PROJECT SUMMARY
The human hand plays a critical role in performing many daily activities including self-feeding, tool use, and
recreation. Therefore, loss of the hand due to traumatic injury or disease can significantly limit or interfere with
the ability of persons with limb loss to perform daily activities and work, thus greatly affecting overall quality of
life. Despite advances in prosthetic hand design and research, several barriers to widespread acceptance of
prosthetic hands by persons with upper limb loss remain, including limited ability to perform daily activities and
poor durability of the prosthetic hand. Therefore, today’s commercially-available myoelectric hand prostheses
fail to address the needs of persons with limb loss, i.e., regaining some degree of autonomy, functionality, and
re-entry into the work force. To address these gaps, in the past few years we have investigated the extent to
which an artificial anthropomorphic hand originally designed for robotic grasping and manipulation – the
SoftHand – could be used for prosthetic applications through a non-invasive myoelectric controller – the
SoftHand Pro (SHP). The novel design of the SHP is the only prosthetic hand in the world that combines the
concept of human hand synergies and soft robotics technologies. The results of preliminary functional
assessments and biomechanical analyses revealed that individuals with upper limb loss could perform a
variety of grasping and manipulation tasks with the SHP at levels similar or superior to those of their preferred
prosthetic device. Additionally, subject surveys reported positive feedback about the ease and comfort
associated with using the SHP. This feedback was also instrumental in making software and hardware
improvements to make the hand lighter and able to grasp and manipulate small objects. We propose to
determine the extent to which the SHP can address three critical needs of transradial amputees that are not
met by commercially-available hand prostheses: function, versatility, and robustness. We will attain this
objective by comparing its function, versatility, and robustness with a commercially-available multi-digit
prosthetic hand, the i-limb (Ossur). We will pursue three aims: (1) to determine the extent to which
performance of grasping and manipulation tasks using the SHP is superior to the i-limb, (2) to determine the
extent to which daily use of the SHP and i-limb over an extended period of time improves grasping and
manipulation performance, and (3) to obtain SHP usage patterns and subjects’ satisfaction ratings from using
the SHP and i-limb. We will test the hypotheses that (1) the SHP will outperform the i-limb, and (2) daily use of
both prosthetic hands over an 8-week period each will lead to significantly greater improvement in grasping
and manipulation performance with the SHP than the i-limb. We will obtain usage and survey data collected
through the SHP and i-limb firmware during daily use to complement data obtained in Aims 1 and 2 to explore
daily use. This proposed work is significant because it will shed insight on whether an innovative soft synergy-
based prosthetic design allows for function, versatility and robustness not available in commercial prostheses.
