Olfactory Nomenclature: An Orchestrated Effort to Clarify Terms and Definitions of Dysosmia, Anosmia, Hyposmia, Normosmia, Hyperosmia, Olfactory Intolerance, Parosmia, and Phantosmia/Olfactory Hallucination

BACKGROUND

Definitions are essential for effective communication and discourse, particularly in science. They allow the shared understanding of a thought or idea, generalization of knowledge, and comparison across scientific investigation. The current terms describing olfactory dysfunction are vague and overlapping.

SUMMARY

As a group of clinical olfactory researchers, we propose the standardization of the terms "dysosmia," "anosmia," "hyposmia," "normosmia," "hyperosmia," "olfactory intolerance," "parosmia," and "phantosmia" (or "olfactory hallucination") in olfaction-related communication, with specific definitions in this text.

KEY MESSAGES

The words included in this paper were determined as those which are most frequently used in the context of olfactory function and dysfunction, in both clinical and research settings. Despite widespread use in publications, however, there still exists some disagreement in the literature regarding the definitions of terms related to olfaction. Multiple overlapping and imprecise terms that are currently in use are confusing and hinder clarity and universal understanding of these concepts. There is a pressing need to have a unified agreement on the definitions of these olfactory terms by researchers working in the field of chemosensory sciences. With the increased interest in olfaction, precise use of these terms will improve the ability to integrate and advance knowledge in this field.

Assessment of Olfaction Following Endoscopic Sinus Surgery

To assess the olfactory outcomes following Endoscopic Sinus Surgery (ESS) in patients diagnosed with Chronic Rhinosinusitis (CRS) and Sinonasal polyposis (SNP). To assess and compare the pre-operative and post-operative olfactory scores of patients undergoing ESS/ ESS + polypectomy/ESS + Septoplasty by subjective and objective methods. This is a prospective, cohort study which included a total of 60 patients. Subjective assessment was done using a Questionnaire. Preoperative olfactory assessment was performed with Sniffing Sticks. Olfactory assessment was done at 1st,3rd, 6th and 12th week following surgery. The preoperative and postoperative scores were statistically analysed and compared. In patients who underwent ESS, there was a significant reduction in olfactory scores in the immediate few weeks after surgery which improved over time by the end of 3 months. In patients who underwent ESS with polypectomy, there was a significant improvement in olfactory scores from the third week following surgery which was sustained over 3rd month follow-up. In patients who underwent ESS with Septoplasy, there was a significant decrease in olfactory scores during the initial few weeks with a marginal improvement during 3 months follow-up. At the end of 12 weeks post ESS, no patient was found to be anosmic. Patients with pre-existing hyposmia did not show statistically significant change post surgery.However patients with anosmia showed statistically significant improvement in olfactory function, but did not become normosmic at 12th post-operative week. Majority of normosmics did not have alteration in their olfactory perception at 12th post-operative week.

Biallelic PROKR2 variants and congenital hypogonadotropic hypogonadism: a case report and a literature review

Congenital hypogonadotropic hypogonadism (CHH) is a rare disorder that causes gonadotropin-releasing hormone (GnRH) deficiency and sexual immaturity. CHH may accompany an abnormal sense of smell (Kallmann syndrome, KS) or no such manifestation (normosmic-CHH). This unusual combination of manifestations is explained by the fact that GnRH neurons originate in the olfactory placode and migrate to the forebrain during embryogenesis. We describe the case of a 31-year-old man with normosmic-CHH, who also had obesity, type 2 diabetes and intellectual disability. He was noticed to have sexual immaturity (small testes with no pubic hair) at age 20 years, when diabetic ketoacidosis developed. Basal and GnRH-stimulated levels of LH (1.0→12.0 IU/L) and FSH (1.9→6.1 IU/L) were detectable but low. The results of the T&T olfactometer and the Alinamin test were definitely normal, with an anatomically normal olfactory system on MRI. Sequencing of 22 CHH-related genes was performed, and compound heterozygous PROKR2 variants were identified: one was a previously known loss-of-function variant (p.Trp178Ser) and the other was a nonsense variant (p.Trp212*). Through a literature review, we found 22 patients (including our patient) with CHH due to biallelic PROKR2 variants, which led us to recognize that most of the patients (86%) were diagnosed with KS. Clinical observations in this study indicate that, even though they have CHH, biallelic PROKR2 variant carriers may have a normal olfactory system as well as presumably normal migration of GnRH neurons. This suggests that the PROK2-PROKR2 pathway affects the function of GnRH neurons after their migration.

Fast Screening of Olfactory Function Using the Q-Sticks Test

OBJECTIVES

Classical, longer olfactory tests are associated with difficulties in everyday practice. The aim of this study was to investigate the clinical utility of the Q-Sticks test within the context of a multicenter study.

METHODS

A total of 333 subjects, aged between 12 and 88 years, completed a 3-item Q-Sticks test and a longer Sniffin' Sticks identification test. We analyzed the sensitivity and specificity of the test results for different cutoffs for anosmia and hyposmia.

RESULTS

Our study showed that the test can be used on subjects aged 12 years and older, regardless of their sex. The data indicated a test sensitivity and specificity of 91.8 and 92%, respectively, with a score of 2 taken as a cutoff for olfactory dysfunction. Conversely, normal olfactory function can be declared with high probability with a score of 3 in the Q-Sticks test.

CONCLUSION

We reconfirmed that the Q-Sticks test is a good screening tool for everyday medical practice and in laboratory settings, although it has to be kept in mind that the test can produce false-negative results at a score of 3. The test was relatively sensitive to anosmia and differences between normosmic and hyposmic/anosmic patients.

Whose nose does not know? Demographical characterization of people unaware of anosmia

PURPOSE

For functionally anosmic subjects, the sense of smell is basically useless in daily activities-they are unlikely to detect the threatening smell of rotten food, gas or smoke, or to enjoy the flavor of food or the smell of perfumes. Although this appears very distressing, functionally anosmic subjects in our sample seemed not to be aware or bothered with impaired olfaction and enrolled for the study targeted to people with a normal sense of smell.

METHODS

In the large sample of 9139 subjects who declared themselves to have a normal sense of smell, we have retrospectively found a notable proportion of scores indicating functional anosmia.

RESULTS

When we look at the overall Sniffin' Sticks score, 0.45% of the sample was functionally anosmic and this fraction increased to 3.4% when the identification score of 8 points and below was used. We present demographical information of those subjects, who despite their inability to use smell in daily life, consider themselves healthy.

CONCLUSIONS

Data offer a new perspective on the importance of olfaction in daily life and supports the notion about the importance of using screening tools in clinical practice.