UMIN-ICDS Clinical Trial

Public title

Study of visual background detail in an olfactory VR game and cognitive function in older adults

Acronym

Older Adult Olfactory VR Study

Scientific Title

Effects of background visual fidelity in an olfactory virtual reality game on cognitive task performance and olfactory function in older adults: a non-randomized parallel-group study

Scientific Title:Acronym

Olfactory VR Visual Fidelity Study

Region

Japan

Condition

Age-related cognitive decline

Classification by specialty

Geriatrics

Adult

Classification by malignancy

Others

Genomic information

NO

Narrative objectives1

The purpose of this study is to examine, in healthy community-dwelling older adults, whether the visual fidelity of the background environment in an olfactory virtual reality (VR) game affects changes in cognitive task performance and olfactory function following a short-term intervention, using a non-randomized parallel-group comparison. A high-visual-fidelity forest environment (Rich condition) is compared with a plain gray environment with reduced background visual information (Poor condition) to evaluate whether high visual fidelity provides an additional short-term benefit beyond the core olfactory-spatial cognitive training.

Basic objectives2

Efficacy

Basic objectives -Others

Trial characteristics_1

Exploratory

Trial characteristics_2

Explanatory

Developmental phase

Not applicable

Primary outcomes

Change in the number of correct responses on the Hiragana Rotation Task from pre-intervention to post-intervention. The baseline assessment is conducted before the first VR intervention in Session 1, and the post-intervention assessment is conducted immediately after the second VR intervention in Session 2, six days later. The pre-to-post change and the Time-by-Group interaction are compared between the Rich and Poor conditions. This is a retrospective registration, and no primary outcome was specified in a clinical trial registry before the study commenced. For this registration, this outcome is designated as the primary outcome based on its relevance to the central research question and its interpretive role in the manuscript.

Key secondary outcomes

The following outcomes are assessed before the first VR intervention in Session 1 and immediately after the second VR intervention in Session 2, six days later. Pre-to-post changes are compared between the Rich and Poor conditions.
1. Number of correct responses on the 2D Word Spatial Memory Task
2. Total score on the Missing Number Detection Task
3. Total score on the Japanese version of the Mini-Mental State Examination (MMSE-J)
4. Number of correct responses on the 2D Visual Object Spatial Memory Task
5. Number of incorrect responses on the Hiragana Rotation Task
6. Total score on the Open Essence odor identification test

Study type

Interventional

Basic design

Parallel

Randomization

Non-randomized

Randomization unit

Blinding

Open -no one is blinded

Control

Active

Stratification

NO

Dynamic allocation

NO

Institution consideration

Institution is not considered as adjustment factor.

Blocking

NO

Concealment

No need to know

No. of arms

2

Purpose of intervention

Educational,Counseling,Training

Type of intervention

Device,equipment

Behavior,custom

Interventions/Control_1

Rich condition (high visual fidelity). Participants use a Meta Quest 3 head-mounted display and an olfactory display while seated in a stabilized swivel chair. They complete an olfactory VR game for approximately 20 minutes per session, with a total of two sessions separated by six days. Participants first memorize a target odor presented for 5 seconds, navigate through the VR environment using changes in odor intensity to locate a hidden odor source, and select the odor matching the target from three alternatives. The background consists of a high-fidelity 3D forest environment containing vegetation, detailed textures, and visual landmarks. Interactive objects, spatial dimensions, locomotion speed, odor stimuli, and task procedures are identical to those in the Poor condition; only the visual fidelity of the background differs.

Interventions/Control_2

Poor condition (low visual fidelity). Participants use a Meta Quest 3 head-mounted display and an olfactory display while seated in a stabilized swivel chair. They complete an olfactory VR game for approximately 20 minutes per session, with a total of two sessions separated by six days. Participants first memorize a target odor presented for 5 seconds, navigate through the VR environment using changes in odor intensity to locate a hidden odor source, and select the odor matching the target from three alternatives. The background consists of a plain gray environment without textures, vegetation, or visual landmarks. Interactive objects, spatial dimensions, locomotion speed, odor stimuli, and task procedures are identical to those in the Rich condition; only the visual fidelity of the background differs.

