Using a Smell Test to Diagnose Alzheimer’s Disease

Using a Smell Test to Diagnose Alzheimer's Disease.jpeg

Alzheimer's disease (AD) pathology appears to start in the part of the brain that handles smell before subsequently spreading to additional brain regions and then, ultimately, taking over much of the rest of the brain. This led some to speculate that Alzheimer's disease may begin in the nose. Perhaps there's some environmental agent that might enter the brain through some portal in the nostrils?

This is the so-called olfactory vector hypothesis. The anatomy of the nose is well suited for the transfer of things directly into the brain, since the olfactory nerves that stick out into the nose project directly into the brain, bypassing the blood-brain barrier. The nose was actually a major infection route for the polio virus. Public health officials you started cauterizing the nasal passages of schoolchildren by spraying caustic chemicals up their noses in an effort to prevent the disease.

The concern is if people breathe in some ionized metals like aluminum dust, for example, it could be transported into the brain through these olfactory nerves at a rate of about 2 millimeters an hour, which is practically 2 inches a day. Doubt has been cast on this theory, however, by a case report of a woman born with a birth defect in which she had no smell nerves yet still developed Alzheimer's-like pathology. And so, to date, all the supporting evidence is really just circumstantial. It is clear, though, that changes in the sense of smell is among the first clinical signs of Alzheimer's, occurring during the preclinical phase--that is, before there's any noticeable cognitive decline. Could we use these changes to predict or diagnose the disease?

For years, researchers have been trying to find markers of brain illness hidden in people's ability to smell using all sorts of fancy gadgets. For example, functional MRI scans can detect differences in brain activation in response to an odor. In my video, Peanut Butter Smell Test for Alzheimer's, you can see the responses to lavender. You'll see a representation of a normal brain's responses to the odor versus an Alzheimer's brain. This unequivocally demonstrates that we can pick up changes in smell function due to Alzheimer's. But do we really need a million-dollar machine?

An ingenious group of researchers at the University of Florida discovered all we may need is some peanut butter and a ruler.

Considering that the left side of the brain primarily processes what we smell through our left nostril and the right side of our brain covers the right nostril, and understanding that Alzheimer's strikes the left side more than the right, what if you performed the following experiment: Close your eyes and mouth, breathe normally through the nose, then close one nostril, and hold a foot-long ruler out from the open nostril. Once your eyes, mouth, and one nostril are closed, open a container of peanut butter at the bottom of the ruler (one foot away from your open nostril). Move the peanut butter closer by 1 centimeter upon each exhale until you can detect the odor. Then repeat the whole procedure again using your other nostril.

This is exactly what the University of Florida researchers did with their subjects. What did they find? The normal elderly control subjects in the study smelled the peanut butter as soon as it came within an average of 18 centimeters (about 7 inches) from either nostril. It was about the same, roughly 7 inches, in the right nostrils of Alzheimer's patients. But in their left nostrils, it was a mere 2 inches! The peanut butter had to be only 2 inches away before the Alzheimer's patients could detect it through their left nostrils. This happened every single time. Indeed, the researchers found that a "left nostril impairment of odor detection was present in all the patients with probable AD." There was no left-right difference in the control group; they could smell the peanut butter when it was the same distance away from both their left and right nostrils. In the Alzheimer's group, however, there was a 12-centimeter difference.

The disparity was so great that we may be able to set a cutoff value for the diagnosis of Alzheimer's. The researchers reported that "[c]ompared to patients with other causes of dementia this nostril asymmetry of odor detection...was 100% sensitive and 100% specific for probable AD," meaning no false positives and no false negatives. Compared to healthy people, it was 100% sensitive in picking up cases of probable Alzheimer's and 92% specific. What exactly does that mean? In this study, if you had Alzheimer's, there was a 100% chance of having that wide left-right discrepancy. But, if you did have that discrepancy, the chance of having Alzheimer's was only 92%. This means there were some false positives.

