Non-Invasive Stable Sensory Feedback for Closed-Loop Control of Hand Prosthesis

Predictive Warning of Nociceptive Temperature during Prosthetic Hand Prehension. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023;2023:1-4. [PMID: 38082868 DOI: 10.1109/embc40787.2023.10340994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Grasping hot objects may be harmful, and a warning of nociceptive temperature should be provided to prevent prosthetic hands from damage. This study developed a fast algorithm to predict the steady state temperature of grasped objects based on a thermoresistant sensor, and verified a bi-state sensory encoding strategy to inform either contact force or nociceptive temperature at prosthetic finger. Below the threshold, a buzz percept was used to encode fingertip force, and above the threshold, a tingling pain sensation was induced to warn harmful temperature. This sensory encoding mechanism was tested in one able-bodied subject with a psychophysical experimental paradigm. Results indicated that fast identification of the steady state temperature could be achieved in 0.75±0.00 s with an error of 8.3±6.0%. The subject was able to recognize whether the object temperature was above or below the threshold of nociceptive temperature with an average success rate of 98.2% and 97.0%, respectively. The action to release the tube could be executed in 0.80±0.32 s. The reaction time of successful identification and execution was 1.55 ± 0.32 s. The probability that a release reaction was triggered at the threshold of 60.0°C was calculated with tube temperatures varying from 30.0°C to 80.0°C. The 50% percentile point on the fitted stimulus-response curve corresponded to a temperature of 59.5°C, nearly identical to the internally set threshold. The psychophysical behavior test verified the sensory function to recognize and notify unsafe temperatures in real time.Clinical Relevance-The method of identifying and alerting nociceptive temperatures may restore the sensory ability of amputees to avoid potential damage of grasping hot objects with a prosthetic hand in activities of daily life.