Relationships between autistic traits, taste preference, taste perception, and eating behaviour.

Individuals with autism spectrum disorder exhibit atypical taste perception and eating behaviours. However, little is known about the effect of autistic traits on eating behaviours in the general population. This study explored the relationships between autistic traits, taste preferences, taste perceptions, and eating behaviours among Japanese population using an online questionnaire survey. The results showed significant effect of autistic traits on eating behaviours, that people with higher autistic traits tended to have higher selective eating behaviours, such as increased sensitivity to food texture and mixed flavours. Moreover, selective eating behaviours were correlated with the preference for sour taste and aftertaste sensitivity. Those results suggest that eating behaviours can be influenced by the relationship between autistic traits, taste perceptions, and taste preferences. We discuss these results in the context of previous findings, and future investigations into the possibility of solving selective eating problems in individuals with autism.

Trial measurement of brain activity underlying olfactory-gustatory synchrony perception using event-related potentials from five female participants.

Temporal synchrony between odor and taste plays an important role in flavor perception. When we investigate temporal synchrony between odor and taste, it is necessary to pay attention not only to physical simultaneity of the presentation of olfactory and gustatory stimuli, but also to the perceptual simultaneity between the two stimuli. In this study, we examined short-latency brain activity underlying synchrony perception for olfactory-gustatory combinations. While five female participants performed a simultaneity judgment (SJ) task using soy sauce odor and salt solution, single-channel event-related potentials (ERPs) were recorded at the position of Cz. In each trial, the participant was asked whether olfactory and gustatory stimuli were perceived simultaneously or successively. Based on the judgment responses acquired from participants (i.e., simultaneous or successive), ERP data were classified into two datasets. The means of ERPs from each participant were calculated for each type of judgment response, considering the onset of olfactory or gustatory stimuli (OERPs or GERPs, respectively) as the starting point. The latencies of the P1 component of GERPs were very similar between simultaneous and successive judgment responses, whereas the P1 amplitudes differed significantly. These results indicated that neural activity affecting SJ for an olfactory-gustatory combination is generated during a period of about 130 ms from the onset of gustatory stimulus. Thus, olfactory and gustatory information processing related to flavor perception (more specially, synchrony perception between odor and taste) might be initiated at a relatively early stage of the central pathway.

Superiority of experts over novices in trueness and precision of concentration estimation of sodium chloride solutions.

Several studies have reported that experts outperform novices in specific domains. However, the superiority of experts in accuracy, taking both trueness and precision into consideration, has not yet been explored. Here, we examined differences between expert and novice performances by evaluating the accuracy of their estimations of physical concentrations of sodium chloride in solutions while employing a visual analog scale. In Experiment 1, 14 experts and 13 novices tasted 6 concentrations of the solutions until they had learned their intensities. Subsequently, they repeatedly rated the concentration of 3 other solutions in random order. Although we did not find a difference between the performances of the 2 groups in trueness (difference between rating and correct concentration), the precision (consistency of ratings for each participant) of experts was higher than that of novices. In Experiment 2, 13 experts who had participated in Experiment 1 and 10 experts and 12 novices who had not participated in Experiment 1 rated the salt concentration in sodium chloride/sucrose mixtures in the same way as in Experiment 1. Both trueness and precision of performance were higher in both expert groups than in the novice group. By introducing precision and trueness parameters, we succeeded in quantifying the estimations of experts and novices in rating the concentration of solutions, revealing experts' superiority even for a task they had not been trained for.

Olfactory-gustatory simultaneity judgments: A preliminary study on the congruency-dependent temporal window of multisensory binding.

BACKGROUND: A greater congruency of audio and video expands the temporal binding window (TBW). A similar phenomenon may occur with a combination of odor and taste, which are the main components of flavor. OBJECTIVE: TBW is defined as the temporal resolution of synchrony perception. The larger the TBW, the lower the resolution. We hypothesized that the more congruent the odor and taste, the lower the temporal resolution of synchrony perception. METHODS: To examine this hypothesis, 10 female participants performed simultaneity judgment (SJ) tasks under congruent (soy sauce odor with saline) and incongruent (cherry tree leaf odor with saline) conditions and evaluated the congruency with saltiness for the two odors. In the SJ tasks, participants reported whether odor and taste were presented simultaneously or successively. We assumed a Gaussian distribution for the temporal distributions of the simultaneous response rates and calculated the approximations. In addition, we computed the half width at half height (HWHH) as an index of TBW based on the coefficient of approximation for the temporal distribution of the simultaneous response rates. RESULTS: HWHH was significantly larger under congruent condition than under incongruent condition. In addition, congruency with saltiness had a significant moderate positive correlation with HWHH. CONCLUSION: The larger the HWHH, the lower the temporal resolution of synchrony perception, supporting the hypothesis. This study suggests that the width of TBW depends on the cross-modal congruency similar to the case for audio-visual SJs. However, methodological improvements, including a larger sample size and gender-independent recruitment of participants, are essential to enhance the reliability of the findings because some of the results did not provide sufficient ESs or power.

