Matching Items (147)
Description
This paper proposes a new socket design to complement Project Fishbone, a design project focused on creating a lightweight transradial prosthetic device. The socket has a simple concept of introducing perforations on the surface of the socket using cost effective, and rapid manufacturing methods such as vacuum thermoforming and drilling. The perforations on the socket allows for greater air ventilation to the prosthetic user's residual skin thus reducing the temperature within the socket. There were nine primary design iterations that were tested: 0.125, 0,187, 0.25-inch-thick designs, and 3/16, 15/64, 17/64-inch perforation sizes, and 12, 18 and 24 count of perforations. Initial test was done using the sockets of different thickness without any perforations to check for uniformity in design and manufacturing method using a regression test. It was found that an increase in thickness directly related to an increase in temperature cooling time. The temperature cooling test was run using a three-factor DOE method and no clear interaction between the factors was observed, thus the Kruskal-Wallis statistical test along with the post hoc Mann-Whitney test to check for significance among the factors as well as significance of groups within the factors. Statistical significance (p<0.05) was found in the socket thickness and size of perforations. Additionally, significance (p<0.02) was found in the 0.125 and 0.187-inch thickness and the 3/16-inch size perforations. Based on the significance between each group, the best combination for increased cooling time reduction was thus found to be with the 0.125-inch thick HDPE sheet and 3/16-inch sized perforation while the number of perforations did not make much difference. These results proved the concept of this new socket design that could be implemented into existing upper limb prosthetic systems.
ContributorsSebastian, Frederick (Author) / LaBelle, Jeffrey (Thesis director) / Lathers, Steven (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Startle-evoked-movement (SEM), the involuntary release of a planned movement via a startling stimulus, has gained significant attention recently for its ability to probe motor planning as well as enhance movement of the upper extremity following stroke. We recently showed that hand movements are susceptible to SEM. Interestingly, only coordinated movements of the hand (grasp) but not individuated movements of the finger (finger abduction) were susceptible. It was suggested that this resulted from different neural mechanisms involved in each task; however it is possible this was the result of task familiarity. The objective of this study was to evaluate a more familiar individuated finger movement, typing, to determine if this task was susceptible to SEM. We hypothesized that typing movements will be susceptible to SEM in all fingers. These results indicate that individuated movements of the fingers are susceptible to SEM when the task involves a more familiar task, since the electromyogram (EMG) latency is faster in SCM+ trials compared to SCM- trials. However, the middle finger does not show a difference in terms of the keystroke voltage signal, suggesting the middle finger is less susceptible to SEM. Given that SEM is thought to be mediated by the brainstem, specifically the reticulospinal tract, this suggest that the brainstem may play a role in movements of the distal limb when those movements are very familiar, and the independence of each finger might also have a significant on the effect of SEM. Further research includes understanding SEM in fingers in the stroke population. The implications of this research can impact the way upper extremity rehabilitation is delivered.
ContributorsQuezada Valladares, Maria Jose (Author) / Honeycutt, Claire (Thesis director) / Santello, Marco (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Research on human grasp typically involves the grasp of objects designed for the study of fingertip forces. Instrumented objects for such studies have often been designed for the simulation of functional tasks, such as feeding oneself, or for rigidity such that the objects do not deform when grasped. The goal of this thesis was to design a collapsible, instrumented object to study grasp of breakable objects. Such an object would enable experiments on human grip responses to unexpected finger-object events as well as anticipatory mechanisms once object fragility has been observed. The collapsible object was designed to be modular to allow for properties such as friction and breaking force to be altered. The instrumented object could be used to study both human and artificial grasp.
