(202 days)
to perform the measurements needed for electromyography (EMG), nerve conduction velocity (NCV, F wave, and H reflex), and evoked potentials (brainstem, visual, and somatosensory), and repetitive nerve stimulation. The purpose of the proposed device is to allow compatibility with high-impedance electrodes. The proposed device allows electrode inouts to be made closer to the source of the signal for reduced signal noise during procedures requiring high-impedance electrodes.
The proposed device consists of the existing four-channel preamplifier and a buffered electrode input box with extension cable. These components provide electrode inputs that are closer to the source of the signal during electromyographic (EMG) testing. The intent of this design is to reduce signal noise during procedures requiring high-impedance electrodes. The proposed device is for use with the Cadwell Sierra (K924723) and 6200A (K931428) EMG instruments.
All device components are reusable and supplied non-sterile. The extension cable with electrode input box is compatible with EtO sterilization guidelines for procedures requiring a sterile field. The input box is available with separate active and reference input connectors or a single phono jack connector.
The attached extension cable connects the input box to the preamplifier by way of a cable adapter. The existing preamplifier will be fitted with three pin DIN connectors to accept the cable adapter.
The extension cable with buffered electrode input box allows electrode inputs to be made closer to the source of the signal for reduced signal noise during procedures requiring high-impedance electrodes. The electrode input box is available with separate active (labeled .) and reference connectors or a single phono jack connector to accommodate recording electrodes with these connector types.
The input box is enclosed in a white polyethylene foam sheath. The sheath houses a circuit board consisting of a buffer circuit, two electrostatic discharge (ESD) networks (one on each side of the buffer circuit), and a separate circuit designed to limit fault currents.
The circuit board is attached to a polyvinyl chloride extension cable terminated in an eight-pin DIN connector. The input box and extension cable are connected to the preamplifier by way of a polyvinyl chloride cable adapter terminated in a three-pin DIN connector. The adapter cable does not qualify as a class II device.
Here's an analysis of the provided text regarding the device's acceptance criteria and studies, structured per your request:
Device: Cadwell Sierra and Cadwell 6200A with the proposed four-channel preamplifier and buffered input box (modification of existing devices).
Purpose of Modification: To allow electrode inputs closer to the signal source for reduced signal noise during procedures requiring high-impedance electrodes.
1. Table of Acceptance Criteria and Reported Device Performance
The document doesn't explicitly state "acceptance criteria" as a separate, quantified list with pass/fail thresholds. Instead, it compares the technical specifications and safety standards of the proposed device against the predicate device, implying that matching or maintaining these characteristics constitutes acceptance. The "Testing and Validation" section then describes specific tests and their outcomes, which serve as evidence of meeting performance expectations.
For the purpose of this request, I will construct a table based on the provided technical comparison and highlight the directly reported performance from the validation section.
| Criteria | Acceptance Criteria (Implied: Match Predicate) | Reported Device Performance |
|---|---|---|
| Safety Compliance | UL 544, IEC 601-1 Type BF (isolated patient connections) | Designed to comply with requirements of UL 544. Classification: isolated patient connections IEC 601-1: Type BF. |
| Electrode Inputs | Four buffered electrode inputs with separate active & reference 1.5-mm touch-proof connectors; One remote buffered electrode input for separate active & reference pin jack connectors or single phono jack connector; Preamplifier fitted with 3-pin DIN connector. (This is a description of the new setup, not an acceptance value.) | N/A (This describes the feature, not a performance metric for it. The performance relates to noise reduction and signal integrity.) |
| Isolated Ground Connections | 2 connection | 2 connection |
| Isolation Mode Rejection | > 150 dB. | > 150 dB. |
| Common Mode Rejection | 90 dB | 90 dB. |
| Sensitivities | 2, 5, 10, 20, 50, 100, 200, 500 micro V/div; 1, 2, 5, 10, 20 m V/div. | 2, 5, 10, 20, 50, 100, 200, 500 micro V/div; 1, 2, 5, 10, 20 m V/div. |
| Noise (Electrical) | 2 micro V peak to peak (10 Hz to 10 kHz). | The measured value of peak-to-peak noise is less than the allowed value (2 micro V peak to peak (10 Hz to 10 kHz)). |
| Input Impedance | > 1,000 Mohms (common mode) | The input impedance is greater than 10 Mohms when the active and reference connectors are subjected to ten strikes of 8-kV ESD each. (This is a specific test result, not a direct match to the >1000 Mohms spec, but likely demonstrating robust performance under stress.) |
