Shaken baby syndrome

New Insights into the Diagnosis and Age Determination of Retinal Hemorrhages from Abusive Head Trauma: A Systematic Review

(1) Background: Head trauma represents the first cause of death in abused children, but diagnostic knowledge is still limited. The characteristic findings of abusive head trauma (AHT) are retinal hemorrhages (RH) and additional ocular findings, including optic nerve hemorrhages (ONH). However, etiological diagnosis must be cautious. (2) Methods: The Preferred Reporting Items for Systematic Review (PRISMA) standards were employed, and the research focus was the current gold standard in the diagnosis and timing of abusive RH. (3) Results: Sixteen articles were included for qualitative synthesis. The importance of an early instrumental ophthalmological assessment emerged in subjects with a high suspicion of AHT, with attention to the localization, laterality, and morphology of the findings. Sometimes it is possible to observe the fundus even in deceased subjects, but the current techniques of choice consist of Magnetic Resonance Imaging and Computed Tomography, also useful for the timing of the lesion, the autopsy, and the histological investigation, especially if performed with the use of immunohistochemical reactants against erythrocytes, leukocytes, and ischemic nerve cells. (4) Conclusions: The present review has made it possible to build an operational framework for the diagnosis and timing of cases of abusive retinal damage, but further research in the field is needed.

Imaging of Abusive Head Trauma in Children

In this article, we describe relevant anatomy, mechanisms of injury, and imaging findings of abusive head trauma (AHT). We also briefly address certain mimics of AHT, controversies, pearls, and pitfalls. Concepts of injury, its evolution, and complex nature of certain cases are highlighted with the help of case vignettes.

Providing a Forensic Expert Opinion on the "Degree of Force": Evidentiary Considerations

Forensic pathologists and anthropologists are often asked in court for an opinion about the degree of force required to cause a specific injury. This paper examines and discusses the concept of 'degree of force' and why it is considered a pertinent issue in legal proceedings. This discussion identifies the implicit assumptions that often underpin questions about the 'degree of force'. The current knowledge base for opinions on the degree of force is then provided by means of a literature review. A critical appraisal of this literature shows that much of the results from experimental research is of limited value in routine casework. An alternative approach to addressing the issue is provided through a discussion of the application of Bayes' theorem, also called the likelihood ratio framework. It is argued that the use of this framework makes it possible for an expert to provide relevant and specific evidence, whilst maintaining the boundaries of their field of expertise.

Pediatric abusive head trauma

Abusive head trauma (AHT), used to be named shaken baby syndrome, is an injury to the skull and intracranial components of a baby or child younger than 5 years due to violent shaking and/or abrupt impact. It is a worldwide leading cause of fatal head injuries in children under 2 years. The mechanism of AHT includes shaking as well as impact, crushing or their various combinations through acceleration, deceleration and rotational force. The diagnosis of AHT should be based on the existence of multiple components including subdural hematoma, intracranial pathology, retinal hemorrhages as well as rib and other fractures consistent with the mechanism of trauma. The differential diagnosis must exclude those medical or surgical diseases that can mimic AHT such as traumatic brain injury, cerebral sinovenous thrombosis, and hypoxic-ischemic injury. As for the treatment, most of the care of AHT is supportive. Vital signs should be maintained. Intracranial pressure, if necessary, should be monitored and controlled to ensure adequate cerebral perfusion pressure. There are potential morbidity and mortality associated with AHT, ranging from mild learning disabilities to severe handicaps and death. The prognosis of patients with AHT correlates with the extent of injury identified on CT and MRI imaging. The outcome is associated with the clinical staging, the extent of increased intracranial pressure and the existence of neurological complications such as acquired hydrocephalus or microcephalus, cortical blindness, convulsive disorder, and developmental delay. AHT is a potentially preventable disease, therefore, prevention should be stressed in all encounters within the family, the society and all the healthcare providers.

Shock wave propagation along the central retinal blood vessels

Retinal haemorrhage is often observed following brain injury. The retinal circulation is supplied (drained) by the central retinal artery (vein) which enters (leaves) the eye through the optic nerve at the optic disc; these vessels penetrate the nerve immediately after passing through a region of cerebrospinal fluid (CSF). We consider a theoretical model for the blood flow in the central retinal vessels, treating each as multi-region collapsible tubes, where we examine how a sudden change in CSF pressure (mimicking an injury) drives a large amplitude pressure perturbation towards the eye. In some cases, this wave can steepen to form a shock. We show that the region immediately proximal to the eye (within the optic nerve where the vessels are strongly confined by the nerve fibres) can significantly reduce the amplitude of the pressure wave transmitted into the eye. When the length of this region is consistent with clinical measurements, the CSF pressure perturbation generates a wave of significantly lower amplitude than the input, protecting the eye from damage. We construct an analytical framework to explain this observation, showing that repeated rapid propagation and reflection of waves along the confined section of the vessel distributes the perturbation over a longer lengthscale.

