Skip to main content

Olfactory function and discrimination ability in the elderly: a pilot study


We recently reported that subjects with a higher olfactory identification threshold for rose odor declined more in attentional ability in the elderly. This study focuses on discrimination ability and olfactory identification threshold in twelve elderly subjects living in a community (age: 80.9 ± 1.6). Olfactory function was assessed by the rose odor identification threshold. We assessed the discrimination ability by distinguishing 5 similar odor pairs. Our results showed that the subjects with a higher olfactory identification threshold (≥ 5) declined more in discrimination ability (14% ± 14%, p = 0.03) compared to those with a lower threshold (≤ 4) (averaged value set at 100%). As discrimination ability is related to the basal forebrain cholinergic system, our results suggest that olfactory impairment links to the decline in cognitive function relating the cholinergic system.


Olfactory function, especially olfactory identification ability, declines with age after 65 [1]. In addition to the age-related impairment, it is well established that olfactory function decline is among the earliest symptoms of neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease especially in the elderly [2,3,4,5]. Ability to identify odorants has been reported to decline in patients with mild cognitive impairment (MCI) and Alzheimer’s disease, which corresponds to developing cognitive impairment [6, 7]. To establish olfactory deficit as an early preclinical indicator for MCI and/or neurodegenerative diseases, such as Alzheimer’s disease, based on the olfactory impairment level, cognitive function decline should be evaluated in the elderly living in a community, using appropriate assessments.

Among the odorant items used for smell identification test, the rose odor has found to become harder to identify with the cognitive decline [7, 8]. Recently, our pilot study showed that olfactory impairment assessed by the rose odor identification threshold is linked to cognitive functional decline, especially that of attentional ability, in elderly people living in the community [9]. In addition to attention ability, discrimination ability also undergoes early impairment related to MCI and Alzheimer’s disease [10,11,12]. In basic animal studies using rats and mice, discrimination tasks using perceptually stimuli, such as visual discrimination task [13] and odor discrimination task [14, 15] are used as a cognitive test. Therefore, discrimination ability impairment is predicted to be related to olfactory function decline in the elderly.

In this study, we focused on the discrimination ability, as a cognitive function, and aimed to clarify the relationship between olfactory function and discrimination ability in the elderly.



A total of 12 elderly people (10 females and 2 males), aged 70–90 years, living in the community, participated in this study. None of the subjects had been clinically diagnosed with dementia or a history of stroke, and none had nasal congestion or a runny nose on the day of examination either.

This study analyzed the discrimination ability, accessed in the same subjects on the same day as in the study reported by Uchida et al. [9].

The study was conducted under the declaration of Helsinki and approved by the Human Research Ethics Committee of the Tokyo Metropolitan Institute of Gerontology. Written informed consent was obtained from all the participants.

Assessment of olfactory identification threshold

The olfactory ability was assessed by identifying the threshold for a rose odor using 2-phenylethyl alcohol (CAS no. 60-12-8; Tokyo Chemical Industry, Tokyo, Japan), a dominant odor compound in natural rose petals. The odorant concentration, dilution solvent, and methods for the assessment were all the same as described previously [9]. Briefly, a serial tenfold odorant dilution of eight steps, from 1 to 8 (low-to-high) concentrations, was prepared with a starting concentration of 631 mg/ml [16]. In this study, we analyzed the lowest concentration step at which the subjects correctly identified the odor. When the subjects had naming the odor difficultly, they were asked to identify the odor using a card with the correct odorant names written on it (rose flower, faint sweet, flower, or plants). The olfactory test took place in a quiet, well-ventilated room at temperature of 22–25 °C. A portable local ventilation equipment (SMST-DD-W-HD, Shonan Maruhachi S-Tech Co., Ltd., Kanagawa, Japan) was set close to the odorant bottles. Subjects were asked to avoid using perfume on the day of testing, and eating or drinking anything except for water 30-min before testing.

