The general purpose of the proposed device is identical to the predicate device: "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 inputs to be made closer to the source of the signal for reduced signal noise during procedures requiring high-impedance electrodes.

Device Description

The proposed device consists of the existing two-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 polvyinyl chloride cable adapter terminated in a three-pin DIN connector. The adapter cable does not qualify as a class II device.

AI/ML Overview

This document describes a modification to an existing Electromyography (EMG) and Evoked Potential (EP) equipment. The modification involves adding a buffered input box with an extension cable to allow electrode inputs closer to the signal source, aiming to reduce signal noise during procedures requiring high-impedance electrodes. The existing preamplifier is also modified to accommodate this new component.

Here's an analysis of the acceptance criteria and study that proves the device meets them:

1. Table of Acceptance Criteria and Reported Device Performance

The document doesn't explicitly list "acceptance criteria" in a separate section, but rather presents a comparison of technical specifications between the existing and proposed devices, along with results from specific engineering and clinical tests. We can infer the acceptance criteria from these comparisons and test descriptions.

Criteria	Acceptance Criteria (Inferred)	Reported Device Performance (Proposed Device)
Safety:
IEC 601-1 / UL 544 Compliance	Device must comply with IEC 601-1 (Type BF) and UL 544.	Designed to comply with requirements of UL 544. Classification: isolated patient connections IEC 601-1: Type BF.
ESD withstand	Input impedance > 10 Mohms after 8-kV ESD strikes.	Results of engineering tests 1 and 2 indicate that the input impedance is greater than 10 Mohms when the active and reference connectors are subjected to ten strikes of 8-kV ESD each.
Gain Preservation	Gain should not be affected by passing signal through the device.	The results from test 3 show that the gain is not affected by passing the signal through the proposed device.
Patient Auxiliary Current	Patient auxiliary current must be well below IEC 601-1 limits.	The results from test 4 show that the patient auxiliary current is well below the regulatory limits set forth by IEC 601-1 for BF connections.
Noise Reduction	Measured peak-to-peak noise must be less than the allowed value.	The results from test 5 show that the measured value of peak-to-peak noise is less than the allowed valued. (Specific allowed value not stated, but implied to be met).
Clinical Performance:
Nerve Conduction Waveform Preservation	No distortion of waveform and no significant effect on onset time, peak time, or amplitude.	Clinical results from test 6 show that the proposed device 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 Preservation	No distortion of EMG waveform.	Additional clinical results in test 7 indicate that the proposed device does not distort the morphology of the EMG waveform when compared to the signal that does not pass through the proposed device.
Electrical Specifications (Identical to predicate)	CMRR > 100 dB, Input Impedance > 1,000 Mohms (common mode), Noise 2 micro V peak to peak (10 Hz to 10 kHz), etc.	All electrical specifications (Isolation mode rejection, Common mode rejection, Sensitivities, Noise, Input impedance, Notch filter, Low-cut filters, High-cut filters) are reported as identical to the predicate device, indicating they meet the established performance benchmarks.

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

The document does not explicitly state the sample size for the test set used in the engineering or clinical tests (tests 1-7).
The data provenance is also not specified (e.g., country of origin, retrospective or prospective). It only mentions "clinical results from test 6" and "additional clinical results in test 7."

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 of experts used or their qualifications for establishing ground truth in the clinical tests. The clinical tests compare the device's output to signals that do not pass through the proposed device.

4. Adjudication Method for the Test Set

The document does not describe any adjudication method (e.g., 2+1, 3+1) for the test set. The clinical results seem to be based on a direct comparison of waveforms.

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

No, an MRMC comparative effectiveness study was not done. The document describes engineering and clinical tests focused on verifying the device's signal integrity and safety, not on comparing human reader performance with and without AI assistance. The device itself is a hardware modification (buffered input box) for an EMG/EP system, not an AI-assisted diagnostic tool.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

The concept of "standalone performance" typically applies to diagnostic algorithms. Since this device is a hardware component for an existing EMG/EP instrument, a standalone algorithm performance study is not applicable. The tests performed assess the hardware's impact on signal quality and electrical safety.

7. The Type of Ground Truth Used

For the engineering tests (ESD, Gain, Patient Auxiliary Current, Noise), the "ground truth" is based on established engineering standards and regulatory limits (e.g., IEC 601-1, UL 544, and internal specifications for gain, noise, and impedance).

