Training for colonoscopy, which is the examination and treatment of the colon, is often performed... more Training for colonoscopy, which is the examination and treatment of the colon, is often performed on real patients once the physician has passed the novice level. This increases the risk to the patient and lengthens the procedure time. Since a decade ago, there has been research on virtual reality surgery simulators with haptic feedback. The main goal is to provide an alternative to traditional training methods on animals, cadavers or real patients. Haptic feedback is a key feature for every surgery simulator for the training of hand-eye coordination. In this paper, a compact and portable haptic interface is presented for the colonoscopy. The haptic interface provides position data acquisition and force feedback in linear and rotational directions with combined electrical motors and passive brakes to cover a large range of forces. The motorized drives are used for active force feedback and friction compensation and the brakes are used for high force rendering without slipping. This novel design allows decoupled motion in both directions.
How to cite this article: Shokur, S. et al. Assimilation of virtual legs and perception of floor ... more How to cite this article: Shokur, S. et al. Assimilation of virtual legs and perception of floor texture by complete paraplegic patients receiving artificial tactile feedback.
Realistic body images (avatars) have been long utilized in virtual reality applications, and they... more Realistic body images (avatars) have been long utilized in virtual reality applications, and they are becoming increasingly used in Neuroscience and Neuroprosthetics fields. To elucidate monkeys' perception of avatars, we have measured reaction of two naive rhesus monkeys when confronted to realistic 3D monkey avatars with different facial expressions and different levels of realism. We have compared it with their reaction to images of real monkeys with similar facial expressions. Monkeys were initially overtrained in reaching task in which they manipulated a joystick to reach toward circular targets with a computer cursor. We then replaced every 15th target with a randomly selected image of either a real monkey face, an avatar face or a sphere (i.e., control image), and we measured the average speed to reach each of these images. We also tested two different facial expressions: an aggressive bared teeth face and a friendly face. Showing the face images significantly altered the kinematics of reaching movements. These results indicated that monkeys interacted with the realistic avatar as if it was a conspecific. This effect was absent if the avatar was not textured. The two way Anova showed that the interaction of texture and facial expression was a significant factor for monkeys' speed of reaching (p 0.8), suggesting that the texture is more important than spatial realism for Monkeys to consider an avatar as a conspesific. These effects should be taken into account when using avatars in primate neuroprosthetic research.
Minimally invasive surgical approaches have revolutionized surgical care and considerably improve... more Minimally invasive surgical approaches have revolutionized surgical care and considerably improved surgical outcomes. The instrumentation has changed significantly from open to laparoscopic and robotic surgery with various usability and ergonomics qualities. To establish guidelines for future designing of surgical instruments, this study assesses the effects of current surgical approaches and instruments on the surgeon. Furthermore, an analysis of surgeons' preferences with respect to instrument handles was performed to identify the main acceptance criteria. In all, 49 surgeons (24 with robotic surgery experience, 25 without) completed the survey about physical discomfort and working conditions. The respondents evaluated comfort, intuitiveness, precision, and stability of 7 instrument handles. Robotic surgery procedures generally take a longer time than conventional procedures but result in less back, shoulder, and wrist pain; 28% of surgeons complained about finger and neck pain during robotic surgery. Three handles (conventional needle holder, da Vinci wrist, and joystick-like handle) received significantly higher scores for most of the proposed criteria. The handle preference is best explained by a regression model related only to comfort and precision (R(2) = 0.91) and is significantly affected by the surgeon's background (P < .001). Although robotic surgery seems to alleviate physical discomfort during and after surgery, the results of this study show that there is room for improvement in the sitting posture and in the ergonomics of the handles. Comfort and precision have been found to be the most important aspects for the surgeon's choice of an instrument handle. Furthermore, surgeons' professional background should be considered when designing novel surgical instruments.
A novel technology for glass microstructuration called spark assisted chemical engraving (SACE) i... more A novel technology for glass microstructuration called spark assisted chemical engraving (SACE) is presented. This technology is based on electrochemical discharge phenomena. Beyond a critical voltage, electrical discharges occur through the gas film around the electrode and the glass machining is possible. The SACE process is similar to the electrode effects. SACE has been analysed using an electrochemical approach (U-I plots), the experimental results clarify the onset of the discharge activity. Additionally, two theoretical models of the SACE phenomenon were introduced. Firstly a model, based on percolation theory, is briefly described and predicts the critical parameters (voltage and current). Secondly a method to estimate the spark's characteristics (amplitude and duration) is presented and with the help of these data the machining depth was estimated by a numerical simulation. Finally, some glass microstructuring examples are presented to show the potential of this technology.
COVER ILLUSTRATION: The neural mechanisms of brain‐machine interface (BMI) control. By recording ... more COVER ILLUSTRATION: The neural mechanisms of brain‐machine interface (BMI) control. By recording fMRI data while participants controlled an EEG‐based BMI inside the scanner, it was possible to identify an extended cortical‐subcortical network of brain regions active during BMI‐control, as well as the regions associated with the sense of agency for BMI actions.
International Conference on Control, Automation and Systems, 2005
Keywords: [MEDICAL] Reference LSRO-CONF-2006-052 Record created on 2006-06-12, modified on 2017-1... more Keywords: [MEDICAL] Reference LSRO-CONF-2006-052 Record created on 2006-06-12, modified on 2017-11-20
Ligament balancing in total knee arthroplasty is believed to have an important influence on the j... more Ligament balancing in total knee arthroplasty is believed to have an important influence on the joint stability and prosthesis lifetime. In order to provide quantitative information and assistance during the ligament balancing phase, a device that intraoperatively measures knee joint forces and moments has been developed.
