The Medi-Dx 7000 is a diagnostic device for the quantitative detection of sensory neurological imparments. The population of subjects for whom this device may be used for diagnostic purposes would include any individual capable of communicating their perception of cutaneous sensation.

The Medi-Dx 7000 diagnostic examination may be conducted as part of a routine neurological examination or as a screening procedure for the detection of peripheral neuropathy which may be caused by various pathological conditions or exposures to toxic substances.

Device Description

Approved 12/01/97, the Medi-Dx 7000 is a Current Perception Threshold (CPT) device for the examination of peripheral neuropathies. It generates sinusoidal electrical currents in the 5 Hz, 250 Hz and 2000 Hz frequencies from 0 mA to 9.99 mA.

The Medi-Dx 7000 weighs approximately 15 Ibs. and is housed within a 12" x 5" x 11" heavy duty plastic case with metal face and rear panels. The rear panel has an access door for installation and replacement of (8) standard (6) Volt Alkaline Batteries. The Face panel has an 'ON/OFF' switch, a 'Battery Test' switch (also functioning as an automatic calibration switch), and three (3) switches, one for each of the frequencies; 5 Hz, 250 Hz and 2000 Hz respectively. The intensity control is immediately below an LCD which reads mA output. Two ports are available on the from panel for connection with electrodes.

AI/ML Overview

The provided text does not contain detailed acceptance criteria for the Medi-Dx 7000 device, nor does it describe a specific study that formally proves the device meets such criteria with quantitative performance metrics.

However, based on the information provided, the submission emphasizes substantial equivalence to a predicate device (Neurometer) rather than presenting a performance study against specific acceptance criteria. The manufacturer's argument for equivalence is based on shared functional and technical characteristics, and improved safety features of the Medi-Dx 7000.

Here's an attempt to structure the information based on your request, highlighting what is implicitly or explicitly stated and what is missing:

Acceptance Criteria and Reported Device Performance

Acceptance Criteria (Implied/Stated)	Reported Device Performance (as stated in the submission)
Functional Equivalence:	Current output, waveform, minimum/maximum output (0.0 mA to 9.99 mA), and frequencies (5 Hz, 250 Hz, 2000 Hz) are the same as the predicate device.
Safety:	The Medi-Dx 7000 offers "improved safety" compared to the equivalent device. Specific safety features include: isolated output via transformer (unlike predicate), largely non-conducting plastic case (unlike predicate's all-metal case), output dampening to prevent electrical field build-up at electrodes under no-load conditions (not known for predicate), four independent clocks for frequency production (does not produce RFI, unlike predicate), and a safety interlock.
Biological Compatibility & Patient/Operator Safety:	Both devices "deliver current to the subject that is biologically compatible and posses no threat of injury to the patient or operator."
Accuracy/Calibration:	Both manufacturers "burn in the devices for 168 hours and testing insures accuracy/calibration." (No specific accuracy metrics are provided).
Environmental Risk:	Neither device poses "any environmental risk from chemical, thermal, radiation or mechanical factors."
Display/User Interface:	The Medi-Dx 7000 has a "digital LCD output meter" (predicate does not). Both use an LCD readout of current.
Battery Level Warning:	The Medi-Dx 7000 "WARNING" light flashes if power drops below that needed for max output. (Predicate has a "steady on" warning for low batteries and flashing for waveform clipping).
Clinical Performance for Diagnosing Neuropathies: (Implied)	The submission argues that "it is reasonable to assume that the two devices are the same in function and reliability" due to shared output characteristics. It also states that several physicians have compared the devices clinically and "have agreed to share their opinions if contacted." However, no formal study results are provided.

Study Details

The submission describes a comparison to a predicate device for substantial equivalence, rather than an independent performance study with quantitative acceptance criteria. Therefore, many of the requested details are not explicitly provided.

