BMJ 2014;348:g2741 doi: 10.1136/bmj.g2741 (Published 1 May 2014)

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Research

Helmet therapy in infants with positional skull
deformation: randomised controlled trial
OPEN ACCESS
1

Renske M van Wijk PhD candidate , Leo A van Vlimmeren senior researcher in paediatric23
1
physiotherapy , Catharina G M Groothuis-Oudshoorn biostatistician , Catharina P B Van der Ploeg
41epidemiologist , Maarten J IJzerman professor , Magda M Boere-Boonekamp associate professor
1of youth health care
Department Health Technology and Services Research, Institute of Innovation and Governance Studies, University of Twente, Drienerlolaan 5,7522 NB, Enschede, Netherlands; 2Department of Rehabilitation, Paediatric Physical Therapy, Radboud university medical center, Nijmegen,
Netherlands; 3Scientific Institute for Quality of Healthcare, Radboud university medical center, Nijmegen, Netherlands; 4TNO Child Health, Leiden,
Netherlands
1

Abstract
Objective To determine the effectiveness of helmet therapy for positionalskull deformation compared with the natural course of the condition in
infants aged 5-6 months.
Design Pragmatic, single blinded, randomised controlled trial (HEADS,
HElmet therapy Assessment in Deformed Skulls) nested in a prospective
cohort study.
Setting 29 paediatric physiotherapy practices; helmet therapy wasadministered at four specialised centres.
Participants 84 infants aged 5 to 6 months with moderate to severe
skull deformation, who were born after 36 weeks of gestation and had
no muscular torticollis, craniosynostosis, or dysmorphic features.
Participants were randomly assigned to helmet therapy (n=42) or tonatural course of the condition (n=42) according to a randomisation planwith blocks of eight.
Interventions Six months of helmet therapy compared with the natural
course of skull deformation. In both trial arms parents were asked to
avoid any (additional) treatment for the skull deformation.
Main outcome measures The primary outcome was change in skull
shape from baseline to 24 months of age assessed usingplagiocephalometry (anthropometric measurement instrument). Change
scores for plagiocephaly (oblique diameter difference index) andbrachycephaly (cranioproportional index) were each included in ananalysis of covariance, using baseline values as the covariate. Secondary
outcomes were ear deviation, facial asymmetry, occipital lift, and motor
development in the infant, quality of life (infant and parent measures),and parental satisfaction and anxiety. Baseline measurements were

performed in infants aged between 5 and 6 months, with follow-up
measurements at 8, 12, and 24 months. Primary outcome assessment
at 24 months was blinded.
Results The change score for both plagiocephaly and brachycephaly
was equal between the helmet therapy and natural course groups, witha mean difference of −0.2 (95% confidence interval −1.6 to 1.2, P=0.80)
and 0.2 (−1.7 to 2.2, P=0.81), respectively. Full recovery was achievedin 10 of 39 (26%) participants in the helmet therapy group and 9 of 40(23%) participants in the natural course group (odds ratio 1.2, 95%
confidence interval 0.4 to 3.3, P=0.74). All parents reported one or moreside effects.
Conclusions Based on the equal effectiveness of helmet therapy andskull deformation following its natural course, high prevalence of side
effects, and high costs associated with helmet therapy, we discourage
the use of a helmet as a standard treatment for healthy infants withmoderate to severe skull deformation.
Trial registration Current Controlled Trials ISRCTN18473161.

Introduction
Positional skull deformation is a condition in which the shapeof an infant’s skull deforms as a result of prolonged external
forces. The infant’s head is malleable and growing rapidly,
hence it is susceptible to deformation, especially when infants
develop a positional preference of the head when lying in thesupine position.1 Two typical components of skull deformation
are unilateral occipital flattening of the skull (plagiocephaly)and symmetrical occipital flattening (brachycephaly).2 A strong
plagiocephalic flattening is often presented with ipsilateral

Correspondence to: R M van Wijk University of Twente, PO Box 217, 7500 AE, Enschede, Netherlands r.m.vanwijk@utwente.nl
Extra material supplied by the author (see http://www.bmj.com/content/348/bmj.g2741?tab=related#webextra)
Components of skull deformation: (A) plagiocephaly, (B) brachycephaly
Baseline characteristics of participants versus non-participants
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RESEARCH

BMJ 2014;348:g2741 doi: 10.1136/bmj.g2741 (Published 1 May 2014)

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RESEARCH

Skull deformation is generally considered a cosmetic condition.
Developmental delays are regularly associated with skull
deformation,6-9 but the deformation is increasingly seen as amarker for delays, instead of causing the delays.6-8 Parents fear
the negative physical and psychosocial effects of skull
deformation on their child.10 11

The prevalence of skull deformation increased substantiallyafter it was recommended that infants should be placed in asupine sleep position to prevent sudden infant death
syndrome.12-18 Nowadays skull deformation seems most prevalent
between two (16-22%) and four months (20%) after birth.19 20
The prevalence drops when infants become older.1 19-21
The preferred treatment is usually conservative. In a recently
published guideline (2012), the Netherlands Centre of PreventiveChild Health Care advised to start counselling parents during
well baby visits on the handling and repositioning infants withan observed positional preference or skull deformation. Whenno improvement is seen at follow-up visits, infants are referred
for paediatric physiotherapy.22 23 Infants younger than 4 months
may benefit from active repositioning, yet not all show
improvement.22 24 25 As most infants show symmetry in posture
at 5 or 6 months of age,1 22 no effects of continued paediatricphysiotherapy can be expected. In infants with persistent skull
deformation at 6 months of age, orthotic helmets or headbands
are often prescribed.26-28 A helmet is a cranial orthosis made up
of a rigid plastic shell with a foam lining. The helmet is expected
to redirect skull growth by fitting closely to the infant’s headbut leaving room for the skull to grow at the flattened area. The
helmet is recommended to be worn for 23 hours a day from 6
to 12 months of age. In the Netherlands 1-2% of infants (176000 newborns in 201229) received helmet therapy for skull
deformation.
Since conclusive evidence from randomised trials is lacking,the clinical benefit of helmet therapy compared with the natural
course of skull deformation remains unknown. The few
prospective comparative studies to date tend to show positive
results in favour of helmet therapy but have several
limitations.5 30-33 Long term outcomes and assessment of side
effects are missing in most studies and the clinical relevance ofthe reported effects is questionable.26 28 34 35

The HElmet therapy Assessment in Deformed Skulls (HEADS)
study is a randomised controlled trial designed to compare
helmet therapy for six months with the natural course of
positional skull deformation in infants aged 6 months. Althoughhelmet therapy is expected to give slightly better results in the
short term, we hypothesised that the natural course of skull
deformation would catch up with the effects of helmet therapy
over time and that no clinically meaningful differences would
be present between the two groups at 2 years of age.

