SHAKEN BABY IMPACT SYNDROME
Through this landmark study, Dr. Ommaya determined two
things. First, he determined that when the primate’s head was subjected
to sufficient angular or rotational acceleration (e.g., whiplash) force,
traumatic brain injury would occur regardless of whether or not skull
Second, he determined that traumatic brain injury,
subdural hematomas, or diffuse axonal injury did not occur until the
primate experienced approximately 155 gs
of acceleration force.
other words, Dr. Ommaya “demonstrated the concept of an injury
threshold for neural tissue.”
In postulating his whiplash shaking
theory, however, some experts argue that Dr. Caffey relied solely on Dr.
Ommaya’s finding that cranial injuries occurred without impact, while
specifically ignoring the amount or degree of force Dr. Ommaya (i.e.,
155 “g” forces) determined necessary to actually cause traumatic brain
Ommaya, supra note 22, at 285-86.
“The term g force or gee force refers to the symbol
, the force of acceleration due to
gravity at the earth's surface” Wikipedia, The Free Encyclopedia, Acceleration Due to
Gravity, http://www.factbook.org/ wikipedia/en/g/ge/gee.html (last visited Sept. 11,
2006) (“The acceleration due to gravity denoted g (also gee) is a non-SI unit of
acceleration defined as exactly 9.80665 m/s
or 9.80665 m/s^2 (almost exactly 32.174
.”). Id. (Gravity due to the earth is experienced the same as being accelerated
upward with an acceleration of 1 g. The total g-force is found by vector addition of the
opposite of the actual acceleration (in the sense of rate of change of velocity) and a vector
of 1 g downward for the ordinary gravity (or in space, the gravity there.)). Id.
Werner Goldsmith & John Plunkett, A Biomechanical Analysis of the Causes of
Traumatic Brain Injury in Infants and Children, 25 A
(June 2004) (stating that Dr. Ommaya measured force in units of angular
acceleration using the formula radians per second-per second. Goldsmith and Plunkett
convert this measurement to “g” forces which, arguably, is more recognizable by both
legal practitioners and juries.).
Uscinski, supra note 22, at 76-7.
Faris Bandak, Shaken Baby Syndrome: A Biomechanics Analysis of Injury
Mechanisms, 151 F
71, 76 (2005) (“Caffey translated Ommaya’s
results without considering injury biomechanics, into an explanation for a confession of
shaking.”); Sharp, supra note 18, at 35.
Caffey concluded that just as acceleration-deceleration without an
impact (i.e., free shaking or ‘whiplash’) damaged the monkeys’
brains, this also explained how parents inflicted brain injuries on their
babies. [Caffey] actually telephoned Ommaya to thank him for the
article. Today, Ommaya is adamant that he told Caffey that
acceleration-deceleration forces involved in the monkey experiment
were much greater than he believed could be generated by a human.
MILITARY LAW REVIEW
For roughly the next fifteen years, Dr. Caffey’s shaking-alone theory
circulated through both the medical and legal communities and went
virtually unchecked without the benefit of any significant peer review.
As a result, Dr. Caffey’s theory became firmly ingrained as an accepted
2. The Minority View—Shaking Plus Impact
It was not until approximately 1987 that the first skeptics began
questioning the accuracy of Dr. Caffey’s study and his theory.
the first to question Dr. Caffey’s theory was Dr. Ann-Christine Duhaime
who observed that “[w]hile the term ‘shaken baby syndrome’ has
become well entrenched in the literature of child abuse, it is
characteristic of the syndrome that a history of shaking in such cases is
As a result of her observation, Dr. Duhaime conducted a
biomechanical study to determine whether an adult could, by means of
shaking alone, exert sufficient force to produce traumatic brain injury in
Sharp, supra note 18, at 35.
Uscinski, supra note 22, at 76 (“Two further papers by Caffey over the next two years
emphasized shaking as a means of inflicting intracranial bleeding in children. After
publication of these papers, shaken baby syndrome became widely accepted as a clinical
diagnosis for inflicted head injury in infants.”); Letter from John Plunkett, M.D., forensic
pathologist, Regina Medical Facility, to American Journal of Forensic Medicine and
Pathology, Shaken Baby Syndrome and Other Mysteries (Spring 1998) (on file with
author) [hereinafter Plunkett Letter].
I suspect that Caffey and others evaluating head injuries in the ‘40s,
‘50s and ‘60s asked a number of caretakers if the infant had been
‘shaken’ and were told ‘yes’ in at least some cases. The caretakers
were never asked about an ‘impact’ because direct trauma was not
part of the theory. Scientific theory was quickly accepted as
scientific fact: Subdural hemorrhage and retinal hemorrhage in an
unconscious or dead child is a shaken infant; there is no need to
‘prove otherwise,’ only a fall from a two story building or a motor
vehicle accident could cause such an injury, if it was not due to
shaking. Studies critically evaluating the biomechanics of rotational
brain injury and a subdural hematoma, available from experiments
performed for (among others) the automotive industry and the space
program, were forgotten, not sought or ignored.
