Plagiocephaly and Developmental Disorders: Investigating the Clinical Link

Abstract

Nonsynostotic plagiocephaly (NSP), also known as deformational plagiocephaly, is an infant cranial asymmetry caused by external pressures and not by premature suture closure. Its prevalence has risen over the past few decades, probably because of supine sleeping recommendations to avoid sudden infant death syndrome (SIDS). Although NSP was previously viewed as a strictly cosmetic condition, new evidence proposes a possible connection between NSP and neurodevelopmental disorders such as cognitive, motor, and language development delay. This review discusses the present knowledge regarding NSP, its possible association with developmental disorders, risk factors, and clinical management implications. Early identification and treatment could potentially prevent some of the developmental issues related to NSP, making parental education and interprofessional care necessary.

Introduction

Nonsynostotic plagiocephaly (NSP) refers to an asymmetrical head shape in infants due to external pressures, not craniosynostosis, which is the early closing of cranial sutures. The incidence of NSP has risen in the last few decades due mainly to the "Back to Sleep" campaign promoting sleeping in the supine position to prevent SIDS. Although NSP is generally considered to be a benign and cosmetic condition, there has been some concern about its link with developmental disorders.

Recent research has examined whether NSP is only a marker of underlying neuromuscular disease or if cranial asymmetry itself is responsible for developmental delay. The purpose of this review is to review the prevalence of NSP, its correlation with developmental disorders, risk factors, and possible intervention strategies to maximize outcomes for affected infants.

Incidence and Risk Factors of Nonsynostotic Plagiocephaly

The incidence of NSP is reported to vary, and estimates range between 20% and 50% in children under one year of age. The increase in cases is paralleled by the increase in adherence to safe sleep practices, where infants are put to sleep on their backs. Torticollis, increased time spent in car seats or infant carriers, prematurity, multiple births, and reduced tummy time are other contributing factors.

NSP is more common in firstborn infants because of a relatively limited intrauterine environment, which may result in positional preference after birth. Premature birth is also an important risk factor, as premature babies have softer skulls and tend to spend longer periods in neonatal intensive care units (NICUs) in supine positions.

The Relationship between NSP and Developmental Disorders

Historically, NSP was considered an aesthetic issue without long-term developmental consequences. However, emerging research suggests a correlation between NSP and neurodevelopmental outcomes, including cognitive, motor, and language delays. While the causative nature of this relationship remains debated, several hypotheses have been proposed:

1. Underlying Neuromuscular Weakness: Infants with NSP often exhibit torticollis or muscle imbalances, which could indicate broader neuromuscular immaturity and affect motor development.

2. Restricted Brain Growth: Some researchers suggest that persistent skull asymmetry may exert subtle mechanical effects on brain development, potentially impacting neural connectivity.

3. Environmental and Parental Factors: Infants with NSP may experience altered interactions with caregivers due to positional preferences, affecting sensory-motor and language development.

Increased evidence underlies these correlations. One study indicated that kids with moderate to severe NSP scored lower on language and motor skills tests than their non-NSP counterparts. Another longitudinal study indicated that infants diagnosed with NSP were more likely to receive special education later in childhood. Yet, if NSP causes delays in development or is a sign of pre-existing neurodevelopmental vulnerability, it is unclear.

Neurodevelopmental Domains Affected

Several key neurodevelopmental areas have been implicated in children with NSP:

1. Motor Development: Infants with NSP may exhibit delays in rolling over, sitting up, and crawling, potentially due to underlying muscle asymmetries or restricted head movement.

2. Language and Cognitive Skills: Some studies suggest an association between NSP and delays in receptive and expressive language abilities, possibly linked to reduced sensory exposure and motor interactions.

3. Attention and Behavioral Issues: Preliminary research indicates a potential relationship between NSP and attention-deficit/hyperactivity disorder (ADHD), though further studies are needed to clarify this link.

Clinical Implications and Management Strategies

Given the potential association between NSP and developmental concerns, early identification and intervention are crucial. The following strategies can help mitigate risks and support optimal development in affected infants:

1. Parental Education: Caregivers should be educated on the importance of supervised tummy time, repositioning techniques, and minimizing prolonged supine positioning.

2. Physical Therapy: Infants with significant skull asymmetry and torticollis may benefit from physical therapy to improve neck muscle function and promote symmetrical movement patterns.

3. Helmet Therapy: Cranial orthotic therapy (helmeting) is considered in cases of moderate to severe NSP, typically between 4 to 12 months of age, to help guide skull growth and improve cranial symmetry.

4. Developmental Monitoring: Infants diagnosed with NSP should be monitored for signs of developmental delays, with early referral to speech, occupational, or physical therapy if needed.

Future Research Directions

Although present data indicate an association between NSP and developmental outcomes, additional investigation is necessary to elucidate causality and underlying mechanisms. Longitudinal research following children with NSP through adolescence might be useful in assessing long-term neurodevelopmental consequences. Moreover, the delineation of subgroups of infants at greater risk for developmental difficulty may enable the development of more specific screening and intervention methods.

Conclusion

Nonsynostotic plagiocephaly is an extremely prevalent neonatal condition with strong extrinsic influences, primarily related to sleep position. While once thought to be merely a cosmetic concern, growing evidence implies possible correlations with neurodevelopmental delays. Whether NSP is a direct cause of these delays or only a marker for intrinsic neurodevelopmental susceptibility remains uncertain, but early intervention utilizing repositioning techniques, physical therapy, and neurodevelopmental monitoring can potentially maximize outcomes. With ongoing growth in research here, a multifaceted plan with pediatricians, therapists, and caregivers still is critical to the best developmental course for compromised infants.

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