Deformational Head Shape Deformities: Benign or Serious Problem?
Over the past 7 years, there has been a rise in the number of presentations at cranial facial and orthotic and prosthetic meetings about the escalating incidence of head shape deformities in young babies. Controversy exists as to whether this is a benign cosmetic problem, or a symptom with the potential for serious developmental, cognitive, and sensory ramifications. The purpose of this paper is to report on current research regarding this controversy, and to provide a context for how each skull deformity can impact the infant's ability to process visual, auditory, and sensory input.
Causes of Skull Deformities
A skull deformity in a young baby is defined in this paper as an asymmetry in the shape, cranial vault or height of the baby's skull or a disproportionate relationship of the width to the length of the skull, with accompanying abnormal features. The skull can assume an abnormal shape due to intrinsic factors like prematurely closed sutures (craniosynostosis) and/or genetic or metabolic anomalies including abnormal development of the skull plates and sutures. Babies with congenital anomalies of the cervical spine can also develop plagiocephaly secondary to the faulty alignment of the vertebrae. This paper will not address skull deformities caused by intrinsic factors, but rather will focus on deformities that are the result of extrinsic forces.
Extrinsic factors that contribute to skull deformities are well documented and can begin in the uterus. Congenital causes include torticollis, breech positioning, multiple fetuses, an inadequate amount of amniotic fluid and a difficult or prolonged delivery of the baby.2,3,4,5,6 Most skull deformities resolve in about 6 weeks after birth once the deforming force is removed. But if the baby has torticollis or neck muscle asymmetry that is not corrected, or if the baby is not positioned in a variety of ways to prevent additional flattening, the skull deformity may not resolve. Term and preterm infants may develop abnormal head shapes "due to medical treatment, nursing care practices, positioning limitations and underlying muscle tone abnormalities.7
Cultural parenting practices impact every baby, and along with the Back to Sleep program, daytime positioning affects the shape and symmetry of the skull.3 Parental practices are difficult to change and are strongly influenced by the practices of grandparents. Back to Sleep program advocates such as the SIDS Alliance of Illinois have recently reached out to grandparents with a campaign to reinforce supine sleeping since this generation positioned their own babies prone to sleep. The literature has long verified that sleep position affects the proportion of the width to length ratio of the skull (Cephalic Ratio). Babies who sleep supine develop a wider face and shorter skull than infants who sleep prone or mix their sleeping positions.8 In fact, in North America, most babies who sleep on their backs have a cephalic ratio that is higher than the cephalic ratio of their parents, who were prone sleepers.9 Van vlimmeren and others have found that parenting practices such as bottle feeding only- particularly on one side, and tummy time less than 3x day contributed to deformational plagiocephaly at 7 weeks.10
The American Academy of Pediatrics wrote a position paper on plagiocephaly in 2003, to encourage early identification and to clarify for pediatricians and parents that the "Back to Sleep" program also includes "Tummy to Play". Many parents over-generalize the guidelines and interpret Back to Sleep to mean that back (supine) positioning is good all the time as protection against SIDS.11,3,4 This misconception has contributed to the widespread use and popularity of convenient infant car seats as daytime positioning aids in addition to other holding devices like bouncy seats and swings. The increased use of supine positioning during awake, daytime hours increases the likelihood of more severe skull deformities. 14,15
Review of the Literature
Although there is widespread agreement that there is a cosmetic component to head shape deformities, a number of studies in the last several years raise concerns about medical conditions associated with untreated deformational plagiocephaly.
In 2000, Miller and Clarren conducted a phone interview of the families of 63 infants of school age who had been diagnosed with deformational plagiocephaly. The purpose of the study was to determine if these children required any special services in school including special education, speech, physical or occupational therapy as defined by their individualized education program (IEP). This group of children was compared to the numbers of children referred for special services in the state of Washington each year, and also to the services needed by their siblings. The study found that "children with deformational plagiocephaly comprise a high risk group for developmental difficulties presenting as subtle problems of cerebral dysfunction during the school years". They advised that timely evaluation is indicated to ensure that children in the high risk group are receiving appropriate services based on their underlying special needs.16
Panchal et al. reached similar conclusions in a prior study involving infants with plagiocephaly. The investigators found that before any intervention, infants with plagiocephaly without synostosis demonstrated delays in cognitive and psychomotor development.17 Another study out of University of Washington concluded that children with deformational plagiocephaly should be screened and monitored for developmental delays or deficits.18
Kane et al. found a correlation between uncorrected plagiocephaly (without synostosis) and mandibular dymorphologies. For subjects with plagiocephaly without synostosis, the authors found that various forms of jaw malformations occurred at a statistically significant rate. Although the authors noted that a certain degree of asymmetry may be normal, "the magnitude of the asymmetry" indicated abnormality in jaw morphology in the subjects with plagiocephaly.19
Kordestani et al. showed that before any intervention, infants with deformational plagiocephaly have significant delays in mental and psychomotor development patterns compared to standardized populations. The 110 infants in the sample were scored on the basis of a mental development index using groupings of "accelerated," "normal,' "mild delay" and "severe delay." Notably, none of the infants with plagiocephaly were found to be "accelerated," even though a normal distribution would have expected 16 percent of the sample to be in the accelerated group.20
In 2005, Siatkowski et al. demonstrated that uncorrected plagiocephaly may affect visual field development. A study of 40 infants with deformational posterior plagiocephaly found significantly higher occurrences of constriction of one or more hemifields by at least 20 degrees compared to infants without plagiocephaly.21
No research has been published over the last 10 years to support the hypothesis that deformational plagiocephaly is only a cosmetic issue although this is still a widely held belief.