Change in preference for vegetables and their perceptual attributes as a function of age and pickiness.

Preference for vegetables is influenced by various factors, including demographic, psychological, socio-environmental, and genetic factors. This study confirmed that age, pickiness, and perceptual attributes were predictors of preference for vegetables and examined how preference for vegetables and their perceptual attributes varies with age and pickiness. Children (8-14 years, n = 420), youth (15-34 years, n = 569), middle-aged adults (35-64 years, n = 726), and older adults (65-85 years, n = 270) were asked which vegetables they liked (or disliked) and which perceptual attributes of each vegetable they liked (or disliked). On the basis of their responses, an overall preference score and a preference sub-score for each perceptual attribute were calculated. Participants in each age group were classified into four statuses (non-, mild, moderate, and severe) according to their pickiness scores. Multiple regression analysis revealed that age and preference sub-scores for eight perceptual attributes (sweetness, sourness, bitterness, umami, pungency, orthonasal aroma, texture, and appearance) were positive predictors of overall preference score and that pickiness score and four perceptual attributes (saltiness, astringency, retronasal aroma, and aftertaste) were negative predictors. In addition, overall preference score and preference sub-scores for perceptual attributes other than saltiness increased with increasing age group and decreasing picker status; however, preference sub-scores for at least one of the six perceptual attributes (bitterness, astringency, pungency, orthonasal aroma, retronasal aroma, and aftertaste) exhibited negative values in children, youth, and pickers (mild, moderate, and severe). The increase in preference for these perceptual attributes might be an indicator of the adultization of food perception and the expansion of food acceptance.

Evaluation of card-type odor identification test for Japanese patients with olfactory disturbance.

OBJECTIVES: A card-type odor identification test, Open Essence (OE), was recently developed in order to examine olfactory function in the Japanese population. The purpose of this study was to validate the efficacy of this new test by comparison with established olfactory examinations. METHODS: We administered Jet Stream Olfactometry (JSO), an intravenous olfaction test (Alinamin test), a visual analog scale of symptoms of olfactory dysfunction, and the OE test to 50 patients with complaints of olfactory disturbance and 50 healthy volunteers. After comparison of the OE test results with those of existing olfactory examinations and the symptom scores, we tried to estimate a cutoff value compatible with the JSO threshold. RESULTS: The scores on the OE test showed significant correlations with the average detection thresholds of JSO (r = -0.738; p < 0.0001), the average recognition thresholds of JSO (r = -0.708; p < 0.0001), the symptom scores (r = 0.827; p < 0.0001), and the duration scores of the intravenous olfactory test (r = 0.673; p < 0.0001). The area under the receiver operating characteristics curve between the OE test results and the average recognition thresholds of JSO was highest when the OE test's cutoff value was set at 8. CONCLUSIONS: The OE test proved to be a useful tool for screening olfactory disturbance in the Japanese population. Scores of 8 or higher on the OE test should be judged as normal for screening.

Effects of intermittent odours on cognitive-motor performance and brain functioning during mental fatigue.

Effects of intermittent presentation of odours on cognitive-motor performance and brain activity during mental fatigue were examined using event-related brain potentials. Participants performed a Go/NoGo task for 60 min, in both odour and air control conditions. The time-on-task reaction time increase was significantly smaller in the odour condition than in the air control condition. Go- and NoGo-P3 amplitudes were larger in the presence of odours than during the air control, during mental fatigue. There were no effects of odours on error negativity (Ne)/error-related negativity (ERN) amplitude and latency. These results suggest that the presence of intermittent odours improves attentional/effortful control of response selection, and that this effect mitigates the deterioration of cognitive-motor performance during mental fatigue. PRACTITIONER SUMMARY: The present study provides evidence for a potentially effective strategy, the use of odours, to mitigate deficits in cognitive-motor performance during time-on-task. The results show that the presence of intermittent odours is an efficient tool for maintenance of attention and reaction time during a prolonged task.

