Changes in Smell and Sight: Early Warning Signs of Alzheimer’s

Close up of a senior woman's face with eyes closedSeniors concerned about developing Alzheimer’s frequently focus on forgetfulness. Everyone forgets information sometimes, though, and some decline in memory is normal with old age. A new group of studies suggests that changes in smell and vision could actually be better indicators of early Alzheimer’s disease and that doctors who test for sensory decline may detect the illness earlier.

Alzheimer’s and Olfactory Function

Alzheimer’s kills brain cells, including those associated with the ability to smell and taste. One recent study evaluated 215 clinically normal seniors’ sense of smell. Researchers found that a smaller hippocampus and a thin entorhinal cortex—which are associated with memory—were linked to worse sense of smell.

A second study followed 1,037 adults without Alzheimer’s, assessing each subject three times over the course of six years. Seniors whose sense of smell deteriorated were more likely to develop dementia than seniors whose sense of smell did not deteriorate. 

Alzheimer’s and Sight

Brain cell death can affect sight just as it affects smell. Amyloid plaque deposits in the brain are a telltale sign of Alzheimer’s, but brain imaging tests to detect these plaques are expensive and are primarily used for research purposes, not as a diagnostic tool. Amyloid plaques associated with Alzheimer’s are frequently deposited in the retina, suggesting the retina could serve as a proxy for the brain in Alzheimer’s tests.

A study that evaluated 200 seniors has found that a noninvasive eye-imaging technique called retinal amyloid imaging can detect amyloid plaques in the eye. The study verified its results by following up with brain images that show brain plaques in seniors who also have retinal plaques. So far, the study has only published results from 40 participants but is expected to be completed later this year.

Of course, the aging process often undermines sight and smell, so sensory challenges don’t necessarily mean a senior has Alzheimer’s. But changes in sensory perception warrant a trip to the doctor, and soon doctors may be able to more easily, safely, and inexpensively diagnose Alzheimer’s by evaluating sensory changes.

References:

  1. Alzheimer’s Association. (2014, July 13). Smell and eye tests show potential to detect Alzheimer’s early. ScienceDaily. Retrieved from www.sciencedaily.com/releases/2014/07/140713155512.htm
  2. Wang, S. (2014, July 13). Keys to Detecting Alzheimer’s Early Could Be in the Eye. Wall Street Journal. Retrieved from http://online.wsj.com/articles/key-to-detecting-alzheimers-early-could-be-in-the-eye-1405253029

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  • JimmieRuth

    JimmieRuth

    July 14th, 2014 at 4:18 PM

    I saw this same exact story on the Today show this morning!

  • mason L.

    mason L.

    July 15th, 2014 at 11:38 AM

    I am thinking that today would be a great day to make an appointment with my eye doctor. Apparently they can see certain plaque buildups in the retina or something and they can be an indicator of the onset of Alzheimers. This is pretty fascinating stuff. I am assuming that now the race is on to find medications that can then halt the progression of the disease once the evidence is discovered.

  • josiah

    josiah

    July 17th, 2014 at 6:26 AM

    So it almost seems that this is going to need to become one more preventive type of test that will have to be done routinely especially for those who have a history of this disease or dementia in their famiies. So who gives the tests, gp doctors or do you then have to be referred out. I believe that this could be a huge stepping stone in their field and like any disease I suppose that early detection is the key to better treatment but I also worry about a few things. Who will do the testing and how much it will cost will be one thing. And then what about those who have the tests and find out that they do have early signs, then what to do about the mental health ramifications that come along with this?

  • Kellis

    Kellis

    July 18th, 2014 at 12:13 PM

    now I am really worried because I think that my sense of smell has deteriorated a lot as I have gotten older

  • Karen

    Karen

    December 5th, 2014 at 6:05 PM

    I am newly diagnosed. :-( I hope I will remember my loved ones who have already passed—friends and family, when my time comes d/t this illness. But for now, I am living, laughing and loving every moment I have left. What a party/reunion we will have!
    K

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