Traumatic shaking: The role of the triad in medical investigations of suspected traumatic shaking

The Swedish Agency for Health Technology Assessment and Assesment of Social Services (SBU) is an independent national authority, tasked by the government with assessing methods used in health, medical and dental services and social service interventions from a broad perspective, covering medical, economic, ethical and social aspects. The language in SBU's reports are adjusted to a wide audience. SBU's Board of Directors has approved the conclusions in this report. The systematic review showed the following graded results: There is limited scientific evidence that the triad (Three components of a whole. The triad associated with SBS usually comprises subdural haematoma, retinal haemorrhages and encephalopathy.) and therefore, its components can be associated with traumatic shaking (low-quality evidence). There is insufficient scientific evidence on which to assess the diagnostic accuracy of the triad in identifying traumatic shaking (very low-quality evidence). Limited scientific evidence (low-quality evidence) represents a combined assessment of studies of high or moderate quality which disclose factors that markedly weaken the evidence. It is important to note that limited scientific evidence for the reliability of a method or an effect does not imply complete lack of scientific support. Insufficient scientific evidence (very low-quality evidence) represents either a lack of studies or situations when available studies are of low quality or show contradictory results. Evaluation of the evidence was not based on formal grading of the evidence according to GRADE but on an evaluation of the total scientific basis.

National study shows that abusive head trauma mortality in Sweden was at least 10 times lower than in other Western countries

AIM

The validity of the diagnostic criteria for abusive head trauma (AHT) and its attributes has been widely debated. This national study investigated the possibility of false-positive and false-negative cases of fatal AHT in Sweden.

METHOD

This was a retrospective evaluation of the records of 733 deceased infants up to the age of 365 days who were examined during 1994-2013 at the six forensic medicine departments. All the records were scrutinised for possible cases of AHT.

RESULTS

We included 12 cases, of which eight had been diagnosed as AHT. Of these 12 infants, eight had a concomitant disease or perinatal illness, five were born prematurely and three were twins. Figures from other Western countries would suggest 6-7 deaths per 100,000 per year in Sweden, but in reality, there was a maximum possible incidence of 0.6 per 100,000 infants per year.

CONCLUSION

The risk of unreported fatal AHT in Sweden was low, and there may have been cases misdiagnosed as AHT. The at least 10 times lower incidence than has been reported from other Western countries, raises the question if previously reported higher incidences of fatal AHT have been exaggerated.

Shaken baby syndrome and the risk of losing scientific scrutiny

A systematic review of shaken baby syndrome by the Swedish Agency for Health Technology Assessment and Assessment of Social Services generated numerous reactions from professional organisations, even before the review was published. There was also a lively debate after a paper summarising its findings were published in Acta Paediatrica The various responses are worth debating further, as they raise several important issues with regard to research ethics, having an open debate and publishing scientific findings.

CONCLUSION

The responses to the shaken baby syndrome report indicate that scientific scrutiny risks being lost when researchers and organisations are not open to challenging established ideas.

Mechanical characterization of human brain tissue

Mechanics are increasingly recognized to play an important role in modulating brain form and function. Computational simulations are a powerful tool to predict the mechanical behavior of the human brain in health and disease. The success of these simulations depends critically on the underlying constitutive model and on the reliable identification of its material parameters. Thus, there is an urgent need to thoroughly characterize the mechanical behavior of brain tissue and to identify mathematical models that capture the tissue response under arbitrary loading conditions. However, most constitutive models have only been calibrated for a single loading mode. Here, we perform a sequence of multiple loading modes on the same human brain specimen - simple shear in two orthogonal directions, compression, and tension - and characterize the loading-mode specific regional and directional behavior. We complement these three individual tests by combined multiaxial compression/tension-shear tests and discuss effects of conditioning and hysteresis. To explore to which extent the macrostructural response is a result of the underlying microstructural architecture, we supplement our biomechanical tests with diffusion tensor imaging and histology. We show that the heterogeneous microstructure leads to a regional but not directional dependence of the mechanical properties. Our experiments confirm that human brain tissue is nonlinear and viscoelastic, with a pronounced compression-tension asymmetry. Using our measurements, we compare the performance of five common constitutive models, neo-Hookean, Mooney-Rivlin, Demiray, Gent, and Ogden, and show that only the isotropic modified one-term Ogden model is capable of representing the hyperelastic behavior under combined shear, compression, and tension loadings: with a shear modulus of 0.4-1.4kPa and a negative nonlinearity parameter it captures the compression-tension asymmetry and the increase in shear stress under superimposed compression but not tension. Our results demonstrate that material parameters identified for a single loading mode fail to predict the response under arbitrary loading conditions. Our systematic characterization of human brain tissue will lead to more accurate computational simulations, which will allow us to determine criteria for injury, to develop smart protection systems, and to predict brain development and disease progression.

