A Stroke Can Affect Your Sense of Smell

Did you know that decreased sensitivity to smell (hyposmia) and loss of sensitivity to smell (anosmia) could be the result of a stroke? A group of stroke survivors who were tested for smell sensitivity were less able to detect smells than people of a similar age who had not had a stroke. It is estimated that about 45% of stroke survivors experience a deficit in the ability to smell after a stroke.

Why does stroke affect smell?

The sense of smell is not usually the stereotypical handicap we think of when we think of a stroke. Overall, people tend to notice the more dramatic consequences of brain damage after a stroke, such as arm weakness or leg weakness or vision loss. People do not normally panic when they notice that they can't smell as well as they used to. But the areas of the brain that work together to integrate and understand our sense of smell can be damaged by a stroke. In fact, sometimes, a small stroke can affect the sense of smell. 

How does loss of smell affect a stroke survivor?

Loss of smell after a stroke can have a pretty big impact. Our sense of smell plays several important roles in our life. Most importantly, smell serves to alert us to unsafe conditions in our environment, such as odorous gas leaks, chemicals in our surroundings or smoke and fires, allowing us to get out of danger even if we can’t ‘see’ the source of the threat.

And, spoiling food exudes a bad odor that can make the food unappetizing, which prevents us from eating it and getting sick. So, while the loss of smell sensitivity after a stroke is not an immediate emergency or the most pressing consequence of a stroke, it is an important thing for both the stroke survivor and for caregivers to be aware of.

 

Because smell is also one of the key contributors to the overall experience of taste, the sense of smell also helps us enjoy our food. Thus, a stroke survivor might experience a decline in appetite and may not enjoy food as much as he did prior to the stroke. However, for some stroke survivors with hyposmia or anosmia, the lack of smell and taste sensation might not lead to under eating, but instead can surprisingly lead to overeating! The lack of enjoyment that normally results from the combined smell and taste of food causes some people to overeat in a futile attempt to attain gratification from the food.

Each person responds to the lack of smell sensation a little differently. Some stroke survivors use more salt or spices on their food, while others just complain that the food tastes bad. In fact, one of the consequences of altered smell function after a stroke is a symptom called dysgeusia, which is distorted taste. Dysgeusia is an unpleasant experience for some stroke survivors.

Is loss of smell a sign of stroke?

The decrease or loss of smell sensation is not normally an isolated sign of stroke.

When blood flow through a blood vessel becomes interrupted, causing brain damage that alters the sensation of smell, it normally causes other stroke symptoms as well. So, you needn't panic if you or a loved one has experienced a decline in smell sensation. But you should talk to your doctor about it because some medications and medical conditions cause a decline in your sense of smell and it is useful to have a medical evaluation to find the root of the problem.

Sources:

Olfactory dysfunction in chronic stroke patients.Wehling E, Naess H, Wollschlaeger D, Hofstad H, Bramerson A, Bende M, Nordin S, BMC Neurology, October 2015

Smell and taste dysfunction following minor stroke: a case report. Green TL, McGregor LD, King KM, Canadian Journal of Neuroscience Nursing, 2008

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