7 Surprising Signs of Dementia

Be on the lookout for these signs your brain health is at risk.

Medically reviewed in January 2022

Updated on June 3, 2022

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Developing dementia is a scary prospect for many people. Memory impairment is probably the best-known symptom of dementia conditions including Alzheimer’s disease, but there are other, surprising warning signs that your brain health is at risk. Be on the lookout for these lesser-known symptoms, and call a healthcare provider if you suspect you or a loved one might be developing the disorder.

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You’re having trouble chewing hard food

Are you finding it difficult to bite into an apple? That could mean you’re at risk for dementia, according to a 2012 Swedish study. Researchers examined 577 people over the age of 77 and found those who had trouble chewing hard food were at greater risk of cognitive impairment. Another study, published in 2017, linked tooth loss to dementia.

Neglecting your teeth can lead to inflammation of the gums. Though it is not proven, there is some research that points to possible connection between the two, says neurologist G. Peter Gliebus, MD, of Our Lady of Lourdes Medical Center in Camden, New Jersey. Tooth loss may also be a sign of how well you take care of yourself (or how well you’re able to take care of yourself).

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You start walking differently

Walking slower can be an early predictor of dementia. “That’s one of the signs of brain degeneration,” says Dr. Gliebus. And it’s not just walking slower—changes in stride length and variability can also predict cognitive decline.

Sometimes a walking test for someone with early Alzheimer’s or mild cognitive impairment will seem normal, until the person is asked to do something else while walking, like counting backwards or naming as many animals as they can. If their gait slows drastically, it could be a red flag.

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You’ve been sleeping more (or less)

Changes in the circadian rhythm—the body’s internal clock—can be a sign of impending dementia. “Sleep centers can be affected by brain degeneration,” says Gliebus. “That could mean hypersomnia (sleeping a lot), insomnia, fragmented sleep, or starting to sleep during the day.”

For example, in one study published in Neurology in 2017, scientists disocovered that over the course of 13 years, those who moved from under nine hours of sleep to over nine hours had more than double the risk of dementia.

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You just can’t find the words

When dementia begins to affect the areas of the brain that control language, communication can become difficult. This is called aphasia. It often begins subtly—you stumble over a word here and there—but can progress to the point where you’re almost unintelligible. People with aphasia may use the wrong words, have trouble finding the right words, mispronounce things, speak slowly or haltingly, or talk around a word—“that place where they bring you the food” instead of “restaurant." It’s important to note that some problems with word retrieval are a normal part of aging, but be on the lookout for other symptoms.

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You’re in trouble with the law

Some forms of dementia affect the parts of the brain that govern judgment, self-control, violence, and sexual behavior. As they become more compromised, you might find yourself in trouble with the law for the first time. Crimes commonly committed by people with dementia include theft, trespassing, and public urination. Aggression and violence is also a common manifestation of dementia, with one long-term study reporting that up to 96 percent of people with dementia become aggressive at some point.

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You display inappropriate sexual behavior

About 3 percent of people with dementia display inappropriate sexual behavior, according to Gliebus, because the areas of the brain influencing self-control start to degenerate. “There is no standard behavioral changes,” says Gliebus. “It depends on the disease and the parts of the brain that are affected.”

Inappropriate sexual behavior can include harassing language, public masturbation, stripping, groping, and other forms of sexual assault.

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Your Sense of Smell Is Off

Can you no longer tell the difference between two very different odors, like gasoline and lemons? That could be an early sign of Alzheimer’s, according to a June 2017 study in Neurology.

Using scratch-and-sniff tests, researchers measured the sense of smell of 300 healthy people, average age 63, at risk for Alzheimer’s due to their family history. They found that participants who had the most trouble distinguishing scents had both lower cognitive test scores and more chemicals associated with Alzheimer’s in their spinal fluid.

Loss of smell is also an early symptom of Parkinson’s disease.

Slideshow sources open slideshow sources

Fujita K, Sasaki H, et al. The Impact of Cognitive Decline and Fear of Dementia on Mental Health of Elderly People. The Gerontologist, Volume 55, Issue Suppl_2, November 2015, Pages 707–708.
Lexomboon D, Trulsson M, et al .Chewing Ability and Tooth Loss: Association with Cognitive Impairment in an Elderly Population Study. Journal of the American Geriatrics Society. October 2012. 60(100), Pages 1951-1956.
Takeuchi K, Ohara T, et al. Tooth Loss and Risk of Dementia in the Community: the Hisayama Study. Journal of the American Geriatrics Society. May 2017, 65(5); e95-e100.
Alzheimer's Society UK. Dental Care. 2022. Accessed June 3, 2022.
Rodolfo S, Wennburg A, et al. Comparison of Gait Parameters for Predicting Cognitive Decline: The Mayo Clinic Study of Aging. Journal of Alzheimer's Disease. vol. 55, no. 2, pp. 559-567, 2017.
Westwood AJ, Beiser A, et al. Prolonged sleep duration as a marker of early neurodegeneration predicting incident dementia. Neurology Mar 2017, 88 (12) 1172-1179.
Tranah GJ, Blackwell T, et al. Circadian activity rhythms and risk of incident dementia and mild cognitive impairment in older women. Annals of Neurology. November 2011. 70(5), 722–732.
Northwestern Medicine. Primary Progressive Aphasia. 2022. Accessed June 3, 2022.
Northwestern Medicine. Symptoms & Causes of PPA. 2022. Accessed June 3, 2022.
Emory University. Signs of a Normal Aging Mind. 2022. Accessed June 3, 2022.
Jaclson JL & Mallory R. Aggression and violence among elderly patients, a growing health problem. Journal of General Internal Medicine. October 2009, 24(10), 1167–1168.
Liljegren M, Naasan G, et al. Criminal behavior in frontotemporal dementia and Alzheimer disease. JAMA Neurology. March 2015. 72(3), 295–300.
De Giorgi R & Series H. Treatment of Inappropriate Sexual Behavior in Dementia. Current Treatment Options in Neurology. 2016. 18(9), 41.
Parkinson's Foundation. 10 Early Signs of Parkinson's Disease. 2022. Accessed June 3, 2022.
Lafaille-Magnan ME, Poirier J, et al.  Odor identification as a biomarker of preclinical AD in older adults at risk. Neurology. July 25, 2017. 89(4), 327–335.

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