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The DEKA Arm System consists of a prosthetic arm and accessories, which are used by a certified prosthetist to create a full upper extremity prosthesis indicated for individuals, age 18 years and older, who have partial or full upper limb amputations or congenital defects. The device is used to assist in activities of daily living (ADLs).

The DEKA Arm System is a lithium-ion battery operated upper limb prosthesis intended to restore limb functions in individuals who lost all (i.e., shoulder disarticulations) or part of either upper limb (e.g., trans-radial amputation). Three configurations may exist, depending on the level of amputation or congenital defect: shoulder configuration (SC), humeral configuration (HC), and radial configuration (RC). It can provide up to 10 active degrees of freedom. Main components consist of Mechanical limb hardware, Arm Control Interfaces (ACI) that record user input signals (myoelectric recording electrodes, discrete bump switches, linear transducers, Inertial Measurement Units (IMUs), and force sensing resistors), Inertial Measurement Units (IMU) that record arm and foot movements, Master Arm Controller (MAC) that is the main processor, Arm Control Modules (ACM)/Hand Control Module (HCM) that control movement and are used for each respective limb component, and One or more battery modules and holsters. These components communicate via the Controller Area Network (CAN). The device is powered through a separate power bus. The system, not including the IMUs, is IP52 rated. The MAC controls wrist movement only, but oversees all actuators. There is afferent and efferent communication between the MAC and ACMs, HCM, IMUs, ACIs and battery module. The ACMs control actuators above the wrist while the HCM controls actuators below the wrist. The battery module may be embedded inside the arm, or worn outside the arm. IMUs do have a Power Control Module for the battery and are IP57 liquid/particle ingress rated. The hand has a grip release button that will release the grip in emergencies. The arm communicates wirelessly via 2 RF channels to a personal computer (PC) for configuration, as well as up to two IMUs. Signal acquisition from the user may be derived from cutaneous myoelectric recording electrodes, discrete bump switches, linear transducers, IMUs, and force sensing resistors, with the ability to accommodate 4 inputs (including up to 2 wireless inputs). Each of the 4 input methods may use up to 4 channels each. Wireless input comes only from the IMUs. Wired input is acquired through the ACIs and transmitted to the MAC. Modes are used to control the 10 degrees of freedom, including Standby, Hand, and Arm modes. Feedback will be provided by a tactor and an LED control display on the arm.

Here's a breakdown of the acceptance criteria and the study information for the DEKA Arm System, based on the provided text:

Acceptance Criteria and Reported Device Performance

The acceptance criteria are derived from the "SPECIAL CONTROLS" section and the "Basic Safety and Essential Performance" section within the Electrical Testing. The reported device performance is gathered from the "SUMMARY OF NONCLINICAL/BENCH STUDIES" and "SUMMARY OF CLINICAL INFORMATION" sections.

Table of Acceptance Criteria and Reported Device Performance:

• Leakage current tests within specification.
• During operation, a failure in communication between control modules shall result in the prosthesis reverting to a safe state.
• During operation, a detectable failure or out of range reading of any sensor or motor shall result in the prosthesis reverting to a safe state.
• When power is removed, system shall revert to a safe state.
• Means to turn power on/off. | - Leakage current tests (IEC 60601-1: Sec. 8.7) were within specification and acceptable.
• EMC testing performed to IEC 60601-1-2 and additional FDA RF Wireless Guidance, all tests passed for various configurations.
• Software/firmware review (Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices, 2005) determined moderate level of concern.
• Wireless communications with PC are checksummed to maintain safety.
• Fault Safety: During fault/shutdown, arm slows/stops, hand stops; sensory input ignored (except hand open button).
• Sudden power loss testing ensured defined safe state is reached.
• Arm is limited in joint speed and further reduced when moving towards face.
• Hand has a grip release button (two for redundancy) that releases grip in emergencies.
• System provides ON/OFF switches (soft Off 1-2s, hard Off 8s). |
  | Software Performance | - Appropriate software verification, validation, and hazard analysis must be performed. | - All software (Luke Arm Software, Prosthetist Interface (PI) Software) was appropriately validated.
• PI Software allows configuration of arm movements in response to EMG/other inputs, with a virtual reality environment for testing. |
  | Non-clinical Performance | - Non-clinical performance data must demonstrate that the device performs as intended under anticipated conditions of use.
• Mechanical bench data, including durability testing, to demonstrate that the device will withstand forces, conditions, and environments encountered during use.
• Simulated use testing to demonstrate performance of arm commands and safeguard(s) under worst-case conditions and after durability testing.
• Verification and validation of force sensors and hand release button.
• Device functionality in terms of flame retardant materials, liquid/particle ingress prevention, sensor/actuator performance, motor/brake performance.
• Accuracy of device features and safeguards. | - Durability testing (2 samples, simulated 3 years of usage by cycling arm 4,000-28,000 times) found some components required maintenance after 18 months, leading to updated labeling. Tests were acceptable, criteria met.
• Mechanical strength testing (IEC 60601-1:2005 Sec. 15.3) conducted.
• IP52 testing documented (IMU is IP57 rated) in accordance with IEC 60529.
• Testing of face approach velocity slowdown done (from various initial positions).
• ACI and IMU communication loss testing performed.
• Hand open button tested with different grips.
• Device reverts to safe state if joint is overloaded (prevents whipping).
• Can carry payload of up to 3.9 kg.
• Biocompatibility evaluation of patient-contacting materials performed (electrodes cleared in K032833; socket materials tested per ISO 10993). Materials well-characterized.
• Abuse testing (shock and impact) done per IEC 60601-1-11 2010 and IEC 60601-1:2005 Sec. 15.3.
• Device passed all identified non-clinical tests. |
  | Clinical Performance | - Non-clinical and clinical performance testing must demonstrate the accuracy of device features and safeguards.
• Documented clinical experience and human factors testing must demonstrate safe and effective use, capture any adverse events observed during clinical use and demonstrate the accuracy of device features and safeguards. | VA Study (Study 1):
• Evaluated usability, dexterity, prosthetic skill, spontaneity, daily activities, and satisfaction.
• 29 subjects completed objective testing.
• Comparison of DEKA Arm (Gen3) vs. current prosthesis showed DEKA Arm outperformed current prosthesis in most activities (Figure 3), and was preferred by 83% of users (Table 2).
• Two of four self-report measures (UEFS Use, Patient Specific Functional Scale) were significantly better with the DEKA Arm.
• 77% of participants wanted a DEKA Arm in the future.
  DEKA Study (Study 2):
• 10 arm users.
• Participants found Gen2 and Gen3 comfortable, wore them 7 hrs/day and 6 hrs/day respectively.
• Reported DEKA Arm was better at performing tasks than existing prosthesis.
• Reliability reported as fair, improving to near excellent for later Gen3 subjects.
• Feedback from heavy users led to design changes.
  Overall: Studies "reasonably demonstrate the safety and effectiveness of the DEKA arm system during the completion of predefined tasks and spontaneous activities in both the laboratory and home settings." |
  | Biocompatibility | - Elements of the device that may contact the patient must be demonstrated to be biocompatible. | - Electrodes previously cleared (K032833) and passed biocompatibility testing.
• Socket materials (prolonged contact) tested per ISO 10993 for skin irritation, sensitization, and cytotoxicity.
• Materials well characterized in prosthetic applications. |
  | Labeling | - Labeling for Prosthetist and User Guide must include:
  a. appropriate instructions, warnings, cautions, limitations, info on safeguards (e.g., driving).
  b. specific instructions and clinical training (assembling, fitting, programming, controls, modes, safety features, maintenance).
  c. information on patient population for which device effective.
  d. detailed summary of non-clinical and clinical testing. | - Patient labeling written according to "Guidance on Medical Device Patient Labeling" (2001), readable and understandable.
• Definitions of symbols described.
• Labeling checked according to IEC 60601-1:2005 Clause 7.
• Indications for Use in User and Prosthetist guides.
• Contraindications in Prosthetists Guide are general and appropriate.
• User/Prosthetist Guides provide clear and understandable instructions, warnings, cautions.
• Contact info provided for electrode replacement.
• Labeling updated for maintenance needs based on durability testing. |

Study Details:

2. Sample Size Used for the Test Set and Data Provenance

• Study 1 (VA Study):
  • Test Set Sample Size: 36 arm users enrolled, 29 completed all objective testing.
  • Data Provenance: Retrospective and prospective. The study was described as an "iterative usability and optimization study with repeated measures collected prior to and after users received the DEKA Arm." It was conducted in the US (Veterans Affairs).
• Study 2 (DEKA Study):
  • Test Set Sample Size: 10 arm users.
  • Data Provenance: Retrospective and prospective. The study involved daily interviews during a home use portion (two-week interval), suggesting a prospective data collection approach. Conducted by the sponsor, likely in the US.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