The reason it's only "probable" Alzheimer's is because the only way we can really confirm someone has the disease is on autopsy. The current criteria for diagnosing Alzheimer's require an extensive evaluation, combined with fancy positron emission tomography (PET) scans and spinal taps. All of these tests are expensive and hard to get, can be invasive, and can have potential complications. On top of that, they are neither highly sensitive nor specific. The left-right nostril / peanut butter odor detection test, however, was fast, simple, non-invasive, and inexpensive. They concluded that may make peanut butter an ideal instrument for the early detection of Alzheimer's disease.

Does all this sound a bit too good to be true? It may be. A University of Pennsylvania research team was unable to replicate the results. Click here to read their paper. So at this point, the data are mixed. I'll do another post once more studies are published and we have a better handle on whether it's useful or not.

Of course, it's better to prevent Alzheimer's in the first place. Check out these videos for more information.

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: Sally Plank

Original Link

Using a Smell Test to Diagnose Alzheimer’s Disease

Using a Smell Test to Diagnose Alzheimer's Disease.jpeg

Alzheimer's disease (AD) pathology appears to start in the part of the brain that handles smell before subsequently spreading to additional brain regions and then, ultimately, taking over much of the rest of the brain. This led some to speculate that Alzheimer's disease may begin in the nose. Perhaps there's some environmental agent that might enter the brain through some portal in the nostrils?

This is the so-called olfactory vector hypothesis. The anatomy of the nose is well suited for the transfer of things directly into the brain, since the olfactory nerves that stick out into the nose project directly into the brain, bypassing the blood-brain barrier. The nose was actually a major infection route for the polio virus. Public health officials you started cauterizing the nasal passages of schoolchildren by spraying caustic chemicals up their noses in an effort to prevent the disease.

The concern is if people breathe in some ionized metals like aluminum dust, for example, it could be transported into the brain through these olfactory nerves at a rate of about 2 millimeters an hour, which is practically 2 inches a day. Doubt has been cast on this theory, however, by a case report of a woman born with a birth defect in which she had no smell nerves yet still developed Alzheimer's-like pathology. And so, to date, all the supporting evidence is really just circumstantial. It is clear, though, that changes in the sense of smell is among the first clinical signs of Alzheimer's, occurring during the preclinical phase--that is, before there's any noticeable cognitive decline. Could we use these changes to predict or diagnose the disease?

For years, researchers have been trying to find markers of brain illness hidden in people's ability to smell using all sorts of fancy gadgets. For example, functional MRI scans can detect differences in brain activation in response to an odor. In my video, Peanut Butter Smell Test for Alzheimer's, you can see the responses to lavender. You'll see a representation of a normal brain's responses to the odor versus an Alzheimer's brain. This unequivocally demonstrates that we can pick up changes in smell function due to Alzheimer's. But do we really need a million-dollar machine?

An ingenious group of researchers at the University of Florida discovered all we may need is some peanut butter and a ruler.

Considering that the left side of the brain primarily processes what we smell through our left nostril and the right side of our brain covers the right nostril, and understanding that Alzheimer's strikes the left side more than the right, what if you performed the following experiment: Close your eyes and mouth, breathe normally through the nose, then close one nostril, and hold a foot-long ruler out from the open nostril. Once your eyes, mouth, and one nostril are closed, open a container of peanut butter at the bottom of the ruler (one foot away from your open nostril). Move the peanut butter closer by 1 centimeter upon each exhale until you can detect the odor. Then repeat the whole procedure again using your other nostril.

This is exactly what the University of Florida researchers did with their subjects. What did they find? The normal elderly control subjects in the study smelled the peanut butter as soon as it came within an average of 18 centimeters (about 7 inches) from either nostril. It was about the same, roughly 7 inches, in the right nostrils of Alzheimer's patients. But in their left nostrils, it was a mere 2 inches! The peanut butter had to be only 2 inches away before the Alzheimer's patients could detect it through their left nostrils. This happened every single time. Indeed, the researchers found that a "left nostril impairment of odor detection was present in all the patients with probable AD." There was no left-right difference in the control group; they could smell the peanut butter when it was the same distance away from both their left and right nostrils. In the Alzheimer's group, however, there was a 12-centimeter difference.

