Cognitive Load Assessment of Simulated Laparoscopic Surgical Tasks Using Optical Imaging.

Faiz U Shariff, MD1, Mashaal Syed2, Elizabeth Renza-Stingone, MD1, Hasan Ayaz, PhD2, Andres Castellanos, MD1, D Scott Lind, MD1, Patricia A Shewokis, PhD1. 2School of Biomedical Engineering, Science & Health Systems, Drexel University, Philadelphia, PA, 19104, USA, 1Department of Surgery, College of Medicine, Drexel University, Philadelphia, PA 19102, USA

INTRODUCTION: We hypothesized that applying cognitive load theory (CLT) to simulation will enhance the retention and transfer of surgical skills. Functional near infrared spectroscopy (fNIR) is a novel, noninvasive neural optical imaging tool that indirectly measures cognitive workload by monitoring the hemodynamics of prefrontal cortex (PFC) activation. To optimize germane load, we applied the contextual interference principle (blocked (BL) and random (RA) practice orders).  Intrinsic load was managed by a variation on the simple-to-complex strategy, by comparing the simpler acquisition simulated laparoscopic skills to a more difficult transfer laparoscopic skill.  We assessed selected performance metrics and PFC brain activation regions during the retention and transfer of multiple, simulated laparoscopic skills.

METHODS: Eleven third year medical students acquired three skills on a laparoscopic simulator (Surgical Science®) and were randomly assigned to either a BL or RA practice orders.  Students performed 108 acquisition trials, across three days, of 3 simulated laparascopic skills.  A 72-hr retention interval followed skill acquisition, after which 6 retention trials of the acquired skills and 6 transfer trials (2 different simulated laparoscopic tasks) were performed (See Figure 1). Performance metrics (Global score, Total time and other selected measures) and hemodynamic responses (total hemoglobin) were assessed during skill retention and transfer in four different region of the PFC. Non-parametric randomization tests with 10,000 Monte Carlo samples were used to determine if there were differences between BL vs RA practice orders for each skill separately. The significance criterion for all tests was set at α= 0.05.

RESULTS: During retention and transfer, RA performed the surgical skills in significantly less time, had fewer error and had lower change in total Hemoglobin in the right dorsolateral PFC than the BL group (Table 1). 

CONCLUSIONS: We were able to objectively measure cognitive load using fNIR measures of the anterior and dorsolateral PFC hemodynamic response. Compared with BL practice, RA practice resulted in enhanced learning through better performance and less cognitive load for retention and transfer of simulated laparoscopic surgical skills. Application of CLT in this study helped designed an instructional paradigm that managed the intrinsic load and optimized the germane load that lead to enhance learning. 

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