Cognitive outcomes of children who have experienced complex trauma: a systematic review protocol.

OBJECTIVE: The objective of this systematic review is to assess cognitive outcomes of children who have experienced complex trauma in comparison to children who have not, and to test the effect of potential moderating factors.

INTRODUCTION: A relatively high proportion of children have experienced complex trauma, which can lead to negative consequences on various aspects of development, including cognitive functions. Studies and reviews have documented cognitive outcomes of children who have experienced complex trauma, but with conflicting results. Additionally, previous reviews only included few longitudinal studies. Thus, the short- and long-term effects of complex trauma on cognitive functions and the causal relationships between complex trauma and cognitive functions remain unclear; however, this information could help in the targeting of interventions.

INCLUSION CRITERIA: This review will consider primary prospective longitudinal studies that have assessed cognitive functions in children who have experienced complex trauma compared to children not exposed to a traumatic event.

METHODS: The following databases will be searched for primary studies: APA PsycNET, PubMed Central, ERIC, CINAHL and Embase. Gray literature will also be searched. Study selection, assessment of methodological quality and data extraction will be conducted by two independent evaluators. Standard meta-analysis as well as a longitudinal meta-analysis will be performed, based on the general linear mixed model, to take into account previous cognitive functioning. Subgroup analysis and meta-regression analysis will be undertaken to explore potential sources of heterogeneity, and a funnel plot will be generated to visually explore reporting bias. The quality of evidence will be assessed using the GRADE approach.

SYSTEMATIC REVIEW REGISTRATION NUMBER:: PROSPERO CRD42019121610.