Evaluation of voice control, touch panel control and assistant control during steering of an endoscope.

The increasing amount of equipment used in the Operating Room (OR) asks for ergonomical user interfaces. The aim of this study was to investigate in a pelvi-trainer setting the efficiency, reliability and user satisfaction of voice control, touch panel control and conventional manual control by an assistant. Ten subjects had to control the zoom and light intensity of an endoscope, using voice, a touch panel or an assistant. For each interface, the subject received nine tasks to control to a certain level, light, zoom or both. The experiment was repeated three times (three cycles) and the sequences of interfaces were varied per cycle. Experiments were recorded on video and off-line time needed per task and the number of wrongly interpreted tasks were measured. A questionnaire was used to investigate user satisfaction. Voice control was slower than assistant control and touch panel control (92.5 s, 80.2 s and 76.0 s, respectively, p<0.02). There was no significant difference between touch panel control and assistant control. With voice control, 3.1% of the commands were not interpreted and 1.7% were wrongly interpreted. 40% of the subjects experienced voice control as the quickest, 30% touch panel control and 30% assistant control. 48% of the subjects preferred voice control, 28% the touch panel and 24% assistant control. Voice control was less efficient than touch panel control and manual control by an assistant. The subjects experienced voice control as more efficient, however. In the future, voice control should be improved to overcome wrongly interpreted commands. Furthermore, experiments should be performed in a clinical setting in which the surgeon has to perform two-handed tasks to evaluate the effects on the surgeon's performance.