Newborn infants' cry after heel-prick: analysis with sound spectrogram

Area of Science:

• Neonatal care
• Pain assessment
• Infant cry analysis

Background:

• Newborn infants experience pain, necessitating reliable assessment methods.
• Infant crying is a primary communication signal, often indicating distress or pain.
• Objective measures for pain in neonates are crucial for appropriate clinical management.

Purpose of the Study:

• To investigate the potential of using newborn infant cry characteristics to measure pain.
• To analyze acoustic properties of cries following a painful stimulus.
• To determine if specific cry features correlate with pain intensity or duration.

Main Methods:

• Prospective, descriptive study involving 50 healthy newborn infants.
• Heel-prick stimulus administered for phenylketonuria screening.
• Recording and spectrographic analysis of cry sounds, including duration, fundamental frequency, and melody.

Main Results:

• Cries following the heel-prick stimulus exhibited significantly higher fundamental frequencies and longer durations in the initial cries compared to later ones.
• The acoustic properties of the first cry differed significantly from the fifth cry, suggesting a change in the nature of crying.
• Substantial inter-infant variability was observed in cry duration, total crying time, and fundamental frequencies.

Conclusions:

• Newborn infants demonstrate recognizable physiological responses to pain through their cries.
• Cry analysis shows potential for pain assessment, but acoustic features can be influenced by various stimuli.
• Accurate pain measurement using infant cries is feasible only when the specific cause of crying is identified.