ContributorsTorrez, Troy (Author) / Santos, Veronica (Thesis director) / Santello, Marco (Committee member) / Artemiadis, Panagiotis (Committee member) / Barrett, The Honors College (Contributor)
Created2012-05
Description
Telestroke networks reduce disparities in acute stroke care between metropolitan primary stroke centers and remote hospitals. Current technologies used to conduct remote patient assessments have very high start-up costs, yet they cannot consistently establish quality connection in a timely manner. Smartphgones can be used for high quality video teleconferencing (HQ-VTC). They are relatively inexpensive and widley used among healthcare providers. We aimed to study the reliability of HQ-VTC using smartphones for conducting the NIHSS. Two vascular neurologists (VNs) assessed 83 stroke patients with the NIHSS. The remote VN assessed patients using videoconferencing on a smartphone with the assistance of a bedside medical aide. The bedside VN rated patients ontemporaneously. Each VN was blinded to the other's NIHSS scores. We tested the inter-method agreement and physician satisfaction with the device. We demonstrated high total NIHSS score correlation between the methods (r=0.941, p<0.001). The mean total NIHSS scores for bedside and remote assessments were 7.3 plus or minus 7.9 and 6.7 plus or minus 7.6 with ranges of 0-30 and 0-37, respectively. Seven NIHSS categories had significantly high agreement beyond chance: LOC-questions, LOC-commands, visual fields, motor left arm, motor right arm, motor left leg, motor right leg; seven categories had moderate agreement: LOC-consciousness, best gaze, facial palsy, sensory, best language, dysarthria, extinction/inattention; one category had poor agreement: ataxia. There was high physician satisfaction with the device. The VNs rated 96% of the assessments as good or very good for "image quality," "sound quality," "ease of use," and "ability to assess subject using NIHSS," and 84% of the assesssments as good or very good for "reception in hospital." The smartphones with HQ-VTC is reliable, easy to use, and affordable for telestroke NIHSS administration. This device has high physician satisfaction. With the variety of smartphones and professional medical applications available today, the telestroke practitioner has all the tools necessary for fast clinical decision-makingby accessing electronic medial records, viewing images, and tracking patient vitals.
ContributorsVegunta, Sravanthi (Author) / Demaerschalk, Bart (Thesis director) / Santello, Marco (Committee member) / Hurlbut, Ben (Committee member) / Barrett, The Honors College (Contributor)
Created2012-05
Description
The purpose of this paper was to systematically review current literature regarding the effect of hand splints on aesthetic outcomes for individuals with acquired hand deformities. Hand splints vary in form and function, and are used to maintain or ameliorate hand function and aesthetics. A literature search was performed on peer-reviewed publications that used splinting as an intervention for conservative hand improvement. Evidence from ten randomized clinical trials (published from 2003 to 2015) was evaluated for aesthetic improvement among a total of 659 subjects. Cosmetic outcomes were analyzed by a change in angle measurements, such as extensor lag, ulnar deviation, and passive and active range of motion. Of these ten studies, five focused on hand deformities caused by neurological impairment, while the other five measured those with musculoskeletal complications. Only two of the ten studies concluded that splinting could aesthetically improve the hands, and only one of these reporting statistical significance in its data. The data was not only limited in quantity, but was presented in heterogeneous formats. There was an extensive variation in measured outcomes, intervention protocols, follow-up times, and many other aspects of the studies; this dissimilarity led to difficulty in performing a systematic assessment. The majority of evidence concludes that splinting does not improve the appearance of deformities, however none directly investigated this measure. Therefore, further RCTs that include measurements of cosmetic traits are necessary to better quantify the effect of splinting for management of hand deformities. This review was the first of its kind to evaluate the correction of hand deformities using splints as an intervention.
ContributorsVale, Nicholas Marshall (Author) / Santello, Marco (Thesis director) / Skiba, Jeffry (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor, Contributor) / School of Biological and Health Systems Engineering (Contributor)
Created2017-05
Description
Interdigitated back contact (IBC) solar cells have achieved the highest single junction silicon wafer-based solar cell power conversion efficiencies reported to date. This thesis is about the fabrication of a high-efficiency silicon heterojunction IBC solar cell for potential use as the bottom cell for a 3-terminal lattice-matched dilute-nitride Ga (In)NP(As)/Si monolithic tandem solar cell. An effective fabrication process has been developed and the process challenges related to open circuit voltage (Voc), series resistance (Rs), and fill factor (FF) are experimentally analyzed. While wet etching, the sample lost the initial passivation, and by changing the etchant solution and passivation process, the voltage at maximum power recovered to an initial value of over 710 mV before metallization. The factors reducing the series resistance loss in IBC cells were also studied. One of these factors was the Indium Tin Oxide (ITO) sputtering parameters, which impact the conductivity of the ITO layer and transport across the a-Si:H/ITO interface. For the standard recipe, the chamber pressure was 3.5 mTorr with no oxygen partial pressure, and the thickness of the ITO layer in contact with the a-Si:H layers, was optimized to 150 nm. The patterning method for the metal contacts and final annealing also change the contact resistance of the base and emitter stack layers. The final annealing step is necessary to recover the sputtering damage; however, the higher the annealing time the higher the final IBC series resistance. The best efficiency achieved was 19.3% (Jsc = 37 mA/cm2, Voc = 691 mV, FF = 71.7%) on 200 µm thick 1-15 Ω-cm n-type CZ C-Si with a designated area of 4 cm2.
