Shirk, Steven D.McLaren, Donald G.Bloomfield, Jessica S.Powers, AlexDuffy, AlecMitchell, Meghan B.Ezzati, AliAlly, Brandon A.Atri, Alireza2017-07-242017Shirk, Steven D., Donald G. McLaren, Jessica S. Bloomfield, Alex Powers, Alec Duffy, Meghan B. Mitchell, Ali Ezzati, Brandon A. Ally, and Alireza Atri. 2017. “Inter-Rater Reliability of Preprocessing EEG Data: Impact of Subjective Artifact Removal on Associative Memory Task ERP Results.” Frontiers in Neuroscience 11 (1): 322. doi:10.3389/fnins.2017.00322. http://dx.doi.org/10.3389/fnins.2017.00322.http://nrs.harvard.edu/urn-3:HUL.InstRepos:33490758The processing of EEG data routinely involves subjective removal of artifacts during a preprocessing stage. Preprocessing inter-rater reliability (IRR) and how differences in preprocessing may affect outcomes of primary event-related potential (ERP) analyses has not been previously assessed. Three raters independently preprocessed EEG data of 16 cognitively healthy adult participants (ages 18–39 years) who performed a memory task. Using intraclass correlations (ICCs), IRR was assessed for Early-frontal, Late-frontal, and Parietal Old/new memory effects contrasts across eight regions of interest (ROIs). IRR was good to excellent for all ROIs; 22 of 26 ICCs were above 0.80. Raters were highly consistent in preprocessing across ROIs, although the frontal pole ROI (ICC range 0.60–0.90) showed less consistency. Old/new parietal effects had highest ICCs with the lowest variability. Rater preprocessing differences did not alter primary ERP results. IRR for EEG preprocessing was good to excellent, and subjective rater-removal of EEG artifacts did not alter primary memory-task ERP results. Findings provide preliminary support for robustness of cognitive/memory task-related ERP results against significant inter-rater preprocessing variability and suggest reliability of EEG to assess cognitive-neurophysiological processes multiple preprocessors are involved.en-USEEG/ERPmemorypreprocessinginter-rater reliabilityartifactsJournal Article2017-07-2410.3389/fnins.2017.00322