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The Connection between Smell Loss and Parkinson’s Disease

The Connection between Smell Loss and Parkinson’s Disease

In this month’s feature story of Neurology Now, the American Academy of Neurology’s magazine for patients and caregivers, writer Susannah Gora takes a deeper dive into the connection between smell loss and Parkinson’s disease and how the Parkinson’s Progression Markers Initiative is looking to identify Parkinson’s in people before the onset of motor symptoms:

Enjoying the aroma of a flower may seem effortless, but it's the result of many complex interactions within the brain. During the process, air (and the tiny odor molecules it carries) enters the nostrils, passing through mucous membranes that contain millions of olfactory nerve cells. These cells then send information about the odor molecules (the scent) to the brain through olfactory nerves, which connect with parts of the brain called the olfactory bulb and the olfactory tract… In the brains of people with PD, a protein called alpha-synuclein accumulates in the olfactory system, causing damage.

Almost all newly diagnosed PD patients experience some loss of smell—and scientists now believe that this symptom begins many years before the onset of PD's motor symptoms, such as tremors and rigidity. The [PPMI] study, which involves a scratch-and-sniff smell test sent to participants in the mail, uses loss of smell as a way of identifying people who haven't yet developed PD but might in the future.

Read more about the connection between smell loss and Parkinson’s in the current issue of Neurology Now.  

DID YOU KNOW: That 1 in 2 people over the age of 60 are living with smell loss, yet 70% of people don’t know it until they are tested? Take the smell survey at

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