Discrimination ability assessment

In this study, we assessed the discrimination ability, as a cognitive function. The discrimination ability was assessed by distinguishing between 5 similar odor pairs, 4 being enantiomer substances among them (limonene, carvone, α-pinene, and menthol), used in discrimination ability assessments based on differences in odor quality in earlier human studies [17, 18]. All enantiomer substances were purchased from Tokyo Chemical Industry (Tokyo, Japan). The substances were diluted to each testing concentration using propylene glycol (Tokyo Chemical Industry) as follows: 16.9 mg/ml for ( − )-limonene (CAS no. RN5989-54-8) and ( + )-limonene (CAS no. RN5989-27-5), 96.0 mg/ml for (R)-( − )-carvone (CAS no. RN6485-40-1) and (S)-( +)-carvone (CAS no. 2244–16-8), 86.0 mg/ml for (1S)-( −)-α-pinene (CAS no. RN7785-26-4) and (1R)-( +)-α-pinene (CAS no. RN7785-70-8), and 66.7 mg/ml for ( −)-menthol (CAS no. RN2216-51–5) and ( +)-menthol (CAS no. RN15356-60–2), as reported previously [17, 18]. The fifth pair represented familiar odors in daily life, soy sauce and Worcester sauce, used without any dilution. We choose soy sauce and Worcester sauce, because they are both brown color and it is difficult to distinguish them by appearance.

The subjects were presented with a 30 ml clear glass bottle containing a 200 μl-odorant solvent-soaked paper and were asked to sniff the bottle twice. By the forced-choice triangular test procedure, the subjects were asked to compare three bottles and identify the one containing the odd stimulus. The odd stimulus was always ( −) for all 4 enantiomeric odor pairs, and soy sauce for the familiar odors. The interval between the three odor pair bottles was 3 s. The interval between the different odor pairs was 30 s. After assessing the 5 odor pairs (1st round), the 2nd round of the same 5 odor pairs (with altered odd stimulus order) was assessed following a 1-min resting period.

The number of odor pairs correctly discriminated reproducibly in both rounds was counted as the score for discrimination ability. Hence, the scores in this task ranged from 0 (the lowest score) to 5 (the highest score). By the 2-round assessment, the chance level was minimized to 11%.

Data analysis

The values were presented as the means ± SEM, unless stated otherwise. Data analysis was performed using Prism 5 (Graph-Pad Software Inc., San Diego, CA, USA). The relationship between the olfactory identification threshold and discrimination ability was analyzed by Spearman rank correlation coefficient. The Mann–Whitney test was used for the comparison of discrimination ability between two groups of different olfactory abilities (low- vs. high-threshold groups). A p value ≤ 0.05 was considered to be statistically significant.


As shown in Fig. 1a, the discrimination ability was assessed by forced-choice triangular test. All 12 subjects were able to detect the odorants used for the discrimination task. However, the ability to discriminate similar odors differed between subjects. The discrimination score of the 12 subjects was between 0 to 3. Figure 1b shows the scatter plot of the relationship between the discrimination (vertical axis, score) and olfactory (horizontal axis, threshold for identifying the rose odor) ability in all 12 subjects. All subjects were able to identify the odor between steps 2 and 7. The higher identification threshold showed a trend of lower discrimination score (r =  − 0.60, p = 0.04). In Fig. 1c, we compared the discrimination ability between the low- and the high-threshold groups (≤ 4; n = 8 and ≥ 5; n = 4, respectively). The discrimination score in the high-threshold group was 0.25 ± 0.25 (median: 0), and the value was significantly lower than that in the low-threshold group (1.8 ± 0.4, median: 2) (p = 0.03). When the discrimination score in the low-threshold group was set at 100% as an average, the score in the high-threshold group was calculated to be 14% ± 14%.

Fig. 1
figure 1

Relationship between discrimination ability and odor identification threshold. a Method testing the discrimination ability to distinguish between 5 odor pairs by comparing three bottles and identifying the one with an odd stimulus. b Scatter plot of the relationship between discrimination ability (score) and identification threshold for rose odor in all 12 subjects. The dots represent the values of an individual subject. The double circles () represents overlapping two dots. Spearman's correlation coefficient r with p value. c Comparison of discrimination ability (score) between two groups of different olfactory abilities, that is, low- and high-threshold groups (≤ 4 and ≥ 5, respectively). The horizontal lines and vertical bars show the mean and SEM values in each group. p = 0.03; the significant difference between the low- and high-threshold groups, tested by Mann–Whitney test


Our previous study showed that olfactory function decline (increase in identification threshold for rose odor) is linked to cognitive function decline, particularly that of attention ability, in elderly people living in the community [9]. In the present study, we showed the relationship between olfactory impairment and discrimination ability decline in the elderly.

