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

  • Di Zhang
  • Salvatore Sessa
  • Weisheng Kong
  • Sarah Cosentino
  • Daniele Magistro
  • Hiroyuki Ishii
  • Massimiliano Zecca
  • Atsuo Takanishi
Original Article



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.


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.


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.


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.


Laparoscopy Subliminal persuasion Workload Subliminal visual stimuli Supraliminal visual stimuli 



This study was partially supported by the research institute of science and engineering, Waseda University. This research has been supported by the JSPS Scientific Research-C Grant [24500616], the JSPS Grant-in-Aid for Young Scientists (Wakate B) [25750259], the Waseda University Grant for Special Research Projects (for new full-time 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, which also provided the core sensors and the microcontroller. The authors would like to express their thanks to the Italian Ministry of Foreign Affairs, General Directorate for Cultural Promotion and Cooperation, for its support to RoboCasa. The authors would also like to express their gratitude to Life Performance Research for their support to the research.

Conflict of interest

The authors declare no conflicts of interest in preparing this article.


  1. 1.
    Johnson A (1997) Laparoscopic surgery. Lancet 349:631–635CrossRefPubMedGoogle Scholar
  2. 2.
    Novitsky YW, Litwin DEM, Callery MP (2004) The net immunologic advantage of laparoscopic surgery. Surg Endosc 18:1411–1419CrossRefPubMedGoogle Scholar
  3. 3.
    Kennedy GD, Heise C, Rajamanickam V, Harms B, Foley EF (2009) Laparoscopy decreases postoperative complication rates after abdominal colectomy. Ann Surg 249:596–601CrossRefPubMedGoogle Scholar
  4. 4.
    Golub R, Siddiqui F, Pohl D (1998) Laparoscopic Versus Open Appendectomy: A Metaanalysis. J Am Coll Surg 186:545–553CrossRefPubMedGoogle Scholar
  5. 5.
    Lacy AM, García-Valdecasas JC, Delgado S, Castells A, Taurá P, Piqué JM, Visa J (2002) Laparoscopy-assisted colectomy versus open colectomy for treatment of non-metastatic colon cancer: a randomised trial. Lancet 359:2224–2229CrossRefPubMedGoogle Scholar
  6. 6.
    Perrin M, Fletcher A (2004) Laparoscopic abdominal surgery. Contin Educ Anaesth Crit Care Pain 4:107–110CrossRefGoogle Scholar
  7. 7.
    Berguer R, Smith WD, Chung YH (2001) Performing laparoscopic surgery is significantly more stressful for the surgeon than open surgery. Surg Endosc 15:1204–1207CrossRefPubMedGoogle Scholar
  8. 8.
    Berguer R, Remler M, Beckley D (1997) Laparoscopic instruments cause increased forearm fatigue: a subjective and objective comparison of open and laparoscopic techniques. Minim Invasive Ther Allied Technol 6:36–40CrossRefGoogle Scholar
  9. 9.
    Tanoue K, Ieiri S, Konishi K, Yasunaga T, Okazaki K, Yamaguchi S, Yoshida D, Kakeji Y, Hashizume M (2008) Effectiveness of endoscopic surgery training for medical students using a virtual reality simulator versus a box trainer: a randomized controlled trial. Surg Endosc 22:985–990CrossRefPubMedGoogle Scholar
  10. 10.
    Lin Z, Uemura M, Zecca M, Sessa S, Ishii H, Bartolomeo L, Itoh K, Tomikawa M, Hashizume M, Takanishi A (2011) Waseda Bioinstrumentation system WB-3 as a wearable tool for objective laparoscopic skill evaluation. In: IEEE international conference on robotics and automation (ICRA), pp 5737–5742Google Scholar
  11. 11.
    Corlett EN, Bishop RP (1976) A technique for assessing postural discomfort. Ergonomics 19:175–182CrossRefPubMedGoogle Scholar
  12. 12.
