Babies’ cries linked to their neurological and medical status

Leading researchers in colic and infant development say that a simple analysis of babies’ cries can provide a window into their neurological and medical status.

In a research review in the current issue of Mental Retardation and Developmental Disabilities, Linda LaGasse, PhD, and Barry Lester, PhD, with the Bradley Hasbro Children’s Research Center (BHCRC) and Brown Medical School looked at previous studies that analyzed the acoustics of a baby’s cry. The authors cite the characteristics of a cry that can indicate problems in a baby’s nervous system, as well as sudden infant death syndrome (SIDS). In addition, they cite the importance of how parents react to their squalling offspring.

“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,” says LaGasse.

Overall, studies have repeatedly shown that infants at medical risk (like premature babies), and infants who have been exposed to lead or drugs, cry at a higher and more variable frequency than normal, but at lower amplitude, and with short utterances. These types of cry signals point toward a capacity problem in the respiratory system as well as an increased tension and instability of neural control of the vocal tract.

“Given the results of earlier studies relating cry characteristics to known neurological compromise, these findings suggest that at-risk infants have undetected neurological damage and that cry analysis may be able to identify these infants when no other symptoms are present,” says Lester.

In looking at cry analyses on sudden infant death syndrome, researchers found that high resonance and changes in the cry mode were consistent markers associated with SIDS. Resonance is the characteristic of a sound’s richness and depth that help humans distinguish a C note on a piano versus a guitar, and mode changes are noisy, broken-sounding cries that indicate poor neural control of the vocal track.

While someone might be able to point out a noisy cry, there is little evidence that a high resonance is distinguishable from a low resonance by an untrained listener.

“Instead, resonance is identified by a computerized analysis of the cry signal in the studies cited in the paper — this is why a detailed analysis of the cry signal is an important part of understanding the ‘full message’ of the cry,” says LaGasse.

The authors also note that parents tend to understand the nature of their babies’ cries well, and stress the importance of parental reaction to cries.

“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,” says LaGasse.

But parent perception of their infant’s cry may be affected by conditions such as depression or age of parent which can lead to action or nonaction which may be out of sync with the infant’s needs. The most extreme case is “shaken baby syndrome” where the cry triggers aggression rather than concern in the caretaker.

Lester and LaGasse say that clinicians should be aware of how parents respond (or don’t respond) to their baby’s crying, especially in light of the high prevalence of depression in young mothers.

“Helping parents to correctly interpret their infants’ cries can optimize development particularly in high risk infants who may have atypical signals or high risk parents who may misperceive a normal cry,” they write.

Colicky Babies And Postpartum Depression

A compelling connection exists between colicky babies and postpartum depression, according to a study conducted by a Brown Medical School professor and Rhode Island Department of Health family health experts.

The study is the first to establish a link between colic and depression using a large sample of demographically diverse women. Results will be presented in May at the Pediatric Academic Societies’ 2006 Annual Meeting in San Francisco. The meeting is the largest academic pediatric gathering in the world.

Pamela High, M.D., served as lead. High is a clinical professor of pediatrics at Brown Medical School and director of developmental-behavioral pediatrics at Hasbro Children’s Hospital. She is also head of the Infant Behavior, Cry and Sleep Program run by the Brown Center for the Study of Children at Risk, which is supported by Women & Infants Hospital of Rhode Island.

The research team also included staff from the Rhode Island Department of Health’s Division of Family Health, who provided data and analytical support. They are Hannah Kim, senior epidemiologist; Samara Viner-Brown, chief of data and evaluation and director of the Pregnancy Risk Assessment Monitoring System, or PRAMS; and Rachel Cain, PRAMS coordinator.

High warned that the work does not show a direct cause-and-effect relationship between a fussy baby and a depressed mom. “We can’t say that inconsolability causes depression or that depression causes inconsolability,” High said. “However, we did find a link between the two. And this won’t surprise anyone who knows a mother coping with a fussy baby.”

High directs the Infant Behavior, Cry and Sleep Program – known locally as the Colic Clinic – in Providence. High and other Colic Clinic staff have helped hundreds of families having trouble with their infants’ crying. After conducting an exam and taking a medical history, clinic staffers help new mothers and fathers console their babies, pinpoint the cause of the crying, and take care of their own needs.

A 2005 Brown Medical School study of 93 mothers seen at the Colic Clinic showed that 45 percent reported moderate to severe depressive symptoms. Barry Lester, head of the Brown Center for the Study of Children at Risk, led the study.

“At the clinic, it is not unusual to see mothers who are very tired and sometimes very anxious and depressed,” High said. “Moms are trying hard to understand their child’s needs and meet those needs. Sometimes they feel inadequate when they can’t console their baby.”

The study is based on responses to the Rhode Island PRAMS, an ongoing, confidential survey of women who have recently given birth. The state is one of 32 participating in PRAMS, which is funded by the federal Centers for Disease Control and Prevention and aims to improve the health of new mothers and their babies. Each month, women are randomly chosen to receive the survey, which covers topics such as prenatal care, smoking, and nutrition and breast-feeding.

High is a member of the Rhode Island PRAMS steering committee. The committee was able to choose a few state-specific questions that would be added to the standard survey. The survey already asked about depression. Wondering if there was a connection to colic, High suggested another: “How inconsolable is your baby?”

The new question appeared on Rhode Island’s first PRAMS survey, administered in 2002, and again in 2003. A total of 4,214 new mothers got the questionnaire and 2,927 responded. The majority of mothers were white, married, had household incomes of more than $40,000 per year and had health insurance. Most of their babies were between two and four months of age.

The results: 19 percent of mothers reported moderate to severe symptoms of postpartum depression, and 8 percent reported that their babies were difficult to console. Responses showed a strong connection between the two. Mothers reporting depression were more than twice as likely to report infant inconsolability, and women with inconsolable babies were more than two times as likely to report depression. Even when other variables were controlled – such as age, race and income – the two were closely related.

“Depression and inconsolability are strong predictors of one another,” High said. “One in three women with fussy infants acknowledged that they were depressed.”

Researchers say the study sends a clear message to pediatricians: If you are treating a colicky baby, check on the moms, too. Ask them how they are feeling and if they have support from family and friends. When appropriate, refer women to mental health providers.

“This study is a terrific example of the use of survey data to further our understanding of maternal and child health issues and develop recommendations for improving public health practices,” Viner-Brown said. “It also shows the benefits of partnerships between state governments, universities and hospitals.”