The properties of V̂ in newborns across repeated measures

✍ Scribed by Robert E. Arendt; Leslie F. Halpern; William E. MaClean Jr.; Grant A. Youngquist

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 780 KB
• Volume: 24
• Category: Article
• ISSN: 0012-1630
• DOI: 10.1002/dev.420240203

✦ Synopsis

Abstract

It has been argued that a recently developed measure, vagal tone (V̂), is a significant advancement over other existing methods of assessing the periodic variation in heart rate associated with respiration (respiratory sinus arrhythmia). It has been further suggested that, as a noninvasive measure of vagal nerve efferent activity, V̂ may facilitate the early identification of infants at risk for developmental disabilities. This study addressed the relationship between V̂ and other measures of cardiac activity and behaviroal state and the stability of V̂ across repeated measures. Twelve samples of cardiac activity were collected from each of 20 full term infants, 6 samples on each of two consecutive days. V̂ values were derived using a spectral analysis program comparable to Porges' patented MXedit process. Measures of behavioral states were collected by continuous observation. Heart period and heart period variability were highly correlated with V̂. Variation in V̂ between behavioral states was also detected. Repeated assessments revealed that average V̂ values collected in the same state were not significantly correlated across successive days. This short‐term variability both between and within individuals does not support the notion that a single assessment of V̂ can, by itself, be used to identify at‐risk infants or predict developmental outcome.