Development of neuronal prosthetics, where neuronal activity is used to control artificial limbs, has so far relied on decoding kinematic parameters of movements, such as movement position or velocity. In addition to kinematic control, proper control of forces exerted by the prosthetic device is necessary for successful interaction with the environment. In our study, we analysed the possibility of classifying and decoding different grasp related forces during active grasping. Two macaque monkeys were trained to reach, grasp and pull an object in response to visual cues. Cues instructed the monkeys to grasp the object with one out of two grip types (precision or side grip) and pull the object with one of two different forces (0.5N or 2N). Monkeys obtained a food reward after successfully performing the instructed grip and pull. During the task execution, we recorded electrophysiological signals from the multielectrode arrays implanted intracortically in the hand and arm area of the monkey’s motor cortex. Six different parameters of the grip: four pressure forces on each side of the object, pull force on the object and the object displacement, were recorded simultaneously with the neuronal activity. Recorded neuronal activity was used to classify different grip types or loading forces, and to decode the continuous traces of different forces during the grip. Our results show that kinetic grip parameters can be decoded with high accuracy, thereby improving the feasibility of constructing fully functional anthropomorphic neuronal prosthesis that relies on kinetic (force) control.

Our thesis project is related to analyze real-time gait analysis of Parkinson's patient in order to actively respond to his non-stable movements. Based on real world data, we have developed a mechanism to implement an algorithm to trigger security alarm to avoid patient from falling. This algorithm is not hard coded i.e. user can set Sampling Rate & Threshold values to analyze motion data for fall avoidance. While other researchers can also utilize this algorithm in their study without need to implement. Maximum gait parameters are also discussed & a 4GB Test is designed first time to take measurements systematically.

A large number of experiments have isolated a coalition of constraints, including cortical and subcortical neural crosstalk, that influence the coordination of the two hands functioning together. Recent findings, however, have demonstrated that these constraints are minimized when integrated feedback (Lissajous feedback) is used. Two experiments were designed to determine participants’ ability to coordinate 1:2 and 2:3 rhythmical bimanual force production tasks. We hypothesized that neural crosstalk should be more easily detected and characterized in tasks where the forces required to produce the goal pattern of coordination are increased. The task was to rhythmically produce and coordinate a pattern of isometric forces. A Lissajous display illustrated the specific pattern of force requirements needed to produce the goal pattern. The results indicated very effective temporal performance of the bimanual coordination patterns. This result is similar to that observed in our earlier work with reciprocal and circling motion, but is especially informative given that the increased forces required to produce the desired bimanual coordination pattern resulted in a consistent and identifiable distortion of the left limb forces that could be attributable to the production of right hand forces. We were not able to detect distortions of the forces produced by the right limb that could be attributable to the left limb. This type of right to left limb influence, which may be attributable to asymmetrical cortical and subcortical crosstalk, was not evident in our earlier work when the bimanual coordination tasks involved movements of the limbs in a relatively frictionless environment.

Fractal time series analysis methods are commonly used for analyzing center of pressure (COP) signals with the goal of revealing the underlying neuromuscular processes for upright stance control. The use of fractal methods is often coupled with the assumption that the COP is an instance of fractional Gaussian noise (fGn) or fractional Brownian motion (fBm). Our purpose was to evaluate the applicability of the fGn-fBm framework to the COP in light of several characteristics of COP signals revealed by a new method, adaptive fractal analysis (AFA; Riley et al., 2012). Our results showed that there are potentially three fractal scaling regions in the COP as opposed to one as expected from a pure fGn or fBm process. The scaling region at the fastest scale was anti-persistent and spanned ~30-90 msec, the intermediate was persistent and spanned ~200 msec-1.9 sec, and the slowest was anti-persistent and spanned ~5-40 sec. The intermediate fractal scaling region was the most clearly defined, but it only contributed around 11% of the total spectral energy of the COP signal, indicating that other features of the COP signal contribute more importantly to the overall dynamics. Also, more than half of the Hurst exponents estimated for the intermediate region were greater than the theoretically expected range [0,1] for fGn-fBm processes. These results suggest the fGn-fBm framework is not appropriate for modeling COP signals. ON-OFF intermittency might provide a better modeling framework for the COP, and multiscale approaches may be more appropriate for analyzing COP data.

INTRODUCTION Central nervous system uses two main strategies to retain balance if it is distorted by a perturbation: (1) feed forward control or anticipatory postural adjustments (APA) prior to the expected body perturbations and (2) feedback control or compensatory postural adjustments (CPA) that are initiated by the sensory feedback signals after the perturbations. Our posture is controlled by the integration of information from the vestibular, proprioceptive, and visual systems. The purpose of this study was to investigate the role of altered proprioception on anticipatory (APAs) and compensatory (CPAs) postural adjustments. METHODS Nine healthy adults received external perturbations at the shoulder level while standing with intact or altered proprioception on an AMTI force platform. Experimental conditions were: normal and altered proprioception while eyes are open or closed. Proprioception was altered bilaterally by applying miniature vibrators over the Achilles tendon. Electrical activity of the trunk and leg muscles and center of pressure (COP) displacements were recorded. RESULTS When vision was available in eyes open condition with altered proprioception, APA was delayed (p<0.05). Moreover, altered proprioceptive information resulted in smaller magnitude of CPA. Smaller COP displacements were recorded after the perturbation in both eyes open and eyes closed conditions. DISCUSSION Alteration of proprioception of the lower extremity in the presence of vision induces significant delays of APA. Moreover, the subjects’ demonstrated that irrespective of the availability of vision, altered proprioception was associated with a reduction of CPA and lesser COP displacements after perturbation.