Odor-Induced Taste Enhancement Is Specific to Naturally Occurring Temporal Order and the Respiration Phase.

Interaction between odor and taste information creates flavor perception. There are many possible determinants of the interaction between odor and taste, one of which may be the somatic sensations associated with breathing. We assumed that a smell stimulus accompanied by inhaling or exhaling enhances taste intensity if the order is congruent with natural drinking. To present an olfactory stimulus from the identical location during inhalation and exhalation, we blocked the gap between the tube presenting the olfactory stimulus and the nostril. Participants breathed and ingested the solution according to the instructions on the screen and evaluated the solution's taste intensity. Vanilla odor enhanced the sweet taste in both retronasal and orthonasal conditions when the order of stimuli was congruent with natural drinking, but it did not do so in either condition when they were incongruent. The results suggest that breathing is a determinant of odor-taste interaction. The methods of presenting olfactory stimuli used in this study were compared and discussed in relation to those used in previous studies. Odor-induced taste enhancement depends on the time order of smell with breathing and taste congruency in natural drinking. Taste enhancement was induced by odor in both conditions by minimizing differences in odor presentation between them.

Nostalgia evocation through seasonality-conscious purchasing behavior revealed by online survey using vegetable names.

Food can be a valuable mediator of nostalgia. Japanese food culture places a great emphasis on seasons, and thus there may be a relationship between nostalgic foods and seasonality. In this study, we hypothesized that participants who emphasized seasonality at the time of vegetable purchase (seasonality-oriented; hereafter, SO) would be more likely to feel vegetable-evoked nostalgia than those who did not (non-seasonality-oriented; hereafter, non-SO). To test this hypothesis, we administered an online survey to older Japanese adults regarding 103 representative vegetables considered to be seasonal foods. After participants selected vegetables that they had eaten, they then selected those that evoked nostalgia (hereafter, nostalgic vegetables). For each nostalgic vegetable, they evaluated the degree of nostalgia and state if a past event (autobiographical memory) was recalled. If an autobiographical memory was recalled for a certain nostalgic vegetable, nostalgia for that memory was evaluated. Comparing between SO and non-SO participants, SO participants had significantly higher numbers of nostalgic vegetables with associated autobiographical memories, as well as nostalgia for those vegetables and autobiographical memories. The results supported our hypothesis, suggesting that seasonality-conscious purchasing behavior evokes nostalgia.

Background stimulus delays detection of target stimulus in a familiar odor-odor combination.

Familiarity of odor-odor combinations is enhanced through food intake in daily life. As familiarity increases, the perceptual boundary between two odors may become ambiguous; therefore, we hypothesized that exposure to one odor would delay detection of the other in a high-familiarity combination but not in a low-familiarity combination. To test this hypothesis, we measured the speed of odor detection using two types of background stimuli (black tea odor and odorless air) and two types of target stimuli (lemon odor and almond odor). For Japanese participants, the combination of black tea and lemon odor has high familiarity, whereas the combination of black tea and almond odors has low familiarity. Reaction time for detection of target stimulus was measured by inserting a pulsed target stimulus into the flow of the background stimulus (i.e., replacing the background stimulus with the target stimulus for a short time). Reaction time for detection of lemon odor was significantly longer under the black tea odor condition than under the odorless air condition. Reaction time for detection of almond odor was similar between the black tea odor and odorless air conditions. These results are in line with the hypothesis that familiarity of an odor-odor combination affects odor detection speed. Further investigations are required to reach more robust conclusions.

Cardiac sympathetic degeneration correlates with olfactory function in Parkinson's disease.

