Long-Term Functional Improvement with Dexterous Prosthetic Limb

Abstract

Advanced myoelectric prosthetic devices aim to restore functional capability after upper limb loss. However, studies of their functional impact have been mostly limited to short-term clinical studies which rely on assessments of simple manual tasks. Here we show that a longer term study can elucidate functional improvement and quantify how and when a prosthesis is used. A participant with transhumeral amputation and an osseo-integrated interface participated first in a ten-day study of functional capability with a highly prosthesis, the Modular Prosthetic Limb (MPL). A few months later, he took the MPL home and used it daily for 12 months. He returned to the laboratory for functional assessments every two months. We measured improved scores in Assessment of Capability with Myoelectric Control, Box and Blocks Test, and NASA Task Load Index over the course of the long-term phase. Only slight improvement was documented over the short-term clinic-based phase, which suggests that longer studies may be required to assess capability with highly dexterous prosthetic limbs. Additionally, the loads experienced by the limb in the home environment were much greater than during the laboratory visits, which suggests that the functional assessments do not capture the full spectrum of loads placed on a prosthesis during activities of daily living. Through the combination of functional outcome measures, on-board data logging, and long-term studies in the home environment, we are developing the capability to assess upper limb rehabilitation progress and device appropriateness.