Training for colonoscopy, which is the examination and treatment of the colon, is often performed... more Training for colonoscopy, which is the examination and treatment of the colon, is often performed on real patients once the physician has passed the novice level. This increases the risk to the patient and lengthens the procedure time. Since a decade ago, there has been research on virtual reality surgery simulators with haptic feedback. The main goal is to provide an alternative to traditional training methods on animals, cadavers or real patients. Haptic feedback is a key feature for every surgery simulator for the training of hand-eye coordination. In this paper, a compact and portable haptic interface is presented for the colonoscopy. The haptic interface provides position data acquisition and force feedback in linear and rotational directions with combined electrical motors and passive brakes to cover a large range of forces. The motorized drives are used for active force feedback and friction compensation and the brakes are used for high force rendering without slipping. This novel design allows decoupled motion in both directions.
How to cite this article: Shokur, S. et al. Assimilation of virtual legs and perception of floor ... more How to cite this article: Shokur, S. et al. Assimilation of virtual legs and perception of floor texture by complete paraplegic patients receiving artificial tactile feedback.
Realistic body images (avatars) have been long utilized in virtual reality applications, and they... more Realistic body images (avatars) have been long utilized in virtual reality applications, and they are becoming increasingly used in Neuroscience and Neuroprosthetics fields. To elucidate monkeys' perception of avatars, we have measured reaction of two naive rhesus monkeys when confronted to realistic 3D monkey avatars with different facial expressions and different levels of realism. We have compared it with their reaction to images of real monkeys with similar facial expressions. Monkeys were initially overtrained in reaching task in which they manipulated a joystick to reach toward circular targets with a computer cursor. We then replaced every 15th target with a randomly selected image of either a real monkey face, an avatar face or a sphere (i.e., control image), and we measured the average speed to reach each of these images. We also tested two different facial expressions: an aggressive bared teeth face and a friendly face. Showing the face images significantly altered the kinematics of reaching movements. These results indicated that monkeys interacted with the realistic avatar as if it was a conspecific. This effect was absent if the avatar was not textured. The two way Anova showed that the interaction of texture and facial expression was a significant factor for monkeys' speed of reaching (p 0.8), suggesting that the texture is more important than spatial realism for Monkeys to consider an avatar as a conspesific. These effects should be taken into account when using avatars in primate neuroprosthetic research.
Minimally invasive surgical approaches have revolutionized surgical care and considerably improve... more Minimally invasive surgical approaches have revolutionized surgical care and considerably improved surgical outcomes. The instrumentation has changed significantly from open to laparoscopic and robotic surgery with various usability and ergonomics qualities. To establish guidelines for future designing of surgical instruments, this study assesses the effects of current surgical approaches and instruments on the surgeon. Furthermore, an analysis of surgeons' preferences with respect to instrument handles was performed to identify the main acceptance criteria. In all, 49 surgeons (24 with robotic surgery experience, 25 without) completed the survey about physical discomfort and working conditions. The respondents evaluated comfort, intuitiveness, precision, and stability of 7 instrument handles. Robotic surgery procedures generally take a longer time than conventional procedures but result in less back, shoulder, and wrist pain; 28% of surgeons complained about finger and neck pain during robotic surgery. Three handles (conventional needle holder, da Vinci wrist, and joystick-like handle) received significantly higher scores for most of the proposed criteria. The handle preference is best explained by a regression model related only to comfort and precision (R(2) = 0.91) and is significantly affected by the surgeon's background (P < .001). Although robotic surgery seems to alleviate physical discomfort during and after surgery, the results of this study show that there is room for improvement in the sitting posture and in the ergonomics of the handles. Comfort and precision have been found to be the most important aspects for the surgeon's choice of an instrument handle. Furthermore, surgeons' professional background should be considered when designing novel surgical instruments.
A novel technology for glass microstructuration called spark assisted chemical engraving (SACE) i... more A novel technology for glass microstructuration called spark assisted chemical engraving (SACE) is presented. This technology is based on electrochemical discharge phenomena. Beyond a critical voltage, electrical discharges occur through the gas film around the electrode and the glass machining is possible. The SACE process is similar to the electrode effects. SACE has been analysed using an electrochemical approach (U-I plots), the experimental results clarify the onset of the discharge activity. Additionally, two theoretical models of the SACE phenomenon were introduced. Firstly a model, based on percolation theory, is briefly described and predicts the critical parameters (voltage and current). Secondly a method to estimate the spark's characteristics (amplitude and duration) is presented and with the help of these data the machining depth was estimated by a numerical simulation. Finally, some glass microstructuring examples are presented to show the potential of this technology.
COVER ILLUSTRATION: The neural mechanisms of brain‐machine interface (BMI) control. By recording ... more COVER ILLUSTRATION: The neural mechanisms of brain‐machine interface (BMI) control. By recording fMRI data while participants controlled an EEG‐based BMI inside the scanner, it was possible to identify an extended cortical‐subcortical network of brain regions active during BMI‐control, as well as the regions associated with the sense of agency for BMI actions.
International Conference on Control, Automation and Systems, 2005
Keywords: [MEDICAL] Reference LSRO-CONF-2006-052 Record created on 2006-06-12, modified on 2017-1... more Keywords: [MEDICAL] Reference LSRO-CONF-2006-052 Record created on 2006-06-12, modified on 2017-11-20
Ligament balancing in total knee arthroplasty is believed to have an important influence on the j... more Ligament balancing in total knee arthroplasty is believed to have an important influence on the joint stability and prosthesis lifetime. In order to provide quantitative information and assistance during the ligament balancing phase, a device that intraoperatively measures knee joint forces and moments has been developed.
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