As a common neural mechanism linking between olfactory dysfunction and cognitive decline in the elderly as well as in patients with neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease, possible contribution of basal forebrain cholinergic system had been suggested by the following studies. The cholinergic neurons in the basal forebrain project their fibers to the neocortex, hippocampus, and olfactory bulb, and has a key role in attention, memory, and olfactory function, respectively [19,20,21]. Our basic animal studies in rats and mice showed that the activation of the basal forebrain cholinergic neurons increases extracellular acetylcholine release and regulates regional blood flow in the neocortex, hippocampus, and olfactory bulb [22,23,24,25,26,27,28]. Research in human subjects showed that the cholinergic neurons in the basal forebrain undergo degeneration in the aging process, which is further increased by the presence of Alzheimer’s disease and Parkinson’s disease with dementia [29,30,31]. Recent publications revealed that basal forebrain atrophy precedes both entorhinal cortex atrophy and memory impairment in Alzheimer’s disease [32,33,34]. A positive association between olfactory identification ability and forebrain cholinergic pathway integrity has also been demonstrated [35].

In this study, discrimination ability was assessed by distinguishing between similar odor pairs (mainly enantiomer substances), according to previous studies [17, 18]. Animal experiments using rats and mice revealed that olfactory discrimination ability was increased by administration of physostigmine, an acetylcholine esterase inhibitor or by the optogenetic stimulation of basal forebrain cholinergic neurons projecting to the olfactory bulb [36, 37]. During the discrimination task, basal forebrain cholinergic neurons are recruited [38] and extracellular acetylcholine releases in the neocortex and hippocampus are increased [39, 40]. The aforementioned studies suggest the relation of basal forebrain cholinergic system in discriminative ability. Therefore, our present finding of linking olfactory impairment (increase in rose odor identification threshold) and discrimination ability decline could be related to impairment of basal forebrain cholinergic function.

In the present results, subjects with a higher olfactory threshold (≥ 5) declined more in the discrimination ability (14% ± 14%) compared with those subjects with a lower threshold (≤ 4) (averaged value was set at 100%). Our previous study investigated the relationship between olfactory identification threshold for rose odor and four cognitive measures [9]. Four cognitive measures were consisted of general cognitive ability assessed by Mini-Mental State Examination (MMSE) [41,42,43], its sub-domains (MMSE orientation and verbal recall 13-item subset, and 17 other items [7]), and attentional ability assessed by trail-making test part A (TMT-A) [44]. Attentional ability (performance speed of TMT-A), general cognitive ability (MMSE, total score), orientation and verbal recall (MMSE, 13-item subset), and other cognitive domains (MMSE, another 17-item subset) in the high-threshold group (≥ 5) were 73% ± 7%, 94% ± 6%, 94% ± 6%, and 95% ± 7%, respectively (when averaged value in the low-threshold group (≤ 4) was set at 100%, for each cognitive function). Considering together with our previous report [9], in the high-threshold group compared with the low-threshold group, the decline of the discrimination ability (14% ± 14%) was more marked than that of the attentional ability assessed by TMT-A (73% ± 7%) and other three cognitive measures. This may suggests that the discriminative ability assessed by distinguishing similar odor pairs sensitively measures cognitive impairment in MCI or even in earlier. Olfactory function assessment (identification threshold for rose odor) linked the discriminative ability might be useful for the early detection of Alzheimer’s disease, which could be applied to the elderly especially with mild cognitive impairment.

In this study, discriminative ability was assessed by the task distinguishing similar odor pairs. Certain previous studies reported discrimination ability decline in patients with MCI and Alzheimer’s disease, assessed by tactile angle discrimination [12] and visual object discrimination [10]. Future studies should clarify if the discrimination ability decline assessed using other sensory, such as tactile or vision, modalities could be also linked to olfactory impairment.

The limitation of this study is the small sample size. Therefore, the results should be interpreted with caution. Further studies with a larger sample size would be recommended to verify the link between olfactory identification ability and discriminative ability in the elderly. Moreover, the effects of possible confounding factors, such as age and education, should be clarified as well.