For the clinical tests (Nerve Conduction and EMG Waveform Preservation), the ground truth is established by comparison to signals that do not pass through the proposed device. This implies an internal control where the same physiological event is recorded with and without the new component, and their waveform characteristics are compared. This method relies on the existing, well-understood properties of normal nerve conduction and EMG waveforms.

8. The Sample Size for the Training Set

The device is a hardware modification, not a machine learning algorithm that requires a training set. Therefore, there is no training set in the context of this submission.

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

As there is no training set for this hardware device, this question is not applicable.

Summary

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K9689457

JAN | 3 |997

Section 2 - Summary and Certification

December 20, 1996

A. 510(k) Summary of Safety and Effectiveness

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.

1. Submitter Name and Identification

Cadwell Laboratories, Inc. 909 North Kellogg Street Kennewick, WA 99336 (800) 245-3001 Contact: Chris Bolkan Establishment Registration Number: 3020018

2. Proposed Device Name and Part Number

Trade Name (Proprietary Name): Cadwell Sierra and 6200A

Proposed Device	Order Number
Two-Channel Preamplifier	190152-200
Buffered Input Box with Extension Cable	197112-200
Cable Adapter	199155-200

Common Name or Usual Name: Electromyography and Evoked Potential Equipment.

Classification: Type II

Name	Number
Electromyograph	84GWP
Electromyograph, Diagnostic	89IKN

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1. Identification of the Substantially Equivalent Device
  Reason for Premarket Notification: Modification to an existing device.

Modification of Existing Device: The proposed device is a modification to the existing Cadwell Sierra (K924723) and 6200A (K931428) devices. The Cadwell two-channel preamplifier with buffered input box allows electrode inputs to be made closer to the signal source for reduced noise during procedures requiring high-impedance electrodes. The proposed device complies with the same safety standards as the existing devices.

Safety of the Cadwell Sierra (K924723) and 6200A (K931428) Devices

The original device complies with the following safety standards for medical equipment:

IEC 601-1 Medical Electrical Equipment. Part 1. General requirements for safety. Type: Class 1 or grounded equipment, continuous operation, with B and BF applied parts.
IEC 878 (1988) Graphic symbols for electrical equipment in medical practice.
NFPA 99. Standard for Health Care Facilities.

The original device complies with the following general safety standards for electrical equipment:

ANSI/NFPA No. 70 (1990) National electric code.
UL 796 Standard for printed wiring boards.
UL 94 Standard for tests for flammability of plastic materials for parts in devices and appliances.

Safety of the Cadwell Sierra (K924723) and 6200A (K931428) Two-Channel Preamplifier Device

The original device complies with the following standards:

IEC 601-1 isolated applied part Type BF.

American Electroencephalographic Society Guidelines for Clinical Evoked Potential Studies, 1984. Section III. Standards for Clinical Evoked Potential Equipment: Minimal Standards, Amplifier Averager. Section IV. Standards for Clinical Evoked Potential Recording: Calibration.

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Effectiveness of the Cadwell Sierra (K924723) and 6200A (K931428) Devices

The original device is designed to perform the measurements needed for electromyography (EMG), nerve conduction velocity (NCV. F wave, and H reflex), evoked potentials (brainstem, visual, somatosensory) and repetitive nerve stimulation. The effectiveness of these clinical protocols is described in standard medical school textbooks. Please refer to the following texts for additional information.

Aminoff MJ: Electrodiagnosis in Clinical Neurology, Churchill Livingstone Inc., 1980.
Chiappa KH: Evoked Potentials in Clinical Medicine, ed 2. Raven Press, 1990.
Delisa JA: Manual of Nerve Conduction Velocity and Somatosensory Evoked Potentials, ed 2. Raven Press, 1987.
Johnson EW: Practical Electromyography, ed 2, Williams & Wilkins, 1988.
Kimura J: Electrodiagnosis in Diseases of Nerve and Muscle: Principles and Practice, ed 2. A Davis Company, 1989.
Spehlmann R: Evoked Potential Primer: Visual, Auditory, and Somatosensorv Evoked Potentials in Clinical Diagnosis, Butterworth Publishers, 1985.
Regan D: Human Brain Electrophysiology: Evoked Potentials and Evoked Magnetic Fields in Science and Medicine. Elsevier Science Publishing Co., Inc., 1989.

