Background: This is a renewal application for the RR&D funded Merit Review titled, Home Study of an Advanced Upper Limb Prosthesis (Home Study). The DEKA Arm is designed to use inertial measurement units (IMUs) worn on the feet in combination with traditional EMG controls and switches, as needed to control multiple degrees of freedom. To date, one or more IMUs were required to operate the device. There is substantial cognitive load required for the complex task of pre-planning and sequentially controlling multiple joints/actuators using this control method. Recent commercial release of an EMG pattern recognition system holds promise for decreasing cognitive burden by eliminating the IMUs. Substituting foot control with more intuitive pattern recognition control may lead to greater acceptance of and better function with the DEKA Arm. Purpose: The overall objective is to examine the feasibility, acceptance and benefits of home use of the DEKA Arm, as well as the logistical support requirements utilized during 3 months of home usage. Specifically we aim to: 1) Identify and describe upper limb amputees who would be appropriate candidates for home use of this advanced prosthesis as well as those who would not be appropriate; 2) Compare the extent of use of the existing prosthesis to that of the DEKA Arm and quantify the impact of home use of the DEKA Arm on device satisfaction, performance of functional activities and the user's quality of life; 3) Compare the outcomes of users of pattern recognition to the outcomes of users without; and 4) Quantify the amount and type of technical support and repairs needed during the study, and estimate the number of home study days lost due to service/repair. Methods: Design. The study uses a quasi-experimental, time series design. This study has 2 parts: Part A involves in-laboratory training and supervised community outings using the DEKA Arm; Part B involves a 3 month trial of home use. Sample. This renewal will recruit up to 12 additional subjects with transradial or transhumeral amputation. Procedures. Part A subjects will maintain daily logs of prosthesis use prior to training. Subjects will be fit with a prosthetic socket, have EMG pattern recognition controls configured, and then be trained to use the DEKA Arm. After training, the study staff will classify each participant as appropriate or not appropriate for home usage. For Part B, we will gather data on home safety, prosthetic use and technical support required during the home trial. We will use standardized outcome measures collected in Part A and B to examine outcomes of pain, dexterity, functional activities, prosthetic satisfaction and quality of life and collect qualitative data from home safety assessments, video logs, surveys, interviews and prosthetic usage journals. Data Analysis. We will calculate the percentage of subjects who participate in Part A of the study who are determined to have met the preliminary criteria for home use appropriateness. We will describe subjects in each group and examine characteristics of those subjects who were not considered appropriate candidates for home use to identify which, if any factors were predictive. Measures of existing prosthetic activity will be compared with those of home use of the DEKA Arm to determine the extent of adoption. We will examine changes in device satisfaction, performance of functional activities and quality of life throughout the study using within subject pre and post intervention measures. We will summarize descriptive data on technical support usage. We will compare outcomes for subjects using pattern recognition control to outcomes for subjects at similar configuration levels who did not use pattern recognition using nonparametric Wilcoxon- Mann-Whitney tests. Importance: Results will inform the adoption of pattern recognition controls and help to move the DEKA Arm closer to successful deployment. Results will provide important information to help determine which amputees are appropriate candidates for the DEKA Arm, as well as provide data on usefulness and acceptability in a home environment. Findings will help inform the development of clinical guidelines for prescription of advanced upper limb prosthetic technology and controls.