The disparity was so great that we may be able to set a cutoff value for the diagnosis of Alzheimer's. The researchers reported that "[c]ompared to patients with other causes of dementia this nostril asymmetry of odor detection...was 100% sensitive and 100% specific for probable AD," meaning no false positives and no false negatives. Compared to healthy people, it was 100% sensitive in picking up cases of probable Alzheimer's and 92% specific. What exactly does that mean? In this study, if you had Alzheimer's, there was a 100% chance of having that wide left-right discrepancy. But, if you did have that discrepancy, the chance of having Alzheimer's was only 92%. This means there were some false positives.

The reason it's only "probable" Alzheimer's is because the only way we can really confirm someone has the disease is on autopsy. The current criteria for diagnosing Alzheimer's require an extensive evaluation, combined with fancy positron emission tomography (PET) scans and spinal taps. All of these tests are expensive and hard to get, can be invasive, and can have potential complications. On top of that, they are neither highly sensitive nor specific. The left-right nostril / peanut butter odor detection test, however, was fast, simple, non-invasive, and inexpensive. They concluded that may make peanut butter an ideal instrument for the early detection of Alzheimer's disease.

Does all this sound a bit too good to be true? It may be. A University of Pennsylvania research team was unable to replicate the results. Click here to read their paper. So at this point, the data are mixed. I'll do another post once more studies are published and we have a better handle on whether it's useful or not.

Of course, it's better to prevent Alzheimer's in the first place. Check out these videos for more information.

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: Sally Plank

Original Link

Treating Migraines With Lavender

 

 

 

 

 

 

 

 

Treating Migraines With Lavender

Lavender has been studied recently for several purposes, including treatment of mood and anxiety disorders (see, for example, the video I profiled in my last post, Lavender for Generalized Anxiety Disorder). Though it’s better known for its analgesic (pain-killing) properties, there hasn’t been a single documented clinical trial on lavender for the treatment of migraine headaches, which affect tens of millions of Americans every year. That is, until now: “Lavender Essential Oil in the Treatment of Migraine Headache: A Placebo-Controlled Clinical Trial.”

Migraine sufferers were asked—at the early signs of headache—to rub two to three drops of lavender essential oil onto their upper lip and inhale its vapor for a 15-min period, then score the severity of their headache for the next two hours. In the control group they did the same thing, but with drops of unscented liquid wax instead. Neither group was allowed to use any painkillers. In the lavender group 74 percent of patients had an improvement in their symptoms—significantly better than placebo.

Although lavender wasn’t directly compared to more conventional treatments and outcome measures differed, as you can see in the associated video Lavender for Migraine Headaches, lavender appears to stack up pretty well against typical migraine drugs. Lavender helped about three quarters of the time; high dose Tylenol may only work about half the time; and Ibuprofen 57% of the time. The top prescription drug, generic Imitrex, is effective 59% of the time, and the hardcore treatment they use in emergency rooms where they inject you under the skin works 70% of the time. Fortunately all of these work better than the original migraine therapy, known as trepanning, where doctors drilled holes in our head to let the evil spirits escape!

The lavender researchers concluded that the results of the study suggest that inhalation of lavender essential oil may be an effective and safe treatment modality in acute management of migraine headaches.

Migraine sufferers may also want to experiment with avoiding potential triggers such as aspartame (see my video Diet Soda and Preterm Birth). Saffron may also help with headaches (Saffron for the Treatment of PMS) as well may the avoidance of certain parasites (Pork Tapeworms on the Brain and Avoiding Epilepsy Through Diet). A note of caution, though: Pregnant migraine sufferers seeking natural remedies should be wary of advice they may get (Dangerous Advice From Health Food Store Employees).

