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Much effort has been devoted to incorporating haptic feedback into surgical simulators. However, the benefits of haptics for novice trainees in the early stages of learning are not clear. Presumably, novices have less spare attentional resources to attend to haptic cues while learning basic laparoscopic skills. The aim of this study was to determine whether novice surgeons have adequate cognitive resources to attend to haptic information. Thirty surgical residents and attendings performed a TransferPlace task in a simulator, with and without haptics. Cognitive loading was imposed using a mental arithmetic task. Subjects performed 10 trials (five with cognitive loading and five without) with and without haptics. Results showed that all subjects performed significantly slower (27%) when they were cognitively loaded than unloaded, but equally accurately in both cases, suggesting a speed-accuracy tradeoff. On average, subjects performed 36% faster and 97% more accurately with haptics than without, even while cognitively loaded. Haptic feedback can not only enhance performance, but also counter the effect of cognitive load. This effect is greater for more experienced surgeons than less experienced ones, indicating greater spare cognitive capacity in surgeons with more experience.

Background The benefits of haptic feedback in laparoscopic surgery training simulators is a topic of debate in the literature. It is hypothesized that novice surgeons may not benefit from the haptic information, especially during the initial phase of learning a new task. Therefore, providing haptic feedback to novice trainees in the early stage of training may be distracting and detrimental to learning. Objective A controlled experiment was conducted to examine the effect of haptic feedback on the learning curve of a complex laparoscopic suturing and knot-tying task. Method The ProMIS and the MIST-VR surgical simulators were used to represent conditions with and without haptic feedback, respectively. Twenty novice subjects (10 per simulator) were trained to perform suturing and knot-tying and practiced the tasks over eighteen one-hour sessions. Results At the end of the 3-week training period, subjects performed equally fast but more consistently with haptics (ProMIS) than without (MIST-VR). Subjects showed slightly higher learning rate and reached the first plateau of the learning curve earlier with haptic feedback. Conclusion In general, learning with haptic feedback was significantly better than without haptic feedback for a laparoscopic suturing and knot-tying task, but only in the first 5 hours of training. Application Haptic feedback may not be warranted in laparoscopic surgical trainers. The benefits of a shorter time to the first performance plateau and more consistent initial performance should be balanced with the cost of implementing haptic feedback in surgical simulators.

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Based on the polarization analysis of teleseismic SKS waveform data recorded at 30 seismic stations of the regional digital seismograph networks in the northeastern margin of the Tibetan Plateau, the SKS fast-wave direction and the delay time between the fast and slow shear waves at each station were determined by use of the grid searching method of minimum tangent energy and the stacking analysis method, and then we acquired the image of upper mantle anisotropy in the northeastern margin of the Tibetan Plateau. In the study region, the fast-wave polarization direction is basically in NW-SE direction and shows a clockwise rotation trend, and the delay time falls into the interval from 0.70 to 1.51 s. The fast-wave polarization direction is consistent with the strike of the major faults in the region. The variation of the fast-wave directions is similar to the variation of the minimum average principal compressional stress directions in the northeast margin of the Tibetan Plateau, and to the variation of GPS velocity directions. The research results imply that the regional tectonic stress field has resulted in deformation and flow of upper mantle material as a clockwise rotation, and made the alignment of upper mantle peridotite lattice parallel to the direction of material deformation. The deformation of the crust and upper mantle is possibly vertically coherent.