Preventing abusive head trauma resulting from a failure of normal interaction between infants and their caregivers

Edited by Gene E. Robinson, University of Illinois at Urbana–Champaign, Urbana, IL, and approved August 7, 2012 (received for review February 14, 2012)
October 8, 2012
109 (supplement_2) 17294-17301


Head trauma from abuse, including shaken baby syndrome, is a devastating and potentially lethal form of infant physical abuse first recognized in the early 1970s. What has been less recognized is the role of the early increase in crying in otherwise normal infants in the first few months of life as a trigger for the abuse. In part, this is because infant crying, especially prolonged unsoothable crying, has been interpreted clinically as something wrong with the infant, the infant’s caregiver, or the interactions between them. Here, we review an alternative developmental interpretation, namely, that the early increase in crying is a typical behavioral development in normal infants and usually does not reflect anything wrong or abnormal. We also review evidence indicating that this normal crying pattern is the most common trigger for abusive head trauma (AHT). Together, these findings point to a conceptualization of AHT as the consequence of a failure in an otherwise common, iterative, and developmentally normal infant–caregiver interaction. They also imply that there is a window of opportunity for prevention of AHT, and potentially other forms of infant abuse, through a public health primary universal prevention strategy aimed at changing knowledge and behaviors of caregivers and society in general concerning normal development of infants and the significance of early increased infant crying. If effective, there may be important implications for prevention of infant abuse nationally and internationally.
Abusive head trauma (AHT), also known more commonly as shaken baby syndrome (SBS), is a devastating and potentially lethal form of infant physical abuse (1). The outcomes are grim. In recognized cases, AHT typically results in death or extremely damaging injuries. About 18–25% of babies who are shaken and hospitalized die (27). As many as 80% of survivors have significant lifelong brain injuries (3, 8, 9). Although currently under study, there are no published estimates of lifetime costs per victim specific to AHT. However, the conservative estimated lifetime costs per victim is $210,012 for nonfatal child maltreatment or $1,272,900 for a death from child maltreatment (in 2010 dollars) for a total estimated economic burdern in the US for one year of $124 billion (10). Given its relative severity compared to other forms of maltreatment, these per victim estimates are likely to underestimate the lifetime costs for AHT victims. Of course, the “costs” go far beyond financial considerations, and include the destruction of families and the failure of society’s moral obligation to protect defenseless infants.
Preventing child maltreatment of any kind is challenging (11) because of the lack of specific stimuli for abuse, the density and difficulties of modifying risk factors in which families of maltreated children are often embedded, and the challenges of getting appropriate supports to the families. However, the convergence of our increasing understanding of how AHT occurs, along with a developmental interpretation of early crying phenomenology in healthy infants, has led to the recognition of the role of crying as a stimulus for AHT. This brief review surveys our current understanding of AHT, the evidence for a developmental interpretation of early increased crying, and the evidence indicating that crying is the most common stimulus for AHT. Rather than being understood as a consequence of abnormal behavior, at-risk caregivers, or their interaction, AHT is better conceptualized as a tragic failure of an otherwise normal, common, iterative interaction between infants and their caregivers.
In one sense, AHT can be seen as the outcome of an early failure in social interaction that results in the ultimate destructive “biological embedding” of early social adversity, the topic of this Sackler Symposium. However, the argument posed in this paper also implies a more positive “embedding” story that is developing. As will be argued, infant crying is an ambiguous signal that can provoke positive, supportive, survival-promoting caregiving responses as well as the negative, destructive, survival-endangering caregiver responses that can result in AHT. Indeed, recent neuroimaging studies are showing that infant crying is a potent stimulator of brain activity in areas hypothesized to be involved in mammalian parenting behavior (12). Consequently, the possibility that effective prevention may be possible through shifting cultural norms about the meanings of early crying could, in principle, enhance embedding of early experience that is positive, supportive, and survival-promoting.


AHT and SBS are forms of nonaccidental inflicted injury to infants often due to violent shaking, impact to the head, or a combination of both. These injury mechanisms can result in head trauma, including subdural hematoma, diffuse axonal injury, cerebral edema, retinal hemorrhages, and sometimes fractures of the long bones or ribs, with little or no external evidence of trauma (6). Because the injury is seldom witnessed and the mechanism of injury can be broader than just shaking alone, the American Academy of Pediatrics (1) recently recommended that the phrase “abusive head trauma” be used for medical and legal purposes to avoid implying knowledge of mechanisms that could not be demonstrated, reserving the phrase “shaken baby syndrome” for advocacy and prevention purposes. SBS is a subset of AHT, which, in turn, is a subset of physical abuse in infants and young children.
Although infant abuse was recognized in the 19th century (1, 13), the first explicit causal connection between shaking and typical subdural hemorrhages was reported by pediatric neurosurgeon Norman Guthkelch in 1971 (14) and subsequently confirmed by other clinicians (1518). The relative roles of acceleration/deceleration injury; impact or blunt trauma; and secondary brain injury resulting from hypoxia, ischemia, and metabolic cascades in the clinical outcomes continue to be defined (1, 1922), but there is little debate about their potential seriousness. Estimates of incidence vary, ranging from 14 to 32 cases per 100,000 live births for infants under 1 y of age, depending on the country and whether the estimates are based on active prospective surveillance or passive surveillance (7, 2328). Although abusive head injury can occur in older children and even in adults (29), about 80% of cases occur before the age of 1 y (30). A similar pattern holds for more general serious physical abuse hospitalizations and deaths (31). There is a clear reproducible skewing of age-specific incidence of AHT, with a peak incidence in the third month (23, 28, 3234) (Fig. 1), an age-specific pattern that holds for infant abusive fractures as well (30, 35).
Fig. 1.
Age-specific number of reported cases of SBS in infants from 0 to 18 mo of age from the NCSBS Victim Database entered between January 1, 2003 and August 31, 2004. Diamonds and the solid line represent all cases irrespective of stimulus (n = 591), and squares and the broken line represent the subgroup of cases with crying reported as the stimulus (n = 166). (Reproduced with permission from ref. 33. Copyright 2007 Lippincott Williams & Wilkins, Inc.)
Perpetrators are most likely to be related males, followed by boyfriends or stepfathers, mothers, temporary caregivers, and others (1, 4, 6, 3644). Inflicted deaths are increased in households with unrelated adults rather than two biological parents but not in single-parent households without other adults (45). A remarkably constant unexplained finding is that victims are always more likely to be male than female (4, 7, 15, 23, 3739, 46, 47). Two speculations to account for this discrepancy are that there are male/female differences in some property of crying for which there is no evidence or that caregivers (particularly fathers) are more frustrated by male than female infant crying by extrapolation from the adult belief that “men do not cry, but women do,” a hypothesis that has not been investigated. Less consistent risk factors include socioeconomic status, societal and family stress, prematurity, multiple births, developmental delay, prior military service, and childhood history of abuse in the perpetrator (7, 25, 34, 44, 4852). Race and ethnicity are typically not risk factors (44, 50, 53).
A critical risk factor is the occurrence of shaking used either to calm infants and children or as a means of discipline. Studies are subject to social desirability biases against reporting. Despite these limitations, 1.9% of mothers and 3.0% of the general population in Vancouver agreed with the statement that “shaking is a good way to help a baby stop crying” (54). In Holland, 5% of parents reported shaking as a means of calming infants (55). Shaking as a means of discipline was reported for 2.6% of children less than 2 y of age in the Carolinas, and mothers reported shaking more frequently than fathers or father figures (56). This rate was 150-fold higher than the number of recognized cases of inflicted traumatic brain injury in the same states (7). Available international figures are even more disturbing. Rates of shaking children younger than the age of 2 y as a means of physical punishment were 20% or higher in 9 of 16 communities sampled in five countries, ranging up to 63% in rural Lucknow, India (57). Although some of this shaking may represent less severe “jostling,” focus groups suggested the behavior was equivalent to shaking understood as abuse (57).
A particularly dangerous feature of shaking is its unique effects on the perpetrator and the infant victim compared with other forms of infant abuse. On the one hand, the caregiver who slaps an infant experiences a stinging of the hand that might indicate he or she is acting in an inappropriate manner or has lost control, whereas shaking does not. Nor does it leave an external mark on the infant. On the other hand, an infant who is shaken typically stops crying due to having experienced a concussion-like brain injury, whereas a slap, hit, or throw against a hard object results in increased crying. Consequently, shaking reinforces a “positive feedback” cycle in which the caregiver is rewarded by improved infant behavior and lack of negative consequences for the caregiver. This feature may promote recurrent shaking episodes over time. In a chilling report of 29 perpetrator confessions, Adamsbaum et al. (37) described shaking as repeated in 55% of cases: Repeat shaking ranged from 2 to 30 times (mean of 10 times), shaking occurred daily for several weeks in 20% of cases, and shaking was repeated because it stopped crying in all cases.
Another feature of AHT is the discrepancy between the incidence of clinically recognized cases and the unmeasured burden of unrecognized cases. Less severe cases may not be brought to medical professionals and may never be diagnosed. Although not all episodes of caregiver shaking will result in clinically significant if unrecognized consequences (56), unknown numbers of infants may develop milder forms of motor dysfunction, sensory compromise, or cognitive losses. All case series have reported detecting signs of prior abuse in 30–70% of cases at the time of AHT diagnoses, implying that considerable abuse occurred without coming to clinical attention (8, 58). When they did, Jenny et al. (59) reported that 31% of cases were “missed” on first presentation to health care facilities and that 28% of the missed cases were repeat injuries following the original missed diagnosis. Coupled with the high incidence of repeated shaking as a common caregiver strategy, such observations reinforce the importance of primary and universal prevention strategies.