What’s better than treating your pain with natural remedies? Not having pain in the first place! Those eating healthy diets are less likely to be on pain medications in general (Say No to Drugs by Saying Yes to More Plants). See, for example:

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death and More Than an Apple a Day.

Image credit: Avenue G / Flickr

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Using Lavender to Treat Anxiety

 

 

 

 

 

 

 

 

Using Lavender to Treat Anxiety

Lavender oil, which is distilled from lavender flowers, is often used in aromatherapy and massage. Despite its popularity, only recently have scientific investigations been undertaken into its biological activity.

While there have been small-scale studies suggesting benefit from lavender oil massage, we didn’t know if the benefit was coming from the lavender, the massage, or both. In an attempt to separate these two variables, a study was conducted in which patients in intensive care were given massages with either odorless oil or lavender oil. While patients massaged with lavender oil did say they felt less anxious and more positive, there were no objective differences found in terms of blood pressure, breathing, or heart rate. Perhaps the lavender was just been covering up the nasty hospital smells.

Subsequent studies using more sensitive tests did find physiological changes, though. We now know the scent of lavender can actually change brain wave patterns, but we didn’t know what the implications were until recently. Studies have shown the scent of lavender makes people feel better as well as perform math faster and more accurately (whereas the smell of rosemary, for example, seemed only to enable folks to do the math faster, but not necessarily with greater accuracy).

How else might one use natural means to improve cognitive performance? Check out my video Does a Drink Of Water Make Children Smarter? and for more brain hacking tips, Dietary Brain Wave Alteration.

But what if we actually eat lavender flowers? Or in the case of the study I profile in my 3-min video Lavender for Generalized Anxiety Disorder, take capsules of lavender-infused oil so as to perform a double-blind study to compare lavender head-to-head to lorazepam (Ativan).

Generalized and persistent anxiety is a frequent problem and is treated with benzodiazepines (also known as benzos or downers) like Ativan and Valium. Unfortunately, these substances can not only make one feel hungover, but they have a high potential for drug abuse and addiction. So researchers decided to give lavender a try. Ativan certainly reduced anxiety, but so did the lavender. By the end of the study you couldn’t tell which group was which, and among those that responded to either, the lavender actually seemed to work better.

The spice saffron may be aromatherapeutic as well. See Wake Up and Smell the Saffron for its role in treating PMS, above and beyond its other effects on the brain (Saffron vs. Prozac, Saffron for the Treatment of Alzheimer’s, and Saffron Versus Aricept).

Since lavender oil has no potential for drug abuse and no sedating side-effects, it appeared to be an effective and well-tolerated alternative to benzodiazepine drugs for amelioration of generalized anxiety.  

One cautionary note, however: There was a case series published in the New England Journal of Medicine entitled “Prepubertal Gynecomastia Linked to Lavender and Tea Tree Oils.” They reported cases of young boys exposed to lavender-containing lotions, soaps, hair gels, and shampoos starting to develop breasts. These effects disappeared after the products were discontinued, suggesting that lavender oil may possess hormone-disrupting activity. Indeed, when dripped on estrogen receptor positive breast cancer cells, lavender does show estrogenic effects and a decline in male hormone activity. It’s unknown, however, if similar reactions occur inside the body when lavender flowers or lavender oil is ingested.

There are some dietary components known to affect with the hormonal balance of young boys. Check out Dairy & Sexual Precocity.

More on lavender in Lavender for Migraine Headaches.

And more on dietary interventions for anxiety can be found in:

For more flower power see my blog and videos on hibiscus tea (Better Than Green Tea) and chamomile tea (Red Tea, Honeybush, & Chamomile and Chamomile Tea May Not Be Safe During Pregnancy). And hey, broccoli florets are just clusters of flower buds. See The Best DetoxBroccoli Versus Breast Cancer Stem Cells, and dozens of my other broccoli videos.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death and More Than an Apple a Day.

Image credit: tfengreen / Flickr

Original Link