Sample size used for the test set and the data provenance:
- Test Set Sample Size: Not specified. The submission mentions that "several of these physicians have compared the devices clinically," implying some form of clinical observation or comparison, but no formal test set size is given.
- Data Provenance: Not specified. It's unclear if objective data was collected, or if it refers to anecdotal clinical experience from unnamed physicians.
Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Number of Experts: "Several" physicians are mentioned.
- Qualifications of Experts: They are described as "neurologists and other medical experts." No specific experience or board certifications are provided.
Adjudication method for the test set:
- Adjudication Method: Not specified. It appears to be based on "opinions" of physicians rather than a formal adjudicated consensus process.
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:
- MRMC Study: No, this type of study was not described. The device is not an AI-assisted diagnostic tool. The comparison is between two CPT (Current Perception Threshold) devices. The discussion around physicians' opinions is anecdotal and not a formal MRMC study.
- Effect Size: Not applicable.
If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Standalone Performance: Not applicable in the context of an algorithm. This device is a measurement tool. Its "standalone" performance would relate to its physical output characteristics, which are stated to be equivalent to the predicate device. The submission makes a case for the device's inherent functional equivalence and improved safety features.
The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- Ground Truth: Based on the text, the "ground truth" for the clinical comparison was essentially the clinical judgment and opinion of the consulted neurologists and medical experts regarding the device's ability to elicit threshold perception without "over stimulating" receptors, and its overall functional performance in line with the predicate device. There is no mention of an objective, independent ground truth like pathology or outcomes data.
The sample size for the training set:
- Training Set Sample Size: Not applicable. This submission concerns a medical device, not a machine learning algorithm requiring a "training set."
How the ground truth for the training set was established:
- Training Set Ground Truth: Not applicable.

Summary

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MAY 2 0 1998

510 (k) SUMMARY 807.92

K980866

James L. Hedgecock, DC, PhD Submitted:

445 Dartmoor Street Laguna Beach, CA 92651 Voice: 714-497-1207 Fax: 714-497-8437

Contact person:	Dr. James L. Hedgecock
Date Submitted:	11/06/97
Name of Device:	Medi-Dx 7000 510 (k) 964622
Equivalent Device:	Neurometer by Neurotron; 510(k) 853608

This Summary is the same as the previously accepted one with the exception of the inclusion of the AMREX electrodes mentioned in the GENERAL COMPARISON (below).

GENERAL DESCRIPTION OF THE MEDI-DX 7000:

INDICATIONS AND USAGE:

The Medi-Dx 7000 is a diagnostic device for the quantitative detection of sensory neurological impairments. The population of subjects for whom this device may be used for diagnostic purposes would include any individual capable of communicating their perception of cutaneous sensation.

GENERAL COMPARISON:

The Medi-Dx 7000 and the equivalent (Neurometer) device are essentially the same, they weigh and have approximately the same size. Both have the same minimum / maximum output (0.0 mA to 9.99 mA). The same current characteristic (sinusoidal waveform) and the same frequencies (5 Hz, 250 Hz and 2000Hz). The Medi-Dx 7000 can be used with the electrodes of the equivalent device or with electrodes distributed by AMREX. The AMREX system is made up of a large general ground electrode and a small single electrode. The Medi-Dx 7000 is shipped with whichever electrodes the purchaser has chosen.

TECHNICAL DIFFERENCES:

The Medi-Dx 7000 does not have a built in battery charger, as does the equivalent device (Neurometer), which is powered by NiCd rechargeable batteries with a built in recharger.
The Medi-Dx 7000 is fully manually controlled and the Neurometer has a manual and an auto-test mode.
The Medi-Dx 7000 uses the voltage as-is without stepping up, so the maximum available voltage is +5 v to -5 v to operate the internal circuitry. The equivalent device has a step up of 10 times with an internal switching power supply, so the maximum voltage is +85 v to -85 v to operate the internal circuitry.

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Page 2 510 (k) SUMMARY 807.92 Medi-Dx 7000 Continued:

The Medi-Dx 7000 has an isolated output via the transformer. No transformer isolation of output is used in the equivalent device, which depends on non-failure of the charger and selector switch to prevent 110v AC leakage.
The Medi-Dx 7000 case is largely non-conducting plastic, whereas the equivalent device has an all metal case.
No-load conditions will not build up an electrical field at the electrodes, because the output is dampened. It is not known if the equivalent device has such output dampening. 7) Four independent clocks for frequency production are used in the Medi-Dx 7000 device. The equivalent device uses one master clock which is Crystal controlled. The

result is that the equivalent device produces RFI and the Medi-Dx 7000 does not.

