Ear-Nose and Throat Doctor (ENT) Questions Alzheimer's Disease

Alzheimer's and loss of smell?

My father has early-stage Alzheimer's and has been saying he can't smell things as well. How could these be connected? Could it be another underlying issue? He doesn't have any other health issues.

6 Answers

There is a well-established connection between Alzheimer's and a loss or decrease in sense of smell. In fact, that can be the first symptom in some patients. Of course, other underlying nasal pathologies may be contributing and should be ruled-out by an ENT doctor. Age-related neural degeneration can also play a role. This could be multifactorial.
Impaired sense of smell has been associated with Alzheimer's and other types of dementia.
A decline in the sense of smell has been associated with early stage Alzheimer's and other neurodegenerative disorders, so it certainly may be connected in your father's case. He may also notice a decline in his ability to taste as the sense of smell and taste are closely related. There are other causes of a loss of smell including non-cancerous growths in the nose or injury to the olfactory nerve from trauma and illness which an Otolaryngologist can help you rule out by history taking and exam.
Loss of sense of smell is definitely an early finding in many neurologic diseases such as Alzheimer's. If your Dad does not have significant allergy/sinusitis-related problems (nasal congestion, recurrent sinus infections), then Alzheimer's is the most likely cause for his loss of smell. Unfortunately, the loss of smell usually worsens gradually over time. If he starts getting other symptoms such as severe headaches accompanied by nausea/vision changes, then I would recommend letting his doctor know and to get imaging of his brain (MRI).
These may or may not be connected. Most people lose the acuity of their
sense of smell with age, some more than others depending upon their
genetics. Some viruses can also damage the sense of smell. There are many
other ways that smell can be damaged, lost or attenuated. He would need to
see an Otolaryngologist for assessment.
Actually that is very common.  So much so that some people use smell loss as an early sign of dementia.  Maybe worth looking for a nasal cause, but it's probably connected.