An interventional study of Flavour impairment training using chewing gum group (FIT) and Olfactory training group (OT) in Anosmia, Parosmia and Phantosmia, sponsored by University of Nottingham. Completed at 1 site in United Kingdom. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-03-27.
Sponsored by University of Nottingham · Not applicable, Interventional, and Basic science
Olfactory training is developed for people who have partly or completely lost their sense of smell (olfactory dysfunction). Participants expose themselves to odours twice daily for usually 12 weeks or longer. It has been proven to effectively help people improve their sense of smell. However, when abnormal flavour perception is reported it may involve not only a dysfunctional sense of smell, but also taste and trigeminal perception (e.g. burning from chilly, cooling from mint, etc.). The stimulation of multiple sensations can theoretically enhance overall flavour perception. Therefore, we propose a pilot study to test the feasibility testing multi-sensation flavour impairment training approach using chewing gum that target sensations of smell, taste and trigeminal. This will be in comparison with an existing olfactory training approach.
Individuals (aged 18 to 65) with changed flavour perception (self-perceived, within 3 months to 2 years) will be invited to take part in this study. Participants will be randomly and evenly allocated to 3 groups which are: flavour impairment training using chewing gum (FIT), olfactory training (OT) using smelling strips, and a waiting list control group (CTR) (delaying FIT training for 12 weeks). In the first two groups, a 12-week training will be conducted. The training will be undertaken twice a day (in the morning and evening). All participants will use four flavours in a pre-determined and randomised order. One flavour of chewing gum (FIT group) or smelling strips (OT group) will be used each time. Each training session is expected to last around 3 minutes. In addition to the training, all participants will be asked to pay two visits to the lab, once before and once after completing the 12-week training, or the 12-week wait, to evaluate their flavour (smell, taste and trigeminal) perception capability. Participants will also be asked to conduct flavour perception tests at home before and after training following instructions to evaluate if their flavour perception capability has improved due to the training. The OT group and the CTR group will be offered the FIT treatment after they have undertaken the 12 weeks of their study group allocation.
Eligibility will be checked via an online questionnaire, where information of flavour perception impairment (self-report), chewing gum consumption habit, potential allergy to chewing gum/smelling bottle ingredients, and difficulty in chewing gums will be checked according to the inclusion and exclusion criteria .
Eligible participants will then be contacted via email for session time confirmation and taking consent. Upon their first visit to the lab, written consent will be taken, and training kit will be given to them.
Participants will be asked to pay two visits to the lab - to evaluate their smell perception using Sniffin' Sticks following a standard protocol (Rumeau et al., 2016) and taste perception using filter-paper disc (Nishijima et al., 2013). Upon their first lab visit, they will taste the four flavours (1 tablet per flavour) of the chewing gum that will be used in the following training. They will be given a questionnaire to indicate their perception and liking of all flavours. If there is any flavour, they find particularly disturbing that they do not wish to use to conduct the training, they have the opportunity to withdraw. Please see Fig.2. participant activities for lab visits and training at home. For both lab visits, participants will be given aromatic sticks to sniff to evaluate their Threshold, Discrimination and Identification (TDI score) of olfactory functions. Participants will also be given filter-paper discs of four tastes of sweet (sucrose), salty (sodium chloride), sour (citric acid) and bitter (quinine), and two trigeminal of cooling (menthol) and hot/burning (capsaicin) to evaluate their identification capability and threshold of taste and trigeminal sensations. Each session is expected to take up to 2 hours. On their first lab visit, participants will also be given logging-in information (by participant number) to an Xerte webpage so that they can access training protocol and their flavour selection if needed. Subsequently to the two lab visits, participants will be asked to conduct two at-home tests (once before and once after the 12-week training/waiting) to evaluate their smell, taste and trigeminal perception. For both OT and CTR groups, participants will be offered chewing gum training kit on their second lab visit.
180 studies on the registry are indexed under Anosmia; 45 are open to participants now.
This study's enrollment of 30 is below the median of 60 across 114 interventional studies indexed under Anosmia.
Browse Anosmia studies →University of Nottingham is the lead sponsor of 465 studies on the registry; 80 are open to participants now.
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Aged between 18 and 65 years male and female
Exclusion Criteria:
Physical damage in oral and/or nasal cavity due to surgery, trauma, etc.
Participants are randomly allocated once baseline data has been collected to a waiting list control group where no action will be taken.
Other: Waiting list control group
Participants are randomly allocated to chew gum twice a day for 12 weeks whilst at home.
Other: Flavour impairment training using chewing gum group (FIT)
Participants are randomly allocated to smell liquid flavouring twice a day for 12 weeks whilst at home.
Other: Olfactory training group (OT)
Participants are randomly allocated to chew gum twice a day for 12 weeks whilst at home.
Participants are randomly allocated to smell liquid flavouring twice a day for 12 weeks whilst at home.
Participants are randomly allocated once baseline data has been collected to a waiting list control group where no action will be taken.
Overall Threshold Discrimination and Identification (TDI) score using Sniffin' Sticks.
Participants will be required to sniff aromatic pens to evaluate their Threshold Discrimination and Identification of aromas at the at start and end of the study.
Time frame: From enrolment to study to after 12 weeks.
Identification of taste using four basic taste solutions
Participants are required to identify whether they can taste four different basic tastes at the start and end of the study.
Time frame: From enrolment to study to after 12 weeks.
At home smell test
Participants, whilst blindfolded, will be required to attempt to identify 5 smells commonly found in the home.
Time frame: From enrolment to study to after 12 weeks.
Training compliance
Participants will be required to submit weekly completion questionnaires online for 12 weeks.
Time frame: From enrolment to study to after 12 weeks.
Reflection on training and feasibility of the study.
Participants will be required to complete a questionnaire exploring their perceptions of the feasibility of the study.
Time frame: From enrolment to study to after 12 weeks.
Reflection on severity of abnormality in flavour perception
Participants will be required to complete a questionnaire recording their perception of the severity of their abnormality in flavour perception
Time frame: From enrolment to study to after 12 weeks.
Perception of impact on life experience of changes in flavour perception.
Participants will be required to complete a questionnaire exploring the impact of their flavour perception on their life experience.
Time frame: From enrolment to study to after 12 weeks.
Plan to share: Yes — All aspects
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report, Analytic code
Time frame: April 2025- indefinitely
Access criteria: Information will be available on request.
Ran from Oct 2024 to primary completion in Mar 2026, 16 months.
Of 50 non-industry interventional studies with no phase under Anosmia, half reached primary completion within 28 months of starting (the median), counting those still running; a quarter within 14 and three quarters within 37. This study's 16 months is below that.
Counting every sponsor, half of 50 studies reached it within 28 months; a quarter within 14 and three quarters within 37.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
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