Dementia does more than rob people of their memories — research continues to show that this complicated condition is marked by a number of symptoms, especially at the onset. But they’re not always easy to recognize: From frequent falling to failing to recognize sarcasm, some of dementia’s early warning signs are subtle.

How can you know if you or a loved one is showing signs of Alzheimer’s disease or another form of dementia? Any change that is different from a person’s usual behavior or abilities could be a cause for concern, explains Katherine Rankin, PhD, a neuropsychologist who conducts research at the University of California San Francisco (UCSF) Memory and Aging Center. Take a look at some of the earliest signs of dementia — you may be surprised.