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

The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School60 enrolled

Overview

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 Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Type 2 Diabetes Mellitus Mild Cognitive Impairment

Interventions

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.

Eligibility

Sex: ALLMin age: 40 YearsMax age: 75 Years

Medical Language ↔ Plain English

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.

Locations (1)

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

Nanjing, Jiangsu, China

Outcomes

Primary Outcomes

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.

Time frame: from baseline to 4-month follow-up

Secondary Outcomes

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 \&amp;amp;gt; rest" and "scent \&amp;amp;gt; 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.

Time frame: from baseline to 4-month follow-up

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.

Data from ClinicalTrials.gov

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