Preterm babies are born before the 37th week of pregnancy. They are at high risk for neurological and developmental consequences that can continue to have effects into childhood. Poor motor development is a common result. Postural control is the infant’s ability to maintain the body’s center of mass over a stable or moving base of support, making it the foundation for motor development. This ability requires sufficient control of the head and neck, and develops quickly during the infant’s first year of life. Development of postural control is assessed by pulling an infant by their arms or hands, from a position of lying on their backs, to a sitting position. Physicians hypothesize that head lag in newborns is a marker of poor neurobehavior because it suggests complications in motor development.
Physicians hypothesize that head lag in newborns is a marker of poor neurobehavior because it suggests complications in motor development.
A typical infant response during pull-to-sit is for the head to remain in line with the shoulders. On the other hand, head lag is when the head is not righted and falls behind the shoulders. There is a greater incidence of head lag in preterm babies and it may be an important predictor of developmental outcome.
In a longitudinal study at St. Louis Children’s Hospital, Dr. Roberta Pineda and colleagues investigated the progression of head lag in preterm infants during neonatal intensive care unit (NICU) hospitalization, identified the medical factors that may contribute to head lag, and examined the relationship between head lag and neurodevelopmental outcome. Neurodevelopmental outcomes may include motor and neurologic function, visual-motor integration skills, IQ, academic achievement, language, attention-deficit hyperactivity disorder (ADD) and behavioral issues.1
Participants of this study included babies born 30 weeks or earlier who were enrolled in the study within the first 72 hours of life. Head lag was assessed at 30 and 34 weeks postmenstrual age,which encompasses the number of weeks of pregnancy plus the baby’s actual age, using the Premie-Neuro.2 The Premie-Neuro exam consists of 3 subscales: Neurologic, Movement, and Responsiveness. Each of these categories consist of 8 items and assesses skills such as arm recoil, yawn, leg movements, responsiveness, and head lag, just to name a few.
Head lag was also assessed at term equivalent age (the baby’s age had they not been born premature) using the Dubowitz Neurological Examination.3 This exam is very similar to the Premie-Neuro exam, but it is used to neurologically evaluate full-term newborns. This test has 34 items compared to the 24 items of the Premie-Neuro exam, and has 6 subcategories of tone, tone patterns, reflexes, movements, abnormal signs, and behaviors, compared to the 3 subscales previously mentioned for the Premie-Neuro.
For both assessments, scoring for head lag was determined as follows: 0= head drops and stays back, 1= tries to lift head but drops it back, 2= able to lift head slightly, 3= lifts head in line with body, and 4= head in front of body. In this study, scores were dichotomized in order to investigate the associations between head lag and medical conditions, environmental exposures, and neurobehavioral outcome: scores of 0 and 1 indicated significant head lag, while a 2, 3, or 4 indicated no head lag.
At term-equivalent age, the NICU Network Neurobehavioral Scale was used to assess neurobehavior. At two years old, parents completed the Modified Checklist for Autism in Toddlers to determine autism risk, and the Infant-Toddler Social and Emotional Assessment, to determine social-emotional development. The Bayley Scales of Infant and Toddler Development also tested neurodevelopment. Results of these assessments were investigated in their association with head lag.
It was found that 38% of infants 30 weeks PMA and 33% of infants 34 weeks PMA were too unstable to assess head lag. However, of the infants that could be tested, 90% exhibited head lag at 30 weeks PMA, 60.5% at 34 weeks PMA, and 57.8% at term-equivalent age. More head lag was seen in infants who stayed longer in the NICU, had more days of endotracheal intubation (a tube is placed into the windpipe through the nose or mouth to keep an open airway), and sepsis (a life-threatening inflammatory response to an infection). At term-equivalent age, significant associations were found among head lag, medical, and environmental factors. At this age, head lag was also related to cerebral injury and alterations in neurobehavior, including low muscle tone, poor quality of movements, asymmetry, poor self-regulation, and poor reflex development. Contrary to term-equivalent age, there were no associations found between head lag, autism risk, and social-emotional outcome at two years old. Furthermore, there were no associations between head lag and language, cognitive, or motor scores determined from the Bayley Scales, and no head lag or developmental delays were found in the two-year-old infants. The Bayley-III is a widespread, norm-referenced neurodevelopmental assessment for children 1-42 months old. It is considered “the gold standard” in developmental evaluation. Composite scores less than 70 for for language, cognitive, and motor subscales indicate developmental delay and were investigated for associations with head lag. In this study, none were found.
At term-equivalent age, significant associations were found among head lag, medical, and environmental factors.
Given that the incidence of head lag changed before and at term-equivalent age, head lag may not be a stable marker immediately before and after birth. Muscle development may be responsible for the decrease in head lag as infants get older. The point at which head lag should be present during infancy remains a topic of debate. In addition, the relationship between head lag and immaturity, as well as other medical factors like intubation and sepsis, support the hypothesis that head lag may be an important marker of current developmental status and wellness.
In addition, the relationship between head lag and immaturity, as well as other medical factors like intubation and sepsis, support the hypothesis that head lag may be an important marker of current developmental status and wellness.
From this study, it was determined that head lag at term-equivalent age may not be a good marker for long-term outcomes. However, this result may be due to the fact that investigating one isolated neonatal response is not perceptive enough to discriminate typical from atypical outcome, and therefore, predict future consequences. Future research is needed to determine early markers for developmental outcome. Nevertheless, head lag can provide healthcare professionals with clinical information that can support the use of early therapeutic interventions intended to optimize outcomes.
Pineda R. G., Reynolds, L.C., Seefeldt, K., Hilton, C.L., Rogers, C.E., & Inder, T.E. (2015)Head Lag in Infancy: What Is It Telling Us? The American Journal of Occupational Therapy. January/February 2016. 7(1):1-8.
Other Information Gathered From
Aylward G.P. et al. Neurodevelopmental outcomes of infants born prematurely. Journal of Developmental & Behavioral Pediatrics. December 2005. 26(6): 427-440.
Gagnon K. et al. The Premie-Neuro. Advances in Neotonal Care. 2012. 12(5): 310-317.
Dubowitz L. et al. The Dubowitz Neurological Examination of The Full-Term Newborn. Medical Retardation and Developmental Disabilities Research Reviews. 2005. 11: 52-60.