Autonomic and olfactory dysfunctions are considered markers for preclinical diagnosis in Parkinson's disease (PD), because pathological changes in these systems can start before motor symptoms develop. We investigated whether cardiac sympathetic function and olfactory function are associated in PD. Participants comprised 40 nondemented patients with idiopathic PD, and age-matched controls. Cardiac sympathetic function was evaluated by (123) I-metaiodobenzylguanidine (MIBG) uptake, in terms of the heart to mediastinum (H/M) ratio in both early and delayed images, and the washout rate (WR). Olfactory function was evaluated using the Odor Stick Identification Test for Japanese, which evaluates the detection of 12 odorants familiar to Japanese participants. Smell identification scores were significantly lower (P < 0.001) in patients with PD than in controls. Smell identification scores correlated positively with early (P < 0.05) and delayed H/M ratios (P < 0.01), and inversely with the WR (P < 0.005) especially in patients with early PD (below 5 years of the start of motor symptoms), whereas smell identification scores did not correlate with any parameters of MIBG in the advanced PD (above 5 years of the start of motor symptoms). There was no correlation between motor symptom scores and smell identification scores, H/M ratios, or WR. The results suggest that the cardiac sympathetic nervous system might degenerate in parallel with the olfactory system in patients with early PD, and that these two systems might degenerate at a different rate of speed in advanced PD.

Expanded olfactometer for measuring reaction time to a target odor during background odor presentation.

Current olfactometers can insert a target odor into the flow of odorless air as a pulse (i.e., replace odorless air with target odor for a very short time), but no previously designed olfactometer can insert a pulse of target odor into a flow of background odor (i.e., replace background odor with target odor for a very short time). To measure reaction time to a target odor during presentation of a background odor, we developed an expanded olfactometer by adding an attachment to an existing olfactometer. We conducted three experiments to evaluate the performance of the expanded olfactometer. Additionally, four volunteers participated in trial measurement of reaction time for detection of the target odor under background odor and odorless air conditions using the expanded olfactometer. We did not observe a significant difference in gas onset time or rise time of the target odor between background and odorless air conditions. Additionally, the gas onset time and rise time of the target odor were on the order of milliseconds, whereas the gas onset time and rise time of the background odor were on the order of seconds. The reaction time was marginally significantly longer under the background odor condition than the odorless air condition. We did not observe a significant difference in gas onset time or rise time of the target odor between the existing olfactometer and our expanded olfactometer. We succeeded in developing an attachment capable of inserting a target odor into a flow of background odor. Our results revealed that performance related to the presentation of the target odor was comparable between the existing and expanded olfactometers. To more rigorously examine the effect of background odor on detection speed of target odor, we intend to increase the number of participants in the near future.

Multi-Sip Time⁻Intensity Evaluation of Retronasal Aroma after Swallowing Oolong Tea Beverage.

In most cases, a meal cannot be finished with a single bite and sip. During eating and drinking, consumers receive dynamic food perceptions from sensory attributes in foods. Thus, we performed multi-sip time⁻intensity (TI) evaluation of sensory attribute. In each of ten trials, the participant evaluated continuously the intensity of retronasal aroma for 60 s after swallowing oolong tea. We compared the TI parameters (Imax: maximum intensity, Tmax: time point at which intensity reached the maximum value, AUC: area under the TI curve, Dplateau: duration between the first and last time points with values exceeding 90% of the maximum intensity, Rinc: rate of intensity increase between the first time points with values exceeding 5% and 90% of the maximum intensity, and Rdec: rate of intensity decrease between the last time points with values exceeding 5% and 90% of the maximum intensity) and TI curves among the ten trials, and approximated each TI curve with an exponential model. Some TI parameters (Imax, Tmax, AUC, and Rinc) differed significantly between the first and subsequent trials. The TI curve was significantly lower in the first trial than in the subsequent trials, and TI curve during the time from starting the evaluation to reaching maximum intensity was significantly lower in the second trial than in the subsequent trials. The time constant of the fitted exponential function revealed that the decay of retronasal aroma intensity was slightly faster in the second through fourth trials than in the first and the fifth through tenth trials. These results indicate that olfaction might be more perceptive while consumers sip a cup of the beverage.

A high-concentration NaCl solution does not stimulate the human trigeminal nerve at the tip of the tongue.