Duhaime et al., supra note 3, at 409, 414.
Id. at 409.
SHAKEN BABY IMPACT SYNDROME
Using infant models, Dr. Duhaime and her team subjected
proportionately correct models to a series of shaking events, some of
which were followed by an impact.
Using Dr. Ommaya’s 155 gs as the
threshold for when traumatic brain injuries (e.g., subdural hematoma,
retinal hemorrhages, diffuse axonal injury) manifest themselves, Dr.
Duhaime observed that shaking alone produced at most only 9.3 gs
force, a mere fraction of the force Dr. Ommaya determined was required
to cause subdural hematomas, retinal hemorrhages, or diffuse axonal
injury. However, when the “shakers” were asked to create an impact by
“slamming” the models’ heads into a fixed object, Dr. Duhaime observed
that the force produced was equivalent to almost 428 gs, an increase
fifty-times greater than that of shaking alone.
As a direct result, Dr.
Duhaime and her team concluded that “severe head injuries commonly
diagnosed as shaking injuries require impact to occur and that shaking
alone in an otherwise normal baby is unlikely to cause the shaken baby
As a result of this questioning, the minority view―the
Id. at 409-11.
Id. at 413.
Id. at 413.
Id. at 409.
It is our conclusion that the shaken baby syndrome, at least in its
most severe acute form, is not usually caused by shaking alone.
Although shaking may in fact be part of the process, it is more likely
that such infants suffer blunt impact. The most common scenario
may be a child who is shaken, then thrown into or against a crib or
other surface, striking the back of the head and thus undergoing a
large, brief deceleration. This child has both types of injuries-impact
with its resulting focal damage, and severe acceleration-deceleration
effects associated with impact causing shearing effects on the vessels
Id. at 414.
Ann-Christine Duhaime, et al., Nonaccidental Head Injury in Infants-The “Shaken
Baby Syndrome,” 338 N
1822 (1998) (“Thus, the term ‘shaking-impact
syndrome’ may reflect more accurately than ‘shaken-baby syndrome’ the usual
mechanism responsible for these injuries.”).
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B. The Emerging View—Shaking Without a Corresponding Neck Injury
Proves Shaking Plus Impact
In recent years, numerous published medical studies have strongly
supported the minority position.
In 2002, Dr. Ommaya published an
article postulating that if it were possible for an infant to suffer traumatic
brain injury by shaking alone, the infant would also suffer a significant
corresponding neck injury.
He further concluded that the “[a]bsence of
cervical spinal cord injury would indicate a component of impact in the
presence of hemorrhagic brain lesions.”
In February 2005, Dr. Bandak,
using Dr. Ommaya’s injury threshold criteria, postulated that if an infant
was shaken hard enough to cause traumatic brain injury, the infant would
almost certainly have some form of significant neck injury.
Or to put it
plainly, absent a corresponding neck injury, the child was not shaken to
the point of traumatic brain injury.
C. Why Practitioners Should Know the Divergent Views
Practitioners should be aware of the minority and emerging views for
two primary reasons. First, an understanding of the medical literature in
this area will assist practitioners in effectively questioning witnesses.
Second, understanding the minority or emerging views may assist
defense counsel in making a motion to request expert assistance, to
disqualify a proffered government witness from being considered an
expert, or to challenge the scientific basis upon which an alleged expert
See Leestma, supra note 14; Bandak, supra note 28; Ayub Ommaya, Werner
Goldsmith, & L. Thibault, Biomechanics and Neuropathology of Adult and Pediatric
Head Injury, 16 B
Ommaya et al., supra note 39, at 220-21.
Id. at 228-29 (“At these levels of inertial loading, induced impulsively without contact,
the neck torque in the infant would cause severe injury to the high cervical cord and spine
long before the onset of cerebral concussion.”).
Bandak, supra note 28, at 71 (“We have determined that an infant head subjected to
the levels of rotational velocity and acceleration called for in the SBS literature, would
experience forces on the infant neck far exceeding the limits for structural failure of the
, R.C.M. 703(d) (2005)
[hereinafter MCM]; M
(2002); see also Daubert v. Merrell Dow Pharms., 509 U.S. 579 (1993); United States v.
Warner, 62 M.J. 114 (2005); United States v. Houser, 36 M.J. 392 (C.M.A. 1993). These
resources are the starting point for seeking expert assistance or expert witness testimony.