This study shows that olfactory impairment assessed by rose odor identification threshold linked to the decline in cognitive function assessed by discrimination ability, in elderly people living in the community.

Availability of data and materials

The data that support the findings of this study are available from the corresponding author on reasonable request.



Mild cognitive impairment


Mini-Mental State Examination


Trail-making test, part A


  1. Doty RL, Shaman P, Applebaum SL, Giberson R, Siksorski L, Rosenberg L (1984) Smell idenitification ability: changes with age. Science 226(4681):1441–1443.

    CAS  Article  PubMed  Google Scholar 

  2. Devanand DP, Liu X, Tabert MH, Pradhaban G, Cuasay K, Bell K, de Leon MJ, Doty RL, Stern Y, Pelton GH (2008) Combining early markers strongly predicts conversion from mild cognitive impairment to Alzheimer’s disease. Biol Psychiatry 64:871–879

    Article  Google Scholar 

  3. Murphy C (2019) Olfactory and other sensory impairments in Alzheimer disease. Nat Rev Neurol 15:11–24

    CAS  Article  Google Scholar 

  4. Sengoku R, Saito Y, Ikemura M, Hatsuta H, Sakiyama Y, Kanemaru K, Arai T, Sawabe M, Tanaka N, Mochizuki H, Inoue K, Murayama S (2008) Incidence and extent of Lewy body-related α-synucleinopathy in aging human olfactory bulb. J Neuropathol Exp Neurol 67:1072–1083

    Article  Google Scholar 

  5. Shill HA, Hentz JG, Caviness JN, Driver-Dunckley E, Jacobson S, Belden C, Sabbagh MN, Beach TG, Adler CH (2015) Unawareness of hyposmia in elderly people with and without Parkinson’s disease. Mov Disord Clin Pract 3:43–47

    Article  Google Scholar 

  6. Kouzuki M, Suzuki T, Nagano M, Nakamura S, Katsumata Y, Takamura A, Urakami K (2018) Comparison of olfactory and gustatory disorders in Alzheimer’s disease. Neurol Sci 39:321–328

    Article  Google Scholar 

  7. Umeda-Kameyama Y, Ishii S, Kameyama M, Kondo K, Ochi A, Yamasoba T, Ogawa S, Akishita M (2017) Heterogeneity of odorant identification impairment in patients with Alzheimer’s Disease. Sci Rep 7:4798.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  8. Woodward MR, Hafeez MU, Qi Q, Riaz A, Benedict RHB, Yan L, Szigeti K, Texas Alzheimer’s Research and Care Consortium (2018) Odorant item specific olfactory identification deficit may differentiate Alzheimer’s disease from aging. Am J Geriatr Psychiatry 26:835–846

    Article  Google Scholar 

  9. Uchida S, Shimada C, Sakuma N, Kagitani F, Kan A, Awata S (2020) The relationship between olfaction and cognitive function in the elderly. J Physiol Sci 70:48.

    Article  PubMed  Google Scholar 

  10. Gaynor LS, Curiel Cid RE, Penate A, Rosselli M, Burke SN, Wicklund M, Loewenstein DA, Bauer RM (2019) Visual object discrimination impairment as an early predictor of mild cognitive impairment and Alzheimer’s disease. J Int Neuropsychol Soc 25:688–698

    Article  Google Scholar 

  11. Perry RJ, Hodges JR (1999) Attention and executive deficits in Alzheimer’s disease. a critical review. Brain 122:383–404

    Article  Google Scholar 

  12. Yang J, Ogasa T, Ohta Y, Abe K, Wu J (2010) Decline of human tactile angle discrimination in patients with mild cognitive impairment and Alzheimer’s disease. J Alzheimers Dis 22:225–234

    Article  Google Scholar 

  13. Talpos JC, Fletcher AC, Circelli C, Tricklebank MD, Dix SL (2012) The pharmacological sensitivity of a touchscreen-based visual discrimination task in the rat using simple and perceptually challenging stimuli. Psychopharmacology 221:437–449

    CAS  Article  Google Scholar 

  14. Liu T, Lu J, Lukasiewicz K, Pan B, Zuo Y (2021) Stress induces microglia-associated synaptic circuit alterations in the dorsomedial prefrontal cortex. Neurobiol Stress 15:100342.