CONCLUSION: A 3 M NaCl solution does not stimulate the trigeminal nerve in the human tongue. Objectives. In rats, the trigeminal nerve has been reported to respond when the tongue is stimulated by a solution with an NaCl concentration of 0.4 M or greater. We have attempted to clarify whether or not relatively high concentrations of NaCl stimulate the trigeminal nerves of the human tongue. MATERIALS AND METHODS: We examined four patients whose bilateral chorda tympani nerves were resected during middle ear surgeries. We performed subjective tactile and taste tests. Next, we conducted objective examinations of the subjects' tactile and gustatory functions by magnetoencephalography (MEG). RESULTS: The subjective examination confirmed that all four subjects maintained normal tactile sensory functions in their tongues and that the gustatory sensation at their lingual apexes was totally abolished. Furthermore, the objective examination of the tactile function using MEG indicated that their brain responses to trigeminal nerve stimulations were normal. Further examination using MEG failed to produce brain responses to a 3 M NaCl solution in spite of their normally functioning trigeminal nerves. Therefore, we concluded that a 3 M NaCl solution does not stimulate the trigeminal nerve at the tip of the human tongue.

[Olfactory disturbance screening with the odor stick identification test (OSIT-J) in executive checkups].

The odor stick identification test for Japanese (OSIT-J) has been shown to be useful for detecting and evaluating olfactory disturbances in Japanese people. We studied the usefulness of OSIT-J in screening for olfactory disturbances in 83 Japanese participants (49 male, 34 female) participating in an executive checkup at NTT West Kanazawa Hospital in Japan. The olfactory ability was self-reported on a grade scale. Olfactory function was then evaluated with a three-odors OSIT-J (rose, curry and sweaty socks). Participants with low self-reported olfactory ability or less-than-full scores in the three-odor test were evaluated with an additional 10 odors of OSIT-J. Eight or less points are considered to be lower than average in the 13-odor test of OSIT-J (Saito S, et al.). Eleven of the 83 participants had low self-reported olfactory ability. Four participants with a full score in the three odors test with low self-reported olfactory ability scored more than eight points in the 13-odor test. Thirty-eight participants scored less than three points in the three-odor test. Seven of 29 participants with two points in the three-odor test scored eight or less in the 13-odor test. In the 29 participants, subjects with low self-reported olfactory ability scored significantly lower scores than those without a low self-reported olfactory ability in the 13-odor test. The self-reported olfactory ability was not related to the score in the 13-odor test in the nine participants with one point or less in the three-odor test. Males scored significantly lower scores than females in the three-odor test. However, gender was not significantly related to the rate of olfactory disability estimated based on the 13-odor test. Use of a three-odor OSIT-J along with a self-administered questionnaire pertaining to olfactory disability is useful for olfactory disturbance screening during executive health checkups.

Simultaneity judgment using olfactory-visual, visual-gustatory, and olfactory-gustatory combinations.

Vision is a physical sense, whereas olfaction and gustation are chemical senses. Active sensing might function in vision, olfaction, and gustation, whereas passive sensing might function in vision and olfaction but not gustation. To investigate whether each sensory property affected synchrony perception, participants in this study performed simultaneity judgment (SJ) for three cross-modal combinations using visual (red LED light), olfactory (coumarin), and gustatory (NaCl solution) stimuli. We calculated the half-width at half-height (HWHH) and point of subjective simultaneity (PSS) on the basis of temporal distributions of simultaneous response rates in each combination. Although HWHH did not differ significantly among three cross-modal combinations, HWHH exhibited a higher value in cross-modal combinations involving one or two chemical stimuli than in combinations of two physical stimuli, reported in a previous study. The PSS of the olfactory-visual combination was approximately equal to the point of objective simultaneity (POS), whereas the PSS of visual-gustatory, and olfactory-gustatory combinations receded significantly from the POS. In order to generalize these results as specific to chemical senses in regard to synchrony perception, we need to determine whether the same phenomena will be reproduced when performing SJ for various cross-modal combinations using visual, olfactory, and gustatory stimuli other than red LED light, coumarin, and NaCl solution.

Taste of breath: the temporal order of taste and smell synchronized with breathing as a determinant for taste and olfactory integration.

Many studies have reported that subjective taste intensity is enhanced by odors which are congruent, for example a sweet taste and a vanilla odor. Some reports have suggested that subjective taste is more strongly enhanced by retronasal than by orthonasal odors; others have suggested that taste enhancements by both odor routes are identical. Differences between the two routes include the direction of airflow accompanying breath. Thus, it is possible that the order of gustatory and olfactory stimuli when breathing through either route while drinking is a determining factor for taste-odor integration. To reveal the natural relationship between taste intensity enhancement by odors and breath, synchronization of odor stimulation with the breath is necessary. Here, we examined whether the enhancement of a sweet taste is induced by a vanilla odor presented in various combinations of odor routes, immediately before and immediately after drinking. The results showed that a retronasal odor after drinking enhanced taste, but an orthonasal odor before drinking did not. The retronasal odor before drinking and the orthonasal odor after drinking did not enhance the sweet taste. These results show that congruency with the natural order of stimulus and kinetic sensation is a determining factor for odor-induced taste enhancement.