Methods

Study design
The HEADS study is a two armed pragmatic randomised
controlled trial nested in a prospective cohort study (fig 1⇓).
The follow-up study was designed to catch all infants eligiblefor helmet therapy after a period of paediatric physiotherapy ora single consultation. We invited the parents of eligible infants
with moderate to severe skull deformation to include their childin the study at 5 months of age. Participants were randomised
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1:1 to either the helmet therapy arm or the natural course arm.
Follow-up assessments were performed at 8, 12, and 24 monthsof age (fig 1). The primary outcome was anthropometricmeasurement of the skull. A more detailed description of the
HEADS study is published elsewhere.36

Setting and participants
Recruitment for the randomised controlled trial was conductedin 29 paediatric physiotherapy practices in the east of theNetherlands between July 2009 and July 2011 by 29 speciallytrained paediatric physiotherapists. We considered infants to beeligible for the study if they had moderate to severe skull
deformation, were aged 5 to 6 months, were born after 36 weeks
of gestation, and had no muscular torticollis, craniosynostosis,or dysmorphic features. The course for participating paediatricphysiotherapists included detailed information on differentiating
between synostotic and non-synostotic skull deformation andbetween positional and congenital muscular torticollis.
We determined the severity of skull deformation in thetransversal plane using the oblique diameter difference index
and the cranioproportional index of plagiocephalometry (fig2⇓).37 38 The oblique diameter difference index provides thedegree of the plagiocephalic component of skull deformationand is the ratio between the longest cranial diagonal and theshortest cranial diagonal (fig 2) multiplied by 100%, with both
located at 40° from the anterior-posterior line. In addition, we
determined the brachycephalic component using the
cranioproportional index, which is the ratio between the width
and the length of the skull (fig 2).

We included infants in the study if the oblique diameter
difference index was 108% or more or if the cranioproportional
index was 95% or more, or in the case of a mixed form if theoblique diameter difference index was 106% or more and thecranioproportional index was 92% or more. Infants with very
severe skull deformation were excluded (oblique diameter
difference index >113% or cranioproportional index >104%).
A value of 100% on the oblique diameter difference index
represents a symmetrical head shape. A value of more than
100% represents asymmetrical skull deformation; the higher
the score, the more severe the deformation. A score of 80% on
the cranioproportional index represents an average head shapein Western countries. A higher value represents a larger headwidth compared with length.

Randomisation and blinding
At age 5 months, the paediatric physiotherapists selected infants
meeting the inclusion criteria for the trial and requested informed
consent from the parents. The parents could consult an
independent doctor for questions related to trial participation.
After inclusion, infants were allocated to their trial arm bycomputer generated randomisation in blocks of eight. An
independent researcher managed the randomisation plan. The
research team and parents were blinded for group allocation
until the parents had signed the informed consent form andconfirmed participation. A researcher (RMW) called the parents
and informed them about the randomisation allocation. It was
not possible to blind parents during the treatment period. The
infant’s paediatric physiotherapist, general practitioner, andyouth healthcare professional were informed about group
allocation after randomisation. Blinded outcome assessments
were, however, performed at the 24 month follow-up.

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frontal bossing of the forehead and anterior shift of the ipsilateralear (ear deviation) and cheek (see web extra fig 1A).3-5
Brachycephaly can be accompanied by temporal bossing or an
occipital lift (see web extra fig 1B).3

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RESEARCH

Intervention and control group

The control group did not receive helmet therapy and naturalskull growth was monitored.

Outcome measures
The paediatric physiotherapists performed measurements atbaseline and at age 5, 8, and 12 months. Six of the paediatricphysiotherapists who were involved in the study were selected
to perform the blinded assessments at 24 months in all infants.
These measurements were carried out from February 2011 until
March 2013. Every assessment included anthropometricmeasurement of the skull’s shape, a clinical assessment of skull
deformation, a motor assessment, and a parental questionnaire.
The questionnaire was used to gather information on backgroundcharacteristics (sex, age, birth rank, health problems, ethnicity,and educational level of the parents) at baseline and parent
reported outcomes during all assessments.

Therapy compliance
The questionnaire administered at 12 months was used todetermine whether parents were compliant with the regimen towhich their infant was assigned. The questionnaire assessed theage of infants when treatment was discontinued and the reasonsfor discontinuation. Parents were also asked whether they usedadditional therapies. Furthermore, the questionnaires at 8 and12 months also included questions about the fit of the helmet.
Originally the protocol specified that compliance would bedetermined using data from an electronic device built into thehelmet to measure compliance with wear. Despite a pilot study,
data from the measuring devices proved to be unreliable andwe therefore omitted them from further analysis.

Primary outcome
Skull shape

The primary outcome was the anthropometric measurement of
the skull’s shape at 24 months using the oblique diameter
difference index and cranioproportional index.37 38 We
considered a difference in change score from age 5 to 24 monthsof 4 oblique diameter difference index points or 5
cranioproportional index points to be relevant between thegroups, consistent with one level of severity in skull deformationaccording to plagiocephalometry criteria (fig 2). Additionally,
we report the number of infants who fully recovered, with fullrecovery defined as an oblique diameter difference index of lessthan 104% and a cranioproportional index of less than 90% (fig2).
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Severity of ear deviation was expressed by the ear deviationindex using plagiocephalometry. The ear deviation index is theratio between the ear deviation and the length of the skull (fig2).

Facial asymmetry and occipital lift

During the clinical assessment the paediatric physiotherapists
reported the presence of any facial asymmetry and occipital lift.

Parental satisfaction

Parental satisfaction with their infant’s head shape was assessedin the parental questionnaire using a five point Likert scale,ranging from 1 (not satisfied at all) to 5 (very satisfied).

Motor development

At baseline, a paediatric physiotherapist assessed the repertoireof gross motor movement using the Alberta infant motor scale,a valid, norm-referenced measurement. We converted raw scoreson the scale into standardised Z scores, using the formula:(individual score−average score)/standard deviation.39

To assess motor development at 24 months we used the Bayley
scales of infant and toddler development, third edition.40
Specially trained physiotherapists administered the test. We
converted raw scores to standardised motor composite scores(mean 100 (SD 15)) and scaled scores for fine and gross motor
development separately (mean 10 (SD=3)).