    Article  PubMed  PubMed Central  Google Scholar 

  15. Martens KM, VonderHaar C, Hutsell BA, Hoane MR (2012) A discrimination task used as a novel method of testing decision-making behavior following traumatic brain injury. J Neurotrauma 29:2505–2512

    Article  Google Scholar 

  16. Takagi SF (1989) Standardized olfactometries in Japan—a review over ten years. Chem Senses 14:25–46

    CAS  Article  Google Scholar 

  17. Laska M (2004) Olfactory discrimination ability of human subjects for enantiomers with an isopropenyl group at the chiral center. Chem Senses 29:143–152

    Article  Google Scholar 

  18. Laska M, Teubner P (1999) Olfactory discrimination ability of human subjects for ten pairs of enantiomers. Chem Senses 24:161–170

    CAS  Article  Google Scholar 

  19. Ballinger EC, Ananth M, Talmage DA, Role LW (2016) Basal forebrain cholinergic circuits and signaling in cognition and cognitive decline. Neuron 91:1199–1218

    CAS  Article  Google Scholar 

  20. D’Souza RD, Vijayaraghavan S (2014) Paying attention to smell: cholinergic signaling in the olfactory bulb. Front Synaptic Neurosci 6:21.

    Article  PubMed  PubMed Central  Google Scholar 

  21. Micheau J, Marighetto A (2011) Acetylcholine and memory: a long, complex and chaotic but still living relationship. Behav Brain Res 221:424–429

    CAS  Article  Google Scholar 

  22. Biesold D, Inanami O, Sato A, Sato Y (1989) Stimulation of the nucleus basalis of Meynert increases cerebral cortical blood flow in rats. Neurosci Lett 98:39–44

    CAS  Article  Google Scholar 

  23. Cao W-H, Inanami O, Sato A, Sato Y (1989) Stimulation of the septal complex increases local cerebral blood flow in the hippocampus in anesthetized rats. Neurosci Lett 107:135–140

    CAS  Article  Google Scholar 

  24. Hotta H (2016) Neurogenic control of parenchymal arterioles in the cerebral cortex. Prog Brain Res 225:3–39

    CAS  Article  Google Scholar 

  25. Kurosawa M, Sato A, Sato Y (1989) Stimulation of the nucleus basalis of Meynert increases acetylcholine release in the cerebral cortex in rats. Neurosci Lett 98:45–50

    CAS  Article  Google Scholar 

  26. Sato A, Sato Y (1992) Regulation of regional cerebral blood flow by cholinergic fibers originating in the basal forebrain. Neurosci Res 14:242–274

    CAS  Article  Google Scholar 

  27. Uchida S, Ito Y, Kagitani F (2019) Effects of nicotine on odor-induced increases in regional blood flow in the olfactory bulb in rats. J Physiol Sci 69:425–431

    CAS  Article  Google Scholar 

  28. Uchida S, Kagitani F (2020) Effects of nicotine on regional blood flow in the olfactory bulb in response to olfactory nerve stimulation. J Physiol Sci 70:30.

    CAS  Article  PubMed  Google Scholar 

  29. Grothe M, Heinsen H, Teipel S (2013) Longitudinal measures of cholinergic forebrain atrophy in the transition from healthy aging to Alzheimer’s disease. Neurobiol Aging 34:1210–1220

    CAS  Article  Google Scholar 

  30. Pereira JB, Hall S, Jalakas M, Grothe MJ, Strandberg O, Stomrud E, Westman E, van Westen D, Hansson O (2020) Longitudinal degeneration of the basal forebrain predicts subsequent dementia in Parkinson’s disease. Neurobiol Dis 139:104831.