STATEMENT OF SIGNIFICANCE

There is a pressing need to characterize the mechanical behavior of human brain tissue under multiple loading conditions, and to identify constitutive models that are able to capture the tissue response under these conditions. We perform a sequence of experimental tests on the same brain specimen to characterize the regional and directional behavior, and we supplement our tests with DTI and histology to explore to which extent the macrostructural response is a result of the underlying microstructure. Results demonstrate that human brain tissue is nonlinear and viscoelastic, with a pronounced compression-tension asymmetry, and we show that the multiaxial data can best be captured by a modified version of the one-term Ogden model.

Controversies in pediatric forensic pathology

Pediatric forensic pathology is an emerging medical subspecialty that spans the area between pediatric and forensic pathology. Advances in both of these fields have increased the sophistication of diagnoses, with overlap of disorders that might present to either the pediatric or forensic pathologist, adding further layers of complexity. Not surprisingly, therefore, there are important ethical and medical controversies in pediatric forensic pathology that merit careful consideration and attention.

Mechanics of the brain: perspectives, challenges, and opportunities

The human brain is the continuous subject of extensive investigation aimed at understanding its behavior and function. Despite a clear evidence that mechanical factors play an important role in regulating brain activity, current research efforts focus mainly on the biochemical or electrophysiological activity of the brain. Here, we show that classical mechanical concepts including deformations, stretch, strain, strain rate, pressure, and stress play a crucial role in modulating both brain form and brain function. This opinion piece synthesizes expertise in applied mathematics, solid and fluid mechanics, biomechanics, experimentation, material sciences, neuropathology, and neurosurgery to address today’s open questions at the forefront of neuromechanics. We critically review the current literature and discuss challenges related to neurodevelopment, cerebral edema, lissencephaly, polymicrogyria, hydrocephaly, craniectomy, spinal cord injury, tumor growth, traumatic brain injury, and shaken baby syndrome. The multi-disciplinary analysis of these various phenomena and pathologies presents new opportunities and suggests that mechanical modeling is a central tool to bridge the scales by synthesizing information from the molecular via the cellular and tissue all the way to the organ level.

Factors associated with hemispheric hypodensity after subdural hematoma following abusive head trauma in children

Abusive head trauma (AHT) is a unique form of pediatric TBI with increased mortality and neurologic sequelae. Hemispheric hypodensity (HH) in association with subdural blood after AHT has been described. Though risk factors for HH are not understood, we hypothesized that risk factors could be identified. We retrospectively enrolled children under 5 years with TBI secondary to AHT (child advocacy diagnosis) who had undergone initial and interval brain imaging. Records were interrogated for prearrival and in-hospital physiologic and radiographic findings. HH was determined by a blinded observer. Twenty-four children were enrolled and 13 developed HH. HH was not significantly associated with age, initial Glascow Coma Scale, or mortality. Pediatric Intensity Level of Therapy (PILOT) scores (p=0.01) and daily maximal intracranial pressure (ICPmax; p=0.037) were higher in HH. Hypoxia, hypotension, cardiopulmonary arrest, need for blood transfusion, and daily blood glucoses tended to be greater in HH. Whereas all children with HH had acute subdural hematoma (SBH), many children without HH also had subdural blood; the presence of skull fracture was more likely in the children who did not develop HH (p=0.04), but no other intracranial radiographic pattern of injury was associated with HH. Surgical intervention did not appear to protect against development of HH. A variety of insults associated with ischemia, including intracranial hypertension, ICP-directed therapies, hypoxia, hypotension, and cardiac arrest, occurred in the children who developed HH. Given the morbidity and mortality of this condition, larger studies to identify mechanisms leading to the development of HH and mitigating clinical approaches are warranted.

