Cry features reflect pain intensity in term newborns: an alarm threshold.
The purpose of this study was to assess differences in sound spectra of crying of term newborns in relation to different pain levels. Fifty-seven consecutively born neonates were evaluated during heel-prick performed with different analgesic techniques. Crying was recorded and frequency spectrograms analyzed. A pain score on the DAN (Douleur Aiguë du Nouveau-né) scale was assigned to each baby after the sampling. Three features were considered and correlated with the corresponding DAN scores: 1) whole spectral form; 2) the fundamental frequency of the first cry emitted (F0); and 3) root mean square sound pressure normalized to its maximum. After emission of the first cry, babies with DAN scores >8, but not with DAN scores < or =8 (p < 0.001), showed a pattern ("siren cry") characterized by a sequence of almost identical cries with a period on the order of 1 s. A statistically significant correlation was found between root mean square (r2 = 89%, p < 0.01), F0 (r2 = 32%, p < 0.05), siren cry (r2 = 68.2%, p = 0.02), and DAN score. F0 did not show significant correlation with DAN score in the subset of neonates with DAN scores < or =8 (r2 = 1.4%, p = 0.94), and babies with a DAN score >8 had a significantly higher F0 than those with lower DAN scores (p = 0.016). An alarm threshold exists between high (>8) and low (< or =8) DAN scores: crying has different features in these two groups. When pain exceeds a DAN score of 8, usually a first cry at a high pitch is emitted, followed by the siren cry, with a sound level maintained near its maximum.
Bellieni
Carlo V
CV
Department of Pediatrics, University of Siena, Siena, Italy. bellieni@iol.it
Sisto
Renata
R
Cordelli
Duccio M
DM
Buonocore
Giuseppe
G
D015331:Cohort Studies; D003448:Crying; D005149:Facial Expression; D006801:Humans; D007231:Infant, Newborn; D010146:Pain / Q000175:diagnosis*; D010147:Pain Measurement / Q000379:methods*; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography