Essential Oil Study with 226% improvement on Rey Auditory Verbal Learning Test

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Tincup
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Essential Oil Study with 226% improvement on Rey Auditory Verbal Learning Test

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Objective: Cognitive loss in older adults is a growing issue in our society, and there is a need to develop inexpensive, simple, effective in-home treatments. This study was conducted to explore the use of olfactory enrichment at night to improve cognitive ability in healthy older adults.

Methods: Male and female older adults (N = 43), age 60–85, were enrolled in the study and randomly assigned to an Olfactory Enriched or Control group. Individuals in the enriched group were exposed to 7 different odorants a week, one per night, for 2 h, using an odorant diffuser. Individuals in the control group had the same experience with de minimis amounts of odorant. Neuropsychological assessments and fMRI scans were administered at the beginning of the study and after 6 months.

Results: A statistically significant 226% improvement was observed in the enriched group compared to the control group on the Rey Auditory Verbal Learning Test and improved functioning was observed in the left uncinate fasciculus, as assessed by mean diffusivity.

"Individuals assigned to the olfactory enrichment group were provided with an odorant diffuser (Diffuser World . ) and 7 essential oil odorants (rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender; from The Essential Oil Company, Portland, OR in identical glass vials that each fit into the diffuser. They were asked to turn on the diffuser when they went to bed, and the odorant was released into the air during the night for 2 h when they first went to sleep. They rotated through the different odorants each night. Individuals in the control group also were provided with an odorant diffuser, and they followed the same regimen as the olfactory enrichment participants, however they were provided with bottles that contained distilled water with an undetectable, de minimis amount of odorant added. Participants were instructed to change the odorant bottle daily before they went to bed, and they continued this regimen at home for 6 months. Odorant bottles for both groups were labeled with the odorant name, and they were weighed prior to distribution, to obtain a baseline weight for the filled bottles, and then weighed again after 6 months to be sure that they were in use during the study. During each participant’s first visit, they smelled each of the scents used in the study and rated them on pleasantness and intensity."

Article: A Whiff of Genius: Simple Fragrance Method Boosts Cognitive Capacity by 226%

Study Paper: Overnight olfactory enrichment using an odorant diffuser improves memory and modifies the uncinate fasciculus in older adults


J11 mentioned this without linking in this post and the next one.. Here is a quote from the second post.
J11 wrote: Wed Aug 02, 2023 8:45 pm Hmm, this aromatherapy article seems convincing.
Basically, olfactory health is cognitive health.

If the research is verified, then buying the diffuser that is expected in the fall would seem a worthwhile idea.
The idea was that the diffuser would be on for hours every night with 1 aroma.
I suppose if this were to get more fancy they might load it up with a cartridge of up to 10 aromas through the night (as the research supports the idea that more complex and more concentrated aromas seem to have a bigger influence on improving memory).
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Re: Essential Oil Study with 226% improvement on Rey Auditory Verbal Learning Test

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Results: A statistically significant 226% improvement was observed in the enriched group compared to the control group on the Rey Auditory Verbal Learning Test and improved functioning was observed in the left uncinate fasciculus, as assessed by mean diffusivity.
Thanks for sharing, Tincup. I agree that this is an exciting finding and a strategy that we can all easily use. I would warn folks to be wary of using artificial scents that may do more harm than good. I found a great infuser called Hohm, that allows me to use my own pure essential oils. I often run it with citrus (energizing) during the day and lavender (relaxing) at night. Many other popular infusers only work with the manufacturer's cartridges that include artificial/chemical fragrances.
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Re: Essential Oil Study with 226% improvement on Rey Auditory Verbal Learning Test

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Tincup wrote: Mon Sep 04, 2023 9:57 am
Methods: Male and female older adults (N = 43), age 60–85, were enrolled in the study and randomly assigned to an Olfactory Enriched or Control group. Neuropsychological assessments and fMRI scans were administered at the beginning of the study and after 6 months.
First, some positive thoughts on this study:
  • Olfactory diffusers, if proven effective, would be a low-cost means of promoting slow-wave deep sleep and improving mental alertness and verbal memory and would be acceptable to widely diverse groups.
  • I've administered and scored the California Verbal Learning Test, which is very similar to the Rey Auditory Verbal Learning Test (RAVLT) used in this study. Instructions are "repeat as many of the [15] words as you can in any order." These are tests of attention, short-term verbal memory (30-60 seconds), consolidated memory (remembering more words each time, so you only focus on the ones you didn't remember) and long-term memory (20-25 minutes later, after "distraction" tasks). No one finds this a fun test but it does give some useful information, when used with other cognitive tests.
  • The results show some trends, and one test (the 5th repetition) showed a clear difference.
But the devil is in the details.
  • Both groups did slightly BETTER the first time they heard a new list of words 6 months than they did at baseline. [This is a cognitive strength (remembering a prior task) termed "the practice effect" in research. It disappears over time in people with MCI and is generally absent in people with AD.] But the Control group gained slightly MORE than the exposure Group on the first trial, and also performed better than the Exposure group on the second trial. Both groups had similar attention and short-term memory skills, after 6 months of diffuser use by the Exposure group.
  • Something happens after the third repetition: the Exposure group shows consolidation from short-term to long-term memory, a pre-requisite to remembering something 20 minutes later. The 4th and 5th time they hear the list, the Exposure group improves over their baseline performance, while the Control group does a little worse.
  • This looks like long-term memory is clearly better in the Exposure Group. Except that the 226% difference appears to come largely from the only 2 men in the Control Group.
For the RAVLT, Control females (N = 9) decreased their scores by 0.1 points and Control males (N = 2) decreased their scores by 3.5 points, Enriched females (N = 8) increased their scores by 0.88 points and Enriched males (N = 4) increased their scores by 1 point.
That gender difference is a clear outlier, which call for more explanation. There's no mention of asking each group if they thought they had the fragrances or the saline. Did these men figure out they didn't have the diffuser and so didn't expect to do well on the test? Or are these two men a showing a real difference from the men and women in the treatment group? But why only the men?

