JOINING FORCES

Joining Families

Volume 18, Issue 3 • Fall 2019

R E A L W O R L D R E S E A R C H F O R F A M I LY A D V O C A C Y P R O G R A M S
F E AT U R E D I N T E R V I E W

Development and Validation of an Evidence-Based
Procedure for Evaluation of Abusive Head Trauma in
Young Children
Interview with Kent P. Hymel, MD
Kent P. Hymel, MD

Kent P. Hymel, MD, is Professor of Pediatrics at the Penn State College of Medicine. He
completed a fellowship in Child Abuse Pediatrics
at The Children’s Hospital, Denver, Colorado in
1996. He served as the U.S. Air Force Medical
Consultant for Child Abuse, and has directed
In This Issue
The subject of this JFJF is head trauma related to infant/child abuse,sometimes in the past referred to as “shaken baby syndrome,” but moreaccurately now called abusive head trauma (AHT). We present an interview
with Kent P. Hymel, MD, a pediatrician specialized in child abuse. He isProfessor, Department of Pediatrics, Penn State College of Medicine, Penn
State Health Children’s Hospital, Hershey, PA. The interview describes what
constitutes AHT: the mechanisms of injury, his research on developing anevidence-based screening tool for physician use in order to minimize missed
cases of AHT, and a procedure for estimating the probability that a headinjured child has been abused based on the outcome of the medical workup.
Additional articles supplement Dr. Hymel’s interview by providing informationon the incidence of AHT, clinical findings, outcomes, and programs to prevent
AHT in young children. Our statistics article gives descriptions of sensitivity
and specificity, which are used in developing screening tools. Websites ofInterest includes Dr. Hymel’s research network, the PediBIRN, as well as othersources of information on AHT for clinicians, caregivers, and educators.

Contents

Development and Validation of an Evidence-Based Procedure for Evaluationof Abusive Head Trauma in Young Children………………………………… 1
Abusive Head Trauma in Young Children: Definition, Clinical Findings,
Mechanisms of Injury, and Outcomes……………………………………… 5
Prevention of Abusive Head Trauma in Infants……………………………… 7
Sensitivity and Specificity: Two Statistical Measures Used in Tests
Screening for Disease ……………………………………………………… 9
Websites of Interest……………………………………………………… 12child abuse programs at Inova Fairfax Hospitalfor Children and the Dartmouth Hitchcock Medical Center. In 2014, Dr. Hymel joined the Centerfor the Protection of Children at Penn State
Hershey Medical Center. He is a past member ofthe American Academy of Pediatrics’ Committee
on Child Abuse and Neglect, a past President of
the Ray E. Helfer Society (the professional society
for physicians specialized in child abuse), andwas the Deputy Medical Editor of the Subboard
in Child Abuse Pediatrics of the American Boardof Pediatrics. Much of his career has been devoted
to research on the objective diagnosis of pediatric abusive head trauma. Dr. Hymel founded
and directs the Pediatric Brain Injury Research
Network (PediBIRN), and is the Principle Investigator of an NIH-funded clinical trial testing theimpact of a novel, Pediatric Intensive Care Unit
(PICU)-based screening tool for pediatric AHT.
He has a wide variety of medical publications
on the pathophysiology of traumatic intracranial
hemorrhage, the timing of its clinical signs, andrelated topics such as race and ethnic disparities
and biases in the evaluation and reporting ofsuspected head-injured children.

Dr. McCarroll: Abusive head trauma (AHT) isa major cause of death of abused infants andyoung children. Over half of the 600 deaths ofchildren under age five who were reported to
the National Violent Death Reporting System
during 2003–2006 were due to AHT (Klevens
Continued on page 2

An interview with Kent P.
Hymel, MD, from page 1

When someone acts
spontaneously it ismore likely that theywould strike or throwa baby rather thanpick them up andshake them.

& Leeb, 2010). This is an alarming statistic
and a topic of medical and social concern.
What would a physician in an emergency
department see in a child admitted for headtrauma?
Dr. Hymel: There is a big variety. Not every
head trauma is inflicted. However, most simple
falls and indoor accidental traumas that the
average ambulatory child experiences, do not
end up in an ICU. Most children with headtrauma, whether it is inflicted or accidental, present for urgent care to an emergency
department. When the severity of the injury
is recognized — such as by a life-threatening
clinical sign like seizures, respiratory compromise, shock, or unconsciousness — the childis stabilized and transported to the nearest
regional intensive care unit or a pediatricICU (PICU). These are places where pediatricsurgeons and neurosurgeons are available. In
the most severe cases, these children present
as unresponsive with respiratory compromiseand may have stopped breathing. Those are thechildren that frequently do not survive. If they
do survive, they often have major brain injuries. When you stop breathing or you go into
shock your brain is not receiving oxygen andthe negative impacts begin pretty quickly.
Dr. McCarroll: A term that we commonly see
in child abuse literature is “shaken baby
syndrome.”

JOINING FORCES
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Joining Forces Joining
Families is a publication of
the Center for the Study ofTraumatic Stress (CSTS)
and the U.S. Army Installation Management Command. The CSTS is part of
the Department of Psychiatry, Uniformed Services
University (USU), Bethesda,
MD 20814. The USU is the
US national federal military
medical school.

