Memory loss is a prominent symptom of Alzheimer’s disease, but that’s only one of many signs of the disorder.

The disease, which affects 5.8 million people in the US, often presents as forgetfulness, irritability and trouble communicating.

Earlier this month, researchers said they’d uncovered another sign of the illness: imprudent altruism.

The new findings suggested that elderly people who were more willing to give away money to strangers are at a higher risk of developing the neurodegenerative disease.

“Trouble handling money is thought to be one of the early signs of Alzheimer’s disease, and this finding supports that notion,” said Duke Han, lead study author and professor of neuropsychology, in a statement.

The study is the latest to shed light on the mysterious disease. Read on to learn more about Alzheimer’s difficult to discern symptoms:

Giving out money

Compared to younger generations, older people are more likely to be victimized by online phishing scams, which could be a sign of Alzheimer’s in some.

Researchers at both the University of Southern California and Bar-Ilan University University in Israel found a link between handing out money and the early signs of the disease.

For their study, they took 67 adults close to 70 years old and paired each of them with someone they had never met before; they were then given $10 and asked to split it between themselves.

Participants who more easily gave their money away were found to have a weaker brain state, meaning they were more likely to contract Alzheimer’s.

The results were published in the Journal of Alzheimer’s Disease.

A changing sense of humor

If you’re a recent fan of slapstick comedy, you might also be at risk of Alzheimer’s.

University College London conducted a study in which they surveyed 48 friends and family of both those with Alzheimer’s and frontotemporal dementia about what type of comedy their loved ones preferred, with the options of slapstick comedy, satirical comedy or absurdist comedy.

They were also asked whether their comedy preference had changed within the last 15 years.

The results, published in the Journal of Alzheimer’s Disease, found preferring slapstick comedy started nine years before more common symptoms of dementia.

Meanwhile, another recent study showed that people with early-onset dementia often don’t find other people’s jokes funny, while other research has shown that those with dementia are slow to pick up on sarcasm.

Losing their filter 

As a patient’s brain changes, they may slowly lose their ability to evaluate both what they say and how they act. That’s because the part of the brain that controls our internal filter, the frontal prefrontal cortex, is known to shrink with age, according to experts. 

“These situations can be very confusing, distressing, shocking or frustrating for someone with dementia, as well as for those close to them,” the Alzheimer’s Society has explained. “The person with dementia may not understand why their behavior is considered inappropriate. It’s very unlikely that they are being inappropriate on purpose.”

Some of these situations include patients who are accidentally rude or impolite — and, in some unfortunate cases, inappropriately touching others.

Swearing may also be a marker, as the illness weakens their inhibitions.

A study published in Cognitive and Behavioral Neurology asked 70 patients to name as many words as possible that began with the letters “f,” “a” and “s” in under a minute.

Despite the lack of raw data, 32 patients with dementia offered the swear word “f–k” when asked for a list of words starting with that letter.

A new wardrobe

The disease can make it difficult to get dressed in the morning.

When left unattended, people with Alzheimer’s can pick clothes that don’t go well together and might not be weather appropriate.

Research published in Sociology of Health and Illness studied 38 people in care homes. One study participant, Melissa, discussed the change in her father’s dressing habits after he developed Alzheimer’s.

“I’ve never seen my dad scruffy. Never. Until that day I turned up in the home and he’s sitting there in screwed up clothes which really hurt me because I’m not used to that – not at all,” she said.

Bad Parking 

Decreased driving skills, especially seen in parking, can be an early sign.

A study published in Alzheimer’s Research and Therapy found that those diagnosed with early Alzheimer’s were more likely to drive slower and experience more stark changes in their typical driving habits.

The study was successful enough to create a model based solely on driving habits to predict if people had Alzheimer’s and found to accurately diagnose in 90% of cases.