Parental anxiety

We measured the level of parental state anxiety using theSpielberger state trait anxiety inventory, Dutch version.41 The
state anxiety scale (20 items) concerns the state of anxiety ofparents at a specific moment, and scores range from 20 to 80;
a higher score represents a higher state of anxiety.

Quality of life

The infant toddler quality of life questionnaire—short form 47
is a parent reported measure that provides information about
the health status and health related quality of life in children
aged between 2 months and 5 years.42 Since the questionnaire
is a “proxy” measure and parental concern might influence
outcomes, parent specific scales are included. The questionnaire
consists of eight multi-item scales and two single items: thechild scales include physical abilities (six items), growth anddevelopment (five), bodily pain (two), temperament and moods(six), behaviour (12), general health (six), and change in health(one); the parent scales include parental-impact emotional (fouritems), parental-impact time (four), and family cohesion (one).
Scores for all scales range from 0 to 100, with a higher scoreindicating better health.

Side effects
The questionnaires at 8 and 12 months contained questions
about side effects associated with helmet therapy. In consultation
with health professionals we defined side effects as skinirritation, pain, sweating, odour of the helmet, problems withaccepting the helmet, and feeling hindered in cuddling becauseof the helmet. Furthermore, in both groups at 8 months parents
were asked about the number of hours their baby cried a day
and whether their baby had sleep problems. Criteria to define
sleep problems in infants are not used consistently in the
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Parents of infants allocated to the helmet therapy group wereasked to make an appointment at one of the four collaborating
institutes to obtain a custom-made helmet. Between the institutes
two brands of helmets were provided; both helmets used thesame mechanism to redirect skull growth. The aim was to starthelmet therapy in the infants no later than 6.5 months of age.
Parents were instructed to ensure that the helmet was worn for
23 hours a day until their infant was 12 months of age or until
satisfactory outcomes were obtained according to both parents
and professionals. Parents received additional information on
starting the helmet therapy, how the helmet should be worn,cleaning the helmet, and general care. An orthotist regularly
monitored the infants for signs of pressure spots, and the helmet
was modified or replaced to accommodate skull growth asnecessary. The treatment was always supervised by a (paediatric)
doctor. During the intervention period, Dutch health insurancecompanies reimbursed the costs of helmet therapy.

Secondary outcomes
Ear deviation

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Statistical analyses
The sample size of the randomised controlled trial of the
HEADS study was calculated at 72 (36 in each arm), based ona significance level of 5%, a power of 90%, and a difference inmean improvement of at least 4 (SD 6) oblique diameter
difference index points.

We described background and baseline clinical characteristicsof the sample for the total group as well as for the intervention
and control groups separately; continuous variables with means
and standard deviation, and discrete variables with counts andpercentages. In a subsequent analysis, we compared the baselinecharacteristics of the intervention and control groups by meansof the independent t test or χ2 test. We determined therepresentativeness of the randomised controlled trial populationby comparing background characteristics and baseline clinicalcharacteristics of the population with eligible non-participants
at age 5 months using the independent t test or χ2 test.

For analysis we used two continuous outcome variables(plagiocephaly change score: oblique diameter difference index
at age 5 months minus 24 months; and brachycephaly change
score: cranioproportional index at age 5 months minus 24
months) and the dichotomous outcome variable (full recovery).
Treatment effect was presented as change score in the helmet
therapy group minus change score in the natural course group.
To test differences in the change scores between the groups, weused analysis of covariance with baseline value (age 5 months)
as covariate. Thereafter we carried out multiple regression
analyses with baseline values (age 5 months), sex, and parental
level of education as covariates. We compared secondary
outcomes between groups by means of the independent t testor χ2 test. To analyse the 10 subscales of the infant toddler
quality of life questionnaire we performed a multivariate analysis
of variance.
We compared the groups on an intention to treat basis.
Additionally, we carried out a per protocol analysis. Data
analysis was performed using SPSS (version 21.0), and we set
the level of significance at 0.05.

Results

Study population
At the start of this study, the paediatric physiotherapists
identified 403 eligible infants (47% of 866 assessed infants, fig1). The parents of 84 infants (21%) agreed to participate in thetrial and those infants were assigned to two groups (42 infantsin each group). The main baseline personal and clinicalcharacteristics (sex, age, birth rank, health problems, ethnicity,
severity of skull deformation, motor development, and parental
satisfaction) did not differ significantly between those who
agreed to participate and the infants who were not enrolled,
except for the educational level of the parents, which was lower
among the participants (see web extra table). The backgroundcharacteristics of the two trial arms were comparable (table 1⇓).
A total of 79 infants (94%) were followed up at the final
assessment at 24 months (fig 2). The parents of two infants did
not show up for final assessments despite repeated attempts tocontact them, two families moved out of the study area, and theparents of one infant could not be contacted.

index ≥108%) or the brachycephalic component(cranioproportional index ≥95%), or both. The baseline
assessments showed statistically significant differences in the
shape of the infants’ skulls between the two groups (table 2⇓).
Infants in the natural course group presented with more severe
plagiocephaly and more often presented with facial asymmetry,
whereas infants in the helmet therapy group showed higher
brachycephaly scores and more often showed the accompanying
occipital lift (table 2).

Therapy allocation and compliance
After randomisation, seven infants did not start the assigned
treatment. Six infants who were allocated to helmet therapy did
not start this treatment: in three cases the parents preferred toallow the skull deformity to follow its natural course; in threeother cases the doctor advised against helmet therapy.
Additionally, parents of one infant allocated to the natural course
arm preferred helmet therapy.

In infants who started in the helmet therapy group, helmet
therapy was discontinued at a mean age of 10.0 months (SD 2.0
months, n=30). Ten of 30 infants received helmet therapy until
12 months of age. The main reasons for parents discontinuing
the helmet therapy before 12 months (n=20) was satisfaction
with results (n=8), side effects (n=10), dissatisfaction with theresults (n=1), and “other” (n=1). Problems with fitting the helmet
were reported for 22 of 30 infants (73%); the helmet rotated or
shifted a few times a week to several times a day. Parents of
one infant reported that the helmet came off spontaneously.
Two infants in the natural course group received helmet therapy
after the 8 month assessment; the parents were not satisfied withthe skull shape.

Three infants in the helmet therapy group and two in the natural
course group received additional therapy during the intervention
period: manual therapy, osteopathy, or chiropractic.

