0001; Cramer's V = 0.23; P < .0001). The accuracy in predicting putative sinonasal disease etiology when OF was present depended strongly on the clinical context.

CONCLUSION

Olfactory fluctuation is a symptom mostly but not exclusively associated with sinonasal disease, elevated Sniffin' Sticks test scores, and is frequently accompanied by other nasal complaints. Its presence is valuable information for clinicians to be integrated into the clinical context when doing patients' workup.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:2442-2447, 2020.

Human awareness and uses of odor cues in everyday life: Results from a questionnaire study in children

The Children's Olfactory Behavior in Everyday Life questionnaire was developed to assess attention to, and uses of, odors in real-life situations, and to evaluate individual variations. The tool comprises 16 items prompting self-reports of active seeking, awareness and affective reactivity to odors of food, people and the environment. Children (102 girls, 113 boys) aged 6–10 years participated in the study. The results revealed that girls were significantly more olfaction-oriented than boys, especially towards the odors of people, self and the environment. An increasing ability of children to describe the odor facets of their perceptual world was found between 6 and 10 years, partly due to ameliorating verbal skills. Finally, owning an “attachment object” was linked to olfactory reactivity to odors, especially in social and affective contexts. Overall, this research contributes to expand our understanding of the behavioral importance of odors in children and its individual variations, and it brings additional arguments against the prevalent concept of functional microsmaty applied to the human species.

Thresholds and chemosensory event-related potentials to malodors before, during, and after puberty: differences related to sex and age

A sex-related difference in olfactory sensitivity to androstadienone and androstenone has been reported to occur during puberty. The study reported here extends this work to investigate whether sex and age differences exist before, during, and after puberty for 2-methyl, 3-mercapto-butanol (2M3M; a malodorous component of human sweat), carbon disulfide/hydrogen sulfide (H2S), and androstadienone. A total of 121 participants took part in the study (58 females, 63 males; age range 9-20 years). Participants were divided into 3 groups (i) pre-puberty, (ii) puberty and (iii) post-puberty. Threshold measurements for (i) androstadienone, (ii) 2M3M and (iii) carbon disulfide were recorded. Chemosensory event-related potentials (CSERPs) were recorded using air-dilution olfactometry. The results revealed that female thresholds for the three odorants were stable between the three age groups. Pubescent males had higher thresholds (less sensitive) for all three odorants. In the post-puberty group, sex differences were only observed for 2M3M. These differences are mirrored by significant sex differences for CSERP latencies. The latency increase in male pubescents may be due to the production of sweat by the apocrine glands resulting in increased levels of 2M3M and androstadienone, resulting in adaptation. To conclude, based on the present study performed in a relatively large sample, the processing of malodors in males is different from that of females during puberty. This observation not only relates to a reduced sensitivity towards odors typially found in axillary sweat but also extends towards other malodors. While the underlying cause may be partly due to specific adaptation towards malodors present in axillary sweat it might also reflect hormonal changes modifying the perception of odors.

Changes in sensitivity to the odor of androstenone during adolescence

While it has been reported that most, if not all, very young children are able to detect the odor of 5 alpha-androst-16-en-3-one (androstenone), approximately 40-50% of human adults cannot detect its odor. The present study focused on changes in sensitivity to androstenone during adolescence, which may account for this discrepancy. Sensitivity to androstenone was determined in 247 subjects aged 6 to 50. There was a significant increase in the number of males anosmic to androstenone between 9-14 and 15-20 years of age, and a significant increase in threshold with age among males able to detect the odor. We infer that a smaller percentage of females than males becomes anosmic to the odor of androstenone during development, and those able to detect it apparently show a decrease in threshold with age. No age-related changes were observed in tests of pyridine or d,l-beta-phenylethylmethylethylcarbinol (PEMEC).