The current study provided psychometric information on the parent and child version of the Behavioural Inhibition System (BIS)/Behavioural Approach System (BAS) scale. Parent-child agreement was evaluated (N = 217, 7.5 to 14 years, 50% boys). Moreover, absolute and rank order stability of mother-reported BIS/BAS scores over a 2-year period were assessed (N = 207, 5.5 to 11 years at baseline, 49% boys). Only full measurement invariant (sub-)scales were considered in the parent-child agreement and longitudinal stability assessment. Parent and child ratings were found to be measurement invariant but discrepant on BAS Drive and BAS Reward Responsiveness. In younger children, child ratings on BAS Drive tended to be higher than parent ratings, whereas in older children, child ratings tended to be lower than parent ratings. Further, the discrepancy between the BAS Drive ratings of fathers and children was higher than the discrepancy between the BAS Drive ratings of mothers and children. Finally, the study results suggested 2-year absolute and rank order stability of the measurement-invariant, mother-reported BIS and BAS Drive scores in children aged 5.5 to 11 years at baseline.

The dimensions of postconcussive symptoms (PCS) were examined in a prospective, longitudinal study of 186 8 to 15 year old children with mild traumatic brain injuries (TBI). Parents and children completed a 50-item questionnaire within 2 weeks of injury and again at 3 months after injury, rating the frequency of PCS on a 4-point scale. Common factor analysis with target rotation was used to rotate the ratings to four hypothesized dimensions, representing cognitive, somatic, emotional, and behavioral symptoms. The rotated factor matrix for baseline parent ratings was consistent with the target matrix. The rotated matrix for baseline child ratings was consistent with the target matrix for cognitive and somatic symptoms but not for emotional and behavioral symptoms. The rotated matrices for ratings obtained 3 months after injury were largely consistent with the target matrix derived from analyses of baseline ratings, except that parent ratings of behavioral symptoms did not cluster as before. Parent and child ratings of PCS following mild TBI yield consistent factors reflecting cognitive and somatic symptom dimensions, but dimensions of emotional and behavioral symptoms are less robust across time and raters. (JINS, 2009, 15, 19–30.)