Primary outcome
The plagiocephaly change score from age 5 months to 24 months
was almost equal for both groups (table 3⇓): the difference inoblique diameter difference index, calculated as change scorein the helmet therapy group minus change score in the natural
course group, was −0.2 (95% confidence interval −1.6 to 1.2,
P=0.80). The brachycephaly change score from age 5 months
to 24 months was also almost equal for both groups, with adifference in cranioproportional index of 0.2 (−1.7 to 2.2,
P=0.81). Additionally, the numbers of infants showing fullrecovery were comparable in both groups (odds ratio 1.2, 95%
confidence interval 0.4 to 3.3).
When adjusting for baseline values, change scores between
groups did not differ significantly (adjusted difference in mean
plagiocephaly change score 0.9, 95% confidence interval −0.3
to 2.0 and in mean brachycephaly change score −1.0, −2.5 to0.5). Adjusting for sex and parental level of education did notalter the treatment effect (plagiocephaly change score: β=1.0(−0.3 to 2.3), P=0.12; brachycephaly change score: β=−1.1(−2.8 to 0.5), P=0.17).
A per protocol analysis of covariance (helmet therapy n=34,
natural course n=45) provided outcomes comparable to theintention to treat analysis (plagiocephaly change score −0.4,−1.8 to 1.1, P=0.31; brachycephaly change score 0.5, −1.5 to
2.4, P=0.11).

All infants met the inclusion criteria for either the plagiocephaliccomponent of skull deformation (oblique diameter difference
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literature43; in this study we defined sleep problems as taking
more than 20 minutes to fall asleep (daily), or waking more thanonce every night.

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Secondary outcomes

Finally, a multivariate analysis of variance revealed nosignificant differences between groups for subscales on theinfant toddler quality of life questionnaire: Wilks’ λ=.826,
F10,63=1.3, P=0.24.

Side effects
The helmet therapy group had fewer sleep problems (helmet
therapy 5/35, 14%; natural course 10/41, 24%) and spent fewer
hours crying than the natural course group (helmet therapy mean
1.4 (SD 1.2); natural course mean 1.2 (SD 0.9)), although thesedifferences were not significant. In the intervention group all
parents (35/35) reported one or more side effects related tohelmet therapy: problems with acceptance of the helmet (8/33,24%), skin irritation (32/34, 96%), augmented sweating (24/34,71%), unpleasant odour of the helmet (25/33, 76%), pain
associated with the helmet (9/27, 33%), and feeling hinderedfrom cuddling their child (24/31, 77%).

Discussion
This pragmatic randomised controlled trial found no evidenceof a significant or clinically meaningful difference inimprovement of skull shape at 2 years of age between infants
who were treated with helmet therapy and those in whom thenatural course of skull deformation was awaited. Despite
improvement in skull shape in both groups, only a quarter ofthe participants showed full recovery. Overall, parents weresatisfied to very satisfied with the recovery of their infants’ skull
deformation at 2 years old. However, the parents of infants who
were treated with a helmet showed slightly higher satisfaction
scores and a slightly lower state of anxiety when their infants
were 2 years of age.
Helmet therapy did not influence the infants’ motor
development, quality of life, sleeping, or crying. Side effectsof helmet therapy were reported by all parents.

Strengths and limitations of this study
Strengths of this study include the randomised allocation oftreatment, nested design, high follow-up rates, use of various
long term outcomes measures, and both plagiocephaly andbrachycephaly being studied.

The HEADS trial is the first study to provide evidence from arandomised controlled trial on the long term effectiveness ofhelmet therapy for skull deformation. The nested design enables
us to determine the generalizability of study outcomes. As wellas having anthropometric outcome measures, this study
presented parent reported outcomes (for example, subjective
assessments and quality of life assessment) and side effects. A
high follow-up rate of 94% ensures the power of the study andindicates that the follow-up was not selective.

The use of two outcome measures (oblique diameter difference
index and analysis of covariance) could be disputed. However,positional skull deformation usually presents with components
of both brachycephaly and plagiocephaly and not just as one
type or the other.2 Moreover, helmets are prescribed for all
variations of moderate to severe positional skull deformation,so we therefore included both components of skull deformation.

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Despite between group differences in the baseline clinicalcharacteristics at randomization, this was tackled using theplanned analysis of covariance for the comparison of meandifferences. The improvement assessed by anthropometricmeasurements showed no differences at 24 months, yet theparents of infants in the helmet therapy group showed slightly
higher satisfaction scores and lower anxiety levels. This might
be explained by the fact that simply offering treatment may
reassure parents.

The parents of 21% of eligible infants agreed to participate in
the trial. Participating parents had a lower level of education
than non-participating parents. It has been described before thatparents with a higher level of education might have stronger
preferences for treatment and are thereby less likely to agreewith randomisation.44 45
Another limitation of the study is that the results concern infants
with moderate to severe skull deformation and therefore are notgeneralisable to cases of very severe skull deformation. We
decided to exclude very severe cases, since we expected
selection bias on the basis of severity of the deformation andselective loss to follow-up in infants with very severe skull
deformation who would have been allocated to the natural
course. Eventually, only 29/432 (7%) of infants who were
eligible for helmet therapy at age 5 months were excluded on
the basis the severity of skull deformation. Results are also not
generalisable to infants with an underlying congenital conditionor muscular torticolllis, or infants who were born preterm.
Inclusion of infants born preterm would have complicated thetreatment protocol and the interpretation of outcomes. The
prevalence of positional skull deformation in infants born
preterm is high, but the natural course seems favourable.46
Additionally, in infants born preterm the corrected age has tobe used for the start of treatment and outcome measurements,
which would have complicated interpretation and thegeneralisability of study outcomes.

A final limitation is that we were not able to study the exact
wear time of the helmet. However, in this pragmatic study wewanted to study the effect of helmet therapy in routine everyday
practice, including parent instructions and regular check-ups tomonitor treatment and assess improvements in skull shape.

Strengths and weaknesses in relation to otherstudies
The various literature reviews suggest that helmet therapy may
be more effective in correcting skull deformation in infants aged
6 months than other conservative treatments, but urge the needfor evidence from randomised controlled trials.26 28 34 35 47
Contrary to the present study, a recent study advocated the useof a helmet for moderate to severe skull deformation. Both thisand our study had an equal intervention period: therapy started
at 6 months of age and ended at 10 months on average. However,
the recent study was a non-randomised study with no blindedassessors, using different time intervals of follow-up and a
non-validated outcome measure.30
Previous studies often did not comprise long term outcomesand systematic assessment of side effects. One retrospective
study described how 22.4% of infants experienced side effectsof helmet therapy. This is in contrast with our study, in whichside effects were reported in all infants, probably because we

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No significant differences were found for the additional clinicaloutcomes, parent reported outcomes, and motor development.
Parents in both arms showed high scores for satisfaction with
their infants’ skull shape at 24 months (table 4⇓).

