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Type 2 Diabetes MellitusNCT06327633

Effects of Olfactory Training on the Brain Function in T2DM Patients With Mild Cognitive Impairment

A study testing Olfactory Training in people with Type 2 Diabetes Mellitus and Mild Cognitive Impairment, run by The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School at 1 site in China.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

This is a prospective, randomized, open label, parallel, 4-month study to explore and evaluate the therapeutic effects of olfactory training on the cognitive function, olfactory function, and odor-induced brain activation in T2DM patients with mild cognitive impairment (MCI). Read more about this study

Who is it for?
Ages 40 to 75 years
What is being tested?
Olfactory Training
Could I receive a placebo?
No, everyone receives an active treatment
How many people
60 participants
Where
1 siteChina
Study dates
1 Jan 2024to 15 May 2025
Phase
Interventional
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 40 to 75 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • patients with type 2 diabetes mellitus;
  • Aged: 40 -75 years ;
  • Cognitive function assessment suggests mild cognitive impairment;
  • A stable glucose-lowering regimen for more than 2 months;
  • ≥6 years of education;
  • Right-handed.

Who cannot join

  • Cognitive function assessment suggests normal cognition or dementia;
  • Other dementia related neurological diseases or depression, Mental dysplasia, mania, schizophrenia, etc in the past 2 years; Central nervous system diseases, including brain trauma, intracranial hemorrhage, acute cerebral infarction, etc;
  • Severe sinusitis, nasal cavity and sinus polyps, skull base or nasopharyngeal tumors and other space occupying lesions;
  • Congenital diseases and traumatic history of nose, maxillofacial and skull base affecting olfaction.
  • With symptoms of upper respiratory tract infection, including nasal congestion, runny nose, fever, etc. on the day of MR examination;
  • Diabetic Acute and chronic complications, including diabetic ketoacidosis, diabetic ketoacidosis; a hyperglycemic hyperosmolar state or severe hypoglycemic coma, etc.
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  • Severe impairment of heart, liver, kidney and other organs;
  • Contraindications of MRI examination, such as implantation of metal prosthesis in vivo, claustrophobia, etc;
  • Pregnant and lactating women;
  • Receive other test drugs currently or within 3 months before participating in the project;
  • Known or suspected allergic history to essential oil;
  • Taking cognitive-related drugs.

Trial locations and contacts

1 site in 1 country.

China1 site

  • Division of Endocrinology, the Affiliated Drum Tower Hospital of Nanjing University

    Nanjing, Jiangsu, 210008

Other trials in China

About this study

Official title: A Pilot, Prospective, Randomized, Open Label, Parallel, 4-month Study to Explore and Evaluate the Therapeutic Effects of Olfactory Training on the Cognitive Function, Olfactory Function, and Odor-induced Brain Activation in T2DM Patients With Mild Cognitive Impairment.

This is a prospective, randomized, open label, parallel, 4-month study to explore and evaluate the therapeutic effects of olfactory training on the cognitive function, olfactory function, and odor-induced brain activation in T2DM patients with mild cognitive impairment (MCI).

Being tested
Olfactory Training
Keywords
Functional MRI, Cognition, Olfactory training
Medical subject headings
Diabetes Mellitus, Type 2, Cognitive Dysfunction

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Olfactory TrainingOther

    The subjects repeatedly sniffed pleasant scents of rose, lemon, clove, eucalyptus, coffee and cinnamon twice a day, 6-min per time, with focus, until the completion of the study.

Study groups in NCT06327633
Study groupRoleWhat they receive
Olfactory Training GroupExperimentalThe subjects repeatedly sniffed pleasant scents of rose, lemon, clove, eucalyptus, coffee and cinnamon twice a day, 6-min per time, with focus, until the completion of the study. Meanwhile, all patients will also continue on their existing dose and regimen of glucose- lowering schemes throughout the study. Twice weekly phone calls will be performed to evaluate the blood glucose situation, assess the safety of intervention and confirm the compliance of participants.
Receives: Other: Olfactory Training
Control GroupNo interventionThe subjects will maintain the original diet and lifestyle, and also continue on their existing dose and regimen of glucose- lowering schemes throughout the study. Phone calls will be made to evaluate the blood glucose situation.

