Most of us have two voice changes in our lifetime: first during puberty, as the vocal cords thicken and the voice box migrates down the throat. Then a second time as aging causes structural changes that may weaken the voice.
But for some of us, there's another voice shift, when a disease begins or when our mental health declines.
This is why more doctors are looking into voice as a biomarker – something that tells you that a disease is present.
Vital signs like blood pressure or heart rate "can give a general idea of how sick we are. But they're not specific to certain diseases," says Yael Bensoussan, MD, director of the University of South Florida's Health Voice Center and the co-principal investigator for the National Institutes of Health's Voice as a Biomarker of Health project.
"We're learning that there are patterns" in voice changes that can indicate a range of conditions, including diseases of the nervous system and mental illnesses, she says.
Speaking is complicated, involving everything from the lungs and voice box to the mouth and brain. "A breakdown in any of those parts can affect the voice," says Maria Powell, PhD, an assistant professor of otolaryngology (the study of diseases of the ear and throat) at Vanderbilt University in Nashville, who is working on the NIH project.