The frustration and anger generated by crying are universal and legendary, encapsulated in lullabies and literature from every culture [e.g., Chekhov’s story “Sleepy” (60)] and now a topic of thousands of entries on mommy blogging sites. Clinically, crying is brought to clinicians as the problem of “colic.” The implied assumption is that something is wrong or abnormal with the infant, the caregiver, or the caregiver–infant interaction. Despite a substantial literature (6163), a specific clinical definition of colic remains elusive. The most widely cited is known as Wessel’s “rule of threes” in which an infant is said to have colic if he/she cries for more than 3 h a day for more than 3 d a week for more than 3 wk (61). The most common qualitative features include an age-dependent crying pattern in which crying increases in the first few weeks and decreases in the third and fourth months, associated behaviors that include prolonged inconsolable crying bouts and a “pain facies” when crying, and crying that is unpredictable (“paroxysmal”) as to when it starts and stops (63). Clinical series have implicated organic causes in only a small proportion (under 5%) of cases (6365).
Phenomenological studies of crying in nonclinical settings in otherwise normal infants have led to a reconceptualization of early increased crying (and colic) as being a manifestation of the development of normal infants rather than a sign of something wrong in the infants or their caregivers (66). Six properties of crying, all described in infants with colic as well, have been shown to be typical and unique to the first months of life (63, 6668). Overall crying per day (fussing, crying, and inconsolable crying combined) increases weekly, peaks in the second month, and recedes to stable lower levels by the fourth or fifth month (6870), typically referred to as the “normal crying curve.” (71) The number of hours of inconsolable crying is roughly proportional to the overall crying infants do (72). Many of the crying bouts are unexpected and unpredictable, starting and stopping for no apparent reason and unrelated to feeding, wet diapers, or the environment. Approximately 5–10% of crying bouts are resistant to soothing, or inconsolable (72, 73), and the infant appears to be in pain even when he/she is not (74). Distress bouts are the longest that the infant will ever experience, lasting 40 min on average and sometimes 1 to 2 h (70, 73), with clustering in the late afternoon and evening (66, 69, 70). Before the age of 5 mo, these properties reflect infant behavioral states rather than purposeful signaling (66, 75). Later, crying is more intentional, context-specific, incorporated with signaling systems (76), and reactive in nature (71). There is high infant-to-infant variability that is continuously distributed over infants with and without colic, (66, 67) with 25% of infants crying more than 3.5 h per day and 25% crying less than 1.7 h per day (69, 70).
Numerous lines of evidence support the interpretation that these properties of early increased crying (including colic) are manifestations of normal behavioral development. First, the pattern of increased, peaking, and decreased crying has been replicated in all Western societies studied with few variations (61, 6871, 7779) and no secular trend over the past 30 y (69, 70, 77) (Fig. 2). A similar pattern and timing occur in cultures with radically different caretaking styles (78, 80, 81). This is best documented in the !Kung San hunter-gatherers (80), who maintain constant mother–infant contact, breastfeed four times an hour, and immediately respond to all frets and whimpers. Despite doing everything that should be soothing, the same increasing/decreasing pattern of crying is strongly present (80). Second, similar “distress curves” have been found in all mammalian species studied to date, including guinea pigs (82), rat pups (83), and chimpanzees (84). Third, the same distress curve occurs at 6 wk of corrected age in infants born 8 wk prematurely, implying that the crying reflects a maturational developmental pattern (85). Fourth, by comparing acoustic and diary recordings in infants with and without colic, crying that was identified as colic by parents occurred in all groups proportionately to overall crying amounts, had the same distribution throughout the day, and did not differ from the noncolic crying and fussing periods of infants without colic (72). Fifth, infants with colic have as good a developmental outcome as infants without colic (86). Finally, all the typical features of colic (63), including the unpredictable starting and stopping of crying bouts, can be explained on the basis of nonpathological mechanisms governing behavior in normal infants (66).
Fig. 2.
Crying amounts and patterns from three North American studies illustrating the age-related crying curve and absence of a secular trend. Triangles represent data from Brazelton (69), circles represent data from Hunziker and Barr (70), and diamonds represent data from Kramer et al. (77). (Reproduced from ref. 32. Copyright 2005 Elsevier Ltd.)
Evidence such as this has contributed to the reconceptualization of the early increases and decreases in infant crying as a manifestation of the development of normal infants (66). If infants have an organic condition, they may cry even more because the disease state may increase the amount of crying still further, but this is usually associated with other symptoms in addition to the crying itself (62). Otherwise, the clinical significance of early crying and colic is largely a function of how crying is perceived and responded to by caregivers (73, 87, 88). Although the audible character of the infant’s distress may contribute to caregivers’ interpretations, it appears that the properties of daily crying bouts, especially the prolonged, hard-to-soothe, unpredictable, and unexplained bouts, are what make caregivers feel helpless and guilty in the face of the alarming and uncontrollable crying of their infants (72). These prolonged bouts are almost unique to the first few months of life (72, 73, 89). Maximum bout lengths of unsoothable crying are much more strongly and significantly associated with caregiver self-ratings of frustration than with overall frequency or duration per day of crying or fussing (90). The frustration is understandable, because nothing the caregiver can do appears to help. However, these unsoothable bouts most often are not, contrary to popular opinion, an intentional signal of the infant’s unmet needs or the caregiver’s ability (or inability) to soothe but rather a manifestation of the organization of the infant’s behavioral states (crying, awake and alert, and sleeping) (66, 75). The behavioral states of infants manifest properties of a well-organized nonlinear dynamic system, such that the behavioral states are resistant to change unless they are in a transitional stage (“ready” to change state) (66, 91, 92). However, because there is nothing in the sound of the crying or behavior of the infant that allows caregivers to know when the crying state is transitional, the very same soothing efforts may, unpredictably, be effective some of the time but not at others.
Despite being a manifestation of normal infant development, understanding why increased and unsoothable crying occurs that is so frustrating to caregivers is a challenge. This has resulted in work on the positive survival value of early crying in the evolutionary history of humans and other species, including its roles in ensuring nutrition, protection from predators, and early formation of attachment relationships (9397). As with most evolutionarily influenced behaviors, whether crying functions positively or negatively for the individual depends on the context in which it is expressed (98). Increased isolation of mothers due to short maternity leaves, nuclear families, and separated mother and infant living arrangements are likely to increase the stress due to crying in contemporary societies. However, important evolutionary questions concerning its role in survival and reproductive success remain [reviewed by Soltis (93)].