    Bhatnager V, Drury CG, Schiro SG (1985) Posture, postural discomfort, and performance. Hum Factors 27:189–199PubMedGoogle Scholar
  13. 13.
    Kanfer R, Ackerman P (1989) Motivation and cognitive abilities: an integrative aptitude-treatment interaction approach to skill acquisition. J Appl Psychol 74:657–690CrossRefGoogle Scholar
  14. 14.
    Lysaught RJ, Hill SG, Dick AO, Plamondon BD, Linton PM, Wierwille WW, Zaklad AL, Bittner AC, Wherry RJ (1989) Operator workload: comprehensive review and evaluation of operator workload methodologies. Report No. 851. Analytics, Willow GroveGoogle Scholar
  15. 15.
    Cohen MA, Cavanagh P, Chun Marvin M, Nakayama K (2012) The attentional requirements of consciousness. Trends Cogn Sci 16:411–417CrossRefPubMedGoogle Scholar
  16. 16.
    Egermann H, Kopiez R, Reuter C (2006) Is there an effect of subliminal messages in music on choice behavior? J Artic Support Null Hypothesis 4(2):29–46Google Scholar
  17. 17.
    Rosen DL, Singh SN (1992) An investigation of subliminal embed effect on multiple measures of advertising effectiveness. Psychol Mark 9(2):157–173CrossRefGoogle Scholar
  18. 18.
    Riener A (2012) Subliminal persuasion and its potential for driver behavior adaptation. Trans Intell Transp Syst 13(1):71–80CrossRefGoogle Scholar
  19. 19.
    Lin Z, Zecca M, Sessa S, Bartolomeo L, Ishii H, Takanishi A (2011) Development of the wireless ultra-miniaturized inertial measurement unit WB-4: preliminary performance evaluation. In: Annual international conference of the IEEE Engineering in Medicine and Biology Society, EMBC, pp 6927–6930Google Scholar
  20. 20.
    Lin Z, Zecca M, Sessa S, Bartolomeo L, Ishii H, Itoh K, Takanishi A (2010) Development of the miniaturized wireless Inertial Measurement Unit WB-4: Pilot test for mastication analysis. In: 2010 IEEE/SICE International Symposium on System Integration (SII). IEEE, pp 420–425Google Scholar
  21. 21.
    Kantowitz BH (1988) Defining and measuring pilot mental workload. In: Comstock JR Jr (ed) Mental state estimation 1987. National Aeronautics and Space Administration, Scientific and Technical Information Division, Hampton, pp 179–188Google Scholar
  22. 22.
    Strayer DL, Cooper JM, Turrill J, Coleman J, Medeiros-Ward N, Biondi F (2013) Measuring cognitive distraction in the automobile. Monograph of AAA Foundation for Traffic Safety, Washington DC, USGoogle Scholar
  23. 23.
    Derossis AM, Fried GM, Abrahamowicz M, Sigman HH, Barkun JS, Meakins JL (1998) Development of a model for training and evaluation of laparoscopic skills 1. Am J Surg 175:482–487CrossRefPubMedGoogle Scholar
  24. 24.
    Ritter EM, Scott DJ (2007) Design of a proficiency-based skills training curriculum for the fundamentals of laparoscopic surgery. Surg Innov 14:107–112CrossRefPubMedGoogle Scholar

Copyright information

© CARS 2015

Authors and Affiliations

  • Di Zhang
    • 1
  • Salvatore Sessa
    • 1
  • Weisheng Kong
    • 1
  • Sarah Cosentino
    • 1
  • Daniele Magistro
    • 2
  • Hiroyuki Ishii
    • 1
  • Massimiliano Zecca
    • 3
    • 4
    • 5
  • Atsuo Takanishi
    • 6
    • 7
  1. 1.Faculty of Science and EngineeringWaseda UniversityTokyoJapan
  2. 2.Department of PsychologyTorino UniversityTorinoItaly
  3. 3.Loughborough UniversityLoughboroughUK
  4. 4.National Centre for Sports and Exercise Medicine – East Midlands (NCSEM-EM)LoughboroughUK
  5. 5.NIHR Leicester-Loughborough DietLifestyle and Physical Activity Biomedical Research Unit (BRU)LoughboroughUK
  6. 6.Department of Modern Mechanical EngineeringWaseda UniversityTokyoJapan
  7. 7.Humanoid Robotics InstituteWaseda UniversityTokyoJapan

Personalised recommendations