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change of cognitive function (evaluated by MoCA score)

    Whether MoCA scores in the two groups of Type 2 diabetes mellitus patients with MCI after intervention were different from those before treatment and the difference of changes between the two groups. The MoCA scale evaluates overall cognitive function, with a total score of 30. Generally, subjects scoring ≥26 points are considered as normal cognition, while between 19-25 points as mild cognitive impairment. An extra point is added If the subject has less than 12 years of education.

    Measured: from baseline to 4-month follow-up

Secondary outcomes (3)

  1. Change of olfactory brain activation by fMRI

    Whether the activation degree of olfactory task fMRI brain area in the two groups after intervention was different from that before treatment and the difference of changes between the two groups. All patients underwent odor-induced task fMRI on a 3.0T MR scanner with 222 volumes for task fMRI and 230 volumes for resting-state fMRI. The odor-induced task consisted of "fresh air" "rest" and "scent". Odor-induced brain activation was assessed by a general linear model using Statistical Parametric Mapping 12 (SPM12) software. Following extraction of the three separate conditions "fresh air," "scent," and "rest" from the whole sequence, contrasts were made for each participant between "fresh air \> rest" and "scent \> rest." Odor-induced fMRI data were analyzed in the mask of the olfactory network, including the regions of bilateral parahippocampus, amygdala, piriform cortex, insula, orbitofrontal cortex, hippocampus, and entorhinal cortices.

    Measured: from baseline to 4-month follow-up

  2. Change of Olfactory function

    Whether the scores of olfactory threshold, identification and memory of the two groups after intervention were higher than those before treatment and the difference of changes between the two groups. Olfactory testing was performed using Olfactory Function Assessment by Computerized Testing (OLFACT) (Osmic Enterprises, Inc.). Based on the University of Pennsylvania Smell Identification Test (UPSIT), OLFACT tests were computerized, standardized, and self-administered. Higher scores indicated better ability to detect odors. Threshold testing was performed by a series of binary dilutions of n- butanol solution in light mineral oil, and scores ranged from 1 to 14. Identification and memory tests included two tasks: task A with 10 different odors, and task B with 20 odors (with 10 same odors in the task A). Each participant was asked to identify each odor from four pictures in tasks A and B and to indicate whether each was old or new in task B. There was a 10-min break in-between.

    Measured: from baseline to 4-month follow-up

  3. Change of metabolism

    The changes of glycosylated hemoglobin among the two groups before and after intervention. The level of glycosylated hemoglobin \<7% means better glucose metabolism.

    Measured: from baseline to 4-month follow-up

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted25 Mar 2024
  2. Study start1 Jan 2024
  3. Primary completion15 May 2025
  4. Study completion15 May 2025

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
None (open label)
Enrolment
60 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06327633
Sponsor's protocol ID
ZZ2024
Status last verified
Jan 2024
First submitted
18 Mar 2024
Last updated
11 Jul 2025
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Undecided

Publications

  • Zhang Z, Zhang B, Wang X, Zhang X, Yang QX, Qing Z, Lu J, Bi Y, Zhu D. Altered Odor-Induced Brain Activity as an Early Manifestation of Cognitive Decline in Patients With Type 2 Diabetes. Diabetes. 2018 May;67(5):994-1006. doi: 10.2337/db17-1274. Epub 2018 Mar 2.

    PubMed 29500313

  • Zhang Z, Zhang B, Wang X, Zhang X, Yang QX, Qing Z, Zhang W, Zhu D, Bi Y. Olfactory Dysfunction Mediates Adiposity in Cognitive Impairment of Type 2 Diabetes: Insights From Clinical and Functional Neuroimaging Studies. Diabetes Care. 2019 Jul;42(7):1274-1283. doi: 10.2337/dc18-2584. Epub 2019 May 21.

    PubMed 31221697

Questions about this trial

What is this clinical trial studying?

A study testing Olfactory Training in people with Type 2 Diabetes Mellitus and Mild Cognitive Impairment, run by The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School at 1 site in China.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 6 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 11 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change of cognitive function (evaluated by MoCA score) (time frame: from baseline to 4-month follow-up). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06327633, which also lists 2 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 11 Jul 2025.

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