Crying as the Stimulus for AHT/SBS and Infant Physical Abuse Generally

The possibility of crying as a stimulus for abuse was recognized in many early case reports. In a seminal article, Kempe (99) astutely described a growing cascade of frustration and anger when crying was inconsolable: “The baby cries and the mother feeds it, it cries more, the mother changes it, it still cries, and there comes that dreadful moment in every parent’s life when love and desire to care for the child is mixed with incredible disappointments, anger, and even hate. It is surprising not that there are so many battered babies, but that there are so few.” Crying continued to be noted as a stimulus for AHT in anecdotal case series (1417, 100, 101) and in later, more systematic studies (40, 55). As implied by Kempe’s observation (99), crying is not simply an aversive stimulus; rather, it functions both to attract positive caregiving responses (feeding and changing) and to provoke frustration, anger, and abuse, especially when inconsolable. In contrast to the specific hunger and separation cries described in some animal species (102), the evidence that there are acoustically distinct cry “types” in human infants is not strong. Murray (96) and others (93, 103) argue that human infant crying is a graded signal that varies in intensity, pitch, and loudness but is not distinctively different as a function of the stimulus. This lack of signal specificity contributes to caregivers not knowing what the crying “means,” such that it may provoke either altruistic (helping the baby) or egoistic (protecting the listener) responses (96). In addition, excessive prolonged crying can transform a caregiver’s initial motivation from altruistic to egoistic, resulting in the extreme in abuse (96, 104).
When acoustic analyses of cry signals became available, they stimulated intense study about which acoustic features influence perceived meaning of cries (105108). In studies of normal crying as the stimulus (rather than elicited pain or atypical cries), three features characterized these reports. First, acoustic properties related to affective and infant care responses were variable and often not replicated, although fundamental frequency, cry duration, dysphonation, and pauses received the most attention (105, 106, 108113). Second, almost all studies used single cries; brief segments (10–15 s), or, at most (rarely), 4 min (106, 112115) of crying, such that responses were based on short segments taken out of context (106, 116). Third, only one study (113) related continuous acoustic changes in spontaneous crying to concurrent adult ratings of infant distress (for 4 min). A few studies have reported that abusive as well as comparison parents perceived cries with high-pitched or hyperphonated cries as more sick-sounding, distressing, arousing, and urgent, and more likely to be associated with future abuse of the infant (117119). However, as a general rule, it remains unclear whether acoustic characteristics, such as high-pitched or otherwise abnormal crying, are critical precipitating factors in abuse (93) rather than crying bout characteristics, such as duration, frequency, and bout length (66, 90).
Anecdotal reports of the role of crying in case histories of abuse are suggestive but inevitably subject to potential bias because of guilt and possible legal implications. To address that problem, the characteristic developmental timing of the normal crying curve has been used to assess the probable importance of crying as a stimulus on a population basis. The hypothesis was that if crying is a significant trigger, the age-specific incidence curve of AHT/SBS should have a similar beginning, shape, and peak as the age-specific pattern of early infant crying (Fig. 2). This hypothesis was confirmed using cases from discharge data abstracts from California hospitals between 1996 and 2000 for which the International Classification of Diseases 9 Clinical Modification code for SBS (995.55) was assigned. The curve of age-specific incidence began to increase at 2–3 wk, had a clear peak at 10–13 wk, and declined to baseline by about 36 wk of age (32). This was replicated in an analysis of cases in the victim database of the National Center on Shaken Baby Syndrome (NCSBS) populated by publicly reported cases occurring in 2003 and 2004 (33) (Fig. 1). Although these samples were subject to different potential reporting biases, the age-specific incidence curve from the NCSBS sample was essentially identical to that of the California sample. Crying was specifically reported as the stimulus in a subgroup of the NCSBS victim database cases. For those cases, the age-specific incidence curve had exactly the same characteristics (Fig. 1). Convergent findings of the same age-specific pattern were also reported in Scotland (23) and in Estonia (34). Indeed, the occurrence of infant abusive fractures has similar age-specific characteristics (30). An intriguingly consistent finding is that the peak of infant crying occurs at about 6 wk of age (6971), whereas the AHT/SBS or infant abuse incidences peak in the third month of life (23, 30, 3234). The most likely reason for the “delay” in the abuse compared with the crying peaks is the consistent evidence of repeated shaking or abusive episodes in many cases before the abusive incident that resulted in the diagnosis (37, 58).
Perpetrator confessions have converged in supporting the role of crying as a stimulus for AHT and infant physical abuse. In the important series by Adamsbaum et al. (37), crying was the reported stimulus in 63% of the cases, similar to other series of reported confessions (38, 39, 43). The convergent anecdotal, epidemiological, and perpetrator confession evidence for the role of crying as a stimulus has led to its incorporation into the recommendations for prevention of the American Academy of Pediatrics (6) and the Canadian Joint Statement on SBS (120).