The Medi-Dx 7000 has a safety interlock which disconnects the power supply if the case is opened.
The Medi-Dx 7000 has a digital LCD output meter and the equivalent device does not.

SIMILARITIES:

The following technical similarities are noted:

The Medi-Dx 7000 "WARNING" light flashes if the power drops below that needed to supply the maximum output of 9.99 mA. The equivalent device has a "WARNING" light that is "steady on" to warn of low batteries. This same light is used to warn of clipping of the waveform. In the case of clipping, the Warning light will flash when the intensity is increased, whereas the warning light will flash at 0 (zero) when the battery is low. 2) Neither device posses any environmental risk from chemical, thermal, radiation or mechanical factors.
Both devices deliver current to the subject that is biologically compatible and posses no threat of iniury to the patient or operator.
Both use an LCD readout of current.
Both use a master power switch.
The Medi-Dx 7000 uses separate switched to isolate each frequency and two switches cannot be turned on at the same time. The equivalent device uses a selector knob to isolate the frequencies.
Both use a digital waveform filter to produce and analog output.
Both manufacturers "burn in the devices for 168 hours and testing insures accuracy/calibration.

Tests and trials:

Since the current output, waveform are the same, it is reasonable to assume that the two devices are the same in function and reliability.

It will be noted that almost all the differences relate to improved safety of the Medi-Dx 7000 as compared to the equivalent device. The only difference in operation is that the Medi-Dx 7000 does not use an auto-test mode, which is employed in the equivalent device. This auto-test mode is employed in such a way that the subject is purposely stimulated above the threshold and then below in such as fashion as to "home in" on the threshold. However, it is the contention of the Medi-Dx 7000 manufacturer and the opinion of neurologists and other medical experts the manufacturer has consulted with. that this practice can in practice actually alter the threshold by "over stimulating" the receptors and any supposed advantage in accuracy by testing in this auto-test mode is out weighed by the fact that this auto-test mode may be slightly increasing the current required to produce a threshold stimulation. In other words the over stimulation of the receptors causes receptor fatigue and more receptors, i.e. more current, is required to reach a threshold stimulation with each stimulation above the threshold. Several of these physicians have compared the devices clinically and have agreed to share their opinions if contacted. Their names and phone numbers will be supplied upon request.

Sincerely.

Sam Hedjar

James L. Hedgecock

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Image /page/2/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo features a stylized caduceus symbol, which is a staff with two snakes entwined around it. The words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" are arranged in a circular pattern around the caduceus.

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

MAY 20 1998

James L. Hedgecock, Ph.D. ·Neuro-Diagnostic Associates 445 Dartmoor Street 92651 Laquna Beach, California

Re: K980866 Medi-Dx 7000 with AMREX Electrodes Trade Name: Requlatory Class: II Product Code: GWF Dated: February 17, 1998 February 19, 1998 Received:

Dear Dr. Hedgecock:

We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Druq, and Cosmetic Act (Act). You may, therefore, market the device, subject to the general controls provisions The general controls provisions of the Act of the Act. include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.

If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Requlations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the current Good Manufacturing Practice requirement, as set forth in the Quality System Regulation (QS) for Medical Devices: General requlation (21 CFR Part 820) and that, through periodic (QS) inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP requlation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or requlations.

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Page 2 - Dr. Hedgecock

This letter will allow you to begin marketing your device as described in your 510 (k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4595. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to
premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its internet address "http://www.fda.qov/cdrh/dsmamain.html".

Sincerely yours,

C. Calvin McCriston, Ph.D.

a M. Witten, Ph.D., M.D. Director Division of General and Restorative Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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INDICATIONS FOR USE:

(k) 880866

DEVICE NAME: MEDI-DX 7000 with AMREX ELECTRODE

INDICATIONS FOR USE:

Concurrence of CDRH, Office of Device Evaluation (ODE)

Prescription Use(Per 21 CFR 801.109)	OR	Over-The-Counter-Use(Optional Format 1-2-96)

(Division Sign-Off)

Division of General Restorative Devices

510(k) Number	K990866
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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).