The specific acoustics of a baby's cry can point to health problems and even indicate the risk of sudden infant death syndrome (SIDS), a scientist said today.

Studies have shown the cry of an infant can suggest medical risk. They might cry at a higher and more variable frequency than normal, but at lower amplitude, and with short utterances. The signals can point to respiratory problems or increased tension and instability of neural control of the vocal tract.

"The cry signal has enormous potential diagnostic value; for example, very high pitched cries can tell us that something may be wrong with the infant, so the cry signal can be an early warning that leads to further neurological testing," said Linda LaGasse of Brown Medical School.

"At-risk infants have undetected neurological damage and that cry analysis may be able to identify these infants when no other symptoms are present," said co-author Barry Lester, also of Brown.

The researchers report their conclusions in the current issue of the journal Mental Retardation and Developmental Disabilities.

Other signals, such as high resonance, can mark infants at risk for SIDS. Resonance is a quality of richness and depth that makes a note from a piano sound different from the same note on a guitar. Noisy, broken-sounding cries can be a similar indicator.

Cry diagnoses are best left to professionals, however.

"Resonance is identified by a computerized analysis of the cry signal," LaGasse said. "A detailed analysis of the cry signal is an important part of understanding the 'full message' of the cry."

But parents should pay attention, too.

"Parents can usually tell the difference between pain and non-pain cries which guides the urgency of their care taking, and helps parents deal with infants with colic," LaGasse said.

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