Unilateral reduced sense of smell is an early indicator for global olfactory loss

Abstract

It is estimated that 15% of normosmic subjects demonstrate lateralized smell loss. The majority of individuals will not notice this difference between nostrils as long as olfactory function of the better nostril remains in the normal range. We were interested in the question whether subjects demonstrating clinically significant side differences of olfactory function are at risk to develop bilateral olfactory loss. Normosmic individuals with such side differences ("difference group", n = 35) were re-tested on average 4.6 years after baseline investigations. Additionally, 58 subjects who did not demonstrate side differences ("control group") were also re-investigated. All participants received detailed olfactory testing using the "Sniffin' Sticks" involving tests for odor threshold, odor discrimination, and odor identification. Olfactory testing at follow-up indicated lower olfactory function (p = 0.005) in the "difference group" than in the "control group". The degree of side difference at baseline correlated negatively with the results from olfactory testing at follow-up (r = -0.29; p = 0.01). These results suggest that individuals with side differences of olfactory function are at risk to develop bilateral olfactory loss within 4.5 years. Thus, the degree of lateralized smell function is an indicator for future smell loss.

Influence of Binasal and Uninasal Inhalations of Essential Oil ofAbies koreanaTwigs on Electroencephalographic Activity of Human

“…The healthy elderly subjects showed larger nostril side differences in the identification of odor when compared with younger subjects. Gudziol et al [37] also suggested that the individuals with nostril side differences of olfactory function are at risk to develop bilateral olfactory loss within 4.5 years. Further, the slow yogic breathing through left nostril may alleviate stress and reduce cardiovascular disease risks compared to right nostril breathing [38].…”

Cortical and Subcortical Substrates of Cranial Nerve Function

“…Up to 15% of individuals with no complaints of decreased smell sensation demonstrate lateralized smell loss and most of them do not notice this as long as olfactory function of the better nostril remains within the normal range. 10 An injury to the secondary olfactory cortex such as the OFC results in a deficit of discrimination and recognition of odors. 11 OFC is found to have a critical role also in conscious olfactory perception.…”

Polska wersja testu Sniffin’ Sticks – adaptacja i normalizacja

“…[47][48][49]) oraz studiów klinicznych [50]. Ze względu na możliwość diagnozy różnych aspektów funkcjonowania węchu, SST może być bardzo przydatnym narzędziem zarówno dla praktyków, jak i naukowców zajmujących się węchem z bardziej teoretycznej perspektywy.…”