Alzheimer's Disease and the Peanut Butter Test
PET Scan Brain Images
Testing for Alzheimer’s Disease By Patient's Ability to Smell
There has been some media buzz about the "peanut butter test," and many hope it will aid early diagnosis of dementia and Alzheimer's. This olfactory test is a simple and low cost. It has the potential to help paramedics and clinicians identify the early onset of Alzheimer’s disease. The research was published in the Journal of Neurological Sciences (Vol 333, October 2013).
A total of 94 patients were included in the trial at The College of Medicine, University of Florida. Of these, 18 had already been diagnosed as showing early symptoms of Alzheimer’s, 24 had some mild cognitive impairment, 26 had other types of dementia (i.e., not Alzheimer’s), and 26 were a control group.
Each participant in the trial was asked to block one of their nostrils and close their eyes. A tablespoonful of peanut butter was then held at a measured distance away from their open nostril. The peanut butter was moved nearer to them in one centimeter intervals until they were able to smell it. The exercise was then repeated with the other nostril.
The researchers carried out a blind trial. In other words, they had no idea which patients were in which group (i.e., whether they already had an Alzheimer's diagnosis, etc.).
There had been previous research (published in 1989 in the International Journal of Neuroscience) that confirms the link between the olfactory system and Alzheimer’s disease. That research showed that a person’s ability to smell (or rather their inability to do so) was an early indication that they may later develop Alzheimer’s disease. This is important because patients who suffer from other types of dementia do not experience a similar decline in their ability to smell.
By 2025, the number of people age 65 and older with Alzheimer's disease is estimated to reach 7.1 million.
By 2050, the number of people age 65 and older with Alzheimer's disease may nearly triple, from 5 million to a projected 13.8 million.
In 2012, 15.4 million family and friends provided 17.5 billion hours of unpaid care to those with Alzheimer's and other dementias.— The Alzheimer’s Association (US)
What is Alzheimer's Disease?
What is Dementia?
Dementia is a broad term which covers a range of symptoms. The American Alzheimer’s Association defines dementia as “a decline in mental ability severe enough to interfere with daily life.” The most common symptoms are memory loss and an inability to focus and pay attention to one surroundings. As the condition progresses, a sufferer’s ability to reason and communicate effectively also deteriorate.
Alzheimer’s is a specific form of dementia. 50% to 80% of dementia patients have been diagnosed as having Alzheimer’s disease. It is particularly common in older dementia patients, but can affect people as young as those aged 40 to 50 years. The effects of Alzheimer’s can be devastating. In the later stages of the disease, patients are unable to recognize their nearest and dearest. They become disconnected from their surroundings and they lose the ability to communicate with their caregivers.
Care-giving and Alzheimer's disease
Have you cared for someone with Alzheimer's disease?
Dementia costs the UK over £23 billion a year, and this figure will rise to £27 billion per annum by 2018.
There are an estimated 35.6 million people living with dementia in UK and the numbers affected will double every 20 years, rising to 115.4 million in 2050.— The Alzheimer’s Society (UK)
Is there a cure for Alzheimer’s Disease or Dementia?
No, not yet. There are medications which help ease the effects of Alzheimer’s disease, but as yet there is no cure.
Pharma companies and medical scientists continue to research new drug formulations that may help slow down the symptoms of Alzheimer's and dementia. They also monitor the prevalence and progression of the disease in the hope that this will eventually lead to a cure. It is in this context that the research about a possible link between the loss of smell as an early indicator of Alzheimer’s is of great interest.
University of Florida's Peanut Butter Test
Results of the Peanut Butter Test
The results showed a significant difference between the left and right nostrils and between those patients who were already known to be suffering from the early stages of Alzheimer’s and those that were not. The lack of ability to smell with the left nostril correlated with those people who had already been diagnosed as having Alzheimer’s disease.
There was a difference of more than ten centimeters between when an Alzheimer’s patient was able to smell the peanut butter with their left nostril than the other patient categories. The olfactory nerve is located in a part of the brain that is also associated with cognitive function and memory.
The 7 Stages of Alzheimer's
Stages of Alzheimer's disease
Signs and Symptoms
1. No impairment (normal function)
No memory problems. No signs of dementia
2. Very mild cognitive decline (may be normal age-related changes or earliest signs of Alzheimer's disease)
A few memory lapses, but no clinically observed signs of dementia.
3. Mild cognitive decline (early-stage Alzheimer's can be diagnosed in some, but not all, individuals with these symptoms)
Memory difficulties are noticeable to family, friends and clinician.
4. Moderate cognitive decline (Mild or early-stage Alzheimer's disease)
Clear memory loss including recent events and own history. Mood changes.
5. Moderately severe cognitive decline (Moderate or mid-stage Alzheimer's disease)
Gaps in memory. Needs help in day-to-day activities.
6. Severe cognitive decline (Moderately severe or mid-stage Alzheimer's disease)
Memory continues to worse. Personality changes occur.
7. Very severe cognitive decline (Severe or late-stage Alzheimer's disease)
Unable to communicate or control movement.
Could this be a break-through in the treatment of Alzheimer’s?
So far, there is no known cure for Alzheimer’s disease. There are some drug treatments which can delay the progression of the disease. There are also ongoing research studies into the effects of diet, exercise and alcohol on the development of the disease. Unfortunately, often a diagnosis is made too late for either medication or a change of lifestyle to be effective. So advances in accurate tests for early diagnosis of Alzheimer’s are important.
The peanut butter test carried out by the College of Medicine, University of Florida was a pilot and further research needs to be carried out to confirm the initial results. However, if these results are repeated, then this test could become a useful aid for clinicians. The olfactory test using peanut butter is cheap and low-tech. It could be carried out in a patient’s home or in other non-medical premises. The member of staff conducting the test would need only basic training. The test is simple, quick to administer and the results are clear immediately.
Jennifer J. Stamps, Linda M. Bartoshuk, Kenneth M. Heilman. “A brief olfactory test for Alzheimer's disease.” Journal of the Neurological Sciences, Vol. 333, Oct 2013:1-2, p19–24.
Ferreyra-Moyano, H., Barragan, E. "The olfactory system and Alzheimer's disease." International Journal of Neuroscience, Dec 1989:49, p157–197.
Further Information and Helpline Numbers
For advice and information on Alzheimer's disease and dementia, you can contact the following organisations. The calls are free if you phone from within the US or UK.
- The Alzheimer's Association 1.800.272.3900 (toll-free in US)
- Alzheimer's Society National Dementia Helpline 0300 222 1122 (freephone in UK)