Memory loss is nearly synonymous with dementia, but there’s another symptom of this devastating brain disorder that deserves greater attention. That was the finding of intriguing research recently presented at the Alzheimer’s Association International Conference in Los Angeles.

Background: About 90% of older adults with dementia suffer from symptoms such as agitation, aggression and hallucinations. Surprisingly, however, the most common of these so-called neuropsychiatric symptoms is one that is often unknown and overlooked.

Recent finding: Nearly half of all people with dementia suffer from apathy (a lack of feeling, interest or enthusiasm), according to a study conducted by researchers from the University of Exeter, UK.

The research team came to this conclusion after taking a close look at 20 studies involving 4,320 people with Alzheimer’s disease (the most common form of dementia). Interestingly, many of those individuals had no other indications of depression, which suggests that apathy may be clinically and biologically independent of depression.

Apathy is generally associated with more advanced dementia and can be upsetting for family members and other loved ones. This loss of emotion is often overlooked in the treatment plans of people with dementia because it is less disruptive than other symptoms, such as wandering or aggression.

Apathy also significantly affects the quality of life of people living with dementia and can have a bigger impact on their daily functioning than memory loss, the researchers explained. When apathy causes these individuals to withdraw from activities, it can accelerate cognitive decline, and there are higher mortality rates in people with apathy.

“Apathy is the forgotten symptom of dementia,” explained Clive Ballard, MD, executive dean of the University of Exeter Medical School. “Our research shows just how common apathy is in people with dementia, and we now need to understand it better so we can find effective new treatments.”

Other research has looked into ways to improve the quality of life for dementia patients suffering from apathy. For example, a study called WHELD (Well-Being and Health for People with Dementia), published in the Journal of the American Medical Directors Association, found that apathy in these patients can be improved through personalized care, social interaction and exercise.

Takeaway: If you’re concerned that a loved one with dementia has lost the motivation to pursue activities that used to excite him/her…or has stopped engaging with friends and family, contact a specialist trained in dementia care for advice.

To learn how a “dementia coach” can help you improve your loved one’s quality of life—and make your life easier, too—read here.