Impact of Head Shape on Developmental Skill Acquisition
Based on the evidence that deformational plagiocephaly can have visual motor, auditory, bony, and developmental ramifications, it is helpful to consider how each head shape deformity can interfere with normal development. The following section identifies the most common abnormal head shapes caused by extrinsic molding, and proposes possible reasons for the negative impact of the deformity on the baby's development.
Deformational plagiocephaly is an asymmetrical deformity of the head caused by extrinsic factors. In its most severe presentation, there is impressive posterior and anterior asymmetry of the skull accompanied by ear, orbit, cheek, and jaw asymmetry.
Glasgow found a significant association between deformational plagiocephaly and infants who had a preference for holding their heads in one position.22 Clearly, torticollis is often a contributing influence when the baby has moderate to severe plagiocephaly. Cheng reported that babies with congenital muscular torticollis presented with accompanying plagiocephaly 90% of the time,23 and Graham reported that "some associated torticollis was present in all" subjects diagnosed with plagiocephaly in his 2004 study.24 According to Ross, the asymmetrical tonic neck reflex (ATNR) is quite influential in torticollis, and therapeutic efforts must focus on the integration of the ATNR across all positions in order to develop midline head control and skills.25 The interaction between the neck muscle asymmetry and plagiocephaly can limit head and neck movements necessary for skill development.
If the occipital flattening is accompanied by apparent anterior ear shift, consider the effect of that shift on the baby's auditory system that is rapidly analyzing sounds and experiences in the first months of life. Researchers in Helsinki examined auditory ERPs (external response potential) tones in infant patients. They found that babies with plagiocephaly exhibited smaller amplitudes of response than healthy subjects, which "signals compromise of brain functioning". They further concluded that infants with deformational plagiocephaly have an elevated risk of sound processing disorders.26
When the baby's head shape includes ear shift with forehead and orbital asymmetry, one can appreciate the potential impact of the asymmetry on visual motor learning and tracking across midline. Of particular concern is that at this time of rapid learning, the baby is integrating information into an asymmetrical rather than midline body map.25 The lack of visual responsiveness including visual interaction and early tracking behaviors deprive the baby of one of his more advanced methods of receiving information and eliminates a path the baby can use to attract others. Poor visual tracking also diminishes the baby's source of input for looking and moving, which is later adapted to visual motor coordination".27
Mandibular asymmetry is often apparent in the young infant with deformational plagiocephaly.28 This can impact feeding, jaw alignment, and alter the action of the small muscles used for oralmotor activities.
The baby's ability to roll both directions and develop trunk control may also be impaired by plagiocephaly. The baby may be able to roll normally toward the side of the posterior flattening but may have difficulty turning the head to initiate rolling toward the opposite side. The combination of neck tightness and posterior bossing can create a barrier to rolling and experiencing the world on that side of the baby's body. Crossing midline, a key factor in the development of visual motor and upper extremity functioning can be affected by this limitation in cervical rotation. It is also more difficult to develop balanced trunk control and differentiation of the head on the trunk when turning is impaired by either the neck musculature or the occipital bossing of the plagiocephaly. " Head turning, accompanied by neck rotation, facilitates rotational righting reactions between head and trunk and between trunk segments".27
Symmetrical Deformational Brachycephaly
Deformational symmetrical brachycephaly is characterized by a head that is abnormally wide for its length (cephalic ratio greater than 81%). In its most severe presentation the central occipital flattening is accompanied by peaking of the vertex of the head, abnormal widening of the parietal bones, severe sloping of the vertex and pronounced frontal bossing. Argenta reports that the widening of the parietal bones and vertical skull growth is "an attempt at further decompression of the brain by vertical growth or temporal bulging.29
Graham points out that brachycephaly may be associated with syndromes that affect the "pliability of the infant's skull or an infant's tendency to remain recumbent...". Conditions resulting in hypotonia such as Down's Syndrome or those with demineralization like Osteogenesis Imperfecta can lead to severe deformational brachycephaly as will Klippel-Feil sequence."30
In moderate to severe symmetrical brachycephaly, the wide parietal bossing may act as a barrier to rolling and full rotation to each side while the baby is supine. Babies with symmetrical brachcephaly also have poor neck extensors which limit their midline head and neck control.
