November 15, 2025

@michaelokun

Could smell be a window into understanding Parkinson’s symptoms and predicting outcome? Olfaction refers to the brain’s ability to identify and process smells. In a new paper in the European Journal of Neurology, Yeeun Sun and colleagues describe how smell loss can reveal important clues about the many symptoms of Parkinson's. Key Points: - Olfactory dysfunction tracks w/ many non-motor issues as folks w/ worse smell showed more mood symptoms, more cognitive changes and more dysautonomia. - Limbic and caudate changes seem to emerge early as reduced dopamine transporter availability in the caudate as well as atrophy in limbic regions of brain were linked to smell loss. - Anosmia may predict worse outcomes as folks w/ complete smell loss had higher risk of freezing of gait and higher risk of future dementia. My take: The nose is the gateway to the brain. The olfactory system is like 'two train tracks' connecting the outside world to the brain. It is fascinating to think about how important this system may be in Parkinson's. Here are 5 points that resonated w/ me: 1- Smell matters more than most realize as losing it early can be a window into how Parkinson's may unfold across motor and non-motor symptoms. 2- Smell loss frequently travels w/ other symptoms including sleep changes, gastrointestinal issues and mood shifts. 3- Smell testing provides helpful clues since it may highlight changes in memory and thinking that can be tied to limbic system involvement. 4- Anosmia can forecast risk as complete smell loss may signal higher chances of freezing of gait and later cognitive difficulties. 5- Smell may one day guide care conversations as understanding olfaction could trigger personalized monitoring and prevention strategies. https://onlinelibrary.wiley.com/doi/10.1111/ene.70404 #parkinson #michaelokun #fixelinstitute