Brain Resource International Database Reproducibility of Psychometric and Psychophysiology data  (Sydney sample) Summary Across both EEG and ERP measures, there no significant changes from session 1 to session 2, when key covariates (age, gender) were controlled. Similarly, psychometric measures were also stable across the 4 week repeat period, when these key covariates were controlled. Subjects Subjects:  A total of 21 healthy volunteers (11 males, 10 females, mean age in years = 27.76, sd = 13.47, range = 12-57; mean years of education = 15.14, sd = 2.29, range = 9-18), who returned for repeat recordings after 4 weeks. A wide age range was used to address concerns in previous psychophysiology reproducibility studies (restricted to limited age ranges, without older/younger subjects). Table1 presents the demographic data for the sample. The subjects were screened using the standard BRID criteria. Procedure: All subjects completed both psychometric and psychophysiology testing for Session 1 and Session 2. Data acquisition and analysis protocols, and results are reported separately for each testing component. Psychophysiology Acquisition and Analysis EEG and ERP data were acquired using the standard BRID protocols. EEG: Both resting eyes closed and eyes open conditions, with parameters of the power spectrum estimated for delta (1.5-3.5Hz) theta (4-7.5Hz), alpha (8-13Hz) and beta (14.5-30Hz) frequency bands. ERP:  We included ERPs to the auditory oddball and working memory tasks. Auditory Oddball: target ERPs N100 (80-140ms), P200 (140-270ms), N200 (180-320ms), P300 (270-550ms) – and background ERPs N100, P200. Working memory: background ERPs  P150 (115-190ms) and P300 (285-600ms). Within-subjects multiple analyses of covariance were conducted with session x condition (eg. eyes closed/open) x midline, with age and sex as covariates (given robust evidence for relationships between age, sex and psychophysiological function). Psychophysiology Results EEG Power:  There were no significant differences involving Session for EEG power, when age and sex were controlled for [1] . EEG Frequency: There were no significant effects involving Session. ERP (Oddball): Again, there were no significant effects involving Session when age and sex were controlled [2] . ERP (Working memory): There were also no significant effects involving Session for P150 and P300 data. Psychological Data: Procedure and acquisition The tests included: Choice Reaction-time Spot the real word test Span of visual memory test Digit span Switching of Attention (parts 1 and 2) Word Interference Test (Stroop) Word Generation (FAS) These tests generate 16 scores, such that the stringent corrected alpha level is .05/16 = .003. Given that scores from the same test might be considered repeated measures, we used an alpha level of .05/7 = .007. Psychological test Results The results showed no significant changes across test-retest (Session) for any of the tests [3] . [1] When age and sex were not included as covariates, the following session effects were observed: Theta power: Session effect (F = 16.62, p = .001); Session by condition interaction of marginal significance (F = 4.72, p = .042). Alpha power: Session by midline interaction (F = 3.87, df = 2,19, p = .039). This pattern of results suggests that any significant effects involving session are due to the contribution of demographic (age, gender) factors rather than to practice effects per se. [2] When age and gender were not controlled for, N100 latency for backgrounds was slightly longer in session 2 (by about 5ms, F = 4.92, df = 1,18, p = .04). For targets, both N200 latency (F= 4.90, df = 1,18, p = .042) and P300 latency (F= 4.84, df = 1,17, p = .042) were slightly longer for Session 2. Together, these data suggest a slight latency shift of the whole waveform in Session 2 – a shift that interacts with demographic data. [3] Only when age/gender were not controlled was the following Session main effect observed at the corrected alpha level: Switching of Attention, Part 2) (F = 9.47, df = 20, p = .006. At the uncorrected alpha level, the following Session effects were observed:  Spot the Real Word (F = 7.18, p = .014);  Word Generation, FAS (F = 5.69, p = .027); Memory Recall Total (F = 10.27, p = .004).

Feedback  -   Copyright  -   Disclaimer  -   Contact us  -   Participate   -   Acknowledgements   -   Sitemap