Brain scans can be used to accurately predict a person's age, scientists claim.

While people are often able to pass for ages much older or younger than their actual years, scientists found that the brain tells all.

Scientists are now able to tell with 92 percent accuracy how old a person is just by looking at magnetic resonance images (MRI) of his or her brain.

The latest discovery of the brain's 'developmental clock' gives scientists new insight into how the human brain changes over time and may have deeper implications for both neuroscience and medicine.

"We have uncovered a 'developmental clock' of sorts within the brain -- a biological signature of maturation that captures age differences quite well, regardless of other kinds of differences that exist across individuals," researcher Timothy Brown of the University of California, San Diego School of Medicine said in a statement.

Brown and his team scanned the brains of 885 people ranging in age from 3 to 20 and identified 231 biomarkers of brain anatomy that when combined could reveal a person's age with more than 92 percent accuracy, a precision rate that surpasses any other age-determining biological measure.  

While previous researchers have already examined some of the same brain biomarkers individually, Brown explained that the key was finding a way to combine them all to understand the multidimensional nature of brain structure and characteristic patterns of developmental change with age.

Researchers explained that as the brain develops with age, different features mature at different rates, and while other scientists have monitored these individual features, like cortex thickness and the size of different brain regions, it had been difficult to determine developmental timing because individuals vary widely in the growth and sizes of many brain regions.

Researchers believe that this new approach of studying the brain as a whole has potential for clinical use in abnormal brain development, allowing doctors in the future to spot developmental problems like autism and ADHD earlier in life.

"The fact that we found a collection of brain measures that so accurately captures a person's chronological age means that brain development, or at least certain anatomical aspects of it, is more tightly controlled than we knew previously," Brown said.

"The regularity in this maturity metric among typically developing children suggests that it might be sensitive to detecting abnormality as well," he added.

The new model allows researchers to simultaneously compare different brain features and their development and determine which brain features are changing the most at a given age, allowing scientists to correctly guess a person's birthday to within a year on average.

Researchers are unsure about whether these anatomical changes in the brain will relate to maturity in terms of human behavior, which isn't always reflected by a person's age.

"The anatomy and physiology of these dynamic, interacting neural systems, which we can probe in different ways with MRI scans, have to account for the changes we all observe in human psychological development," Brown said. "We're still figuring out exactly how."

The study was published in Current Biology.