Limitations of this study include the difference of severity ofskull deformation at baseline between both arms of the trial, alow participation rate, limited generalisability of study results
to specific subgroups of infants, and no assessment of daily
wearing time of the helmet.

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In both arms of this study, brachycephaly showed a morefavourable course of recovery than plagiocephaly. A cohort
study of 129 infants with skull deformation at age 6 months
showed comparable results at age 4 years when the natural
course was awaited: the improvement in plagiocephaly (obliquecranial length ratio at age 6 months: 108.6 (SD 3.3); age 4 years:
105.4 (SD 2.6)) is almost equal to the mean change score at age
5 months to 24 months of the natural course group (obliquediameter difference index 3.1 (SD 3.3)) in the present study.
The improvement of brachycephaly (cephalic index at age 6months: 92.6 (SD 6.6); age 4 years: 87.0 (SD 4.7)) is also inline with findings in the natural course group in the present
study (change score on cranioproportional index from 5 months
to 24 months 6.8 (SD 4.4)).21
Finally, interpreting parent reported outcomes can be difficult.
As in other studies, the objective outcomes in this study did notmatch the subjective assessments.27 49 50 Non-clinical factors
may be as important as clinical factors in assessments ofsatisfaction.51

Practice implications
This study indicates that helmet therapy has no added value inthe treatment of moderate to severe skull deformation in healthy
infants. A cost study performed in both arms of the present
study, parallel to the HEADS effectiveness study, showed thatthe total costs per infant treated with a helmet were substantiallyhigher (n=20, €1401; £1157; $1935) than for infants in whom
the natural course of skull deformation was awaited (n=14,€157).52 Based on the equal effectiveness of helmet therapy
compared with the natural course, the high prevalence of side
effects and the high costs of treatment, we discourage the useof helmet therapy as a standard treatment for healthy infants
with moderate to severe skull deformation. Outcomes are
expected to hold for all types of custom-made helmets
comprising a rigid plastic shell with a foam lining that aredesigned to fit snugly over the infant’s head and leaving room
for skull growth at the flattened area.
This conclusion is therefore likely to affect decisions of parents,
policymakers, insurance companies, and a wide range ofclinicians such as paediatricians, general practitioners, youth
healthcare professionals, paediatric physiotherapists, orthotists,
paediatric neurosurgeons, and craniofacial surgeonsinternationally.
Our study also indicated that 75% of infants continued to havesome degree of skull deformation at 2 years of age, mainly theplagiocephalic component. Skull deformation does notcompletely resolve in all cases by natural course, and helmet
therapy does not seem to have an added value for recovery.
Therefore we emphasise the importance of prevention, early
detection, and early treatment with paediatric physiotherapy ofskull deformation.22 35 47 Additionally, our cut-off points for
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normal head shape might be rigid in comparison with others.2 53
Therefore, the 75% of infants with persisting skull deformationin the present study could be an overestimation of the prevalenceof the condition at an older age. It remains arguable what an
acceptable head shape is in young infants and at an older age
when the head is covered with hair.

Unanswered questions and future researchThis is the first randomised controlled trial on helmet therapy
in infants with positional skull deformation. Although we
conclude no significant difference, this study was not poweredfor equivalence. Ideally, the study should be repeated with anadequate sample size to confirm the non-inferiority of helmet
therapy. However, we question whether aiming for anotherrandomised controlled trial will be realistic since helmet therapy
is not reimbursed in most countries. Results from the HEADS
non-randomised controlled trial will be presented in the near
future and might provide additional evidence to set next to theresults of the present randomised controlled trial. Future researchshould determine the effects of helmet therapy in very severe
skull deformation.
We thank the parents and infants for participating in the HEADS study;
the paediatric physiotherapists for recruiting participants and acquiring
the data; the orthotists and (paediatric) doctors, who provided helmet
therapy, for their willingness to cooperate with the HEADS study; Henk
Wierenga, for his role as independent adviser to parents; youth
healthcare professionals in the study area for supporting the HEADS
study; Marjon Rouwette-Witting and Jorien Pierik for managing therandomisation plan; Carine Doggen for reading and editing themanuscript before submission; and the HEADS project group, HEADS
project group advisors, TNO Child Health, and the Royal Dutch Society
for Physical Therapy for their collaboration.
Contributors: RMW was responsible for the day to day management of
the trial, development of the trial, data collection, and the first draft ofthe manuscript. MMB, CGMG, CPBP, LAV, and MJIJ conceived anddesigned the HEADS study and obtained funding. MMB, LAV, and MJIJ
supervised the study. LAV and RMW trained the trial assessors(paediatric physiotherapists). RWM and CGMG performed the data
analysis. All authors interpreted the data and critically revised themanuscript for important intellectual content, had full access to all of
the data in the study, and can take responsibility for the integrity of thedata and the accuracy of the data analysis. MMB is the guarantor.
Funding: This study was funded by ZonMw, the Netherlands
Organization for Health Research and Development (grant No
170.992.501). Besides the initial review process before funding andamendments, ZonMw had no involvement in the study design,
management of the study, data analysis, writing, and publications. All
researcher activities were independent of the funding source.
Competing interests: All authors have completed the ICMJE uniform
disclosure form at www.icmje.org/coi_disclosure.pdf and declare: nosupport from any organisation for the submitted work; no financial
relationships with any organisations that might have an interest in thesubmitted work in the previous three years; no other relationships oractivities that could appear to have influenced the submitted work.
Ethical approval: This study was approved by the medical ethics
committee of Medisch Spectrum Twente, hospital of Enschede,
Netherlands, 8 January 2009 (reference NL24352.044.08).
Data sharing: Relevant patient level data are available from thecorresponding author on reasonable request. Informed consent for data
sharing was not obtained but the presented data are anonymised.
Transparency: The manuscript’s guarantor affirms that this manuscript
is an honest, accurate, and transparent account of the study being
reported; that no important aspects of the study have been omitted; andSubscribe: http://www.bmj.com/subscribe

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used a broader definition of side effects and side effects wereself reported by the parents.48 Additionally, the clinical meaningof the effects of helmet therapy presented in previous studies
can be disputed.34 In the present study we defined a clinicallymeaningful difference as 4 oblique diameter difference index
points or 5 cranioproportional index points, consistent with one
level of severity in skull deformation according toplagiocephalometry criteria (fig 2). We chose this cut-off point
based on expert opinion, and it should represent a difference
that is clinically visible. Both our randomised study design andits focus on clinically meaningful differences, rather than justsignificant differences, are strengths of this study comparedwith previous studies.