Development of a Time-Intensity Evaluation System for Consumers: Measuring Bitterness and Retronasal Aroma of Coffee Beverages in 106 Untrained Panelists.

In order to develop products that are acceptable to consumers, it is necessary to incorporate consumers' intentions into products' characteristics. Therefore, investigation of consumers' perceptions of the taste or smell of common beverages provides information that should be useful in predicting market responses. In this study, we sought to develop a time-intensity evaluation system for consumer panels. Using our system, we performed time-intensity evaluation of flavor attributes (bitterness and retronasal aroma) that consumers perceived after swallowing a coffee beverage. Additionally, we developed quantitative evaluation methods for determining whether consumer panelists can properly perform time-intensity evaluation. In every trial, we fitted an exponential function to measured intensity data for bitterness and retronasal aroma. The correlation coefficients between measured time-intensity data and the fitted exponential curves were greater than 0.8 in about 90% of trials, indicating that we had successfully developed a time-intensity system for use with consumer panelists, even after just a single training trial using a nontrained consumer. We classified participants into two groups based on their consumption of canned coffee beverages. Significant difference was observed in only AUC of sensory modality (bitterness compared with retronasal aroma) among conventional TI parameters using two-way ANOVA. However, three-way ANOVA including a time course revealed significant difference between bitterness and retronasal aroma in the high-consumption group. Moreover, the high-consumption group more easily discriminated between bitterness and retronasal aroma than the low-consumption group. This finding implied that manufacturers should select consumer panelists who are suitable for their concepts of new products.

Construction of a measurement system for simultaneity judgment using odor and taste stimuli.

BACKGROUND: The modalities examined in previous simultaneity judgment (SJ) were limited to vision, audition, and touch. By contrast, olfaction and gustation have not been addressed to date in SJ. NEW METHOD: In this study, we constructed a measurement system for performing SJ with three cross-modal, combinations of odor, taste, and light stimuli. Odor and taste stimulators were able to stimulate to only the receptors corresponding to the modalities of each stimulus, without inducing tactile sensation. Furthermore, in order to precisely calculate the time points at which stimulus reached receptors in each trial, we monitored the presented stimuli in real time. After we calculated the actual values of stimulus onset asynchrony (SOA) between standard and comparison stimuli on the basis of the records of real-time monitoring, we evaluated the temporal distributions of simultaneous response rates in each cross-modal combination. RESULTS: When we fitted a Gaussian distribution to these temporal distributions, we observed low error rates in all cross-modal combinations, as demonstrated in SJ using visual, audio, and tactile stimuli. COMPARISON WITH EXISTING METHOD(S): SJ using chemical stimuli and SJ using physical stimuli exhibit the same degree of measurement accuracy. CONCLUSIONS: We succeeded in development a high accurate measurement system for SJ using chemical stimuli. We attribute this success to the use of strict real-time monitoring of stimulus presentation.

Clinical application of a card-type odor identification test to olfactory assessment in Parkinson's disease.

OBJECTIVES: Current studies have provided valuable evidence that Parkinson's disease (PD) is closely associated with olfactory loss and that the use of olfactory testing is regarded as one of the potential screening tools for early diagnosis of PD. METHODS: Twenty-six patients with PD, age- and sex-matched 14 patients with other neurological diseases and 10 healthy controls were evaluated the sense of smell by the Open Essence (OE). RESULTS: The motor performance of the patients with PD was assessed using the Hoehn and Yahr scale. The OE scores for patients with PD were significantly lower than those with both the patients with other neurological diseases and controls. There was no significant difference of the OE scores between patients with other neurological diseases and controls. In the PD group, the OE score was not correlated with gender, smoking habit, disease duration, age at examination, or cognitive status. However, the OE scores were significantly correlated with Hoehn and Yahr stages. CONCLUSION: OE was found to be practically self-administered, time-saving, reliable, and inexpensive method for correct diagnosis of olfactory dysfunction associated with PD.