May 14 (HealthDay News) -- What's in a word? Emotion, especially if it's said with inflection.

Now, Swiss scientists report that they can detect a person's sense of the emotion behind a word by "reading" the brain as it processes sounds from the world around it.

The findings could lead to better understanding of mental illnesses that affect how people interpret the emotions of others, such as autism and schizophrenia, said study co-author Patrik Vuilleumier, a researcher at University Hospital of Geneva.

The researchers scanned the brains of 22 subjects -- 13 women, nine men -- as they listened to the voices of actors saying a "pseudosentence," which is a sentence of words that sound real but are actually made up.

The actors spoke the words in five ways -- with sadness, anger, joy, relief or a neutral tone. Using functional MRIs, the researchers tried to see if they could determine what emotion the subjects heard by looking at the reactions of their brains.

The findings appear in the May 14 online issue of Current Biology.

The researchers discovered that each emotion left a different "signature" in the part of the brain that handles the processing of sound.

"This should give insights into the way emotions are coded in the brain, but also tools to assess how different people experience events in different conditions," Vuilleumier said.

The research suggests that the brain considers emotion early on, as it processes sound, said Duke University neuroscientist Scott Huettel, who's familiar with the findings.

It's not clear whether the brain works the same way when it tries to understand emotion in written words, such as those in e-mails or text messages. "For the vast majority of people [in history], emotion as conveyed in written words is pretty modern," Huettel said. "You can think of how recently literacy has taken hold."

In the future, research like this could help scientists get a better handle on psychiatric disorders that affect how people perceive the world around them, Huettel said.

Autistics, for instance, "don't have a good sense of what other people are thinking, doing or feeling," he said. This research, he said, could allow scientists to better understand exactly what goes wrong in their brains.

The knowledge may not lead directly to a treatment, he said, but could provide "a way to think about a disorder."

SOURCES: Patrik Vuilleumier, researcher, University Hospital, Geneva; Scott Huettel, Ph.D., associate professor, psychiatry and neuroscience, Duke University, Durham, N.C.; May 14, 2009, Current Biology, online