Motion Feedback Research Articles

Effects of biofeedback on secondary-task response time and postural stability in older adults

Real-time single- and multiple-axis vibrotactile feedback of trunk motion has been shown to significantly decrease mean trunk tilt and decrease time spent outside a no vibrotactile feedback zone (dead zone) in older adults within a laboratory setting. This study aimed to determine if these improvements can translate into everyday use, during which other tasks may simultaneously demand attention. A dual-task paradigm was used in which 10 community-dwelling older adults were asked to perform standing trials in the presence of a secondary task (verbal or push-button), vibrotactile feedback, or both (dual-task). Results show that subjects significantly increased the percentage of time inside the dead zone when feedback was provided compared to when it was not during both verbal (+13.6%) and push-button (+10.1%) secondary tasks. Providing feedback also decreased RMS of trunk tilt during both secondary tasks (verbal: −0.129°; push-button: −0.138°). However, response times for secondary tasks increased (verbal: +119ms; push-button: +110ms) when feedback was provided. These results suggest that while vibrotactile feedback does increase attentional load in older adults, it can still be used effectively to improve postural metrics in high cognitive load situations.

Vision-to-event and movement-to-event coordination in an unimanual circling task

Coordination of actions with events in extracorporeal space is essential for many everyday tasks. In the present study, we investigated how transformations, like in tool use, and varying the spatial context affect action coordination. For this aim, we used a circling task that required participants to coordinate the visual feedback of hand movements with a clockwise circling stimulus (event). The trajectories of stimulus and visual feedback were presented horizontally aligned (group horizontal), within each other (group interleaved) or vertically aligned (group vertical). Within groups, we varied the instructed rotation direction of stimulus and visual feedback (same and different), and y-direction of visual feedback relative to the stimulus (same and different). To dissociate movements and the associated proprioceptive/kinesthetic feedback from visual movement feedback, participants performed the tasks under regular and transformed visual feedback (180° angular shift). Results indicated that action coordination follows the principle of vision-to-event coordination (similar data patterns with regular and transformed feedback), but subtle effects of movement-to-event coordination were also observed (larger difference in performance between same y-direction and different y-direction conditions with regular than with transformed feedback). The presence of a transformation affected performance negatively. The different visual layouts affected the different conditions differentially, pointing to the importance of the visual context. In conclusion, vision-to-event coordination dominates unimanual action coordination. The quality of performance is influenced by perceptual processes based on differential processing of the horizontal and vertical axis, and based on Gestalt principles.

Perceptual calibration to delayed auditory feedback of self-body movement

Temporal contingency between self-body movement and its auditory feedback is crucial to perceive external auditory events. The present study examined whether delay detection of self-generated sound is modulated by short-term exposure of delayed auditory feedback. A total of 36 healthy students participated in Experiment 1 (, age 21.4 ± 1.3 years, mean ± SD) and 2 (, age 20.8 ± 1.4 years). In both experiments, the subject pressed a button with their right index finger and judged whether the auditory feedback (full-range pulsed sound) delivered through a headphone was delayed or not, compared to the sensation of the finger movement. Auditory feedback delay was inserted by using a sound effector device (SPX2000, YAMAHA, Japan). The durations of auditory feedback delay were ranged from 118 to 352 ms at 33.3 ms intervals in Experiment 1, and from 19 to 253 ms in Experiment 2. To calculate the point of subjective equality (PSE), where the delay detection rate was 50%, we have fitted a logistic function to the delay detection probability curve for each subject. The results showed that PSEs were 209.0 and 137.5 ms in Experiment 1 and 2, respectively, which were significantly different (, ). This indicates that PSE was modulated by the range of the delay used in the experiment; PSE became longer as the delay lengthened. We suppose that the perceptual delay in auditory feedback of self-body movement is automatically calibrated to the frequently exposed duration between self-body movement and the auditory feedback.