BMJ 2014;348:g2741 doi: 10.1136/bmj.g2741 (Published 1 May 2014)

Page 7 of 13

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What is already known on this topic
Helmet therapy is often prescribed in infants with positional skull deformation
Evidence from randomised controlled trials for the effectiveness of helmet therapy compared with the natural course of the condition islacking

What this study adds
No effect of helmet therapy can be shown in infants with moderate to severe positional skull deformation
All parents reported side effects; however, helmet therapy did not influence infants’ motor development or health related quality of lifethat any discrepancies from the study as planned (and, if relevant,registered) have been explained.
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5
6
7
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9
10
11
12
13
14
15
16
17
18
19
20
21
22

23
24

25

26
27
28
29

Boere-Boonekamp MM, van der Linden-Kuiper LT. Positional preference: prevalence ininfants and follow-up after two years. Pediatrics 2001;107:339-43.
Meyer-Marcotty P, Bohm H, Linz C, Kochel J, Blecher C, Keil N, et al. Spectrum of
positional deformities—is there a real difference between plagiocephaly andbrachycephaly? J Craniomaxillofac Surg 2014 (in press).
Argenta L, David L, Thompson J. Clinical classification of positional plagiocephaly. J
Craniofac Surg 2004;15:368-72.
Clarren SK. Plagiocephaly and torticollis: etiology, natural history, and helmet treatment.
J Pediatr 1981;98:92-5.
Mulliken JB, Vander Woude DL, Hansen M, LaBrie RA, Scott RM. Analysis of posterior
plagiocephaly: deformational versus synostotic. Plast Reconstr Surg 1999;103:371-80.
Collett BR, Gray KE, Starr JR, Heike CL, Cunningham ML, Speltz ML. Development atage 36 months in children with deformational plagiocephaly. Pediatrics 2013;131:e109-15.
Hutchison BL, Stewart AW, Mitchell EA. Characteristics, head shape measurements anddevelopmental delay in 287 consecutive infants attending a plagiocephaly clinic. Acta
Paediatr 2009;98:1494-9.
Kennedy E, Majnemer A, Farmer JP, Barr RG, Platt RW. Motor development of infants
with positional plagiocephaly. Phys Occup Ther Pediatr 2009;29:222-35.
Kordestani RK, Patel S, Bard DE, Gurwitch R, Panchal J. Neurodevelopment delays inchildren with deformational plagiocephaly. Plast Reconstr Surg 2006;117:207-18.
Collett B, Breiger D, King D, Cunningham M, Speltz M. Neurodevelopmental implicationsof “deformational” plagiocephaly. J Dev Behav Pediatr 2005;26:379-89.
Steinbok P, Lam D, Singh S, Mortenson PA, Singhal A. Long-term outcome of infants
with positional occipital plagiocephaly. Childs Nerv Syst 2007;23:1275-83.
Argenta LC, David LR, Wilson JA, Bell WO. An increase in infant cranial deformity withsupine sleeping position. J Craniofac Surg 1996;7:5-11.
De Jonge GA, Engelberts AC, Koomen-Liefting AJ, Kostense PJ. Cot death and prone
sleeping position in The Netherlands. BMJ 1989;298:722.
Dwyer T, Ponsonby AL, Blizzard L, Newman NM, Cochrane JA. The contribution ofchanges in the prevalence of prone sleeping position to the decline in sudden infant death
syndrome in Tasmania. JAMA 1995;273:783-9.
Fleming PJ, Gilbert R, Azaz Y, Berry PJ, Rudd PT, Stewart A, et al. Interaction between
bedding and sleeping position in the sudden infant death syndrome: a population based
case-control study. BMJ 1990;301:85-9.
Kane AA, Mitchell LE, Craven KP, Marsh JL. Observations on a recent increase inplagiocephaly without synostosis. Pediatrics 1996;97(6 Pt 1):877-85.
Turk AE, McCarthy JG, Thorne CH, Wisoff JH. The “back to sleep campaign” anddeformational plagiocephaly: is there cause for concern? J Craniofac Surg 1996;7:12-8.
American Academy of Pediatrics AAP Task Force on Infant Positioning and SIDS:
positioning and SIDS. Pediatrics 1992;89(6 Pt 1):1120-6.
Hutchison BL, Hutchison LA, Thompson JM, Mitchell EA. Plagiocephaly and brachycephaly
in the first two years of life: a prospective cohort study. Pediatrics 2004;114:970-80.
Van Vlimmeren LA, van der Graaf Y, Boere-Boonekamp MM, L’Hoir MP, Helders PJM,
Engelbert RHH. Risk factors for deformational plagiocephaly at birth and at 7 weeks ofage: a prospective cohort study. Pediatrics 2007;119:e408-18.
Hutchison BL, Stewart AW, Mitchell EA. Deformational plagiocephaly: a follow-up of head
shape, parental concern and neurodevelopment at ages 3 and 4 years. Arch Dis Child
2010;96:85-90.
Van Vlimmeren LA, van der Graaf Y, Boere-Boonekamp MM, L’Hoir MP, Helders PJ,
Engelbert RH. Effect of pediatric physical therapy on deformational plagiocephaly inchildren with positional preference: a randomized controlled trial. Arch Pediatr Adolesc
Med 2008;162:712-8.
Nederlands Centrum Jeugdgezondheid. JGZ-richtlijn preventie, signalering en aanpak
van voorkeurshouding en schedelvervorming. TNO innovation for life, 2012.
Cabrera-Martos I, Valenza MC, Benitez-Feliponi A, Robles-Vizcaino C, Ruiz-Extremera
A, Valenza-Demet G. Clinical profile and evolution of infants with deformational
plagiocephaly included in a conservative treatment program. Childs Nerv Syst
2013;29:1893-8.
Persing J, James H, Swanson J, Kattwinkel J; American Academy of Pediatrics Committee
on Practice and Ambulatory Medicine, Section on Plastic Surgery and Section on
Neurological Surgery.. Prevention and management of positional skull deformities in
infants. Pediatrics 2003;112:199-202.
Flannery AB, Looman WS, Kemper K. Evidence-based care of the child with deformational
plagiocephaly, part II: management. J Pediatr Health Care 2012;26:320-31.
Kluba S, Kraut W, Reinert S, Krimmel M. What is the optimal time to start helmet therapy
in positional plagiocephaly? Plast Reconstr Surg 2011;128:492-8.
Xia JJ, Kennedy KA, Teichgraeber JF, Wu KQ, Baumgartner JB, Gateno J. Nonsurgicaltreatment of deformational plagiocephaly: a systematic review. Arch Pediatr Adolesc Med
2008;162:719-27.
Statistics Netherlands. Population; sex, age, origin and generation, 1 January. Den
Haag/Heerlen Statistics Netherlands, 2013.

