Background: Innovators claim that haptic feedback will make better simulators. However, research suggests that haptics is less useful for novice surgeons than experts on a surgical simulator. The aim of our study was to determine whether the difference in available cognitive resources to attend to haptic information affects surgical task performance.
Method: 22 surgical residents and surgeons (5 PGY1s, 4 PGY2s, 5 PGY3s, 3PGY4s, 1 PGY5 and 4 attending/fellows) performed TransferPlace tasks on the ProMIS and MIST-VR simulators. The experimental design was a 2 (haptics) x 2 (cognitive loading) x 6 (experience) mixed design. Haptics was available on the ProMIS but not on the MIST simulator. Cognitive loading was imposed using a mental arithmetic task. Subjects performed 10 trials (5 with cognitive loading and 5 without) on each simulator. The order of cognitive loading was randomized, while the order of haptics (simulator) was counterbalanced. Time to task completion and errors were measured and analysed in a 3-way ANOVA and paired t-tests.
Results: In general, expert surgeons performed faster (p<0.01) but not more accurately than novice surgeons. With cognitive loading, subjects performed 31% more slowly (p<0.01), but equally accurately, as without cognitive loading, suggesting a speed-accuracy tradeoff. When haptic feedback was provided, subjects performed 36% (p<0.01) faster and 95% more accurately. Interestingly, subjects performed 16% faster and 97% more accurately with haptics than without, even while cognitively loaded, suggesting that haptics not only counters the effect of cognitive loading, but also enhances performance. These effects are more pronounced for experts.
Conclusion: Surgeons can think and operate at the same time, but much more slowly and with more errors. Haptic feedback can enhance performance. This enhancement is greater for expert surgeons than novices, indicating more spare cognitive capacity in experts.