Window of Opportunity for Prevention

There is no controversy that child abuse should be prevented, but there are considerable challenges to defining and instituting effective strategies, programs, and policies (11). For AHT, the increasing recognition of the clinical syndrome, its epidemiology, and its devastating consequences (1, 7, 44, 50, 121) has increased efforts to find effective preventive options. In contrast to most forms of child maltreatment, AHT meets a number of criteria that make it a candidate for prevention through a public health strategy. First, the outcomes are undoubtedly severe and, simply from the perspective of costs of initial hospitalization, financially substantial (10). Second, this form of infant abuse has a clear risk behavior (caregiver shaking) and stimulus (crying), permitting specific targeting of prevention messages. Third, evidence is emerging that it is preventable. An observational study in upper New York state by Dias et al. (2) reported a 47% reduction in cases (41.5 to 22.2 cases per 100,000 live births) when comparing pre- and postimplementation periods of a parent education program at a newborn’s birth. The principal program constituents were the delivery by nurses of information about the dangers of violent infant shaking, asking parents to watch a videotape discussing the dangers of shaking and ways to handle persistent crying, educational posters on the wards, and voluntary signing of a commitment statement affirming receipt and understanding of the materials. A small replication using similar materials reported a 75% reduction in incidence (122).
The salience of crying as a stimulus has encouraged approaches that focus on educating parents about the properties of early infant crying. The NCSBS (123) has developed a booklet and digital video disk (DVD) called the Period of PURPLE Crying that teaches parents about the normalcy of early crying properties and the dangers of shaking. The NCSBS program includes three “doses” of prevention: Dose 1 approximates the New York program but has nurses focus on the properties of normal newborn crying as well as the dangers of shaking, provides each family a copy of the materials to take home to review when crying occurs and to share with other caregivers, and may or may not use a commitment statement; dose 2 is a reinforcement of the messages pre- and/or postdelivery by other health care providers or public health workers; and dose 3 is a public education campaign to educate society at large about infant crying and the dangers of shaking. In two randomized controlled trials, these materials significantly increased knowledge about crying properties and changed behaviors relevant to preventing shaking (54, 124). The program exploits the desire of all parents of newborns to know about infant crying, even if they are reticent to hear about shaking and abuse. An additional DVD (Crying, Soothing, and Coping: Doing What Comes Naturally) has been added that is focused specifically on soothing techniques. In another intervention focused on crying (Take 5 Plan for Crying), pediatric residents successfully increased maternal knowledge about infant crying and the dangers of shaking at newborn hospital discharge (125). Whether these two programs are effective in reducing AHT has not yet been demonstrated.
Importantly, these approaches capitalize on a set of assumptions that are different from most prevention programs. Primarily, AHT is conceptualized as the outcome of a failure of interaction between normal caregivers and the development of infant crying in normal infants. Despite being a strong elicitor of positive caregiving interactions, crying, especially when prolonged and inconsolable, can stimulate frustration and anger in the caregiver and negative responses to the infant up to and including shaking and abuse. Although shaking or abuse could occur, and could occur more frequently, in caregivers embedded in recognized sets of risk factors or in infants with atypical cries, the process that leads from crying to shaking or abuse can occur with any caregiver and any crying infant if the caregiver’s individual tolerance for an infant’s crying is exceeded.
Such assumptions have a number of practical implications for effective prevention. Prevention strategies need to be primary (delivered before occurrence) and universal (delivered to all parents of newborns and not targeted at just some parents) (11). Although not all shaking will be clinically significant for the infant, the dangers of hypothesized, although not yet demonstrated, subclinical pathology, and especially repeated shaking, because of the positive feedback cycle mandate intervention before any shaking or abuse occurs. In addition, the age-dependent clustering in the early months associated with increased crying clearly targets the perinatal period as critical for primary prevention. Universality is a prerequisite because risk factors may be absent. Even if parents do not shake their infant, transient caregivers may do so. If transient caregivers believe that good care is inconsistent with crying (especially when they are employed to “take care” of an infant), they may experience more pressure than parents to keep an infant from crying. Coupled with the well-documented difficulties in recognition and reporting typical of AHT (59) and of child maltreatment generally (126), primary and universal strategies are essential for effective prevention. For this reason, providing prevention messages in the context of delivery of an infant has been targeted as the most likely, and perhaps the only, way to be able to access all parents of newborn infants. Furthermore, mothers are the most likely “gatekeepers” for deciding whether others (and if so, who) might help them care for their infant. Specific efforts to target fathers (who might not be present on the maternity ward when the materials are delivered) and teenagers (who are likely temporary caregivers and future parents themselves) are much discussed but have not been evaluated to date. However, in all extant programs, sharing of the information with other caregivers is a high-priority message.
A second implication is that universal public health messages have to be attractive, consistent, meaningful, and positive for multiple caregiving cultures and consistent with professional practice norms in the health sector. For the former, recommendations, such as putting the baby down and walking away if the crying is too frustrating, may be more acceptable in some cultures than others. For the latter, messages need to be consistent with infant feeding, safe sleep, and breastfeeding recommendations. They must also avoid recommendations that are in flux and sometimes conflicting among professional groups, as is the case for swaddling (127130). If messages contradict deeply held cultural norms or practices that, even if controversial, have a committed following among some health professionals, the messages will not be transmitted regardless of how clear, accurate, helpful, and preventive they are.
A third implication is that to the extent that shaking is a normative component of caregiving either for soothing or discipline, the public health challenge may be more widespread and urgent than previously imagined. Current evidence often does not sufficiently distinguish between rates of milder nondangerous jostling or a small, single shake of the shoulders compared with more dangerous vigorous or violent shaking. Nevertheless, it is easy to imagine how such behaviors could escalate to repetitive, violent, and abusive shaking in the face of unresponsive, inconsolable crying. Because mental retardation, learning deficits, and behavior problems are outcomes of AHT that come to medical attention (131, 132), the burden from clinically undetected shaking episodes secondary to typical caregiving could be a leading cause of mental retardation of unknown etiology (range: 19–90% depending on the series) (133137) and of infant morbidity and mortality globally (138). Reported rates of “harsh physical punishment” exceed 14%, or 39% if hitting with an object is included (57). It would not be surprising if a high rate of undetected abusive shaking that is less salient to caregivers or physicians is a significant source of unrecognized harm to infant and child development on a global scale.


