Using generalizability theory and the ERP reliability analysis (ERA) toolbox for assessing test-retest reliability of ERP scores part 2: Application to food-based tasks and stimuli.

If an ERP score is to reflect a trait-like characteristic or indicate if an intervention had an effect over time, adequate internal consistency and test-retest reliability of that ERP score across multiple testing sessions must be established. The current paper is a companion paper to Clayson et al. (current issue) that applied generalizability theory formulas and the ERP Reliability Analysis (ERA) Toolbox to assess test-retest and internal consistency in a dataset of event-related brain potentials (ERPs) assessing food-related cognition. Although ERPs in response to food cues have been related to eating behaviors or assessed during a health intervention, the reliability of food-related ERPs generally has not been tested. Within the generalizability theory framework, we assessed the stability (cf., test-retest reliability) and equivalence (cf., internal consistency) of four commonly used food-related ERPs: the late positive potential (LPP), centro-parietal P3, N2, and fronto-central P3. 132 participants (92 female) completed two testing sessions held two weeks apart. During the sessions, participants completed a passive food viewing task, a high-calorie go/no-go task, and a low-calorie go/no-go task in a counterbalanced fashion. Coefficients of equivalence for all ERPs were excellent (>0.96). Coefficients of stability were moderate-to-low, with N2 scores on the low-calorie go/no-go task showing the highest test-retest reliability (>0.65) and fronto-central P3 scores on the high-calorie go/no-go task showing the lowest (0.48). Results suggest the ERPs in the current dataset have high internal consistency and would be reliable in detecting individual differences, but their test-retest reliability is limited. Reliability of these ERPs may be improved with changes in task stimuli, task instructions, and study procedures.