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 design of the device provides inputs that can 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 four- /eight-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 Excel (K880088A) EMG instrument.

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.

AI/ML Overview

Here's a breakdown of the acceptance criteria and the study information based on the provided text:

Acceptance Criteria and Device Performance

Criteria	Cadwell Excel with the existing four-/eight-channel preamplifier	Cadwell Excel with the proposed four-/eight-channel preamplifier and buffered input box	Reported Device Performance (Proposed Device)
Safety	Designed to comply with UL 2601-1, CSA C22.2 No. 601.1-M90, and IEC 601-1. Type BF.	Designed to comply with UL 2601-1, CSA C22.2 No. 601.1-M90, and IEC 601-1. Type BF.	Compliant (Implied by "Designed to comply with" and "patient auxiliary current is well below the regulatory limits set forth by IEC 601-1 for BF connections.")
Electrode inputs	20 buffered electrode inputs with built-in full montage selection or 5-pin DIN connector.	20 buffered electrode inputs with built-in full montage selection. One remote buffered electrode input with separate active and reference pin jack connectors or single phono jack connector. Preamplifier fitted with 3-pin DIN connector.	As designed (Functional modification, not a performance metric to be 'met' in the same way as noise or impedance)
Isolation mode rejection	> 110 dB.	> 110 dB.	Compliant (Implied that this specification is met, as no deviation is reported)
Sensitivities	2 micro V/div to 25 mV/div in 13 steps.	2 micro volts/div to 25 mV/div in 13 steps.	Compliant (Implied that this specification is met, as no deviation is reported)
Noise	0.6 micro volts RMS (3 micro V peak to peak) from 10 Hz to 2 kHz typical.	0.6 micro volts RMS (3 micro volts peak to peak) from 10 Hz to 2 kHz typical.	Compliant ("measured value of peak-to-peak noise is less than the allowed value")
Input impedance	> 10,000 Mohms	> 10,000 Mohms	Compliant ("input impedance is greater than 10 Mohms")
Impedance measurement	Built-in individual electrode impedance measurement, including ground.	Built-in individual electrode impedance measurement, including ground.	As designed (Functional similarity)
Calibration	Built-in calibration signal 10 micro V to 50 mV peak to peak, sine or square wave in 13 steps.	Built-in calibration signal 10 micro V to 50 mV peak to peak, sine or square wave in 13 steps.	As designed (Functional similarity)
Artifact suppression	Automatic or manual stimulus artifact suppression.	Automatic or manual stimulus artifact suppression.	As designed (Functional similarity)
Low-cut filters	2-pole filter. Selectable at 0.04, 0.1, 1, 3, 10, 30, 100, 500 Hz.	2-pole filter. Selectable at 0.04, 0.1, 1, 3, 10, 30, 100, 500 Hz.	As designed (Functional similarity)
High-cut filters	Two-channel mode: 2 pole Butterworth--100, 200, 500 Hz; 1, 2, 3, 10, 20 kHz. Four- and eight-channel mode: 2 pole Butterworth--70, 100, 200, 500 Hz; 1, 2, 3, 10, 20 kHz.	Two-channel mode: 2 pole Butterworth--100, 200, 500 Hz; 1, 2, 3, 10, 20 kHz. Four- and eight-channel mode: 2 pole Butterworth--70, 100, 200, 500 Hz; 1, 2, 3, 10, 20 kHz.	As designed (Functional similarity)
Signal Morphology (Nerve Conduction Waveform)	N/A	N/A	Compliant ("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.")
Signal Morphology (EMG Waveform)	N/A	N/A	Compliant ("does not distort the morphology of the EMG waveform when compared to the signal that does not pass through the proposed device.")
Gain	N/A	N/A	Compliant ("gain is not affected by passing the signal through the proposed device.")
Patient Auxiliary Current	N/A	N/A	Compliant ("patient auxiliary current is well below the regulatory limits set forth by IEC 601-1 for BF connections.")

Study Details

The provided text details engineering and clinical tests performed to validate the proposed device.

