Session: 15-01-01: ASME International Undergraduate Research and Design Exposition

Paper Number: 149563

149563 - Assistive Dorsal Grasper Modifications for In-Home Experiment 

Individuals with spinal cord injury (SCI) frequently encounter limitations in their typical manual capabilities and cannot perform many dexterous manipulations independently. The Dorsal Grasper, an assistive wearable grasping device introduced in the prior study, augments the user with two supernumerary fingers and an artificial palm to enable grasping with the back of the hand. Specifically designed for individuals with C6/C7 spinal cord injuries, the device leverages the residual active wrist extension that often remains in this population after injury, despite the loss of voluntary finger flexion. The device allows the users to actively participate in applying grasping forces on objects, ideally enabling intuitive, fast and reliable grasping relevant for the execution of activities of daily living. Functional grasping was tested with three normative subjects and a person with C6 SCI using the Grasp, Carry, and Release Test. Previous study concluded that the design supports intuitive and fast grasping relevant for daily activities but tested performance in a controlled laboratory setting. Thus, future work must test whether this intervention has efficacy in a realistic home environment. 

In this presentation, we introduce several improved elements and a modified design to reduce weight, increase grasp force, and include the ability to don and doff the device independently. The modifications to the device represent significant advancements aimed at addressing practical concerns voiced by users. By reducing weight and increasing grasp force, we anticipate a more comfortable and effective user experience. Previously anchored to the arm with wristbands, the new design considers the hand and wrist bone structure and simplifies the adjustability of the device for patient use using personalize metal bands attached to the wrist and the arm. These improvements not only enhance the device's functionality but also contribute to the user's sense of autonomy and confidence in daily activities.

I will also discuss the study design for testing natural behaviors in the home, and how we will instruct subjects to collect egocentric video so that we can perform a taxonomic classification of different grasp types used during day-to-day utilization. This approach aims to capture natural behaviors and challenges encountered during typical daily routines, providing valuable insights into the device's effectiveness and usability in diverse contexts.

The new device can enhance patients’ independence through a low-cost assistive grasping driven by electric power that does not impede natural grasping function. We conducted a case study of a person with C6 SCI using the new Dorsal Grasper to perform the grasping, transportation, and refilling of a water cup. Results indicate that improvements to the design support user performance on a subset of objects that complement existing compensatory strategies.

Presenting Author: Alahe Akhavan University of California, Berkeley

Presenting Author Biography: Alahe Akhavan was born in Herat, Afghanistan. From an early age, she was part of the Afghan girls robotics team. After moving to the United States as a teenager, she continued her interest by getting involved in her high school’s robotics team. During college, as a Mechanical Engineering major she gained a passion for research. Some of her research contributions include Multi-Robotic Motion and Control planning, Tactile Sensing Control, and Assistive Grasping Design and testing. She currently is on the path of completing her undergraduate degree in University of California Berkeley in Mechanical Engineering and minor in computer science. Her future goals are to complete her masters and graduate degree in Mechanical Engineering with a focus on medical devices.

Authors:

Alahe Akhavan University of California, Berkeley
Drew Mcpherson University of California, Berkeley
Jungpyo Lee University of California, Berkeley
Hannah Stuart University of California, UC Berkeley