Editor-in-Chief
James E. McCarroll, PhD
Email: James.McCarroll.ctr@usuhs.edu
Editors
Joshua C. Morganstein, MD
Captain, US Public Health Service
Assistant Director, CSTS
Associate Professor and Assistant Chair
Department of Psychiatry, USU
Ronald J. Whalen, PhD, LMSW
Research Social Worker, CSTS
Research Assistant Professor
Department of Psychiatry, USU
Assistants to the Editors
Alexandra Burris, BA
Britany Mullins-Hussain, BA

Dr. Hymel: Shaken baby syndrome wasa term used in the past to describe children
whose head trauma was believed to have resulted from violent shaking. Most of us prefer
the term abusive head trauma or AHT. There
are often other injuries in addition to shaking
that these children experience. There have been
individuals who have implied that changing terminology from shaken baby to AHT means that
we no longer believe violent shaking is dangerous. I think that is wrong. The overwhelming
majority of practicing physicians believe thatshaking an infant is clearly dangerous and precipitates the constellation of findings that would
be labeled as abusive. I do not recall a childover one year old where I had concluded thatthe child had experienced only shaking. Whensomeone acts spontaneously it is more likelythat they would strike or throw a baby rather
than pick them up and shake them.
Dr. McCarroll: At what age does child shaking
tend to occur?
Dr. Hymel: The peak age of AHT correlates well with the peak age of crying, four-tofive-months of age. Its frequency drops after
six-to-nine months. Babies are hard to shake
when they get heavy. It is less likely that babies
older than nine or twelve months are shaken.
Violent shaking is a mechanism that somechildren experience, but many also experiencean impact that contributes to their injury. For
the overwhelming majority of children, we findevidence of impact.
The brain is protected from impacts because
it is enclosed in the skull and is suspended in alayer of water-like fluid, cerebrospinal fluid. So,
it floats. That helps decrease injury if the headexperiences an impact. But if the head is put
into rotational motion, substantial damage occurs. With that, brain tissues of different density
are moving at different rates, shearing. In shaking, because the head is tethered to the body by
the neck, shaking typically causes a whiplash,arc-like motion. Let’s say shaking has put thehead in violent motion and it is now moving
forward towards the chest. As the skull moves
forward, the brain lags behind because it is not
rigid and you can imagine that the brain begins
to catch up and it is moving forward as well. But
then, the chin hits the chest, the skull abruptly
stops, and the brain continues to move forward
until it impacts the inner surfaces of the front of
the skull and the base of the skull and it stops.
Continued on p. 3

2 • Joining Forces/Joining Families

Fall 2019

An interview with Kent P.
Hymel, MD, from page 2

Any one of four
variables can identify
which children need athorough workup forabuse: (1) bleeding
overlying the brain(subdural hematoma),(2) respiratorycompromise before
hospital admission,(3) any bruising of thetorso, ears, or neck (4)and a complex skull
fracture.

This is where the brain interfaces with the morerigid structures of the skull and we expect thedamage to occur.
Dr. McCarroll: Can you distinguish themechanism of injury, shaking versus blunttrauma?
Dr. Hymel: Yes. That is also interesting.
Closed head trauma can occur from an impact
or from a whiplash-like mechanism. So, there
are three possible mechanisms of injury. By
interpreting the findings in the context of whatmust have happened to the head, we can begin
to get an idea of what the child experienced:
isolated impact that did not cause significant
head motion; severe head motion in isolation;
or a combination of the two. The vast majorityof children have suffered impact sufficient to
put their head into violent motion.
Dr. McCarroll: Do you see other injuries in
addition to head injuries across a wide rangeof children’s ages?
Dr. Hymel: Yes. We do see non-cranial
injuries in babies who also have head injuries
from abuse. It is not uncommon to see fractures and abdominal injuries. The appropriate
workup once we have been convinced thata child has suffered physical abuse is to lookthoroughly for injuries. If we suspect abuse in ayoung child, we get a number of tests including
head imaging studies and lab tests to screen for
abdominal trauma such as liver injury. They
will also often have urine tests to look for bloodthat might suggest kidney injury.
Dr. McCarroll: What about damage to thenerves in the brain, axonal damage? Does
that also occur?
Dr. Hymel: In fatal cases, forensic neuropathologists can look microscopically forevidence of nerve damage. Patterns of axonal
injury can provide information about mechanisms of injury, but it is only useful in fatal
cases. There are some CT findings that areoccasionally seen that have been associatedwith those microscopic finding at autopsy. But
in general, it is only found in fatal cases. It isa pretty ominous finding. If they survive theyalmost certainly will have moderate or severe
deficits, more likely severe.
Dr. McCarroll: There are many complex
medical and social issues associated withthe decision to evaluate a child for AHT. I
was surprised at the degree of controversy in

http://www.CSTSonline.org

the literature. I thought that if trauma occurs,that you push on with the evaluation and dowhat you can. How is it that cases of AHT are
missed?
Dr. Hymel: It sometimes is baffling to me
that physicians who are caring for a child withobvious trauma to the head, with findings ofsevere brain injury and bleeding overlying
the brain, hear a story that it was caused by asimple fall and somehow accept it as valid. If
we have children or have been around children
or grandchildren, they fall all the time once
they learn to walk and yet they do not end up
in intensive care units. There are lots of reasons
why doctors suspect, but fail to report abuse. It
is not only a failure to recognize the signs andsymptoms, it is more than that. It can be an
unwillingness to consider or make the diagnosis, a fear of making an erroneous diagnosis, ora fear of being wrong. To some degree, it canalso be a fear of courtroom testimony and allof the other aspects of engagement with childprotective services, police investigators, lawyers,and eventually testifying. In addition, there isa small, but ardent group of defense attorneys
and their medical experts who testify frequently
for the defense. These are individuals who argue
that AHT does not exist or occurs only very
rarely. (See Leventhal & Edwards, 2010 for a
discussion of these issues.)
Physicians may also be hesitant to reportsuspected abuse if they know the family because they do not want to jeopardize their relationship with the family. There is also evidence
that some doctors’ practice with bias (Hymel
et al., 2018). We tend to look for the diagnosis
where we suspect we will find it. We tend to
not look for the diagnosis in families and cases
where we do not expect to find it. We tend toevaluate more children with head trauma whocome from minority race/ethnicity families andhave only a single adult caregiver in the homeor who are on the lower end of the socioeconomic spectrum. Doctors tend to less frequently evaluate equivalent children if they are froma white family with two parents and a higher
socioeconomic status. It is a clarion call that weneed unbiased assessment tools. We need tests
to better inform consistent decisions that will
move us beyond race and socioeconomic status
and guessing that can give clear guidance as towhen a head-injured child should be evaluatedfor abuse.
Dr. McCarroll: As I understand the backgroundContinued on p.4
Joining Forces/Joining Families • 3

