Change in key facial muscle could help identify dementia risk 6 years before diagnosis – are you at risk?

A CHANGE in a muscle located in the head may be a warning sign of Alzheimer's disease, according to researchers.

But they also suggested what may help prevent the onset of the most common type of dementia.

A new study carried out by American scientists has suggested a decrease in the temporalis muscle - one of the muscles used for moving the lower jaw and doing things like chewing - could be one of the first signs of Alzheimer's disease.

The research team explained skeletal muscles make up about one-third of a person's total body mass.

Muscles are connected to the bones and allow for a wide range of movements.

But as people grow older, they begin to lose skeletal muscle mass.

Because age-related skeletal muscle loss is often seen in older adults with Alzheimer's disease dementia, the research team aimed to examine whether temporalis muscle loss - a measure of skeletal muscle loss - is associated with an increased risk of Alzheimer's dementia in older adults.

Previous studies have shown temporalis muscle thickness and area can be an indicator of muscle loss throughout the body.

Study lead author Dr Kamyar Moradi, of Johns Hopkins University School of Medicine in Baltimore, said: "Measuring temporalis muscle size as a potential indicator for generalised skeletal muscle status offers an opportunity for skeletal muscle quantification without additional cost or burden in older adults who already have brain MRIs for any neurological condition, such as mild dementia.

"This is the first longitudinal study to demonstrate that skeletal muscle loss may contribute to the development of dementia."

How the study was carried out

Dr Moradi used brain MRI exams to quantify skeletal muscle loss in 621 participants, with an average age of 77 and who didn't dementia.

The researchers manually segmented the bilateral temporalis muscle on MRI images and calculated the sum cross-sectional area (CSA) of those muscles.

Participants were categorised into two distinct groups: large CSA (131 participants) and small CSA (488 participants).

Based on their analysis, a smaller temporalis CSA was associated with a higher incidence risk of dementia.

A smaller temporalis CSA was also associated with a greater decrease in memory composite score, functional activity questionnaire score and structural brain volumes over the average follow-up period of 5.8 years.

Study co-senior author Professor Marilyn Albert said: "We found that older adults with smaller skeletal muscles are about 60 per cent more likely to develop dementia when adjusted for other known risk factors."

But she said early detection through readily available brain MRI could enable "timely interventions" to address skeletal muscle loss - such as physical activity, resistance training and nutritional support.

Study co-senior author Professor Shadpour Demehri added: "These interventions may help prevent or slow down muscle loss and subsequently reduce the risk of cognitive decline and dementia."

The findings were presented at the annual meeting of the Radiological Society of North America (RSNA) in Chicago.

Other ways to prevent Alzheimer's disease...

A large study published in the journal BMJ Medicine last year suggested high levels of lean muscle might protect against Alzheimer's disease.

The Alzheimer's Society also recommends some simple lifestyle changes to reduce your risk.

Do regular physical exercise - this is considered one of the best ways to reduce your risk of dementia as it's good for your heart, circulation, weight and mental well being.

Drink less alcohol - drinking too much alcohol at one time can expose the brain to high levels of harmful chemicals.

Don't smoke - smoking can harm the circulation of blood around the body, particularly the blood vessels in the brain, as well as the heart and lungs.

Stay mentally well - social isolation can greatly increase a person’s risk of dementia, so engaging in social activities may help.

Manage long-term conditions - high blood pressure, high cholesterol and diabetes can increase your risk of dementia. An important way to manage these is to get regular health checks.

Protect your eyesight and hearing - uncorrected vision loss can increase a person's risk of dementia. Hearing loss is also related to an increased risk, but using hearing aids could help.