Here's the key issue in all of these details: The researchers repeated the RAVLT on only 23 out of 43 people in the baseline group-an attrition rate of 53% due to COVID. They then compared those 23 people to the MRI results for all 43 people who were allowed to take a repeat MRI from 6 to 17 months post-baseline--almost a full year later than planned and possibly significant in their results.
Due to the COVID-19 pandemic, the UCI campus was closed in April 2020 ...As a result, participants ....were encouraged to continue their sensory enrichment, however, compliance was variable...
Accordingly for cognitive assessment, we only included individuals...prior to the UCI shutdown (a total of 11 controls and 12 enriched).
For the MRI analysis, we included everyone who returned to campus for their follow-up MRI despite the difference in time (range: 6–17 months; a total of 23 controls and 20 enriched).
The hypothesis that olfactory therapy at night helps sleep and long-term verbal memory is exciting. Results on 43 people might have supported a larger trial. But I think a biostatistician would say drawing sweeping conclusions from this study of one group of 10 against another group of 11 after 6 months doesn't pass the smell test.

Study Paper: Overnight olfactory enrichment using an odorant diffuser improves memory and modifies the uncinate fasciculus in older adults
4/4 and still an optimist!
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Re: Essential Oil Study with 226% improvement on Rey Auditory Verbal Learning Test

Post by circular »

NF52 thanks for another great study breakdown. I don’t have the time or experience to do what you can do, and I find it so helpful.

My concern with diffusers (and I’m sketchy on this) is that many EOs, if not all, emit VOCs, and despite being a natural component of plants, EOs are highly concentrated and, especially when diffused inside, aren’t like catching a whiff of a flower as you walk by in the open air.

Marketers like to appeal to buyers’ confidence in the historical use of various herbs and oils since ancient times, but I read that the technology we have to make concentrated EO’s (I guess distillation?) wasn’t developed until about, if I recall correctly, the 1700s.

So while I’m not sure that diffusing could have unintended adverse effects, I’m concerned enough that I won’t diffuse EOs in my home. VOCs are not always good for the lungs.

I do sometimes sniff from a bottle to help steer my consciousness in a desired direction, but not if I can easily get there another way. EOs are sort of backup plan in my toolkit.

I hope future work in this area includes investigation into side effects and doesn’t just assume they are safe, or safe fir all.
ApoE 3/4 > Thanks in advance for any responses made to my posts.
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Re: Essential Oil Study with 226% improvement on Rey Auditory Verbal Learning Test

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But I think a biostatistician would say drawing sweeping conclusions from this study of one group of 10 against another group of 11 after 6 months doesn't pass the smell test.
I agree that this needs more research, but I want to clarify a few things. Both groups got the essential oil, there was no saline. The control group got a highly diluted scent while the experimental group were exposed to high strength oil. Both groups had to use the diffuser.

One of the most interesting findings is that those with the 226% increase in cognitive performance also had brain scans that also revealed a significant change in the anatomical areas of the brain involved in memory and thinking within the enriched group. The imaging scans revealed better integrity in the brain pathway called the left uncinate fasciculus, which connects the medial temporal lobe to the decision-making prefrontal cortex. These areas tend to be less robust with age. The enriched group also reported undisturbed good quality sleep which has previously been shown with EOs.
I hope future work in this area includes investigation into side effects and doesn’t just assume they are safe, or safe fir all.
Another good point. I wonder if VOCs from EOs with synthetic ingredients instead of actual plant materials would be harmful vs. beneficial? My guess is that the actual concentration of the oil would be critical.
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Re: Essential Oil Study with 226% improvement on Rey Auditory Verbal Learning Test

Post by circular »

Julie G wrote: Sat Sep 16, 2023 5:06 am
I hope future work in this area includes investigation into side effects and doesn’t just assume they are safe, or safe fir all.
Another good point. I wonder if VOCs from EOs with synthetic ingredients instead of actual plant materials would be harmful vs. beneficial? My guess is that the actual concentration of the oil would be critical.
I think so too, and that’s the concentration in the bottle as well as in the room and physiology, factoring in room size, how long the EOs are diffused, how deeply they’re inhaled … I wish I felt more confidence in the big picture. I do hope I’m just too stuck in worry these days to see straight, but I guess years of research will tell.
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Re: Essential Oil Study with 226% improvement on Rey Auditory Verbal Learning Test

Post by circular »

This is the study I read some years back that made me cautious:

https://link.springer.com/article/10.10 ... 018-0606-0
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Re: Essential Oil Study with 226% improvement on Rey Auditory Verbal Learning Test

Post by circular »

And this article takes a conventional but nicely balanced approach when it comes to EOs and lung health:

https://parade.com/911248/jenniferlarso ... for-lungs/
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