Acoustic quality of cry in very-low-birth-weight infants at the age of 1 1/2 years

Abstract 

Background

Infant cry characteristics reflect the integrity of the central nervous system. Previous studies have shown that preterm infants and infants with neurological conditions have different cry characteristics such as fundamental frequency compared to healthy full-term infants. Cry characteristics of preterm infants after the first year of life have not been studied.

Aims

The aim of this study was to assess the quality of cry in 1 1/2-year-old very-low-birth-weight infants (VLBWI, ≤1500 g at birth).

Study subjects and design

Study groups included 21 VLBWI and 25 healthy full-term controls. Thirty seconds of pain cry after vaccination was recorded at well-baby clinics. The first cry utterance was acoustically analyzed using Praat software. The quality of cry was compared between the groups. In addition, the association of cry quality to patient characteristics, to developmental outcome, and to findings in brain imaging studies of the VLBWI was studied.

Results

The cry response was elicited in 20 of the 21 VLBWI and in 20 out of 25 full-term infants. VLBWI had higher minimum fundamental frequency and fourth formant values. Patient characteristics that were associated with cry quality were 5-min Apgar scores, the occurrence of bronchopulmonary dysplasia, Bayley Psychomotor Index scores at 12 months, and current weight and head circumference.

Conclusions

Differences found between the study groups were not explained primarily by brain pathology or by patient characteristics, so it seems that prematurity has an impact on cry quality still at the age of 1 1/2 years.

Keywords: VLBW infant, Premature infant, Cry, Acoustic analysis, Cry quality, Brain injury, Behaviour