Introduction Alzheimer's disease (AD) is a neurodegenerative disorder that affects memory, thinking, attention, and emotion or AD. Smelling problems are frequent symptoms of dementia. The aim of this study was to evaluate whether it is possible to predict if someone with anosmia or hyposmia has a higher risk of getting dementia or even AD. Methods This study was a retrospective longitudinal study, and the data used were part of a larger research project, the Vienna Conversion to Dementia Study. The 173 participants were divided into four groups based on cognitive features such as healthy control (HC), subjective cognitive decline (SCD), non-amnestic mild cognitive impairment (naMCI), and amnestic mild cognitive impairment (aMCI). Olfactory assessment and neurocognitive assessment were administered. Results We found that 30.5% of aMCI patients converted into AD after an average of about two years. The corresponding ROC analyses for olfactory testing showed that Sniffin' Sticks revealed significant results regarding the conversion to AD, whereas the Assessment of Self-Reported Olfactory Functioning and olfaction-related quality of life (ASOF) inventory using the Subjective Olfactory Capability (SOC) subscale, the Smell-Related Problems (SRP) subscale, and the Olfaction-Related Quality of life (ORQ) did not. A logistic regression showed that among the olfactory test procedures, only the Sniffin' Sticks enabled a relevant prognosis. Including neurocognitive measures in the model, only VSRT and the Trail Making Test-B. The other predictors did not contribute to the prediction of conversion to AD. Conclusion Unlike self-reporting of olfactory functioning, olfactory testing using standardized tests may have potential for predicting dementia, especially AD. However, olfactory tests have lower predictive power than neurocognitive tests such as verbal memory and divided attention tests. Implications Diagnostic tools for predicting dementia as accurately and early as possible are important. Olfactory assessment, compared to neurocognitive tests for verbal memory and divided attention, is inferior in predicting the prognosis of AD.
Odor perception can be achieved through ortho or retronasal routes, with the latter being an important component of flavor perception. There are significant olfactory differences that exist between rats and humans and by understanding the role of structural differences, further insight can be gained into the mechanism of odorant perception via ortho or retronasal routes. 3D human and rat (Sprague–Dawley) computational models were used to investigate nasal anatomy impact on ortho vs. retronasal odorant transport to the olfactory epithelium. The nasal pharynx region was modified for human and rat models to probe nasal structure impact on ortho vs. retro olfaction. Sixty-five odorant absorption rates to the olfactory epithelium were extracted from each model. The retronasal route provided higher peak odorant absorption compared to orthonasal route for human (left: 90
Odor imagery is known to be more difficult than any other modality of sensory imagery. Consequently, wide between-individuals variability can be found in odor imagery ability. Several studies have shown a positive relationship between olfactory performance and odor imagery ability. In the light of factors known to influence smelling ability, this study therefore investigated the effects of two factors — gender and age — known to influence smelling ability, on self-declared odor imagery ability in normosmic individuals. Seven hundred and nine French participants were asked to complete the web version of the French Vividness of Olfactory Imagery Questionnaire (fVOIQ). General linear models were used to determine the contributions of gender and age to odor imagery vividness scores. Moreover, scores were compared between age intervals ranging from 18–30 years old to 60 + years old. Our findings reveal that at any age, men and women have the same odor imagery ability. Odor imagery ability in self-declared normosmic individuals improves with age until 50–60 years old, and beyond this point the often-reported age-related olfactory decay does not alter it. These findings suggest a high contribution of daily olfactory experience to the development of this cognitive function, and a relationship with olfactory performance that appears less linear than hypothesized. This study provides food for thought in the field of olfaction: it suggests that distinct mechanisms may underlie two cognitive processes, perception and sensory imagery.
The effect of seven virtual environments (visual and auditory) on the rating of sensory attributes of identical samples of ketchup and salad dressing was assessed. Fifty-one participants were recruited and immersed in virtual scenes evoking heat, cold, height and fear, high speed and fear, sadness, pleasure, and relaxation. The participants tasted samples of both products while being subjected to virtual stimuli. Each panelist tested the seven environments, and control tests were carried out without the VR headset. Panelists rated eight descriptive attributes based on their perception, and results were analyzed by principal component analysis to obtain a general overview of the rated attributes, and by generalized procrustes to explain possible correlations between virtual environments and attribute ratings. Heat evoking scene caused increased intensity of hotness and moisture, and decreased bitterness; cold evoking scene increased sweetness perception. Virtual environments increased sweetness, moisture, and bitterness perception in men when compared to women. Virtual reality contexts influenced the taste and texture perception of ketchup and salad dressing; moreover, the effect of these stimuli was different in men and women. Besides applications in condiments, the obtained results can shed light on the influence of virtual stimuli on food product sensory perception in general, since virtual environments for sensory tests are gaining great interest for researchers and the food industry.
Introduction The human sense of smell has different functions which can be categorized as “food,” “social,” and “environment.” Different questionnaires about the importance of olfaction in adults are available, but little attention has been paid to children and adolescents. Therefore, we aimed to develop a questionnaire about children’s personal significance of olfaction (ChiPSO). Methods The questionnaire was developed in two steps. The first questionnaire included 33 statements about the importance of olfactory information in daily life — covering three subscales “food,” “environment,” and “social” administered to 191 participants (mean age: 14.4 ± 1.7 years). The five best fitting items of each subscale were chosen for the final 15-item questionnaire. In the second part, we administered the developed questionnaire to 208 children and adolescents (mean age: 11.5 ± 3.5 years) who additionally underwent olfactory testing to investigate the association between olfactory function and questionnaire results. Participants were separated in two age groups: (i) 6–11 years (children), (ii) 12–17 years (adolescents). Results A significant influence of age on the total ChiPSO score and all three subscales with adolescents scoring higher than children was found. Additionally, there was a significant influence of sex in adolescents on total ChiPSO score and subscales “social” and “food” with girls scoring higher than boys. Conclusion We report an association between questionnaires results and olfactory performance. Additionally, olfactory information seems to be more important to adolescents compared to children and girls compared to boys. Implications The ChiPSO questionnaire is a practical tool to evaluate the importance of olfactory information in children and adolescents aged 6–17 years.