An interview with Kent P.
Hymel, MD, from page 3

One type of clinicalprediction rule is basedon statistical estimatesof probability. Everyfinding, every test
result, every lab result
has a predictive value.
For every test you canimagine, every finding,
you can measure its
predictive contribution
as positive or negative.

of your research, it is based on the factthat there are a lot of cases of AHT coming
into pediatric PICUs that are missed. Your
research is directed toward providing
physicians with decision rules to help guidedeciding whether to perform an extensive
evaluation of a head-injured child for abuse
and whether to subsequently report them forchild physical abuse. You have developed two
clinical prediction rules. Would you explain
those?
Dr. Hymel: The purpose of the first rule is
to identify which acutely head-injured children
presenting to intensive care settings should be
evaluated immediately for AHT. This is a fourvariable rule that informs doctors that an abuse
evaluation should be performed if any oneof four variables is positive during the initial
examination (see fuller discussion of four-variable rule below and “Abusive Head Trauma in
Young Children: Definition, Clinical Findings,
Mechanism of Injury, and Outcomes” summary in this edition of JFJF). The second rule
is for doctors to use after the abuse evaluation
has been completed to inform their decision toconfirm, exclude and/or report suspected childabusive head trauma — child abuse. The latter
rule (the PediBIRN-7) estimates the probability
that a head-injured child was physically abused
based on seven variables that were evaluated.
Dr. McCarroll: How did you become interested
in this research?
Dr. Hymel: My interest began one day
when I was in training to become a child abuse
pediatrician. My mentor, Dr. Carole Jenny,
walked into the conference room in the clinic
where we were seeing patients and she threw
a stack of records down on the table. She said
that the medical system screwed this child.
The child almost certainly had suffered abusive
head trauma at the age of four months. Now
the child was being seen again at 11 months
old for a new injury with multiple new andhealing fractures. No one diagnosed abusive
head trauma. Right then and there she decided
that we were going to do a study of missed
cases of abuse. She invited me to help. (See
Jenny, Hymel, Ritzen, Reinert, & Hay, 1999.)
The case that Dr. Jenny presented never left
me. For years I thought about how we could
lessen the number of missed cases and improve
the accuracy of doctors’ decisions to workup or
not workup head injured kids for abuse. I had
a conversation with another doctor who asked
me about my research. When I told him what I

4 • Joining Forces/Joining Families

wished I could do, he said, “You need a clinicalprediction rule.” One type of clinical prediction
rule is based on statistical estimates of probability. Every finding, every test result, every lab
result has a predictive value. For every test you
can imagine, every finding, you can measure its
predictive contribution as positive or negative.
Some tests end up being most useful when they
are part of a screening tool because they cast a
broad net. In other words, a high percentageof the kids with the diagnosis will have thatfinding. Other results are more useful to be
included in diagnostic tests because they are
only positive when you have that diagnosis. We
captured data from both laboratory tests andradiological findings that we thought might beuseful in making a diagnosis and, more specifically, might contribute to a screening tool. My
goal was not to miss cases. We captured thedata across 14 sites where children were evaluated for AHT and identified which variables
were reliable. To create a screening tool, I only
need to consider variables that are available
at the time of hospital admission in order toinform doctors’ early decision of whether or
not to launch an abuse evaluation. Based on
our analyses, we discovered that four variables
were pretty darn good at identifying whichchildren needed a thorough workup for abuse.
These four variables were (1) bleeding overlying
the brain (subdural hematoma), (2) respiratorycompromise before hospital admission, (3) any
bruising of the torso, ears, or neck (4) and acomplex skull fracture (Hymel et al., 2014). We
found that 96% of the cases later categorized asabuse based had one or more of those four predictor variables. Our clinical rule then becamea directive rule: If your patient with closed headtrauma under the age of three is admitted andpresents with any one or more of these fourthings, you should consider them higher risk
and we recommend a thorough workup.
Dr. McCarroll: Your research has been
conducted with investigators in the PediatricBrain Injury Research Network (PediBIRN), agroup in which 18 pediatric sites around theUnited States and Canada have participated.
Can you lead us through your thinking on thedevelopment of the clinical prediction andclinical decision rules and then tell us where
your research is now?
Dr. Hymel: Yes. Whenever a clinical prediction rule is developed there is an expectedtrajectory of research. You first have to do aContinued on p. 10
Fall 2019Abusive Head Trauma in Young Children:
Definition, Clinical Findings, Mechanisms of Injury,
and Outcomes
By James E. McCarroll, PhD, Joshua C. Morganstein, MD, Ronald J. Whalen, PhD
and Robert J. Ursano, MD
The youngest infants(under six months) are
the most vulnerable
as AHT is commonly
triggered by infantcrying. Parents may
also shake children
under two years ofage as a method of
discipline.

