Strange table manners could be more than just quirks, they may be an early sign of dementia, experts have warned. 

Frontotemporal dementia, which affects actor Bruce Willis and around 60,000 other Americans, results from the progressive deterioration of brain regions associated with personality and language skills.

Symptoms to watch for include changes in personality and behavior, like acting impulsively or showing a lack of empathy, as well as language challenges, where individuals struggle to find the right words.

However, experts highlight that a lesser-known symptom of this condition is “obsessive and repetitive behaviors,” which can also influence a patient’s diet and eating habits.

Patients may become fixated on one food, refusing to eat anything else, researchers in DC said previously in a study. They may also eat non-food objects or steal from other people’s plates.

Dr Marilena Aiello, a neuroscientist who researches the condition, said previously: ‘These behaviors are problematic, of course, socially, but also with regard to patients’ health as they tend to gain weight.

‘[But], some people lose weight because they eat a narrow range of foods in an obsessive way.’

It was not clear why the condition may cause this behavior, but researchers say it is potentially linked to alterations in the body’s signals for hunger and fullness.

Bruce Willis, pictured above with wife Emma Heming in July 2018, suffers from frontotemporal dementia

It is not known whether Bruce Willis suffers from any compulsive eating behaviors as a result of his condition, but his family has said he is struggling with communication.

And earlier this month, his wife Emma Heming Willis revealed the subtle sign she noticed shortly before his diagnosis.

She told ABC News: ‘For someone who is really talkative, very engaged, he was just a little more quiet, and when the family would get together he would kind of just melt a little bit.’

He also soon began losing words, she said, and a stutter he dealt with as a child returned.

‘[He] felt very removed, a little cold, not like Bruce, who is very warm and affectionate. 

‘Going the complete opposite of that was alarming and scary,’ she added.

In frontotemporal dementia, behavioral changes are normally the first noticeable sign of the disease. In Alzheimer’s, for comparison, which affects up to 6.7 million people,  the first signs are normally memory loss or confusion with time or place.

Over time, more areas of the brain degenerate, meaning patients with frontotemporal dementia often eventually mirror those with late-stage Alzheimer’s.

Experts say that people suffering from the condition may have compulsive eating behaviors (stock image)

Other symptoms of frontotemporal dementia include difficulty eating or swallowing, trouble walking and vulnerability to infections.

The condition is not normally fatal on its own, but weakens the body and raises the risk of life-threatening infections or other complications. This may include problems swallowing or eating and drinking.

There is no cure for the disease, although some drugs and therapies may help to slow the progression of the symptoms.

It is also not clear what causes frontotemporal dementia, although it has previously been linked to a build-up of protein clumps in the brain.

Some researchers say it can also be caused by damage to blood vessels in the brain, which they say can affect the supply of nutrients and oxygen to brain cells.