Odours, emotion and psychophysiology

Olfactory Stimulation Modulates Visual Perception Without Training

Considerable research shows that olfactory stimulations affect other modalities in high-level cognitive functions such as emotion. However, little known fact is that olfaction modulates low-level perception of other sensory modalities. Although some studies showed that olfaction had influenced on the other low-level perception, all of them required specific experiences like perceptual training. To test the possibility that olfaction modulates low-level perception without training, we conducted a series of psychophysical and neuroimaging experiments. From the results of a visual task in which participants reported the speed of moving dots, we found that participants perceived the slower motions with a lemon smell and the faster motions with a vanilla smell, without any specific training. In functional magnetic resonance imaging (fMRI) studies, brain activities in the visual cortices [V1 and human middle temporal area (hMT)] changed based on the type of olfactory stimulation. Our findings provide us with the first direct evidence that olfaction modulates low-level visual perception without training, thereby indicating that olfactory-visual effect is not an acquired behavior but an innate behavior. The present results show us with a new crossmodal effect between olfaction and vision, and bring a unique opportunity to reconsider some fundamental roles of olfactory function.

The lollipop with strawberry aroma may be promising in reduction of infusion-related nausea and vomiting during the infusion of cryopreserved peripheral blood stem cells

Nausea and vomiting during the infusion of cryopreserved peripheral blood stem cells (PBSC) are common. The aim of this study was to explore the effect of lollipop with strawberry aroma on the infusion-related nausea and vomiting of cryopreserved autologous PBSCs. We compared 2 groups of adult patients receiving lollipop with strawberry aroma during cryopreserved PBSC infusions or not to assess the incidences of nausea and vomiting occurring during infusions. All patients received granisetron 3 mg i.v. twice a day, and lorazepam 1 mg every 4 hours orally for prophylaxis of the nausea and vomiting during conditioning phase and infusion day. Before infusion, all patients were premedicated with pheniramine maleate 45.5 mg i.v. and paracetamol 500 mg orally. The patients had no evidence of nausea or vomiting prior to cryopreserved PBSC infusions. The patients with ongoing nausea or vomiting owing to conditioning regimens and/or receiving additional antiemetics were excluded from the study. One hundred fifty-eight patients who consecutively underwent autologous stem cell transplantation for malignancy were included in the study. The first 110 patients (median age: 42.5, range: 17-75) were observed for the infusion related adverse effects only. The consecutive 48 patients (median age: 48, range: 18-80) were given a lollipop with strawberry aroma during cryopreserved PBSC infusions and observed for the infusion-related adverse effects. The 2 groups were comparable with respect to age, sex, diagnosis, stem cell collection methods, conditioning regimens administered, total mononuclear cell dose infused, number of total nucleated cells (TNCs) infused, number of CD34+ cells infused, number of bags infused, total volume infused, amount of dimethylsulfoxide (DMSO), and infusion rate. Patients who received a lollipop with a strawberry aroma during infusions had significantly less nausea (6.3%, n = 3 versus 21.8%, n = 24, P = .02) and vomiting (2%, n = 1 versus 13.6%, n = 15, P = .04) than the ones who did not (observation only group). Other infusion-related adverse events were as follows; hypoxia, cough, dyspnea, abdominal cramping, tachycardia, hiccup, fever, chills, chest pain, hypotension, hypertension, agitation, sore throat, and arrhythmia. Incidences of each of these adverse events were <5% in both groups and were comparable. The use of a lollipop with a strawberry aroma during infusion of cryopreserved autologous PBSCs may be promising in reduction of infusion-related nausea and vomiting, with an easy administration at a very cheap cost.

Oncology nurses' experience of dimethyl sulfoxide odor

This article presents findings of an exploratory descriptive study on the effects of dimethyl sulfoxide (DMSO) odor in an oncology unit. The nursing staff, who had reported their concerns about the unpleasant odor emitted from patients undergoing peripheral stem cell transplantation, initiated the study. A literature review revealed some evidence of the possible ill effects on staff caring for patients having DMSO treatment, but many questions remain unanswered such as what staff experience in dealing with DMSO odor and whether nursing care is affected in any way? Data were collected through interviews with 22 oncology nurses who all had experienced direct and indirect exposure to DMSO odor. Of the 22 nurses interviewed, 20 reported that they found DMSO odor unpleasant and reported experiencing physical symptoms such as headaches and gastrointestinal reactions. The study also revealed a situation in which nurses described odor avoidance and distancing strategies that potentially compromised the nurse-patient relationship.

Emotional responses evoked by dental odors: an evaluation from autonomic parameters

Among the factors which could explain avoidance behavior toward dental care, the typical clinging odor of the dental office, due to eugenol, is investigated in this study. The hypothesis is supported by the well-known effects of odorants which may influence cognition, emotion, and behavior. The association between the odor of eugenol and dental fear and anxiety could be explained by the fact that eugenates (eugenol-containing cements) are often used in potentially painful restorative dentistry on vital teeth. The emotional impact of the odors of eugenol and two other dental products (menthol and methyl methacrylate) was evaluated on volunteer subjects through autonomic nervous system (ANS) analysis by recording the variations of six ANS parameters (two electrodermal, two thermovascular, and two cardiorespiratory) induced by the inhalation of the odorants. After the experiment, subjects were asked to fill out an 11-point hedonic scale to rate the pleasantness vs. unpleasantness for each odorant. Results were compared between two groups of subjects divided according to their own dental experience (fearful and non-fearful dental-care subjects). These showed that, in both groups, menthol was rated as pleasant and methyl methacrylate as very unpleasant, whereas eugenol was judged pleasant by non-fearful subjects but unpleasant by fearful subjects. Concerning autonomic analysis, only eugenol induced significantly different patterns of ANS responses between the two groups, with stronger variations for dentally fearful subjects, mainly observed through the electrodermal channel. These results suggest that eugenol can be responsible for different emotional states, depending on the unpleasantness of the subjects' dental experience. This seems to confirm the role of odors as elicitors of emotional memories and to support the possible influence of eugenol odor on the avoidance behavior of some subjects toward dental care.