http://www.CSTSonline.org

Background. Caffey was the first to use
the term “whiplash shaken infant syndrome”(Caffey, 1974). Shaken baby syndrome (SBS)
has, since Caffey, been the term used in medical literature and in popular publications. It
has also been the term used in prevention
programs (see Websites of Interest). The.
American Academy of Pediatrics (AAP) has
proposed to change the terminology from SBS
to abusive head trauma (AHT), away from themechanism of injury (shaking) and toward theclinical findings (head trauma) (Christian &Block, 2009). SBS is still a recognized diagnosis(S. K. Narang, Estrada, Greenberg, & Lindberg,
2016; Strouse, 2018). SBS is a useful concept for
medical and social service providers to educate
children’s caregivers about the importance ofnever shaking an infant. However, shaking frequently includes other injuries. In addition to
shaking, which produces an injury due to rotation of the head, brain, eyes, and spine, there
are other injury mechanisms including injuries
from slamming, striking with an object, throwing, and crush forces (Greeley, 2015).
Definition and Costs. The AAP definitionof AHT is any injury intentionally inflicted on
the head or brain of a child (Christian & Block,2009). Regardless of severity, the medical,
surgical, and social costs of AHT of children
can be enormous. More than 40% of children
with AHT are severely injured. It is estimatedthat one in 14 cases admitted for severe AHT
will die before hospital discharge. Children
who survive AHT will have health care costs
that can last for their lifetime. Even those witha mild case have an estimated loss of 15.5% of
their health-related quality of life and a cost ofover $1million. (Quality of life costs include
lost work time and costs associated with personal care.) Costs for those with severe AHT
can exceed $3 million (Miller et al., 2018).
Incidence. A recent extensive review of
infant and child head trauma described its incidence, clinical findings, secondary injuries, andoutcomes (Greeley, 2015). The youngest infants(under six months) are the most vulnerable as

AHT is commonly triggered by infant crying.
Parents may also shake children under two
years of age as a method of discipline. Male
children are slightly more likely to be abusedwith fathers being the most common perpetrators, followed by boyfriends and female babysitters. There are many difficulties in estimating
the incidence of AHT: abused infants may not
be taken for medical care; medical providers
may not recognize AHT as symptoms can bemisinterpreted in young children; there aredisagreements among doctors about whether
to and how to evaluate symptoms; and caregivers may avoid giving an accurate history of thechild’s injuries.
Clinical Findings. The clinical picture mostoften seen includes injuries to the skull andcentral nervous system and subdural hematoma (bleeding overlying the brain). There canalso be bruising and swelling of the skin, longbone and rib fractures, injuries to the neck,and bleeding in the eye and the retinal nerve.
Symptoms and signs of the injury usually appear in seconds or minutes and can include
vomiting, altered mental status, seizures, andapnea (disturbance or stoppage of breathing)(Greeley, 2015).
Evaluation and Mechanisms of Injury. The
clinical findings are most informative when
they occur in combination. The combinationof clinical findings and their association with
AHT is at the core of Dr. Hymel’s research. Dr.
Hymel’s clinical approach for physicians to use
to evaluate AHT indicates that AHT should be
evaluated in a child presenting for medical carewhen any one of the following is observed: subdural hematoma, retinal bleeding, respiratorycompromise before hospital admission, or any
bruising of the torso, ears, or neck (Hymel et al.,2014). Two mechanisms of axonal injury havebeen described. In the first, there is immediate
traumatic injury. The main mechanism of damage to the brain is immediate physical injury to
the nerves (Fitzpatrick, Maxwell, & Graham,
1998). The second mechanism consists of delayed effects of nerve damage (Adams, Graham,
Joining Forces/Joining Families • 5

Abusive Head Trauma in
Young Children, from page 5

Shaking can produce
an injury due to rotationof the head, brain,eyes, and spine. Other
possible injuries canresult from slamming,
striking with an object,
throwing, and crush
forces.

S., & Scott, 1982). These delayed effects canresult in brain swelling, decreased blood flow,
and hypoxia, all of which may contribute toneuronal death. (Greeley, 2015).
Outcomes. AHT is a common cause ofdeath from child traumatic maltreatment
accounting for 80% of all deaths from nonaccidental trauma (Paul & Adamo, 2014) andan estimated incidence of 16 to 33 cases per
100,000 children per year in the first 2 years oflife (Narang & Clarke, 2014). Estimates are that
8-25% of victims of AHT die from their injuries and that the survivors typically have severe
disabilities. A Canadian study of 364 cases of
shaken baby syndrome reported to pediatrictertiary care hospitals in 1988-1998 foundabout 60% had a moderate or greater degree of
disability of neurologic function, 65% had visual impairment, and 12% were in a permanent
vegetative state. Only 7% were reported to havenormal neurologic function. The median age ofchild victims was 4.6 months; 56% were boys
(King, MacKay, & Sirnick, 2003). A prospective
study of 56 cases in Switzerland from 20022007 found that 64% of AHT victims weredisabled and 36% had a good outcome after 13
months. The preponderance of victims weremales (63%) and the median age was 4 months(Fanconi & Lips, 2010).
Conclusions. Authors from a variety of
medical fields have emphasized the enormous
effects of AHT on children, families and othercaregivers, medical providers, and even thelegal systems, which have to judge the circumstances of these injuries to children. The
diagnosis of AHT can be a difficult clinicaldecision. The clinical presentation includes
diverse findings that may be non-specific oreven unnoticed. It is the presence of one ormore specific clinical findings in head-injured
children that should lead to a complete evaluation (Hymel et al., 2014) and a later decision
based on clinical findings about whether thetrauma to head-injured children is due to childabuse (Hymel et al., 2019).

