Keith Kelsen’s The Scent Narrative: A Sniff of Hope in the Battle Against Alzheimer’s Disease

If you are wondering about the risk of developing Alzheimer’s disease, the answer may be right under your nose, or more accurately, inside it.  A research team at Massachusetts General Hospital (Mass Gen) has developed a series of four scent tests designed to measure early indications of Alzheimer’s. Mass Gen used a noninvasive protocol, testing the ability to recognize, remember and distinguish between scents as an early recognition of Alzheimer’s and other brain diseases that affect memory.

We know that scent is the most powerful memory experience that a human being will ever have. Humans remember 35% of what they smell vs. 15% of what they see. Scent goes directly to the hypothalamus, meaning it is also our most direct sense.  We know our sense of smell can be impacted by many different things such as Parkinson’s disease, PTSD, smoking, certain head injuries and even normal aging. The absolute key to coping and treatment is early detection.

Mass Gen researchers developed tests designed to measure early indications of Alzheimer’s disease based on an individual’s ability to recognize, remember and distinguish among odors. While Alzheimer’s disease is known to affect brain structures involved in odor perception, previous tests have not been effective screening tools since the natural ability to identify and distinguish among scents varies greatly among individuals.

These new tests can differentiate in a way that can diagnose Alzheimer’s. Certain patterns of loss in the ability to identify odors seem pronounced in Alzheimer’s, the researchers say. That’s not surprising, as odor signals from the nose must be processed in areas of the brain that are among the first to be affected by Alzheimer’s disease.

Dr. Mark W. Albers, MD, PhD, the leading researcher on the Mass Gen study, said: ” There is increasing evidence that the neurodegeneration behind Alzheimer’s starts at least 10 years before the onset of memory symptoms.”

This pre-diagnosis opens the door for anticipatory care, possible treatment and creating the mental toughness to deal with Alzheimer’s.  The estimated decade “gap” between the start of Alzheimer’s disease in the brain and the first outward manifestation of symptoms is an opportunity. If researchers can better identify individuals in the very early stages of the disease, they may be able to develop therapies and coping techniques that will slow or halt its progression.  More research surrounding scent and early detection surfaced last year at the Alzheimer’s Association International Conference (AAIC).  The Alzheimer’s Association, the sponsor, is the leading voluntary health organization in Alzheimer’s care, support and research. Their vision is a world without Alzheimer’s.

The AAIC is the world’s largest gathering of researchers from around the world focused on Alzheimer’s and other dementias. AAIC serves as a catalyst for generating new knowledge about dementia.  AAIC also fosters vital collaboration in the research community. Two additional studies done by Columbia University and released at last year’s meeting suggest doctors may eventually be able to screen people for this form of dementia by testing the ability to identify familiar odors, like smoke, coffee and raspberry.

In both studies people, who were sixty plus years of age, took a standard odor detection test. And in both cases, those who did poorly on the test were more likely to already have, (or likely to develop), problems with memory and thinking.

The whole idea is to create tests that a general clinician can use in an office setting,” says Dr. William Kreisl, a neurologist at Columbia University, where both studies were done.

The real breakthrough besides scent is affordability. Currently, any tests that can spot people in the earliest stages of Alzheimer’s are costly, painful and difficult. They include PET scans, which can detect sticky plaques in the brain, and spinal taps that measure the levels of certain proteins in spinal fluid.  The idea of an odor detection test arose, in part, from something doctors have observed for many years in patients with Alzheimer’s.

Patients will tell us that food does not taste as good,” Dr. William Kreisl stated, “The reason is often that these patients have lost the ability to smell what they eat.”

But it’s been tricky to develop a reliable and affordable screening test for odor detection. Dr. Kreisl’s team used the University of Pennsylvania Smell Identification Test, or UPSIT.

It’s basically a set of cards,” Dr. Kreisl says. “And each card has a little scratch and sniff test on it.” The cards feature familiar odors like coffee, chocolate, cinnamon and licorice.

The study found that people who had trouble identifying odors were three times more likely than other people to have memory problems. Moreover, the odor test “was able to predict memory decline in older adults about as well as the PET scan or spinal tap,” Dr. Kreisl said.

The current odor tests aren’t perfect. For one thing, other degenerative brain diseases, including Parkinson’s, can also affect odor detection. Also, the ability to smell can be diminished by smoking, certain head injuries and even normal aging. This directs researchers to look at other “biomarkers” of Alzheimer’s, to distinguish it.

But all the screening tests for Alzheimer’s are of limited value says Maria Carrillo, Chief Science Officer of the Alzheimer’s Association, “because there is still no drug that can slow or halt the disease…What we really need,” she continued,  “is to be able to use these screening tools at the same time that we have a therapeutic.”

There is an even greater “sniff of hope” as there are also new digital technologies to make the consistency required by the medical community.  These devices incorporate cartridges and dry air technology that allow for a more intensive thirty scent review.

These technologies and others may prove to give us an opportunity for early warning of symptoms that are now very subtle, and often go unnoticed by the average person.  It may be time to implement even wider diagnostics and standards testing. That protocol may show the true nature and implications of what suffers can expect over the next 10 years; all giving hope to better understanding what we are up against in the fight to cure this and other debilitating diseases.

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