[Formula: see text] Interventions to improve executive functions in children and adolescents with acquired brain injury: a systematic review and multilevel meta-analysis.

To investigate the effectiveness of interventions aiming to improve hot and cold executive functions (EFs) in children and adolescents with acquired brain injury (ABI) and to examine whether characteristics of the intervention, participants, etiology of ABI (Traumatic-brain-injury [TBI] or non-TBI), time of assessment, or study quality moderate intervention effects. Whereas cold EFs refer to purely cognitive EFs, hot EFs refer to the affective aspects of these cognitive skills. A total of 970 participants from 23 randomized-controlled-trial studies (112 effect sizes [ES]) were included. A three-level random effects approach (studies, ES, individual participants) was used. Moderation analyses were conducted through meta-regressions. The three-level random effects model showed a better fit than the two-level model. Almost all individual studies showed non-significant ES across outcomes but in combination interventions were effective (Cohen's d = 0.38, CI 0.16 ~ 0.61). Lower methodological quality, inclusion of participants with non-TBI, and parental participation predicted larger ES. Participants' age, time of assessment, number of sessions, and focus on hot or cold EFs were not related to ES. We found no evidence of publication bias. Interventions are effective with small to medium ES according to conventional criteria. Intervention effects do not seem to fade away with time. Parent participation in the intervention is important to improve EFs. The efficacy of interventions seems larger when non-TBI is part of the etiology of ABI. Variation between studies is relevant for tracing the effective intervention characteristics. Most studies are conducted in adolescence, and studies in early childhood are needed.