6 • Joining Forces/Joining Families

References

Caffey J. (1974). The whiplash shaken infant syndrome. Pediatrics, 54, 396-403.
Christian W, & Block R. (2009). Abusive headtrauma in infants and children. Pediatrics;
123(5): 1409-1411.
Fanconi M, & Lips U. (2010). Shaken baby syndrome in Switzerland: results of a prospective
follow-up study. European Journal of Paediatrics; 169(8): 1023-1028.
Greeley CS. (2015). Abusive head trauma: A
review of the evidence base. American Journalof Roentgenology; 204(5): 967-973.
Hymel KP, Armijo-Garcia V, Foster R, Frazier
TN, Stoiko M, Christie LM, . . . (PediBIRN).
(2014). Validation of a clinical prediction rule
for pediatric abusive head trauma. Pediatrics;
134(6): e1537-e1544.
Hymel KP, Wang, M., Chinchilli VM, Karst W A,
Willson DF, Dias MS,… (PediBIRN). (2019).
Estimating the probability of abusive headtrauma after abuse evaluation. Child Abuse &Neglect; 88: 266-274.
King WJ, MacKay M, & Sirnick A. (2003). Shaken
baby syndrome in Canada: clinical characteristics and outcome of hospital cases. Canadian
Medical Association Journal; 168(2): 155-159.
Miller TR, Steinbeigle R, Lawrence BA, Peterson
C, Florence C, Barr M, & Barr RG. (2018).
Lifetime cost of abusive head trauma at ages
0-4, USA. Prevention Science; 19(6): 695-704.
Narang SK, Estrada C, Greenberg S, & Lindberg DM. (2016). Acceptance of shaken baby
syndrome and abusive head trauma as medical
diagnoses. Journal of Pediatrics; 177: 273-278.
Paul R, & Adamo MA. (2014). Non-accidental
trauma in pediatric patients: a review of epidemiology, pathophysiology, diagnosis and treatment. Translational Pediatrics; 3(3): 195-207.
https://www.ncbi.nlm.nih.gov/pmc/articles/
PMC4729847/
Strouse PJ. (2018). Shaken baby syndrome is real.
Pediatric Radiology; 48(8): 1043-1047.

Fall 2019

Prevention of Abusive Head Trauma in Infants
By James E. McCarroll, PhD, Joshua C. Morganstein, MD, Ronald J. Whalen, PhD
and Robert J. Ursano, MD

Most AHT is due
to parents’ or
caregivers’ responses
to prolonged,
unsoothable infantcrying during thefirst months of life.
The infant’s crying
can be interpreted
as something wrong
with the infant rather
than recognizing it
as part of normal
development.

http://www.CSTSonline.org

Abusive head trauma (AHT) is a form ofchild abuse that is a significant cause of childdeath and disability. About two-thirds of 1,374
child maltreatment fatalities in children underage five that were reported to the National
Violence Death Reporting System (NVDRS),
2003-2006, were due to AHT (Klevens & Leeb,2010). Homicide was the second leading causeof violence-related injury deaths for children
under one year of age and the third leading cause for children 1-4 in the U.S. in 2017https://www.cdc.gov/injury/images/lc-charts/
leading_causes_of_death_by_age_group_
violence_2017_1100w850h.jpg. These reports
are known to be underestimates (Klevens &Leeb, 2010; Reese, Heiden, Kim, & Yang, 2014).
Of the head-injured children that survive theirabuse, most are likely to suffer temporary or
permanent disability (Fanconi & Lips, 2010;
King et al., 2003).
Most AHT is due to parents’ or caregivers’
responses to prolonged, unsoothable infantcrying during the first months of life (Barr,
Rajabali, Aragon, Colbourne, & Brant, 2015;
Barr, Trent, & Cross, 2006). In addition tocaregiver frustration, the infant’s crying canbe interpreted as something wrong with theinfant rather than recognizing it as part ofnormal development (Barr, 2012). Given theseriousness of AHT, many preventive programs
have been put into effect and evaluated. In areview of 35 articles on AHT prevention, three
categories of AHT-prevention initiatives were
found: (1) efforts to reduce infant crying in thefirst few months of life, (2) emotional regulation strategies for caregivers, and (3) raisingawareness of AHT (Lopes & Williams, 2018).
The conclusion of this review was that raisingawareness by educating parents and caregiverson the pattern of infant crying and the risks ofshaking a baby was the best strategy. Educational strategies have lower costs and ease of
implementation compared to reducing infantcrying and emotional regulation strategies. Attempts to reduce infant crying and emotional
regulation strategies require longer intervention times and specialized training of healthprofessionals, both of which are impractical forlarge-scale application.
The prevention of AHT is an excellent
target for primary prevention: (1) the outcomesare severe and financially costly, (2) AHT has
clear risk behavior (shaking) and a stimulus(crying), and (3) evidence is emerging that it ispreventable. In addition, it needs to be primary(delivered before AHT occurs). It also needs
to be universal in that all new parents should
receive training. Furthermore, messaging
and training should be attractive, consistent,
meaningful, and positive for many different
cultures. It should be delivered to all parents ofnewborns, not just “at risk” parents and caregivers since AHT can occur in the absence of risk
factors (Barr, 2012).
An SBS prevention program that hasreceived extensive worldwide application andevaluation is the Period of Purple Crying (seeWebsites of Interest). There are many reasons
why babies cry, but this program refers to thecrying that is specifically associated with colic.
The causes are unknown, but it is a normal
phase of child development. Three steps aresuggested to deal with infant crying: 1) holding
and walking with the baby, (2) placing the baby
in a safe place and walking away for a few minutes, and (3) never shaking or harming the baby
(Lopes & Williams, 2018). A randomized trialof educational materials designed to change
behavior and increase knowledge regarding
crying and SBS found significant increases inknowledge regarding infant crying patterns,
risks of shaking an infant, and sharing information with other caregivers about the importanceof walking away when frustrated with thecrying. However, this study was not sufficiently
large to test whether the Period of Purple
intervention prevents SBS (Barr et al., 2009). It
is also important to inform transient caregivers
such as baby sitters, parents’ partners, and otherfamily members about infant crying. Transient
caregivers may interpret crying as a failure on
their part to provide good care and may resort
to shaking to stop it (Barr, 2012)
An evaluation of the Period of Purple Crying was conducted in five birthing hospitals in
a Midwest city in 2011 as part of a state-wide
mandate to provide voluntary AHT prevention
programs to caregivers of infants and young
children (Reese et al., 2014). The program wasdelivered in person by nurses to 211 mothersprior to discharge. The program was evaluatedContinued on page 8
Joining Forces/Joining Families • 7

