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Development and evaluation of Point of Care Ultrasound (PoCUS) skill is a resource intensive undertaking. Current practice involves expert supervision of trainees performing numerous practice scans in the clinical setting. Computer augmented training represents the potential for significant reduction in resources utilization. Multiple ultrasound training simulators exist however of unclear value in teaching image generation skills. This paper describes the concept of using a standard ultrasound machine and human subjects, combined with image processing and depth sensing technologies, to develop a realistic PoCUS training tool. In addition to the concept, we describe the initial data collection experiment and preliminary work integrating ultrasound imagery and probe movement. Operator assessment metrics explored in this paper include image quality, stability, and acquisition time, demonstrate good potential to differentiate between novice and experienced sonographers.

The purpose of these experiments was to investigate the minimum duration of haptic memory representations. The term haptic memory can be defined as the ability to retain impressions of haptically acquired information after the original stimulus is absent. Participants repeatedly picked up objects of various masses. The time interval between the final practice lift of each object and a test lift was manipulated. In the 0 second delay condition, there was no delay between the release of the object after the final practice lift and the test lift. In the 2 and 10 second delay conditions there was a 2 or 10 second delay, respectively, between the release of the object after the last practice lift, and the test lift. Greater peak grip force was produced for the first lift compared to the subsequent practice lifts. In the 0 second delay condition, the peak grip force used in the test lift was similar to the last practice lift. As the delay increased to 10 seconds, the peak grip forces used were similar to that of the first lift. Even after a 2 second delay the peak grip force was greater than that of the last practice lift. Peak torque also followed these same patterns. The present results suggest that the haptic representation of object mass is short-lived (≪ 2 s) and has a duration and decay similar to visual iconic memory.

This study investigated the effects of thermal and frictional cues during a forced-choice material identification task. Thermal properties of the three materials presented (pine, Lexan, aluminum) were conveyed using either real materials or a temperature-controlled aluminum pad to simulate real material effusivities. Friction either varied for the real materials presented, or was constant when the temperature-controlled aluminum simulation pad was presented. Experiments 1 and 2 employed natural materials, while experiments 3 and 4 involved thermal simulations. Thermal cues alone were allowed in experiments 1 and 3 by allowing participants only static exploration with the index finger, with cutaneous contact only in the normal direction. In Experiments 2 and 4, there was dynamic exploration by lateral stroking of the index finger, allowing both thermal and friction cues to be transmitted. Dependent measures included a judgment of the material that was explored, as well as contact forces. The simulation of material effusivity was shown to be valid as participants had identification accuracies that were similar to real materials during static exploration. Material identification accuracy was higher when congruent cues were presented and was lower when incongruent cues were presented. Peak normal force was higher during static exploration, compared to dynamic. These results were interpreted in terms of a framework of single modality competition and cooperation.