ContributorsMoeini Rizi, Mansoure (Author) / Goodnick, Stephen (Thesis advisor) / Honsberg, Christina (Committee member) / Goryll, Michael (Committee member) / Smith, David (Committee member) / Bowden, Stuart (Committee member) / Arizona State University (Publisher)
Created2022
Description
The future will be replete with Artificial Intelligence (AI) based agents closely collaborating with humans. Although it is challenging to construct such systems for real-world conditions, the Intelligent Tutoring System (ITS) community has proposed several techniques to work closely with students. However, there is a need to extend these systems outside the controlled environment of the classroom. More recently, Human-Aware Planning (HAP) community has developed generalized AI techniques for collaborating with humans and providing personalized support or guidance to the collaborators. In this thesis, the take learning from the ITS community is extend to construct such human-aware systems for real-world domains and evaluate them with real stakeholders. First, the applicability of HAP to ITS is demonstrated, by modeling the behavior in a classroom and a state-of-the-art tutoring system called Dragoon. Then these techniques are extended to provide decision support to a human teammate and evaluate the effectiveness of the framework through ablation studies to support students in constructing their plan of study (\ipos). The results show that these techniques are helpful and can support users in their tasks. In the third section of the thesis, an ITS scenario of asking questions (or problems) in active environments is modeled by constructing questions to elicit a human teammate's model of understanding. The framework is evaluated through a user study, where the results show that the queries can be used for eliciting the human teammate's mental model.
ContributorsGrover, Sachin (Author) / Kambhampati, Subbarao (Thesis advisor) / Smith, David (Committee member) / Srivastava, Sidhharth (Committee member) / VanLehn, Kurt (Committee member) / Arizona State University (Publisher)
Created2022
Description
Written corrective feedback (WCF) has received considerable attention in secondlanguage (L2) writing research. The conducive role of WCF in developing L2 writing and
second language acquisition has been corroborated by a number of theoretical frameworks,
and the findings of empirical studies, meta-analyses, and research syntheses. WCF research
has predominantly addressed its effectiveness in improving learners’ syntactic, lexical, and
orthographic knowledge. This dissertation project extends the scope of this line of research
to formulaic aspects of language and investigates the relative effectiveness of WCF
targeting formulaic vs. non-formulaic constructions in L2 writing. The text-analytic
descriptive aspect of this research design aimed at investigating the extent of L2 learners’
non-target-like use of formulaic vs. non-formulaic forms in L2 writing and writing
teachers’ WCF treatment of non-target (non)formulaic language use. A total of 480 first
drafts of essays written by 33 advanced adult English-as-a-foreign language (EFL) learners
during one semester and 480 drafts of essays corrected through WCF by three EFL teachers
constituted the corpus in this study. Advancing the field of learner corpus research, the
findings demonstrated that whereas learners’ non-target formulaic forms outnumbered that
of non-formulaic ones in their writing assignments, all three teachers provided WCF more
often for erroneous use of non-formulaic forms. The quasi-experimental aspect of the
research design attempts to add new empirical evidence on the L2 learning potential of
accessing and processing WCF provided for formulaic vs. non-formulaic constructions in
L2 writing. To this end, a total of 66 EFL learners in a Test of English as a Foreign
Language preparation course participated in a pretest-posttest design, with 5 experimental groups (those who were provided with direct, indirect, direct plus metalinguistic, and
indirect plus metalinguistic WCF) and a control group (those who were not provided with
WCF). Maintaining a division between formulaic vs. non-formulaic forms, the findings
provide empirical evidence on the interactions between types of WCF, types of linguistic
targets, and the effectiveness of WCF in terms of enhancing L2 learners’ accuracy and
acquisition in their revised writing and new writings in the short and long term.