[Birth-related retinal hemorrhages in the newborn: incidence and relationship with maternal, obstetric and neonatal factors. Prospective study of 2,031 cases]

PURPOSE

To assess the prevalence, morphology and distribution of retinal hemorrhages in healthy newborns and their relationship to neonatal, maternal and obstetrical factors, and to determine their natural history.

PATIENTS AND METHODS

The present study prospectively included 2,031 consecutive healthy newborns. Indirect ophthalmoscopy was performed within 24 hours after birth in all newborns. Infants with retinal hemorrhages were reexamined weekly until the hemorrhage resolved. Annual ophthalmologic follow-up was also scheduled in these children. Neonatal, maternal and obstetric parameters were analyzed in all newborns and compared between newborns with retinal hemorrhages and those without retinal hemorrhages.

RESULTS

31.8 % of newborns exhibited retinal hemorrhages. 72.6 % of hemorrhages were bilateral. They tended to be localized around the optic discs and in the posterior pole, but their distribution was variable. Retinal hemorrhages were of variable shapes. The prevalence of retinal hemorrhages was higher in newborns delivered with vacuum-assisted extraction (38 %, P<0.001), intermediate during normal vaginal delivery (32.6 %, P<0.001) and lower with cesarean section (20.8 %). Comparative analysis between elective cesarean section and emergency cesarean showed a higher incidence of retinal hemorrhages in the emergency cesarean group (P=0.006). On multivariate analysis, vacuum-assisted delivery was the only factor associated with a higher prevalence of retinal hemorrhages in newborns (P=0.045). Two thirds of hemorrhages had disappeared by one week after birth. Retinal hemorrhages had resolved in all newborns within four weeks.

CONCLUSION

Birth-related retinal hemorrhages are common (1/3 of our newborns). Vacuum-assisted delivery is the main risk factor in this study. All hemorrhages resolved by one month of age. These findings may help in differential diagnosis with shaken baby syndrome.

Prevalence of retinal hemorrhages in critically ill children

BACKGROUND

Retinal hemorrhages (RHs) with encephalopathy and subdural bleeding are considered suggestive of abusive head trauma (AHT). Existing studies describing RH focus on AHT and have potential selection bias. We undertook a prospective observational study to define the prevalence, distribution, and extent of RH in critically ill children.

METHODS

From February 2008 to December 2009, emergency intensive care admissions ≥ 6 weeks of age underwent dilated retinal examination by either a pediatric ophthalmologist or RetCam (retinal photograph) imaging after written informed consent. Patients with suspected or proven AHT, penetrating eye trauma, and elective admissions were excluded.

RESULTS

The prevalence of RH was 15.1% (24/159; 95% confidence interval [CI]: 9.5%-21%); 16/24 (66%) mild, and 2/24 (8%) moderate. Severe multilayered RH were seen in only 6 patients (3.7%), 3 with myeloid leukemia and sepsis, 2 with severe accidental head injury, and 1 with severe coagulopathy secondary to late onset hemorrhagic disease of newborn. There was no detectable impact of age, gender, seizures, coagulopathy or cardiopulmonary resuscitation on prevalence of severe multilayered RH; however, sepsis (odds ratio: 3.2; 95% CI: 1.3-8.0, P = .018) and coagulopathy (odds ratio: 2.8; 95% CI: 1.2-7.0, P = .025) were significantly associated with any RH. Only admission diagnosis was independently associated with severe multilayered RH on logistic regression.

CONCLUSIONS

RHs were seen in critically ill children with a prevalence of 15.1% (24/159); however, most were mild. Severe multilayered RH resembling those described in AHT were rare (6/24) and were only seen in patients with fatal accidental trauma, severe coagulopathy, sepsis with myeloid leukemia, or a combination of these factors.

Nonaccidental head injury is the most common cause of subdural bleeding in infants <1 year of age

OBJECTIVE

Subdural bleeding (SDB) in infants is considered an essential symptom of nonaccidental head injury (NAHI). Recently, this view has been challenged by the "unified hypothesis," which claims that SDB in infants is related to hypoxia and brain swelling rather than to traumatic shearing of bridging veins. We analyzed a large series of infants' autopsies for the presence and causes of SDB, which should be a common event according to the unified hypothesis.

METHODS

Autopsy, clinical, and legal information for infants <1 year of age from a single institution over 50 years were analyzed regarding cause of death, presence, morphology, and cause of SDB, and brain weight.

