Matching Items (6)

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A Mechanical Analysis of Trained Violinist Kinematics

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Central to current conceptions concerning the function of the nervous system is the consideration of how it manages to maintain precise control for repetitive tasks such as reaching, given the

Central to current conceptions concerning the function of the nervous system is the consideration of how it manages to maintain precise control for repetitive tasks such as reaching, given the extensive observable mechanical degrees of freedom. Especially in the upper extremities, there are an infinite number of orientations (degrees of freedom) that can produce the same ultimate outcome. Consider, for example, a man in a seated position pointing to an object on a table with his index finger: even if we vastly simplify the mechanics involved in that action by considering three principle joints - the shoulder, elbow, and wrist - there are an infinite number of upper arm orientations that would result in the same position of the man's index finger in three-dimensional space. It has been hypothesized that the central nervous system is capable of simplifying reaching tasks by organizing the DOFs; this suggests that repetitive, simple tasks such as reaching can be planned, that the variability in repetitive tasks is minimized, and that the central nervous system is capable of increasing stability by instantaneously resisting perturbations. Previous literature indicates that variability is decreased and stability increased in trained upper extremity movement. In this study, mechanical discrepancies between violinists of varying levels of experience were identified. It was hypothesized that variability in the positional error (deviation from an expected line of motion) and velocity of the bow, as well as the produced variability in resultant elbow angles, would decrease with increasing proficiency, and that training would have no observable effect on average peak bow velocity. Data acquisition was accomplished by constructing LED triads and implementing a PhaseSpace 3D Motion Capture system. While the positional variance and peak velocity magnitude of the bow appeared unaffected by training (p >> 0.05), more advanced players demonstrated significantly higher variability in bow velocity (p << 0.001). As such, it can be concluded that repetitive training does manifest in changes in variability; however, further investigation is required to reveal the nature of these changes.

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  • 2018-05

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Analysis of Applied Thumb and Index Force in Trained and Untrained Violinists

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The purpose of this experiment is to study whether there is a difference in applied finger force between violinists of different skill proficiencies. It has been hypothesized that more experienced

The purpose of this experiment is to study whether there is a difference in applied finger force between violinists of different skill proficiencies. It has been hypothesized that more experienced violinists will apply less force during play in their thumb and index fingers. It was found that there was significant difference in the peak forces applied by the index finger, thumb, and grip (p < 0.05) in all groups except beginner and intermediate violinists in peak thumb force. Significant differences were also found in the continuous force applied by the index finger and grip as well as the standard deviation of the continuous force applied by the thumb (p < 0.05). Additionally, there were no significant differences in the correlation between continuous applied index finger and thumb forces or latency in index and thumb force between different levels or proficiencies (p > 0.05). Due to these results, the hypothesis could not be fully accepted signifying that further testing must be performed.

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  • 2018-05

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The effects of square breathing as a vagal nerve stimulant on learning new motor strategies in unreliable proprioceptive conditions

Description

Lack of proprioceptive feedback is one cause for the high upper-limb prosthesis abandonment rate. The lack of environmental interaction normalcy from unreliable proprioception creates dissatisfaction among prosthesis users. The purpose

Lack of proprioceptive feedback is one cause for the high upper-limb prosthesis abandonment rate. The lack of environmental interaction normalcy from unreliable proprioception creates dissatisfaction among prosthesis users. The purpose of this experiment is to investigate the effects of square breathing on learning to navigate without reliable proprioception. Square breathing is thought to influence the vagus nerve which is linked to increased learning rates. In this experiment, participants were instructed to reach toward targets in a semi-immersive virtual reality environment. Directional error, peak velocity, and peak acceleration of the reaching hand were investigated before and after participants underwent square breathing training. As the results of<br/>this experiment are inconclusive, further investigation needs to be done with larger sample sizes and examining unperturbed data to fully understand the effects of square breathing on learning new motor strategies in unreliable proprioceptive conditions.

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  • 2021-05

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The Role of Precision Grip Aperture in Hardness Differentiation of Cube-Like Objects

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Determining the characteristics of an object during a grasping task requires a combination of mechanoreceptors in the muscles and fingertips. The width of a person's finger aperture during the gras