Prevention of Abusive Head
Trauma in Infants,from page 7

Three steps to deal
with infant crying
are: (1) holding andwalking with thebaby, (2) placing thebaby in a safe place
and walking away fora few minutes, and(3) never shaking or
harming the baby.

in a non-experimental post-only design after
the program was delivered in the hospital andfollowed up two months later. The study measures included attitudes about the education
session and AHT, knowledge about crying andshaking a baby, techniques for coping with infant crying, and intent to share the information
with another care provider. Nurses reported
feeling comfortable delivering the program.
Seventy-six percent of the mothers rated theprogram as very useful. However, despite
the high ratings of the program, only 41% of
mothers shared the content with their infant’s
other care providers. One of the reasons given
for this were that the mothers thought there
was a low perceived risk for shaking by theirchildren’s caregivers. However, the majority of
AHT-perpetrators are not mothers. In a review
of 459 AHT-injured children, 53% were fathers, 22% were parent partner, 8% were mothers, 8% were baby-sitters, and 5% were another
adult caregiver (Scribano, Makoroff, Feldman,& Berger, 2013). In a study of 34 perpetratorsof AHT, males were younger than females (27and 34, respectively), and victims of males had
more severe acute presentations, neurosurgical interventions, and worse clinical outcomes(Esernio-Jenssen, Tai, & Kodsi, 2011).
Other evaluations of the effects of providing information to new mothers have reported
decreases in the incidence of AHT. A programin western New York State provided a parental education program delivered by nurses
about violent infant shaking. The result was a
47% decrease (from 41.5 cases per 100,000 to
22.2/100,000) in the incidence of AHT during a 5.5-year study period, 1998-2004 (Diaset al., 2005). Another parent educational SBS
prevention program also delivered by nurses
was conducted in New York State, 2005-2008,
found a 75% reduction in infants treated forshaking injuries, from 14 cases in five years to
2 cases in three years (Altman et al., 2011).
Most AHT prevention programs aimed
at increasing new mothers’ knowledge about
infant crying and the risks of shaking occur in
hospital. In a German population-based studyof AHT knowledge, a large majority stated thatthey thought AHT education should occur
before birth (Berthold et al., 2019). Educationof new parents prior to birth might be easierfor them to incorporate into learning to be parents when they are not distracted or otherwise
occupied learning to care for an infant. It also
gives a better opportunity for additional sessions after a child’s birth. There are additional

8 • Joining Forces/Joining Families

procedures that are simple and easy to implement following the initial briefing of the newmother (and father, hopefully). Among these
are text message reminders, home visits, andfollow-up phone calls.
In addition to educating parents andcaregivers about infant crying and the risksof shaking, another factor to consider to help
those who are frustrated with the challenges
of consoling a crying infant is the potential
for disturbance of the parent-infant relationship. Parents who are unable to console theirinfants may feel rejected, that they are not goodparents, and cannot cope with parenthood. A
review of the impact of crying on this relationship emphasized the importance of programs,
such as home visiting and social and medical
services, to help parents with challenges of
infant crying during this early period. Failureof parents to meet these challenges can result in
diminishing the parents’ enjoyment of the early
weeks and months of their child’s life that may
be remembered with a sense of loss and regret
and decrease parent-infant bonding, which
has implications for future child development(Oldbury & Adams, 2015).

References

Altman RL, Canter J, Patrick PA, Daley N, ButtNK, & Brand DA. (2011). Parent education bymaternity nurses and prevention of abusive
head trauma. Pediatrics; 128(5): e1164-e1172.
Barr RG. (2012). Preventing abusive head trauma
resulting from a failure of normal interaction
between infants and their caregivers. Proceedings of the National Academy of Sciences;
109(Supplement_2): 17294-17301.
Barr RG, Rajabali F, Aragon M, Colbourne M, &Brant R. (2015). Education about crying inb
normal infants is associated with a reductionin pediatric emergency room visits for crying
complaints. Journal of Developmental and
Behavioreal Pediatrics; 36: 252-257.
Barr RG, Rivara FP, Barr M, Cummings P, Taylor
J, Lengua LJ, & Meredith-Benitz E. (2009).
Effectiveness of educational materials designed
to change knowledge and behaviors regarding
crying and shaken-baby syndrome in mothersof newborns: a randomized, controlled trial.
Pediatrics; 123(3): 972-980.
Barr RG, Trent RB, & Cross J. (2006). Age-related
incidence curve of hospitalized Shaken Baby
Syndrome cases: convergent evidence forcrying as a trigger to shaking. Child Abuse &Neglect; 30(1): 7-16.
Continued on p. 11
Fall 2019

BUILDING BRIDGES TO RESEARCH

Sensitivity and Specificity: Two Statistical Measures
Used in Tests Screening for Disease
By James E. McCarroll, PhD, Joshua C. Morganstein, MD, Ronald J. Whalen, PhD
and Robert J. Ursano, MD

Screening is aprocedure in medical
practice to identify
people with a diseaseor condition so thatthey may be brought
to treatment.

Screening. Screening is a procedure in
medical practice to identify people with a disease or condition so that they may be brought
to treatment. Screening aims to separate people
into those who have the condition and those
who do not. Ideally, a screening test would give
perfect results in achieving this separation, but
tests are rarely this precise. Screening results
are typically a probability statement, usually
expressed as a percent.
Sensitivity and Specificity. The ability of atest to correctly identify people with the condition is known as its sensitivity. A perfect test
should also identify people who do not havethe condition. This is known as the specificityof the test. Calculating sensitivity and specificity requires knowledge of (1) those persons
who are correctly identified as having or nothaving the condition (true positives and true
negatives) and (2) those persons who are incorrectly identified as having and not having thecondition (false positives and false negatives).
The table below shows the relationships ofthese measures.