AHT, or SBS, is an individual, family, and societal tragedy of devastating proportions. In a large majority of cases, shaking is triggered by the normal increased early crying of healthy newborns now recognized as a behavioral universal of infancy. The process leading to shaking can occur with any infant–caregiver dyad in the absence of abnormalities in the infant or of the caregiver. This recent understanding of the normality of infant crying and the failure of otherwise normal caregiver–infant interaction leading to shaking and abuse has provided the conceptual and empirical core for the creation of evidence-based prevention efforts to educate parents and society in general. Since shaking and abuse can occur in the absence of risk factors or abnormalities in infants or their caregivers, the basic rationale for implementation of these prevention efforts is that they be primary and universal in scope. Although the extent to which less violent, and especially repeated, shaking can lead to the development of mental retardation, learning difficulties, or behavioral problems is still unknown, the apparently high rates of shaking as a typical caregiving behavior coupled with variable awareness of its potential dangers, especially internationally, imply that there exists a critically important public health challenge of preventing these tragic failures. The evidence is compelling that such failures happen, but our understanding of how caregivers move from crying to abuse remains rudimentary. As our understanding of inhibitors and enhancers of shaking and abuse grows, our ability to prevent these tragedies should too. Meanwhile, although not yet definitive, early prevention efforts targeting caregiver–infant interactions around early crying are encouraging signs that prevention can work and contribute to giving otherwise normal infants a “good start” in life.


This work was supported by funds from the Canada Research Chair in Community Child Health Research and the Child and Family Research Institute (to R.G.B.).


