Qu’en est-il des tout-petits? : conséquences d’un traumatisme crânio-cérébral durant la petite enfance

Pediatric Traumatic Brain Injury (TBI) constitutes one of the most enigmatic insults, as it affects a complex organ and occurs at a sensitive period in the developmental course. Despite epidemiological data indicating a particularly high incidence of TBI during early childhood and growing concerns regarding its potential impact on child functioning and well-being, early TBI remains a poorly studied public health problem, especially compared to TBI sustained by schooledaged children and in sports settings. Also, all too often, the objectives, hypotheses, constructs and theories studied in young children with TBI are extrapolated from those used in older individuals and therefore rarely chosen in consideration of the developmental concerns specific to early childhood. These issues limit a comprehensive and refined understanding of the consequences of early TBI. So, what about the little ones? The general objective of the thesis was to review the current state of the empirical literature pertaining to children who have sustained TBI during early childhood, and to study the impact of early TBI on a key domain of this developmental period, namely temperament. The first article presented in the thesis is a systematic review of the literature aiming to identify and synthetize the findings concerning cognitive and behavioral consequences following early TBI. Four databases were searched from 1990 to 2019 using key terms related to TBI and early childhood. Of 12,153 articles identified during the initial search, 43 were included. This review of the literature highlights that children who sustain early TBI display a range of difficulties which are generally more pronounced and detrimental when injury is more severe, sustained at a young age, and the cause is non-accidental. The second article constitutes an empirical study aiming to explore temperament after early TBI. Temperament refers to young children’s behavioral tendencies, that is, their way of reacting and adapting to their environment. Besides constituting an important predictor of outcome in several areas of functioning, this construct also takes into account the developmental reality of the young child and could thus be particularly suited to investigate and clarify the consequences of early childhood TBI. Parents of 173 young children (age: 36 ± 12 months) with simple mTBI (n = 83), more severe TBI (mild complicated, moderate or severe, n = 21) or orthopedic injury (n = 69) completed a questionnaire reflecting their child's temperament profile before the injury as well as at 6 and 18 months following the injury. The results reveal that children who sustain more severe TBI experience a slower evolution of the developmental trajectory of the Surgency dimension of temperament. In other words, these children exhibit a reduced activity level which is reflected by less energy, a reduced desire for high-intensity pleasure-seeking, as well as greater shyness in the face of novelty. In general, the thesis highlights that the occurrence of TBI during early childhood, a sensitive period for the emergence of basic cognitive and social skills and a time when environmental influences are particularly salient, can cause a large range of consequences, even affecting the trajectory of temperament. Given the high prevalence of TBI in early childhood and the potential for adverse outcomes, it is essential that research, clinical management, intervention and prevention efforts be further developed based on the empirical literature, and in a manner that takes into account the unique characteristics of early childhood.

Keyphrases: TCC accidentel, TCC non-accidentel, Cognition, Parent, Accidental TBI, Non-accidental TBI, Early childhood, Systematic review, Behavior, Environment