Cry Analyzer Could Indicate Babies' Health

From soft, coo-like whimpers to heartbreaking sobs, a baby's cries can evoke strong emotions, and yet the reasons for crying can remain mysterious. But now, a new tool for analyzing the sound of a baby's cry could provide clues to crying patterns that might signal health problems.

The cry analyzer, developed by researchers at Brown University, can perceive slight variations in cries that a human ear can't detect. These variations could be used to identify neurological problems or developmental disorders, the researchers say.

"The cry might tell you something you might not otherwise pick up," said psychiatrist Barry Lester of Brown University, part of the team that developed the cry analyzer.

The cry analyzer consists of a standard digital voice recorder for capturing crying sounds, and a computer program that analyzes the sounds and extracts a suite of information about their acoustic features. The system breaks down the cries into 10-millisecond blocks, and measures the pitch, or fundamental frequency — the rate at which the vocal cords vibrate. The average fundamental frequency for a typical baby is about 300 to 400 Hertz, Lester said.

Two cries can have the same fundamental frequency, but still sound different because of differences in the shape and tension of the vocal tract. The brain modifies vocal tract tension via the cranial nerves. "Since the cry is controlled by cranial nerves, now we have a connection between the cry and the brain,"