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Delayed Neurocognitive RecoveryNCT03441074

Olfactory Function and Delayed Neurocognitive Recovery

A study testing Odor Enrichment in people with Delayed Neurocognitive Recovery, run by Shanghai 10th People's Hospital 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

To explore whether odor enrichment can reduce the risk of delayed neurocognitive recovery as an intervention strategy. Read more about this study

Who is it for?
Ages 65 years and olderHealthy volunteers can take part
Conditions the study is for
Delayed Neurocognitive Recovery
What is being tested?
Odor Enrichment
Could I receive a placebo?
No, everyone receives an active treatment
How many people
131 participants
Where
1 siteChina
Study dates
1 Jan 2018to 31 Dec 2022
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 65 years and older
  • All sexes
  • Healthy volunteers accepted
  • Older adult

Who may be able to join

  • were aged at least 65 years old;
  • were expected a postoperative hospital stay of at least 7 days;
  • had American Society of Anesthesiologist (ASA) class I to II;
  • were native Mandarin speakers;
  • had been referred for a total knee or hip replacement under general anesthesia.

Who cannot join

  • were prior diagnosed of neurologic diseases by the International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10);
  • had a history of mental disorders diagnosed using the Diagnostic and Statistical Manual of Mental Disorders (DSM-5);
  • had a history of illness or surgery with nasal or sinus;
  • caught cold within one week;
  • impaired vision or auditory function which may affect the assessments;
  • were unwilling to comply with the protocol or procedures;
  • did not pass the Mini-mental State Examination (illiterates get less than 18 points, primary school graduates get less than 20 points, secondary school graduates or higher get less than 24 points) .

Trial locations and contacts

1 site in 1 country.

China1 site

  • Shanghai Tenth People's Hospital

    Shanghai, Shanghai Municipality, 200072

Other trials in China

About this study

Official title: Effects of Odor Enrichment on Delayed Neurocognitive Recovery

To explore whether odor enrichment can reduce the risk of delayed neurocognitive recovery as an intervention strategy.

Read the detailed description

Postoperative neurocognitive disorder, one of the most common postoperative complications in older adults, includes acute postoperative delirium, delayed neurocognitive recovery (within the 30 days recovery period, dNCR), and postoperative neurocognitive dysfunction (from expected recovery 30 days to 12 months). Previous studies showed that the incidence of dNCR ranged from 18% to 40% and is mainly characterized by cognitive impairment, which can develop into long-term cognitive impairment, even elevating the risk of Alzheimer's Disease (AD) related dementia and premature mortality. These symptoms can have significant adverse effects on quality of life and may increase the risk of other physical and psychological disorders, potentially impacting social stability. These statistics underscore the importance of early detection and timely intervention in mitigating the long-term effects of dNCR. Despite the significance of dNCR, effective treatment options remain elusive.

Based on these insights, previous studies have explored the impact of olfactory enrichment in animal models. Zhang et al. demonstrated that surgery and anesthesia could cause olfactory impairment, which might contribute to dNCR, while suggesting that odor enrichment, a non-pharmacological intervention, could reduce postoperative cognitive impairment in animal models. Olfactory enrichment, also known as olfactory training, is a safe and affordable treatment and may have preventative or supportive effects on olfactory function or cognitive function. Evidence supports its effectiveness in treating olfactory function from various causes and in reducing cognitive impairment.

Despite these findings, there is limited research on whether odor enrichment can serve as a mitigating strategy for dNCR among human populations. To address this gap, we conducted a clinical study to investigate whether odor enrichment could mitigate dNCR in geriatric patients and to explore the relationship between olfactory function and dNCR.

Being tested
Odor Enrichment

What participants receive

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

  • Odor EnrichmentBehavioural

    Patients in intervention group will get odor enrichment during perioperative period (3 days before the surgery and 7 days after the surgery). Odor-enriched participants were exposed daily for 24 hours to different aromatic fragrances (phenyl ethyl alcohol - rose; eucalyptol - eucalyptus; citronellal - lemon; eugenol - cloves) referred to previous studies. Odors were changed for each subject after 24 hours. According to previous studies, 10 drops of the 100% essential oil (0.5 ml) were dropped on a fabric which was placed in tea bags hanging at the hospital bedside.