CW Christian, R Block, Abusive head trauma in infants and children. Pediatrics; Committee on Child Abuse and Neglect; American Academy of Pediatrics 123, 1409–1411 (2009).
MS Dias, et al., Preventing abusive head trauma among infants and young children: A hospital-based, parent education program. Pediatrics 115, e470–e477 (2005).
WJ King, M MacKay, A Sirnick, Shaken baby syndrome in Canada: Clinical characteristics and outcomes of hospital cases. CMAJ; Canadian Shaken Baby Study Group 168, 155–159 (2003).
SP Starling, JR Holden, C Jenny, Abusive head trauma: The relationship of perpetrators to their victims. Pediatrics 95, 259–262 (1995).
SP Starling, Child Maltreatment: A Clinical Guide and Reference, eds Giardino AP, Alexander R (GW Medical Publishing, St. Louis), pp 37–62. (2005).
; American Academy of Pediatrics: Committee on Child Abuse and Neglect, Shaken baby syndrome: Rotational cranial injuries—Technical report. Pediatrics 108, 206–210 (2001).
HT Keenan, et al., A population-based study of inflicted traumatic brain injury in young children. JAMA 290, 621–626 (2003).
L Ewing-Cobbs, et al., Neuroimaging, physical, and developmental findings after inflicted and noninflicted traumatic brain injury in young children. Pediatrics 102, 300–307 (1998).
C Bonnier, et al., Neuroimaging of intraparenchymal lesions predicts outcome in shaken baby syndrome. Pediatrics 112, 808–814 (2003).
X Fang, DS Brown, CS Florence, JA Mercy, The economic burden of child maltreatment in the United States and implications for prevention. Child Abuse and Neglect 36, 156–165 (2012).
HL Macmillan, et al., Interventions to prevent child maltreatment and associated impairment. Lancet 373, 250–266 (2009).
JE Swain, JP Lorberbaum, S Kose, L Strathearn, Brain basis of early parent-infant interactions: Psychology, physiology, and in vivo functional neuroimaging studies. J Child Psychol Psychiatry 48, 262–287 (2007).
AJ Roche, G Fortin, J Labbé, J Brown, D Chadwick, The work of Ambroise Tardieu: The first definitive description of child abuse. Child Abuse Negl 29, 325–334 (2005).
AN Guthkelch, Infantile subdural haematoma and its relationship to whiplash injuries. BMJ 2, 430–431 (1971).
J Caffey, On the theory and practice of shaking infants. Its potential residual effects of permanent brain damage and mental retardation. Am J Dis Child 124, 161–169 (1972).
J Caffey, The whiplash shaken infant syndrome: Manual shaking by the extremities with whiplash-induced intracranial and intraocular bleedings, linked with residual permanent brain damage and mental retardation. Pediatrics 54, 396–403 (1974).
S Ludwig, M Warman, Shaken baby syndrome: A review of 20 cases. Ann Emerg Med 13, 104–107 (1984).
AC Duhaime, et al., The shaken baby syndrome. A clinical, pathological, and biomechanical study. J Neurosurg 66, 409–415 (1987).
CZ Cory, BM Jones, Can shaking alone cause fatal brain injury? A biomechanical assessment of the Duhaime shaken baby syndrome model. Med Sci Law 43, 317–333 (2003).
AK Ommaya, W Goldsmith, L Thibault, Biomechanics and neuropathology of adult and paediatric head injury. Br J Neurosurg 16, 220–242 (2002).
RN Ichord, et al., Hypoxic-ischemic injury complicates inflicted and accidental traumatic brain injury in young children: The role of diffusion-weighted imaging. J Neurotrauma 24, 106–118 (2007).
H Bayir, PM Kochanek, VE Kagan, Oxidative stress in immature brain after traumatic brain injury. Dev Neurosci 28, 420–431 (2006).
KM Barlow, RA Minns, Annual incidence of shaken impact syndrome in young children. Lancet 356, 1571–1572 (2000).
C Hobbs, AM Childs, J Wynne, J Livingston, A Seal, Subdural haematoma and effusion in infancy: An epidemiological study. Arch Dis Child 90, 952–955 (2005).
KD Ellingson, JM Leventhal, HB Weiss, Using hospital discharge data to track inflicted traumatic brain injury. Am J Prev Med 34, S157–S162 (2008).
P Kelly, B Farrant, Shaken baby syndrome in New Zealand, 2000-2002. J Paediatr Child Health 44, 99–107 (2008).
S Bennett, et al., Head injury secondary to suspected child maltreatment: Results of a prospective Canadian national surveillance program. Child Abuse Negl 35, 930–936 (2011).
T Fujiwara, RG Barr, R Brant, F Rajabali, I Pike, Using international classification of diseases, 10th edition, codes to estimate abusive head trauma in children. Am J Prev Med 43, 215–220 (2012).
DJ Pounder, Shaken adult syndrome. Am J Forensic Med Pathol 18, 321–324 (1997).
JM Leventhal, KD Martin, AG Asnes, Fractures and traumatic brain injuries: Abuse versus accidents in a US database of hospitalized children. Pediatrics 126, e104–e115 (2010).
JM Leventhal, KD Martin, JR Gaither, Using US data to estimate the incidence of serious physical abuse in children. Pediatrics 129, 458–464 (2012).
RG Barr, RB Trent, J Cross, Age-related incidence curve of hospitalized Shaken Baby Syndrome cases: Convergent evidence for crying as a trigger to shaking. Child Abuse Negl 30, 7–16 (2006).
C Lee, RG Barr, N Catherine, A Wicks, Age-related incidence of publicly reported shaken baby syndrome cases: Is crying a trigger for shaking? J Dev Behav Pediatr 28, 288–293 (2007).
I Talvik, RC Alexander, T Talvik, Shaken baby syndrome and a baby’s cry. Acta Paediatr 97, 782–785 (2008).
JM Leventhal, KD Martin, AG Asnes, Incidence of fractures attributable to abuse in young hospitalized children: Results from analysis of a United States database. Pediatrics 122, 599–604 (2008).
TM Kajese, et al., Characteristics of child abuse homicides in the state of Kansas from 1994 to 2007. Child Abuse Negl 35, 147–154 (2011).
C Adamsbaum, S Grabar, N Mejean, C Rey-Salmon, Abusive head trauma: Judicial admissions highlight violent and repetitive shaking. Pediatrics 126, 546–555 (2010).
D Biron, D Shelton, Perpetrator accounts in infant abusive head trauma brought about by a shaking event. Child Abuse Negl 29, 1347–1358 (2005).
SP Starling, et al., Analysis of perpetrator admissions to inflicted traumatic brain injury in children. Arch Pediatr Adolesc Med 158, 454–458 (2004).
AL Brewster, et al., Victim, perpetrator, family, and incident characteristics of 32 infant maltreatment deaths in the United States Air Force. Child Abuse Negl 22, 91–101 (1998).
S Lazoritz, S Baldwin, N Kini, The Whiplash Shaken Infant Syndrome: Has Caffey’s syndrome changed or have we changed his syndrome? Child Abuse Negl 21, 1009–1014 (1997).
HT Keenan, MA Nocera, DK Runyan, Race matters in the prosecution of perpetrators of inflicted traumatic brain injury. Pediatrics 121, 1174–1180 (2008).
EG Flaherty, Analysis of caretaker histories in abuse: Ccomparing initial histories with subsequent confessions. Child Abuse Negl 30, 789–798 (2006).
HT Keenan, Child Abuse and Neglect: Diagnosis, Treatment, and Evidence, ed Jenny C (Saunders, St. Louis), pp 35–38. (2011).
PG Schnitzer, BG Ewigman, Child deaths resulting from inflicted injuries: Household risk factors and perpetrator characteristics. Pediatrics 116, e687–e693 (2005).
S Jayawant, et al., Subdural haemorrhages in infants: Population based study. BMJ 317, 1558–1561 (1998).
KW Feldman, et al., The cause of infant and toddler subdural hemorrhage: A prospective study. Pediatrics 108, 636–646 (2001).
RA Minns, PA Jones, JYQ Mok, Incidence and demography of non-accidental head injury in southeast Scotland from a national database. Am J Prev Med 34, S126–S133 (2008).
HT Keenan, SW Marshall, MA Nocera, DK Runyan, Increased incidence of inflicted traumatic brain injury in children after a natural disaster. Am J Prev Med 26, 189–193 (2004).
KP Hymel, K Deye, Child Abuse and Neglect: Diagnosis, Treatment, and Evidence, ed Jenny C (Saunders, St. Louis), pp 349–358. (2011).
ED Rentz, et al., Effect of deployment on the occurrence of child maltreatment in military and nonmilitary families. Am J Epidemiol 165, 1199–1206 (2007).
B Gillham, et al., Unemployment rates, single parent density, and indices of child poverty: Their relationship to different categories of child abuse and neglect. Child Abuse Negl 22, 79–90 (1998).
SH Sinal, et al., Is race or ethnicity a predictive factor in Shaken Baby Syndrome? Child Abuse Negl 24, 1241–1246 (2000).
RG Barr, et al., Do educational materials change knowledge and behaviour about crying and shaken baby syndrome? A randomized controlled trial. CMAJ 180, 727–733 (2009).
SA Reijneveld, MF van der Wal, E Brugman, RA Sing, SP Verloove-Vanhorick, Infant crying and abuse. Lancet 364, 1340–1342 (2004).
AD Theodore, et al., Epidemiologic features of the physical and sexual maltreatment of children in the Carolinas. Pediatrics 115, e331–e337 (2005).
DK Runyan, et al., International variations in harsh child discipline. Pediatrics 126, e701–e711 (2010).
R Alexander, L Crabbe, Y Sato, W Smith, T Bennett, Serial abuse in children who are shaken. Am J Dis Child 144, 58–60 (1990).
C Jenny, KP Hymel, A Ritzen, SE Reinert, TC Hay, Analysis of missed cases of abusive head trauma. JAMA 281, 621–626 (1999).
A Chekhov Anton Chekhov: Later Short Stories, 1888-1903 (Modern Library, New York), pp. 3–7 (1999).
MA Wessel, JC Cobb, EB Jackson, GS Harris, AC Detwiler, Paroxysmal fussing in infancy, sometimes called colic. Pediatrics 14, 421–435 (1954).
S Ghosh, RG Barr Pediatric Gastrointestinal Disease, eds WA Walker, et al. (BC Decker, Hamilton, ON, Canada), pp. 210–224 (2004).
SM Gormally, RG Barr, Of clinical pies and clinical clues: Proposal for a clinical approach to complaints of early crying and colic. Ambul Child Health 3, 137–153 (1997).
AR Miller, RG Barr, Infantile colic. Is it a gut issue? Pediatr Clin North Am 38, 1407–1423 (1991).
SB Freedman, N Al-Harthy, J Thull-Freedman, The crying infant: Diagnostic testing and frequency of serious underlying disease. Pediatrics 123, 841–848 (2009).
RG Barr Handbook of Developmental Psychopathology, eds AJ Sameroff, M Lewis, SM Miller (Kluwer Academic/Plenum, New York), pp. 327–350 (2000).
RG Barr Encyclopedia on Early Childhood Development, eds RE Tremblay, RG Barr, RD Peters (Centre of Excellence for Early Childhood Development, Montreal, QC, Canada), pp. 1–10, Available at (2006).
I St James-Roberts, T Halil, Infant crying patterns in the first year: Normal community and clinical findings. J Child Psychol Psychiatry 32, 951–968 (1991).
TB Brazelton, Crying in infancy. Pediatrics 29, 579–588 (1962).
UA Hunziker, RG Barr, Increased carrying reduces infant crying: A randomized controlled trial. Pediatrics 77, 641–648 (1986).