4. Description of the Proposed Device

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5. Statement of Intended Use

Duration of Use

The two-channel preamplifier with buffered input box is designed for use during the duration of the procedure only. This device is not for chronic use and is labeled accordingly .

Intended Use Environment

Use of the proposed device is to be administered under the direction of a trained physician, surgeon, neurologist, or electrophysiologist in a suitable operating room or clinic.

6. Comparison of Device Technological Characteristics

The proposed device is a modification to the Sierra (K924723) and 6200A (K931428) preamplifier devices. Physical modifications to the predicate device are in the following areas:

1. The recording component (electrode input box) from the existing preamplifier is mounted at the end of the extension cable. The proposed device provides closer electrode inputs for reduced signal noise during procedures requiring high-impedance electrodes.
1. The proposed input box and extension cable are compatible with EtO sterilization requirements.
1. To accommodate the proposed input box and extension cable, the existing preamplifier requires a hardware upgrade from the existing five-pin DIN connector to a three-pin DIN connector. The proposed device also requires a preamplifier cable adapter. The cable adapter does not qualify as a class II device.

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The proposed device and the predicate device have nearly identical technical specifications and characteristics. The modification consists of adding a remote electrode input box for use with a single, high-impedance electrode. The input box connects to the existing preamplifier by way of an extension cable and cable adapter. The cable adapter requires a three-pin DIN connector in place of the standard five-pin DIN connector currently on the preamplifier.

Criteria	Cadwell Sierra and 6200A withthe existing two-channelpreamplifier	Cadwell Sierra and 6200A withthe proposed two-channelpreamplifier and buffered inputbox
Safety	Designed to comply withrequirements of UL 544.Classification: isolated patientconnections IEC 601-1: TypeBF.	Designed to comply withrequirements of UL 544.Classification: isolated patientconnections IEC 601-1: TypeBF.
Electrode inputs	Two buffered electrode inputswith separate active andreference 1.5-mm touch-proofconnectors or 5-pin DINconnector.	Two buffered electrodeinputs with separate activereference 1.5-mm touch-proof connectors.One remote bufferedelectrode input for separateactive and reference pinjack connectors or singlephono jack connector.Preamplifier fitted with 3-pin DIN connector
Isolated groundconnections	1 connection	1 connection
Isolation moderejection	> 150 dB.	> 150 dB.
Common moderejection	> 100 dB	> 100 dB.
Sensitivities	2, 5, 10, 20, 50, 100, 200, 500micro V/div; 1, 2, 5, 10, 20 mV/div.	2, 5, 10, 20, 50, 100, 200, 500micro V/div; 1, 2, 5, 10, 20 mV/div.
Noise	2 micro V peak to peak (10 Hz to10 kHz).	2 micro V peak to peak (10 Hz to10 kHz).
Input impedance	> 1,000 Mohms (commonmode)	> 1,000 Mohms (commonmode)
Notch filter	50 or 60 Hz	50 or 60 Hz
Low-cut filters	1- or 2-pole filter. Selectable at0.04, 0.1, 1, 3, 10, 30, 100, 500Hz.	1- or 2-pole filter. Selectable at0.04, 0.1, 1, 3, 10, 30, 100, 500Hz.
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.
Temperature probeinput	20 to 45 °C	20 to 45 °C

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Testing and Validation

The proposed device underwent engineering and clinical testing to validate that the device functions as a remote buffer preamplifier when used with the appropriate electrodiagnostic device. For validation procedures and results, please see Enclosure 3 of the previous submission dated October 16, 1996.

Conclusion

The results of engineering tests 1 and 2 indicate that the input impedance is greater than 10 Mohms when the active and reference connectors are subjected to ten strikes of 8-kV ESD each.

The following tests were carried out with the proposed device connected to the intended electrodiagnostic instrument. The results from test 3 show that the gain is not affected by passing the signal through the proposed device. The results from test 4 show that the patient auxiliary current is well below the regulatory limits set forth by IEC 601-1 for BF connections. The results from test 5 show that the measured value of peak-to-peak noise is less than the allowed valued.

Clinical results from test 6 show that the proposed device 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. Additional clinical results in test 7 indicate that the proposed device does not distort the morphology of the EMG waveform when compared to the signal that does not pass through the proposed device.

Regulation Number and Section

§ 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).