Sensitivity. For an imaginary screening
test, if the sensitivity were 95%, the test would
correctly identify 95% of patients with thecondition, but would miss 5% who have thecondition. A highly sensitive test casts a broad
net in order to minimize missed cases (false
negatives). Good screening tests have highsensitivity.
Specificity. Again, for an imaginary screening test, if specificity were 95%, the test would
correctly identify those without the condition,
but would fail to identify 5% who had thecondition. A highly specific test casts a net with
precise aim, to minimize those who do not havethe condition, but are incorrectly identified as
positive (false positives). Good screening tests
have high specificity.
Screening tests are not diagnostic. Oncea person has been identified as having a highprobability of having the condition, then doctors will apply a good diagnostic test to confirm
the symptoms of the condition.

Relationships between Condition and Test Results			Persons with the Condition

Persons Without the Condition

Positive
Test Result			True Positives
Persons with condition
and test positive

False Positives
Persons without condition
but test positive

Negative
Test Result			

False Negatives
Persons with condition,
but test negative

True Negatives
Persons without condition
and test negative

Sensitivity equals

True Positives
True Positives + False Negatives

Specificity equals

True Negatives
True Negatives + False Positives

http://www.CSTSonline.org

Joining Forces/Joining Families • 9

An interview with Kent P.
Hymel, MD, from page 4

In summary, what weare trying to do is use
evidence to informtwo key decisions that
doctors have to makein these cases — “DoI work them up?”and then later, “Do I
diagnose and report?”

multicenter study to measure the predictive
properties of the variables and find out what
combination works best to accomplish yourgoal, which in this case is to develop a screen.
You call that a derivation study; you are deriving the rule (Hymel et al., 2013). Second, youthen have to complete a second multicenter
study and demonstrate that in an equivalentpatient population, that it performs just as well
as you said it would in the first study. You arevalidating its performance and so we call that avalidation study. We completed the validation
study (Hymel et al., 2014). The third expected
step in the development of a clinical prediction rule is called the implementation or impact
study, which is currently underway. We are
now for the first time trying to get doctors toapply the screen in PICU settings. We havefour PICU sites where we are deploying thesestrategies and working to get doctors to use thescreening tool and follow its recommendations.
We also have four matched sites where thedoctors are practicing screening and making
decisions to workup or not workup children
in their usual way without the screen rules.
We are hoping that doctors at our intervention
sites will apply the criteria significantly more
frequently than the doctors at the control sites.
If they do that, we may be able to demonstratethat the tool has a positive impact on patients.
If that is accomplished, we expect to see a lower
frequency of what we call missed cases.
Let’s move on to the next step: the clinicalprediction rule research. Whereas the purposeof the four-variable rule was to inform anddirect doctors to work up a head-injured childfor abuse, the second rule was developed toallow doctors to predict the probability that thechild’s injuries were due to abuse. This second
rule has seven variables. The seven included
the same four variables that we used to makethe rule to inform doctors to perform theevaluation for AHT. We then added three additional variables. These are (1) a retinal exam
(by an ophthalmologist) of the photoreceptor
layers in the back of the eye to look for retinal
hemorrhages; (2) a skeletal survey to look for
associated fractures; and (3) any brain hypoxia,
ischemia, or swelling hypoxia/ischemia of thebrain. This third variable the supply of oxygento the brain was inhibited or cut off by theabuse.
The seven variables did the trick. The realsurprise for me was that the four variables thatwere included in the original screening tool
ended up included in the seven-variable rule.

10 • Joining Forces/Joining Families

This adds a significant level of simplicity to thewhole process. So now, if you think of the timeline of a child’s hospitalization, doctors can apply the screening rule at the time of admission
using just four variables to decide if they should
do a workup. They then wait a while and getback the results of the tests performed as part ofthe evaluation and then they apply the sevenvariable rule to inform their decision, “Ok, now
do I diagnose or report based on these results?”
In summary, what we are trying to do is use
evidence to inform two key decisions that doctors have to make in these cases — “Do I work
them up?” and then later, “Do I diagnose andreport?” You could describe the screening tool
as a more directive decision rule. It’s directing
behavior. It is saying, work him up if you haveone or more. The seven-variable rule is a prediction tool. It is giving you an estimate of theprobability in order to inform rather than direct
their decision to diagnose or report.
Dr. McCarroll: That is very interesting.
Dr. Hymel: The beauty of it is that it can all
be made simple because it is manageable witha hand-held phone app. At the intervention
sites the doctors have access to the prediction
tools. If they ask the question, “Which of thosevariables are present?” it gives them a number,an estimate of probability.
Dr. Whalen: You talked about the ongoing
impact study. Will you be able to go back andlook at the clinical decision-making on the
missed cases?
Dr. Hymel: Yes. These results are preliminary, but it turns out that there are site-specific,
physician-specific, and patient-specific variables that appear to be impacting decisions by
doctors whether to apply the screening tool andfollow its recommendations or not. The preliminary look at the data suggests that smallersites are adopting it more readily than larger
sites. Perhaps that is because at the large sites
there are more physicians and therefore each ofthem has fewer opportunities to consider applying it to a patient. The larger sites are a bigger
challenge, a more diverse physician population.
What I am learning now is that change comesslowly. But, we are only in the beginning of thethird year of a five-year study.
Dr. McCarroll: Thank you for the interview andfor your research. We will certainly inform ouraudience of some of the many complexities of
AHT and AHT research.
Continued on p. 11
Fall 2019

An interview with Kent P.
Hymel, MD, from page 10

Dr. Hymel: Thank you for your interest in
this research.

