Matching Items (4)
Filtering by

Clear all filters

156964-Thumbnail Image.png
Description
Proprioception is the sense of body position, movement, force, and effort. Loss of proprioception can affect planning and control of limb and body movements, negatively impacting activities of daily living and quality of life. Assessments employing planar robots have shown that proprioceptive sensitivity is directionally dependent within the horizontal plane

Proprioception is the sense of body position, movement, force, and effort. Loss of proprioception can affect planning and control of limb and body movements, negatively impacting activities of daily living and quality of life. Assessments employing planar robots have shown that proprioceptive sensitivity is directionally dependent within the horizontal plane however, few studies have looked at proprioceptive sensitivity in 3d space. In addition, the extent to which proprioceptive sensitivity is modifiable by factors such as exogenous neuromodulation is unclear. To investigate proprioceptive sensitivity in 3d we developed a novel experimental paradigm employing a 7-DoF robot arm, which enables reliable testing of arm proprioception along arbitrary paths in 3d space, including vertical motion which has previously been neglected. A participant’s right arm was coupled to a trough held by the robot that stabilized the wrist and forearm, allowing for changes in configuration only at the elbow and shoulder. Sensitivity to imposed displacements of the endpoint of the arm were evaluated using a “same/different” task, where participant’s hands were moved 1-4 cm from a previously visited reference position. A measure of sensitivity (d’) was compared across 6 movement directions and between 2 postures. For all directions, sensitivity increased monotonically as the distance from the reference location increased. Sensitivity was also shown to be anisotropic (directionally dependent) which has implications for our understanding of the planning and control of reaching movements in 3d space.

The effect of neuromodulation on proprioceptive sensitivity was assessed using transcutaneous electrical nerve stimulation (TENS), which has been shown to have beneficial effects on human cognitive and sensorimotor performance in other contexts. In this pilot study the effects of two frequencies (30hz and 300hz) and three electrode configurations were examined. No effect of electrode configuration was found, however sensitivity with 30hz stimulation was significantly lower than with 300hz stimulation (which was similar to sensitivity without stimulation). Although TENS was shown to modulate proprioceptive sensitivity, additional experiments are required to determine if TENS can produce enhancement rather than depression of sensitivity which would have positive implications for rehabilitation of proprioceptive deficits arising from stroke and other disorders.
ContributorsKlein, Joshua (Author) / Buneo, Christopher (Thesis advisor) / Helms-Tillery, Stephen (Committee member) / Kleim, Jeffrey (Committee member) / Santello, Marco (Committee member) / Arizona State University (Publisher)
Created2018
134674-Thumbnail Image.png
Description
Background. Proprioception plays a large role in everyday functioning, involving both information of body position and movement (Johnson & Panayotis, 2010). Clinical assessments of proprioception are largely subjective and are not reliable measures for testing proprioception in impaired or unimpaired individuals. Recent advancements in technology and robotics have brought about

Background. Proprioception plays a large role in everyday functioning, involving both information of body position and movement (Johnson & Panayotis, 2010). Clinical assessments of proprioception are largely subjective and are not reliable measures for testing proprioception in impaired or unimpaired individuals. Recent advancements in technology and robotics have brought about new assessments that involve position matching and other paradigms. However, the results are confined to the horizontal plane and only look at a very small subset of human proprioceptive ability. Objective. The present study looks to overcome these limitations and examine differences in proprioceptive sensitivity across different directions in 3D space. Methods. Participants were recruited from Arizona State University to perform a "same-different" discrimination test using a robotic arm. Each participant was tested along two of the three directions, and within each direction, proprioception at four distances (1-4 cm) was tested. Performance was quantified using percent correct, d' analysis, and permutation testing on median and variance values. Results. Proprioceptive sensitivity was significantly greater in the up direction vs. down and back across all distances. The greatest difference in sensitivity occurred at 3 cm; permutation tests using median and variance values from percent correct and d' found statistical significance at this distance in the up vs. down and up vs. back comparisons. Conclusions. There is evidence that proprioceptive sensitivity is greater in an anti-gravity direction (up), in comparison to gravity-assisted or gravity-neutral (down and back) directions.
ContributorsPatel, Megha (Author) / Buneo, Christopher (Thesis director) / Helms Tillery, Stephen (Committee member) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
137739-Thumbnail Image.png
Description
The role of retention and forgetting of context dependent sensorimotor memory of dexterous manipulation was explored. Human subjects manipulated a U-shaped object by switching the handle to be grasped (context) three times, and then came back two weeks later to lift the same object in the opposite context relative to

The role of retention and forgetting of context dependent sensorimotor memory of dexterous manipulation was explored. Human subjects manipulated a U-shaped object by switching the handle to be grasped (context) three times, and then came back two weeks later to lift the same object in the opposite context relative to that experience on the last block. On each context switch, an interference of the previous block of trials was found resulting in manipulation errors (object tilt). However, no significant re-learning was found two weeks later for the first block of trials (p = 0.826), indicating that the previously observed interference among contexts lasted a very short time. Interestingly, upon switching to the other context, sensorimotor memories again interfered with visually-based planning. This means that the memory of lifting in the first context somehow blocked the memory of lifting in the second context. In addition, the performance in the first trial two weeks later and the previous trial of the same context were not significantly different (p = 0.159). This means that subjects are able to retain long-term sensorimotor memories. Lastly, the last four trials in which subjects switched contexts were not significantly different from each other (p = 0.334). This means that the interference from sensorimotor memories of lifting in opposite contexts was weaker, thus eventually leading to the attainment of steady performance.
ContributorsGaw, Nathan Benjamin (Author) / Santello, Marco (Thesis director) / Helms Tillery, Stephen (Committee member) / Buneo, Christopher (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Harrington Bioengineering Program (Contributor)
Created2013-05
157696-Thumbnail Image.png
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 to proprioceptive error magnitude and direction. Efforts to improve focus and attention during upper limb proprioceptive tasks results in a

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.
ContributorsOrthlieb, Gerrit Chi Luk (Author) / Helms-Tillery, Stephen (Thesis advisor) / Tanner, Justin (Committee member) / Buneo, Christopher (Committee member) / Arizona State University (Publisher)
Created2019