Attentive documents

Reading is one of the most frequent activities of knowledge workers. Eye tracking can provide information on what document parts users read, and how they were read. This article aims at generating implicit relevance feedback from eye movements that can be used for information retrieval personalization and further applications. We report the findings from two studies which examine the relation between several eye movement measures and user-perceived relevance of read text passages. The results show that the measures are generally noisy, but after personalizing them we find clear relations between the measures and relevance. In addition, the second study demonstrates the effect of using reading behavior as implicit relevance feedback for personalizing search. The results indicate that gaze-based feedback is very useful and can greatly improve the quality of Web search. The article concludes with an outlook introducing attentive documents keeping track of how users consume them. Based on eye movement feedback, we describe a number of possible applications to make working with documents more effective.

Concurrent Visual Feedback and Spatial Accuracy in Continuous Aiming Movements

The effect of concurrent visual feedback (CVF) on continuous aiming movements was investigated in the preferred hand of participants of college age (ns = 12 men, 8 women). Participants made continuous rapid reversal movements with a lightweight lever in the sagittal plane. Participants attempted to reach a short target (20 degrees) and a long target (60 degrees) in separate constant practice conditions, but alternated between the two targets in a variable practice condition. Four blocks of practice trials were provided in each condition, with 40 movements made in each. CVF of the position-time trace was provided for the first 20 movements of each block, but was removed for the remaining 20 movements in each block. Movements were more accurate and consistent during constant practice compared to variable practice where the short target was overshot and the long target was undershot. CVF reduced errors in all conditions, compared to movements without CVF, particularly for the short target during variable practice. The results suggest that the interference generated by alternating targets can be modulated by providing visual feedback, but once the visual feedback was removed, errors increased markedly.

Applied Motion Cueing Strategies for Three Different Types of Motion Systems

Simulators with motion systems are used to give the driver a motion feedback. The type of the motion system and its related motion envelope is a major factor for the ability to present certain motion cues. This paper describes algorithms for three types of motion systems with the focus on a new algorithm for 8-degree-of-freedom systems. As new features compared to other algorithms for this type of motion system consequent complementary splitting into low-, mid-, and high-frequent signals and cross-system washout compensation are introduced. Parameter tuning effects according to washout and signal splitting filter frequency variations are shown and analyzed.

The Effects of Head Movement and Accurate Proprioceptive Feedback in Training of Sound Localization

We investigated the effects of listeners' head movement and proprioceptive feedback on the accuracy of sound localization. The effects were examined under the conditions that their head movement was restricted (study 1) or unrestricted (study 2) on the sound localization training. In both experiments, participants divided into two groups: training group performed the sound localization training with accurate proprioceptive feedback, while control group conducted the training with no-feedback. The results indicated that: (1) sound localization training under active head movements increased the accuracy of sound localization; (2) accurate proprioceptive feedback facilitated the sound localization during the initial training phase; and (3) training with the feedback dominantly decreased the rate of vertical localization errors in sound localization performance.

A charged-particle manipulator utilizing a co-axial tube electrodynamic trap with an integrated camera

A charged-particle manipulator was designed and fabricated with an integrated imaging camera allowing real-time in-situ monitoring of trapped particle motion even when the trap device is under motion or rotation. The trap device was made of two co-axial electrically conductive tubes with diameters of 5.5 mm and 7 mm for the inner tube and outer tube, respectively; the imaging camera with its optical fiber bundle was integrated within the tubular trap device to realize a single instrument functioning as a manipulator. Motion of suspended microparticles of 3 μm to 50 μm in diameter can be monitored using the integrated camera regardless of the trap device orientations. This manipulator provides capability of controlled manipulation of trapped particles by tuning the operating conditions while monitoring the feedback of real-time particle motion. Imaging of suspended particles was not interrupted while the manipulator was translated and/or rotated. This integrated manipulator can be used for charged particle transport and repositioning.