Determining the characteristics of an object during a grasping task requires a combination of mechanoreceptors in the muscles and fingertips. The width of a person's finger aperture during the grasp may affect the accuracy of how that person determines hardness, as well. These experiments aim to investigate how an individual perceives hardness amongst a gradient of varying hardness levels. The trend in the responses is assumed to follow a general psychometric function. This will provide information about subjects' abilities to differentiate between two largely different objects, and their tendencies towards guess-chances upon the presentation of two similar objects. After obtaining this data, it is then important to additionally test varying finger apertures in an object-grasping task. This will allow an insight into the effect of aperture on the obtained psychometric function, thus ultimately providing information about tactile and haptic feedback for further application in neuroprosthetic devices. Three separate experiments were performed in order to test the effect of finger aperture on object hardness differentiation. The first experiment tested a one-finger pressing motion among a hardness gradient of ballistic gelatin cubes. Subjects were asked to compare the hardness of one cube to another, which produced the S-curve that accurately portrayed the psychometric function. The second experiment utilized the Phantom haptic device in a similar setup, using the precision grip grasping motion, instead. This showed a more linear curve; the percentage reported harder increased as the hardness of the second presented cube increased, which was attributed to both the experimental setup limitations and the scale of the general hardness gradient. The third experiment then progressed to test the effect of three finger apertures in the same experimental setup. By providing three separate testing scenarios in the precision grip task, the experiment demonstrated that the level of finger aperture has no significant effect on an individual's ability to perceive hardness.

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  • 2015-05

A robot hand testbed designed for enhancing embodiment and functional neurorehabilitation of body schema in subjects with upper limb impairment or loss

Description

Many upper limb amputees experience an incessant, post-amputation “phantom limb pain” and report that their missing limbs feel paralyzed in an uncomfortable posture. One hypothesis is that efferent commands no

Many upper limb amputees experience an incessant, post-amputation “phantom limb pain” and report that their missing limbs feel paralyzed in an uncomfortable posture. One hypothesis is that efferent commands no longer generate expected afferent signals, such as proprioceptive feedback from changes in limb configuration, and that the mismatch of motor commands and visual feedback is interpreted as pain. Non-invasive therapeutic techniques for treating phantom limb pain, such as mirror visual feedback (MVF), rely on visualizations of postural changes. Advances in neural interfaces for artificial sensory feedback now make it possible to combine MVF with a high-tech “rubber hand” illusion, in which subjects develop a sense of embodiment with a fake hand when subjected to congruent visual and somatosensory feedback. We discuss clinical benefits that could arise from the confluence of known concepts such as MVF and the rubber hand illusion, and new technologies such as neural interfaces for sensory feedback and highly sensorized robot hand testbeds, such as the “BairClaw” presented here. Our multi-articulating, anthropomorphic robot testbed can be used to study proprioceptive and tactile sensory stimuli during physical finger–object interactions. Conceived for artificial grasp, manipulation, and haptic exploration, the BairClaw could also be used for future studies on the neurorehabilitation of somatosensory disorders due to upper limb impairment or loss. A remote actuation system enables the modular control of tendon-driven hands. The artificial proprioception system enables direct measurement of joint angles and tendon tensions while temperature, vibration, and skin deformation are provided by a multimodal tactile sensor. The provision of multimodal sensory feedback that is spatiotemporally consistent with commanded actions could lead to benefits such as reduced phantom limb pain, and increased prosthesis use due to improved functionality and reduced cognitive burden.

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Date Created
  • 2015-02-19

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Effects of Trigeminal Nerve Stimulation on the ANS and Proprioception: High Frequency TNS Reduces Proprioceptive End-point Error

Description

Previously accomplished research examined sensory integration between upper limb proprioception and tactile sensation. The active proprioceptive-tactile relationship points towards an opportunity to examine neuromodulation effects on sensory integration with respect

Previously accomplished research examined sensory integration between upper limb proprioception and tactile sensation. The active proprioceptive-tactile relationship points towards an opportunity to examine neuromodulation effects on sensory integration with respect to proprioceptive error magnitude and direction. Efforts to improve focus and attention during upper limb proprioceptive tasks results in a decrease of proprioceptive error magnitudes and greater endpoint accuracy. Increased focus and attention can also be correlated to neurophysiological activity in the Locus Coeruleus (LC) during a variety of mental tasks. Through non-invasive trigeminal nerve stimulation, it may be possible to affect the activity of the LC and induce improvements in arousal and attention that would assist in proprioceptive estimation. The trigeminal nerve projects to the LC through the mesencephalic nucleus of the trigeminal complex, providing a pathway similar to the effects seen from vagus nerve stimulation. In this experiment, the effect of trigeminal nerve stimulation (TNS) on proprioceptive ability is evaluated by the proprioceptive estimation error magnitude and direction, while LC activation via autonomic pathways is indirectly measured using pupil diameter, pupil recovery time, and pupil velocity. TNS decreases proprioceptive error magnitude in 59% of subjects, while having no measurable impact on proprioceptive strategy. Autonomic nervous system changes were observed in 88% of subjects, with mostly parasympathetic activation and a mixed sympathetic effect.

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Date Created
  • 2019