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Scholarly Works (3 results)

  • Thesis
  • Peer Reviewed
UC Davis Electronic Theses and Dissertations (2024)

Despite significant mechatronic advancements in prosthetic hands, achieving the functionality of a biological extremity remains far from realized. For the development of next generation prosthetics and improved patient outcomes, standardized, reliable, and validated task-based evaluation measures are essential. A task-based approach, entailing the manipulation of physical objects with prostheses, directly assesses patient performance in real-time and offersnumerous benefits. Task-based assessments aid clinical decision-making, allowing clinicians to choose the best prosthetic device or strategy for individual patients and enables precise tracking of patient progress, highlighting treatment effectiveness or the need for adjustments. These measures also provide objective data for cost justification in insurance and public health systems, enhancing transparency among stakeholders, including researchers, clinicians, patients, and regulatory bodies. Finally, the standardization of task-based measures facilitates consistent comparisons across different prosthetic devices and control systems, promoting iterative improvement and innovation. Thus, properly implemented standardized evaluation measures are fundamental to the advancement of upper-limb prosthetics.

This thesis critically examines currently available task-based evaluation methods forupper-limb prosthetic technologies, highlighting the gap between the rapid advancement of prosthetic devices and the development of standardized assessment protocols. First, a comprehensive literature review, published in Frontiers in Robotics and AI, revealed that only 25 assessments for upper-limb prostheses have been validated since 1948, highlighting many researchers’ reliance on non-standardized tests that may not have rigorously established validity and not fully address the diverse interests of clinical and research communities. This research then applies theory to practice by using one of the highest rated currently available methods, the Anthropomorphic Hand Assessment Protocol (AHAP), to compare three open-source 3D-printed prosthetic hands with three commercially produced ones. This analysis, currently under review in BMC Biomedical Engineering, illustrates the practical challenges and advancements in prosthetic evaluation and paves the way for a more in-depth discussion on enhancing assessment methodologies. Finally, an online survey about task-based functional measures was conducted to understand and gather insights from diverse practitioners who interact with individuals prescribed upper-limb prostheses. The findings from this survey will influence future task-based evaluation methods and will be presented at the MyoElectric Control Conference in August 2024. This thesis not only provides insights into existing evaluation methods but also pinpoints areas for enhancement, significantly contributing to the development of effective and universally accepted evaluation techniques for upper-limb prostheses.

    Cover page: An Investigation into Validated Task-Based Evaluation Methods for Upper-Limb Prostheses
    • Article
    • Peer Reviewed
    UC Davis Previously Published Works (2023)
    This article provides a comprehensive narrative review of physical task-based assessments used to evaluate the multi-grasp dexterity and functional impact of varying control systems in pediatric and adult upper-limb prostheses. Our search returned 1,442 research articles from online databases, of which 25 tests-selected for their scientific rigor, evaluation metrics, and psychometric properties-met our review criteria. We observed that despite significant advancements in the mechatronics of upper-limb prostheses, these 25 assessments are the only validated evaluation methods that have emerged since the first measure in 1948. This not only underscores the lack of a consistently updated, standardized assessment protocol for new innovations, but also reveals an unsettling trend: as technology outpaces standardized evaluation measures, developers will often support their novel devices through custom, study-specific tests. These boutique assessments can potentially introduce bias and jeopardize validity. Furthermore, our analysis revealed that current validated evaluation methods often overlook the influence of competing interests on test success. Clinical settings and research laboratories differ in their time constraints, access to specialized equipment, and testing objectives, all of which significantly influence assessment selection and consistent use. Therefore, we propose a dual testing approach to address the varied demands of these distinct environments. Additionally, we found that almost all existing task-based assessments lack an integrated mechanism for collecting patient feedback, which we assert is essential for a holistic evaluation of upper-limb prostheses. Our review underscores the pressing need for a standardized evaluation protocol capable of objectively assessing the rapidly advancing prosthetic technologies across all testing domains.
      Cover page: Review and critique of current testing protocols for upper-limb prostheses: a call for standardization amidst rapid technological advancements.Creative Commons 'BY' version 4.0 license
      • Article
      • Peer Reviewed
      UC San Francisco Previously Published Works (2024)
      A single dose of psilocybin, a psychedelic that acutely causes distortions of space-time perception and ego dissolution, produces rapid and persistent therapeutic effects in human clinical trials1-4. In animal models, psilocybin induces neuroplasticity in cortex and hippocampus5-8. It remains unclear how human brain network changes relate to subjective and lasting effects of psychedelics. Here we tracked individual-specific brain changes with longitudinal precision functional mapping (roughly 18 magnetic resonance imaging visits per participant). Healthy adults were tracked before, during and for 3 weeks after high-dose psilocybin (25 mg) and methylphenidate (40 mg), and brought back for an additional psilocybin dose 6-12 months later. Psilocybin massively disrupted functional connectivity (FC) in cortex and subcortex, acutely causing more than threefold greater change than methylphenidate. These FC changes were driven by brain desynchronization across spatial scales (areal, global), which dissolved network distinctions by reducing correlations within and anticorrelations between networks. Psilocybin-driven FC changes were strongest in the default mode network, which is connected to the anterior hippocampus and is thought to create our sense of space, time and self. Individual differences in FC changes were strongly linked to the subjective psychedelic experience. Performing a perceptual task reduced psilocybin-driven FC changes. Psilocybin caused persistent decrease in FC between the anterior hippocampus and default mode network, lasting for weeks. Persistent reduction of hippocampal-default mode network connectivity may represent a neuroanatomical and mechanistic correlate of the proplasticity and therapeutic effects of psychedelics.
        Cover page: Psilocybin desynchronizes the human brainCreative Commons 'BY' version 4.0 license
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