Loughborough University
CARS 2015 - Di ZHANG - Subliminal (revision) .pdf (730.38 kB)

Development of subliminal persuasion system to improve the upper limb posture in laparoscopic training: a preliminary study

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journal contribution
posted on 2015-05-22, 15:21 authored by Di Zhang, Salvatore Sessa, Weisheng Kong, Sarah Cosentino, Daniele Magistro, Hiroyuki Ishii, Massimiliano Zecca, Atsuo Takanishi
Purpose: Current training for laparoscopy focuses only on the enhancement of manual skill and does not give advice on improving trainees’ posture. However, a poor posture can result in increased static muscle loading, faster fatigue, and impaired psychomotor task performance. In this paper, the authors propose a method, named subliminal persuasion, which gives the trainee real-time advice for correcting the upper limb posture during laparoscopic training like the expert but leads to a lower increment in the workload. Methods: A 9-axis inertial measurement unit was used to compute the upper limb posture, and a Detection Reaction Time device was developed and used to measure the workload. A monitor displayed not only images from laparoscope, but also a visual stimulus, a transparent red cross superimposed to the laparoscopic images, when the trainee had incorrect upper limb posture. One group was exposed, when their posture was not correct during training, to a short (about 33 ms) subliminal visual stimulus. The control group instead was exposed to longer (about 660 ms) supraliminal visual stimuli. Results: We found that subliminal visual stimulation is a valid method to improve trainees’ upper limb posture during laparoscopic training. Moreover, the additional workload required for subconscious processing of subliminal visual stimuli is less than the one required for supraliminal visual stimuli, which is processed instead at the conscious level. Conclusions: We propose subliminal persuasion as a method to give subconscious real-time stimuli to improve upper limb posture during laparoscopic training. Its effectiveness and efficiency were confirmed against supraliminal stimuli transmitted at the conscious level: Subliminal persuasion improved upper limb posture of trainees, with a smaller increase on the overall workload.


This study was partially supported by the research institute of science and engineering, Waseda University. This research has been supported by the JSPS ScientificResearch-C Grant [24500616], the JSPS Grant-in-Aid forYoung Scientists (Wakate B) [25750259], the Waseda University Grant for Special Research Projects (for new fulltime faculty) [2014S-091], the Global COE Program “Global Robot Academia”, MEXT, Japan, and the Consolidated Research Institute for Advanced Science and Medical Care,Waseda University (ASMeW). It was also partially supported by a Grant by STMicroelectronics.



  • Mechanical, Electrical and Manufacturing Engineering

Published in

International Journal of Computer Assisted Radiology and Surgery


ZHANG, D. ... et al, 2015. Development of subliminal persuasion system to improve the upper limb posture in laparoscopic training: a preliminary study. International Journal of Computer Assisted Radiology and Surgery, 10(11), pp.1863-1871.


© Springer Verlag


  • AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date



The final publication is available at Springer via http://dx.doi.org/10.1007/s11548-015-1198-x






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