If you can’t smell your shampoo and soap in the shower, it might be time to schedule an appointment with a neurologist.
Anosmia, or the loss of sense of smell, has been linked to dementia and can be an early sign of Alzheimer’s disease, Lewy Body dementia, and Parkinson’s disease.
This symptom can come on years, even a decade, before a person receives a dementia diagnosis.
A loss of smell doesn’t necessarily mean dementia, and there are more common reasons for a decrease in the sense, like the common cold, flu, sinus infections, allergies, and Covid.
Dementia is neurodegenerative, meaning it causes continuous brain atrophy over time.
And because our sense of smell and other senses are configured in the brain, the area that governs smell can become permanently damaged.
Around three percent of Americans over 40 lack a sense of smell, but exact figures are difficult to come by due to a lack of research.
Additionally, like dementia, the odds of experiencing a loss of sense of smell increase exponentially with age.
A lack of a sense of smell could be an early sign of dementia/Alzheimer’s disease. As the brain atrophies due to the neurodegenerative disorder, the area of the brain that dictates our sense of smell deteriorates
About four percent of people aged 40 to 49 experience olfactory dysfunction, while the rate increases to 10 percent for those aged 50 to 59.
In the 60 to 69 age group, 13 percent lack a sense of smell, and the prevalence rises further to 25 percent for people aged 70 to 79.
By the age of 80 and older, nearly 39 percent of individuals are affected by this condition.
Dr. Fouzia Siddiqui, MD, neurologist and sleep center medical director for Sentara RMH Medical Center, said: ‘An increased risk of cognitive decline and Alzheimer’s disease dementia has been identified in subjects with olfactory dysfunction.
‘Odor identification has been identified as a useful screening tool that predicts conversion from mild cognitive impairment to Alzheimer’s disease dementia.’
A 2023 study followed more than 2,400 participants for an average of nearly eight years, tracking their sense of smell and its relationship with dementia.
Anosmia, or complete loss of smell, was found to be associated with nearly a threefold higher risk of developing dementia.
Hyposmia, which refers to a reduced sense of smell, was linked to a 1.76 to 1.85 times increased risk of dementia.
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In addition, individuals who self-reported severe olfactory dysfunction were also at a higher risk, with those reporting very poor smell function showing a 2.56-fold increased risk of developing dementia.
Dr. Meredith Bock, MD, a board-certified neurologist and chief medical officer at Remo Health, said: ‘The process of neurodegeneration that causes dementia can also affect sensation and sensory processing related to smell, making it harder for them to recognize familiar scents like their favorite shampoo or body wash.’
If this problem is distressing, particularly in an older adult, it’s a good idea to seek out professional help from a doctor, Dr Bock said. Once in the doctor’s office, they can order cognitive tests to see if neurological decline could be causing the lack of smell.
Dr Bock added: ‘Unfortunately, if the loss of smell and taste is due to a neurodegenerative disorder, such as Alzheimer’s disease or Parkinson’s disease, it does not come back.’
