Human Factors Guidelines for Interactive 3D and Games-Based ...

The ITT, therefore, was designed to deliver decision-based training with the aim of enhancing or
refreshing the knowledge of those defence surgeons being deployed on operations – many of
whom may not have had prior exposure to trauma incidents and procedures. In order to foster the
correct decision-making behaviours under the pressure of time, the ITT presents trainees with high
physical fidelity scenes of the hospital tent environment. At certain stages throughout the 5-minute
virtual life-saving procedure, multiple-choice
questions are displayed relating to procedures
such as blood testing and fluid administration.
Medical instruments are also displayed to a high
level of physical fidelity, as are the animations
depicting their application to, and effect on the
virtual casualty. However, to interact with these
high physical fidelity items, the end user only
has to undertake simple mouse movements and
mouse button clicks, indicating which item he or
she requires and where he or she wishes to
apply that item.
The term “hybrid” physical fidelity, as shown in
the middle of the continuum in Figure 19, refers
to instances where a task analysis highlights the
need for a simulator to possess higher physical
fidelity in one sensory attribute over another. In
such a case, it may become necessary to
develop, procure and/or modify special-purpose
32
Figure 21: Image taken of patient preparation
activities during field hospital observation
opportunity.
Source: Author’s Image Archive
interfaces in order to ensure the stimuli defined by the analysis as being essential in the
development of skills or knowledge are presented to the end user using appropriate technologies.
Take, for example, a medical (mastoidectomy 26 ) simulator developed as part of a European Unionfunded
project called IERAPSI 27 . Here, the task analysis undertaken whilst observing ear, nose
and throat (ENT) surgeons, together with actual “hands-on” experience using a cadaveric temporal
bone, drove the decision to adopt a hybrid physical fidelity solution based on:
(a) a simplified visual representation of the
temporal bone region (omitting any features
relating to the remaining skull areas or
middle/inner ear structures);
(b) a sophisticated software simulation
reproducing the physical effects of penetrating
different layers of hard mastoid cortex and airfilled
petrous bone with a high-speed drill
(Figure 22, main);
(c) an interface (Figure 22, insert) consisting of a
stereoscopic viewing system and two haptic
feedback stylus-like hand controllers
(PHANTOMs) 28 , capable of reproducing the
force and tactile sensations associated with
mastoidectomy and the vibration-induced
sound effects experienced when drilling
through different densities of bone.
Figure 22: Hybrid fidelity interface solution
for temporal bone surgical training.
Source: Author’s Image Archive
26
Mastoidectomy is a surgical procedure to remove part of the temporal bone behind the ear with the aim of
removing infected bone volumes, to implant assistive hearing technologies, to repair middle or inner ear
structures or to remove deeply-situated tumours.
27
Integrated Environment for Rehearsal and Planning of Surgical Interventions; http://www.crs4.it/vic/cgibin/project-page.cgi?acronym='IERAPSI'.
28
The PHANTOM haptic feedback system was developed by SensAble Technologies (www.sensable.com).