Internal Consistency of Functional Magnetic Resonance Imaging and Electroencephalography Measures of Reward in Late Childhood and Early Adolescence

BACKGROUND: Abnormal neural response to reward is increasingly thought to function as a biological correlate of emerging psychopathology during adolescence. However, this view assumes that such responses have good psychometric properties, especially internal consistency-an assumption that is rarely tested. METHODS: Internal consistency (i.e., split-half reliability) was calculated for event-related potential (ERP) and blood oxygen level-dependent (BOLD) responses to monetary gain and loss feedback from the same sample of 8- to 14-year-old girls (N = 177). Internal consistency for ERP (i.e., feedback negativity) and BOLD responses within the ventral striatum and medial and/or lateral prefrontal cortex to gain, loss, difference scores (gain - loss), and residual scores (gain controlling for loss) was compared. Moderation analyses were conducted to investigate whether internal consistency differed by age. RESULTS: ERP and BOLD responses to gain and loss feedback showed high internal consistency in all regions (Spearman-Brown coefficients >= .70). When considering difference and residual scores, however, responses showed lower internal consistency (Spearman-Brown coefficients <= .50), with particularly low internal consistency for subtraction-based scores (Spearman-Brown coefficients <= .36). Age was not a significant moderator of split-half relationships, indicating similar internal consistency across late childhood to early adolescence. CONCLUSIONS: Within the same subjects, high internal consistency was observed for both ERP and BOLD responses to gains and losses, which did not vary as a function of age. Moreover, excellent psychometric properties were evident even within the first half of the experiment. Difference scores were characterized by lower internal consistency, although regression-based approaches outperformed subtraction-based difference scores.