Magnetic endoscopic imaging saves abdominal compression and patient pain in routine colonoscopies

Magnetic endoscope imaging (MEI) is a technique for the direct visualisation of endoscope configuration within the colon. This method may prevent loop formation by giving visual feedback of endoscope movement. This study aimed to evaluate the efficacy of MEI in improving colonoscopy performance. Overall 1000 consecutive patients who underwent a complete routine colonoscopy were randomized into two groups: in group A with MEI, while in group B without MEI. Sedation was performed according to local standards. In both groups time to reach the cecum, the number of positioning maneuvers and involvement of a second assistant nurse were recorded. Abdominal compression was graded from 1 to 4 according to the duration and intensity of compression was quantified using a scale from 1-3 according to compression form and patient reaction. Patients were randomized (group A with MEI, n = 490; group B without MEI, n = 510) and a total colonoscopy was performed. Time to cecal intubation did not differ between the groups (507 s vs 538 s; NS). The duration of abdominal compression was significantly shorter in MEI guided colonoscopy. The intensity of abdominal compression was lower in group A and fewer turn maneuvers needed per patient. A trend towards a reduced need for assistance in MEI group was seen. Although MEI does not generally accelerate colonoscope advancement, it significantly reduces the force and the duration of abdominal compression by assistant personnel, thus minimizing patient discomfort and decreasing the need for additional staff.

Modeling Wide-Frequency-Range Pilot Equalization for Control of Aircraft Pitch Dynamics

In continuous manual control tasks, human controllers adapt their control strategy to the dynamics of the controlled element. This compensation for the controlled-element dynamics is performed around the pilot–vehicle system crossover frequency, in order to obtain satisfactory performance of the combined pilot–vehicle system, but is also seen to extend to frequencies well above crossover. For a controlled element representing the linearized pitch dynamics of a small conventional jet aircraft, an extension to the models for pilot equalization described in the literature was found to be needed for the modeling of the adopted pilot equalization dynamics over a wide frequency range. Measured pilot describing functions revealed that pilots use a combination of low-frequency lag and high-frequency lead equalization to compensate for the characteristics of these typical aircraft pitch dynamics around the short-period mode. An additional high-frequency lead term in the pilot equalization transfer function was found to allow for the modeling of these adopted equalization dynamics over a wide frequency range, thereby also yielding a significant increase in the percentage of measured control inputs that is explained by the pilot model. Furthermore, for this controlled element the extended model for the equalization dynamics was found to be important for the interpretation of the changes in pilot control behavior that occur due to the presence of physical motion feedback.

Investigating the affective quality of interactivity by motion feedback in mobile touchscreen user interfaces

Emotion is a key aspect of user experience. To design a user interface for positive emotional experience, the affective quality of the user interface needs to be carefully considered. A major factor of affective quality in today's user interface for digital media is interactivity, in which motion feedback plays a significant role as an element. This role of motion feedback is particularly evident in touchscreen user interfaces that have been adopted rapidly in mobile devices. This paper presents two empirical studies performed to increase our understanding of motion feedback in terms of affective quality in mobile touchscreen user interfaces. In the first study, the relationships between three general motion properties and a selected set of affective qualities are examined. The results of this study provide a guideline for the design of motion feedback in existing mobile touchscreen user interfaces. The second study explores a new dimension of interactivity that is the Weight factor of Laban's Effort system. To experiment the Weight factor in a mobile touchscreen user interface, a pressure sensitive prototype was developed to recognize the amount of force applied by the user's finger action. With this prototype, the effects of implementing pressure requirements on four different types of user interfaces were examined. Results show that implementing the Weight factor can significantly influence the affective quality and complement the physical feel of a user interface. The issues to consider for effective implementation are also discussed.

