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

July 8, 2025 updated by: The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School

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).

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

60

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • China
    • Jiangsu
      • Nanjing, Jiangsu, China, 210008
        • Division of Endocrinology, the Affiliated Drum Tower Hospital of Nanjing University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • 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.

Exclusion Criteria:

  • 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.
  • 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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Olfactory Training Group
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. 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.
Other: Olfactory Training
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.
No Intervention: Control Group
The 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 the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change of cognitive function (evaluated by MoCA score)
Time Frame: from baseline to 4-month follow-up
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.
from baseline to 4-month follow-up

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change of olfactory brain activation by fMRI
Time Frame: from baseline to 4-month follow-up
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.
from baseline to 4-month follow-up
Change of Olfactory function
Time Frame: from baseline to 4-month follow-up
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.
from baseline to 4-month follow-up
Change of metabolism
Time Frame: from baseline to 4-month follow-up
The changes of glycosylated hemoglobin among the two groups before and after intervention. The level of glycosylated hemoglobin <7% means better glucose metabolism.
from baseline to 4-month follow-up

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 1, 2024

Primary Completion (Actual)

May 15, 2025

Study Completion (Actual)

May 15, 2025

Study Registration Dates

First Submitted

March 18, 2024

First Submitted That Met QC Criteria

March 18, 2024

First Posted (Actual)

March 25, 2024

Study Record Updates

Last Update Posted (Actual)

July 11, 2025

Last Update Submitted That Met QC Criteria

July 8, 2025

Last Verified

January 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • ZZ2024

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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