RG Barr, The normal crying curve: What do we really know? Dev Med Child Neurol 32, 356–362 (1990).
IS James-Roberts, S Conroy, K Wilsher, Bases for maternal perceptions of infant crying and colic behaviour. Arch Dis Child 75, 375–384 (1996).
RG Barr, JA Paterson, LM MacMartin, L Lehtonen, SN Young, Prolonged and unsoothable crying bouts in infants with and without colic. J Dev Behav Pediatr 26, 14–23 (2005).
BP White, MR Gunnar, MC Larson, B Donzella, RG Barr, Behavioral and physiological responsivity, sleep, and patterns of daily cortisol production in infants with and without colic. Child Dev 71, 862–877 (2000).
RG Barr, Early infant crying as a behavioral state rather than a signal. Behav Brain Sci 27, 460 (2004).
GE Gustafson, JA Green, Developmental coordination of cry sounds with visual regard and gestures. Infant Behav Dev 14, 51–57 (1991).
MS Kramer, et al., Pacifier use, early weaning, and cry/fuss behavior: A randomized controlled trial. JAMA 286, 322–326 (2001).
M Alvarez, I St James-Roberts, Infant fussing and crying patterns in the first year in an urban community in Denmark. Acta Paediatr 85, 463–466 (1996).
I St James-Roberts, I Plewis, Individual differences, daily fluctuations, and developmental changes in amounts of infant waking, fussing, crying, feeding and sleeping. Child Dev 67, 2527–2540 (1996).
RG Barr, M Konner, R Bakeman, L Adamson, Crying in! Kung San infants: A test of the cultural specificity hypothesis. Dev Med Child Neurol 33, 601–610 (1991).
I St James-Roberts, J Bowyer, S Varghese, J Sawdon, Infant crying patterns in Manali and London. Child Care Health Dev 20, 323–337 (1994).
TF Pettijohn, Attachment and separation distress in the infant guinea pig. Dev Psychobiol 12, 73–81 (1979).
MA Hofer, B Hopkins, RG Barr, JA Green, GE Gustafson New Evidence on Unexplained Early Infant Crying: Its Origins, Nature and Management, eds RG Barr, I St James-Roberts, MR Keefe (Johnson & Johnson, New Brunswick, NJ), pp. 55–128 (2001).
KA Bard Crying as a Sign, a Symptom, and a Signal: Clinical, Emotional, and Developmental Aspects of Infant and Toddler Crying, eds RG Barr, B Hopkins, JA Green (Mac Keith Press, London), pp. 157–175 (2000).
RG Barr, S-J Chen, B Hopkins, T Westra, Crying patterns in preterm infants. Dev Med Child Neurol 38, 345–355 (1996).
L Lehtonen, S Gormally, RG Barr Crying as a Sign, a Symptom, and a Signal: Clinical, Emotional, and Developmental Aspects of Infant and Toddler Crying, eds RG Barr, B Hopkins, J Green (Mac Keith Press, London), pp. 67–95 (2000).
MF van der Wal, DC van den Boom, H Pauw-Plomp, GA de Jonge, Mothers’ reports of infant crying and soothing in a multicultural population. Arch Dis Child 79, 312–317 (1998).
MF van der Wal, M van Eijsden, GJ Bonsel, Stress and emotional problems during pregnancy and excessive infant crying. J Dev Behav Pediatr 28, 431–437 (2007).
I St James-Roberts, S Conroy, K Wilsher, Clinical, developmental and social aspects of infant crying and colic. Early Dev Parent 4, 177–189 (1995).
T Fujiwara, RG Barr, R Brant, M Barr, Infant distress at five weeks of age and caregiver frustration J Pediatr 159:425–430.e1–2. (2011).
RG Barr, P Beek, N Calinoiu Non-Linear Developmental Processes, eds GJP Savelsbergh, HLJ van der Maas, PLC van Geert (Royal Netherlands Academy of Arts and Sciences, Amsterdam), pp. 15–37 (1999).
PH Wolff A Dynamic Systems Approach to Development: Applications, eds LB Smith, E Thelen (MIT Press, Cambridge, MA), pp. 189–208 (1993).
J Soltis, The signal functions of early infant crying. Behav Brain Sci 27, 443–458, discussion 459–490 (2004).
J Bowlby Attachment and Loss (Basic Books, New York, 1969).
V Lummaa, T Vuorisalo, RG Barr, L Lehtonen, Why cry? Adaptive significance of intensive crying in human infants. Evol Hum Behav 19, 193–202 (1998).
AD Murray, Infant crying as an elicitor of parental behavior: An examination of two models. Psychol Bull 86, 191–215 (1979).
RG Barr Evolutionary Medicine, eds WR Trevathan, EO Smith, JJ McKenna (Oxford Univ Press, New York), pp. 27–51 (1999).
SB Hrdy Mother Nature: A History of Mothers, Infants, and Natural Selection (Pantheon Books, New York, 1999).
CH Kempe, Paediatric implications of the battered baby syndrome. Arch Dis Child 46, 28–37 (1971).
J Weston The Battered Child, eds R Helfer, C Kempe (Univ of Chicago Press, Chicago), pp. 77–100 (1968).
LJ Dykes, The whiplash shaken infant syndrome: What has been learned? Child Abuse Negl 10, 211–221 (1986).
JD Newman, Vocal communication and the triune brain. Physiol Behav 79, 495–502 (2003).
GE Gustafson, RM Wood, JA Green Crying as a Sign, a Symptom, and a Signal: Clinical, Emotional, and Developmental Aspects of Infant and Toddler Crying, eds RG Barr, B Hopkins, JA Green (Mac Keith Press, London), pp. 8–22 (2000).
ML Hoffman, Developmental synthesis of affect and cognition and its implications for altruistic motivation. Dev Psychol 11, 607–622 (1975).
LL LaGasse, AR Neal, BM Lester, Assessment of infant cry: Acoustic cry analysis and parental perception. Ment Retard Dev Disabil Res Rev 11:83–93. (2005).
DM Zeifman, Acoustic features of infant crying related to intended caregiving intervention. Infant Child Dev 13, 111–122 (2004).
JA Green, GE Gustafson, Crying: Multiple determinants of perceived meaning. New Evidence on Unexplained Early Infant Crying: Its Origins, Nature and Management, eds RG Barr, I St James-Roberts, MR Keefe (Johnson & Johnson, New Brunswick, NJ), pp. 105–120 (2001).
JA Green, JR Irwin, GE Gustafson Crying as a Sign, a Symptom, and a Signal: Clinical, Emotional and Developmental Aspects of Infant and Toddler Crying, eds RG Barr, B Hopkins, JA Green (Mac Keith Press, London), pp. 137–156 (2000).
PS Zeskind, A Wilhite, TR Marshall, Infant cry as a graded signal: Experimental modifications of durations of pauses and expiratory sounds alter mothers' perceptions. Early Dev Parent 2, 99–105 (1993).
PS Zeskind, L Klein, TR Marshall, Adults’ perceptions of experimental modifications of durations of pauses and expiratory sounds in infant crying. Dev Psychol 28, 1153–1162 (1992).
GE Gustafson, JA Green, On the importance of fundamental frequency and other acoustic features in cry perception and infant development. Child Dev 60, 772–780 (1989).
RM Wood, GE Gustafson, Infant crying and adults’ anticipated caregiving responses: Acoustic and contextual influences. Child Dev 72, 1287–1300 (2001).
RM Wood, Changes in cry acoustics and distress ratings while the infant is crying. Infant Child Dev 18, 163–177 (2009).
DM Zeifman, Predicting adult responses to infant distress: Adult characteristics associated with perceptions, emotional reactions, and timing of intervention. Infant Ment Health J 24, 597–612 (2003).
G Wiedenmann, D Todt, Discrete responses of adult subjects during exposure to infant cry sequences. Early Child Dev Care 65, 179–188 (1990).
B Hopkins Crying as a Sign, a Symptom, and a Signal: Clinical, Emotional, and Developmental Aspects of Infant and Toddler Crying, eds RG Barr, B Hopkins, J Green (Mac Keith Press, London), pp. 176–209 (2000).
PS Zeskind, EA Shingler, Child abusers’ perceptual responses to newborn infant cries varying in pitch. Infant Behav Dev 14, 335–347 (1991).
A Frodi, M Senchak, Verbal and behavioral responsiveness to the cries of atypical infants. Child Dev 61, 76–84 (1990).
A Frodi, Infant Crying: Theoretical and Research Perspectives, eds Lester B, Boukydis Z (Plenum, New York), pp 263–277. (1985).
; Canadian Association of Chiefs of Policeet al., Joint statement on shaken baby syndrome. Paediatr Child Health (Oxford) 6, 663–667 (2001).
M Dias, Child Abuse and Neglect: Diagnosis, Treatment, and Evidence, ed Jenny C (Saunders, St. Louis), pp 364–372. (2011).
RL Altman, et al., Parent education by maternity nurses and prevention of abusive head trauma. Pediatrics 128, e1164–e1172 (2011).
Barr RG and the National Center on Shaken Baby Syndrome. The Period of PURPLE Crying (The National Center on Shaken Baby Syndrome, Farmington, UT).
RG Barr, et al., Effectiveness of educational materials designed to change knowledge and behaviors regarding crying and shaken-baby syndrome in mothers of newborns: A randomized, controlled trial. Pediatrics 123, 972–980 (2009).
K Bechtel, et al., Impact of an educational intervention on caregivers’ beliefs about infant crying and knowledge of shaken baby syndrome. Acad Pediatr 11:481–486. (2011).
R Gilbert, et al., Recognising and responding to child maltreatment. Lancet 373, 167–180 (2009).
PS Blair, et al., Hazardous cosleeping environments and risk factors amenable to change: Case-control study of SIDS in south west England. BMJ 339, b3666 (2009).
CT Price, RM Schwend, Improper swaddling a risk factor for developmental dysplasia of hip. American Academy of Pediatrics News 32:11. (2011).
RY Moon, SIDS and other sleep-related infant deaths: Expansion of recommendations for a safe infant sleeping environment. Pediatrics; Task Force on Sudden Infant Death Syndrome 128, e1341–e1367 (2011).
BT Thach, T Bradley, Does swaddling decrease or increase the risk for sudden infant death syndrome? J Pediatr 155, 461–462 (2009).
HT Keenan, SR Hooper, CE Wetherington, M Nocera, DK Runyan, Neurodevelopmental consequences of early traumatic brain injury in 3-year-old children. Pediatrics 119, e616–e623 (2007).
KM Barlow, E Thomson, D Johnson, RA Minns, Late neurologic and cognitive sequelae of inflicted traumatic brain injury in infancy. Pediatrics 116, e174–e185 (2005).
CDM van Karnebeek, MCE Jansweijer, AGE Leenders, M Offringa, RCM Hennekam, Diagnostic investigations in individuals with mental retardation: A systematic literature review of their usefulness. Eur J Hum Genet 13, 6–25 (2005).
CDM van Karnebeek, et al., Etiology of mental retardation in children referred to a tertiary care center: A prospective study. Am J Ment Retard 110, 253–267 (2005).
S Root, D Viskochil, C Leonard, J Carey, Genetic evaluation of children with developmental delay. Proceedings of the Greenwood Genetics Center 15, 159–160 (1996).
A Battaglia, E Bianchini, JC Carey, Diagnostic yield of the comprehensive assessment of developmental delay/mental retardation in an institute of child neuropsychiatry. Am J Med Genet 82, 60–66 (1999).
B Winnepenninckx, L Rooms, RF Kooy, Mental retardation: A review of the genetic causes. Br J Dev Disabil 49, 29–44 (2003).
DK Runyan, The challenges of assessing the incidence of inflicted traumatic brain injury: A world perspective. Am J Prev Med 34, S112–S115 (2008).

