Sensory Enrichment for Older Adults
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ClinicalTrials.gov Identifier: NCT03914989 |
Recruitment Status :
Terminated
(Unable to complete full enrollment due to Covid pandemic.)
First Posted : April 16, 2019
Last Update Posted : March 24, 2023
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Condition or disease | Intervention/treatment | Phase |
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Cognitive Function | Other: olfactory enrichment (essential oils) | Not Applicable |
The purpose of this study is to explore sensory stimulation as a potential means of enhancing cognitive abilities. In mice, multi-odorant enrichment has been shown to increase neurogenesis in a critical memory pathway and thereby improve memory. In this clinical study, we will determine if a nightly sensory enrichment regimen using scents for 6 months can improve cognitive skills, as measured using a series of cognitive assessments and brain imaging in older adults. We also will determine if mood/mental state of mind or olfactory functioning improve following scent stimulation.
This study will enroll approximately 200 participants. Of the 200 participants in the study, 50 individuals, who are interested in participating, will have a functional Magnetic Resonance Imaging (fMRI) scan at the beginning and end of the study, which will be used to examine changes in the brain.
Participants will undergo cognitive assessments, computerized cognitive assessments, and olfactory function assessments. They will be randomly assigned to either an experimental or an active control group, and will be exposed to either a higher or lower concentration of essential oils nightly using a nebulizing fragrance diffuser, rotating through seven different scents, one per night. The exposures will continue for 6 months, after which the participants will return and undergo the same assessments conducted at the beginning of the study.
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 110 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Intervention Model Description: | Participants will be randomly assigned to either an experimental group or an active control group. |
Masking: | Double (Participant, Outcomes Assessor) |
Masking Description: | Both the participants and the assessors will be blinded to the group assignments. |
Primary Purpose: | Prevention |
Official Title: | Sensory Enrichment for Older Adults |
Actual Study Start Date : | March 8, 2019 |
Actual Primary Completion Date : | June 30, 2021 |
Actual Study Completion Date : | June 30, 2021 |
Arm | Intervention/treatment |
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Experimental: Experimental group
Individuals in this group receive exposure to a higher concentration of essential oil fragrances nightly.
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Other: olfactory enrichment (essential oils)
Participants will be exposed to either a higher or lower concentration of essential oils nightly for two hours as they are going to sleep, using a nebulizing fragrance diffuser, rotating through seven different scents, one per night. |
Placebo Comparator: Active control group
Individuals in this group receive exposure to a lower concentration of essential oil fragrances nightly.
|
Other: olfactory enrichment (essential oils)
Participants will be exposed to either a higher or lower concentration of essential oils nightly for two hours as they are going to sleep, using a nebulizing fragrance diffuser, rotating through seven different scents, one per night. |
- Evaluation of behavioral pattern separation ability [ Time Frame: 1) at Baseline and 2) after 6 months of intervention ]Change in lure discrimination index on a computerized mnemonic discrimination task.
- Evaluation of cognition [ Time Frame: 1) at Baseline and 2) after 6 months of intervention ]Change in cognitive ability will be measured using scores from a neuropsychological battery. For each subsection, a change score will be calculated using the difference between baseline and 6-month scores, and the change score will be compared between groups. Higher values indicate a better outcome.
- Evaluation of depression [ Time Frame: 1) at Baseline and 2) after 6 months of intervention ]Change in depression status using the Beck Depression Inventory.
- Evaluation of quality of life [ Time Frame: 1) at Baseline and 2) after 6 months of intervention ]Change in quality of life using the Farage Quality of Life questionnaire.
- Evaluation of olfactory function [ Time Frame: 1) at Baseline and 2) after 6 months of intervention ]Change from baseline score on the Sniffin' Sticks instrument to assess olfactory system functioning.
- Evaluation of change in brain structural connectivity [ Time Frame: 1) at Baseline and 2) after 6 months of intervention ]Change in perforant path integrity using functional Magnetic Resonance Imaging.
- Evaluation of change in brain structures [ Time Frame: 1) at Baseline and 2) after 6 months of intervention ]Change in thickness of entorhinal cortex using functional Magnetic Resonance Imaging.

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 60 Years to 85 Years (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- Are age 60-85, male or female
- Have normal cognition (determined at first assessment with cognitive testing)
- Speak/read/understand English fluently
- Have visual and auditory acuity adequate for neuropsychological and computerized testing
- Are in good general health with no disease(s) expected to interfere with the study
- Are willing and able to participate for the duration of the study and in all study procedures
- Are able to smell scents
- Are willing to refrain from using scented candles, scented oils, or air fresheners while participating in the study
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Are willing to travel to the research site for testing
If interested in functional Magnetic Resonance Imaging (fMRI),
- Are willing and able to participate in the fMRI scan.
Exclusion Criteria:
- Have known fragrance sensitivities
- Have asthma, allergies, or a fragrance sensitivity, which produces symptoms similar to those of an allergy, including runny nose, watery eyes, sneezing, or skin rash
- Have a neurologic disease such as Parkinson's disease, multiple sclerosis, brain cyst, tumor or aneurysm
- Have major health conditions such as uncontrolled diabetes mellitus, uncontrolled hypertension, nutritional deficiency or thyroid disease
- Have significant psychiatric disorders such as schizophrenia, bipolar disorder, anxiety disorder, or attention-deficit hyperactivity disorder
- Have cognitive impairment when tested at baseline (defined as a score on any neuropsychological test of 1.5 standard deviations or more outside the age norm)
- Have had alcohol or substance abuse or dependence within the past 2 years (DSM-IV criteria)
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Smoke cigarettes, e-cigarettes, cigars, marijuana, or any other substance that could produce an interfering odor for the study.
If interested in functional Magnetic Resonance Imaging (fMRI),
- MRI contraindications, (e.g. pacemakers, aneurysm clips, artificial heart valves, ear implants, metal fragments or foreign objects in the eyes, skin or body).

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03914989
United States, California | |
University of California Irvine | |
Irvine, California, United States, 92697 |
Principal Investigator: | Michael Leon, PhD | University of California, Irvine | |
Principal Investigator: | Michael Yassa, PhD | University of California, Irvine |
Responsible Party: | Michael Leon, Professor, University of California, Irvine |
ClinicalTrials.gov Identifier: | NCT03914989 |
Other Study ID Numbers: |
2014-1078 |
First Posted: | April 16, 2019 Key Record Dates |
Last Update Posted: | March 24, 2023 |
Last Verified: | February 2023 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
Memory preservation Age-related memory disorders Intervention Life quality Olfaction |