Newborn acoustic cry characteristics of infants subsequently dying of sudden infant death syndrome.

OBJECTIVE

To test the hypothesis that the occurrence of a neonatal cry exhibiting a high first formant is a risk factor for sudden infant death syndrome (SIDS) and to evaluate the association between SIDS and other acoustic cry variables.

METHOD

We recorded cries and obtained medical and demographic data for 21,880 apparently healthy term newborns. Two cries were recorded between days 2 and 7 of life, after a painful stimulus at the time of routine blood drawing. Acoustic variables were measured with an automated computer-based analysis system. Twelve infants died of SIDS. Age at death ranged from 19 days to 6.5 months. Autopsies were performed in all cases. At least one cry was analyzed for all 12 infants who died of SIDS and 20,167 infants without SIDS. Two cries were analyzed for 9 infants who died of SIDS and 14,235 infants without SIDS.

RESULTS

Newborns whose first cries exhibited a high first formant were more likely to die of SIDS than infants whose first cries did not have this characteristic (relative risk, 3.5; 95% confidence interval [CI], 1.1 to 12). The relative risk for SIDS increased to 8.8 (95% CI, 2.2 to 35) for newborns whose second cries showed that this characteristic persisted. Newborns with the combination of both a high first formant and a high number of mode changes on both of two cries had a relative risk of 32 (95% CI, 8.7 to 120).

CONCLUSIONS

We have shown an association between alterations in neonatal cry acoustics and SIDS. Cry analysis represents a potentially important research tool that, when studied in relation to other physiologic measures, may lead to an improved understanding of SIDS.