You have forgotten where you put your car keys, or you can’t seem to remember the name of your colleague you saw in the grocery store the other day. You fear the worst, that maybe these are signs of Alzheimer’s disease.

You’re not alone: a recent study asking Americans age 60 or older the condition they were most afraid of getting indicated the number one fear was Alzheimer’s or dementia (35 percent), followed by cancer (23 percent), and stroke (15 percent).

And when we hear of someone like legendary basketball Coach Pat Summitt dying on June 28 from early-onset Alzheimer’s at age 64, fears are heightened.

Memory loss is normal; Alzheimer’s is not. 

Alzheimer’s is an irreversible, progressive brain disease that slowly destroys memory and thinking skills, leading to cognitive impairment that severely affects daily living. Often the terms Alzheimer’s and dementia are used interchangeably and although the two are related, they are not the same. Dementia is a general term for the loss of memory or other mental abilities that affect daily life. Alzheimer’s is a cause of dementia, with over 70 percent of all dementia cases occurring as a result of Alzheimer’s.

The majority of Alzheimer’s cases occur in people aged 65 years or older.

Slight memory loss is a normal consequence of aging, and people therefore should not be overly concerned if they lose their keys or forget the name of a neighbor at the grocery store. If these things happen infrequently, there is scant reason to worry. You most likely do not have Alzheimer’s if you simply forgot one time where you parked upon leaving Disneyland or the local mall during the holidays.

How do you know when forgetfulness is part of the normal aging process and when it could be a symptom of Alzheimer’s? Here are 10 early signs and symptoms of Alzheimer’s disease.

A key point to consider is whether these symptoms significantly affect daily living. If so, then Alzheimer’s disease might be the cause.

For every one of these 10 symptoms of Alzheimer’s, there is also a typical age-related change that is not indicative of Alzheimer’s disease. For example, an early symptom of Alzheimer’s is memory loss including forgetting important dates or events and asking for the same information numerous times over. A typical age-related change may be sometimes forgetting names and appointments, but remembering them later.

People frequently ask if they might be afflicted with the disease if a grandparent had Alzheimer’s. The majority of Alzheimer’s cases occur in people aged 65 years or older. These individuals are classified as having what is known as late-onset Alzheimer’s. In late-onset Alzheimer’s, the cause of the disease is unknown (e.g. sporadic), although advancing age and inheriting certain genes may play an important role. Importantly, although there are several known genetic risk factors associated with late-onset Alzheimer’s, inheriting any one of these genes does not assure a prognosis of Alzheimer’s as one advances in age.

Early-onset is rare – but heredity does play an important role.

In fact less than 5 percent of the 5 million cases are a direct result of hereditary mutations (e.g. familial form of Alzheimer’s). Inheriting these rare, genetic mutations leads to what is known as early-onset Alzheimer’s, which is characterized by an earlier age of onset, often in the 40s and 50s, and is a more aggressive form of the disease that leads to a more rapid decline in memory impairment and cognition.

In general, most neurologists agree that early-onset and late-onset Alzheimer’s are essentially the same disease, apart from the differences in genetic cause and age of onset. The one exception is the prevalence of a condition called myoclonus (muscle twitching and spasm) that is more commonly observed in early-onset Alzheimer’s disease than in late-onset Alzheimer’s disease.

In addition, some studies suggest that people with early-onset Alzheimer’s decline at a faster rate than those with late-onset. Even though generally speaking the two forms of Alzheimer’s are medically equivalent, the large burden early-onset poses on the family is quite evident. Often these patients are still in the most productive phases of their life and yet the onset of the disease robs them of brain function at such a young age. These individuals may still be physically fit and active when diagnosed and more often than not still have family and career responsibilities. Therefore, a diagnosis of early-onset may have a greater negative, ripple effect on the patient as well as family members.