RESULTS

From a total of 16 661 autopsies during the study period, 715 (4.3%) involved infants <1 year of age. Fifty (7.0%) of those had SDB. NAHI was identified in 17 patients. The most common cause of SDB was trauma (15 cases [30.0%]), with NAHI accounting for 14 cases. SDB was present in 82.4% of patients with NAHI but only 5.2% of infants with other causes of death. Four patients (8.0%) had unexplained SDB with no discernible cause of bleeding. Statistical analysis did not reveal any correlation between the presence of SDB and brain weight.

CONCLUSIONS

In the study population, unexplained SDB in infants was an extreme rarity. Moreover, a correlation between brain swelling and the presence of SDB could not be drawn. Our data argue strongly against the unified hypothesis and strengthen the association between SDB and NAHI in infancy.

Degos disease: a new simulator of non-accidental injury

Recent high-profile cases have made paediatricians very aware of the serious implications of either missing or wrongly diagnosing non-accidental injury. Subdural fluid collections in non-mobile infants usually represent haemorrhage caused by non-accidental injury. We report a 6-month-old male who presented to the Accident and Emergency Department of Birmingham Heartlands Hospital with bilateral subdural fluid collections and skin ulcers resembling cigarette burns. Non-accidental injury was considered to be the most likely diagnosis. However, while under observation in hospital, the child's neurological condition deteriorated with progressive cerebral infarctions, and serial photographs of the skin lesions showed failure to heal. The revised diagnosis, confirmed histologically, was Degos disease, an extremely rare and often fatal occlusive vasculopathy. The child was treated palliatively and died 8 weeks after presentation. This report informs doctors of a new simulator of non-accidental injury to be considered in infants with otherwise unexplained subdural fluid collections.

Fatal head injury in children younger than 2 years in New York City and an overview of the shaken baby syndrome

CONTEXT

Shaken baby syndrome is a controversial topic in forensic pathology. Some forensic pathologists state that shaking alone is insufficient to explain death and that an impact must have occurred even if there is no impact site on the head.

OBJECTIVE

To examine a large cohort of fatal, pediatric head injuries for patterns of specific autopsy findings and circumstances that would support or dispute pure shaking as the cause of death.

DESIGN

We retrospectively reviewed 59 deaths due to head injuries in children younger than 2 years certified in our office during a 9 year period (1998-2006). The review included autopsy, toxicology, microscopy, neuropathology, and police and investigators' reports.

RESULTS

There were 46 homicides, 8 accidents, and 1 undetermined death from blunt-impact injury of the head. In 10 (22%) of the homicides, there was no impact injury to the head, and the cause of death was certified as whiplash shaking. In 4 (40%) of these 10 deaths, there was a history of shaking. In 5 (83%) of the other 6, there was no history of any purported accidental or homicidal injury. All 8 accidental deaths had impact sites. Of the 59 deaths, 4 (6.7%) had only remote injuries (chronic subdural hematomas, remote long bone fractures) that were certified as undetermined cause and manner. These 4 deaths were excluded from the study.

CONCLUSIONS

We describe a subset of fatal, nonaccidental head-injury deaths in infants without an impact to the head. The autopsy findings and circumstances are diagnostic of a nonimpact, shaking mechanism as the cause of death. Fatal, accidental head injuries in children younger than 2 years are rare.

Cerebral traumatism with a playground rocking toy mimicking shaken baby syndrome

Shaken baby syndrome (SBS), one of the most deadly and devastating forms of child abuse, is caused by violent shaking. The combination of subdural hematoma, retinal hemorrhage, brain swelling, and diffuse axonal injury is highly typical of this syndrome and faced with these autopsy findings, induced traumatic lesions are strongly considered. However, it is known that motor-vehicle accidents and falls from great height can also produce this pattern of injury. Nevertheless, stories of arms fall, couch fall, or bumped head while the baby is being carried are generally considered incompatible with SBS. We here report a case of a 2-year-old boy presenting with all the classic autopsy findings of SBS from a playground rocking toy shaken by an older child.

Shaken baby syndrome in New Zealand, 2000-2002

AIM

To describe the epidemiology of subdural haemorrhage (SDH) in New Zealand infants.

METHODS

Prospective enrollment of all cases of infantile SDH from 2000 to 2002. Retrospective analysis of national discharge and death data for the same period.