No commercial reuse: See rights and reprints http://www.bmj.com/permissions

30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53

Kluba S, Kraut W, Calgeer B, Reinert S, Krimmel M. Treatment of positional
plagiocephaly—helmet or no helmet? J Craniomaxillofac Surg 2014 (in press).
Lipira AB, Gordon S, Darvann TA, Hermann NV, Van Pelt AE, Naidoo SD, et al. Helmet
versus active repositioning for plagiocephaly: a three-dimensional analysis. Pediatrics
2010;126:e936-45.
Loveday BP, de Chalain TB. Active counterpositioning or orthotic device to treat positional
plagiocephaly? J Craniofac Surg 2001;12:308-13.
Vles JS, Colla C, Weber JW, Beuls E, Wilmink J, Kingma H. Helmet versus nonhelmet
treatment in nonsynostotic positional posterior plagiocephaly. J Craniofac Surg
2000;11:572-4.
Goh JL, Bauer DF, Durham SR, Stotland MA. Orthotic (helmet) therapy in the treatmentof plagiocephaly. Neurosurg Focus 2013;35:E2.
Robinson S, Proctor M. Diagnosis and management of deformational plagiocephaly. J
Neurosurg Pediatr 2009;3:284-95.
Van Wijk RM, Boere-Boonekamp MM, Groothuis-Oudshoorn CG, van Vlimmeren LA,
IJzerman MJ. HElmet therapy Assessment in infants with Deformed Skulls (HEADS):
protocol for a randomised controlled trial. Trials 2012;13:108.
Van Adrichem LNA, van Vlimmeren LA, Cadanova D, Helders PJM, Engelbert RHH, vanNeck HJW, et al. Validation of a simple method for measuring cranial deformities(plagiocephalometry). J Craniofac Surg 2008;19:15-21.
Van Vlimmeren LA, Takken T, van Adrichem LN, van der Graaf Y, Helders PJ, Engelbert
RH. Plagiocephalometry: a non-invasive method to quantify asymmetry of the skull; areliability study. Eur J Pediatr 2006;165:149-57.
Piper MC, Pinnell LE, Darrah J, Maguire T, Byrne PJ. Construction and validation of theAlberta Infant Motor Scale (AIMS). Can J Public Health 1992;83(Suppl 2):S46-50.
Bayley N. Manual for the Bayley scales of infant and toddler development.3rd edn.
Psychological Corporation, 2006.
Van der Ploeg HM, Defares PB, Spielberger CD. Handleiding bij de Zelf-Beoordelings
Vragenlijst, ZBV: Een Nederlandstalige bewerking van de Spielberger state-trait anxiety
inventory. Swets & Zeitlinger, 1980.
Landgraf JM, Vogel I, Oostenbrink R, van Baar ME, Raat H. Parent-reported healthoutcomes in infants/toddlers: measurement properties and clinical validity of the
ITQOL-SF47. Qual Life Res 2013;22:635-46.
Mindell JA, Kuhn B, Lewin DS, Meltzer LJ, Sadeh A. Behavioral treatment of bedtime
problems and night wakings in infants and young children. Sleep 2006;29:1263-76.
Harth SC, Thong YH. Sociodemographic and motivational characteristics of parents who
volunteer their children for clinical research: a controlled study. BMJ 1990;300:1372-5.
Rovers MM, Straatman H, Ingels K, van der Wilt GJ, van den Broek P, Zielhuis GA.
Generalizability of trial results based on randomized versus nonrandomized allocation of
OME infants to ventilation tubes or watchful waiting. J Clin Epidemiol 2001;54:789-94.
Nuysink J, Eijsermans MJ, van Haastert IC, Koopman-Esseboom C, Helders PJ, de Vries
LS, et al. Clinical course of asymmetric motor performance and deformational plagiocephaly
in very preterm infants. J Pediatr 2013;163:658-65 e1.
Bialocerkowski AE, Vladusic SL, Howell SM. Conservative interventions for positional
plagiocephaly: a systematic review. Dev Med Child Neurol 2005;47:563-70.
Wilbrand JF, Wilbrand M, Malik CY, Howaldt HP, Streckbein P, Schaaf H, et al.
Complications in helmet therapy. J Craniomaxillofac Surg 2012;40:341-6.
Feijen M, Schuckman M, Habets E, van der Hulst R. Positional plagiocephaly andbrachycephaly: is there a correlation between subjective and objective assessment of
cranial shape? J Craniofac Surg 2012;23:998-1001.
Katzel EB, Koltz PF, Sbitany H, Emerson C, Girotto JA. Real versus perceived
improvements of helmet molding therapy for the treatment of plagiocephaly. Plast Reconstr
Surg 2010;126:19e-21e.
Suarez-Almazor ME, Conner-Spady B, Kendall CJ, Russell AS, Skeith K. Lack ofcongruence in the ratings of patients’ health status by patients and their physicians. Med
Decis Making 2001;21:113-21.
Van der Ploeg CBP, Van Wijk RM, van den Akker EM, Boere-Boonekamp MM. Cost
assessment of helmet treatment compared to natural course in infants with skull
deformation. TNO, 2013.
Hutchison BL, Hutchison LA, Thompson JM, Mitchell EA. Quantification of plagiocephaly
and brachycephaly in infants using a digital photographic technique. Cleft Palate Craniofac
J 2005;42:539-47.

Accepted: 29 March 2014
Cite this as: BMJ 2014;348:g2741
This is an Open Access article distributed in accordance with the Creative Commons
Attribution Non Commercial (CC BY-NC 3.0) license, which permits others to distribute,
remix, adapt, build upon this work non-commercially, and license their derivative works
on different terms, provided the original work is properly cited and the use isnon-commercial. See: http://creativecommons.org/licenses/by-nc/3.0/.