The studies primarily used a mixed-methodology approach involving performance-based tests (objective measures) and self-report measures (subjective from users). There isn't an explicit mention of a panel of independent experts establishing a "ground truth" in the sense of diagnostic imaging (e.g., radiologists interpreting images). Instead, the "ground truth" for performance was based on:

• Clinical Assessments: Administered by study personnel/therapists using standardized tests (e.g., Modified Box and Blocks Test, Jebsen-Taylor Hand Function Test). These individuals would be qualified in rehabilitation and prosthetics.
• Prosthetist Ratings: Evaluations of ease of fitting and setup.
• Therapist Ratings: Evaluations of ease of training and aspects of the arm's function.
• User Reports: Self-reported ease of use, satisfaction, and ability to perform tasks.

The number and specific qualifications (e.g., years of experience) of the prosthetists, therapists, or other clinical personnel involved in administering these tests or providing ratings are not specified in the provided text.

4. Adjudication Method for the Test Set

The text does not explicitly describe an adjudication method (like 2+1 or 3+1 consensus) for the test set. For performance-based tests, scores are derived from direct observation or timed tasks. For self-report measures, user responses are directly collected. The study design does not suggest a need for "adjudication" in the typical sense of resolving conflicting expert opinions on a specific diagnosis or finding.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done

• Yes, a comparative effectiveness study was done, comparing the DEKA Arm to the subjects' existing prostheses. However, it was not an MRMC study in the traditional sense of multiple "readers" (e.g., radiologists) evaluating cases.
• Effect Size of Human Readers Improvement with AI vs. Without AI Assistance: This specific metric (human reader improvement with/without AI assistance) is not applicable here as the DEKA Arm is a prosthetic device for physical function, not an AI diagnostic tool primarily assisting human interpretation.
  • Instead, the studies compared the human user's performance with the DEKA Arm to their performance with their existing prosthesis.
  • Study 1 (VA Study) results:
    • The DEKA Arm (Gen3) outperformed current prostheses in most activities (Figure 3, where DEKA Arm, black bars, are generally longer).
    • 83% of users preferred the DEKA Arm for specific activities (Table 2).
    • Two of four self-report measures were significantly better with the DEKA Arm.
    • Performance was significantly slower on 2 measures (Box and Block and Jebsen feeding tests) with the DEKA Arm.
  • Study 2 (DEKA Study) results: Participants reported the arm system was better at performing tasks than their existing prosthesis.

6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done

This question is not applicable to the DEKA Arm System. The DEKA Arm is a prosthetic device designed for human use and controlled directly by the user. It does not operate as a standalone algorithm or AI model in a diagnostic or interpretive capacity. Its "performance" is inherently human-in-the-loop. The non-clinical bench testing does evaluate the device's technical functions independently, but this is not a standalone "algorithm" performance test.

7. The Type of Ground Truth Used

The "ground truth" was established through a combination of:

• Performance-based tests: Objective measures of dexterity and functional activities (e.g., number of blocks moved, tasks completed in time, observation of successful completion).
• Self-report measures: Subjective assessment of satisfaction, ease of use, and perceived difficulty from the users themselves.
• Professional ratings: Evaluations by prosthetists and therapists.

This is a clinical "ground truth" based on observed functional performance and user experience, rather than a pathological or outcomes-based "ground truth" derived from a definitive diagnostic test.

8. The Sample Size for the Training Set

The provided document describes clinical studies and non-clinical/bench studies. There is no explicit mention of a "training set" in the context of machine learning model development for the DEKA Arm System's operation or evaluation. The studies focus on testing the finished device.

The development process for the DEKA Arm involved iterative design based on feedback, especially from the Gen2 to Gen3 versions ("changes listed above are improvements made based on feedback received during device testing"). This feedback loop could be considered a form of "training" or refinement for the device design, but not a "training set" for a separate AI model within the device in the sense of deep learning.

9. How the Ground Truth for the Training Set Was Established

As there is no distinct "training set" for a machine learning model identified in the document, this question is not applicable. The "ground truth" for the device's development was likely established through engineering specifications, user requirements, and iterative testing and feedback during the design phases.

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