Study groups in NCT03441074
Study groupRoleWhat they receive
Intervention GroupExperimentalPatients randomly assigned to intervention group will get odor enrichment during the perioperative period
Receives: Behavioral: Odor Enrichment
Non-intervention GroupNo interventionPatients randomly assigned to non-intervention group will not get any odor enrichment during the perioperative period

What is being measured

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

  1. Incidence of dNCR

    Participants underwent neuropsychological test battery, which referred to International Study Group of Postoperative Cognitive Dysfunction (ISPOCD) test battery and modified according to the characteristics of Chinese patients. The neuropsychological test battery consisted of the Hopkins Verbal Learning Test-Revised (HVLT-R), Brief Visuo-spatial Memory Test-Revised (BVMT-R), Trails Making Test (TMT), Digital Span Test (DST), HVLT-R Delayed Recall Test, HVLT-R Recognition Discrimination Index, BVMT-R Delayed Recall Test, BVMT-R Recognition Discrimination Index and Verbal Fluency Test (VFT). According to the International Study of Perioperative neurocognitive disorder definition, dNCR was diagnosed by calculating the "Z-score".

    Measured: 3 days before surgery (baseline) and 7 days after surgery (follow-up)

Secondary outcomes (1)

  1. Olfactory identification ability

    Five-odor-olfactory detection arrays were applied to test the odor identification ability of the participants three days before and then about 7 days after the surgery. This test consisted of 5 pen-shaped test sticks without labels containing five odorants including vinegar, banana, mint, rose and coal tar odor. After sniffing each stick, participants should identify each odor freely. The interval between odor presentations was about 30 seconds. The scores ranged from 0 to 5.

    Measured: 3 days before surgery (baseline) and 7 days after surgery (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 posted22 Feb 2018
  2. Study start1 Jan 2018
  3. Primary completion31 Dec 2021
  4. Study completion31 Dec 2022

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
Prevention
Allocation
Randomised
Intervention model
Parallel groups
Masking
Triple blind
Who is masked
Care provider, Investigator, Outcomes assessor
Enrolment
131 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT03441074
Sponsor's protocol ID
dsyy003
Status last verified
Jul 2025
First submitted
15 Feb 2018
Last updated
31 Jul 2025
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Publications

  • Kim MS, Yoon JH, Kim HJ, Yong SW, Hong JM. Olfactory dysfunction is related to postoperative delirium in Parkinson's disease. J Neural Transm (Vienna). 2016 Jun;123(6):589-94. doi: 10.1007/s00702-016-1555-0. Epub 2016 Apr 20.

    PubMed 27098668

  • Brown CH 4th, Morrissey C, Ono M, Yenokyan G, Selnes OA, Walston J, Max L, LaFlam A, Neufeld K, Gottesman RF, Hogue CW. Impaired olfaction and risk of delirium or cognitive decline after cardiac surgery. J Am Geriatr Soc. 2015 Jan;63(1):16-23. doi: 10.1111/jgs.13198.

    PubMed 25597555

  • Zhang C, Han Y, Liu X, Tan H, Dong Y, Zhang Y, Liang F, Zheng H, Crosby G, Culley DJ, Marcantonio ER, Shen Y, Cao JL, Xie Z. Odor Enrichment Attenuates the Anesthesia/Surgery-induced Cognitive Impairment. Ann Surg. 2023 Jun 1;277(6):e1387-e1396. doi: 10.1097/SLA.0000000000005599. Epub 2022 Jul 18.

    PubMed 35848747

  • Pieniak M, Oleszkiewicz A, Avaro V, Calegari F, Hummel T. Olfactory training - Thirteen years of research reviewed. Neurosci Biobehav Rev. 2022 Oct;141:104853. doi: 10.1016/j.neubiorev.2022.104853. Epub 2022 Sep 5.

    PubMed 36064146

Questions about this trial

What is this clinical trial studying?

A study testing Odor Enrichment in people with Delayed Neurocognitive Recovery, run by Shanghai 10th People's Hospital 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 5 inclusion and 7 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 31 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?

Incidence of dNCR (time frame: 3 days before surgery (baseline) and 7 days after surgery (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 NCT03441074, which also lists 4 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 31 Jul 2025.

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