RESULTS

Seventy-seven cases of infantile SDH were identified prospectively, and a further 49 cases retrospectively. Of these 126 cases, 92 resulted from non-birth-related trauma. Forty-eight of these were attributed to abuse and 28 to accidental injury. Sixteen cases were undetermined. The 'minimum' annual incidence of inflicted infantile SDH in New Zealand is 14.7 per 100,000 (95% confidence interval(CI) 10.8-19.4), and the 'maximum' 19.6 per 100,000 (95% CI 15.1-25.0). Among Maori, the 'minimum' is 32.5 per 100,000 (95% CI 21.4-47.3), and the 'maximum' 38.5 per 100,000 (95% CI 26.3-54.4).

CONCLUSIONS

The epidemiology of infantile subdural haemorrhage in New Zealand is similar to that described elsewhere. Non-accidental head injury is a significant child health issue in New Zealand, and the incidence is particularly high among Maori.

Lack of evidence for a causal relationship between hypoxic-ischemic encephalopathy and subdural hemorrhage in fetal life, infancy, and early childhood

It has been asserted that hypoxic-ischemic encephalopathy (HIE) with cerebral swelling in the absence of marked trauma may be responsible for subural hemorrhage in the young. As this may have considerable implications in determining both the mechanism of death and the degree of force required to cause injury in certain cases of inflicted head injury in infancy, clarification is required. A retrospective study of 82 fetuses, infants, and toddlers with proven HIE and no trauma was undertaken from forensic institutes in Australia, the United Kingdom, Germany, Denmark, and the United States. The age range was 35 weeks gestation to 3 years, with a male to female ratio of 2:1. All cases had histologically confirmed HIE. Causes of the hypoxic episodes were temporarily resuscitated sudden infant death syndrome with delayed death (N = 30), drowning (N = 12), accidental asphyxia (N = 10), intrauterine/delivery asphyxia (N = 8), congenital disease (N = 6), aspiration of food/gastric contents (N = 4), inflicted asphyxia (N = 3), epilepsy (N = 1), dehydration (N = 1), drug toxicity (N = 1), complications of prematurity (N = 1), and complications of anesthesia (N = 1). The initiating event was not determined in 4 instances. In no case was there macroscopic evidence of subdural hemorrhage. In this study no support could be given to the hypothesis that HIE in the young in the absence of trauma causes subdural hemorrhage.

Shaken baby syndrome

Before the Court of Appeal

Child maltreatment, child protection and mental health

PURPOSE OF REVIEW

This review summarizes advances in our understanding of child maltreatment and the implications thereof for physical, psychological and social development, with special emphasis on mental health aspects.

RECENT FINDINGS

Methodological problems persist. These may be related in part to an over-emphasis on type of maltreatment, to the detriment of consideration of degree and extent of maltreatment. They may also be related to inadequate application of a comprehensive model of maltreatment and its consequences. Recent studies underline the inter-relatedness and cross-over between different types of child maltreatment and family violence. Research also underlines the extent to which child maltreatment is a major public health crisis internationally. Effects are seen on physical health and development as well as mental health, and it is becoming increasingly evident that these outcomes are inextricably linked to one another. There are encouraging signs that certain interventions are effective.

SUMMARY

There is a need for a more sophisticated model of child maltreatment that includes not only degree but also the extent to which basic developmental needs are overridden when children are maltreated, and that includes children's responses to maltreatment as a mediating influence. More studies are needed of samples of children who have been maltreated in order to gain a better understanding of how maltreatment distorts the trajectory of normal development. Crucially, we need more research on intervention, including both case management and psychological treatment approaches.

Rigid-body modelling of shaken baby syndrome

Recent reassessment of the literature on the shaken baby syndrome (SBS) has revealed a lack of scientific evidence and understanding of all aspects of the syndrome. In particular, studies have been unable to clarify the mechanisms of injury, indicating that impact, rather than shaking alone, is necessary to cause the type of brain damage observed. Rigid-body modelling (RBM) was used to investigate the effect of neck stiffness on head motion and head-torso impacts as a possible mechanism of injury. Realistic shaking data obtained from an anthropometric test dummy (ATD) was used to simulate shaking. In each study injury levels for concussion were exceeded, though impact-type characteristics were required to do so in the neck stiffness study. Levels for the type of injury associated with the syndrome were not exceeded. It is unlikely that further gross biomechanical investigation of the syndrome will be able to significantly contribute to the understanding of SBS. Current injury criteria are based on high-energy, single-impact studies. Since this is not the type of loading in SBS it is suggested that their application here is inappropriate and that future studies should focus on injury mechanisms in low-energy cyclic loading.