References

Hymel KP, Armijo-Garcia V, Foster R, Frazier
TN, Stoiko M, Christie LM.,… (PediBIRN).
(2014). Validation of a clinical prediction rule
for pediatric abusive head trauma. Pediatrics;
134(6): e1537-e1544.
Hymel KP, Laskey AL, Crowell KR, Wang M,
Armijo-Garcia V, Frazier TN, . . . (PediBIRN).
(2018). Racial and ethnic disparities and bias
in the evaluation and reporting of abusive
head trauma. Journal of Pediatrics; 198: 137143.
Hymel KP, Willson DF, Boos SC, Pullin DA,
Homa K, Lorenz DJ, … (PediBIRN). (2013).
Derivation of a clinical prediction rule for pe-

Prevention of Abusive Head
Trauma in Infants,from page 8

Berthold O, Witt A, Clemens V, Brahler E, Plener
PL, & Fegert JM. (2019). Do we get the message through? Difficulties in the preventionof abusive head trauma. European Journal of
Pediatrics; 178(2): 139-146.
Esernio-Jenssen D, Tai J, & Kodsi S. (2011). Abusive head trauma in children: a comparisonof male and female perpetrators. Pediatrics;
127(4): 649-657.
Fanconi M, & Lips U. (2010). Shaken baby syndrome in Switzerland: results of a prospective
follow-up study. European Journal of Paediatrics; 169(8): 1023-1028.
King WJ, MacKay M, & Sirnick A. (2003). Shaken
baby syndrome in Canada: clinical characteristics and outcome of hospital cases. Canadian
Medical Association Journal; 168(2): 155-159.

diatric abusive head trauma. Pediatric Critical
Care Medicine; 14(2): 210-220.
Jenny C, Hymel KP, Ritzen A, Reinert SE, & Hay
TC. (1999). Analysis of missed cases of abusive
head trauma. JAMA: The Journal of the American Medical Association; 281(7): 621-626.
Klevens J, & Leeb RT. (2010). Child maltreatment
fatalities in children under 5: Findings fromthe National Violence Death Reporting System. Child Abuse & Neglect; 34(4): 262-266.
Leventhal JM, & Edwards GA. (2017). Flawed
theories to explain child physical abuse: What
are the medical-legal consequences? The
Journal of the American Medical Association;318(14): 1317-1318.

Lopes NRL, & Williams LCdA. (2018). Pediatricabusive head trauma prevention initiatives: A
literature review. Trauma, Violence, & Abuse;
19(5): 555-566.
Oldbury S, & Adams K. (2015). The impact ofinfant crying on the parent-infant relationship.
Community Practitioner; 88(3): 29-34.
Reese LS, Heiden EO, Kim KQ, & Yang J. (2014).
Evaluation of Period of PURPLE Crying, anabusive head trauma prevention program.
Journal of Obstetric, Gynecologic & Neonatal
Nursing; 43(6): 752-761.
Scribano PV, Makoroff KL, Feldman KW, &Berger P. (2013). Association of perpetrator
relationship to abusive head trauma clinical outcomes. Child Abuse & Neglect; 37(10):771-777.

Klevens J, & Leeb RT. (2010). Child maltreatment
fatalities in children under 5: Findings fromthe National Violence Death Reporting System. Child Abuse and Neglect; 34(4): 262-266.

http://www.CSTSonline.org

Joining Forces/Joining Families • 11

Websites of Interest
A Center for Disease Control and Prevention (CDC) website describes
abusive head trauma (AHT). It includes definitions of AHT as well as ICD-9
and ICD-10 codes diagnosing non-fatal and fatal AHT. This document canbe helpful for emergency room physicians as well as researchers.
https://www.cdc.gov/violenceprevention/pdf/pedheadtrauma-a.pdf
This American Academy of Pediatrics (AAP) website gives backgroundinformation on AHT for reporters. It includes facts about AHT andemphasizes prevention, the validity of the diagnosis, and supporting
medical references about these issues.
https://www.aap.org/en-us/about-the-aap/aap-press-room/aap-pressroom-media-center/Pages/Abusive-Head-Trauma-Fact-Sheet.aspx
Another and more extensive AAP document entitled “Understanding
Abusive Head Trauma in Infants and Children” gives extensive
descriptions of what is AHT, how it is identified, and a discussion andrefutation of the argument that the diagnoses of AHT and Shaken Baby
Syndrome (SBS) are not valid. It is important that readers understand that
AHT/SBS is a valid and well supported medical diagnosis.
https://www.aap.org/en-us/Documents/cocan_understanding_aht_in_
infants_children.pdf
The National Center on SBS website gives extensive data on SBS
including statistics on its incidence, costs, and outcomes. It includes
statements of consensus from major international health organizations
on the diagnosis and impact of SBS/AHT on children. It also contains an
extensive reference list on SBS and AHT.
https://www.dontshake.org/learn-more/itemlist/category/13-facts-info
Period of Purple Crying website contains information about the programthat helps parents understand that crying by an infant is usually a normalpart of their development. In addition to other resources, it includes
a video featuring Dr. Ronald Barr who describes program and theimportance of preventing AHT/SBS.
http://www.purplecrying.info/what-is-the-period-of-purple-crying.php
The Pediatric Brain Injury Research Network (PediBIRN) is a research
consortium that has included 18 hospitals in which pediatricians
have contributed to the research. Dr. Hymel is the founder, principal
investigator, and director of this project. The PediBIRN website describes
the ongoing study to implement the clinical decision tool (CDR) for
estimates of the probability of abusive head trauma. The website
contains a video by Dr. Hymel in which he explains the PediBIRN project.
For pediatricians who join the research, the website has data forms
that physicians can use to input data to the study as well as the AHT
probability calculator that physicians are urged to use in evaluating headinjured children for the probability of abuse.
http://www.pedibirn.com/
A CDC website Preventing Abusive Head Trauma in Children gives facts
about AHT as well as addition resources including a 52-page manual for
preventing child abuse and neglect.
http://www.cdc.gov/violenceprevention/childabuseandneglect/AbusiveHead-Trauma.html

12 • Joining Forces/Joining Families

Fall 2019