Prevalence and predictors of affective lability after paediatric traumatic brain injury.

OBJECTIVE: Paediatric severe traumatic brain injury (TBI) is associated with significant post-injury affective and behavioural problems. Few studies have examined the prevalence and characteristics of affective lability after paediatric TBI. METHODS: Ninety-seven children with severe TBI were evaluated 1 year post-injury for the presence of affective lability using the Children's Affective Lability Scale (CALS). Demographic, clinical and brain lesion characteristics were also assessed. RESULTS: Affective lability significantly increased after injury. Eighty-six children had a pre-injury CALS score of 1 SD or less from the group pre-injury mean (M = 8.11, SD = 9.31), of which 35 and 15 children had a 1 SD and 2 SD increase in their CALS score from pre- to post-injury, respectively. A variety of affective shifts manifested post-injury including anxiety, silliness, dysphoria and irritability. The most severe symptoms were irritability and unpredictable temper outbursts. Risk factors for affective lability included elevated pre-injury affective lability and psychosocial adversity as well as greater damage to the orbitofrontal cortex. Post-injury affective lability was most frequently associated with a post-injury diagnosis of attention-deficit hyperactivity disorder. CONCLUSIONS: Affective lability is common after paediatric TBI and frequently manifests as irritability and unpredictable outbursts. Early intervention is needed to improve psychiatric outcomes.

Enhanced right amygdala activity in adolescents during encoding of positively valenced pictures.

While studies among adults implicate the amygdala and interconnecting brain regions in encoding emotional stimuli, few studies have examined whether developmental changes occur within this emotional-memory network during adolescence. The present study examined whether adolescents and adults differentially engaged the amygdala and hippocampus during successful encoding of emotional pictures, with either positive or negative valence. Eighteen adults and twelve adolescents underwent event-related fMRI while encoding emotional pictures. Approximately 30 min later, outside the scanner, subjects were asked to recall the pictures seen during the scan. Age group differences in brain activity in the amygdala and hippocampus during encoding of the pictures that were later successfully and unsuccessfully recalled were separately compared for the positive and negative pictures. Adolescents, relative to adults, demonstrated enhanced activity in the right amygdala during encoding of positive pictures that were later recalled compared to not recalled. There were no age group differences in amygdala or hippocampal activity during successful encoding of negative pictures. The findings of preferential activity within the adolescent right amygdala during successful encoding of positive pictures may have implications for the increased reward and novelty seeking behavior, as well as elevated rates of psychopathology, observed during this distinct developmental period.