The fusimotor and reafferent origin of the sense of force and weight

Signals associated with the command the brain sends to muscles are thought to create the sensation of heaviness when we lift an object. Thus, as a muscle is weakened by fatigue or partial paralysis (neuromuscular blockade), the increase in the motor command needed to lift a weight is thought to explain the increasing subjective heaviness of the lifted object.With different fatiguing contractions we approximately halved the force output of the thumb flexor muscles, which were then used to lift an object. For two deafferented subjects the perceived heaviness of the lifted object approximately doubled, in keeping with the central-signal theory. However, for normal subjects this resulted in objects feeling the same or lighter, inconsistent with the central-signal theory but consistent with the expected effects of the conditioning contractions on the sensitivity of peripheral receptors. In separate experiments we subjected the forearm muscles to complete paralysis with a non-depolarising neuromuscular blocking agent and then allowed them to recover to approximately half-force output. This also resulted in objects feeling lighter when lifted by the semi-paralysed thumb, even though the motor command to the motoneurons must have been greater. This is readily explained by reduced lift-related reafference caused by the prolonged paralysis of muscle spindle intrafusal fibres.We conclude that peripheral signals, including a major contribution from muscle spindles, normally give rise to the sense of exerted force. In concept, however, reafference from peripheral receptors may also be considered a centrally generated signal that traverses efferent and then afferent pathways to feed perceptual centres rather than one confined entirely to the central nervous system. These results therefore challenge the distinction between central- and peripheral-based perception, and the concept that muscle spindles provide only information about limb position and movement.

A perioral dynamic model for investigating human speech articulation

A multibody system called the perioral dynamic model for investigating dynamic behavior of human speech articulator is presented. The model is based on the biomechanical architecture of human speech articulators, consisting of the soft tissue around the lips, the related muscles, and the jaw bone structure. The dynamic consequence of human speech articulation is revealed as a sequential perioral motion induced by the selectively activated muscle actions. As an anatomically consistent biomechanical platform, the perioral dynamic model is designed to represent the rigid jaw motion as well as the perioral soft tissue deformation interacting with each other. The perioral soft tissue in the model is approximated as a discrete particle system consisting of lumped point masses interconnecting with adjacent ones via viscoelastic elements. To ensure continuum-compatible static deformation in the discrete particle system, we introduce a method of adjusting element stiffness. We also present a new method for determining the effective forces acting on the jaw-bone-attached nodes that transforms jaw dynamics in the rigid body system into the one defined in the discrete particle system, keeping dynamic equivalency and equipollency between two systems. To derive muscle activations which let the developed dynamic model produce a simulated perioral motion mimicking an actual human speech behavior, we present an inverse dynamics technique driven by visual observation-based feedback of an actual lip motion.

Driver Behavior Comparison Between Static and Dynamic Simulation for Advanced Driving Maneuvers

In advanced driving maneuvers, such as a slalom maneuver, it is assumed that drivers use all the available cues to optimize their driving performance. For example, in curve driving, drivers use lateral acceleration to adjust car velocity. The same result can be found in driving simulation. However, for comparable curves, drivers drove faster in fixed-base simulators than when actually driving a car. This difference in driving behavior decreases with the use of inertial motion feedback in simulators. The literature suggests that the beneficial effect of inertial cues in driving behavior increases with the difficulty of the maneuver. Therefore, for an extreme maneuver such as a fast slalom, a change in driving behavior is expected when a fixed-base condition is compared to a condition with inertial motion. It is hypothesized that driving behavior in a simulator changes when motion cues are present in extreme maneuvers. To test the hypothesis, a comparison between No-Motion and Motion car driving simulation was done, by measuring driving behavior in a fast slalom. A within-subjects design was used, with 20 subjects driving the fast slalom in both conditions. The average speed during the Motion condition was significantly lower than the average speed during the No-Motion condition. The same was found for the peak lateral acceleration generated by the car model. A power spectral density analysis performed on the steering wheel angle signal showed different control input behavior between the two experimental conditions. In addition, the results from a paired comparison showed that subjects preferred driving with motion feedback. From the lower driving speed and different control input on the steering wheel, we concluded that motion feedback led to a significant change in driving behavior.