Sample size used for the test set and the data provenance:
- Clinical Test 6 (Nerve Conduction Waveform): Not specified.
- Clinical Test 7 (EMG Waveform): Not specified.
- Provenance: Not specified (e.g., country of origin, retrospective/prospective). The studies are referred to simply as "clinical tests."
Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not specified. The clinical tests compare the proposed device's signal to the signal that "does not pass through the proposed device," implying a direct comparison without independent expert ground truth establishment in the traditional sense. The "clinical results" suggest expert assessment of waveform morphology, but the number and qualifications of those experts are not provided.
Adjudication method (e.g., 2+1, 3+1, none) for the test set: Not specified.
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: Not applicable. This device is an electromyography (EMG) instrument component, not an AI-assisted diagnostic tool for human readers.
If a standalone (i.e., algorithm only without human-in-the-loop performance) was done: Yes, the device's performance was evaluated in an objective, standalone manner for metrics like gain, noise, input impedance, and patient auxiliary current. The clinical tests also assessed the device's impact on waveform morphology and timing without explicit human interpretation as the primary outcome, but rather the device's fidelity to the original signal.
The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- For electrical/performance metrics (impedance, noise, gain, current): Engineering specifications and regulatory limits (e.g., IEC 601-1).
- For clinical waveform integrity (Nerve Conduction, EMG): Comparison against the signal "that does not pass through the proposed device." This implies the "ground truth" is the unadulterated signal captured by the existing system, and the device's performance is measured by its ability to faithfully reproduce or minimally alter that signal.
The sample size for the training set: Not applicable. This is a hardware modification for an EMG instrument, not a machine learning or AI model that requires a training set.
How the ground truth for the training set was established: Not applicable, as there is no training set for this device.

Summary

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K962458

JAN 1 3 1997

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 Excel and Cadwell Excel Plus

Proposed Device	Order Number
Four-Channel PreamplifierOR	199085-200
Eight-Channel Preamplifier	199088-200
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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3. 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 Excel (K880088A) device. The Cadwell four- /eight-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 device.

Safety of the Cadwell Excel (K880088A) Device

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 Excel (K880088A) Four- /Eight-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 Excel (880088A) Device

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 Somatosensory 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

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.

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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.

5. Statement of Intended Use

Duration of Use

The four- /eight-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.

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6. Comparison of Device Technological Characteristics

The proposed device is a modification to the preamplifier of the Cadwell Excel (K880088A) device. Physical modifications to the predicate device are in the following areas:

The recording component (electrode input box) from the 1. existing preamplifier is placed 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.

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.

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Criteria	Cadwell Excel with the existingfour-/eight-channelpreamplifier	Cadwell Excel with the proposedfour-/eight-channelpreamplifier and buffered inputbox
Safety	Designed to comply withrequirements of UL 2601-1, CSAC22.2 No. 601.1-M90, and IEC601-1. Type BF.	Designed to comply withrequirements of UL 2601-1, CSAC22.2 No. 601.1-M90, and IEC601-1. Type BF.
Electrode inputs	20 buffered electrode inputs withbuilt-in full montage selection or5-pin DIN connector.	20 buffered electrodeinputs with built-in fullmontage selection. One remote bufferedelectrode input withseparate active andreference pin jackconnectors or single phonojack connector. Preamplifier fitted with 3-pin DIN connector.
Isolation moderejection	> 110 dB.	> 110 dB.
Sensitivities	2 micro V/div to 25 mV/div in13 steps.	2 micro volts/div to 25 mV/divin 13 steps.
Noise	0.6 micro volts RMS (3 micro Vpeak to peak) from 10 Hz to 2kHz typical.	0.6 micro volts RMS (3 microvolts peak to peak) from 10 Hzto 2 kHz typical.
Input impedance	> 10,000 Mohms	> 10,000 Mohms
Impedancemeasurement	Built-in individual electrodeimpedance measurement,including ground.	Built-in individual electrodeimpedance measurement,including ground.
Calibration	Built-in calibration signal 10micro V to 50 mV peak to peak,sine or square wave in 13 steps.	Built-in calibration signal 10micro V to 50 mV peak to peak,sine or square wave in 13 steps.
Artifact suppression	Automatic or manual stimulusartifact suppression.	Automatic or manual stimulusartifact suppression.
Low-cut filters	2-pole filter. Selectable at 0.04,0.1, 1, 3, 10, 30, 100, 500 Hz.	2-pole filter. Selectable at 0.04,0.1, 1, 3, 10, 30, 100, 500 Hz.
High-cut filters	Two-channel mode: 2 poleButterworth--100, 200, 500 Hz;1, 2, 3, 10, 20 kHz. Four- andeight-channel mode: 2 poleButterworth--70, 100, 200, 500Hz; 1, 2, 3, 10, 20 kHz.	Two-channel mode: 2 poleButterworth--100, 200, 500 Hz;1, 2, 3, 10, 20 kHz. Four- andeight-channel mode: 2 poleButterworth--70, 100, 200, 500Hz; 1, 2, 3, 10, 20 kHz.

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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 of 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 of 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).