(50 days)
The Handmaster is intended to be used for the following indications: maintenance or increase of range of motion, reduction of muscle spasm, prevention or retardation of disuse atrophy, muscle reeducation, and increasing local blood circulation. In patients suffering from upper limb paralysis due to C5 spinal cord injury or hemiplegic patients due to stroke, it is also intended to provide hand active range of motion and hand function.
The Handmaster is a portable, one-channel electrical neuromuscular stimulator for personal use. The stimulator serves five surface electrodes held on to the upper limb by a splint. The control unit housing the stimulator may be worn using the shoulder strap provided, or it may be placed on any stable surface. The splint is worn on the hand and forearm. The splint is connected to the control unit by a light cable.
A single channel of constant-voltage symmetrical biphasic Russian waveform stimulation is delivered to the muscles through five surface electrodes. Microprocessor-controlled switching of the stimulation between these five electrodes allows the muscles to be activated in combinations either cyclically or continuously. The stimulation is ramped up at the beginning and down at the end of each cycle.
The electrode locations allow the Handmaster to give finger and thumb extension and flexion. By pressing the Mode button on the Control Unit, the user can select from seven stimulation programs that comprise either cyclic or continuous activation of the finger and thumb extensors and flexors. In addition to the former light glowing presentation of the active mode, the new LCD screen enables also the presentation of the name of active mode and sub-mode. A continuously changing three and two-bar combination indicates that the stimulation phase is active. A "seventh like" object indicates the stimulation intensity or the battery condition.
The user can increase or decrease the stimulation intensity in ten discrete levels by pressing on buttons labeled "+" or "-" on the control unit. This alters the duration of the stimulation pulse. The intensity is displayed as a number (0 to 9) on a seven-segment like display.
During the initial system set-up, the clinician opens a screw secured clinical panel within the control unit. Adjustments are provided for limiting the maximum current to the extensor muscles and to the flexor muscles, along with a global timing factor which increases or decreases the duration of the stimulation cycles, effectively speeding or slowing the cyclic hand motion.
The user starts or stops the stimulation program by pressing a "trigger" button. If required, the user may also stop all stimulation immediately by switching OFF the device.
The Handmaster splint is used to hold the wrist joint at a comfortable extension angle (20°), and also to hold the electrodes on the forearm and hand segments. It is constructed from fiber-reinforced plastic with soft polyurethane cushion sections to distribute stress over bony regions. The electrodes are made from metal mesh. Replaceable water-soaked cloth pads are arranged over the electrodes to provide a conductive interface with the skin. A sponge is provided to facilitate wetting of the electrode pads.
Rechargeable nickel-metal-hydride (NiMH) batteries power the device. Battery status can be displayed both during device operation and while recharging the batteries. Both visual and audio battery-low warnings are provided.
The provided text is a 510(k) summary for the N.E.S.S. HANDMASTER neuromuscular electrical stimulation system. It details device descriptions, predicate devices, intended uses, and a statement of substantial equivalence. However, it does not contain information about specific acceptance criteria or a study that proves the device meets those criteria, as typically found for AI/algorithm-based diagnostic devices.
The document discusses "Performance Data & Substantial Equivalence" and states that "In vitro, biocompatibility, electrical and electromagnetic testing and verification and validation testing of the software were performed to ensure that the modified HANDMASTER does not raise any new questions of safety and efficacy." These are general types of testing for medical devices, but they do not provide specific metrics, acceptance criteria, or study details comparable to what would be expected for an AI system's performance evaluation against a gold standard.
Therefore, most of the requested information cannot be extracted from this document, as it pertains to a different type of device approval process than what would involve the detailed performance metrics and studies characteristic of AI-based medical devices.
Here's a breakdown of what can and cannot be answered based on the provided text:
1. A table of acceptance criteria and the reported device performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Not specified for performance as an algorithm or AI model. Instead, the document discusses general safety and efficacy testing for a hardware device and software validation. | The document states that "In vitro, biocompatibility, electrical and electromagnetic testing and verification and validation testing of the software were performed to ensure that the modified HANDMASTER does not raise any new questions of safety and efficacy." No specific performance metrics (e.g., sensitivity, specificity, accuracy for a diagnostic task) are provided. |
2. Sample sized used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
- Sample Size for Test Set: Not mentioned.
- Data Provenance: Not mentioned.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
- Not mentioned, as the device is a physical stimulator and not an AI diagnostic tool requiring expert-established ground truth on a test set in the conventional sense.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
- Not mentioned.
5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
- No MRMC study is mentioned. This device is a physical neuromuscular electrical stimulator, not an AI-assisted diagnostic tool for human readers.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Not applicable as this is a physical device, not a standalone AI algorithm. Its "performance" refers to its electrical stimulation and physical operation, not an analytical output.
7. The type of ground truth used (expert concensus, pathology, outcomes data, etc)
- Not mentioned, as the concept of "ground truth" for an AI diagnostic algorithm does not directly apply to the performance testing described for this device. The testing focused on general safety, biocompatibility, electrical, electromagnetic, and software validation.
8. The sample size for the training set
- Not mentioned, as this device does not utilize a "training set" in the context of machine learning or AI.
9. How the ground truth for the training set was established
- Not applicable, as there is no mention of a training set or AI model development in the provided text.
Summary regarding the "Study that proves the device meets the acceptance criteria":
The document describes that "In vitro, biocompatibility, electrical and electromagnetic testing and verification and validation testing of the software were performed to ensure that the modified HANDMASTER does not raise any new questions of safety and efficacy." This statement indicates that tests were conducted, but it does not provide details about specific acceptance criteria or the results of these tests in a way that allows for a quantitative performance assessment as would be expected for an AI/algorithm-based device.
The basis for approval is "substantial equivalence" to previously cleared predicate devices (K952273, K982482, and K010837), rather than demonstrating performance against specific, novel acceptance criteria through a detailed clinical or diagnostic accuracy study. The changes made to the device (e.g., display, power supply, battery, materials) required verification of continued safety and efficacy through the mentioned general testing.
§ 882.5810 External functional neuromuscular stimulator.
(a)
Identification. An external functional neuromuscular stimulator is an electrical stimulator that uses external electrodes for stimulating muscles in the leg and ankle of partially paralyzed patients (e.g., after stroke) to provide flexion of the foot and thus improve the patient's gait.(b)
Classification. Class II (performance standards).