| Notch Filter | 50 or 60 Hz | 50 or 60 Hz |
| Low-cut Filters | 1- or 2-pole filter. Selectable at 0.04, 0.1, 1, 3, 10, 30, 100, 500 Hz. | 1- or 2-pole filter. Selectable at 0.04, 0.1, 1, 3, 10, 30, 100, 500 Hz. |
| High-cut Filters | 2-pole (12 dB/octave) filter. Selectable at 30, 50, 100, 200, 300, 500 Hz; 1, 1.5, 2, 3, 5, 10, 15 kHz. | 2-pole (12 dB/octave) filter. Selectable at 30, 50, 100, 200, 300, 500 Hz; 1, 1.5, 2, 3, 5, 10, 15 kHz. |
| Common Recording Reference Input | 1 input | 1 input |
| Temperature Probe Input | 20 to 45 °C | 20 to 45 °C |
| Gain | (Implied: No significant change or distortion) | Not affected by passing the signal through the proposed device. |
| Patient Auxiliary Current | (Implied: Below regulatory limits for BF connections) | Well below the regulatory limits set forth by IEC 601-1 for BF connections. |
| Nerve Conduction Waveform Morphology | (Implied: No distortion) | Does not distort the morphology of the nerve conduction waveform, nor does it significantly affect the onset time, peak time, or amplitude when compared to the signal that does not pass through the proposed device. |
| EMG Waveform Morphology | (Implied: No distortion) | Does not distort the morphology of the EMG waveform when compared to the signal that does not pass through the proposed device. |
2. Sample Size Used for the Test Set and Data Provenance
The document does not explicitly state the sample size for clinical tests (Test 6 and Test 7). It mentions "clinical results" but provides no information on the number of subjects, cases, or specific data provenance (country of origin, retrospective/prospective). This information seems to be deferred to "Enclosure 3 of the previous submission dated October 16, 1996."
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not specify the number or qualifications of experts used to establish ground truth for the clinical tests (Test 6 and Test 7). It refers to the interpretation of waveform morphology, onset time, peak time, and amplitude, which would typically involve expert analysis in electrophysiology, but no details are provided.
4. Adjudication Method for the Test Set
The document does not describe any specific adjudication method (e.g., 2+1, 3+1, none) for the test set.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No MRMC study is mentioned. The device is an electrophysiology component designed to improve signal quality, not an AI diagnostic tool requiring multiple human readers to interpret its output in a comparative effectiveness study. The "clinical results" described are a comparison of signals with and without the proposed device, not a human-AI comparison.
6. Standalone Performance Study
Yes, a standalone performance assessment was conducted for the device in its intended function. The "Testing and Validation" section describes engineering and clinical tests (Tests 1-7) where the device's performance properties (input impedance, gain, noise, patient auxiliary current, waveform morphology) were measured and compared against regulatory limits or control signals (signals not passing through the device). This assessed the algorithm (or in this case, the hardware modification) performance in isolation.
7. Type of Ground Truth Used
The ground truth for the engineering tests (Tests 1-5) appears to be:
- Regulatory Limits: For patient auxiliary current (IEC 601-1), allowed noise levels.
- Engineering Specifications: For input impedance, gain (expected to be unchanged).
- Control Measurements: Direct comparison to signals that do not pass through the proposed device for gain and noise.
For the clinical tests (Tests 6-7), the ground truth was:
- Comparison to Signals Without the Device: Waveform morphology, onset time, peak time, and amplitude were compared to signals obtained without passing through the proposed device, with the expectation that these characteristics should not be significantly distorted. This implies a baseline reading from the existing system serves as a form of ground truth for assessing non-inferiority or lack of distortion.
8. Sample Size for the Training Set
The document does not refer to a "training set" in the context of machine learning or AI. This device is a hardware modification for an electromyography instrument, not an AI algorithm that undergoes training. The "testing and validation" described pertains to verifying the physical and functional aspects of the hardware.
9. How the Ground Truth for the Training Set Was Established
As there is no "training set" in the AI sense for this device, this question is not applicable.
§ 882.1870 Evoked response electrical stimulator.
(a)
Identification. An evoked response electrical stimulator is a device used to apply an electrical stimulus to a patient by means of skin electrodes for the purpose of measuring the evoked response.(b)
Classification. Class II (performance standards).