Asymmetrical Deformational Brachycephaly
Babies with asymmetrical deformational brachycephaly have a head shape with characteristics of plagiocephaly and brachycephaly. The deformity is one of asymmetry and disproportion, and is second only to deformational plagiocephaly in frequency. The cephalic ratio can exceed 100% in the most severe presentation. Typically there is significant parietal/occipital flattening that crosses the posterior midline, with parietal/occipital bossing on the opposite side. There is asymmetry of the vertex height and cranial vault. Neck muscle asymmetry is often an influence on the development of asymmetrical brachycephaly.
The deformity impacts sensory motor development in the same way as it affects deformational plagiocephaly. The baby has difficulty turning the head toward the side of the posterior bossing, reducing visual and auditory experiences to that side. The neck asymmetry also interferes with the initiation of neck motion for rolling to that side. Asymmetry can affect the muscles of the neck and shoulder girdle, impacting midline activities and integration of primitive reflexes like the Asymmetrical Tonic Neck Reflex (ATNR).25
Babies with deformational scaphocephaly have a head shape that is long and disproportionately narrow. It is the least common deformational head shape deformity, and is usually associated with premature infants who are positioned in sidelying in the NICU. The narrow occiput of a skull with a scaphocephalic deformity makes midline positioning of the head difficult, and the baby's head tends to fall over to one side or the other. This impacts the ability to develop neck extension against gravity and midline head and neck control. The visual field is affected because in side-lying, the baby loses contact with events taking place in mid-line and on the opposite side of the body.
Repositioning and Therapeutic Intervention
Prone activities foster the acquisition of motor milestones in addition to relieving pressure from the baby's head. Prone activities also promote neck extension and head turning-and provide opportunities for the baby to stretch and lengthen tight neck and shoulder girdle musculature. Current strategies for treating head shape deformities begin with early identification of the problem and monitoring the baby's head shape at every visit to the pediatrician's office. The AAP recommends that the pediatrician assess the baby for torticollis, advise parents about re-positioning strategies, and refer the baby for therapy if developmental delays, neck weakness or tightness has not resolved with repositioning. Caregivers need to understand how their own child care practices can have a positive or negative effect on the baby's head shape and development.
As always, prevention is the best intervention. First and foremost, prone activities have value because they foster healthy sensory motor development. As a secondary benefit these activities are also effective at relieving pressure on the baby's head and provide a completely free and effective method of preventing head shape deformities. In addition, activities that provide variety and stimulation across positions provide countless opportunities for caregivers to relate to their babies and establish strong bonds.
An excellent resource, Tummy Time Tools, was developed collaboratively by Children's Health Care of Atlanta and Orthomerica Products as part of ACPOC and ACPA poster exhibits in 2003 in an effort to provide activities that caregivers can incorporate into their childcare practices from the very first day of life. This educational piece-now in its second edition-supports the Back to Sleep program, and promotes the inclusion of prone positioning to enhance motor development prevent head shape deformities. This educational resource can be downloaded on www.choa.org and www.starbandkids.com.
Pictures 10a and 10b
Can Cranial Remolding Orthoses Affect Development?
When a cranial remolding orthosis is fabricated, the mold is modified to create symmetry in the flattened quadrants. This more rounded occipital portion of the orthosis allows the baby's head to turn more freely instead of resting on the flattened area of the occiput. The bossing of the baby's head no longer acts as a barrier to rolling, and while wearing the orthosis, the baby can begin to turn and roll, facilitating midline control and the development of more advanced motor skills.
The orthosis provides space in the affected flattened areas to prevent further deformity at night when the baby is supine and when the baby is positioned for protection in the car seat. No study has ever documented that cranial remolding orthoses interfere with skill or brain development. There is evidence, however, that prior to any orthotic intervention, babies with deformational plagiocephaly have developmental, auditory, and visual motor issues. Many caregivers report that their babies begin to roll and are more active after they begin orthotic treatment.
Pictures 11 and 12
Babies may still have head shape deformities even when caregivers provide a perfect variety of prone experiences. Cranial remolding orthoses are well-tolerated by babies and caregivers, and offer timely correction of head shape deformities in young babies. When prone activities and therapeutic interventions fail to address the baby's moderate to severe skull deformity, orthotic care provided between 3 and 18 months of age can correct head shape deformities and positively influence sensory motor skill development in young babies.
Dulcey Lima, Orthomerica
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