2P2-D04 神経-筋相互作用により運動発達する生体ロボティクス : 培養神経ネットワークによる筋組織の運動制御(リハビリテーションロボティクス・メカトロニクス)

We proposed a novel bio robotic application which has almost the same dynamics as that of the neuromuscular control system to understand biological systems. This bio robot consists of culture neuronal network and muscle-powered actuator to mimic living creatures. Through the computer, culture neural activities are transported to muscle-powered actuator as electrical signals, and muscle activities are fed back to culture neurons as motion capture images. Living neurons were cultured on multielectrode array to measure neural signals. Living muscle tissues were engineered from muscle cells as driving source of the actuator. A SU-8 microgripper, which was fabricated as a structure of muscle-powered actuator, was assembled with a living muscle tissue. We successfully controlled the muscle-powered SU-8 microgripper with electrical stimulation mimicked neural signals. Moreover, we could construct real time motion feedback system of muscle-powered actuator with optical flow.

Benefits of ego motion feedback for interactive experiments in virtual reality scenarios

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Learning Combinatorial Map Information from Permutations of Landmarks

This paper considers a robot that moves in the plane and that is able to sense only the cyclic order of landmarks with respect to its current position. No metric information is available regarding the robot or landmark positions; moreover, the robot does not have a compass or odometers (i.e., knowledge of coordinates). We carefully study the information space of the robot, and establish its capabilities in terms of mapping the environment and accomplishing tasks, such as navigation and patrolling. When the robot moves exclusively inside the perimeter of the set of landmarks, the information space may be succinctly characterized as an order type that provides information powerful enough to determine which points lie inside the convex hulls of subsets of landmarks. In addition, if the robot is allowed to move outside the perimeter of the set of landmarks, the information space is described with a swap cell decomposition, that is, an aspect graph in which each aspect is a cyclic permutation of landmarks. Finally, we show how to construct such decomposition through its dual, using two kinds of feedback motion commands based on the landmarks sensed.

Development of Frameless SRS using Real-Time 6D Facial Surface Monitoring and Continuous Adaptive Head Motion Correction

Development of Frameless SRS using Real-Time 6D Facial Surface Monitoring and Continuous Adaptive Head Motion Correction

3-Dimensional pose sensor algorithm for humanoid robot

In this paper, a 3D pose attitude estimation system using inertial sensors was developed to provide feedback motion and attitude information for a humanoid robot. It has a very effective switching structure and composed of three modules, a motion acceleration detector, a pseudo-accelerometer output estimator, and a linear acceleration estimator. The switching structure based on probability enables a tactful feedback loop for the extended Kalman filter inside the sensor system. Specially designed linear-rotation test equipment was built, and the experimental results showed its fast convergence to actual values in addition to its excellent responses. The output of the proposed 3D sensor can be transmitted to a humanoid at a frequency of 200 Hz.

A Dynamic Region-of-Interest Vision Tracking System Applied to the Real-Time Wing Kinematic Analysis of TetheredDrosophila

Tracking objects that move fast with respect to their size is challenging because it necessitates large field of views often incompatible with the required spatial and temporal resolutions. Here, we present a novel computer vision system that overcomes this tradeoff by employing a camera with dynamic region-of-interest (ROI) capabilities, combined with an efficient predictive approach. We apply this method to extract the wing kinematics of tethered flying fruit flies in real time. At each frame, only the pixels immediately surrounding the wing are exposed, and the wing position is extracted. It is then fed to an extended Kalman filter that extracts four key parameters of the measurement time-course and, therefore, provides real-time feedback of wing motion. Using this approach, we are able to sample the wing position of both wings at 7 kHz in a 2500 pixel ROI. Our methods promise new applications that can be implemented in general purpose digital hardware for high performance tracking and process control in a broad range of applications in technology and science.