    CAS  Article  PubMed  Google Scholar 

  31. Whitehouse PJ, Price DL, Struble RG, Clark AW, Coyle JT, DeLong MR (1982) Alzheimer’s disease and senile dementia: loss of neurons in the basal forebrain. Science 215:1237–1239

    CAS  Article  Google Scholar 

  32. Fernández-Cabello S, Kronbichler M, Van Dijk KRA, Goodman JA, Spreng RN, Schmitz TW, Alzheimer’s Disease Neuroimaging Initiative (2020) Basal forebrain volume reliably predicts the cortical spread of Alzheimer’s degeneration. Brain 143:993–1009

    Article  Google Scholar 

  33. Hall AM, Moore RY, Lopez OL, Kuller L, Becker JT (2008) Basal forebrain atrophy is a presymptomatic marker for Alzheimer’s disease. Alzheimers Dement 4:271–279

    Article  Google Scholar 

  34. Schmitz TW, Spreng RN (2016) Basal forebrain degeneration precedes and predicts the cortical spread of Alzheimer’s pathology. Nat Commun 7:13249.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  35. Bohnen NI, Müller MLTM, Kotagal V, Koeppe RA, Kilbourn MA, Albin RL, Frey KA (2010) Olfactory dysfunction, central cholinergic integrity and cognitive impairment in Parkinson’s disease. Brain 133:1747–1754

    Article  Google Scholar 

  36. Doty RL, Bagla R, Kim N (1999) Physostigmine enhances performance on an odor mixture discrimination test. Physiol Behav 65:801–804

    CAS  Article  Google Scholar 

  37. Nitenson AS, Nieves GM, Poeta DL, Bahar R, Rachofsky C, Mandairon N, Bath KG (2019) Acetylcholine regulates olfactory perceptual learning through effects on adult neurogenesis. iScience 22:544–556

    Article  Google Scholar 

  38. Nunez-Parra A, Cea-Del Rio CA, Huntsman MM, Restrepo D (2020) The basal forebrain modulates neuronal response in an active olfactory discrimination task. Front Cell Neurosci 14:141.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  39. Butt AE, Testylier G, Dykes RW (1997) Acetylcholine release in rat frontal and somatosensory cortex is enhanced during tactile discrimination learning. Psychobiology 25:18–33

    CAS  Article  Google Scholar 

  40. Yamamuro Y, Hori K, Tanaka J, Iwano H, Nomura M (1995) Septo-hippocampal cholinergic system under the discrimination learning task in the rat: a microdialysis study with the dual-probe approach. Brain Res 684:1–7

    CAS  Article  Google Scholar 

  41. Folstein MF, Folstein SE, McHugh PR (1975) “Mini-mental state”. A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 12:189–198

    CAS  Article  Google Scholar 

  42. Sugishita M, Koshizuka Y, Sudou S, Sugishita K, Hemmi I, Karasawa H, Ihara M, Asada T, Mihara B (2018) The validity and reliability of the Japanese version of the Mini-Mental State Examination (MMSE-J) with the original procedure of the attention and calculation task (2001). Jpn Cog Neurosci 20:91–110

    Google Scholar 

  43. Tombaugh TN, McIntyre NJ (1992) The mini-mental state examination: a comprehensive review. J Am Geriatr Soc 40:922–935

    CAS  Article  Google Scholar 

  44. Lezak MD, Howieson DB, Bigler ED, Tranel D (2012) Neuropsychological assessment, 5th edn. Oxford University Press, New York

    Google Scholar 

Download references


The authors are grateful to Ms. Sugita and Mr. Inada of a special elderly nursing home for their help in conducting this study.


This work was supported by JSPS KAKENHI Grant Numbers JP21H05348, JP21K11717 to SU.

Author information

Authors and Affiliations



SU, CS, NS, FK and SA contributed to the conception, experimental design, data interpretation. SU, NS, FK, and AK collected and analyzed data. SU drafted the manuscript; all authors edited and revised manuscript. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Sae Uchida.

Ethics declarations

Ethics approval and consent to participate

The study was conducted in accordance with the Declaration of Helsinki and approved by the Human Research Ethics Committee of the Tokyo Metropolitan Institute of Gerontology. Written informed consent was obtained from all participants.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no conflicts of interest.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Uchida, S., Shimada, C., Sakuma, N. et al. Olfactory function and discrimination ability in the elderly: a pilot study. J Physiol Sci 72, 8 (2022).

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI:


  • Odor identification threshold
  • Olfactory function
  • Cognitive function
  • Discrimination ability
  • Cholinergic system
  • Elderly people