Evaluation of Dexterous Terminal Device

Liberating Technologies, Inc. (LTI) has developed Pointdexter, a dexterous prosthetic fingertip that is integrated into a commercial prosthetic hand and allows for an additional fine grasp. The Pointdexter device interfaces with upper limb prostheses by swapping the usual prosthetic pointer finger with the Pointdexter device. The dexterous prosthetic fingertip utilizes the same control strategy used to operate the prosthetic hand. This solution aims to combine the advantages of the common terminal devices into one product by combining the practicality and dexterity of a split-hook or gripper with the aesthetics of multi-articulating hands.

The rationale for this study is to pilot test the dexterous prosthetic fingertip and gather user feedback. We will conduct in-lab testing to compare the functional outcomes of a commercial prosthetic hand with and without integration of the investigational dexterous fingertip prosthesis. A subset of subjects will take home the device for up to 2 weeks to test out the functionality in their daily lives and provide further feedback. This will be an exploratory pilot study with the intention of gaining a better understanding of device operation throughout activities of daily living (ADLs). User feedback will be collected to inform further development and design.

The study will focus on design feasibility testing and will compare performance of hand functional outcome tests on a commercially available prosthetic hand with and without the investigational Pointdexter modification. Our primary hypothesis is that subjects using the investigational device will show better performance on objective functional outcomes measures than those using a standard prosthetic hand, particularly in the manipulation of small objects.

The investigators will explore multiple outcomes measures as options, but our primary endpoint will be performance on the Small Common Objects subtask of the Jebsen-Taylor Hand Function Test, which assesses a broad range of unimanual hand functions required for ADLs. The primary quantitative measure of the Jebsen-Taylor task will be completion time of each subtask. Myoelectric prosthetic hand users will be recruited for the study and consented with an approved protocol. Able-bodied participants will be recruited for this study as long as they are willing to complete the approved protocol with an upper-limb prosthesis bypass.

There will be one site visit at LTI in Holliston, MA for in-lab functional outcome measure testing. The subject may be asked to return to the lab if testing and/or data collection is incomplete. At the start of the study session, subjects will prepare for testing in their first configuration (investigational or comparator). If investigational, subjects will doff their prosthesis and investigators will replace the usual index finger of the commercially available prosthetic hand being tested with the investigational device. If comparator, subjects will don the unmodified commercially available prosthetic hand. Subjects will be trained on how to operate the investigational device and be allowed a minimum of 30 minutes to practice using it until they are comfortable with proceeding. The subjects will be guided to conduct functional outcome tests that involve picking up and manipulating everyday objects (beans, coins, pegs, spoon, cloth, etc.), such as the tasks outlined in the Jebsen-Taylor and Peg Board functional tests. Each sub-task in the functional test will be scored by occupational therapist standards. After a round of functional testing is done, subjects will fill out a subjective questionnaire. Subjects will then doff the prosthesis and don the next device configuration. Subjects will repeat the functional tests and questionnaire with each device configuration. The study session should span about 4 hours.