Information & Authors


Published in

Go to Proceedings of the National Academy of Sciences
Go to Proceedings of the National Academy of Sciences
Proceedings of the National Academy of Sciences
Vol. 109 | No. supplement_2
October 16, 2012
PubMed: 23045677


Submission history

Published online: October 8, 2012
Published in issue: October 16, 2012


  1. infant development
  2. colic
  3. excessive crying
  4. child maltreatment
  5. parenting


This work was supported by funds from the Canada Research Chair in Community Child Health Research and the Child and Family Research Institute (to R.G.B.).


This paper results from the Arthur M. Sackler Colloquium of the National Academy of Sciences, “Biological Embedding of Early Social Adversity: From Fruit Flies to Kindergartners,” held December 9–10, 2011, at the Arnold and Mabel Beckman Center of the National Academies of Sciences and Engineering in Irvine, CA. The complete program and audio files of most presentations are available on the NAS Web site at
This article is a PNAS Direct Submission.



Ronald G. Barr1 [email protected]
Developmental Neurosciences and Child Health, Child and Family Research Institute, British Columbia Children’s Hospital; and Department of Pediatrics, University of British Columbia Faculty of Medicine, Vancouver, BC, Canada V6H 3V4


Author contributions: R.G.B. wrote the paper.

Competing Interests

Conflict of interest statement: With regard to references to the Period of PURPLE Crying prevention program of the National Center on Shaken Baby Syndrome (NCSBS), the author declares the following: M. Barr is the Executive Director of the NCSBS, a 501(c)3 nonprofit organization. She receives no support other than her salary as Executive Director of the NCSBS. R.G.B. is a member of the International Advisory Board of the NCSBS. He receives no compensation for this role other than travel and lodging expenses for meetings. R.G.B. and M. Barr are married. The NCSBS and R.G.B. jointly hold the registered trademark for the Period of PURPLE Crying (Registration no. 2,962,262). R.G.B. received no financial benefit from Period of PURPLE Crying products sold by the NCSBS through the end of June 2007. In December 2007, the Governing Board of the NCSBS offered a royalty agreement to R.G.B. for a minor share of net profits from the future sale of Period of PURPLE Crying products in recognition of the intellectual property contribution by R.G.B. M. Barr was not involved in the creation of the agreement and was intentionally excluded and uninvolved in terms of the discussions, preparations, and review of the agreement to avoid any perception of a conflict of interest. The agreement was signed on December 22, 2007.

Metrics & Citations


Note: The article usage is presented with a three- to four-day delay and will update daily once available. Due to ths delay, usage data will not appear immediately following publication. Citation information is sourced from Crossref Cited-by service.

Citation statements



If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.

Cited by


    View Options

    View options

    PDF format

    Download this article as a PDF file


    Get Access

    Login options

    Check if you have access through your login credentials or your institution to get full access on this article.

    Personal login Institutional Login

    Recommend to a librarian

    Recommend PNAS to a Librarian

    Purchase options

    Purchase this article to get full access to it.

    Single Article Purchase

    Preventing abusive head trauma resulting from a failure of normal interaction between infants and their caregivers
    Proceedings of the National Academy of Sciences
    • Vol. 109
    • No. supplement_2
    • pp. 17143-17307







    Share article link

    Share on social media