Saliva samples for cortisol determination were also collected at each time point using a cotton Salivette (Sarstedt AG & Company, Nümbrecht, Germany). Samples were stored in a −80°C freezer and assayed using a high-sensitivity enzyme immunoassay kit that was standardized and validated at The University of Chicago Clinical Research Center Core Laboratory. The inter- and intra-assay coefficients of variation were 6.88% and 7.12%, respectively. Other measures (eg, psychomotor performance and eye movements) were also obtained in the sessions, and these data are reported elsewhere.67,71–74