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Positional skull deformation is common in infancy

BMJ 2014;348:g2741 doi: 10.1136/bmj.g2741 (Published 1 May 2014)

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TablesCharacteristics

Total population (n=84)

Helmet therapy (n=42)

Natural course (n=42)

Boys

61/84 (73)32/42 (76)29/42 (69)

Mean (SD) age at baseline (months)

5.1 (0.4)

5.1 (0.4)

5.1 (0.3)

Mean (SD) age at follow-up (months)

24.8 (4.4)

25.0 (3.5)

24.6 (5.1)
19/39 (49)Birth rank (first born)

39/79 (49)

20/40 (50)

Health problems†

6/84 (7)4/42 (10)

2/40 (5)Ethnicity (ethnic minority)‡

5/77 (7)4/41 (10)

1/36 (3)Education level of parents§:
Low

24/81 (30)

15/42 (36)

9/39 (23)Medium34/81 (42)15/42 (36)

19/39 (49)High

23/81 (28)

12/42 (29)

11/39 (28)

Numbers may not add up to group totals because of missing data.
2*Groups compared using t test or χ test.
†Problems with sight, hearing, oesophageal reflux, developmental dysplasia of hip, congenital heart disease, or inguinal hernia.
‡At least one parent born outside of the Netherlands.
§Low education level: lower technical and vocational training and lower general secondary education; medium education level: intermediate vocational training
and advanced secondary education; and high education level: higher vocational education and university. Percentages may not total 100%, due to rounding off.

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Table 1| Characteristics of study population of infants with skull deformation. Values are numbers (percentages)* unless stated otherwise

BMJ 2014;348:g2741 doi: 10.1136/bmj.g2741 (Published 1 May 2014)

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Table 2| Baseline clinical characteristics of study population at age 5 months. Values are means (standard deviations) unless statedotherwise*
Helmet therapy (n=42)

Natural course (n=42)

Plagiocephaly (ODDI)†

107.2 (3.9)

109.2 (2.9)

Brachycephaly (CPI)†

93.4 (6.9)

90.3 (6.2)

Ear deviation (EDI)

4.7 (3.5)

5.5 (3.0)

No (%) with facial asymmetry

7 (17)

13 (31)

No (%) with occipital lift

18 (43)10 (24)Motor development (AIMS Z-score)−0.7 (1.0)−0.7 (1.0)

Parental satisfaction

2.8 (0.8)

3.0 (1.0)

State anxiety (STAI-DY)

30.8 (7.1)

32.2 (8.6)

ODDI=oblique diameter difference index (value of 100% represents purely symmetrical head shape, value >100 represents asymmetrical skull deformation; thehigher the score, the more severe the deformation); CPI=cranioproportional index (score of 80% represents an average head shape in Western countries, higher
value represents a larger head width compared with length); EDI=ear deviation index (value of 0 represents no ear deviation; the higher the score above 0, themore severe the ear deviation). AIMS=Alberta infant motor scale standardised Z scores (individual score minus average score divided by standard deviation);
STAI-DY=Dutch version of Spielberger state-trait anxiety inventory (scores range from 20 to 80; a higher score represents a higher state anxiety).
2*Groups compared using t test or χ test.
†P<0.05.

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Clinical characteristics

BMJ 2014;348:g2741 doi: 10.1136/bmj.g2741 (Published 1 May 2014)

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Table 3| Primary outcomes, measured at 24 months. Values are means (standard deviations) unless stated otherwise

Helmet therapy (n=39)

Natural course (n=40)

Plagiocephaly change score‡

2.9 (2.9)

3.1 (3.3)

0.80

3.4 ( 2.6 to 4.2)

2.6 (1.8 to 3.4)

0.13

Brachycephaly change score§

7.0 (4.1)

6.8 (4.4)

0.81

6.4 (5.3 to 7.5)

7.4 (6.4 to 8.5)

0.20

No (%) with full recovery¶

10 (26)9 (23)

0.74

**

**

**

ANCOVA=analysis of covariance.

P value* Helmet therapy Natural course

P value

2*Groups compared using t test or χ test.
†ANCOVA model with baseline measurement at age 5 months as covariate.
‡Oblique diameter difference index at age 5 months minus at age 24 months.
§Cranioproportional index at age 5 months minus at age 24 months.
¶Oblique diameter difference index <104% and cranioproportional index <90%.
**Not analysed because of low number of cases.

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ANCOVA; adjusted means (95% CI)†
Outcomes

BMJ 2014;348:g2741 doi: 10.1136/bmj.g2741 (Published 1 May 2014)

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Table 4| Secondary outcomes, measured at age 24 months. Values are means (standard deviations) unless stated otherwise
Helmet therapy (n=39)

Natural course (n=40)

P value*

Helmet therapy−natural course

Ear deviation change score (n=79)†

2.0 (4.0)

1.9 (3.6)

0.86

0.2 (−1.5 to 1.8)

No (%) with facial asymmetry

5/38 (13)

10/39 (26)0.17

0.4 (0.1 to 1.4)‡
2.2 (0.4 to 13.0)‡

No (%) with occipital lift

4/38 (11)2/40 (5)0.36

Parental satisfaction (n=77)

4.6 (0.5)

4.4 (0,6)

0.06

0.2 (−0.1 to 0.5)

State anxiety (STAI-DY) (n=76)

27.4 (6.5)

31.3 (9.2)

0.04−3.9 (−7.5 to −0.2)

BSID-III composite score (n=77)

97.2 (9.4)

99.0 (11.6)

0.17−1.8 (−6.6 to 3.0)

BSID-III fine scale (n=78)

10.0 (1.9)

10.8 (2.2)

0.21−0.7 (−1.7 to 0.2)

BSID-III gross scale (n=78)

9.1 (1.8)

8.8 (2.4)

0.58

0.2 (−0.7 to 1.2)

STAI-DY=Dutch version of Spielberger state-trait anxiety inventory (scores range from 20 to 80; a higher score represents a higher state anxiety); BSID III=Bayley
scales of infant and toddler development, third edition (standardised motor composite scores mean 100 (SD 15), scaled scores for fine and gross motor development
mean 10 (SD 3).

2*Groups compared using t test or χ test.
†Ear deviation index measurement at age 5 months minus at age 24 months.
‡Odds ratio (95% confidence interval).

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Secondary outcomesBMJ 2014;348:g2741 doi: 10.1136/bmj.g2741 (Published 1 May 2014)

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Figures
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Fig 1 Flowchart of HElmet therapy Assessment in Deformed Skulls study

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RESEARCH

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Fig 2 Plagiocephalometry and cut-off points for severity of skull deformation. Illustration shows left occipital flattening ofskull and thermoplastic measuring ring with digitally drawn lines used in plagiocephalometry. Indices were calculated by
the following formulas: cranioproportional index, sinistra-dextra/anterior-posterior×100%; oblique diameter difference index,
longest oblique diameter/shortest oblique diameter×100%; and ear deviation index, ear deviation/anterior-posterior×100%