ContributorsGholami, Leila (Author) / Smith, David (Thesis advisor) / Matsuda, Paul K (Committee member) / James, Mark A (Committee member) / Arizona State University (Publisher)
Created2022
Description
Although previous studies have elucidated the role of position feedback in the regulation of movement, the specific contribution of Golgi tendon organs (GTO) in force feedback, especially in stabilizing voluntary limb movements, has remained theoretical due to limitations in experimental techniques. This study aims to establish force feedback regulation mediated by GTO afferent signals in two phases. The first phase of this study consisted of simulations using a neuromusculoskeletal model of the monoarticular elbow flexor (MEF) muscle group, assess the impact of force feedback in maintaining steady state interaction forces against variable environmental stiffness. Three models were trained to accurately reach an interaction force of 40N, 50N and 60N respectively, using a fixed stiffness level. Next, the environment stiffness was switched between untrained levels for open loop (OL) and closed loop (CL) variants of the same model. Results showed that compared to OL, CL showed decreased force deviations by 10.43%, 12.11% and 13.02% for each of the models. Most importantly, it is also observed that in the absence of force feedback, environment stiffness is found to have an effect on the interaction force. In the second phase, human subjects were engaged in experiments utilizing an instrumented elbow exoskeleton that applied loads to the MEF muscle group, closely mimicking the simulation conditions. The experiments consisted of reference, blind and catch trial types, and 3 stiffness levels. Subjects were first trained to reach for a predetermined target force. During catch trials, stiffness levels were randomized between reaches. Responses obtained from these experiments showed that subjects were able to regulate forces with no significant effects of trial type or stiffness level. Since experimental results align closely with that of closed loop model simulations, the presence of force feedback mechanisms mediated by GTO within the human neuromuscular system is established. This study not only unveils the critical involvement of GTO in force feedback but also emphasizes the importance of understanding these mechanisms for developing advanced neuroprosthetics and rehabilitation strategies, shedding light on the intricate interplay between sensory inputs and motor responses in human proprioception.
ContributorsAbishek, Kevin (Author) / Lee, Hyunglae (Thesis advisor) / Buneo, Christopher (Committee member) / Santello, Marco (Committee member) / Arizona State University (Publisher)
Created2023
Description
A current thrust in neurorehabilitation research involves exogenous neuromodulation of peripheral nerves to enhance neuroplasticity and maximize recovery of function. This dissertation presents the results of four experiments aimed at assessing the effects of trigeminal nerve stimulation (TNS) and occipital nerve stimulation (ONS) on motor learning, which was behaviorally characterized using an upper extremity visuomotor adaptation paradigm. In Aim 1a, the effects of offline TNS using clinically tested frequencies (120 and 60 Hz) were characterized. Sixty-three participants (22.75±4.6 y/o), performed a visuomotor rotation task and received TNS before encountering rotation of hand visual feedback. In Aim 1b, TNS at 3 kHz, which has been shown to be more tolerable at higher current intensities, was evaluated in 42 additional subjects (23.4±4.6 y/o). Results indicated that 3 kHz stimulation accelerated learning while 60 Hz stimulation slowed learning, suggesting a frequency-dependent effect on learning. In Aim 2, the effect of online TNS using 120 and 60 Hz were characterized to determine if this protocol would deliver better outcomes. Sixty-three participants (23.2±3.9 y/o) received either TNS or sham concurrently with perturbed visual feedback. Results showed no significant differences among groups. However, a cross-study comparison of results obtained with 60 Hz offline TNS showed a statistically significant improvement in learning rates with online stimulation relative to offline, suggesting a timing-dependent effect on learning. In Aim 3, TNS and ONS were compared using the best protocol from previous aims (offline 3 kHz). Additionally, concurrent stimulation of both nerves was explored to look for potential synergistic effects. Eighty-four participants (22.9±3.2 y/o) were assigned to one of four groups: TNS, ONS, TNS+ONS, and sham. Visual inspection of learning curves revealed that the ONS group demonstrated the fastest learning among groups. However, statistical analyses did not confirm this observation. In addition, the TNS+ONS group appeared to learn faster than the sham and TNS groups but slower than the ONS only group, suggesting no synergistic effects using this protocol, as initially hypothesized.
The results provide new information on the potential use of TNS and ONS in neurorehabilitation and performance enhancement in the motor domain.
ContributorsArias, Diego (Author) / Buneo, Christopher (Thesis advisor) / Schaefer, Sydney (Committee member) / Helms-Tillery, Stephen (Committee member) / Santello, Marco (Committee member) / Kleim, Jeffrey (Committee member) / Arizona State University (Publisher)
Created2023