Interventions/Control_3

Interventions/Control_4

Interventions/Control_5

Interventions/Control_6

Interventions/Control_7

Interventions/Control_8

Interventions/Control_9

Interventions/Control_10

Age-lower limit

60

years-old

<=

Age-upper limit

90

years-old

>=

Gender

Male and Female

Key inclusion criteria

1. Community-dwelling older adults aged 60 to 90 years
2. Individuals recruited through the Iruma Eastern Silver Human Resources Center
3. Individuals able to understand the study information and experimental procedures and provide written informed consent voluntarily
4. Individuals able to attend two experimental sessions conducted six days apart
5. Individuals able to undertake the seated VR game and cognitive assessments
6. Individuals with no apparent olfactory dysfunction affecting daily life and no recent respiratory infection, based on preliminary health screening and self-report at enrollment

Key exclusion criteria

1. Self-reported anosmia, hyposmia, or other apparent olfactory dysfunction affecting daily life
2. A recent respiratory infection at enrollment that could affect olfactory function
3. Inability to understand the study information or provide written informed consent
4. Inability to safely undertake the seated VR task or cognitive assessments
5. Inability to attend both experimental sessions conducted six days apart

Target sample size

52

Name of lead principal investigator

1st name	Takefumi
Middle name
Last name	Kobayashi

Organization

Bunkyo Gakuin University

Division name

Faculty of Human Studies

Zip code

356-8533

Address

1196 Kamekubo, Fujimino, Saitama 356-8533, Japan

TEL

049-261-6488

Email

takefumi@bgu.ac.jp

Name of contact person

1st name	Takefumi
Middle name
Last name	Kobayashi

Organization

Bunkyo Gakuin University

Division name

Faculty of Human Studies

Zip code

356-8533

Address

1196 Kamekubo, Fujimino, Saitama 356-8533, Japan

TEL

049-261-6488

Homepage URL

Email

takefumi@bgu.ac.jp

Institute

Bunkyo Gakuin University

Institute

Department

Personal name

Organization

Japan Science and Technology Agency (JST)

Organization

Division

Category of Funding Organization

Japanese Governmental office

Nationality of Funding Organization

Japan

Co-sponsor

Institute of Science Tokyo
Hosei University
University of the Arts London

Name of secondary funder(s)

Organization

Research Ethics Committee of the Faculty and Graduate School of Human Studies, Bunkyo Gakuin University

Address

1196 Kamekubo, Fujimino, Saitama 356-8533, Japan

Tel

049-261-6488

Email

hum-kyoumu@bgu.ac.jp

Secondary IDs

NO

Study ID_1

Org. issuing International ID_1

Study ID_2

Org. issuing International ID_2

IND to MHLW

Institutions

文京学院大学ふじみ野キャンパス（埼玉県）

Date of disclosure of the study information

2026

Year

08

Month

28

Day

URL releasing protocol

Publication of results

Unpublished

URL related to results and publications

Number of participants that the trial has enrolled

56

Results

Results date posted

Results Delayed

Results Delay Reason

Date of the first journal publication of results

Baseline Characteristics

Participant flow

Adverse events

Outcome measures

Plan to share IPD

Yes

IPD sharing Plan description

The deidentified data used in the analyses are planned to be made available in the Supplementary Information upon publication.

Recruitment status

Completed

Date of protocol fixation

2025

Year

06

Month

26

Day

Date of IRB

2025

Year

07

Month

11

Day

Anticipated trial start date

2025

Year

10

Month

07

Day

Last follow-up date

2025

Year

12

Month

23

Day

Date of closure to data entry

2026

Year

01

Month

22

Day

Date trial data considered complete

2026

Year

01

Month

22

Day

Date analysis concluded

2026

Year

01

Month

22

Day

Other related information

This trial was registered retrospectively. Prospective registration was not undertaken because, at study initiation, the study was not considered to require registration as a clinical trial. During editorial assessment, the journal requested trial registration; therefore, the trial was registered retrospectively to ensure transparency. The ethics approval number is 2025-016. Participant recruitment commenced on 28 August 2025, and enrolment, interventions, and assessments were conducted from 7 October to 23 December 2025. The trial and analyses had been completed at the time of registration.

Registered date

2026

Year

08

Month

28

Day

Last modified on

2026

Year

08

Month

28

Day

Link to view the page

Value
https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000071803