SHAKEN BABY IMPACT SYNDROME
V. Types of Injuries Caused by SBS/SIS
Experts differ regarding the degree and type of force (i.e., shaking
alone or shaking plus impact) necessary to trigger traumatic brain
Regardless of their biases concerning injury thresholds,
however, most experts agree on the types of injuries shaking or impact
can inflict. These injuries are generally broken down into the following
two categories: primary injuries and secondary injuries.
Primary cranial injuries consist of subdural hematomas, epidural
hematomas, subarachnoid hemorrhage, retinal hemorrhages, and diffuse
In cases involving cranial impact, the following injuries
may also be present: external scalp bruising under the point of impact,
extravasted blood under the point of impact (i.e., blood within the
epidural layer (scalp)), skull fracture(s), coup contusions (i.e., bruising or
injury beneath the site of impact), and contra-coup contusions (i.e.,
bruising or injury directly opposite the impact).
consist of brain hypoxia (i.e., insufficient oxygen flow to the brain),
brain ischemia (i.e., insufficient blood flow to the brain), and cerebral
edema (i.e., swelling of the brain).
With the exception of diffuse
axonal injury, the primary injuries listed above usually do not cause
A significant primary injury, however, may trigger a secondary
injury (e.g., such as cerebral edema), which can cause death.
“Primary injury occurs at the time of impact, either by a direct injury
to the brain parenchyma or by an injury to the long white matter tracts
through acceleration-deceleration forces . . . . The secondary injury is
represented by systemic and intracranial events that occur in response to
the primary injury and further contribute to neuronal damage and cell
Put another way, a primary injury is the injury that is caused by
or directly results from the act inflicting the trauma, whereas a secondary
injury is the injury that results from or is the byproduct of the primary
See Leestma, supra note 14; Plunkett, supra note 15; Uscinski, supra note 22;
Goldsmith & Plunkett, supra note 26; Bandak, supra note 28.
Lieutenant Colonel Kent Hymel, Abusive Head Trauma? A Biomechanics-Based
Approach, 3 C
116-17 (May 1998).
Id. at 117, 119; see also infra app. A.
Bandak, supra note 28, at 79; see also infra app. A.
Wilkins, supra note 1, at 394.
Hymel, supra note 46, at 118.
Arabela Stock, Emedicine-Access to the Minds of Medicine, Head Trauma (Sept. 15,
MILITARY LAW REVIEW
injury. Consider the following example: Joe is punched in the face and
his jaw is broken. As a result, Joe’s mouth swells up and blocks his
airway. The broken jaw is the primary injury which, in turn, caused the
secondary injury of the blocked airway.
VI. Why the Lesson in Primary and Secondary Injuries?
The legal practitioner must be able to recognize and distinguish
primary versus secondary injuries for two important reasons. First,
primary injuries can be linked to their biomechanical origins (i.e., their
whereas secondary injuries generally cannot.
certain injuries are indicative of specific acts, such as an epidural
hemorrhage being specifically indicative of an impact.
injury, however, may have many different causes and is not indicative of
any specific, telltale act, origin, or cause.
For example, cerebral edema
is a secondary injury. Cerebral edema can occur with blunt force trauma,
with whiplash, because a large subdural hematoma displaces the brain
cutting off oxygen and causing it to swell, or from extended attachment
to or reliance upon a respirator.
None of these examples, however,
indicate the specific act or incident that caused the primary injury which,
in turn, triggered the cerebral edema (the secondary injury).
Second, in addition to identifying the cause of the injury, primary
injuries can, to a certain degree, often be used to date or time stamp when
an injury occurred.
A subdural hematoma (SDH) is classified by the amount
of time that has elapsed from the inciting event, if
Ayub Ommaya, Head Injury Mechanisms and the Concept of Preventive Management,
, 527-28 (1995); Bandak, supra note 28, at 72.
Bandak, supra note 28, at 72 (“Primary injuries are those caused directly by the
mechanical insult and secondary injuries result as part of the pathophysio
logical progression following primary injury.”).
Telephone Interview with John M. Plunkett, Forensic Pathologist and Coroner, Regina
Medical Facility (Dec. 4, 2005) [hereinafter Plunkett Telephone Interview].
Bandak, supra note 28, at 72, 78-9.
SBSDefense.com, “Shaken Baby Syndrome”- A Tutorial and Review of the
Literature, http://www.sbsdefense.com/SBS_101.htm (last visited Sept. 12, 2006)
[hereinafter SBSDefense.com] (noting that some experts claim prolonged use of a
respirator can mask or mimic the finding of diffuse axonal injury).
Grant Sinson & Tim Reiter, Emedicine, Subdural Hematomas, Jan. 12, 2002,
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