Surgical residents are exposed to a significant amount of cognitive load during call. While various efforts have been made to quantify the effect of fatigue and sleep deprivation on the psychomotor skills of surgical residents, there is very little investigations into the effect of these factors on cognitive skills. However, this is an important issue in medical curriculum design, as much of the medical errors are procedural in nature and are not psychomotor. In this paper, we present a study that aimed to quantify the effect of fatigue on cognitive skills. We employed hand movement data for developing a proficiency measure of surgical skill. The difference in proficiencies measured through hand movement post call and pre call was determined. The simulation tasks were designed to challenge working memory, attention of the user. The results showed a significant difference in hand movement proficiencies as well as behavioral errors pre and post-call. EEG Data was also gathered during simulation tasks pre and post call through the B-Alert® Bluetooth EEG technology. The B-Alert® software was analyzed to reveal ratings of alertness/drowsiness, engagement, mental workload and distraction. The results showed statistically significant difference in EEG ratings in pre call and post call condition.